Effects of Flavonoid Fractions from Calendula officinalis Flowers in Parent and Tamoxifen Resistant T47D Human Breast Cancer Cells

Three major flavonoid fractions were separated from a methanol extract ofcalendula officinalis flowers by preparative tlc. these fractions were evaluatedfor the inhibition of parent and tamoxifen resistant t47d human breast cancercells. we also examined the effect of quercetin and isorhamnetin on the growth ofparent and resistant t47d cells in the presence and absence of tamoxifen. it was foundthat quercetin increased cell proliferation of the resistant t47d cells at the presenceof tamoxifen but no effect was detected by using quercitin alone. the fractions isolatedfrom calendula officinalis did not show any inhibitory effects on the cells.isorhamnetin did not have any proliferative or anti-proliferative activity on the bothcell lines.