A systematic exploration of the nutritional benefits and therapeutic potential of Mesembryanthemum forsskalii

Abstract

This systematic review highlights the urgent need to explore the nutritional and therapeutic potential of Samh, or Mesembryanthemum forskahlii Hochst. ex Boiss. (M. forskalii) in response to global health challenges and the growing interest in functional foods. Out of 184 records, 30 were chosen for the systematic review, comprising 24 articles and 6 books. The review revealed that 83.33% of the studies concentrated on samh seeds. A comprehensive analysis identified 128 distinctive compounds and categorised them into 10 classes, with amino acids being the most abundant, followed by phenolics, minerals, flavonoids, carboxylic acids, proteins, and lipids. The review highlights various biological properties associated with seed extracts, including antidiabetic properties, regulatory effects on triglycerides and cholesterol levels, and reductions in oxidative stress and gastrointestinal ulcers. The fruit extract was noted to enhance liver function in mice with CCl₄-induced toxicity. Although the extract from Samh’s seeds did not show antimicrobial effects, silver nanoparticles derived from the extract were highly effective against bacteria and fungi. Furthermore, while preliminary findings suggest beneficial health effects, the limited toxicological research necessitates further investigation into the safety profile of M. forskahlii. Understanding the potential toxic effects and safe dosage levels is crucial, especially for populations using this plant as a traditional remedy or dietary supplement. This review emphasises the potential of M. forskalii as a functional food that can enhance dietary diversity and promote well-being. The review advocates further research into all parts of the plant to harness their health-promoting potential fully, integrating traditional knowledge into contemporary nutritional practices.

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Introduction

Investigations on indigenous plants have been accentuated as dietary patterns worldwide move towards incorporating functional foods, especially considering the possible health benefits and roles of these plants in promoting food security (Sundarrajan & Bhagtaney, 2024). Furthermore, due to global warming and water scarcity, several studies have been done on the possible uses of tolerant plants as sources of food, feed, cosmetics, and pharmaceuticals. A captivating story of this growing scholarly interest in plants is revealed in a systematic survey of the literature on the Mesembryanthemum forskahlii Hochst. ex Boiss. (M. forskalii) also known as Opophytum forskahlii Hochst. ex Boiss. (O. forskalii), and as samh in Arabic culture. This succulent plant, which is native to arid regions, is prised for both its remarkable environmental adaptations and its potentially health-friendly properties, as have been demonstrated in numerous studies. As the world’s population looks for more nourishing and sustainable food sources, it is critical to comprehend the phytochemical makeup and nutritional profile of the plant (Ghazanfar, 1994; Mandaville, 2013).

Historically, samh has been a vital wild food source for the Bedouin people in northern Arabia, alongside nakhl (date palm) and fage (desert truffles). It serves as a grain substitute for those unable to afford wheat or rice. Explorer William Palgrave noted its significance, describing it as “a main article of subsistence for the Bedouins of Northern Arabia” (Mandaville, 2004). Traditionally, ground samh seed flour is used in various recipes by indigenes of the northern regions of Saudi Arabia. Notable dishes include A1-Batholelaah (coarsely ground roasted seeds), Al-Lahmah (smoothly ground seeds for travellers), Al-Baseesah (combined with date molasses or butter), Aseedah (thick paste mixed with milk or butter), A1-Bekailah (with dates and butter), and samh bread (dough made from unroasted seeds baked over firewood ash) (Al-Khaldi, 2019; Al-Shrari, 2019; Mustafa et al., 1995).

Mesembryanthemum forskahlii Hochst. ex Boiss. (Opophytum forskahlii) belongs to the Aizoaceae family (Ghazanfar, 1994; Mandaville, 2013). This succulent annual plant grows 10–25 cm tall with upright stems (Figure 1). Its leaves are sub-terete, succulent, and conical, measuring 5 cm long and 1.5 cm thick. The flowers feature unequal lobes, white-to-cream petals, and a yellowish centre, with capsules 12–15 mm long containing seeds (Al-Jassir et al., 1995b; Ghazanfar, 1994; Mandaville, 2013). The capsules hold seeds called kacbar (sbib), which are dark brown, hard, small, and spherical (Al-Shrari, 2019; Mandaville, 2004). The anatomical structure of the seed shows a curved embryo and endosperm (Al-Jassir et al., 1995a).

Research on the samh plant (M. forskalii) has surged recently, driven by increased interest in nutrition and traditional remedies (Bold et al., 2020; Mirzaie et al., 2020; Varzakas & Smaoui, 2024). The seeds exhibit significant antidiabetic effects, normalising triglyceride and cholesterol levels in diabetic mice (Al-Faris et al., 2010, 2011). They also demonstrate antiulcerogenic potential by reducing stomach lesions and oxidative stress (Foudah et al., 2022). The fruit extract improves liver function in CCl4-toxified mice by restoring liver enzymes and Bcl-2 levels (Mahalel et al., 2023). Silver nanoparticles from the seeds show antibacterial and antifungal properties, particularly against Candida albicans, while the seed extract lacks antimicrobial activity against 20 tested pathogens (Aabed & Mohammed, 2021). The seeds possess significant antioxidant activity, enhanced by phenolic and glucosinolate compounds, especially postfermentation and germination (Ahmed et al., 2020; Bilel et al., 2020; Hamed et al., 2016; Mohammed et al., 2023). Research on the samh plant predominantly focuses on its seeds, which constitute a significant portion of publications. This emphasis allows food scientists to explore the seeds’ nutritional value and potential health-promoting applications. However, limited studies on other plant parts, such as shoots, leaves, flowers, and roots, highlight a knowledge gap. Therefore, researchers are encouraged to expand their investigations beyond the seeds for a more comprehensive understanding of the entire plant.

