Fungicidal Property of Andrographis paniculata extract on Fungal Organisms from Citrullus colocynthis (L.) Schrad (Melon Seeds)

Abstract

Antifungal property of A. paniculata on fungal isolates from Citrullus colocynthis was investigated. Citrullus colocynthis were bought from traders in a major market in Abia State, Nigeria. The melon seeds were first cleaned and disinfested by keeping them in a freezer at -50C for 7 days to kill all hidden infestations. The disinfested seeds were dried in a Gallenkamp oven at 40oC for 4 hours before they were stored in plastic sterile containers with tight lids. Fresh plant of A. paniculata was collected from botanical garden of the Rivers State University and was identified in the botany department. The leaves of the plant were shade dried and blended into fine powder. Twenty grams (20g) of the powdered leaves was extracted using methanol and ethanol. The filtrate was evaporated and the resulting crude extract was used for antifungal sensitivity test. Fungi associated with rotted C. colocynthis were identified using standard microbiological methods. The antifungal activity of the extracts was carried out using the well in agar diffusion method. In this method, 48 hours old fungal isolate was inoculated on dried Sabouraud Dextrose Agar plates in duplicates. five wells were bored using sterile 6mm cork borer on the dried seeded plates before 0.2ml of the different concentrations of 100, 50, 25, and 12.5mg/ml of the methanol extracts were transferred into the wells using sterile pipettes. Aspergillus flavus, Rhizopus arrhizus, Aspergillus niger, Rhizopus sp and Mucor sp were identified from the melon seeds. The zone diameters of methanolic extract of A. paniculata on Rhizopus arrhizus, A. niger, A. flavus, Rhizopus sp and Mucor sp were 11.50±0.71, 19.50±0.71, 34.50±0.71, 15.00±0.00 and 17.00±0.00mm, respectively. The zone diameters of ethanolic extract of A. paniculata on Rhizopus arrhizus, A. niger, A. flavus, Rhizopus sp and Mucor sp were 0.00±0.00, 16.50±0.71, 34.50±0.71, 20.50±0.71 and 0.00±0.00mm, respectively. There were significant differences (P ≤ 0.05) in the antifungal activity of the extract across the fungal isolates. The antifungal activity of the leave extracts showed that the ethanolic extract and the methanolic extract were very active on the fungal isolates and the antifungal activities of the extract was greatly influenced by the concentration of the extract, with higher concentrations of extract having high zone diameter.