Antibacterial and antioxidant properties of crude extract, fractions and compounds from the stem bark of Polyscias fulva Hiern (Araliaceae)

Abstract

BackgroundIn our previous work, the dichloromethane-methanol (1:1 v/v) extract, fractions and isolated compounds from Polyscias fulva stem bark showed interesting antifungal activity. As a continuity of that work, this study aimed to bring out complementary informations about the antimicrobial properties of P. fulva stem bark that may be useful in the standardization of phytomedicine from this plant.MethodsThe antibacterial activities of the crude extract, fractions (n-hexane, ethyl acetate, n-butanol and residual) and isolated compounds from Polyscias fulva stem bark were assayed by broth microdilution techniques. Their antioxidant activity were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), pyrogallol (superoxide anion) and β-carotene - linoleic acid assays.ResultsThe crude extract presented antibacterial activities against S. typhi (ATCC 6539), E. aerogenes (ATCC 13045), P. aeruginosa (PA01) and E. coli (ATCC 10536) with MIC values of 2000 to 8000 μg/ml. The fractionation led the ethyle acetate and n-butanol fractions relatively more active (MIC = 500 to 1000 μg/ml) as compared to the crude extract. β-sitosterol and 3-O-α-L- arabinopyranosyl-hederagenin were the most active compounds on the tested bacteria with MIC values ranging from 6.25 to 100 μg/ml. The most sensitive was P. aeruginosa (PA01) on which all the tested compounds were active with MICs ranging from 6.25 to 400 μg/ml. Among all the tested substances, the crude extract (RSa50 = 84.86 μg/ml) and the methyl atrarate (RSa50 = 14.77 μg/ml), showed the highest scavenging activities against DPPH free radicals and those arising from the oxidation of the linoleic acid respectively.ConclusionFrom this study, the results obtained reveal that the stem bark of P. fulva possesses antibacterial and antioxidant activities. It may then be useful in the development of an antimicrobial phytomedicine with a large spectrum of actvity endowed with antioxidant properties which can be standardised based on the isolated compounds.

Antibacterial Activity Against Bacillus Subtilis and Antioxidant Properties of Methanol Extracts From Garcinia Latissima Miq. Leaves

“…Bacterial cell suspensions were prepared separately from 24-h Mueller-Hinton agar cultures. Colonies of microorganisms were diluted in 0.9% NaCl to obtain a McFarland standard turbidity of 0.5 using visual assessments and then diluted to approximately 10 6 CFU/ml [1].…”

“…To determine MIC values of test substances, broth microdilution assays were performed in 96-well microplates [1]. Assays in 96-well microplates were prepared by adding 50-μL aliquots of test substances to the first wells and three-fold serial dilutions in subsequent wells.…”

“…Radical scavenging activities of extracts and compounds were determined using the stable free radical, DPPH [1]. Test substances from fractions were added at 100 μg/mL and dissolved with DPPH (150 mM) in methanol [10,11].…”

“…The present fractionation process separated extracts into 14 fractions (A-N) with fewer active ingredients than the parent extract, and fractions B and C had greater activity when compared with the other fractions. In the most active fractions, the fractionation process likely reduced the antagonistic effects of contaminating compounds [1].…”

“…The relationship between antibacterial activity and contents of active compounds in plant extracts or fractions of G. latissima have been investigated in multiple previous studies [1,[17][18][19][20][21]. Moreover, phytochemical tests of methanol extracts of G. latissima leaves showed the presence of tannin and saponin, which are known phytochemicals with health benefits and biological activities [4].…”