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Antibacterial Flavonoids and Other Compounds from the Aerial Parts of Vernonia guineensis Benth. (Asteraceae)
Author(s) -
Collins Njonte Wouamba Steven,
Mouthé Happi Gervais,
Nguiam Pouofo Michel,
Tchamgoue Joseph,
Jouda JeanBosco,
Longo Frida,
Ndjakou Lenta Bruno,
Sewald Norbert,
Fogue Kouam Simeon
Publication year - 2020
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.202000296
Subject(s) - chemistry , betulinic acid , lupeol , oleanolic acid , stigmasterol , phytochemical , ursolic acid , antibacterial activity , bacteria , salmonella , escherichia coli , quercetin , traditional medicine , biochemistry , chromatography , biology , medicine , genetics , alternative medicine , pathology , gene , antioxidant
An extensive phytochemical study of the aerial parts of Vernonia guineensis Benth. (Asteraceae) led to the isolation of a new flavone, vernoguinoflavone and a naturally isolated glycerol ester, eicosanoic acid 2‐hydroxy‐1,3‐propanediyl ester, together with eighteen known secondary metabolites including quercetin, luteolin, vernopicrin, vernomelitensin, β ‐amyrin, oleanolic acid, ursolic acid, lupeol, betulinic acid, β ‐carotene, a mixture of stigmasterol and β ‐sitosterol, β ‐sitosterol‐3‐ O ‐ β ‐D‐glucoside, 2,3‐dihydroxypropyl heptacosanoate, pentacosanoic acid, docosan‐1‐ol, tritriacontan‐1‐ol, and heptatriacontan‐1‐ol. Eleven compounds are reported herein for the first time from this species. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, particularly 1D and 2D NMR, and HR‐ESI‐MS and by comparison of their data with those reported in the literature. The crude extract, fractions and some isolated compounds were evaluated for their antibacterial activity against Gram‐negative bacteria: Escherichia coli (ATCC 25922), Shigella flexineri (NR 518), Salmonella muenchen , Salmonella typhimurium and Salmonella typhi (ATCC 19430). All the tested compounds demonstrated inhibitory activities against the tested enteric bacteria with MIC values ranging from 3.12 to 100 μg/ml. Three flavonoids isolated from the most active fraction demonstrated the best bioactivities against Escherichia coli , Salmonella muenchen and Salmonella typhimurium with MIC values ranging from 3.12 to 25 μg/mL.