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.

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.

Anti-papillary thyroid carcinoma effects of dioscorea bulbifera L. through ferroptosis and the PI3K/AKT pathway based on network pharmacology and experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Papillary thyroid carcinoma (PTC) is the predominant form of thyroid cancer with a rising global incidence. Despite favorable prognoses, a significant recurrence rate persists. Dioscorea bulbifera L. (DBL), a traditional Chinese medicine, has been historically used for thyroid-related disorders. However, its therapeutic effects and mechanisms of action on PTC remain unclear. AIM OF THE STUDY: To explore the potential therapeutic effects, principal active components, and molecular mechanisms of DBL in the treatment of PTC through network pharmacology and molecular docking, with experimental validation conducted to corroborate these findings. MATERIALS AND METHODS: The Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) was utilized as a systematic tool for collecting and screening the phytochemical components of DBL, and for establishing associations between these components and molecular targets. Based on this, network data was visually processed using Cytoscape software (version 3.8.0). Concurrently, precise molecular docking studies of the principal active components of DBL and their corresponding targets were conducted using Autodock software. Additionally, PTC-related genes were selected through the GeneCards and GEO databases. We further employed the DAVID bioinformatics resources to conduct comprehensive Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses on the intersecting genes between DBL and PTC. These analyses aid in predicting the potential therapeutic actions of DBL on PTC and its mechanisms of action. To validate these findings, corresponding in vitro experimental studies were also conducted. RESULTS: In this investigation, 14 bioactive compounds of DBL and 195 corresponding molecular targets were identified, with 127 common targets shared between DBL and PTC. Molecular docking revealed strong binding affinities between major bioactive compounds and target proteins. GO enrichment analysis unveiled key processes involved in DBL's action. KEGG analysis highlighted DBL's modulation of the PI3K/AKT signaling pathway. Experimental outcomes demonstrated DBL's potential in inhibiting PTC cell proliferation and migration, suppressing PI3K/AKT pathway activation, and promoting ferroptosis. CONCLUSION: In conclusion, DBL offers a multifaceted therapeutic approach for PTC, targeting multiple molecular entities and influencing diverse biological pathways. Network pharmacology and molecular docking shed light on DBL's potential utility in PTC treatment, substantiated by experimental validation. This study contributes valuable insights into using DBL as a promising therapeutic agent for PTC management.

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.

Development of a mechanism-based biomarker for Dioscorea bulbifera L. exposure and hepatotoxicity in rats.

BACKGROUND: Dioscorea bulbifera L. (DBL) is a common herbal medicine where furanoterpenoid diosbulbin B (DSB) is a major component responsible for its hepatotoxicity. The metabolic oxidation of the furan moiety of DSB, resulting in covalent binding to hepatic protein, is considered to initiate its liver injury. PURPOSE: We aimed to develop a mechanism-based plasma protein adduction-based biomarker to determine DBL exposure and to predict the onset of hepatotoxicity induced by DBL. METHODS: Rats were intragastrically treated with DBL extract, and the plasma samples were collected. Plasma ALT and AST were measured with commercial kits. Plasma protein modification was determined by immunoblot assay. Assessment of DSB-induced protein adduction was achieved by LC-MS/MS analysis of complete proteolytic digestion of adducted protein to pyrroline derivative A4 using pronase enzyme. The structure of the resulting pyrroline derivatives was confirmed by NMR. RESULTS: Plasma protein of rats treated with DBL extract was covalently modified by the metabolite of DSB. Pyrroline derivative A4 was detected in proteolytic digestion of plasma obtained from rats administered DBL extract. The protein adduction elevated with the increase in the dosage of DBL extract. A detectable level of plasma was observed 10 days after withdrawal of DBL extract post 30-day continuous administration. In addition, the elevation trend of plasma ALT was found to be proportional to the accumulation trend of pyrroline derivative A4. CONCLUSION: DSB-derived plasma protein adduction correlated well with the exposure of DBL in rats. The protein adduction may be used as a good biomarker for diagnosis of DBL-induced liver injury and a useful indicator for DBL medication plans.

Antimalarial properties and molecular docking analysis of compounds from Dioscorea bulbifera L. as new antimalarial agent candidates.

