Molecular Cloning and Functional Characterization of a Sterol 3-O-Glucosyltransferase Involved in Biosynthesis of Steroidal Saponins in Trigonella foenum-graecum

Recent developments in the enzymatic modifications of steroid scaffolds

Steroids are an important family of bioactive compounds. Steroid drugs are renowned for their multifaceted pharmacological activities and are the second-largest category in the global pharmaceutical market. Recent developments in biocatalysis and biosynthesis have led to the increased use of enzymes to enhance the selectivity, efficiency, and sustainability for diverse modifications of steroids. This review discusses the advancements achieved over the past five years in the enzymatic modifications of steroid scaffolds, focusing on enzymatic hydroxylation, reduction, dehydrogenation, cascade reactions, and other modifications for future research on the synthesis of novel steroid compounds and related drugs, and new therapeutic possibilities.

An In Vitro Study on the Cytotoxic, Antioxidant, and Antimicrobial Properties of Yamogenin-A Plant Steroidal Saponin and Evaluation of Its Mechanism of Action in Gastric Cancer Cells

Yamogenin is a steroidal saponin occurring in plant species such as Asparagus officinalis, Dioscorea collettii, Trigonella foenum-graecum, and Agave sp. In this study, we evaluated in vitro cytotoxic, antioxidant, and antimicrobial properties of yamogenin. The cytotoxic activity was estimated on human colon cancer HCT116, gastric cancer AGS, squamous carcinoma UM-SCC-6 cells, and human normal fibroblasts with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The amount of apoptotic and dead AGS cells after treatment with yamogenin was estimated with flow cytometry. Also, in yamogenin-treated AGS cells we investigated the reactive oxygen species (ROS) production, mitochondrial membrane depolarization, activity level of caspase-8 and -9, and gene expression at mRNA level with flow cytometry, luminometry, and RT-PCR, respectively. The antioxidant properties of yamogenin were assessed with DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays. The antimicrobial potential of the compound was estimated on Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae, Escherichia coli, Salmonella enterica, Helicobacter pylori, Campylobacter coli, Campylobacter jejuni, Listeria monocytogenes, Lactobacillus paracasei, and Lactobacillus acidophilus bacteria strains. Yamogenin showed the strongest cytotoxic effect on AGS cells (IC50 18.50 ± 1.24 µg/mL) among the tested cell lines. This effect was significantly stronger in combinations of yamogenin with oxaliplatin or capecitabine than for the single compounds. Furthermore, yamogenin induced ROS production, depolarized mitochondrial membrane, and increased the activity level of caspase-8 and -9 in AGS cells. RT-PCR analysis revealed that this sapogenin strongly up-regulated TNFRSF25 expression at the mRNA level. These results indicate that yamogenin induced cell death via the extrinsic and intrinsic way of apoptosis. Antioxidant study showed that yamogenin had moderate in vitro potential (IC50 704.7 ± 5.9 µg/mL in DPPH and 631.09 ± 3.51 µg/mL in ABTS assay) as well as the inhibition of protein denaturation properties (with IC50 1421.92 ± 6.06 µg/mL). Antimicrobial test revealed a weak effect of yamogenin on bacteria strains, the strongest one being against S. aureus (with MIC value of 350 µg/mL). In conclusion, yamogenin may be a potential candidate for the treatment and prevention of gastric cancers.

Current perspectives on fenugreek bioactive compounds and their potential impact on human health: A review of recent insights into functional foods and other high value applications

Despite long-standing uses in several food and medicine traditions, the full potential of the leguminous crop fenugreek (Trigonella foenum-graecum L.) remains to be realized in the modern diet. Not only its seeds, which are highly prized for their culinary and medicinal properties, but also its leaves and stems abound in phytochemicals with high nutritional and health promoting attributes. Fenugreek dual food-medicine applications and reported metabolic activities include hypoglycemic, antihyperlipidemic, antioxidative, anti-inflammatory, antiatherogenic, antihypertensive, anticarcinogenic, immunomodulatory, and antinociceptive effects, with potential organ-protective effects at the cardiovascular, digestive, hepatic, endocrine, and central nervous system levels. Effectiveness in alleviating certain inflammatory skin conditions and dysfunctions of the reproductive system was also suggested. As a food ingredient, fenugreek can enhance the sensory, nutritional, and nutraceutical qualities of a wide variety of foods. Its high nutritive density can assist with the design of dietary items that meet the demand for novelty, variety, and healthier foods. Its seeds provide essential protective nutrients and other bioactive compounds, notably galactomannans, flavonoids, coumarins, saponins, alkaloids, and essential oils, whose health benefits, alone or in conjunction with other bioactives, are only beginning to be tapped into in the food industries. This review summarizes the current state of evidence on fenugreek potential for functional food development, focusing on the nutrients and non-nutrient bioactive components of interest from a dietary perspective, and their applications for enhancing the functional and nutraceutical value of foods and beverages. New developments, safety, clinical evidence, presumed mechanisms of action, and future perspectives are discussed. HIGHLIGHTS: Fenugreek seeds and leaves have long-standing uses in the food-medicine continuum. Fenugreek phytochemicals exert broad-spectrum biological and pharmacological activities. They show high preventive and nutraceutical potential against common chronic diseases. Current evidence supports multiple mechanisms of action mediated by distinct bioactives. Opportunities for fenugreek-based functional foods and nutraceuticals are expanding.

Diosgenin biosynthesis pathway and its regulation in Dioscorea cirrhosa L

Dioscorea cirrhosa L. (D. cirrhosa) tuber is a traditional medicinal plant that is abundant in various pharmacological substances. Although diosgenin is commonly found in many Dioscoreaceae plants, its presence in D. cirrhosa remained uncertain. To address this, HPLC-MS/MS analysis was conducted and 13 diosgenin metabolites were identified in D. cirrhosa tuber. Furthermore, we utilized transcriptome data to identify 21 key enzymes and 43 unigenes that are involved in diosgenin biosynthesis, leading to a proposed pathway for diosgenin biosynthesis in D. cirrhosa. A total of 3,365 unigenes belonging to 82 transcription factor (TF) families were annotated, including MYB, AP2/ERF, bZIP, bHLH, WRKY, NAC, C2H2, C3H, SNF2 and Aux/IAA. Correlation analysis revealed that 22 TFs are strongly associated with diosgenin biosynthesis genes (-r2- > 0.9, P < 0.05). Moreover, our analysis of the CYP450 gene family identified 206 CYP450 genes (CYP450s), with 40 being potential CYP450s. Gene phylogenetic analysis revealed that these CYP450s were associated with sterol C-22 hydroxylase, sterol-14-demethylase and amyrin oxidase in diosgenin biosynthesis. Our findings lay a foundation for future genetic engineering studies aimed at improving the biosynthesis of diosgenin compounds in plants.