Resistant starch from yam: Preparation, nutrition, properties and applications in the food sector.

Yam is a significant staple food and starch source, particularly in tropical and subtropical regions, holding the fourth position among the world's top ten tuber crops. Yam tubers are rich in essential nutrients and a diverse range of beneficial plant compounds, which contribute to their multifaceted beneficial functions. Furthermore, the abundant starch and resistant starch (RS) content in yam can fulfil the market demand for RS. The inherent and modified properties of yam starch and RS make them versatile ingredients for a wide range of food products, with the potential to become one of the most cost-effective raw materials in the food industry. In recent years, research on yam RS has experienced progressive expansion. This article provides a comprehensive summary of the latest research findings on yam starch and its RS, elucidating the feasibility of commercial RS production and the technology's impact on the physical and chemical properties of starch. Yam has emerged as a promising reservoir of tuber starch for sustainable RS production, with thermal, chemical, enzymatic and combination treatments proving to be effective manufacturing procedures for RS. The adaptability of yam RS allows for a wide range of food applications.

Antibacterial activity of Dioscorea bulbifera Linn. extract and its active component flavanthrinin against skin-associated bacteria.

BACKGROUND: Dioscorea bulbifera Linn. has been used for wound care in Thailand. However, a comprehensive evaluation of its antibacterial activity is required. This study aimed to investigate the antibacterial efficacy of D. bulbifera extract against skin-associated bacteria and isolate and characterize its active antibacterial agent, flavanthrinin. METHODS: Air-dried bulbils of D. bulbifera were pulverised and extracted with hexane, dichloromethane, ethyl acetate, methanol, ethanol, and distilled water; vacuum filtered; concentrated; freeze-dried; and stored at -20 ºC. Antibacterial activity of the extracts was assessed using microdilution techniques against several skin-associated bacteria. Thin-layer chromatography (TLC) bioautography was used to identify the active compounds in the extract, which were fractionated by column chromatography and purified by preparative TLC. The chemical structures of the purified compounds were analysed using nuclear magnetic resonance (NMR). The cytotoxicity of the extract and its active compounds was evaluated in Vero cells. RESULTS: The ethyl acetate extract exhibited distinct inhibition zones against bacteria compared to other extracts. Therefore, the ethyl acetate extract of D. bulbifera in the ethyl acetate layer was used for subsequent analyses. D. bulbifera extract exhibited antibacterial activity, with minimum inhibitory concentrations (MICs) of 0.78-1.56 mg/mL. An active compound, identified through TLC-bioautography, demonstrated enhanced antibacterial activity, with MICs of 0.02-0.78 mg/mL. NMR analysis identified this bioactive compound as flavanthrinin. Both D. bulbifera extract and flavanthrinin-containing fraction demonstrated potent antibacterial activity against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and S. epidermidis. The flavanthrinin containing fraction demonstrated low cytotoxicity against Vero cells, showing CC50 values of 0.41 ± 0.03 mg/mL. These values are lower than the MIC value, indicating that this fraction is safer than the initial ethyl acetate extract. CONCLUSIONS: Dioscorea bulbifera extract and its bioactive component flavanthrinin demonstrated significant antibacterial activity against the skin-associated bacteria Staphylococci, including MRSA. Flavanthrinin has potential as a complementary therapeutic agent for managing skin infections owing to its potent antibacterial effects and low cytotoxicity.

Molecular mechanism for the influence of yam starch multiscale structure on the sensory texture of cooked yam.

Yam is a dual-purpose crop as both medicine and food. However, the mechanism controlling the eating quality of yam remains to be elucidated. This study explored the influence of starch multiscale structure on the texture of yam. The results indicated that FS and RC yam have higher hardness and chewiness, while BZ, XM, and PL yam possess waxiness, Fineness, and Stickiness. Statistically, high amylose (AM) can increase hardness, chewiness, and compactness; and average molecular size (Rh) is positively correlated with stickiness, fineness, and waxiness. Specifically, medium- and long-chain amylose (1000 < X ≤ 10,000) and amylopectin (24 < X ≤ 100), particularly medium-chain amylose (1000 < X ≤ 5000) and long-chain amylopectin (24 < X ≤ 36), primarily affect sensory and rheological stickiness. The long chains of amylose form a straight chain interspersed in the crystalline and amorphous regions to support the entire lamellar structure. Higher proportion of amylose long chains, promoting the starch's structural rigidity, which in turn enhanced its hardness-related attributes. Moreover, a higher ratio of long chains within amylopectin results in tightly intertwined adjacent outer chains, forming double helix crystalline zones. This consequently augmenting the texture quality linked to stickiness-related attributes.

The anti-non-small cell lung cancer effect of Diosbulbin B: Targeting YY1 induced cell cycle arrest and apoptosis.

BACKGROUND: Toxic components frequently exhibit unique characteristics and activities, offering ample opportunities for the advancement of anti-cancer medications. As the main hepatotoxic component of Dioscorea bulbifera L. (DB), Diosbulbin B (DIOB) has been widely studied for its anti-tumor activity at nontoxic doses. However, the effectiveness and mechanism of DIOB against non-small cell lung cancer (NSCLC) remains unclear. PURPOSE: To evaluate the anti-NSCLC activity of DIOB and to elucidate the specific mechanism of action. METHOD: The effect of DIOB on NSCLCL in vitro was evaluated through CCK8, colony formation, and flow cytometry. The in vivo efficacy and safety of DIOB in treating NSCLC were assessed using various techniques, including HE staining, tunel staining, immunohistochemistry, and biochemical index detection. To understand the underlying mechanism, cell transfection, western blotting, molecular docking, cellular thermal shift assay (CESTA), and surface plasmon resonance (SPR) were employed for investigation. RESULTS: DIOB effectively hindered the progression of NSCLC both in vitro and in vivo settings at a no-observed-adverse-effect concentration (NOAEC) and a safe dosage. Specifically, DIOB induced significant G0/G1 phase arrest and apoptosis in A549, PC-9, and H1299 cells, while also notably inhibiting the growth of subcutaneous tumors in nude mice. Mechanistically, DIOB could directly interact with oncogene Yin Yang 1 (YY1) and inhibit its expression. The reduction in YY1 resulted in the triggering of the tumor suppressor P53, which induced cell cycle arrest and apoptosis in NSCLC cells by inhibiting the expression of Cyclin A2, B2, CDK1, CDK2, CDK4, BCL-2, and inducing the expression of BAX. In NSCLC cells, the induction of G0/G1 phase arrest and apoptosis by DIOB was effectively reversed when YY1 was overexpressed or P53 was knocked down. Importantly, we observed that DIOB exerted the same effect by directly influencing the expression of YY1-regulated c-Myc and BIM, particularly in the absence of P53. CONCLUSION: For the inaugural investigation, this research unveiled the anti-NSCLC impact of DIOB, alongside its fundamental mechanism. DIOB has demonstrated potential as a treatment agent for NSCLC due to its impressive efficacy in countering NSCLC.

[Study on mechanism of Chinese Yam polysaccharide synergizing nucleoside analogues against hepatitis B virus through p38 MAPK signaling pathway].

This study explore the molecular mechanism of the synergistic effect of Chinese Yam polysaccharides and nucleoside analogues(NAs) on hepatitis B virus(HBV) resistance. Different concentrations of Chinese Yam polysaccharide and entecavir were ad-ded to HepG2.2.15 cells. After the cytotoxicity was detected by cell counting kit-8(CCK-8), the optimal concentration and time of the two drugs to inhibit HepG2.2.15 cells were screened out. They were divided into control group, Chinese Yam polysaccharide group, entecavir group and combination drug group(Chinese Yam polysaccharide + entecavir). The drugs were added to HepG2.2.15 cells, ELISA was used to detect the effects of each group of drugs on the secretion of hepatitis B virus surface antigen(HBsAg) and hepatitis B virus e antigen(HBeAg) in cell supernatant, probe quantitative real-time PCR(probe qRT-PCR) was used to detect the effects of drugs on HBV-DNA in HepG2.2.15 cells, and Western blot was used to detect the effects of each group of drugs on the expression of p38 MAPK, p-p38 MAPK, NTCP proteins in HepG2.2.15 cells. The qRT-PCR was used to detect the effect of drugs on the expression of p38 MAPK and NTCP mRNA in HepG2.2.15 cells. The results showed that compared with control group, the concentrations of HBeAg and HBsAg in Chinese Yam polysaccharide group, entecavir group and combination group decreased(P<0.01 or P<0.001), and both of them inhibited HBV-DNA in HepG2.2.15 cells(P<0.01), and the HBV-DNA inhibition of HepG2.2.15 cells in the combination group was more obvious(P<0.001), and the protein expression levels of p-p38 MAPK and NTCP were significantly decreased(P<0.05 or P<0.01), the mRNA expression level of p38 MAPK increased, and the mRNA expression level of NTCP decreased(P<0.05 or P<0.01). To sum up, Chinese Yam polysaccharide can reduce the expression of NTCP protein and mRNA through p38 MAPK signaling pathway and cooperate with entecavir in anti-HBV.

