Sanguansermsri Donruedee, Sanguansermsri Phanchana, Buaban Kittisak, Choommongkol Vachira, Akekawatchai Chareeporn, Charoensri Noree, Fraser Ian, Wongkattiya Nalin
Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
Center of Excellence in Medical Biotechnology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
BMC Complement Med Ther. 2024 May 2;24(1):180. doi: 10.1186/s12906-024-04480-8.
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.
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.
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 CC 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.
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.
薯蓣（Dioscorea bulbifera Linn.）在泰国已被用于伤口护理。然而，需要对其抗菌活性进行全面评估。本研究旨在调查薯蓣提取物对皮肤相关细菌的抗菌效果，并分离和鉴定其活性抗菌剂黄独素。
将风干的薯蓣珠芽粉碎，用己烷、二氯甲烷、乙酸乙酯、甲醇、乙醇和蒸馏水提取；真空过滤；浓缩；冻干；并储存在-20℃。使用微量稀释技术评估提取物对几种皮肤相关细菌的抗菌活性。采用薄层色谱（TLC）生物自显影法鉴定提取物中的活性化合物，通过柱色谱对其进行分离，并用制备型TLC进行纯化。使用核磁共振（NMR）分析纯化化合物的化学结构。在Vero细胞中评估提取物及其活性化合物的细胞毒性。
与其他提取物相比，乙酸乙酯提取物对细菌表现出明显的抑菌圈。因此，乙酸乙酯层中的薯蓣乙酸乙酯提取物用于后续分析。薯蓣提取物表现出抗菌活性，最低抑菌浓度（MIC）为0.78 - 1.56mg/mL。通过TLC - 生物自显影鉴定的一种活性化合物表现出增强的抗菌活性，MIC为0.02 - 0.78mg/mL。NMR分析确定该生物活性化合物为黄独素。薯蓣提取物和含黄独素的组分对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌（MRSA）和表皮葡萄球菌均表现出强效抗菌活性。含黄独素的组分对Vero细胞表现出低细胞毒性，CC值为0.41±0.03mg/mL。这些值低于MIC值，表明该组分比最初的乙酸乙酯提取物更安全。
薯蓣提取物及其生物活性成分黄独素对包括MRSA在内的皮肤相关细菌葡萄球菌表现出显著的抗菌活性。由于其强效的抗菌作用和低细胞毒性，黄独素具有作为治疗皮肤感染的辅助治疗剂的潜力。
