Holy basil (Ocimum sanctum), a member of the mint family, has long been one of the most popular herbs used in European and Asian countries for the treatment of various ailments. The authors previously reported that aqueous extracts of holy basil leaves inhibited chemotaxis of breast cancer cell lines MDA-MB-435 and MDA-MB-231, and endothelial cell line HUVEC towards specific chemo attractants. Two human breast cancer cell lines were used to explore if holy basil extracts have an inhibitory effect on breast cancer; namely MDA-MB-435 and MCF10A DCIS.com (DCIS.com) cells. Injection of DCIS.com cells into nude mice results in lesions that are mainly DCIS subtype. When holy basil extract was fed to mice injected with MDA-MB-435 or DCIS.com cells, there was a significant decline in the rate of tumor growth in the treated mice. Initially, the tumors in holy basil-fed mice grew at comparable rates as the water fed controls, although their overall size was smaller than that of the controls. After reaching a tumor size of approximately 150mm3 in DCIS.com or 200 mm3 in MDA-MB-435, the growth rate started to attenuate. This inhibition in tumor growth was found to be a result of reduced cell proliferation and angiogenesis. There was also a reduced expression of COX-2, MMP-9 and redistribution of VEGF in the holy basil-treated xenografts. The authors conclude that holy basil extract inhibits breast cancer growth and progression by affecting cell proliferation and angiogenesis.

Crude aqueous extracts were prepared from the leaves of holy basil and performed in vitro and in vivo studies. The extracts were shown to significantly inhibit breast cancer cell (MDA-MB-435) migration. Holy basil extract also inhibited the induction of cycloxygenase COX-2 in MDA-MB-231 breast cancer cells treated with tetradecanoyl phorbol acetate. The authors conclude that holy basil leaf extract can be used as an anti-tumorigenic and anti-angiogenic agent in breast cancer models.