BACKGROUND: At present, the emergence and spread of antimalarial drug resistance has become a significant problem worldwide. There has been a challenge in searching for natural products for the development of novel antimalarial drugs. Therefore, this study aims to evaluate compounds from Dioscorea bulbifera responsible for antimalarial properties and investigate potential interactions of the compounds with Plasmodium falciparum lactate dehydrogenase (PfLDH), an essential glycolytic enzyme in the parasite's life cycle. METHODS: An in vitro study of antimalarial activity against chloroquine (CQ)-resistant Plasmodium falciparum (K1 strain) and CQ-sensitive P. falciparum (3D7 strain) was performed using the 3H-hypoxanthine uptake inhibition method. The cytotoxic effects of the pure compounds were tested against Vero cells using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The interactions of the compounds with the PfLDH active site were additionally investigated using a molecular docking method. RESULTS: Quercetin (6) exhibited the highest antimalarial activity against the P. falciparum K1 and 3D7 strains, with IC50 values of 28.47 and 50.99 µM, respectively. 2,4,3',5'-Tetrahydroxybibenzyl (9), 3,5-dimethoxyquercetin (4) and quercetin-3-O-ß-D-galactopyranoside (14) also possessed antimalarial effects against these two strains of P. falciparum. Most pure compounds were nontoxic against Vero cells at a concentration of 80 µg/ml, except for compound 9, which had a cytotoxic effect with a CC50 value of 16.71 µM. The molecular docking results indicated that 9 exhibited the best binding affinity to the PfLDH enzyme in terms of low binding energy (- 8.91 kcal/mol) and formed strong hydrogen bond interactions with GLY29, GLY32, THR97, GLY99, PHE100, THR101 and ASN140, amino acids as active sites. In addition, 6 also possessed remarkable binding affinity (- 8.53 kcal/mol) to PfLDH by interacting with GLY29, ILE31, ASP53, ILE54, THR97 and THR101. CONCLUSION: Quercetin is a major active compound responsible for the antimalarial activity of D. bulbifera and is an inhibitor of PfLDH. These findings provide more evidence to support the traditional use of D. bulbifera for malaria treatment. Structural models of its interactions at the PfLDH active site are plausibly useful for the future design of antimalarial agents.

Dioscorea bulbifera L.-induced hepatotoxicity and involvement of metabolic activation of furanoterpenoids.

The rhizome of Dioscorea bulbifera L. (DBL) is a popular traditional herb in the treatment of goiters, breast lumps, and tumors. Unfortunately, DBL can give rise to severe hepatotoxicity. More than 100 cases of liver injury, due to the usage of DBL in China, have been reported in the past half-century. The main toxic components of DBL are furanoditerpenoids diosbulbin B (DSB) as well as 8-epidiosbulbin E (EEA). This toxic effect requires metabolic oxidation of the furan ring mediated by cytochrome P450 enzymes, and the P450 3A subfamily is the main enzyme responsible for the reported hepatotoxicity. cis-Enedial intermediates resulting from furan ring oxidation can react with nucleophilic sites of macromolecules, such as protein and DNA, which may trigger the toxicities. This review illustrates the liver injury induced by DBL including metabolic activation of DSB and EEA, the essential components responsible for DBL-induced hepatotoxicity, along with biochemical mechanisms of their toxic actions. It will facilitate the development of approaches to prevent and intervene in liver injury induced by DBL for its safe use in clinical practice.

Sensitive bromine-based screening of potential toxic furanoids in Dioscorea bulbifera L.

Numerous furanoids have been reported to be toxic, and many of them were found in herbal medicines. Toxicities of furanoids are suggested to result from the generation of cis-enedials via biotransformation. The detection of the electrophilic metabolic intermediates is a challenge. Earlier, we developed a selective approach to screen potential toxic furanoids, through which we found two major furanoids, diosbulbin B and 8-epidiosbulbin E acetate, in Dioscorea bulbifera L., a known furanoid-containing and hepatotoxic herbal medicine. In the present study, we improved the approach to analyze furanoids in D. bulbifera L., which allowed us to detect additional six potential furanoids, including diosbulbin A, diosbulbin D, diosbulbin E, diosbulbin F, diosbulbin M, and diosbulbin D glycoside. The achievements of this study enhanced the sensitivity to screen potential toxic furanoids through elevating S/N values by approximately 3 times. This will facilitate the understanding of mechanisms of toxic actions of D. bulbifera L. and other furanoid-containing toxic herbal medicines.

The role of Ntcp, Oatp2, Bsep and Mrp2 in liver injury induced by Dioscorea bulbifera L. and Diosbulbin B in mice.

Dioscorea bulbifera L. (DB) is a traditional Chinese herb used in thyroid disease and cancer. However, the clinical use of DB remains a challenge due to its hepatotoxicity, which is caused, in part, by the presence of Diosbulbin B (DIOB), a toxin commonly found in DB extracts. As abnormal expression of hepatobiliary transporters plays an important role in drug-induced liver injury, we assessed the hepatotoxicity induced by DB and DIOB, and explored their impacts on hepatobiliary transporter expression levels. Following liquid chromatography-tandem mass analysis of the DIOB content of DB extract, male ICR mice were randomly orally administered DB or DIOB for 14days. Liver injury was assessed by histopathological and biochemical analysis of liver fuction. The levels of transporter protein and mRNA were determined by western blotting and real-time PCR. Liver function and histopathological analysis indicated that both DB and DIOB could induce liver injury in mice, and that DIOB might be the primary toxic compound in DB. Moreover, down-regulation of Mrp2 blocked the excretion of bilirubin, glutathione disulfide, and bile acids, leading to the accumulation of toxic substrates in the liver and a redox imbalance. We identified down-regulated expression of Mrp2 as potential factors linked to increased serum bilirubin levels and decreased levels of glutathione in the liver and increased liver injury severity. In summary, our study indicates that down-regulation of Mrp2 represents the primary mechanism of DB- and DIOB-induced hepatotoxicity, and provides insight into novel therapies that could be used to prevent DB- and DIOB-mediated liver injury.

