In Vitro Antioxidant Activities of Phenols and Oleanolic Acid from Mango Peel and Their Cytotoxic Effect on A549 Cell Line
College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 10048, China
School of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
Authors to whom correspondence should be addressed.
Academic Editor: Susana M. Cardoso
Molecules 2018, 23(6), 1395; https://doi.org/10.3390/molecules23061395
Received: 15 May 2018 / Revised: 5 June 2018 / Accepted: 7 June 2018 / Published: 8 June 2018
(This article belongs to the Special Issue The Antioxidant Capacities of Natural Products)
Mango peel, the main by-product of juice processing, possesses appreciable quantities of bioactive phenolic compounds and is worthy of further utilization. The present work reports for the first time the HPLC analysis and in vitro antioxidant evaluation of mango peel phenols (MPPs) and their cytotoxic effect on the A549 lung cancer cell line. These results indicated that mango peel has the total phenolic content of 723.2 ± 0.93 mg·kg−1 dry mango peel (DMP), which consisted mainly of vanillic aldehyde, caffeic acid, chlorogenic acid, gallic acid, procyanidin B2 and oleanolic acid. Antioxidant assays showed that MPPs had strong antioxidant activities, with 92 ± 4.2% of DPPH radical scavenging rate, 79 ± 2.5% of ABTS radical inhibition rate and 4.7 ± 0.5 μM Trolox equivalents per kg−1 DMP of ferric reducing power. Gallic acid possess a stronger antioxidant capacity than other phenols. In vitro cytotoxic tests suggested that mango peel extract (MPE) had an IC50 value of 15 mg·mL−1 and MPPs had a stronger inhibitory effect on the A549 cell line. Oleanolic acid exhibited the strongest cytotoxicity, with an IC50 value of 4.7 μM, which was similar with that of the positive control 5-fluorouracil.