PROF. OKOTH SHEILA

Citation:

Okoth S. "Effects of Medicinal Plant Extracts and Photosensitization on Aflatoxin Producing Aspergillus flavus (Raper and Fennell)." International journal of microbiology. 2017:1-9.

Abstract:

This study was undertaken with an aim of exploring the effectiveness of medicinal plant extracts in the control of aflatoxin
production. Antifungal properties, photosensitization, and phytochemical composition of aqueous and organic extracts of fruits
fromSolanumaculeastrum, bark fromSyzygium cordatum, and leaves from Prunus africana, Ocimum lamiifolium, Lippia kituiensis,
and Spinacia oleracea were tested. Spores from four-day-old cultures of previously identified toxigenic fungi, UONV017 and
UONV003, were used. Disc diffusion and broth dilution methods were used to test the antifungal activity. The spores were
suspended in 2ml of each extract separately and treated with visible light (420 nm) for varying periods. Organic extracts displayed
species and concentration dependent antifungal activity. Solanum aculeastrum had the highest zones of inhibition diameters in
both strains: UONV017 (mean = 18.50 ± 0.71 mm) and UONV003 (mean = 11.92 ± 0.94 mm) at 600mg/ml. Aqueous extracts
had no antifungal activity because all diameters were below 8 mm. Solanum aculeastrum had the lowest minimum inhibitory
concentration at 25mg/ml against A. flavusUONV017.All the plant extracts in combinationwith light reduced the viability of fungal
conidia compared with the controls without light, without extracts, and without both extracts and light. Six bioactive compounds
were analyzed in the plant extracts. Medicinal plant extracts in this study can control conidia viability and hence with further
development can control toxigenic fungal spread.

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