Abstract

Vernonia amygdalina, Del (Compositae) is an African medicinal plant well known for producing the anticancer agents’ vernodaline and vernolide. It grows wild under severe anthropogenic and environmental pressures. The roots are the principle material for herbal medicine. It is collected from the wild there is great variability in the quality and effectiveness of the root extracts. It is necessary to establish a fast-growing root culture and to test the extracts of cultured roots for activity against leukemia cells in vitro. Leaves were cultured on half-strength MS medium supplemented with different auxin types and concentrations. Basal medium supplemented with indole-3-butyric acid (IBA) at 2.0 mg/l favored induction of the highest number of roots/explant (38.3 ± 1.1). After six weeks well-established roots were separated. About 100 mg of fresh root tissue was cultured in 80 ml full-strength MS liquid medium supplemented with 2.0 mg/l IBA and under continuous agitation (80 rpm). The biomass of root cultures increases by 21 fold after 5 weeks of culture. Cold water, hot water and ethanol extracts from the in vitro cultured roots were prepared and tested for their antioxidant activity and efficacy against leukemia cells. All of the extracts showed significant antioxidant activity. All the extracts could kill the majority (50-75%) of abnormal cells among primary cells harvested from 3 patients with acute lymphoblastic leukemia (ALL) and 3 with acute myeloid leukemia (AML). DNA fragmentation patterns were detected within treated cells and inferred targeted cell death by apoptosis. The metabolites within the extracts may act as tumor inhibitors that promote apoptosis. Therefore in vitro root culture can be an alternative to collection from the wild, cultivation in the field or to chemical synthesis of anticancer agents. In addition the plant extracts may be used to supplement or replace established drugs treatments.

Key words: Anticancer, natural products, plant extracts