Abstract:
Mangrove plants and their associated micro fauna have been a rich source of bioactive
molecules, but only a limited antimicrobial screening of this chemo-diversity source
has been reported. The unique adaptation of mangroves towards their extreme
environment is largely aided by endophytic fungi. Endophytic fungi are
underexplored group of microorganisms since only a few plants have been studied
with regards to this community. Endophytic fungi live inside the tissues of other
organisms, such as mangrove plants and provide protection to them. In return,
endophytic fungi support their hosts by fighting off pathogens through the production
of antimicrobial compounds. These bioactive compounds are the secondary
metabolites which are often produced as waste- or by-products. In this study, the
leaves, barks and roots of red, black and white mangroves found along the Ayensu
estuary and the Muni lagoon in Winneba were screened for their endophytic fungi in a
malt-glucose culture media containing 3%(w/w) malt extract and 6%(w/w) glucose.
Five fungi from BBMAV, BWMS, LBMS, RBMAV and BBMS were obtained and
cultured in malt-glucose media containing 3%(w/w) malt extract and 6%(w/w)
glucose for 8 weeks for their secondary metabolites. The TLC studies and GC-MS
analysis of the crude extracts from culture media of the fungal isolates reveal that
fungi produced several secondary metabolites. A bioassay on the crude extracts was
carried out using human pathogenic microbes Methicillin resistant Staphylococcus
aureus (NCTC 12493), Staphylococcus aureus (NCTC 12973), E. coli (NCTC
12241), S. mutants (ATCC 700610), P. aeroginosa (ATCC 4853), S. typhi (ATCC
14028), K. pneumonia (NCTC 13440) and Candida albicans (ATCC 90028) and two
fungi that infest cocoa (Phytophthora palmivora and Phytophthora megakarya). The
bioassay results indicated that the crude extracts were active against all the test
organisms. The crude extracts were tested for antioxidant activity using ABTS and
DPPH as scavenging agents. The results indicate that the crude extracts of all the
fungal isolates exhibited high antioxidant activity.
Description:
A thesis in the Department of Chemistry Education Faculty of Science Education, submitted to the School of Graduate Studies in partial fulfillment of the requirements for the award of the degree of Master of Philosophy (Chemistry Education) in the University of Education, Winneba
August, 2022