Antioxidant and Anticancer Activity of Opuntia elatior Mill. Ethanol Extract and the Fractions

Abstract

Opuntia elatior Mill. (OpE)) is a cactus plant and has been empirically used to treat cancer and diseases caused by oxidative stress. Several studies showed that the secondary metabolites in this plant could also be developed into a lead compound to produce new single-compound drug candidates. Therefore, this study aimed to analyze the effect of phenolic and flavonoid levels in OpE on antioxidant and anticancer activity in vitro. OpE Ethanol Extract (EE) was fractionated using various solvents, including n-hexane (HF), Ethyl Acetate Fraction (EAF), and Methanol Fraction (MF). The extract and fractions were then tested for Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) as well as antioxidant activity using radical cation (ABTS) and Ferric Reducing Antioxidant Potential (FRAP). Anticancer testing was performed using MTT reagent against cervical cancer cells (HeLa), breast cancer cells (T47D), and colon cancer cells (WiDr). The results showed that EAF had the highest TPC levels (9.84 ± 0.55 mg GAE/g) compared to other fractions and had the second highest TFC levels (11.99 ± 0.79 mg QE/g) after HF. The high TPC and TFC in EAF were directly proportional to antioxidant activity tested using FRAP with IC50 value of 106.72 ± 1.60 µg/mL. Furthermore, it had the best anticancer activity against HeLa (IC50 693.61 ± 50.63 µg/mL) and WiDr (IC50 627.69 ± 36.27 µg/mL) compared to EE, HF, and MF. Based on the results, phenolic and flavonoid compounds in EAF could increase antioxidant and anticancer activities. These compounds were also believed to play a major role as anticancer agents for WiDr and HeLa.