Ruma Karmakar, Sunil Kumar, Prakash Harischandra Sripathy
Department of Studies in Biotechnology, University of Mysore , Manasagangotri, Mysore, Karnataka , India.
Pharm Biol. 2014 Jun;52(6):665-76. doi: 10.3109/13880209.2013.863950. Epub 2014 Mar 17.
Endophytes colonizing medicinal plants are diverse, constituting a rich bioresource for novel natural products.
Myrothecium sp. isolate M1-CA-102 was the most promising among the 16 Myrothecium isolates screened. The bioactive potential of the crude extract from the Calophyllum apetalum Willd. endophytic Myrothecium sp. (Alb. & Schwein.) Ditmar (Incertae sedis) isolate M1-CA-102 and its thin layer chromatography (TLC) fractions were screened based on antioxidant, anti-inflammatory, antimicrobial activities, and cytotoxicity.
The antioxidant activity was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging capacities. Further, 15-lipoxygenase (15-LOX) and human cyclooxygenase-2 (COX-2) inhibition were assessed at different concentrations (25, 50, and 100 μg/mL for the crude extract, 5, 25, and 50 μg/mL for the TLC fractions). DNA-nicking assay as an indicator of the capacity of extracts to scavenge hydroxyl radical was recorded at a concentration of 50 μg/mL. Cell cytotoxicity was recorded by colorimetric 3-(4,5-dimethylthylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Antibacterial (Bacillus subtilis) and anti-Candida (Candida albicans) assays were performed by the microdilution method.
The DPPH and ABTS IC50 values of M1-CA-102 extract were 10 and 6 μg/mL compared with 6.1 and 7.03 μg/mL for the positive control quercetin. The cytotoxicity IC50 value of M1-CA-102 extract was 37 μg/mL, while the M-I TLC fraction was 21 μg/mL. The M1-CA-102 extract gave an IC50 value of 58 and 8 μg/mL for 15-LOX and COX-2, respectively. The MIC values for antimicrobial activity for M1-CA-102 extract ranged from 35 to 54 μg/mL, while for the TLC fractions, it ranged from 91 to 515 μg/mL.
The results indicate that Myrothecium M1-CA-102 isolated from C. apetalum is a potential source of natural metabolites of pharmaceutical importance.
定殖于药用植物的内生菌种类多样，构成了新型天然产物的丰富生物资源。
在筛选的16株漆斑菌分离株中，漆斑菌属分离株M1-CA-102最具潜力。对来自无瓣海桑内生漆斑菌（分类地位不确定）分离株M1-CA-102的粗提物及其薄层色谱（TLC）组分的生物活性潜力进行了抗氧化、抗炎、抗菌活性及细胞毒性方面的筛选。
通过1,1-二苯基-2-苦基肼（DPPH）和2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基清除能力测定抗氧化活性。此外，在不同浓度下（粗提物分别为25、50和100μg/mL，TLC组分分别为5、25和50μg/mL）评估15-脂氧合酶（15-LOX）和人环氧化酶-2（COX-2）的抑制情况。以DNA切口试验作为提取物清除羟基自由基能力的指标，在浓度为50μg/mL时进行记录。通过比色法3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）试验记录细胞毒性。采用微量稀释法进行抗菌（枯草芽孢杆菌）和抗念珠菌（白色念珠菌）试验。
M1-CA-102提取物的DPPH和ABTS半数抑制浓度（IC50）值分别为10和6μg/mL，而阳性对照槲皮素的该值分别为6.1和7.03μg/mL。M1-CA-102提取物的细胞毒性IC50值为37μg/mL, 而M-I TLC组分的该值为21μg/mL。M-CA-102提取物对15-LOX和COX-2的IC50值分别为58和8μg/mL。M1-CA-102提取物的抗菌活性最低抑菌浓度（MIC）值范围为35至54μg/mL，而TLC组分的该值范围为91至515μg/mL。
结果表明，从无瓣海桑分离出的漆斑菌M1-CA-102是具有药用重要性的天然代谢产物潜在来源。
