The Apoptosis-inducing Antiproliferative Activity and Quantitative Phytochemical Profiling of Polyphenol-rich Part of Leea Aequata L. Leaves

Abstract

Aim/Objectives: Oxidative stress (OS) caused by the accumulation of free radicals in the body triggers many life-threatening diseases, including cancer. Plants are the rich source of safe and effective medicinal compounds like antioxidants that can prevent OS by scavenging free radicals. The aim of this study was to explore the chemical compositions of the methanolic extract of Leea aequata L. leaves possessed the highest antioxidant and cytotoxic activities.Methods and Materials: The Leea aequata leaves (LAL) was extracted with 80% methanol and the crude methanolic extract of LAL (CME) was successively fractionated with petroleum ether, chloroform, ethyl acetate and finally with water to get petroleum ether (PEF), chloroform (CHF), ethyl acetate (EAF) and aqueous (AQF) fraction, respectively. The antioxidant activity was evaluated by the in vitro standard spectrophotometric methods. The MTT colorimetric method was used to measure cytotoxic activity. Apoptosis was measured using fluorescein annexin V-FITC/PI staining method. GC-MS was used to investigate phytochemical compositions.Results: Among the fractions, the highest phenolic and flavonoid-rich fraction was EAF, which contained 267.05± 8.53 mg of gallic acid equivalent (GAE) and 152.98±1.96 mg of catechin equivalent (CAE)/gm of dried extract, respectively. The EAF was found to be the highest antioxidant and reducing power activities. Also, EAF had the strongest free radical scavenging activity with IC50 values of 5.11, 36.54 and 38.96 µg/mL for DPPH, hydroxyl and lipid peroxide free radicals, respectively. Moreover, EAF significantly reduced the HeLa cell proliferation and it was due to the induction of apoptosis of HeLa cells. Furthermore, GC-MS data revealed that EAF contained 17 compounds. Methyl esters of long chain fatty acid were the major chemical constituents. Interestingly, hexadecanoic acid, methyl ester; 9-octadecenoic acid (Z)-, methyl ester; 9,12-octadecadienoic acid, methyl ester (Z, Z) and phenol, 2,4-bis(1,1-dimethylethyl) are known to be antioxidant and cytotoxic. Antioxidant and anti-cancer activity were significantly correlated with the total content of phenolics and flavonoids, suggest that the fractions could be the good source of antioxidant and anti-cancer agents.Conclusion: The EAF of Leea aequata has strong polyphenolic content compared to the other fractions. The cytotoxic and antioxidant activity of Leea aequata were due to the presence of different bioactive compounds.