The dynamic research landscape on M. forskalii is represented in the graphs and tables in this review, to highlight the need for more in-depth investigations of its various parts to increase recognition of the significance of the plant for health and nutrition and the bioactive compounds it contains. Future research should focus on elucidating the specific mechanisms by which their bioactive compounds exert their effects, as well as the impact of various treatment processes on their physicochemical and functional properties. Additionally, clinical studies are needed to assess the health benefits of M. forskalii in diverse populations. Addressing these areas could lead to innovative food solutions that promote environmental sustainability and meet contemporary dietary needs.

Methodology

Search strategy

The systematic review approach was done by obtaining the results of a literature search covering the last 30 years (1994–2024). The search was carried out during August 2024 in the following major databases: Web of Science, PubMed, and EBSCO. This systematic review was restricted to articles published in the English language. The manual search included a language exception due to the plant’s origin: six books written in Arabic and English were included covering the botanical, historical, geographical, cultural, and anthropological parts. We retrieved the scientific terminology of the plant from the plant list (http://theplantlist.org/), which provided the Latin name of the plant species. The following keywords were employed in the search: “Mesembryanthemum forsskalii Hochst. ex Boiss.,” “Mesembryanthemum forsskalii Hochst,” “Samh,” “Opophytum forsskalii,” “Mesembryanthemum forsskalii,” or “M. forsskalii.”

Selection criteria and quality assessment

This is the first review of research on M. forskalii, noting a recent increase in publications, with over 30 studies covering medical, chemical, botanical, and nutritional aspects, as well as traditional uses. The main research questions focused on the ethnobotanical, botanical, pharmacological, phytochemical aspects, and nutritional value of the samh plant. The systematic review included all relevant publications to capture the plant’s potential benefits. The selection process involved multiple steps, starting with the primary screening of records by two independent reviewers (WA and SM) based on specific keywords. Exclusion criteria included studies not focused on the plant, those lacking full text, and publications before 1994.

Search results

The PRISMA flowchart (Page et al., 2021) was used to conduct the systematic review as displayed in Figure 2, and the results of the search from the various sources, with the number (n) in parenthesis, were as follows: (a) electronic databases: Web of Science (n = 74), PubMed (n = 59), and EBSCO (n = 37), and (b) manual search (n = 14, comprising eight articles and six books). Following the removal of duplicate records (n = 161) and after the screening, titles and abstracts that were not related to M. forsskalii were excluded. In all, a total of 31 records retrieved were relevant to the keywords of the study. After screening, one congress paper was excluded due to similarity. The remaining 30 records included 24 original articles and 6 books on botany, climate, and traditional usage.

Research questions

The main research questions focused on the ethnobotanical, botanical, pharmacological, phytochemical aspects, and nutritional value of the samh plant, leading to secondary questions (Supplementary Figure 1).

Aspects of geographical, historical origins, and climatic requirements of Mesembryanthemum forsskalei Hochst. ex Boiss

The names, climate requirements, and botanical traits of Mesembryanthemum forskahlii Hochst. ex Boiss are detailed in Supplementary Table 1. This annual plant thrives on limestone plains (Al-Jassir et al., 1995b; Al-Shrari, 2019; Ghazanfar, 1994; Mandaville, 2013) and is found in several Arabian countries, including Egypt, Palestine, Jordan, Bahrain, Kuwait, Qatar, and Yemen, with a significant presence in Saudi Arabia (Batanouny, 2000; Ghazanfar, 1994; Mandaville, 2013; Showdrei, 1999). It grows wildly in the Bassita region of Aljouf province, Saudi Arabia (Supplementary Figure 2). The name “Bassita” reflects its growth on spacious, flat terrain with small rocks (Al-Shrari, 2019). In Arabic, M. forskalii is known as samh, meaning generous or tolerant, and hurr, meaning noble or genuine (Mandaville, 2004). This succulent plant tolerates severe desert conditions, including high temperatures and saline soil (Al-Jassir et al., 1995b). Germination occurs in mid-November while flowering and fruiting occur from March to May (Ghazanfar, 1994). Historically, after collecting capsules and extracting seeds, they were preserved for shortages. The collection process involved pounding the plants to loosen the capsules (Mandaville, 2004), gathering them into heaps, and transporting them to a miswal. Seeds were immersed in water, dried, and sieved to remove stones (Mandaville, 2004). Then, the seeds are crushed using a hand mill made of rock (Al-Shrari, 2019; Mandaville, 2004). Currently, custom-built machines are used for harvesting, followed by sieving and grinding with modern machinery (Al-Khaldi, 2019).

Classification and reports of compounds in M. forskalii

Compounds were categorised by chemical structure using the PubChem Database (Kim et al., 2019), employing the “KEGG Phytochemical Compounds” guide or the “MeSH tree” classification when necessary. Unidentified chemicals were classified based on authors’ criteria, with unclassifiable ones in an “other compounds” group. Each compound was tagged with a “PubChem Single Compound Accession Identifier” (CID) when feasible, and quantitative measurements were organised by concentration. Original units were harmonised for uniformity across studies, converting to % or mg/100 g.

