Bioactivity, hydrophilic, lipophilic and volatile compounds in pulps and skins of Opuntia macrorhiza and Opuntia microdasys fruits

Abstract

Opuntia genus includes several species able to grow in arid regions and known for producing delicate fruits, which are far from being thoroughly characterized. Herein, fruits from O. macrorhiza and O. microdasys were divided in skins and pulps (without including seeds) and studied for chemical composition, individual phytochemicals and bioactivity. The major volatiles were camphor and ethyl acetate, while citric acid was the main organic acid. The fatty acids detected in highest percentages were linoleic acid (skins) and lauric acid (pulps); α- tocopherol was the major isoform of vitamin E. Quercetin-3-O-rutinoside and quercetin-O-(deoxyhexoside-rutinoside) were the main phenolics in fruit skins of O. macrorhiza and O. microdasys (respectively), similarly to piscidic acid in O. macrorhiza pulp (O. microdasys pulp showed no quantifiable compounds). Betanin and isobetanin were the major betalains. All samples were antioxidant (particularly O. macrorhiza), but antimicrobial activity was only detected in skins. Cytotoxicity was low in all cases. Overall, these fruits proved to be potential new ingredients for food or pharmaceutical related applications, adding value to these natural species able to grow in arid environments.Authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), C2TN (UID/Multi/04349/ 2013), L. Barros, J. Barreira and R. Calhelha contracts. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural®. Authors also thank FEDER Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio