Pentacyclic triterpenes and crude extracts with antimicrobial activity from Cameroonian brown propolis samples.
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Date
2014-07
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Abstract
The aim of this study was to isolate compounds from Cameroonian propolis extracts and to test their activities
against bacteria isolated from carcass at the Yaoundé slaughterhouse. The n-hexane, ethyl acetate and ethanol
extracts of propolis samples from Ngaoundal and Tala-Mokolo were separated by successive silica gel column
chromatography to give six triterpenes. Their structures were determined as 25-cyclopropyl-3β-hydroxyurs-12-
ene (7), cycloart-3β-hydroxy-12, 25(26)-diene (8), lup-20(29)-en-3-one (9), olean-12-en-3β, 28-diol (10), lup-
20(29)-en-3β-oate (13) and 3β-hydroxylup-20(29)-ene (14). Compounds 7 and 8 were new triterpene derivatives
while 10 and 13 were isolated for the first time from propolis. The structures of all the compounds were
established on the basis of spectroscopic analysis. Phytochemical screening of the methanol extract (5) revealed
the presence of alkaloids, reducing compounds, coumarins, saponins and tannins accounting for its broad
spectrum antibacterial activities. The six isolated compounds and crude extracts were tested for antimicrobial
activity against some Gram negative bacteria. The methanol extract (5) of propolis samples was active against
Escherichia coli and Pseudomonas aeruginosa (MIC: 0.2 mg/ml) whereas the isolated compounds 7, 8 and 10
exclusively exhibited antimicrobial activity against Salmonellas pp (MIC: 0.1-0.15 mg/ml). The MIC values of
all the four propolis products were greater than that of the standard drug (Amoxicillin): 0.1-0.2 mg/ml versus 0.4
mg/ml. Nevertheless, further pharmacological and toxicity studies on experimental animals are necessary to
establish the safety of the propolis products for its use as topical antimicrobial agents.
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Keywords
Cameroonian propolis, crude extracts, isolation, triterpenes, phytochemical screening, antimicrobial activity
Citation
Paul Sakava, Emmanuel Talla, Matchawe Chelea, Alembert Tchinda Tiabou, Elisabeth Zeuko’o Menkem, Sophie Laurent, Luce Vander Elst, Maurice Tagatsing Fotsing, Joel Yaya Gbaweng Abel, Atchade De Théodore Alex Joseph Mbafor Tanyi. Pentacyclic triterpenes and crude extracts with antimicrobial activity from Cameroonian brown propolis samples. Journal of Applied Pharmaceutical Science. 2014 July; 4(7): 1-9.