Department of Biochemical Engineering, Engineering Faculty, Universidad Icesi, Cali, Colombia.
Department of Biology, Natural Science Faculty, Universidad Icesi, Cali, Colombia.
Microbiologyopen. 2019 Oct;8(10):e903. doi: 10.1002/mbo3.903. Epub 2019 Jul 12.
Tropical ecosystems hold an extremely diverse array of endophytic fungi, but their potential use still remains to be explored. In this study, we isolated an endophytic fungus from the leaves of Otoba gracilipes, a medicinal tree from a tropical rainforest in Colombia. Following isolation and cultivation, we evaluated its extracellular crude extract for antioxidant activity. Using traditional and molecular methods (ITS1, NL1 regions), the endophyte was identified as Fusarium oxysporum. Fresh spores from the fungal isolate were inoculated in liquid media (potato dextrose broth [PDB] and potato dextrose-yeast extract broth [PDYB]) and centrifuged for recovering extracellular polysaccharides from the exhausted medium after 30 days of cultivation. Crude extracts were recovered, purified, lyophilized, and evaluated for their ability to inactivate the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The extracts obtained from PDB culture media had a 51.5% of scavenging effect on DPPH after 5 min of reaction compared with the extracts from PDBY (26.4%), which suggests a high antioxidant potential of these fungal extracts. Thus, our results suggest other fungi from tropical ecosystems should be explored as potential sources of novel enzymes and other metabolites with bioactivity.
热带生态系统中蕴藏着极其多样的内生真菌，但它们的潜在用途仍有待探索。在这项研究中，我们从哥伦比亚热带雨林中的药用树种 Otoba gracilipes 的叶片中分离出一种内生真菌。经过分离和培养，我们评估了其细胞外粗提取物的抗氧化活性。通过传统和分子方法（ITS1、NL1 区域），确定内生真菌为尖孢镰刀菌。将真菌分离物的新鲜孢子接种于液体培养基（马铃薯葡萄糖肉汤[PDB]和马铃薯葡萄糖酵母提取物肉汤[PDYB]）中，培养 30 天后，离心从耗尽的培养基中回收细胞外多糖。回收、纯化、冻干粗提取物，并评估其灭活自由基 2,2-二苯基-1-苦肼基（DPPH）的能力。与 PDYB（26.4%）相比，PDB 培养基培养物获得的提取物在反应 5 分钟后对 DPPH 的清除率达到 51.5%，这表明这些真菌提取物具有很高的抗氧化潜力。因此，我们的研究结果表明，应进一步探索热带生态系统中的其他真菌，以寻找具有生物活性的新型酶和其他代谢物的潜在来源。
