Antioxidant and antimutagenic effects of the crude foliar extract and the alkaloid brachycerine of Psychotria brachyceras.

The monoterpene indole alkaloid brachycerine from Psychotria brachyceras has been shown to be induced by UV and to have in vitro antioxidant activity, indicating a possible protective role against the secondary effects of this radiation. In this work, we have studied the antioxidant properties of brachycerine and a crude foliar extract from P. brachyceras by using Saccharomyces cerevisiae strains proficient and deficient in antioxidant defenses. The mutagenic and antimutagenic potential of these substances were assayed in S.cerevisiae N123 strain in the presence and absence of H2O2. In addition, we tested the antioxidant capacity of brachycerine and a crude foliar extract from P. brachyceras on hydroxyl radicals (OH) using the hypoxanthine/xanthine oxidase assay. The results show that brachycerine and the crude foliar extract of P. brachyceras have antioxidant and antimutagenic effects in yeast and probably this action is mainly due to the scavenging of OH radicals. (Copyright) 2007 Wiley-Liss, Inc.