As shown in Figure 3A, publications on the samh plant increased over time, peaking in 2020–2024 at 39%. The rise in publications on the samh plant over time might be due to the large increase in research efforts, especially in health and allied sectors, sparked by the coronavirus disease (COVID-19) pandemic. Poor dietary habits, high sugar intake, and low-fibre diets impair health and immunity, and raise the risk of obesity, inflammation, and severe COVID-19 outcomes, as well as associated comorbidities (Bold et al., 2020; Mirzaie et al., 2020; Varzakas & Smaoui, 2024). Moreover, including various nutrient-dense foods derived from traditional and local plants with unique nutritional properties in diets is crucial as dietary diversity becomes more important due to changes in global dietary patterns. In addition, there are efforts to provide scientific support for traditional claims related to the benefits of plants in nutrition and medicine to validate their application in customary medicine and diets (Varzakas & Smaoui, 2024). In Figure 3B, 83.33% of publications focused on samh seeds, while 16.67% addressed aerial parts; only one study each covered fruits, flowers, or essential oils, with no studies on stalks, leaves, or roots. Figure 3C shows that 21 articles primarily used the name Mesembryanthemum forskahlii, while Opophytum forskahlii appeared in three. Additionally, 58.33% (14 of 24) reported chemical compound concentrations, 12.5% (3 articles) identified compounds qualitatively, and 29.17% did not report any (Figure 3D). Regarding plant origin, 15 of 21 studies (71.42%) under M. forskalii mentioned it, while six did not; two studies on O. forskalii defined the origin, with one lacking source details (Supplementary Figure 3).

This systematic review identified 77 bioactive components in the samh plant through qualitative analysis across three studies (Supplementary Tables 2 and 3). As summarised in Supplementary Figure 4, the predominant category was flavonoids and derivatives (24.67%), followed by glucosinolates (19.48%) and various other compounds. Variations in the presence and concentration of phytochemicals among different studies can result from differences in sample origin, extraction methods, and analytical techniques. These discrepancies underscore the impact of geographical factors, including soil and climate, on phytochemical composition (Mansinhos et al., 2024). Furthermore, distinct metabolic pathways in different plant parts contribute to their unique chemical profiles (Maeda & Fernie, 2021).

For instance, Foudah et al. (2022) extracted aerial parts of M. forskalii using 70% ethanol and analysed them via LC–MS, while Hamed et al. (2016) used seeds from a different region, employing 80% methanol for extraction and HPLC-ESI-IT-MS for analysis. Aabed & Mohammed (2021) prepared an aqueous extract of unspecified origin seeds, heating the mixture before gas chromatography–mass spectrometry analysis. The drying process can affect compound stability, while the effectiveness of extraction is influenced by grinding and particle size (Senawong et al., 2023). The polarity of compounds and their affinity for solvents can also result in variations in extraction outcomes (Kumar et al., 2023). Extraction time is vital; shorter durations yield fewer compounds, while longer times extract more chemicals (Senawong et al., 2023). Filtration impacts purity, necessitating advanced techniques for thorough phytochemical analysis and accurate quantification.

Chemical diversity of compounds from M. forskalii plant: A quantitative evaluation of several studies

The distribution of compounds assessed in 14 studies on various parts of the samh plant is summarised in Figure 4, highlighting the diversity and complexity of its phytochemicals. Some compounds appeared in multiple publications, so the reported total in each chemical class may not reflect unique compounds. Amino acids were the most prevalent, followed by fatty acids, phenolics, minerals, flavonoids, carboxylic acids, proteins, fats, and other compounds.

Analysis of the proximate composition and nutritional characteristics of samh

The nutritional components of M. forskalii are listed in Supplementary Table 2 emphasising the seeds and flour. Acid detergent fibre (ADF) assesses indigestible components, which affects digestibility and energy, whereas neutral detergent fibre (NDF) indicates total fibre, which influences food intake (Wang et al., 2021). The ADF is critical for determining the energy content and digestibility of animal diets, whereas NDF is critical for controlling feed intake and guaranteeing optimal rumen function (Stypinski et al., 2024). Only one study reported 20%–35% contents in fruits and seeds of samh. Due to the qualities of NDF and ADF, samh may be put forward as a potentially useful feed resource that merits investigation and careful consideration in livestock diets to maximise animal health and performance. More research should be carried out to investigate the nutritional advantages of samh in different animal species, including its effect on growth performance, milk production, and general health. For animal feeding regimens to be effective and balanced, both measures are necessary. Mesembryanthemum forskalii (samh) offers valuable nutritional benefits for livestock, enhancing digestibility and energy, which improves animal health and food quality for humans. Its incorporation into sustainable feeding practices and potential as a source of functional foods highlights its significance in promoting both animal and human nutrition. By enhancing digestibility and energy, samh can improve animal health and the quality of food for human consumption. Its integration into sustainable feeding practices and potential as a source of functional foods underscores its importance in advancing both animal and human nutrition.

The ash content of samh exhibited variation between studies. The highest levels were found in seeds and flour from Al-Jafer, Jordan (Awabdeh et al., 2022), whereas some studies reported lower ash contents, indicating potential methodological inconsistencies or lower mineral levels. Ash content measurement is essential for assessing the nutritional value and mineral makeup of food. It improves research comparability, reveals deviations from agricultural methods, and guarantees quality control. The nutritional potential of plants such as Mesembryanthemum forskahlii is supported by this investigation, which encourages their usage as beneficial food sources and enhances dietary recommendations.

The carbohydrate content of the samh plant was analysed in 7 of 13 studies, with six reporting values between 52.3% and 66.63% from Al-Jouf, Saudi Arabia, attributed to regional similarities and standardised AOAC analytical methods. Despite different methods, i.e., the phenol-sulphuric acid method, Ahmed et al. (2020) found comparable carbohydrate percentages, while Abdel-Farid et al. (2016) reported only 20.9%–22.61% carbohydrates using Dreywood’s anthrone reagent method. The discrepancies underscore the need for standardisation in nutritional research, as varying procedures can lead to significant differences in results. Standardising analytical methods using AOAC protocols will improve nutritional data accuracy and support informed dietary recommendations regarding the plant’s value and culinary uses. The high carbohydrate content of the samh plant could potentially be utilised to develop energy-dense functional foods, such as health energy bars and meal replacements, catering to health-conscious consumers and athletes.

