Betulin caffeate

Secondary metabolites (Triterpenes) from Couroupita guianensi[Reference: WebLink]

Oriental Pharmacy and Experimental Medicine, 2009 9(2), 200-205.

METHODS AND RESULTS:
The n-hexane and carbon tetrachloride soluble fractions of a methanolic extract of the stem bark of the Couroupita guianensis furnished three compounds, identified as β-amyrin (1), betulin-3β- caffeate (Betulin caffeate,2) and lupeol-3β-caffeate (3). The structures of the isolated compounds were deduced by extensive spectroscopic analysis as well as by comparison with published values.
CONCLUSIONS:
Compounds 1-3 were subjected to antioxidant screening through free radical scavenging activity by DPPH (1,1- diphenyl-2-picrylhydrazyl), where compound 2 showed moderate antioxidant activity with IC50 value 108.0 μg/ml

Chemistry of Natural Compounds, 1987 , 23 (4) :513-514.

Isoprenoids of the outer bark of the Far Eastern birches Betula costata and Betula ermanii[Reference: WebLink]

METHODS AND RESULTS:
(4), the acetate of oleanolic acid (III), lupeol (IV), methyl oleanolate (V), betulin (VI), bet- ulinic acid (VII), oleanolic (VIII), and Betulin caffeate (IX). Compounds (VI-IX) were iso- lated after the acetylation of the fraction containing a difficultly separable mixture of these components. Extracts of the bark of B. costata and B. ermanii (samples 2 and 5) showed antioxidant activity according to the method of Maximov et al. (5).
CONCLUSIONS:
The activity of these samples is obviously connected with the presence of Betulin caffeate (6), since this component was pres- ent only in summer samples of the bark. The results of the investigation are given in Table i. The structures of the compounds isolated were confirmed by mixed melting points with authen- tic samples (no depression of the melting points was observed) and by comparison of their !R spectra.