Research ArticleAntifungal and anti-mycotoxigenic activity of 25 acetone leaf extracts of South African medicinal plants with
potent antioxidant activity were investigated against three phytopathogenic fungal strains. The extracts exhibited
varying degrees of in vitro anti-mycotoxigenic effect against Fusarium verticillioides, Aspergillus flavus and Aspergillus
ochraceous. Markhamia obtusifolia (Baker) Sprague exhibited the lowest minimum inhibitory concentration (MIC)
values as low as 0.08 mg/ml against Aspergillus flavus and Furasium verticilloides at both 24 and 48 hr incubation
period, while Curtisia dentata exhibited similar MIC value against Aspergillus ochraceous. Curtisia dentata further
yielded the highest total activity of 1583 ml/g against Aspergillus ochraceous at 24 and 48 hr incubation period. In
the mycelial growth inhibition (MGI) evaluation, Fusarium verticilloides was more sensitive to plants extracts,
while Kirkia wilmsii exhibited highest MGI of 50.08% against Fusarium verticilloides on the 6th day of incubation.
Five acetone extracts from Acokanthora oppositifolia, Bauhinia galpinii, Combretum caffrum, Ricinus communis and
Solanum aculeastrum exhibited lowest IC50 value of 0.01 mg/ml against (2,2’-azinobis-3-ethylbenzthiazoline-6-
suphonic acid (ABTS). Curtisia dentata and Markhamia obtusifolia extracts were further subjected to gas chromatography
mass-spectrophotometry (GC-MS) analysis. Curtisia dentata revealed the presence of triterpenoid compounds,
β-amyrin (53.30%) and α-amyrin (6.42%), while Markhamia obtusifolia yielded the presence of
neophytadiene (4.38%) and palmitic acid (3.61%) The results suggest that natural products from plants may well
be used as possible substitutes for synthetic fungicides. Given the antifungal and antioxidant potential of the
selected plants, they may have potential as possible leads for the development of biofungicides that may well
prevent oxidation related food spoilage