Samh seeds have modest fat content, with variations influenced by processing, genetics, environmental factors, and analytical methods. Their fibre content ranges from 4.36% to 10.62%, and moisture levels typically fall between 3.09% and 11.5%. These characteristics present opportunities for transforming samh seeds into nutritious flour and health products. Best practices for processing include maintaining optimal moisture levels of 10%–11% (Ellis et al., 1991) to ensure seed longevity, using careful milling techniques to retain fat content, and consistently monitoring environmental conditions to enhance the quality and nutritional value of samh seeds in functional food applications.

In terms of protein content, similar protein levels were found in fruits and seeds. Shoots had a lower protein content, likely due to being younger and less nutrient-dense compared with the more mature seeds and fruits, which are specialised for nutrient storage. Nutritional composition is influenced by growing conditions (Elbasiouny et al., 2022). Alruqaie and Al-Ghamidi (2015) reported 24.4% crude protein in raw seeds and 19.5% in low-fat flour, indicating processing may reduce protein content. Raw flour may be more suitable for direct consumption. Samh plant could serve as a valuable source of plant-based protein in energy bars and nutritious snacks, providing essential amino acids for a balanced diet. To enhance the nutritional profile, it is important to ensure optimal growing conditions and to process the seeds carefully to minimise protein loss, maximising their health benefits for vegetarian diets.

Amino acids and fatty acids profiles

Five studies have identified a total of 18 amino acids in samh seeds (Table 1) with their percentages ranging from 71.63% to 73.26%. Notably, nonessential amino acids such as glycine, aspartic acid, arginine, and glutamic acid constitute a significant portion, accounting for 60.33%–64.70% of the nonessential amino acid content. One study reported an even higher concentration of 84.82% in Saudi M. forskalii seeds (Abdel-Hamid et al., 2021). Additionally, proline levels were notably high in Egyptian seeds, contributing 85.32% to the nonessential amino acids. In terms of essential amino acids, histidine, leucine, and phenylalanine made up 49.63%–59.59% of the total. Conversely, a study by Mohammed et al. (2023) reported that nonessential amino acids comprised only 11.55%, with aspartic acid, glutamic acid, glycine, and arginine at 4.52%. Essential amino acids, on the other hand, accounted for 88.45%, with threonine, valine, phenylalanine, and histidine representing 80.90%. The variation in amino acid concentrations is influenced by seed protein content and the methodologies employed in the analysis. Differences in detection methods, particularly those sensitive to acid hydrolysis, can lead to degradation or underrepresentation of certain amino acids (Rutherfurd & Moughan, 2012). To preserve amino acid integrity, alternative hydrolytic techniques such as enzymatic hydrolysis are recommended (Meinlschmidt et al., 2016). For instance, Al-Jassir et al. (1995b) utilised 6 N HCl for hydrolysis, while Najib and Al-Khateeb (2004) employed high-temperature HCl hydrolysis with chemical modifications for HPLC detection. Alderaywsh et al. (2019) applied performic acid oxidation followed by alkaline hydrolysis. These methodological differences can result in inconsistencies in amino acid profiles, underscoring the necessity for standardised analytical techniques.

In terms of fatty acid profile, samh reveals a predominance of unsaturated fatty acids over saturated ones, as evidenced by multiple studies focusing on seeds, herbs, and flowers (Table 2). Notably, linoleic acid is consistently identified as the most abundant unsaturated fatty acid, with concentrations reported at two studies (Ahmed et al., 2020; Al-Jassir et al., 1995b). Additionally, linolelaidic acid was found to be predominant in oil seeds at 54.24% (Mohammed et al., 2023). In flowers, linoleic, linolenic, and oleic acids collectively accounted for 73.30% of the total fatty acids (Dababneh et al., 2017) (Table 3). Seeds serve as a rich source of health-promoting fatty acids, which are essential for energy storage and reproduction, storing significant lipid reserves primarily as unsaturated fatty acids (Linder, 2000). On the other hand, flowers are primarily geared for reproductive function, with a biochemical makeup optimised to attract pollinators, resulting in reduced fatty acid levels (Muhlemann et al., 2014). This distinction underscores the nutritional value of seeds and their potential health benefits (Nemzer & Al-Taher, 2023).

Phenolic and flavonoid compounds

The samh plant displays variations in phenolics and flavonoid concentrations across its different parts (Table 4). Fruits have the highest levels, followed by shoots and seeds. These higher phenolic concentrations in fruits are associated with attracting pollinators and protecting against pests, while shoots may benefit from floral contributions. Variations in phenolic content can be influenced by genetic factors and the timing of sample collection (Abdel-Farid et al., 2016; Al-Shrari, 2019). Tannin levels in seeds also vary, with distinct concentrations reported in different studies, indicating potential influences from plant species, environmental conditions, or methodologies (Alderaywsh et al., 2019; Mohammed et al., 2023). In flowers, ferulic acid is the most abundant phenolic acid, followed by p-hydroxybenzoic and vanillic acids, suggesting greater metabolic activity compared with herbs (Dababneh et al., 2017; Kaisoon et al., 2011). The higher concentrations of phenolic acids in seeds provide chemical defence during germination and growth, enhancing their nutritional value and health benefits, thereby underscoring the samh plant’s potential in herbal medicine (Rehman et al., 2012). Moreover, phenolic compounds such as tannins, caffeic acid, catechol, and ferulic acid are recognised for their health benefits, including anti-inflammatory, antioxidant, and anticancer properties. Caffeic acid enhances cognitive function and protects against cardiovascular diseases, while catechol combats oxidative stress, potentially reducing chronic disease risk. Ferulic acid aids in managing obesity and diabetes, and gallic acid offers antioxidant, antimicrobial, and anti-inflammatory benefits. Other phenolic compounds, including naringenin, p-coumaric acid, and protocatechuic, further contribute to health benefits, including cancer prevention and metabolic support. Collectively, these findings highlight the significance of the samh plant and its phenolic compounds in promoting health and their potential applications in herbal medicine (Rashmi & Negi, 2020; Sharma et al., 2021).

