Antimicrobial Acylphloroglucinol Meroterpenoids and Acylphloroglucinols from Dryopteris crassirhizoma

Planta Med. 2023 Mar;89(3):295-307. doi: 10.1055/a-1917-7910. Epub 2022 Aug 3.

Abstract

Ten novel meroterpenoids, dryoptins/11″-epi-dryoptins A~E (1: ~10: ) with an unprecedented skeleton consisting of dimeric or trimeric acylphloroglucinols and dehydrotheonelline, two undescribed acylphloroglucinol-nerolidol meroterpenoids (11: ~12: ), and ten known acylphloroglucinol derivatives (13: ~22: ), were isolated from D. crassirhizoma. The novel structures including absolute configurations were established by comprehensive spectroscopic analyses and quantum chemical electronic circular dichroism (ECD) calculations. A biosynthetic pathway of 1: ~10: was assumed. The trimeric acylphloroglucinol meroterpenoids 7: /8: showed significant antifungal activity against standard Candida albicans with a MIC50 value of 1.61 µg/mL [fluconazole (FLC): 3.41 µg/mL], and when combined with FLC, the principal components 20: and 21: exhibited strong antifungal activities against FLC-resistant C. albicans with MIC50 values of 8.39 and 7.16 µg/mL (FLC: > 100 µg/mL), respectively. Moreover, compounds 2, 5: /6, 18, 19: , and 21: exhibited inhibitory effects against several pathogenic fungi and bacteria, with MIC50 values of 6.25 ~ 50 µg/mL.

MeSH terms

  • Antifungal Agents* / pharmacology
  • Candida albicans
  • Circular Dichroism
  • Dryopteris* / chemistry
  • Fluconazole / pharmacology

Substances

  • Antifungal Agents
  • Fluconazole

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