BACKGROUND : Medicinal plants are used by many ethnic groups as a source of medicine for the treatment of various ailments in bothhumans and domestic animals. These plants produce secondary metabolites that have antimicrobial properties, thus screening ofmedicinal plants provide another alternative for producing chemical fungicides that are relatively non-toxic and cost-effective.MATERIALS AND METHODS : Leaf extracts of selected South African plant species (Bucida buceras, Breonadia salicina, Harpephyllumcaffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana) were investigated for activity against selectedphytopathogenic fungi (Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, P.expansum, Trichoderma harzianum and Fusarium oxysporum). These plant fungal pathogens causes major economic losses in fruitindustry such as blue rot on nectaries and postharvest disease in citrus. Plant species were selected from 600 evaluated inter alia,against two animal fungal pathogens (Candida albicans and Cryptococcus neoformans). Antioxidant activity of the selected plantextracts were investigated using a qualitative assay (2, 2-diphenyl-1-picrylhydrazyl (DPPH)). Bioautography assay was used todetermine the number of antifungal compounds in plant extracts.RESULTS : All plant extracts were active against the selected plant phytopathogenic fungi. Moreover, Bucida buceras had the bestantifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum. The plant extracts of five plant species did not possessstrong antioxidant activity. However, methanol extract of X. kraussiana was the most active radical scavenger in the DPPH assayamongst the six medicinal plants screened. No antifungal compounds were observed in some of the plant extracts with goodantifungal activity as shown in the microdilution assay, indicating possible synergism between the separated metabolites.CONCLUSION : The results showed that acetone was the best extractant. Furthermore, our findings also confirm the traditional use ofBreonadia salicina and demonstrate the potential value of developing biopesticides from plants.
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