A new steroidal saponin from the seeds of Allium tuberosum

Chemical Constituents, Biological Activities, and Proposed Biosynthetic Pathways of Steroidal Saponins from Healthy Nutritious Vegetable-Allium

Allium is a common functional vegetable with edible and medicinal value. Allium plants have a special spicy taste, so they are often used as food and seasoning in people's diets. As a functional food, Allium also has abundant biological activities, some of which are used as drugs to treat diseases. By consuming Allium on a daily basis, people can receive active compounds of natural origin, thereby improving their health status and reducing the likelihood of disease. Steroidal saponins are important secondary metabolites of Allium, which are formed by the steroidal aglycone group and sugar. Steroidal saponins have various physiological activities, such as hypoglycemic, antiplatelet aggregation, anti-inflammatory, antitumor, antimicrobial, and enzyme activity inhibition, which is one of the key reasons why Allium has such significant health benefits. The structural diversity and rich biological activities of steroidal saponins make Allium important plants for both food and medicine. In this paper, the chemical structures, biological activities, and structure-activity relationships of steroidal saponins isolated from Allium are reviewed, and the biosynthetic pathways of some key compounds are proposed as well, to provide a molecular reference basis based on secondary metabolites for the health value of Allium.

Advances in the Biosynthesis and Molecular Evolution of Steroidal Saponins in Plants

Steroidal saponins are an important type of plant-specific metabolite that are essential for plants' responses to biotic and abiotic stresses. Because of their extensive pharmacological activities, steroidal saponins are also important industrial raw materials for the production of steroidal drugs. In recent years, more and more studies have explored the biosynthesis of steroidal saponins in plants, but most of them only focused on the biosynthesis of their molecular skeleton, diosgenin, and their subsequent glycosylation modification mechanism needs to be further studied. In addition, the biosynthetic regulation mechanism of steroidal saponins, their distribution pattern, and their molecular evolution in plants remain unclear. In this review, we summarized and discussed recent studies on the biosynthesis, molecular regulation, and function of steroidal saponins. Finally, we also reviewed the distribution and molecular evolution of steroidal saponins in plants. The elucidation of the biosynthesis, regulation, and molecular evolutionary mechanisms of steroidal saponins is crucial to provide new insights and references for studying their distribution, diversity, and evolutionary history in plants. Furthermore, a deeper understanding of steroidal saponin biosynthesis will contribute to their industrial production and pharmacological applications.

Nutritional values and phytochemical analysis of Allium calocephalum Wendelbo, a valuable endemic wild garlic to Zagros mountains

Wild edible plants provide the local people with food and medicines and are considered one of the natural ecosystem services. These wild edible diets and herbal medicine always reflect local communities' regional identity and their traditional ecological knowledge. In the new global economy, the natural product field has become a central issue for preserving the traditional culture related to nature, particularly in the context of a sustainable environment. This research study aims to determine the nutritional value and phytochemical contents in a wild population of Allium calocephalum. This wild edible garlic, endemic to the Zagros mountains, is overharvested by Kurdish rural people to enhance their food security at a household level and to perpetuate the preservation of their natural heritage. Here, we estimated the total phenols, flavonoids, carbohydrates, protein, fibers, ash, oil yield, and significant mineral content in both leaves and bulbs of A. calocephalum. Phytochemical analyses were conducted at the Faculty of Agricultural Engineering Sciences (University of Duhok) and the environmental directory of Duhok, Kurdistan Region of Iraq, to get an overview of its nutrients and phytochemical values. Interestingly, a high level of phenolic compounds was obtained from bulbs (0.684 mg gallic acid equivalents/g of dry extract, eq.100g-1). The lowest level of phenolic compounds was found in leaves (0.522 mg gallic acid equivalents/g of dry extract, eq.100g-1). Simultaneously, the bulbs extract gave higher content of flavonoid compounds than the leaves extract (6.31 and 4.73 μg quercetin equivalents/g of dry extract, eq.100g-1, respectively, for the bulbs and leaves). The highest dry weight basis of total carbohydrates, energy value (Kcal), oil content, and moisture content were observed in bulbous parts, and the values were 71.75, 408.86 (Kcal), 9.52, and 92.37, respectively. On the other side, the highest dry weight basis of total protein, fibers, and Ash content was observed in shoot parts, and the values were 15.93, 13.89, and 9.32, respectively. The evidence from this research study supports the idea that this Zagrosian endemic wild garlic enhances the food security and the nutrient diet values of the rural Kurdish people. Keywords: Wild garlic; ethnobotany; edible plants; food security; natural resources; herbal medicine.

