Bhuiyan Abdul Ali, Aboul-Soud Mourad A M, Uddin Md Selim, Mazumder Kishor, Akash Arafath Rahman, Aljowaie Reem M, Giesy John P, Agrawal Mohit, Haque Shariful
Department of Pharmacy, Faculty of Science, Pabna University of Science and Technology, Pabna, 6600, Bangladesh.
Center of Excellence in Biotechnology Research, College of Applied Medical Sciences, King Saud University, Riyadh, 11433, Saudi Arabia.
Sci Rep. 2025 Aug 29;15(1):31876. doi: 10.1038/s41598-025-17314-5.
This study investigates the bioactive potential of secondary metabolites produced by endophytic bacteria isolated from Enhydra fluctuans Lour., a medicinal plant known for its antioxidant and antimicrobial properties. Fresh leaves were collected, surface-sterilized, and used to isolate bacterial endophytes. The isolates were identified morphologically and confirmed by 16S rRNA gene sequencing. Metabolites were extracted using ethyl acetate and assessed for antibacterial activity via the disc diffusion method and antioxidant capacity by DPPH radical scavenging assay. GC-MS was used to identify volatile bioactive substances. The isolate showed 91.75% similarity with Pseudomonas campi (NR_181172.1), indicating a distant relationship and suggesting it may represent a novel or uncharacterized taxon. The isolate was mostly sensitive to Ciprofloxacin (5 µg). Its ethyl acetate crude extract showed moderate antibacterial activity against Staphylococcus aureus with a 13.4 ± 0.21 mm inhibition zone at 500 µg/disc, compared to kanamycin (30 µg/disc). Antioxidant activity showed an IC of 61.66 ± 0.33 µg/mL, versus 17.38 ± 0.63 µg/mL for ascorbic acid. GC-MS identified 19 bioactive compounds, with Phenol, 3,5-bis(1,1-dimethylethyl)-, 1,9-Diazaspiro (4,4 )nonane-2,8-dione, and Octacosanol as major constituents. In silico analyses showed that 9,10-anthracenedione, 2-[(tert-butylamino)methylcarbamoyl] exhibited strong antibacterial and antioxidant potential, with high binding affinities to MurD ligase (-9.8 kcal/mol) and myeloperoxidase (-9.6 kcal/mol), respectively. Molecular dynamics (MD) simulations over 100 ns confirmed the stability of these complexes, supported by analyses of RMSD, RMSF, hydrogen bonds, and MMGBSA free energy. Most molecules were predicted to be non-toxic. These findings suggest that 9,10-Anthracenedione exhibits promising binding characteristics, driven by non-covalent interactions, making it a potential candidate for further drug development studies. Our results provide preliminary evidence that endophytic bacteria harbor chemically diverse secondary metabolites, reinforcing their role in natural product-based drug discovery pipelines. While initial findings are promising, Pure compound isolation comprehensive in vivo studies, compound purification, and pharmacokinetic profiling are essential.
本研究调查了从水龙(Enhydra fluctuans Lour.)分离出的内生细菌产生的次生代谢产物的生物活性潜力,水龙是一种以其抗氧化和抗菌特性而闻名的药用植物。采集新鲜叶片,进行表面消毒,并用于分离细菌内生菌。通过形态学鉴定分离株,并通过16S rRNA基因测序进行确认。使用乙酸乙酯提取代谢产物,并通过纸片扩散法评估其抗菌活性,通过DPPH自由基清除试验评估其抗氧化能力。采用气相色谱 - 质谱联用(GC-MS)鉴定挥发性生物活性物质。该分离株与campi假单胞菌(NR_181172.1)的相似度为91.75%,表明亲缘关系较远,提示它可能代表一个新的或未鉴定的分类群。该分离株对环丙沙星(5 μg)大多敏感。其乙酸乙酯粗提物对金黄色葡萄球菌显示出中等抗菌活性,在500 μg/纸片时抑菌圈直径为13.4±0.21 mm,与卡那霉素(30 μg/纸片)相比。抗氧化活性显示IC50为61.66±0.33 μg/mL,而抗坏血酸为17.38±0.63 μg/mL。GC-MS鉴定出19种生物活性化合物,主要成分是3,5 - 双(1,1 - 二甲基乙基)苯酚、1,9 - 二氮杂螺[4.4]壬烷 - 2,8 - 二酮和二十八烷醇。计算机模拟分析表明,9,10 - 蒽二酮、2 - [(叔丁基氨基)甲基氨基甲酰基]分别对MurD连接酶(-9.8 kcal/mol)和髓过氧化物酶(-9.6 kcal/mol)具有很强的抗菌和抗氧化潜力,且结合亲和力高。超过100 ns的分子动力学(MD)模拟证实了这些复合物的稳定性,这得到了均方根偏差(RMSD)、均方根波动(RMSF)、氢键和MMGBSA自由能分析的支持。大多数分子预计无毒。这些发现表明,9,10 - 蒽二酮通过非共价相互作用表现出有前景的结合特性,使其成为进一步药物开发研究的潜在候选物。我们的结果提供了初步证据,表明内生细菌含有化学性质多样的次生代谢产物,强化了它们在基于天然产物的药物发现流程中的作用。虽然初步结果很有前景,但纯化合物分离、全面的体内研究、化合物纯化和药代动力学分析至关重要。