Regarding flavonoids, the studies provided detailed profiles of flavonoids in the seeds of the samh plant, revealing significant concentrations. The shoots had the highest flavonoid content, followed by fruits and seeds (Abdel-Farid et al., 2016). Catechin was the most abundant flavonoid in seeds followed by kaempferol and isorhamnetin (Ahmed et al., 2020; Mohammed et al., 2023). The findings suggest that these plant parts could serve as valuable sources of bioactive compounds. Given the established antioxidant and anti-inflammatory properties of flavonoids (Zhang et al., 2011), further exploration of the samh plant’s flavonoid composition could enhance our understanding of its potential health benefits and promote its use in functional foods and nutraceuticals. This underscores the importance of incorporating such plant-based sources into diets to leverage their health-promoting properties.

Carboxylic acid profiles

M. forskalii shows varying carboxylic acid levels across its sections (Supplementary Table 4), with a comprehensive study by Dababneh et al. (2017) identifying these acids but lacking details on collection conditions. Carboxylic acids were extracted from plant material using methylene chloride and analysed via gas chromatography–mass spectrometry. Herbs had higher oxalic and citric acid levels, whereas flowers had more malic, levulinic, and succinic acids. The study did not assess carboxylic acids in seeds, highlighting the need for further research on their nutritional and medicinal values.

Minerals and other compounds of samh

The mineral composition of samh seeds demonstrates notable concentrations of essential minerals (Supplementary Table 5). Studies indicate the presence of calcium, magnesium, phosphorus, potassium, and sodium, all of which are vital for various physiological functions. Additionally, trace minerals were identified in slight concentrations, further emphasising the diverse mineral profile of these seeds. This diversity underscores the significance of growth conditions in nutritional evaluations and the potential health benefits associated with consuming samh seeds.

On the other hand, various compounds in samh seeds were reported including glycoside, which varied significantly, with shoots containing the highest levels, followed by seeds and fruits (Supplementary Table 6). Plants focus energy on shoots and seeds for protection, whereas fruits, being in the final reproductive stage, require less energy for defence. The shoot of a plant is normally in an active developmental phase, which results in increased quantities of bioactive chemicals such as glycosides, which protect the plant from environmental stresses and improve its nutritional profile (Boeckler et al., 2011). Phytic acid, an antinutritional component, was found at concentrations of 88 mg/100 g DM in Alderaywsh et al. (2019) and 64 mg/100 g DM in Mohammed et al. (2023). These levels can affect mineral bioavailability in human diets (Manzoor et al., 2024). While phytic acid may seem harmful, it can help regulate calcium metabolism and reduce the risk of kidney stone formation by preventing calcium oxalate crystallisation (Ekramzadeh et al., 2024; Li et al., 2024). To mitigate its antinutritional effects and enhance mineral bioavailability, food processing methods like sprouting, fermentation, and soaking are recommended (Li et al., 2024). Heat-based procedures such as baking and roasting also help to reduce phytic acid concentration in seeds (Sherin et al., 2024). Combining phytic acid-rich foods with vitamin C can also improve mineral absorption (Subroto et al., 2021). Implementing these strategies may enhance the nutritional value of samh seeds, particularly for populations at risk of mineral deficiencies. On the other hand, the restricted data on the ammonium ion’s detection in samh seeds (1639.3 mg/100 g protein) raise questions about its safety for human consumption. More research is required to duplicate results, determine ammonium toxicity, and analyse the nutritional profile to confirm safety. To fully understand the safety of samh seeds, human trials and comparisons with safety standards will be used to ascertain the potential health effects of consuming them. A study by Bilel et al. (2020) found that essential oil from samh seeds contains high steroid concentrations, with beta-sitosterol as the main component at 33.05%, known for its cholesterol-lowering and anti-inflammatory effects (Rashed, 2020). Alpha-amyrin, at 7.32%, is recognised for skin health and anti-inflammatory properties (Okoye et al. 2014). The oil also contained beneficial long-chain alkanes, enhancing its applications in cosmetics, food, and pharmaceuticals (Bhavaniramya et al., 2023).

Effects of processing methods on the physicochemical properties, quality, and nutritional profile of samh seeds

The physicochemical properties of different samh seed samples were analysed, revealing that fermented seeds exhibited superior characteristics compared with raw and germinated seeds (Figure 5). Fermented seeds had a bulk density of 0.813 g/cm³ and swelling power of 2.64 g/g, surpassing raw seeds (0.795 g/cm³, 2.33 g/g) and germinated seeds (0.798 g/cm³, 2.49 g/g). This enhancement facilitates better nutrient and flavour release, attributed to protein structure modifications and starch molecular vibrations (Elkhalifa & Bernhardt 2013). Additionally, fermented seeds were more acidic (pH = 4.43) and contained higher lactic acid levels (2.27 g/100 g) than raw (0.30 g/100 g) and germinated seeds (0.45 g/100 g), improving flavour and preservation (Gong et al., 2022). Functional qualities showed that fermented seeds had higher water (32.18 ml/100 g) and oil absorption (26.83 ml/100 g) compared with raw seeds, while germinated seeds also demonstrated good absorption (30.93 ml/100 g water, 25.23 ml/100 g oil) due to macromolecule breakdown (Azeez et al., 2022). Fermented seeds achieved a foaming capacity of 24.06%, with protein isolate exhibiting excellent foam stability (95%). Colour analysis indicated that yellowness increased from 9.82 in raw seeds to 13.34 in fermented seeds, with brightness rising by 9.1%, while the red hue decreased by 1.2%, suggesting fermentation enhances yellowness due to pigment deterioration (Mohammed et al., 2023). Germinated seeds showed increased yellowness (13.03) and redness (8.61), indicating colour profile alterations through pigment oxidation (Sharma & Sharma 2022). Pigments may concentrate due to migration and subsequent drying and milling (Mohammed et al., 2023). These findings highlight the significant impact of processing methods on the aesthetic qualities of samh seeds, which can influence consumer acceptance in food manufacturing.

