| Autor: |
Iqbal, M. C. M., Jayasinghe, U. L. B., Herath, H. M. T. B., Wijesekara, K. B., Fujimoto, Y. |
| Zdroj: |
Phytoparasitica; April 2004, Vol. 32 Issue: 2 p119-126, 8p |
| Abstrakt: |
Ageratum conyzoidesL. is an annual herb in the tropics and subtropics whose extracts are known to possess pharmacological and biocidal activity. We report on the bioactivity of a secondary metabolite (a chromene) isolated from the shoots ofA. conyzoidesagainst some plant pathogenic fungi. Organic solvent extracts from the shoots were tested for antifungal activity against the plant pathogenic fungiRhizoctonia solani, Sclerotium rolfsii, Botryodiplodia theobromae, Phomopsis theaeandFusariumspecies growingin vitroon potato dextrose agar medium. The cruden-hexane extract completely inhibited the growth ofR. solaniandS. rolfsii. Then-hexane extract was chromatographed over a column of silica gel followed by activity-guided fractionation to give an antifungal principle. Structure elucidation by detailed analysis of1H,13C NMR and mass spectroscopy identified the active compound as precocene II. The growth ofR. solaniandS. rolfsiiwas completely inhibited by precocene II at a concentration of 80–100 ppm. The sclerotia ofR. solaniandS. rolfsiiwere also completely suppressed by 150 ppm of precocene II. Sub-culture of these inhibited fungi onto precocene II-free medium restored growth of the fungus, indicating that precocene II is fungistatic. Crude or refined extracts fromA. conyzoidesoffer the possibility of biocontrol of plant pathogenic fungi. |
| Databáze: |
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