Cymbopogon citratus (CC) and Citrus medica (CM) are plants consumed in Cameroon in the form of herbal tea for the prevention and treatment of various conditions including cancers. To provide scientific proof of the suggested anticancer effect of these plants, the genotoxic and anticancer effects of the aqueous extracts of these plants were studied respectively on the germ cells of locusts (Zonocerus variegatus) and on the breast cancer in rats. The germ cells of locusts were exposed to increasing concentrations (0.25; 0.5 and 1 mg/mL) of CC and CM for 72 hours. They were then examined microscopically to evaluate the meiotic index and aberration index. Breast cancer was induced by a single oral administration of 7,12-dimethyl[a]anthracene (DMBA; 50 mg/kg BW). Plant extracts were administrated orally, 7 days before cancer induction and throughout the observation period (196 days). Animals were then sacrificed for biochemical analyses. The anticancer effects were evaluated on the serum levels of steroid hormones, immune markers and pro-inflammatory cytokines. Results showed that CC and CM inhibited Z. variegatus germ cell division by inducing chromosomal abnormalities (p< 0.001). In rats, CC and CM reduced tumor burden and incidence through a mechanism of action involving activation of the cytotoxic immune response illustrated by elevated levels of granulocytes, lymphocytes, monocytes and pro-inflammatory cytokines. Overall, using the two plants together was more effective than using them separately. These results justify the empirical use of CC and CM against cancers and suggest that both plants could be useful dietary supplements for cancer patients.

Keywords: Zonocerus variegatus; Citrus medica; Cymbopogon citratus; Genotoxicity; Breast cancer; Rats