Antimicrobial and in silico studies of the triterpenoids of Dichapetalum albidum

Mary A Chama; Godwin A Dziwornu; Elizabeth Popli; Eduard Mas-Claret; Beverly Egyir; Daniel M Ayine-Tora; Kofi B-A Owusu; David G Reid; Dorcas Osei-Safo; Melinda Duer; Dulcie Mulholland; Andreas Bender

doi:10.1016/j.heliyon.2023.e18299

Antimicrobial and in silico studies of the triterpenoids of Dichapetalum albidum

Heliyon. 2023 Jul 14;9(7):e18299. doi: 10.1016/j.heliyon.2023.e18299. eCollection 2023 Jul.

Affiliations

¹ Department of Chemistry, SPMS, CBAS, University of Ghana, Ghana.
² Yusuf Hamied Department of Chemistry, University of Cambridge, United Kingdom.
³ Royal Botanic Gardens, Kew, Richmond, TW9 3AQ, United Kingdom.
⁴ Department of Bacteriology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Ghana.
⁵ Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Ghana.
⁶ Department of Chemistry, University of Surrey, Guildford, United Kingdom.

Abstract

Here we report a new polyhydroxylated triterpene, 2β,6β,21α-trihydroxyfriedelan-3-one (4) isolated from the root and stem bark of Dichapetalum albidum A. Chev (Dichapetalaceae), along with six known triterpenoids (1-3, 5, 6, 8), sitosterol-3β-O-D-glucopyranoside (9), a dipeptide (7), and a tyramine derivative of coumaric acid (10). Friedelan-3-one (2) showed an antimicrobial activity (IC₅₀) of 11.40 μg/mL against Bacillus cereus, while friedelan-3α-ol (1) gave an IC₅₀ of 13.07 μg/mL against Staphylococcus aureus with ampicillin reference standard of 19.52 μg/mL and 0.30 μg/mL respectively. 3β-Acetyl tormentic acid (5) showed an IC₅₀ of 12.50 μg/mL against Trypanosoma brucei brucei and sitosterol-3β-O-d-glucopyranoside (9) showed an IC₅₀ of 5.06 μg/mL against Leishmania donovani with respective reference standards of IC₅₀ 5.02 μg/mL for suramin and IC₅₀ 0.27 μg/mL for amphotericin B. Molecular docking of the isolated compounds on the enzyme glucose-6-phosphate dehydrogenase (G6PDH) suggested 3β-acetyl tormentic acid (5) and sitosterol-3β-O-D-glucopyranoside (9) as plausible inhibitors of the enzyme in accordance with the experimental biological results observed.

Keywords: 2β, 6β, 21α-trihydroxyfriedelan-3-one; 3β-acetoxy-2α,19β-dihydroxy-urs-12-en-28-oic acid; Dichapetalum albidum; Glucose-6-phosphate dehydrogenase; Leishmania donovani; Trypanosoma brucei brucei.