Postharvest antifungal activity of extracts and compounds from Cinnamomum zeylanicum, Boesenbergia pandurata and Syzygium aromaticum against Colletotrichum gloeosporioides and Botryodiplodia theobromae.
Khewkhom N., Shangchote S.
Author Affiliation: Department of Plant Pathology, Kasetsart University, Bangkok 10900, Thailand.
Asian Journal of Food and Agro-Industry 2 : S125-S132
Abstract : The objective of this study was to investigate the efficacy of three crude extracts on the infection of two important postharvest pathogens of mango fruit. The in vitro the activity of eugenol oil against Colletotrichum gloeosporioides and Botryodiplodia theobromae and also the possibility of integrating crude extracts to reduce postharvest decay of mango was investigated. Lipophilic extracts of three spices; Cinnamomum zeylanicum, Boesenbergia pandurata and Syzygium aromaticum were selected for investigation of their antifungal properties. Antifungal compounds against Cladosporium cladosporioides were detected using silica TLC plates in bioautography. Comparative studies of all the extracts showed clear inhibition zones on TLC plates against C. cladosporioides. In a micro dilution bioassay, the trunk bark extract of C. zeylanicum showed the highest fungicidal activity with a minimum inhibitory concentrations (MIC) value at 1.2 µg/mL against C. gloeosporioides and B. theobromae at 24 48 and 120 hr after infection. In addition a separated fraction on TLC revealed clear differences for the antifungal activity in the bioautography bioassays. The spore germination of C. gloeosporioides was also inhibited with MIC values of 100 µg/mL at 24 hr. However the three crude spice extracts (5,000 and 10,000 ppm) were not able to control anthracnose on 'Nam Dok Mai' mango. In addition, the application of the extracts resulted in the development of skin disorder on the surface of fruits.