Phytochemical, Antioxidant and Antimicrobial Activity of Ethanol and Aqueous Stem Extracts of Pseudocedrela kotschyi
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Pharmaceutical Journal of Kenya
Abstract
Introduction: Secondary plant metabolites found in
medicinal plants have been known to have antimicrobial
activity against a wide range of microorganisms including
orodental, respiratory and urinary pathogens.
Aim: The aim of this research was to evaluate the
phytochemical, antioxidant and antimicrobial activity of
aqueous and ethanol stem extracts of Pseudocedrela kotschyi
(Pk), a plant of use in folklore medicine, against dental and
other community acquired infections caused by pathogens,
so as to validate some of its therapeutic claims.
Methodology: The plant metabolites were extracted (cold
maceration method) using distilled water and 70 % ethanol
for aqueous and ethanol extract respectively. Preliminary
phytochemical screening was carried out on the extracts to
determine various secondary metabolites. Total flavonoid
and phenolic contents were determined using
Folin-Ciocalteu’s reagent and colorimetric aluminium
chloride method respectively. The antimicrobial activity was
investigated using agar well diffusion method. The
antioxidant activity was assayed using 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,20-azinobis-(3-ethylbenzothiazoline-
6-sulphonate) (ABTS+) and ferric reducing antioxidant
power (FRAP).
Results: Both the aqueous and ethanol extract were found
to contain alkaloids, flavonoids, saponin, cardiac glycosides,
steroids, terpenoids, carbohydrates, phenols and tannins.
The flavonoid and phenolic contents in both aqueous and
ethanol stem extracts of Pk was found to be 0.099 ± 0.01 and
0.399±0.0 mg/mL quercetin equivalent and 0.48±0.00 and
1.38±0.01mg/g gallic acid equivalent respectively. The zones
of inhibition were found to be from 3-20mm and 4-18mm
for the ethanol and aqueous extracts respectively. The
standards cultures were highly susceptible to the two
extracts while the clinical isolates were mostly resistant. The
DPPH and percentage ABTS•+ scavenging activity was found
to be highest at 0.0312 and 0.0625 mg/mL, 0.5 and 0.25 mg/
mL for the aqueous and ethanol extract respectively. The
percentage FRAP activity was highest at 0.50 mg/mL for
both extracts.
Conclusion: This research confirms the presence of
phytochemicals responsible for antioxidant and
antimicrobial activity against orodental, respiratory and
urinary pathogens. It was found that ethanol extract of Pk
inhibited 80% of the pure isolates of bacterial strains under
investigation while the aqueous extract inhibited less than
70% of the same organisms.
Description
Keywords
Pseudocedrela kotschyi, antimicrobial, antioxidant, chewing stick, ethanol and aqueous extract