Phytochemical screening of Psidium guajava and Carica papaya leaves aqueous extracts cultivated in Greece and their potential as health boosters

Abstract

Aim: The scope of the present study was to investigate the phytochemical profile of Psidium guajava and Carica papaya leaves aqueous extracts, from plants cultivated on Crete island in Greece. Methods: Total phenolic content (TPC) in the aqueous extracts was determined spectrometrically using the Folin-Ciocalteu (F-C) assay. The identification and quantification of different phenolic compounds in the aqueous extracts were conducted using reversed-phase high-performance liquid chromatography (RP-HPLC) analysis. Different metals were also determined (K, Fe, Zn, Ca, Mg, Pb, and Cd) to investigate the potential health claims or hazards in the water extractable infusion using inductively coupled plasma mass spectrometry (ICP-MS) method. Results: TPC in the aqueous extracts was found to be 28.0 g gallic acid equivalent (GAE)/kg dry leaves for Psidium guajava leaves aqueous extract and 15.0 g GAE/kg dry leaves for Carica papaya leaves aqueous extract. The dominant phenolic compounds in Psidium guajava leaves aqueous extract were myricetin (3,852 mg/kg dry sample) and rutin (670 mg/kg dry sample) while the dominant phenolic compounds in Carica papaya leaves aqueous extract were salicylic acid (338 mg/kg dry sample) and rutin (264 mg/kg dry sample). Different metals were also determined (K, Fe, Zn, Ca, Mg, Pb, and Cd) to investigate the potential health claims or hazards in the water extractable infusion, and it was found that no toxic metals were extracted whereas some nutritional benefits were achieved. Conclusions: Results proved that Psidium guajava and Carica papaya can be provided a strong antioxidant activity and can be used as medicinal plants.