Investigating the impact of ultrasound on the structural, physicochemical, and emulsifying characteristics of Dioscorin: Insights from experimental data and molecular dynamics simulation.

This study investigated the impact of ultrasound treatment on dioscorin, the primary storage protein found in yam tubers. Three key factors, namely ultrasound power, duration, and frequency, were focused on. The research revealed that ultrasound-induced cavitation effects disrupted non-covalent bonds, resulting in a reduction in α-helix and ß-sheet contents, decreased thermal stability, and a decrease in the apparent hydrodynamic diameter (Dh) of dioscorin. Additionally, previously hidden amino acid groups within the molecule became exposed on its surface, resulting in increased surface hydrophobicity (Ho) and zeta-potential. Under specific ultrasound conditions (200 W, 25 kHz, 30 min), Dh decreased while Ho increased, facilitating the adsorption of dioscorin molecules onto the oil-water interface. Molecular dynamics (MD) simulations showed that at lower frequencies and pressures, the structural flexibility of dioscorin's main chain atoms increased, leading to more significant fluctuations between amino acid residues. This transformation improved dioscorin's emulsifying properties and its oil-water interface affinity.

Effects of cooking methods on the physical properties and in vitro digestibility of starch isolated from Chinese yam.

The objective of this study was to compare the structural and functional attributes of Chinese yam starches obtained via different domestic cooking methods. Cooking changed the crystalline type from the C type to the CB type, and disrupted the short- and long-range molecular order of Chinese yam starch. The average chain length of amylopectin in BOS (boiling starch) was the smallest at 22.78, while RWS had the longest average chain length, reaching 24.24. These alterations in molecular structure resulted in variations in functional properties such as solubility, swelling power (SP), pasting characteristics, and rheological properties. Among these alterations, boiling was the most effective method for increasing the water-binding capacity and SP of starch. Specifically, its water holding capacity was 2.12 times that of RWS. In vitro digestion experiments indicated that BOS has a higher digestion rate (k = 0.0272 min-1) and lower RDS (rapidly digestible starch), which may be related to its amylopectin chain length distribution. This study can guide us to utilize yam starch through suitable cooking methods, which is relevant for the processing and application of Chinese yam starch.

Structural characterization and immunomodulatory activity of a polysaccharide from Dioscotea opposita.

The purified polysaccharides fraction, DOP-2, was prepared from Dioscorea opposita Thunb (D. opposita). This study combined in vitro and in vivo experiments to comprehensively investigate the index changes in RAW264.7 cells and immunocompromised mice under DOP-2 intervention, aiming to elucidate the potential mechanisms of immunomodulatory effects of DOP-2. DOP-2 (10 âˆ¼ 500 µg/mL) significantly elevated the levels of NO, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) factors secreted by RAW264.7 cells, and restored the body weight of immunosuppressed mice and improve the degree of injury to the immune organ index, resulting in significant immunomodulatory effects. Notably, DOP-2 promoted the production of short-chain fatty acids (SCFAs) in immunosuppressed mice and modulated the composition of their gut microflora. These findings highlight the potential benefits of DOP-2 therapy in improving immune function and gut health, and will provide a theoretical basis for the application of D. opposita polysaccharides as an immunomodulatory adjuvant.

Prospects of yam (Dioscorea) polysaccharides: Structural features, bioactivities and applications.

