Caracterização fitoquímica e avaliação da atividade antioxidante de materiais obtidos in vivo e produzidos in vitro de Passiflora alata Curtis

Abstract

Passiflora alata Curtis, known as sweet passion fruit, has great agronomic interest due to its sweet fruits and exuberant flowers. It is considered a medicinal plant, recognized by the Brazilian Pharmacopeia, and used as a raw material for herbal medicines and cosmetics. Studies have identified anxiolytic, antioxidant, anti-inflammatory activities, among others, mainly associated with the presence of flavonoids, saponins and alkaloids in their leaves and fruits. The production of these bioactive compounds using plant tissue culture techniques has been successfully achieved in several species. Thus, the objective of this work was to evaluate the production of bioactive compounds and the antioxidant potential of in vivo and in vitro materials of P. alata materials. In vitro plants were obtained by seed germination on MS ½ medium. Friable calluses were induced from leaf segments excised from micropropagated plants and cultured on MSM medium supplemented with 28.9 μM picloram (PIC), in the presence or absence of light. Additionally, friable calluses maintained in the absence of light were used to induce cell suspension cultures. For the establishment of adventitious roots cultures, proximal and distal root segments were excised from micropropagated plants or from those derived from in vitro germination, and cultured in the presence of different concentrations of the auxins AIB, AIA and ANA at 25°C or 30°C. Root multiplication was observed from proximal segments excised from plants derived from in vitro germination, in the presence of 5.7 μM AIB, maintained at 25°C. Phytochemical analysis of leaf extracts from in vivo, acclimatized and in vitro-grown plants, as well as of extracts of calluses maintained in the presence or absence of light, was carried out by thin-layer chromatography. Flavonoids and alkaloids were detected in leaf extracts, whereas saponins were observed in all analyzed materials. Leaf extracts were also analyzed by HPLC-UV-DAD and HPLC-EM, in which several compounds could be detected, including the flavonoids vitexin-2''-O-rhamnoside and isoorientin, and the saponin quadranguloside. The same materials were investigated in terms of their antioxidant capacity using the DPPH scavenge and the iron chelating assays. All extracts showed antioxidant capacity, with the greatest potential observed in leaf extracts. On the other hand, calluses extract maintained in the absence of light displayed low antioxidant capacity. These results revealed the potential of biotechnological systems for the production of bioactive compounds in P. alata.