ESTUDIO ETNOBOTÁNICO DE LA PAPA DE AIRE (Dioscorea bulbifera L) EN DONOSO (COLÓN, REPÚBLICA DE PANAMÁ) / ETHNO-BOTANICAL STUDY OF AIR POTATO (Dioscorea bulbifera L) IN DONOSO (COLÓN, REPUBLIC OF PANAMÁ)

Con el objetivo de conocer y rescatar la historia, usos y manejo dado a Dioscorea bulbifera L. por las comunidades campesinas del distrito de Donoso (provincia de Colón, Panamá) se llevó a cabo un estudio etnobotánico en el primer semestre de 2012. El mismo se desarrolló a partir de grupos focales, recorridos de campo y entrevistas semiestructuradas a personajes clave (ancianos, curanderos y personas que cultivan D. bulbifera). Se realizaron cinco grupos focales y 11 entrevistas semiestructuradas, abordando aspectos relativos a historia, nombres, manejo tradicional, usos y formas de consumo de la papa de aire en la región. Como resultados destacados se tiene que D. bulbifera es una especie de muy vieja presencia en las comunidades, teniendo como uso principal la alimentación humana. Igualmente, los agricultores dan cuenta de la importancia de esta especie como alimento altamente nutritivo y con algunos usos medicinales. La información recabada sugiere un conocimiento erosionado respecto de esta especie, lo cual se refleja en el nivel de conocimiento de su manejo y la disminución de su cultivo. No obstante, el conocimiento rescatado resulta de gran utilidad para el establecimiento de ensayos que se orienten a la sistematización de prácticas de cultivo de esta especie.

In order to know and rescue the history, uses and management of Dioscorea bulbifera L. given by peasant communities in the district of Donoso (Colón Province, Panamá) an ethno-botanical study was conducted in the first semester 2012. The study was developed from focus groups, field observations and semi-structured interviews to key figures (elders, healers and people who plant D. bulbifera). Five focus groups and eleven semi-structured interviews were conducted, addressing aspects of history, names, traditional management, uses and forms of consumption of air potatoes in the region. Some outstanding results, demonstrate that Dioscorea bulbifera is a species of very old presence in the communities, used mainly for human consumption. Furthermore, farmers report the importance of this species as a highly nutritious food and having some medicinal uses. The information gathered suggests an eroded knowledge about this species, which is reflected in the level of knowledge of its handling and decreased cultivation. However, the rescued knowledge is useful for establishing essays that aim to systematize practices for cultivation of this species.

Diosbulbin B-induced liver injury in mice and its mechanism.

Dioscorea bulbifera L., a commonly used medicinal plant in China, is reported to induce hepatotoxicity. The present study is undertaken to investigate the hepatotoxicity induced by diosbulbin B (DB), a diterpene lactone isolated from D. bulbifera L., and to further explore its underlying mechanism. DB was administered to mice at the doses of 0, 16, 32, and 64 mg/kg once daily for 12 consecutive days. Liver injury induced by DB was evidenced by the increased activity of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). Liver histological evaluation showed that the mice treated with DB exhibited liver damage with the swelling of hepatocytes. Further results showed that the amount of malondialdehyde (MDA) in the liver was increased in mice treated with DB, while the glutathione amount and the enzymatic activity of glutathione peroxidase (GPx), glutathione-S-transferase (GST), copper/zinc-superoxide dismutase (CuZn-SOD), manganese-SOD (Mn-SOD), and catalase (CAT) were all decreased. DB also decreased the gene expression of CuZn-SOD and CAT. Taken together, our results indicate that oral administration of DB for 12 consecutive days can lead to the oxidative stress liver injury in mice.

Antioxidant and SGC-7901 cell inhibition activities of Rhizoma Dioscoreae bulbiferae. ethanol extracts.

The objective of this research was to study the pharmacology of Dioscorea bulbifera L. on antioxidant and anticancer activity. Alcohol extracts of Dioscorea bulbifera L. were made out by different concentration alcohol; they were tested by Hydroxyl radical scavenging test, reducing capacity test and total antioxidant capacity test. In the anticancer test, MTT test was used to study the inhibition rate. The results told that 70% ethanol extracts could scavenge most DPPH· at 2 mg/ml. The rate was 55.2%; 80% ethanol extract could clear the most ·OH. The clearance rate was 51.2%. 80% ethanol crude extracts possessed the strongest reducing ability per gram of the extract equal to 49.3 µmol Fe(2 +). Different concentrations of the extracts could inhibit the proliferation of line SGC-7901, and with the concentration increased, the inhibition rate was gradually increased.