INVESTIGATION OF ANTICANCER PROPERTY OF METHANOLIC LEAF EXTRACT OF SPONGE GOURD (Luffa cylindrica Roem)

Abstract

Luffa cylindrica (L.) M.Roem, has been used in traditional medicine for the treatment and management of various diseases like inflammatory diseases, viral infections and cancer. This study investigated the in vitro and in vivo anticancer properties of sponge gourd (Luffa cylindrica) methanol leaf extract. The extract was prepared by maceration. Phytochemical constituents’ evaluation using, high performance liquid chromatography, gas chromatography coupled mass spectrometry analyses and in vitro antioxidant ability of LCE were assessed. The toxicological investigation of the extract was conducted to determine its safety and establish the doses for in vivo experiment. The cytotoxicity activity of the extract was evaluated in two different colorectal cancer cell lines using MTT assay. In vivo anticancer activity of the extract was assessed in Wistar rats. Colon tumor was induced in Wistar rats with 1, 2 dimethylhydrazine (DMH) (20 mg/kg s. c.) twice in a week for 8 weeks and cotreated with extract (100 and 200 mg/kg), standard antineoplastic drug 5-Fluorouracil (3 mg/kg) for 8 consecutive weeks. The effect of the extract on biochemical parameters and molecular markers of colon carcinogenesis were determined. At sacrifice, animals were grossly examined for tumor incidence, microscopically for aberrant crypt foci and histopathological evaluation of colon tissues was also carried out. Molecular Docking analysis was equally carried. Results showed that the total phenols, total flavonoid, total saponin and the total antioxidant capacity of LCE was 24.02± 0.92 mg GAE/g, 20.02 ± 0.70 mg QE/g, 75.81± 1.09mg SE/g and 50.47± 0.57 mg GAE/g extract respectively. The GC-MS analysis revealed the presence volatile phytoconstituents including alcohols, terpenes, phenols, fatty acids and steroids while HPLC analysis identified 12 distinct compounds with p- coumaric acid, diosmetin, luteolin, sapogenin sapogenin 2 and aegyptinin A as the predominant bioactive compounds. The extract has high antioxidant and free radical scavenging activity as evidenced by the low IC50 values: DPPH* (19.59±0.30), ABTS* (8.632±0.47), FRAP (34.05±0.33), NO (22.52±0.32) and OH (20.03±0.33) respectively, compared with their respective reference standard values. The cytotoxicity assay showed a dose dependent increase in activity on HT-29 and HCT 116 cell lines with higher activity on HCT116 cells. The LD50 of the extract was greater than 500 mg/kg. Extract treatment decreased tumor incidence, reduced the number of ACF and restored the altered antioxidant status. Extract treatment significantly inhibited the pro-inflammatory cytokine production, anti-apoptotic Bcl-2 gene, and induces apoptosis in DMH-induced colon cancer model. LCE significantly downregulated β-catenin, cyclin D1, upregulated tumor suppressor P53; genes involving in cell proliferation, differentiation, and apoptosis. Docking analysis showed that 1-caffeoyl-beta-D-glucose has the highest binding energy (-11.516 Kcal/ mol) among the identified phytochemicals and a potent inhibitor of COX-2. This study validated the medicinal potential of LCE as a promising anti- colorectal cancer agent potent against both human colon cancer cell lines HT-29 and HCT 116 and DMH induced colon cancer in Wistar rats.