New halogenated constituents from Mangifera zeylanica Hook.f. and their potential anti-cancer effects in breast and ovarian cancer cells.

UNASSIGNED

Mangifera zeylanica Hook.f. (Anacardiaceae) is a plant endemic to Sri Lanka. Its bark has been used in traditional and Ayurvedic medicine for the treatment of various diseases including some cancers.

OBJECTIVE

This study was planned to isolate and identify potentially cytotoxic compounds from the bark of M. zeylanica, which may have contributed to its ethno pharmacological use in the treatment of cancer.

METHODS

The chloroform extract of M. zeylanica bark which is cytotoxic to breast and ovarian cancer cells was fractionated using column chromatography and preparative reversed phase high performance liquid chromatography to isolate four compounds. Structures of the isolated compounds were elucidated by means of (1)H- and (13)C NMR spectroscopy, and mass spectrometric techniques. Cytotoxic potential of the isolated compounds was tested in MDA-MB-231 (triple negative breast cancer), MCF-7 (estrogen receptor positive breast cancer), SKOV-3 (ovarian epithelial cancer) and MCF-10A (normal mammary epithelial) cells by SRB assay. Human cancer drug target real-time PCR array was carried out to analyze regulation of possible cancer drug target genes in compound 2 treated triple negative breast cancer cells. DPPH radical scavenging and caspase 3 and 7 induction in response to isolated compounds were also studied.

RESULTS

Two new halogenated compounds, bromomangiferic acid (1), and chloromangiferamide (2) along with two known compounds quercetin (3), and catechin (4), were isolated from the bark of Mangifera zeylanica for the first time. Interestingly, chloromangiferamide showed cytotoxicity only to triple negative breast cancer cells [IC50:73.19±0.87µM (24h), 56.29±0.86µM (48h)] with no cytotoxicity to other two cancer cell lines or to normal mammary epithelial cells. Quercetin and catechin were cytotoxic to all three cancer cell lines while bromomangiferic acid had no effect. Chloromangiferamide significantly regulated expression of genes associated with apoptosis, drug metabolism, cell cycle, receptor tyrosine kinase signaling, protein kinases, histone deacetylases, growth factors and receptors, topoisomerases, PI-3 kinases and phosphatases in triple negative breast cancer cells.

CONCLUSIONS

Selective cytotoxic activity in triple negative breast cancer cells and regulation of some cancer drug target genes by chloromangiferamide indicate that it can be used to develop a potential chemotherapeutic agent for triple negative breast cancer cells.