Cytotoxicity, genotoxicity, and gene expression changes induced by methanolic extract of Moringa stenopetala leaf...

Moringa stenopetala (Baker f.) Cuf.and other Moringa species have traditionally been used to treat various diseases. The purpose of this study was to determine the cytotoxic and genotoxic effects of the methanolic extract of M. stenopetala leaf and its fractions on selected tumor cells. Cytotoxicity was determined by MTT assay. The comet assay was used toassess DNA damage, and gel electrophoresis was used to determine DNA fragmentation. Gene expression was analyzed by qPCR using two specific genes for each cancer cell line. Fractionation of the methanolic extract (E-1) on Diaion HP-20 yielded five fractions (Fr-2 to Fr-6); only Fr-4 and Fr-6 were cytotoxic to breast cancer cells (MCF-7; IC₅₀ = 58.3 ± 0.93 and 35.8 ± 2.44 μg/mL, respectively), human hepatocellular carcinoma cells (HepG2; IC₅₀ = 57.8 ± 1.57 and 39.3 ± 1.90 μg/mL, respectively), and Fr-4 was cytotoxic to human colon cancer cells (HCT-116; IC₅₀ = 94.2 ± 4.9 μg/mL). In addition, exposure of the cancer cells to Fr-4 and Fr-6 resulted in a high level of DNA damage. Moreover, relative expression of MTAP and CDKN2A in MCF-7 were increased, whereas expression of p21 and p53 in HCT-116, and APC and TERT in HepG2 were decreased, similar to that of doxorubicin. LC-qTOF-MS was used to identify metabolites in E-1, the majority of which were enriched in Fr-4. Two terpenes (loliolide and dihydroactinidiolide), the majority of the flavonoids, and niazirin were about two fold enriched in Fr-4, whereas the majority of the lipids were 4-10 fold enriched. However, Fr-6 hardly showed compounds other than the two terpenes that were enriched 1.5 and 7 fold. The findings suggest that Fr-4 and Fr-6 are promising sources of compounds possessing cytotoxic and genotoxic properties.