Engineering Research Center of Medical Biotechnology, Guizhou Medical University, Guiyang, 550025, Guizhou, China; Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, 550025, Guizhou, China; School of Biology and Engineering, Guizhou Medical University, Guiyang, 550025, Guizhou, China; Immune Cells and Antibody Engineering Research Center of Guizhou Province, China; Key Laboratory of Environmental Pollution Monitoring and Disease Control, China Ministry of Education (Guizhou Medical University), Guiyang, 550025, Guizhou, China.
Engineering Research Center of Medical Biotechnology, Guizhou Medical University, Guiyang, 550025, Guizhou, China; School of Biology and Engineering, Guizhou Medical University, Guiyang, 550025, Guizhou, China.
J Ethnopharmacol. 2021 May 10;271:113895. doi: 10.1016/j.jep.2021.113895. Epub 2021 Jan 30.
Ginkgo biloba L. fruit, also known as Bai Guo, Ya Jiao Zi (in pinyin Chinese), and ginkgo nut (in English), has been used for many years as an important material in Chinese traditional medicine to treat coughs and asthma and as a disinfectant, as described in the Compendium of Materia Medica (Ben Cao Gang Mu, pinyin in Chinese), an old herbal book. Ginkgo nuts are used to treat phlegm-associated asthma, astringent gasp, frequent urination, gonorrhoea and turgidity; consumed raw to reduce phlegm and treat hangovers; and used as a disinfectant and insecticide. A similar record was also found in Sheng Nong's herbal classic (Shen Nong Ben Cao Jing, pinyin in Chinese). Recent research has shown that Ginkgo biloba L. exocarp extract (GBEE) can unblock blood vessels and improve brain function and exhibits antitumour and antibacterial activities.
To investigate the inhibitory effect of Ginkgo biloba L. exocarp extract (GBEE) on methicillin-resistant S. aureus (MRSA) biofilms and assess its associated molecular mechanism.
The antibacterial effects of GBEE on S. aureus and MRSA were determined using the broth microdilution method. The growth curves of bacteria treated with or without GBEE were generated by measuring the CFU (colony forming unit) of cultures at different time points. The effects of GBEE on bacterial biofilm formation and mature biofilm disruption were determined by crystal violet staining. Quantitative polymerase chain reaction (qPCR) was used to measure the effects of GBEE on the gene expression profiles of MRSA biofilm-related factors at 6, 8, 12, 16 and 24 h.
The minimum inhibitory concentration (MIC) of GBEE on S. aureus and MRSA was 4 μg/mL, and the minimum bactericidal concentration (MBC) was 8 μg/ml. Moreover, GBEE (4-12 μg/mL) inhibited S. aureus and MRSA biofilm formation in a dose-dependent manner. Interestingly, GBEE also destroyed mature biofilms of S. aureus and MRSA at 12 μg/ml. The expression of the MRSA biofilm-associated factor icaA and sarA were downregulated after 6 h of treatment with GBEE, while sigB was downregulated after 12 h. MeanwhileMeanwhile, icaR was upregulated at 12 h. In addition, GBEE also downregulated the virulence gene hld and inhibited the synthesis of staphyloxanthin.
GBEE has excellent antibacterial effects against S. aureus and MRSA and inhibits their biofilm-forming ability by altering related gene expression.
银杏白果，又名鸭脚子（拼音）、银杏坚果（英文），在《本草纲目》（Ben Cao Gang Mu，拼音）等古老的草药书中，作为中国传统医学的重要材料，多年来一直用于治疗咳嗽和哮喘以及作为消毒剂。银杏坚果可用于治疗痰喘、涩喘、尿频、淋病和肿胀；生用可化痰解酒；用作消毒剂和杀虫剂。在《神农本草经》（Shen Nong Ben Cao Jing，拼音）中也有类似的记载。最近的研究表明，银杏外种皮提取物（GBEE）能疏通血管、改善脑功能，具有抗肿瘤和抗菌活性。
研究银杏外种皮提取物（GBEE）对耐甲氧西林金黄色葡萄球菌（MRSA）生物膜的抑制作用，并评估其相关的分子机制。
采用肉汤微量稀释法测定 GBEE 对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌的抑菌作用。通过不同时间点测量培养物的 CFU（集落形成单位）生成细菌生长曲线。结晶紫染色法测定 GBEE 对细菌生物膜形成和成熟生物膜破坏的影响。采用定量聚合酶链反应（qPCR）测定 GBEE 对耐甲氧西林金黄色葡萄球菌生物膜相关因子基因表达谱在 6、8、12、16 和 24 小时的影响。
GBEE 对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌的最小抑菌浓度（MIC）为 4μg/ml，最小杀菌浓度（MBC）为 8μg/ml。此外，GBEE（4-12μg/ml）呈剂量依赖性抑制金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌的生物膜形成。有趣的是，GBEE 还能破坏金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌成熟生物膜，浓度为 12μg/ml。GBEE 处理 6 小时后，MRSA 生物膜相关因子 icaA 和 sarA 的表达下调，12 小时后 sigB 下调。同时，icaR 在 12 小时上调。此外，GBEE 还下调了毒力基因 hld 并抑制了金葡素的合成。
GBEE 对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌具有良好的抗菌作用，并通过改变相关基因表达抑制其生物膜形成能力。
