ABSTRACT
The extraction of natural antifungal compounds from the peels of yam (Dioscorea alata) and the effect of these compounds on both the vegetative and reproductive structures of some yam not pathogens were studied. Four prominent antifungal components were obtained; one of the components was fully characterized and identified as beta-sitosterol. The antifungal activity of the compounds toward the germination of spores of two yam pathogens showed an inhibition of less than 57% at a concentration of 50 mg/L while inhibition on the elongation of germ-tubes of Fusarium moniliforme was as high as 82% at the same concentration. However, the ED50 for inhibition of germ-tube elongation in the yam compounds for the same organism was below 32 mg/L. The role of the yam compounds at high concentrations in disease resistance is discussed.
Subject(s)
Antifungal Agents/isolation & purification , Vegetables/chemistry , Vegetables/microbiology , Antifungal Agents/pharmacology , Cladosporium/drug effects , Fusarium/drug effects , Penicillium/drug effects , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Spores, Fungal/drug effectsABSTRACT
The effect of beta-sitosterol on spore germination and prevention of elongation of germ-tube of Aspergillus niger and Botryodiplodia theobromae was studied. The antifungal activity of the compound showed a percentage inhibition, of the fungal spore germination, of about 40% at a concentration of 50 micrograms/ml while inhibition on the elongation of germ-tubes was as high as 65% at the same concentration. The ED50 for inhibition of germ-tube elongation in A. niger was about 31 micrograms/ml. The role of the compound in disease resistance is discussed.
Subject(s)
Aspergillus niger/drug effects , Food Microbiology , Mitosporic Fungi/drug effects , Sitosterols/pharmacology , Aspergillus niger/growth & development , Aspergillus niger/physiology , Mitosporic Fungi/growth & development , Mitosporic Fungi/physiology , Plant Diseases , Spores, Fungal/drug effectsABSTRACT
A species of Aspergillus was isolated from vomitus and scrapings of the tongue of a patient with a form of respiratory illness. The fungus has since been identified as Aspergillus aculeatus, Iizuka. The fungus grew over a wide range of temperatures, the spores appeared to be thermophilic. Many local foodstuffs supported the growth of the fungus in culture. Ultraviolet light inhibited mycelia growth and sporulation of A. aculeatus. The fungicides brestan, benlate, fundazole and kocide 101 inhibited the growth of the fungus more than daconil, demosen and dithane M-45. Amphotericin B and sulfadiazine completely arrested the growth of the fungus while sulfamycin, nalidixic acid and kanamycin had no detectable effects.