Pestalotiopisorin B,a new isocoumarin derivative from the mangrove endophytic fungus Pestalotiopsis sp. HHL101

Abstract

A new isocoumarin derivative pestalotiopisorin B (1), along with six known compounds, (R)-(-)- mellein methyl ether (2), pestalotiopyrone G (3), (R)-mevalonolactone (4), pestalotiollides A–B (5–6) and pestalotiopsol A(7) were isolated from Pestalotiopsis sp., an endophytic fungus obtained from Chinese mangrove plant Rhizophora stylosa. Their structures were elucidated unambiguously by the comprehensive analysis of extensive spectroscopic data. Compound 1 exhibited modest antibacterial activity against Escherichia coli and Pseudomonas aeruginosa with 12.5?μg/ml, 50?μg/ml, respectively. Compound 4 showed moderate calcineurin inhibitory activity towards p-nitrophenyl phosphate (IC₅₀ =134.29?±?5.377?μM).     

Previously undescribed benzoxepins with bioactivities against inducible pro-inflammatory cyclooxygenase and lipoxygenase from Rhizophora annamalayana Kathir

Two unprecedented benzoxepins were obtained from the ethyl acetate fraction of the leaves of Rhizophora annamalayana Kathir, and characterized as 4-(11-(hydroxymethyl)-10-methylpentan-2-yl)-4, 5-dihydrobenzo[c]oxepin-1(3H)-one (1) and (E)-methyl-14-hydroxy-4-(11-(5-hydroxy-1-oxo-3,4,5-tetrahydrobenzo[c]oxepin-4-yl)ethyl)-10-methylhept-11-enoate (2). The benzoxepin 2 exhibited greater 1, 1-diphenyl-2-picrylhydrazyl and 2, 2′-azino-bis-3 ethylbenzothiozoline-6-sulfonic acid diammonium radical scavenging assays (IC₅₀ 0.68 and 0.84 mg/mL, respectively) than those recorded with 1 (IC₅₀ 0.70 and 0.89 mg/mL, respectively). The tetrahydrobenzo[c]oxepin analogue (2) exhibited significantly great cyclooxygenase-2 and 5-lipoxygenase inhibitory properties (IC₅₀ 0.87 and 0.94 mg/mL, respectively), while compared with its dihydrobenzo[c]oxepin-1(3H)-one isoform (1) (IC₅₀ 1.16 and 1.64 mg/mL, respectively). The dihydrobenzo[c]oxepin-1(3H)-one isoform (2) exhibited significantly greater selectivity index (~2) than synthetic ibuprofen (0.44) (p < 0.05), which attributed the higher anti-inflammatory selectivity of the former against inducible pro-inflammatory cyclooxygenase-2 than its constitutive isoform (cyclooxygenase-1). No significant difference in 5-lipoxygenase (5-LOX) inhibitory activities were apparent between compound 2 (IC₅₀ 0.94 mg/mL) and synthetic ibuprofen (IC₅₀ 0.93 mg/mL).     

来源湛江红树内生真菌的二氢异香豆素及其抑菌活性

为了研究湛江红树(Rhizophora apiculata)植物内生真菌Fusarium sp.F67和B42的二氢异香豆素类次级代谢产物及其抑菌活性,采用色谱技术对菌株F67和B42的代谢产物进行分离纯化,确认所得化合物的结构为:3,6,8-三羟基-3,4,5,7-四甲基-3,4-二氢异香豆素(sclerotinin A)(1),二氢橘霉素(2)、5-甲基蜂蜜曲菌素(3)、5-羧基蜂蜜曲菌素(4)、4-羟基蜂蜜曲菌素(5)和蜂蜜曲菌素(6),并利用滤纸片琼脂扩散法检测化合物对7种常见致病菌的抑菌活性。在1.0 g/L质量浓度下化合物1~4对受试菌株的抑菌圈范围为5.1~11.0 mm,其中化合物4的抑菌活性相对较强,抑菌谱相对较广,可为挖掘新型抗菌药物的研究提供补充。