ANTIBIOFILM EFFECTS OF PARTIALLY PURIFIED FRACTION OF ETHYLACETATE EXTRACT OF ACALYPHA WILKESIANA LEAVES ON CLINICAL ISOLATES OF CANDIDA ALBICANS I, II AND CANDIDA PARAPSILOSIS
ANTIBIOFILM EFFECTS OF PARTIALLY PURIFIED FRACTION OF ETHYLACETATE EXTRACT OF ACALYPHA WILKESIANA LEAVES ON CLINICAL ISOLATES OF CANDIDA ALBICANS I, II AND CANDIDA PARAPSILOSIS
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Date
2021
Authors
MAIMUNA ZUBAIRU,
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Abstract
Candida infection is the most common hospital-acquired infection caused by
fungal pathogen which is frequently involved in biofilm growth, exhibiting to
increased resistance to antifungal drugs. This research is aimed at evaluating the
biofilm eradication activity of purified fraction of ethylacetate extract of Acalypha
wilkesiana leaves on biofilms of C. albicans I, II and C. parapsilosis. Column
Chromatography-TLC was used to fractionate and partially purify the extract
using a bioassay guided fractionation. The most potent fraction was partially
purified using preparative TLC. The minimum inhibitory concentration (MIC) ,
and median inhibitory concentration (IC50) were carried out using micro dilution
method. Fungicidal activity (MFC) of the purified fraction was determined by
agar well diffusion method. Adhered cells penetrability of the extracts was carried
out by forming adhered cells on membrane polycarbonate filters, and determining
the concentration of the antifungals that penetrated the adhered cells with time.
Median adhered cells (AdEC50) and median biofilm eradication concentration
(BEC50) were determined by microdilution method. Antibiofilm activity of the
purified fraction on the morphology of the sessile cells of Candida spp was
evaluated by scanning electron microscopy. The mode of action was predicted by
the use of sorbitol and ergosterol to evaluate their effect on the IC50 of the
antifungal and comparing it with the IC50 of caspofungin and Amphotericin B
which are standard antifungals with known mode of actions. The result revealed
that ethylacetate extract was the most potent with antifungal activities compared
to n-hexane, methanol and aqueous extracts of A. wilkesiana leaves. The purified
fraction of the ethylacetate extract had MIC of 1.25mg/ml on C. albicans I, II and
C. parapsilosis, respectively. MFC of 2.5mg/ml on C. albicans I and II but had
no fungicidal activity on C. parapsilosis. The partially purified fraction had
minimum values of IC50 and BEC50 compared to other fractions. There was
reduction in clusters formed by proliferation of the sessile cells on the
morphology of C. albicans I, II and C. parapsilosis in all treated plates compared
to the control. There was increase in the IC50 of the purified fraction and
caspofungin in the presence of sorbitol. In conclusion, the partially purified
fraction of ethylacetate extract had antibiofilm activity against the three strains of
Candida used. Increased in IC50 of the purified fraction and caspofungin
implicated the fungal cell wall as the possible target of the partially purified
fraction of ethylacetate extract of A. wilkesiana leaves
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE AWARD OF A DOCTORATE DEGREE IN
BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY, FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA