Lata Rusi, Gond Surendra Kumar
Department of Botany, MMV, Banaras Hindu University, Varanasi, 221005, India.
Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
Sci Rep. 2025 Jan 15;15(1):2094. doi: 10.1038/s41598-024-84893-0.
The research highlights the importance of exploring endophytic microbiomes of medicinal plants to uncover their potential for secondary metabolite production and their role in the biosynthesis of host-derived compounds. This study was aimed to isolate leaf endophytic bacteria of Rauvolfia serpentina, investigate their antibacterial, antioxidant potentials and detect host-origin compound reserpine using Reverse Phase High-Performance Liquid Chromatography (RPHPLC). Untargeted analysis via Ultra High-Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HRMS/MS) was conducted for profiling main phytochemicals in the leaves and to explore potential bioactive compounds in bacterial extracts. Nine bacterial isolates were obtained from R. serpentina leaves. These isolates exhibited positive results in various biochemical tests including indole production, methyl red, Voges-Proskauer, citrate utilization, catalase and oxidase production, nitrate reduction, oxidative fermentation, and citrate reduction tests. Endophytic isolates RSLB3 and RSLB18 exhibited most potential antibacterial activity against tested human pathogenic bacteria and were identified as Bacillus sp. The extract of RSLB3 and RSLB18 also showed significant antioxidant activity compared to leaf extract. The total phenol content was similar in both these isolates while flavonoids content and DPPH scavenging activity was higher in isolate RSLB3. RPHPLC analysis confirmed the presence of reserpine in bacterial metabolites when compared to a standard reference. UHPLC-HRMS profiling unveiled a diverse range of host-derived compounds and reaction intermediates with known and unknown bioactive properties in leaf extract, RSLB3, and RSLB18. To our knowledge, this is the first study to achieve a comprehensive profiling.
该研究强调了探索药用植物内生微生物群落以揭示其产生次生代谢产物的潜力及其在宿主衍生化合物生物合成中的作用的重要性。本研究旨在分离蛇根木的叶片内生细菌，研究其抗菌、抗氧化潜力，并使用反相高效液相色谱法（RPHPLC）检测宿主来源的化合物利血平。通过超高效液相色谱-高分辨率质谱（UHPLC-HRMS/MS）进行非靶向分析，以分析叶片中的主要植物化学物质，并探索细菌提取物中的潜在生物活性化合物。从蛇根木叶中获得了9株细菌分离株。这些分离株在各种生化试验中均呈现阳性结果，包括吲哚产生、甲基红、Voges-Proskauer、柠檬酸盐利用、过氧化氢酶和氧化酶产生、硝酸盐还原、氧化发酵和柠檬酸盐还原试验。内生分离株RSLB3和RSLB18对测试的人类病原菌表现出最大的抗菌活性，并被鉴定为芽孢杆菌属。与叶片提取物相比，RSLB3和RSLB18的提取物也表现出显著的抗氧化活性。这两种分离株中的总酚含量相似，而分离株RSLB3中的黄酮类化合物含量和DPPH清除活性更高。与标准参考物相比，RPHPLC分析证实细菌代谢产物中存在利血平。UHPLC-HRMS分析揭示了叶片提取物、RSLB3和RSLB18中一系列具有已知和未知生物活性的宿主衍生化合物和反应中间体。据我们所知，这是第一项实现全面分析的研究。