Yam (Dioscorea) is a tuber crop cultivated for food security, revenue, and medicinal purposes. It has been used to treat diabetes, asthma, diarrhea, and other diseases. The main active ingredients in yam, polysaccharides, are regarded to be the important reason for its widespread applications. Now, a comprehensive review of research developments of yam polysaccharides (YPs) was presented to explore their prospects. We outlined the structural characteristics, biological activities, structure-activity relationships, and potential applications. Around 13 neutral components and 17 acidic components were separated. They exhibited various bioactivities, including immunomodulatory, hypoglycemic, hypolipidemic, antioxidant, gastrointestinal protective, anti-fatigue, and senile disease treatment activities, as well as prebiotic effect. Structure-activity relationships illustrated that unique structural properties, chemical modifications, and carried biopolymers could influence the bioactivities of YPs. The potential applications in medicine, food, and other fields have also been summarized.

Effect of extrusion on the formation, structure and properties of yam starch-gallic acid complexes.

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch.

The genus Dioscorea L. (Dioscoreaceae), a review of traditional uses, phytochemistry, pharmacology, and toxicity.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Dioscorea, a member of the Dioscoreaceae family, comprises approximately 600 species and is widely distributed across temperate and tropical regions such as Asia, South Africa, and North America. The traditional medicinal uses of Dioscorea have been documented in Asian and African pharmacological systems. In Asia, this genus is traditionally used to treat respiratory illnesses, rheumatism, diabetes, diarrhea, dysentery, and other conditions. In Africa, this genus has been used to treat human immunodeficiency virus and ring worms. However, the traditional medicinal practices in North America rarely mention the use of this genus. AIM OF THE STUDY: The aim of this review is to comprehensively review the genus Dioscorea, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. The research also aims to highlight the valuable bioactive compounds within Dioscorea and emphasize the need for further investigations into acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors to contribute to the discovery of novel pharmaceuticals. MATERIALS AND METHODS: A search for available information on Dioscorea was conducted using scientific databases, including PubMed, ISI-WOS, Scopus, and Google Scholar, as well as recent academic publications from reputable publishers and other literature sources. The search was not limited by language and spanned the literature published between 1950 and 2022. RESULTS: This article provides a comprehensive review of the Dioscorea genus, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. Extensive research has been conducted on this genus, resulting in the isolation and examination of over 1000 compounds, including steroids, terpenoids, and flavonoids, to determine their biological activities. These activities include anti-tumor, anti-inflammatory, immunomodulatory, neuroprotective, hypoglycemic, and hypolipidemic effects. However, some studies have indicated the potential toxicity of high doses of Dioscorea, highlighting the need for further investigations to assess the safety of this genus. Additionally, this review explores potential avenues for future research and discusses the challenges associated with a comprehensive understanding of the Dioscorea genus. CONCLUSIONS: Based on the existing literature, it can be concluded that Dioscorea is a valuable source of bioactive compounds that have the potential to treat various disorders. Future research should prioritize the investigation of acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors. This review provides a comprehensive analysis of the Dioscorea genus, emphasizing its potential to enable a deeper exploration of the biological activity mechanisms of these plants and contribute to the discovery of novel pharmaceuticals.

Efficient discovery of active isolates from Dioscorea spongiosa by the combination of bioassay-guided macroporous resin column chromatography and high-speed counter-current chromatography.

In the present study, twelve compounds from Dioscorea spongiosa were successfully purified by an efficient technique combined bioassay-guided fractionation macroporous resin column chromatography (MRCC) pretreatment and high-speed counter-current chromatography (HSCCC) separation for the first time. Then, D101 MRCC was used to fractionate the crude extract into five parts, which further applied the bioassay-guided fractionation strategy to screen the active fractions of 2 and 4. As for the separation, 200 mg Fr.2 was purified by HSCCC using EtOAc/n-BuOH/H2 O (2:2:3, v/v), leading to annulatomarin (1), dioscoresides C (2), diosniponol C (3), methyl protodioscin (4), pseudoprotodioscin (5), protogracillin (6), as well as 200 mg Fr.4 yielding montroumarin (7), dioscorone A (8), diosniponol D (9), protodioscin (10), gracillin (11), and dioscin (12) using CH2 Cl2 /MeOH/H2 O (3:3:2, v/v) with the purities over 95.0%. Finally, the isolates were assayed for their anti-inflammatory, urico-lowering, and anti-diabetic activities in vitro, which indicated that the steroidal saponins of 5, 6, and 11 showed all these three activities.

Unveiling the impact of harvest time on Dioscorea opposita Thunb. cv. Tiegun maturity by NMR-based metabolomics and LC-MS/MS analysis.

