Phenolic composition and cell-based biological activities of ten coloured potato peels (Solanum tuberosum L.)

The present study provides an in-depth characterisation of the non-anthocyanin and anthocyanin phenolic compounds of potato peels from ten coloured potato varieties. Furthermore, the underexplored bioactive potential (antioxidant, cytotoxic and anti-inflammatory capacities) of the studied peels is comprehensively analysed. Among non-anthocyanin phenolics, caffeic and a caffeoylquinic acid were found in the highest concentrations in all samples, which also showed the presence of O-glycosylated flavonol derivatives and polyamine derivatives. Acylated anthocyanins were identified in red and purple varieties, being pelargonidin, peonidin, and malvidin the most prominent aglycones. All samples revealed antioxidant and antitumor activities, and no toxic effect. The extract of the Rosemary variety presented the best antioxidant and antitumor outcomes and was the only sample to reveal anti-inflammatory activity. These results are valuable for the food-industry by adding value to an important bio-residue, particularly concerning its potential as natural ingredients in novel food and pharmaceutical formulations.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/ MCTES to CIMO (UIDB/00690/2020); the national funding by FCT, P.I., through the institutional scientific employment program-contract for L. Barros, Maria Inês Dias and C. Pereira contracts; to FEDER-Interreg España-Portugal programme through the project TRANSCoLAB 0612_TRANS_CO_LAB_2_P; to the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural ®; and also to the Ministry of Education, Science and Technological Development of Republic of Serbia (451-03-68/2020-14/200007). GIP-USAL is financially supported by the Spanish Government through the project AGL2015-64522-C2-2-R. S. Sampaio acknowledges CAPES Foundation (Ministry of Education, Brazil) for her PhD grant no. 99999.001423/2015-00.info:eu-repo/semantics/publishedVersio

Phenolic and bioactive profiles of ten colored potato peels

The pharmaceutical and food industries have been exhaustively prospecting the use of natural products as sources of bioactive molecules to substitute synthetic drugs and food additives. Withal, the valorization of bio-residues abundant in bioactive phytochemicals that are commonly rejected, like potato peels, could pitch in to the development of more sustainable, both economically and socially, productive chains [1]. In this study an unprecedented in-depth characterisation of the non-anthocyanin and anthocyanin phenolic compounds of potato peels from ten colored potato varieties was performed. Beyond that, the antioxidant, cytotoxic and anti-inflammatory potentials of the samples were explored for the first time. Among non-anthocyanin phenolics, caffeic and a caffeoylquinic acid were found in the highest concentrations in all samples, which also showed the presence of ​O-​glycosylated flavonol derivatives and polyamine derivatives. Acylated anthocyanins were detected in red and purple varieties, being pelargonidin, peonidin, and malvidin the most prominent aglycones. All samples displayed antioxidant and antiproliferative actions, and no toxicity towards non-tumor cell lines up to the concentration of 304 μg/mL. The Rosemary variety presented the best antioxidant and antitumor activities, and was the only sample to show anti-inflammatory effects. Such promissory findings support the exploitation of potato peels as valuable sources of bioactive compounds and as natural additives in functional food formulations.S. Sampaio acknowledges CAPES Foundation (Ministry of Education, Brazil) for her PhD grant no. 99999.001423/2015-00. ​R. C. G. Corrêa is a research grant recipient of Cesumar Institute of Science Technology and Innovation (ICETI). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019); the national funding by FCT, P.I., through the institutional scientific employment program-contract for L. Barros and Maria Inês Dias contracts; to FEDER-Interreg España-Portugal programme through the project 0377_Iberphenol_6_E and and TRANSCoLAB 0612_TRANS_CO_LAB_2_P,GIP-USAL is financially supported by the Spanish Government through the project AGL2015-64522-C2-2-R.info:eu-repo/semantics/publishedVersio