Recent advances in research on Allium plants: functional ingredients, physiological activities, and applications in agricultural and food sciences

Fruits and vegetables (FVs) have long been a major source of nutrients and dietary phytochemicals with outstanding physiological properties that are essential for protecting humans from chronic diseases. Moreover, the growing demand of consumers for nutritious and healthy foods is greatly promoting the increased intake of FVs. Allium (Alliaceae) is a perennial bulb plant genus of the Liliaceae family. They are customarily utilized as vegetable, medicinal, and ornamental plants and have an important role in agriculture, aquaculture, and the pharmaceutical industry. Allium plants produce abundant secondary metabolites, such as organosulfur compounds, flavonoids, phenols, saponins, alkaloids, and polysaccharides. Accordingly, Allium plants possess a variety of nutritional, biological, and health-promoting properties, including antimicrobial, antioxidant, antitumor, immunoregulatory, antidiabetic, and anti-inflammatory effects. This review aims to highlight the advances in the research on the bioactive components, physiological activities and clinical trials, toxicological assessment for safety, and applications of different Allium plants. It also aims to cover the direction of future research on the Allium genus. This review is expected to provide theoretical reference for the comprehensive development and utilization of Allium plants in the fields of functional foods, medicine, and cosmetics.

Control of Panama disease of banana by intercropping with Chinese chive (Allium tuberosum Rottler): cultivar differences

Panama disease (Fusarium wilt disease) caused by Fusarium oxysporum f. sp. cubense race 4 (FOC) severely threatens banana (Musa spp.) production worldwide. Intercropping of banana with Allium plants has shown a potential to reduce Panama disease. In this study, six cultivars of Chinese chive (Allium tuberosum Rottler) were selected to compare their differences in antifungal activity and active compounds. Three cultivars Duokang Fujiu 11, Fujiuhuang 2, and Duokang Sijiqing with higher levels of antifungal compounds were further used for intercropping with banana in the pots and field to compare their effects on growth and disease incidence of banana.The six cultivars showed significant differences in antifungal activity against FOC mycelia growth in both leaf volatiles and aqueous leachates. The aqueous leachates displayed stronger antifungal activity than the volatiles. FJH cultivar showed the best inhibitory effect among all six cultivars. Contents of three main antifungal compounds dipropyl trisulfide (DPT), dimethyl trisulfide (DMT), and 2-methyl-2-pentenal (MP) in volatiles and aqueous leachates varied considerably among cultivars. Pot and field experiments showed that intercropping with three selected Chinese chive cultivars significantly improved banana vegetative growth, increased photosynthetic characteristics and yield but decreased disease incidence of Panama disease.Our results indicate that intercropping with Chinese chive shows potential to reduce banana Panama disease and selection of appropriate cultivars is vital for effective disease control.

Comprehensive analysis of an uninvestigated wild edible medicinal garlic species from Turkey: Allium macrochaetum Boiss. & Hausskn

The study was aimed to investigate the phenolic compounds of Allium macrochaetum by LC-MS/MS, as well as the antioxidant, antialzheimer, and antimicrobial activities of the extracts, and determination of the essential oil and fatty acid compositions by GC-MS. The results indicate that malic acid and t-caffeic acid are the major compounds in the bulbs. The main components of fatty acids were found to be linolenic (40.72%), oleic (19.79%), and palmitic (18.45%) acids. The allyl disulfide (66.97%) was found as major compound in the essential oil. The ethanol extract of the bulbs exhibited stronger ABTS cation (IC₅₀ : 55.90 ± 1.08 µg/ml) and DPPH free (IC₅₀ : 204.43 ± 2.17 µg/ml) radical scavenging activities than the other extracts. The extract also showed moderate cupric reducing activity with 1.52 absorbance at 100 µg/ml concentration. Only the ethanol extract of the bulbs showed weak inhibition (23.34 ± 0.11%) against butrylcholinesterase enzyme at 200 µg/ml. PRACTICAL APPLICATIONS: Allium macrochaetum is a wild and edible garlic species which grown in Turkey, Iran, Iraqi, and Syria. A. macrochaetum has been used by local people in Turkish folk medicine as an antibiotic, and for the treatment of alopecia. The health benefits and nutritional values of A. macrochaetum were clarified in the first time. Phenolic compounds of A. macrochaetum were detected by LC-MS/MS. The essential oil and fatty acid compositions of A. macrochaetum were identified by GC-MS. Antioxidant, antialzheimer, and antimicrobial activities potential of A. macrochaetum were determined.