BACKGROUND: Dioscorea opposita Thunb. cv. Tiegun maturity (DM) is an important factor influencing its quality. However, there are few studies on the impact of harvest time on its maturation. In the present study, a NMR-based metabolomics approach was applied to investigate the dynamic metabolic changes of D. opposita Thunb. cv. Tiegun at six different harvest stages: stage 1 (S1), stage 2 (S2), Stage 3 (S3), stage 4 (S4), stage 5 (S5) and stage 6 (S6). RESULTS: Principal component analysis showed distinct segregation of samples obtained from S1, S2 and S3 compared to those derived from S4, S5 and S6. Interestingly, these samples from the two periods were obtained before and after frost, indicating that frost descent might be important for DM. Eight differential metabolites responsible for good separation of different groups were identified by the principal component analysis loading plot and partial least squares-discriminant analysis. In addition, quantitative analysis of these metabolites using liquid chromatography-tandem mass spectrometry determined the effects of harvest time on these metabolite contents, two of which, sucrose and allantoin, were considered as potential biomarkers to determine DM. CONCLUSION: The present study demonstrated that NMR-based metabolomics approach could serve as a powerful tool to identify differential metabolites during harvesting processes, also offering a fresh insight into understanding the DM and the potential mechanism of quality formation. © 2024 Society of Chemical Industry.

DbGTi: Thermostable trypsin inhibitor from Dioscorea bulbifera L. ground tubers: assessment of antioxidant and antibacterial properties and cytotoxicity evaluation using zebrafish model.

Oxidative stress disorders and diseases caused by drug-resistant bacteria have emerged as significant public health concerns. Plant-based medications like protease inhibitors are growing despite adverse effects therapies. Consecutively, in this study, trypsin inhibitors from Dioscorea bulbifera L. (DbGTi trypsin inhibitor) ground tubers were isolated, purified, characterized, and evaluated for their potential cytotoxicity, antibacterial, and antioxidant activities. DbGTi protein was purified by Q-Sepharose matrix, followed by trypsin inhibitory activity. The molecular weight of the DbGTi protein was found to be approximately 31 kDa by SDS-PAGE electrophoresis. The secondary structure analysis by circular dichroism (CD) spectroscopy revealed that the DbGTi protein predominantly comprises ß sheets followed by α helix. DbGTi protein showed competitive type of inhibition with Vmax = 2.1372 × 10-1 µM/min, Km = 1.1805 × 102 µM, & Ki = 8.4 × 10-9 M and was stable up to 70 °C. DbGTi protein exhibited 58 % similarity with Dioscorin protein isolated from Dioscorea alata L. as revealed by LC-MS/MS analysis. DbGTi protein showed a non-toxic effect, analyzed by MTT, Haemolytic assay and in vivo studies on zebrafish model. DbGTi protein significantly inhibited K. pneumoniae and has excellent antioxidant properties, confirmed by various antioxidant assays. The results of anti-microbial, cytotoxicity and antioxidant assays demonstrate its bioactive potential and non-toxic nature.

Research progress on the structure, derivatives, pharmacological activity, and drug carrier capacity of Chinese yam polysaccharides: A review.

Chinese yam is a traditional Chinese medicine that has a long history of medicinal and edible usage in China and is widely utilised in food, medicine, animal husbandry, and other industries. Chinese yam polysaccharides (CYPs) are among the main active components of Chinese yam. In recent decades, CYPs have received considerable attention because of their remarkable biological activities, such as immunomodulatory, antitumour, hypoglycaemic, hypolipidaemic, antioxidative, anti-inflammatory, and bacteriostatic effects. The structure and chemical alterations of polysaccharides are the main factors affecting their biological activities. CYPs are potential drug carriers owing to their excellent biodegradability and biocompatibility. There is a considerable amount of research on CYPs; however, a systematic summary is lacking. This review summarises the structural characteristics, derivative synthesis, biological activities, and their usage as drug carriers, providing a basis for future research, development, and application of CYPs.

Investigation of the principle of concoction by using the processing excipient Glycyrrhiza uralensis Fisch. juice to reduce the main toxicity of Dioscorea bulbifera L. and enhance its main efficacy as expectorant and cough suppressant.

