Structural elucidation of phenolic compounds isolated from Opuntia littoralis and their antidiabetic, antimicrobial and cytotoxic activity

Abstract

Cactaceae plants are widely used in folk medicine, food and pharmaceutical fields. Opuntia littoralis (Cactaceae) is a wild plant contains many active phytochemical constituents. Chromatographic techniques and spectroscopic analysis were used for the isolation and identification of the compounds. Cladodes and fruits extracts revealed the presence of tannins, carbohydrates and/or glycosides in ethanol, 70% ethanol and water extracts. Flavonoids were present in ethyl acetate, chloroform, ethanol, 70% ethanol and water extracts. Sterols and/or terpenes were detected in diethyl ether extract. 8-Carbomethoxy-5‑hydroxyl‑6-methylisoflavone was isolated from cladodes extract, while Kaempferol-3-O-rhamnoside-7-O-glucoside and Luteolin were isolated from fruits juice. Kaempferol, quercetin, gallic acid, ferulic acid, and chlorogenic acid were isolated from both cladodes extract and fruit juice. These compounds are isolated from this plant for the first time. The antidiabetic and cytotoxic activity was evaluated in vitro using ELISA reader. Antimicrobial activity was achieved using agar methods. Cladode successive extracts showed strong antimicrobial activity against some strains of bacteria and fungi. Fruit juice showed better antimicrobial effect than the fruit ethanolic extract, which possessed antidiabetic activity only. The cladode and fruit extracts showed low cytotoxic activity against breast carcinoma cell line (MCF-7). Further in vivo biological studies are needed to prove its therapeutic value.