Abstract

A group of eighteen fruits cultivated in Ecuador were evaluated for their total soluble phenolic compounds and antioxidant activity and attempts were made to identify the group and content of phenolic compounds responsible for the antioxidant activity. In terms of total phenolic content, three groups (with <100,200-500 and >1000 mg gallic acid equivalents/100 g FW) were clearly distinguishable. RP-HPLC-DAD and/or LC-MS/MS were used to study the phenolic compounds in four Rosaceae fruits (Andean blackberry, strawberry, plum and capulí cherry), three Passifloraceae and mortiño berry. Andean blackberry contained ellagitannins, ellagic acid derivatives and cyanidin glycosides as major compounds, plus considerable amounts of (-)-epicatechin, proanthocyanidins, quercetin derivatives, gallic acid and galloyl esters. Strawberry had ellagic acid derivatives as major components followed by pelargonidin glycosides, proanthocyanidins, quercetin derivatives and galloyl esters. Plum and capulí cherry both contained chlorogenic acids among the hydroxycinnamate derivatives, (-)-epicatechin among the flavan-3-ols and similar levels of proanthocyanidins and quercetin derivatives. In addition, capulí cherry had a high concentration of (+)-catechin. Two fruits were studied for the first time: mortiño berry (Vaccinium floribundum Kunth, Family Ericaceae) and banana passion fruit or taxo (Passiflora mollissima H.B.K.). In mortiño, (-)-epicatechin and one trimer A were found. Of the flavonol glycosides, quercetin and myricetin were found as -3-O-hexosides, -3-O-pentosides and -3-O-deoxyhexosides. Chlorogenic and neochlorogenic acids together with caffeic/ferulic acid derivatives were found as predominant components among the hydroxycinnamic acids. Anthocyanins were the major class quantified in the berry. Banana passion fruit contained the monomers (E)GC, (+)-catechin, (-)-epicatechin and the rare (epi)afzelechin, and proanthocyanidin dimers and trimers (E)GC-(E)GC, (E)C-(E)GC, (E)Azf-(E)C, (E)C-(E)C-(E)C, (E)C-(E)GC-(E)C, and (E)GC-(E)GC-(E)C. The total content of proanthocyanidins was quantified as ~1955 mg/100 g FW, indicating that banana passion fruit is an excellent source of proanthocyanidins.