ETHNOPHARMACOLOGICAL RELEVANCE: Dioscorea bulbifera L. (Rhizoma Dioscoreae Bulbiferae; RDB) is commonly used as an expectorant and cough suppressant herb but is accompanied by severe hepatotoxicity. Using the juice of auxiliary herbs (such as Glycyrrhiza uralensis Fisch. (Glycyrrhizae Radix et Rhizoma; GRR) juice) in concocting poisonous Chinese medicine is a conventional method to reduce toxicity or increase effects. Our previous study found that concoction with GRR juice provided a detoxifying effect against the major toxic hepatotoxicity induced by RDB, but the principle for the detoxification of the concoction is unknown to date. AIM OF THE STUDY: The principle of concoction was investigated by using the processing excipient GRR juice to reduce the major toxic hepatotoxicity of RDB, and the efficacy of RDB as an expectorant and cough suppressant was enhanced. MATERIALS AND METHODS: In this study, common factors (RDB:GRR ratio, concocted temperature, and concocted time) in the concoction process were used for the preparation of each RDB concocted with GRR juice by using an orthogonal experimental design. We measured the content of the main toxic compound diosbulbin B (DB) and serum biochemical indicators and performed pathological analysis in liver tissues of mice to determine the best detoxification process of RDB concocted with GRR juice. On this basis, the biological mechanisms of target organs were detected by Western blot and enzyme-linked immunosorbent assay at the inflammation and apoptosis levels. Further, the effects of RDB on expectorant and cough suppressant with GRR juice were evaluated by the conventional tests of phenol red expectorant and concentrated ammonia-induced cough. Lastly, the major compounds in the GRR juice introduced to RDB concoction were determined. RESULTS: RDB concocted with GRR juice significantly alleviated DB content, serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase levels, and improved liver pathological damages. The best detoxification process was achieved by using an RDB:GRR ratio of 100:20 at 120 °C for 20 min. Further, RDB concocted with GRR juice down-regulated the protein levels of nuclear factor kappa B (NF-κB), cyclooxygenase 2 (COX-2), and Bcl-2 related X protein (Bax) in the liver and enhanced the expectorant and cough suppressant effects of RDB. Finally, liquiritin (LQ) and glycyrrhizic acid (GA) in the GRR juice were introduced to the RDB concoction. CONCLUSION: Concoction with GRR juice not only effectively reduced the major toxic hepatotoxicity of RDB but also enhanced its main efficacy as an expectorant and cough suppressant, and that the rationale for the detoxification and/or potentiation of RDB was related to the reduction in the content of the main hepatotoxic compound, DB, the introduction of the hepatoprotective active compounds, LQ and GA, in the auxiliary GRR juice, as well as the inhibition of NF-κB/COX-2/Bax signaling-mediated inflammation and apoptosis.

The Isolation, Identification and Immobilization Method of Three Novel Enzymes with Diosgenin-Producing Activity Derived from an Aspergillus flavus.

Diosgenin is an important raw material used in the synthesis of steroid drugs, and it is widely used in the pharmaceutical industry. The traditional method of producing diosgenin is through using raw materials provided via the plant Dioscorea zingiberensis C. H. Wright (DZW), which is subsequently industrially hydrolyzed using a high quantity of hydrochloric and sulfuric acids at temperatures ranging from 70 °C to 175 °C. This process results in a significant amount of unmanageable wastewater, creates issues of severe environmental pollution and consumes high quantities of energy. As an alternative, the enzymolysis of DZW to produce diosgenin is an environmentally and friendly method with wide-ranging prospects for its application. However, there are still only a few enzymes that are suitable for production on an industrial scale. In this study, three new key enzymes, E1, E2, and E3, with a high conversion stability of diosgenin, were isolated and identified using an enzyme-linked-substrate autography strategy. HPLC-MS/MS identification showed that E1, a 134.45 kDa protein with 1019 amino acids (AAs), is a zinc-dependent protein similar to the M16 family. E2, a 97.89 kDa protein with 910 AAs, is a type of endo-ß-1,3-glucanase. E3, a 51.6 kDa protein with 476 AAs, is a type of Xaa-Pro aminopeptidase. In addition, the method to immobilize these proteins was optimized, and stability was achieved. The results show that the optimal immobilization parameters are 3.5% sodium alginate, 3.45% calcium chloride concentration, 1.4 h fixed time, and pH 8.8; and the recovery rate of enzyme activity can reach 43.98%. A level of 70.3% relative enzyme activity can be obtained after employing six cycles of the optimized technology. Compared with free enzymes, immobilized enzymes have improved stability, acid and alkaline resistance and reusability, which are conducive to large-scale industrial production.

