Phytochemical Analyses, Antioxidant and Anticancer Activities of Ethanolic Leaf Extracts of Moringa oleifera Lam. Varieties

Abstract

Moringa oleifera Lam. (Moringaceae) is revered as s ‘miracle tree’ due to its remarkable nutritional, medicinal and industrial uses. In our study, a comparative analysis of the nutritional parameters (antioxidant activity, sugar content—TSS, total soluble proteins—TSP and mineral contents), phytochemicals (HPLC analysis of four anticancer compounds), and cytotoxicity of M. oleifera leaf extracts (MLEs) of five selected varieties (conventional, PKM-1, PKM-2, ODC, and Jaffna), was performed. Jaffna variety possessed the highest antioxidant activity (FRAP) followed by other four varieties. The trend observed was: Jaffna (9.47 µg/mL, 18.48 µg/mL, 29.39 µg/mL, and 35.37 µg/mL) > PKM-1 (4.82 µg/mL, 7.63 µg/mL, 22.33 µg/mL, and 27.71 µg/mL) > PKM-2 (2.10 µg/mL, 7.04 µg/mL, 13.18 µg/mL, and 21.78 µg/mL) > ODC (0.17 µg/mL, 2.10 µg/mL, 4.41 µg/mL and 13.94 µg/mL) > Conventional (0.05 µg/mL, 1.08 µg/mL, 2.86 µg/mL, and 5.40 µg/mL), total soluble proteins (TSP) [0.69 ± 0.01 and 0.94 ± 0.01 µg/mL (young and mature stage, respectively)], sugar content (TSS) [0.39 ± 0.01 and 0.51 ± 0.01 µg/mL (young and mature stage, respectively)], chlorophyll content [1.07 ± 0.01 (plantlet stage), 1.36 ± 0.003 (vegetative-stage), 0.82 ± 0.004 (reproductive stage) mg/g], followed by the other four varieties. The trend observed for cytotoxic activities of ethanolic MLEs on HepG2 cell line, based on the IC50 values, was conventional (1.22 mg/mL) > ODC (0.90 mg/mL) > PKM-2 (0.65 mg/mL) > PKM-1 (0.35 mg/mL) > Jaffna (0.15 mg/mL). The results of HPLC quantification of anticancer compounds [beta-sitosterol (0.244%), quercetin (0.216%), kaempferol (0.013%), and moringin (0.063%)] was also in consonance with that of MTT assay. In summary, the trend observed in all the parameters tested was Jaffna > PKM-1 > PKM-2 > ODC > conventional. Thus, Jaffna variety has a better potential to combat malnutrition and cancer and must be recommended for commercial plantations.