Inventory of Toxic Plants in Morocco: An Overview of the Botanical, Biogeography, and Phytochemistry Studies

Since they are natural, plants are wrongly considered nondangerous; therefore people used them in various contexts. Each plant is used alone or in mixture with others, where knowledge and the requirements of preparation and consumption are not mastered. Thus, intoxications due to the use of plants have become more and more frequent. The reports of intoxications made at the Antipoison Center and Pharmacovigilance of Morocco (ACPM) support this finding, since the interrogations suffered by the victims show that the use of plants is practiced irrationally, anarchically, and uncontrollably. Faced by the increase of these cases of poisoning in Morocco, it seemed necessary to investigate the nature of poisonous plants, their monographs, and the chemicals responsible for this toxicity.

In vitro and in vivo aphrodisiac properties of the seed extract from Allium tuberosum on corpus cavernosum smooth muscle relaxation and sexual behavior parameters in male Wistar rats

BACKGROUND

Allium tuberosum is a well-known spice as well as a herb in traditional Chinese medicine, used for increasing libido and treating erectile dysfunction. However, not many studies have been done to evaluate the sexual enhancing properties of A. tuberosum. The aim of this study was to evaluate the aphrodisiac and vasorelaxant properties of A. tuberosum on corpus cavernosum smooth muscle (CCSM) as well as checking the effect on enhancing male rat sexual behavior, libido, potency as well as its spermatogenic properties.

METHOD

The seeds were powdered and sequentially extracted with hexane, ethyl acetate and butanol. Male Wistar rats were administered with graded doses of the n-BuOH extracts (ATB) of A. tuberosum (50, 100, 200 and 400 mg/kg) and Viagra was used as the positive control drug. The extract/drug was administered by gastric probe once daily for 45 days and the sexual behavior was analyzed by exposing the male rats to female rats in the estrus period.

RESULTS

ATB relaxed corpus cavernosum smooth muscle (68.9%) at a concentration of 200 μg/ml. The results obtained from the animal studies indicated that ATB significantly increased mount frequency (MF), intromission frequency (IF), ejaculation frequency (EF), ejaculation latency (EL) and markedly reduced post ejaculatory interval (PEI), mount latency (ML), and intromission latency (IL). Furthermore, a remarkable increase in the test for potency was observed as witnessed by marked increase in erections, quick flips, long flips and total reflex. In addition, ATB significantly improved the sperm viability and count as well as increased the concentrations of testosterone, follicle stimulating hormone (FSH), and phosphatases in the treated animals.

CONCLUSION

Thus our results suggest that A. tuberosum could stimulate sexual arousal and enhance sexual execution in male rats, thus providing valuable experimental evidence that A. tuberosum possesses sexual enhancing properties.

Spirostanol steroids from the roots of Allium tuberosum

Three new spirostanol saponins named tuberosines A-C (1-3), together with three known ones tuberoside O (4), 25(S)-Schidigera-saponin D5 (5), and shatavarin IV (6) were isolated from the roots of Allium tuberosum. Their structures were established on the basis of extensive spectroscopic analyses. Whereas compounds 5 and 6 exhibited potent antibacterial activities against Bacillus subtilis (32 μg/mL) and Escherichia coli (16 μg/mL), the new saponin 2 showed only moderate antibacterial activities against these pathogens. The relationship between the antibacterial activities and the structures of these saponins are described.

Laboratory Evaluation of Larvicidal Activity of the Essential oil of Allium tuberosum Roots and its Selected Major Constituent Compounds Against Aedes albopictus (Diptera: Culicidae)

The aim of this research was to evaluate larvicidal activity of the essential oil of Allium tuberosum Rottler ex Sprengle roots and its constituents against larval mosquitoes (Aedes albopictus Skuse). Essential oil of A. tuberosum was obtained by hydrodistillation and analyzed by gas chromatography and gas chromatography-mass spectrometry. The major constituents of the oil were found to be sulfur-containing compounds, including allyl methyl trisulfide (35.19%), diallyl disulfide (28.31%), diallyl trisulfide (20.91%), and dimethyl trisulfide (12.33%). The essential oil of A. tuberosum exhibited larvicidal activity against the fourth-instar larvae of Ae. albopictus, with an LC50 value of 18 μg/ml. The constituents compounds-diallyl trisulfide (LC50 = 4 μg/ml) and diallyl disulfide (LC50 = 6 μg/ml)-possessed stronger larvicidal activity than allyl methyl trisulfide (LC50 = 27 μg/ml) and dimethyl trisulfide (LC50 = 35 μg/ml) against the fourth-instar larvae of Ae. albopictus. The results indicated that the essential oil of A. tuberosum and its major constituents have good potential as a source for natural larvicides.

