Acúmulo de metabólitos secundários em órgãos de Passiflora edulis ao longo do desenvolvimento vegetal

Abstract

The genus Passiflora, family Passifloraceae, includes about 600 species, distributed in tropical and subtropical regions of the world. This work analyzed which are the main secondary metabolites produced by Passiflora edulis in their different organs. In addition, it investigated whether there is variation in concentrations of these substances in function of the analyzed organ and the phase of the vegetal development (juvenile, flowering and fruiting). Leaves were the organs that most accumulated phenolics/flavonoids, regardless of the plant developmental stage. Leaf extracts efficiently scavenged reactive nitrogen species (DPPH) by up to 67% while root and fruit shell extracts were more efficient in capturing reactive oxygen species (by up to 80% O2-). The activity of antioxidant enzymes catalase, ascorbate peroxidase and superoxide dismutase in leaves of P. edulis had similar profiles with maximum activity in the fruiting phase. Thin layer chromatography analysis indicated the presence of flavonoids in all extracts analysed, tannins in root extracts, and terpenes in leaves, fruit shell and root extracts. Leaf extracts at any phenological stage presented flavonoid contents that were 10-fold higher than those found in other extracts according by Brazilian Pharmacopoeia protocol. Ultra High Performance Liquid Chromatography analysis, disclosed that leaves and fruit shell extracts present nine different flavonoid C-glycosides, likely luteolin, apigenin and chrysin glycoconjugates. Extracts of fruit shell on fruiting were the most potent against Canavalia ensiformis ureases, they inhibit the enzyme activity by over 43%, whereas hydroxyurea compromised the urease activity by 35.6%. The different classes of secondary metabolites present in P. edulis plants vary in fuction of the phases of development and the organs analyzed.