Botany Department, Faculty of Science, Aswan University, Aswan, 81528, Egypt.
Arch Microbiol. 2020 Dec;202(10):2679-2687. doi: 10.1007/s00203-020-01989-7. Epub 2020 Jul 28.
Some studies focused on metabolic relationships between plants and their endophytic bacterial associates, and more research is required to generate critical evidence for these relationships. In the current interest, we tried to confirm the relationship between the traditional medicinal plant, Calotropis procera (Aiton) W.T. Aiton, and its associated endophytes, Bacillus siamensis and Bacillus amyloliquefaciens, as the first matching study regarding the production of bioactive secondary metabolites from the plant vis-a-vis its bacterial endophytes.Secondary metabolites of both the plant and its endophytic bacteria were extracted using different solvents, e.g., water, methanol, and ethyl acetate. All extracts exhibited high quantities of phenolics, flavonoids, tannins, and saponins. In addition, they showed significant antioxidant capacity which was found to be positively correlated with total phenolic contents. The highest total antioxidant capacity (99.28 ± 0.0 mg AA equivalent/g extract) was measured for the aqueous extract of B. siamensis.Antibacterial activity of the different extracts was evaluated against certain pathogenic bacteria, i.e., Escherichia coli, Klebsiella pneumoniae, Streptococcus agalactiae, Salmonella typhi, Serratia marcescens, and Staphylococcus aureus. It was strikingly found that the broadest antibacterial spectrum was revealed by extracts of both C. procera and its endophytic B. siamensis. Interestingly, antibacterial activity was significantly correlated to phenolic and flavonoid contents.
一些研究集中在植物与其内生细菌之间的代谢关系上，需要更多的研究来为这些关系提供关键证据。在当前的研究兴趣中，我们试图确认传统药用植物长春花（Calotropis procera（Aiton）W.T. Aiton）与其相关内生细菌，解淀粉芽孢杆菌和苏云金芽孢杆菌之间的关系，作为关于植物与其细菌内生菌产生生物活性次生代谢产物的第一个匹配研究。使用不同的溶剂，如水、甲醇和乙酸乙酯，从植物及其内生细菌中提取次生代谢产物。所有提取物均显示出大量的酚类、类黄酮、单宁和皂苷。此外，它们表现出显著的抗氧化能力，与总酚含量呈正相关。解淀粉芽孢杆菌的水提取物的总抗氧化能力最高（99.28±0.0 mg AA 当量/g 提取物）。不同提取物对某些致病菌（大肠杆菌、肺炎克雷伯菌、无乳链球菌、伤寒沙门氏菌、粘质沙雷氏菌和金黄色葡萄球菌）的抗菌活性进行了评估。令人惊讶的是，长春花及其内生解淀粉芽孢杆菌的提取物显示出最广泛的抗菌谱。有趣的是，抗菌活性与酚类和类黄酮含量显著相关。