Antioxidant levels

Processing methods significantly enhance the antioxidant properties, total phenolic content (TPC), and total flavonoid content (TFC) of samh seeds (Supplementary Table 7). Fermented seeds exhibited a TPC of 243 mg GAE/100 g DM (100.8% increase), while germinated seeds had a TPC of 172 mg GAE/100 g DM (42.15% increase). TFC increased to 256 mg CE/100 g DM in fermented seeds (60% increase) and 369 mg CE/100 g DM in germinated seeds (130.63% increase). Antioxidant activity improved, with DPPH inhibition rising from 0.65% in raw seeds to 78.39% in fermented seeds, enhancing nutritional profiles and reducing antinutritional factors (Mohammed et al., 2023). Roasted seeds also exhibited higher antioxidant activity due to increased phenolic and flavonoid levels (Ahmed et al., 2020). Fermentation enhances TPC and TFC by breaking down complex molecules, improving bioavailability (Sadh et al., 2022), while germination activates pathways that synthesise new antioxidants (Zhang et al., 2015). Roasting improves the accessibility of beneficial chemicals via the Maillard reaction (Zou et al., 2018). Overall, these processing methods significantly improve the nutritional and antioxidant content of samh seeds, suggesting their potential in functional foods and nutraceuticals for oxidative stress-related diseases.

Glycemic index and microbial activity

One investigation (Mohammed et al., 2023) determined the effects of fermentation and germination on seed qualities, summarised in Supplementary Table 8. Data comparison showed significant variations due to processing. Overall, fermentation and germination altered the nutritional and microbial profiles of the seeds through biological and chemical processes (Chiu & Sung 2014; Nkhata et al., 2018). Bacteria and yeast break down carbohydrates in seeds, producing organic acids, alcohols, and gases, enhancing total solids by concentrating remaining simpler sugars (Nkhata et al., 2018). Fermentation alters carbohydrate structure, reducing digestibility and lowering the glycemic index by delaying glucose release. Bioactive substances from fermentation and germination likely modulate glucose metabolism, contributing to this effect (Gong et al., 2022). Germination involves water absorption, activating enzymes that break down stored nutrients like starches and proteins into simpler forms for plant growth (Joshi, 2018). This nutrient mobilisation decreases total solids as seeds deplete reserves plant (Joshi, 2018; Nkhata et al., 2018). Germination also alters carbohydrate composition, increasing soluble fibres and resistant starches, thus reducing glycemic index (Nkhata et al., 2018). Moisture and warmth during germination promote beneficial bacteria growth, increasing yeasts and moulds, highlighting a gap in understanding processing effects on samh samples.

Phenolic compounds and the macronutrient value of samh seeds

Fermented and germinated samh seeds show notable differences from raw seeds in nutritional characteristics and chemical composition. As summarised in Supplementary Table 9, germination led to significant increases in beneficial phenolic compounds, such as gallic acid and catechin, enhancing the seeds’ antioxidant capacity. In contrast, fermented seeds showed modest increases in phenolic compounds but a significant rise in rutin trihydrate, indicating selective amplification during fermentation (Mohammed et al., 2023). Macronutrient analysis revealed that fermented seeds had slight decreases in ash and carbohydrate contents, along with reduced moisture. Germinated seeds exhibited more pronounced reductions in carbohydrates and moisture due to soaking and sprouting. Fermented seeds had higher fat content, resulting in enhanced energy density as carbohydrates and proteins converted to fats during fermentation, while germinated seeds utilised stored nutrients for growth, leading to lower fat and energy density (Mohammed et al., 2023). Fermented seeds had much lower fibre content than raw seeds, with values half that of germinated seeds’ carbohydrates (Guillamón et al., 2008). Germination increased nutritional bioavailability but decreased fibre levels through hydrolysis and leaching (Li et al., 2020). Overall, germination boosts a wider range of antioxidants, while fermentation enhances specific compounds, suggesting dietary choices should consider these differences.

Furthermore, a complex relationship was found between roasting and seed phenolic composition, with increases in levels of beneficial compounds such as gallic acid and rutin trihydrate and decreases in levels of protocatechuic acid and caffeic acid. This highlights the dual effect of roasting on seed composition. Alderaywsh et al. (2019) investigated the nutritional properties of roasted, cooked, and baked flour derived from the same raw materials. Roasted flour had the highest ash level due to moisture loss, but cooked flour had less ash due to mineral leaching. Likewise, roasted flour had the lowest moisture level, but baked flour had more moisture from additional water. The fat level of roasted flour was slightly increased, but cooked and baked flour exhibited significant reductions. The highest protein concentration was found in roasted flour. This might be due to starch gelatinisation and the breakdown of complex carbohydrates into simpler sugars, which improved digestibility. However, baked flour showed a decrease that may be due to denaturation. Carbohydrate content was increased in roasted and cooked flour but was markedly decreased in baked flour due to moisture loss and chemical processes that degrade carbohydrates. These data highlight the importance of processing methods in the determination of the nutritional properties of flour products (Alderaywsh et al., 2019).

