Three new diterpenoids isolated from Euphorbia nematocypha Hand.-Mazz and their anti-fungal activity

Abstract

Three new diterpenoids, named nematocynine A-C (1-3), together with twelve known compounds (4-15) were isolated from the aerial part of Euphorbia nematocypha Hand.-Mazz (Hereinafter referred to E. nematocypha). Their structures were elucidated by detailed spectroscopic analysis and comparison with literature data. In addition, all the compounds were tested for their anti-candida albicans activities used alone or in combination with fluconazole against sensitive strain and resistant strain in vitro. Wherein only compound 11 shows weak activity against candida albicans resistant strain (MIC₅₀ = 128.15 μg/mL) when used alone. Compounds 1, 4, 7, 8, 9, 10, 12, 13 and 15 in combination with fluconazole showed potent anti-fungal activities (MIC₅₀ = 15 ± 5 μg/mL, FICI = 0.05 ± 0.04) against the Candida albicans resistant strain SC5314-FR. The synergistic effects were weaker against the Candida albicans resistant strain SC5314-FR when the compounds 2, 3, 5 and 14 were combined with fluconazole (FICI = 0.16 ± 0.06).

Graphical Abstract

Keywords:

• Diterpenoid
• Euphorbia nematocypha Hand.-Mazz
• Euphorbiacea
• anti-fungal activity

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (82260682, 81860615), Project of Yunnan Characteristic Plant Screening and R&D Service CXO Platform (2022YKZY001), Applied Basic Research Foundation of Yunnan Province (2018FY001, 2018FA048, 202101AT070864), the Program for Changjiang Scholars and Innovative Research Team in University (IRT_17R94), the Research Innovation Fund for Graduate Students of School of Chemical Science and Technology, Yunnan University(NA), National Key R&D Program of China (2019YFE0109200), and a grant (no. 2021KF004) from YNCUB. Authors thank Advanced Analysis and Measurement Center of Yunnan University for the sample testing service.