DIFFERENTIAL BIOACTIVITY IN UVILLA (Pourouma cecropiifolia): PEEL CONCENTRATES ANTIOXIDANTS, WHEREAS PULP INHIBITS GLYCEMIC AND LIPID ENZYMES in vitro

Amazonian fruits are often valued for their antioxidant capacity, but the bioactivity of different tissues and its relation to digestive enzyme inhibition remain poorly characterized, particularly in Peruvian species. People consume uvilla (Pourouma cecropiifolia) only as pulp, discarding the peel, and, to our knowledge, no study has compared the enzyme-inhibitory potential of its fractions. This study compared the antioxidant profile and in vitro inhibition of glycemic (α-amylase, α-glucosidase) and lipid (pancreatic lipase) enzymes among uvilla pulp, pulp + peel, and peel, and evaluated whether fruit part or geographic origin explains this variation. We collected mature fruits at nine sites across three Peruvian regions (Loreto, Ucayali, and Madre de Dios) and separated them into three fractions (pulp, pulp + peel, and peel). We assayed freeze-dried 80% methanol extracts for total phenolic compounds (TPC), monomeric anthocyanins, antioxidant capacity (ABTS, FRAP, ORAC), and enzyme inhibition (IC₅₀ values). We applied nested linear mixed models, Spearman correlations, and principal component analysis. The peel contained higher concentrations of antioxidant compounds than the pulp: 139.8 vs. 14.2 mg GAE/g freeze-dried sample (TPC), 20.5 vs. 0.02 mg C3GE/g freeze-dried sample (anthocyanins), and 1478 vs. 109 µmol TE/g freeze-dried sample by FRAP. Enzyme inhibition followed a different pattern. Pulp was the most potent fraction against α-amylase (IC₅₀ 0.21 mg GAE/mL vs 0.49 mg GAE/mL for pulp + peel and 0.53 mg GAE/mL for peel) and, together with pulp + peel, against pancreatic lipase (0.23 and 0.22 vs 0.37 mg GAE/mL for peel), despite containing one-tenth of the phenolics. All fractions strongly inhibited α-glucosidase (IC₅₀ 0.028-0.035 mg GAE/mL). Phenolics, anthocyanins, ABTS, and FRAP correlated positively with α-amylase and lipase IC₅₀ values (ρ = 0.65-0.85, p < 0.001), indicating that richer profiles inhibited less. The fruit part explained 88-91% of the variation in phenolics, anthocyanins, ABTS, and FRAP, compared with 1-3% for region and site within region, and 26 of 27 site-by-fraction profiles clustered by fruit part. These results reveal differential bioactivity in uvilla; the peel is the antioxidant reservoir, whereas the pulp more potently inhibits α-amylase and lipase, and antioxidant capacity did not predict enzyme inhibition. The combination of strong α-glucosidase and moderate α-amylase inhibition suggests potential for postprandial glycemic control, and this complementarity favors using the whole seedless fruit, rather than the peel alone or pulp, as a functional ingredient. UPLC-MS phenolic identification and bioaccessibility studies are needed to attribute these activities to specific compounds. This study was funded by the National Program for Scientific Research and Advanced Studies (PROCIENCIA, by its Spanish acronym), as part of the project Interinstitutional Alliances for Doctoral Programs – Phase II: Nutrition, Contract No. PE501084302-2023-PROCIENCIA-BM.