Amino acids, fatty acids, and minerals

Some studies examined the amino acid composition and in vitro protein digestibility of various processed forms of samh seeds, including fermented and germinated seeds, as well as different flours (roasted, boiled, and baked). As shown in Supplementary Figure 5a, germination significantly increased protein digestibility to 51.04% and elevated levels of essential and nonessential amino acids compared with raw and fermented samples. This enhancement is linked to decreased antinutritional factors, increased enzyme accessibility, and protein hydrolysis (Maetens et al., 2017; Mohammed et al., 2023; Wongsiri et al., 2015). Fermentation improved protein digestibility by 57.28% and increased essential amino acids, except for histidine and lysine, due to amino acid liberation by lactic acid bacteria (Mohammed et al., 2023; Mohapatra et al., 2019). Roasted flour showed a digestibility of 76.7%, with increases in glutamic acid and modest gains in other amino acids, while cooking yielded the highest digestibility at 84.8% (Alderaywsh et al., 2019). Different cooking methods affected amino acid profiles, indicating the importance of cooking techniques in enhancing nutritional quality.

Supplementary Figure 5b illustrates that processing methods significantly altered fatty acid content. Roasted seeds had a remarkable drop in palmitic acid and linolenic but a 155.55% and 242.86% increase in behenic acid and linolelaidic acids, respectively (Ahmed et al., 2020). Fermented seeds contained more palmitic (5.52%) and linolelaidic acid (16.00%) than untreated seeds, while germination reduced palmitic acid (3.36%) and increased stearic acid (11.79%) (Mohammed et al., 2023). These changes suggest that lipase and phospholipase activities during processing influenced fatty acid composition. Overall, samh seeds are rich in unsaturated fatty acids, with fermentation reducing and germination enhancing their nutritional value (Nemzer & Al-Taher 2023).

Fermented seeds showed elevated levels of essential minerals (Supplementary Figure 5c), including calcium, magnesium, potassium, sodium, and phosphorus, ranging from 4.72% to 19.11%. In contrast, copper levels decreased by 45.45%, while iron levels increased by 26.55%. These changes are attributed to alterations in the seed matrix, microbial consumption of minerals, breakdown of antinutritional components, and the release of bound minerals into soluble forms during fermentation (Anaemene & Fadupin 2022; Azeez et al., 2022; Chinma et al., 2022). Germinated seeds exhibited lower calcium and magnesium levels, while potassium increased significantly by 35.46% (Mohammed et al., 2023). This suggests that metabolic activities during steeping promote potassium accumulation, with the loss of other minerals likely due to their role as enzyme cofactors (Bhinder et al., 2021). Roasted seeds experienced significant mineral changes: potassium rose by 386.56%, magnesium fell by 35.67%, and sodium increased by 728.81%, likely due to moisture loss and thermal degradation of antinutritional components (Ahmed et al., 2020). These findings underscore the critical impact of processing techniques on the nutrient profiles of seeds, with variations depending on seed type and processing conditions.

In vitro pharmacological effects of M. forskohlalii

Antimicrobial activity

The antimicrobial potential of M. forskalii seed extract was first explored by Al-Jassir et al. (1995b), who tested it against 20 microorganisms, including various bacterial and fungal species. At a concentration of 1 g/ml, the extract showed no antimicrobial activity. This lack of effect was corroborated by Foudah et al. (2022), who found no activity at 10 mg/ml against similar strains. However, silver nanoparticle (AgNP) derivatives of the seed extract demonstrated significant antibacterial properties, with inhibition zones ranging from 10 to 29.3 mm. The AgNPs exhibited the highest efficacy against Pseudomonas spp. and Escherichia coli, while showing reduced effectiveness against gram-positive bacteria due to challenges in penetrating their cell walls (Aabed & Mohammed, 2021). Additionally, the seed oil extract from M. forskalii displayed antifungal activity against 11 fungal species isolated from the hair of children, achieving an 88% inhibition rate against Penicillium chrysogenium and Aspergillus fumigatus, and 85% against Aspergillus flavus. These findings suggest that M. forskalii seed oil could be a viable option for treating fungal infections (Bilel et al., 2020).

Antioxidant and anticancer activity

In vitro studies indicated M. forskalii seed oil had significant antioxidant activity (IC₅₀ of 3.43 ± 0.19 mg/ml), attributed to concentrated phytochemicals (Bilel et al., 2020). Phenolics and glucosinolates from samh wheat effectively reduced lipid and protein damage in human plasma (Hamed et al., 2016). All tested doses inhibited lipid peroxidation induced by H₂O₂, outperforming Aronia melanocarpa extracts. Regarding cancer treatment, no reports in the literature have demonstrated the anticancer activity of the M. forsskalii plant or any part of the plant. However, using an MTT assay, only one report revealed that AgNPs of M. forsskalii seed powder exerted cytotoxicity against colon carcinoma cells (Lovo cell lines). The cells were treated with varying concentrations of the AgNPs (100–6.25 μg/ml) for 48 hr. The growth of the LoVo cancer cell line was inhibited in a dose-dependent manner, with a half-maximal inhibitory concentration (IC₅₀) value of 28.32 μg/ml (Bilel et al., 2020). More studies are needed on M. forskalii’s anticancer effects, focusing on its parts and bioactive components, mechanisms of action against various cancer cell lines, and potential synergistic effects with other treatments.

