Isolation and partial characterization of an inhibitory metabolite from Cladosporium fulvum Cooke against aflatoxigenic fungi
1994
Divina, R.D.
A new fungal metabolite produced by Cladosporium fulvum was isolated, purified and characterized. An active peak, 14.657-14.891 min (Part is 5 ODS-2, 10 x 250 mm; 95 percent MeOH in 1 percent HOAc; 1.5 ml/min; UV220 nm), was collected, concentrated to dryness yielding 6.2 mg/l of the antibiotic. The active compound was soluble in methanol, acetone, n-hexane, chloroform, ethyl acetate and benzene but insoluble in water. The culture both inhibited the growth of Aspergillus parasiticus and A. flavus up to a period of more than 75 days. The purified compound showed a biological activity at 100 ug/disc against the aflatoxigenic fungi and Alternaria kikuchianna after 24-36 hrs. incubation. The ultraviolet spectrum of the active compound had maximum absorption of 261.5 nm inferring the presence of chromophoric group(s). Main absorption bands of the infrared spectrum appeared at wavelengths 3300, 3800-3000 and 165/cm, C-H and C=C stretchings were indicated. The compound has-OH groups but no carbonyl functionality. Integration of the total number of protons using the NMR spectrum suggested 26 hydrogen atoms for the compound. Assuming that it contains 18 carbon and 2 oxygen atoms, the calculated molecular weight is 274.404. Therefore, the compound appeared to have 274 as its molecular weight and C18H26O2 as its tentative molecular formula. The available data did not allow full elucidation of the compound
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