Purification and characterization of a novel lectin from Chinese leek seeds

A novel lectin, CLSL, was purified from Chinese leek seeds by ion exchange chromatography on SP Sephadex C-25 and gel filtration chromatography on Sephadex G50. The lectin had a molecular weight of 23.6 kDa and was composed of two identical subunits linked by disulfide bonds, a conclusion based on SDS-PAGE under reducing and nonreducing conditions. CLSL was a glycoprotein with a carbohydrate content of 3.6%. It exerted potent agglutinating activity against rat red blood cells at a concentration of 8.9 μg/mL. Hemagglutination of rat erythrocytes was inhibited by d-fructose, mannitol, and sorbose at the concentration of 20 mM. The hemagglutinating activity of CLSL was maintained at 100 °C for 60 min and under acidic pH conditions but was lost at neutral and alkaline pH conditions. The hemagglutinating activity was stimulated by Ca(2+), Fe(2+), and Cu(2+) but inactivated by Ba(2+) at a concentration of 10 mM. Ba(2+)-mediated inactivation of CLSL was caused by CLSL conformational change induced by barium ions, according to the results of circular dichroism and fluorescence spectroscopy. Deconvolution of the CLSL circular dichroism indicated that it was an α-helical lectin with α-helix and β-fold contents of 35.8% and 8.6%, respectively. CLSL could also selectively inhibit cell proliferation.

Steroidal saponins from the genus Allium

Steroidal saponins are widely distributed among monocots, including the Amaryllidaceae family to which the Allium genus is currently classified. Apart from sulfur compounds, these are important biologically active molecules that are considered to be responsible for the observed activity of Allium species, including antifungal, cytotoxic, enzyme-inhibitory, and other. In this paper, literature data concerning chemistry and biological activity of steroidal saponins from the Allium genus has been reviewed.

Two novel furostanol saponins from the tubers of Ophiopogon japonicus

Phytochemical investigation of the fresh tubers of Ophiopogon japonicus led to the isolation of two new furostanol saponins (1 and 2) together with two known steroidal saponins (3 and 4). Comprehensive spectroscopic analysis allowed the chemical structures of two new compounds to be elucidated as (25R)-26-O-[β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl]-5-ene-furost-1β,3β,22α,26-tetraol-3-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 4)]-β-d-glucopyranoside (1, ophiopogonin P) and (25R)-26-O-[β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl]-5-ene-furost-1β,3β,22α,26-tetraol-3-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 4)]-β-d-glucopyranoside (2, ophiopogonin Q). Furostanol saponins with the disaccharide chain linked at C-26 hydroxy group of the aglycone have been rarely reported from natural sources.

Aphrodisiac properties of Allium tuberosum seeds extract

AIM OF THE STUDY

In the present study, we examined the effect of Allium tuberosum seeds extract upon the expression of male rat sexual behavior, in order to know whether Allium tuberosum seeds extract possess aphrodisiac property.

MATERIALS AND METHODS

The aphrodisiac activity of Allium tuberosum seeds n-BuOH extract was investigated in male rats. The extract (500 mg/kg body weight/day) and L-dopa (100 mg/kg body weight/day) were administered orally by gavages for 40 days. Mount latency (ML), intromission latency (IL), ejaculation latency (EL),mounting frequency (MF), intromission frequency (IF), ejaculation frequency (EF) and post-ejaculatory interval (PEI) were the parameters observed before and during the sexual behavior study at day 0, 10, 20, 30 and 40.

RESULTS

The n-BuOH extract reduced significantly ML, IL, EL and PEI (p < 0.05). The extract also increased significantly MF, IF and EF (p < 0.05). These effects were observed in sexually active and inactive male rats.

CONCLUSIONS

Present findings provide experimental evidence that the n-BuOH extract preparation of Allium tuberosum seeds possesses aphrodisiac property.