Data from: Biotransformation of labdane and halimane diterpenoids by two filamentous fungi strains

Biotransformation of natural products by filamentous fungi is a powerful and effective approach to achieve derivatives with valuable new chemical and biological properties. Despite diterpenoid substrates exhibit good susceptibility towards fungi enzymes, there have been no studies concerning the microbiological transformation of halimane-type diterpenoids up to now. In this work, we investigated the capability of Fusarium oxysporum (a fungus isolated from the rhizosphere of Senna spectabilis) and Myrothecium verrucaria (an endophyte) to transform halimane (1) and labdane (2) acids isolated from Hymenaea stigonocarpa (Fabaceae). Feeding experiments resulted in the production of six derivatives, including hydroxy, oxo, formyl, and carboxy analogues. Incubation of 1 with F. oxysporum afforded 2-oxo-derivative (3), while bioconversion with M. verrucaria provided 18,19-dihydroxy (4), 18-formyl (5), and 18-carboxy (6) bioproducts. Transformation of substrate 2 mediated by F. oxysporum produced a 7-hydroxy (7) derivative, whilst M. verrucaria yielded 7- (7) and 3-hydroxy (8) metabolites. Unlike F. oxysporum, which showed a preference to transform ring B, M. verrucaria, exhibited the ability to hydroxylate both rings A and B from substrate 2. Additionally, compounds 1–8 were evaluated for inhibitory activity against Hr-AChE and Hu-BChE enzymes through ICER-IT-MS/MS assay.

利用丝状真菌进行天然产物的生物转化，是制备兼具新颖化学结构与珍贵生物活性衍生物的高效可靠途径。尽管二萜类底物对真菌酶类展现出良好的可转化性，但截至目前，尚无关于halimane型（halimane-type）二萜类化合物的微生物转化研究报道。本研究考察了尖孢镰刀菌（Fusarium oxysporum，分离自美丽决明（Senna spectabilis）根际）与疣孢漆斑菌（Myrothecium verrucaria，一种内生真菌）对分离自显脉孪叶豆（Hymenaea stigonocarpa，豆科Fabaceae）的halimane型二萜酸（化合物1）以及劳丹烷型（labdane-type）二萜酸（化合物2）的转化能力。底物饲喂实验共得到6种衍生物，涵盖羟基、氧代、甲酰基与羧基类结构类似物。将化合物1与尖孢镰刀菌共孵育，获得2-氧代衍生物（化合物3）；而疣孢漆斑菌介导的生物转化则得到18,19-二羟基（化合物4）、18-甲酰基（化合物5）与18-羧基（化合物6）产物。尖孢镰刀菌介导的化合物2转化反应生成7-羟基衍生物（化合物7）；疣孢漆斑菌则获得7-羟基（化合物7）与3-羟基（化合物8）代谢产物。与偏好转化B环的尖孢镰刀菌不同，疣孢漆斑菌可对化合物2的A环与B环均进行羟基化修饰。此外，本研究通过ICER-IT-MS/MS实验，对化合物1至8开展了针对Hr-AChE与Hu-BChE酶的抑制活性评价。