Biological activity of phenolics enriched extracts from industrial apple pomace

Abstract

Apple processing industries around the globe generate huge quantity of pomace as waste material, whose sustainable and cost-effective utilization continually being attempted. In general, industrial apple pomace is a conglomeration of different varieties, however, rich in array of inherited nutritional and phytochemical constituents. In present study, aqueous-ethanol, -methanol and -acetone mediated extractions of phenolics from industrial apple pomace was performed. The obtained extracts from respective solvents were further partitioned with ethyl acetate. The phytochemical evaluation of ethyl acetate fractionated aqueous acetone fraction (APA1), aqueous ethanol fraction (APE1) and aqueous methanol fraction (APM1) by high pressure liquid chromatography and electrospray-ionization quadrupole time-of-flight tandem mass spectrometry showed the presence of phloridzin, phloretin, quercitrin and quercetin as major constituents. The cytotoxic effects of APA1, APM1, and APE1 fractions were evaluated against human cancer cell lines i.e. cervical squamous cell carcinoma (SiHa), oral carcinoma (KB) and colorectal adenocarcinoma (HT-29) cell lines. Significant differences were obtained for oral cancer cells in time and dose dependent manner. Cytotoxicity data validated by clonogenic cell survival assay showed significant inhibition of KB cancer cells by APA1 and APE1 after 24 and 36 h. Caspase 3/7 activity of fractions was also found to be increased in time dependent manner. Furthermore, the flow cytometer analysis revealed that KB cells follow apoptotic and necrotic mechanism for cell death after treatment with APA1 and APE1 fractions for 24 and 30 h. Results also showed significant nitric oxide inhibition in lipopolysaccharide– interferon gamma stimulated mice peritoneal macrophages at different concentrations. Present study established that industrial apple pomace indeed has substantial amount of bioactive phenolics that can be bioprocessed to develop variety of health supplements.