Effects of Aqueous and Ethanol Extracts of Cassia alata on Yam Rot

Abstract

The objective of this study is to isolate, identify and to determine the effect of various concentrations of aqueous and ethanol extracts from the leaves of the test plant Cassia alata in the control of fungal isolates from yam rots in Wukari Nigeria. Rotted yam tubers were obtained from three markets in Wukari. The ingredients of test plant were extracted by aqueous and ethanol solvents. Leaf extracts of different concentrations (0 %, 20 %, 40 % and 60 %) of aqueous and ethanol extraction of the test plant was poisoned to growth media prior to inoculation. The fungi associated with the spoilage of the sample of the yam tuber were identified base on their morphological characteristics. Of all the samples studied, three species of fungi were found to be associated with the yam rots. The most commonly isolated fungi were Aspergillus niger and others are Aspergillus flavus and Rhizopus stolonifer. All concentrations used suppressed the mycelia growth of the tested pathogens. The effect was proportional to concentration and inhibition value was lowest at 60 % concentration, For aqueous and ethanol extractions, Cassia alata was more effective on Aspergillus niger, Phytochemical analysis showed that the presence of alkaloids, flavoniods, tannin,s saponins, phenols, glycosides, terpenoids, anthracenes and steroids in the leaves of Cassia alata, might have conferred the anti-fungal properties on these fungi species. Application of the fungal pathogens on the fungal pathogens isolated on healthy tubers and the subsequent development of rots confirmed these organisms as the natural pathogens of this crop. The extracts from both aqueous and ethanol exerted significant anti-fungal effect on all the test organisms at 60 % concentration, and this concentration would help to minimize infection and spoilage during and after storage and improve farmer’ revenue.

Keywords: Yam rot, leaf extracts, Acasia alata, pathogenicity, phytochemical