Dos Santos Irailton Prazeres, da Silva Luís Cláudio Nascimento, da Silva Márcia Vanusa, de Araújo Janete Magali, Cavalcanti Marilene da Silva, Lima Vera Lucia de Menezes
Departamento de Micologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco Recife, Brazil ; Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco Recife, Brazil.
Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco Recife, Brazil.
Front Microbiol. 2015 May 7;6:350. doi: 10.3389/fmicb.2015.00350. eCollection 2015.
Endophytic fungi were isolated from healthy leaves of Indigofera suffruticosa Miller, a medicinal plant found in Brazil which is used in folk medicine to treat various diseases. Among 65 endophytic fungi isolated, 18 fungi showed activity against at least one tested microorganism in preliminary screening, and the best results were obtained with Nigrospora sphaerica (URM-6060) and Pestalotiopsis maculans (URM-6061). After fermentation in liquid media and in semisolid media, only N. sphaerica demonstrated antibacterial activity (in Potato Dextrose Broth-PDB and in semisolid rice culture medium). In the next step, a methanolic extract from rice culture medium (NsME) and an ethyl acetate extract (NsEAE) from the supernatant of PDB were prepared and both exhibited antimicrobial activity against Gram-negative and Gram-positive bacteria. The best result was observed against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 1.56 mg/mL and 6.25 mg/mL, respectively, for NsME and MIC and MBC values of 0.39 mg/mL and 3.12 mg/mL, respectively, for NsEAE. This study is the first report about the antimicrobial activity of endophytic fungi residing in I. suffruticosa leaves, in which the fungus N. sphaerica demonstrated the ability to produce bioactive agents with pharmaceutical potential, and may provide a new lead in the pursuit of new biological sources of drug candidates.
内生真菌是从巴西发现的药用植物米氏木蓝健康叶片中分离得到的，该植物在民间医学中用于治疗各种疾病。在分离出的65株内生真菌中，18株真菌在初步筛选中对至少一种受试微生物表现出活性，其中球形黑孢霉（URM - 6060）和黄斑拟盘多毛孢（URM - 6061）取得了最佳结果。在液体培养基和半固体培养基中发酵后，只有球形黑孢霉表现出抗菌活性（在马铃薯葡萄糖肉汤 - PDB和半固体大米培养基中）。下一步，制备了大米培养基的甲醇提取物（NsME）和PDB上清液的乙酸乙酯提取物（NsEAE），二者均对革兰氏阴性菌和革兰氏阳性菌表现出抗菌活性。对金黄色葡萄球菌观察到最佳结果，NsME的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）值分别为1.56 mg/mL和6.25 mg/mL，NsEAE的MIC和MBC值分别为0.39 mg/mL和3.12 mg/mL。本研究是关于米氏木蓝叶片内生真菌抗菌活性的首次报道，其中球形黑孢霉显示出产生具有药用潜力生物活性物质的能力，并可能为寻找新的候选药物生物来源提供新线索。
