The nutraceutical properties of Punica granatum L. are not restricted to the edible portion of the fruit but also to the peels and
seeds, flowers, leaves, and tree bark. The recovery and valorization of the peel and seeds (ca. 50% of the whole fruit), besides
the positive environmental impact, can be viewed as a source of natural bioactive compounds. Thus, the bioactive properties of
extracts of pomegranate peel and seeds from Acco and Wonderful known cultivars, as well as of the novel Big Full cultivar,
were evaluated. The dried and ground pomegranate by-products were submitted to a conventional solid/liquid extraction with
ethanol/water mixtures (0%, 25%, 50%, and 75% of EtOH, v/v). The obtained extracts were characterized in terms of total
phenolic compounds (TPC), total flavonoids (TF), and antioxidant activity (AA), determined by the DPPH radical scavenging
activity and expressed as IC50 (half maximum inhibitory concentration). With the exception of the Acco cultivar, the
extraction yield (EY) was higher for peels, whose extracts showed higher TPC, TF, and IC50 (lower AA). The extracts obtained
from the by-products of the Big Full cultivar had a statistically higher overall bioactive potential (TPC: 0.36 mg GAE/mg
extract; TF: 0.031 mg CATE/mg extract; IC50: 0.51 mg/mL) compared to the other two studied cultivars. Furthermore, the EY
was enhanced by solvents richer in ethanol (50-75%), allowing obtaining extracts richer in TPC and TF with higher AA.
Finally, it was shown that EY combined with bioactive data allowed a satisfactory principal component unsupervised
differentiation of the pomegranate extracts according to the type of by-product used.
This work was supported by the Foundation for Science and
Technology (FCT, Portugal) through national funds to the
research units CEB (UIDB/04469/2020), CERNAS (UIDB/00681/2020), and CIMO (UIDB/00690/2020) as well as to
the Associate Laboratory SusTEC (LA/P/0007/2020). The
European Regional Development Fund, under the Norte2020
Program funded BioTecNorte operation (NORTE-01-0145-
FEDER-000004) and funded MobFood operation (LISBOA-
01-0247-FEDER-024524). Lara Campos acknowledges the
research grants (CEB-BI-14-2019) and (FCT-IPC-i2A-CERNAS/
Escola de Verão/BI-01-08), and Luana Seixas acknowledges
the research grant (FCT-IPC-i2A-CERNAS/Escola de
Verão/BII-01-07), all provided by FCT.