In vivo pharmacological effects of M. forskalii

Antidiabetic activities

In the study by Al-Faris et al. (2010), diabetes was induced in five groups of Wistar Albino rats (n = 6) using STZ. Groups received natural or high-fat diets with 10% or 15% samh seeds. Liver enzyme activities (AST, ALP) showed nonsignificant changes. Groups 1 and 2 had insignificant cholesterol declines, while Groups 3 and 4 had marked elevations. Triglyceride levels were significantly higher in Groups 3 and 4 (p < .05). The study indicated that samh seeds without cholesterol regulated lipid metabolism but lacked nondiabetic controls. In the study by Al Faris et al. (2011), a negative control was included, and a 5% samh seed diet was used. After 6 weeks, significant decreases in cholesterol (40%), triglycerides (46%), and HDL-C (31%) were observed, indicating potential hypoglycemic and antihyperlipidemic benefits, with no marked changes in blood glucose.

Antiulcerogenic effect

Foudah et al. (2022) investigated the effectiveness of samh plant aerial parts in treating gastric lesions. Preadministration of samh extract at 400 mg/kg significantly reduced the ulcer index from 37.33% to 28.33% and the intraluminal bleeding score from 3.5 to 1.6. The 200 mg/kg dose showed limited preventive impact. The extract was also protected against gastric ulcers induced by ethanol (80%), NaOH (0.2 mol/L), and NaCl (25%), preventing severe lesions. MDA levels increased from 0.5 to 5.8 nmol/g in untreated groups but dropped to 2.34 nmol/g after samh pretreatment, indicating antioxidant properties. Histological analysis confirmed gastroprotective effects. Further research is needed on dose variations and the long-term safety of samh extracts for therapeutic use in gastric damage models.

Hepatoprotective activity

Mahalel et al. (2023) found that daily administration of 100 mg/kg of samh fruit extract for 15 days in a CCl4 mouse model normalised weights and improved liver function by restoring AST and ALT levels, downregulating P53, and upregulating Bcl-2 and the histological analysis confirmed these effects. However, a 500 mg/kg dose showed no benefits against CCl4 toxicity and slightly harmed liver enzymes, indicating a dose-dependent response.

Toxicological aspects M. forskahlii

Although studies have shown the nutritional and therapeutic benefits of M. forskahlii, they focused more on the benefits of the fruit extracts and seeds than on carefully examining any negative effects or safety profiles. The toxicology of the samh plant has not been extensively studied for various reasons. First, researchers prioritise studies that demonstrate favourable results since the increased interest in functional foods and traditional treatments frequently prioritises health advantages over safety concerns. This tendency can lead to a lack of awareness regarding the possible negative consequences of ingesting these plants, especially for people who might utilise them as traditional remedies or dietary supplements. Second, toxicological research necessitates exacting procedures and long-term evaluations, which can be costly and time-consuming. Funding or sponsorship for such studies may be difficult to come by for researchers, particularly if the original goal is to examine health benefits. Finally, there is a widespread belief that natural goods are safe by nature, especially those that have been used traditionally. This idea may cause people to become complacent about the necessity of comprehensive toxicological analyses.

Limitations of studies on M. forskalii

Research on M. forskahlii is limited by a predominant focus on its seeds, which leads to the neglect of other potentially beneficial parts of the plant. This limitation is further compounded by geographical variability in soil and climate, which can significantly affect the nutritional composition of the plant. Additionally, variations in sample preparation can alter chemical profiles, complicating the interpretation of results. The absence of clinical trials restricts the ability to make robust health claims, emphasising the need for comprehensive studies that encompass all parts of the plant. Although there is a body of literature highlighting the potential of M. forskahlii for health improvement, particularly in disease treatment, the scant research on other plant parts indicates that the full range of advantages has not been thoroughly explored. Consequently, there is a critical need for comprehensive research on the safety features, toxicological aspects and hepatoprotective benefits of M. forskahlii, particularly concerning dose optimisation.

Conclusion and recommendations

Mesembryanthemum forskahlii Hochst. ex Boiss. (samh) has significant bioactive and nutritional potential, with seeds rich in proteins, essential fatty acids, and phytochemicals. While studies emphasise its health benefits for diabetes and hyperlipidemia, research on other plant parts is limited. Future studies should focus on investigating the bioactive compounds present in seed and in other various parts of M. forskahlii to fully understand the therapeutic potential of these phytochemicals in managing liver damage and related health issues. Thorough toxicological investigations are essential to ensure the safe use of M. forskahlii, and this area should be prioritised in future research to provide a balanced understanding of the plant’s potential hazards and health benefits. Additionally, it is recommended that research explore modern culinary applications of M. forskahlii in both contemporary and traditional diets, as well as the effects of different sample treatments on its nutritional value, to facilitate its integration into regular meals. Finally, this plant provides a unique opportunity for better health outcomes by supporting sustainable food systems, as interest in plant-based diets and functional foods grows globally. To ensure that native plants like samh and others are fully used for nutrition and health, future research should work to close the knowledge gap between conventional usage and scientific validation. The authors encourage the sustainable use of samh and related plants through promotion of collaboration among researchers, nutritionists, and local populations. This will ultimately improve dietary diversity and public health.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Author contributions

Waad A. Al-Otaibi (Conceptualisation [equal], Data curation [equal], Formal analysis [equal], Funding acquisition [equal], Investigation [equal], Methodology [equal], Project administration [equal], Resources [equal], Software [equal], Supervision [equal], Validation [equal], Visualisation [equal], Writing—original draft [equal], Writing—review & editing [equal]) and Sahar M. Al-Motwaa (Conceptualisation [equal], Data curation [equal], Formal analysis [equal], Funding acquisition [equal], Investigation [equal], Methodology [equal], Resources [equal], Software [equal], Validation [equal], Visualisation [equal], Writing—original draft [equal], Writing—review & editing [equal]).

Funding

No funding was received.

Conflicts of interest

The authors report there are no competing interests to declare.

Acknowledgements

The authors would like to thank the Deanship of Scientific Research at Shaqra University for supporting this work.

References

Author notes