Synthesis of (+/-)Abyssinone I and related compounds: Their anti-oxidant and cytotoxic activities.

An efficient and facile synthesis of naturally occurring prenylated flavonoids and their analogs have been described. Abyssinone I (9a) was prepared by condensing 2,2-dimethyl chrom-3-en-6-carboxaldehyde (5a) with protected resacetophenone under phase transfer conditions followed by deprotection and cyclization. The influence of prenyl group on anti-oxidant and cytotoxic activities was studied. The presence of 3'-prenyl group as in 8c enhanced radical scavenging activity but decreased reducing power activity when compared to non-prenylated analog 8f. In vitro testing in MCF-7 cell line revealed that prenylated chalcones and flavanones showed better inhibitory activity than their non-prenylated counterparts. Abyssinone I and its chalcone though exhibited negligible anti-oxidant activity their cytotoxic activities were comparable with other prenylated analogs.