Alterbutenolide, a new butenolide derivative from a sponge-derived fungus Alternaria alternata I-YLW6-1

Abstract

Alterbutenolide (1), a new butenolide derivative with a long-chain aliphatic acid substitution, together with seven known phenolic compounds i.e. alternariol (2), asperigillol B (3), p-hydroxyphenylacetic acid (4), p-hydroxyphenylethyl alcohol (5), methyl p-hydroxyphenyl acetate (6), 2-(4-hydroxyphenyl)ethyl acetate (7), and 5,6-dihydro-4-methyl-2H-pyran-2-one (8), was isolated from the cultures of a sponge-derived fungus Alternaria alternata I-YLW6-1. The structure of 1 was established on the basis of HR-MS, 1D and 2D NMR, as well as by comparison of the optical rotation data with the literature reported. Compounds 2 and 3 showed significant to moderate inhibitory activities against three harmful microalgae with IC₅₀ values from 3.0 to 36.2 μg/mL, whereas compound 1 only displayed moderate inhibition against Chattonella marina with IC₅₀ value of 34.6 μg/mL. Meanwhile, compounds 3 and 4 showed weak toxicity against brine shrimp larvae with LC₅₀ values >100 μg/mL.

Keywords:

• Marine fungus
• Alternaria alternata I-YLW6-1
• alterbutenolide
• butenolide
• anti-microalgal activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the Yantai Program for Science and Technique Development (2018ZHGY065) and the Shandong Program for Science and Technology Development of Traditional Chinese Medicine (2020M037).