Chinese Yam and Its Active Components Regulate the Structure of Gut Microbiota and Indole-like Metabolites in Anaerobic Fermentation In Vitro.

As a medicinal and edible plant, Chinese yam (CY) can promote the enrichment of intestinal probiotics. Mucilage polysaccharides, diosgenin and taxifolin are the dominant components of CY. The purpose of this study was to investigate whether the impact of Chinese yam on gut microbiome structure and metabolism is attributable to its components. In the in vitro gastrointestinal digestion and colon fermentation system, the changes in gut microbiota composition and function were determined by 16S rRNA sequencing, and the levels of bacterial metabolites including short-chain fatty acids (SCFAs) and indole-like metabolites were detected by gas chromatography and an enzyme-linked immunoassay. The results show that CY, mucilage polysaccharides, diosgenin and taxifolin could increase the microbial diversity index. Furthermore, probiotics including Lactobacillus and Bacteroides were significantly increased, while harmful bacteria such as Escherichia and Proteus declined. CY could increase the production of SCFAs including acetic acid and butyric acid. Of note, CY and diosgenin displayed similar impacts on enhancing the abundance of Clostridium and promoting the production of indole-3-lactic acid and lactic acid. These findings provide evidence supporting Chinese yam as a natural food to regulate intestinal health. Diosgenin as a component of CY contributes mostly to the impact on regulating intestinal flora.

Widely Targeted Metabolomics Reveals the Effects of Soil on the Metabolites in Dioscorea opposita Thunb.

Chinese yam (Dioscorea opposita Thunb. cv. Tiegun), a type of homologous medicinal plant, mainly grows in sandy soil (SCY) and loessial soil (LCY). However, the effects of the soil on the metabolites in SCY and LCY remain unclear. Herein, this study aims to comprehensively elucidate the metabolites in SCY and LCY. A UPLC-MS/MS-based, widely targeted metabolomics approach was adapted to compare the chemical composition of SCY and LCY. A total of 988 metabolites were detected, including 443 primary metabolites, 510 secondary metabolites, and 35 other compounds. Notably, 177 differential metabolites (classified into 12 categories) were identified between SCY and LCY; among them, 85.9% (152 differential metabolites) were upregulated in LCY. LCY significantly increased the contents of primary metabolites such as 38 lipids and 6 nucleotides and derivatives, as well as some secondary metabolites such as 36 flavonoids, 28 phenolic acids, 13 alkaloids, and 6 tannins. The results indicate that loessial soil can improve the nutritional and medicinal value of D. opposita.

Isolation and identification of active ingredients and biological activity of Dioscorea nipponica Makino.

This study reported the isolation and identification of bioactive compounds from Dioscorea nipponica Makino, a plant used in traditional medicine for various ailments. Nine compounds were isolated, including a new compound named as diosniposide E, which was elucidated by analyzing its 1H-NMR, 13C-NMR, DEPT, COSY, HMBC and MS data and comparing them with data available in literature. The other eight compounds were identified as known compounds. Theoretical calculations of energy and the generation of a molecular electrostatic potential surface map were employed to assess the antioxidant capacity of nine compounds, the calculation results exhibited that compounds 5 and 6 had strong antioxidant capacities. To further evaluate the antioxidant activities of the investigated compounds, the DPPH and ABTS assays were conducted. The results from the DPPH scavenging activity test revealed that compounds 4-6 exhibited enhanced scavenging activities compared to L-ascorbic acid, while displaying similar efficacy to trolox. Moreover, the ABTS scavenging activities of compounds 4-6 were found to surpass those of L-ascorbic acid and trolox. In terms of α-glucosidase inhibition, compounds 3 and 4 displayed remarkable inhibitory activities that surpassed the effects of acarbose. Additionally, compound 2 exhibited potent anticholinesterase activities, outperforming donepezil. This research provides insights into the potential bioactive compounds present in Dioscorea nipponica Makino and may contribute to its use in traditional medicine.