Cytotoxic Plumbagin-5-O-α-l-Rhamnopyranoside from Plumbago indica

The chemical investigation of Plumbago indica L., Plumbaginaceae, has led to isolation and identification of one new naphthoquinone glycoside identified as plumbagin-5-O-α-l-rhamnopyranoside and seven known compounds identified as plumbagin, stigmasterol, β-sitosterol, quercetin-3-O-α-l-rhamnopyranoside, quercetin-3-O-β-d-glucopyranoside, quercetin, and kaempferol. Their structures were determined by chemical and spectral analysis. Plumbagin-5-O-α-l-rhamnopyranoside was evaluated for its cytotoxic activities against various human cancer cell lines using the sulforhodamine B assay. The results showed that the new glycoside exhibited variable inhibitory activities for all tested cancer cell lines, especially against hepatocellular carcinoma (HepG-2) and breast cancer (MCF-7) cell lines with IC50 values equal to 7.93 ± 0.15 μM and 9.03 ± 0.5 μM, respectively.