Desenvolvimento de sistemas in vitro visando à produção de plantas, culturas celulares e metabólitos com potencial antioxidante e antineoplásico de Pereskia aculeata Mill

Abstract

Biotechnological techniques have been used for large-scale production of plants and secondary metabolites of interest, contributing to the sustainable use of biodiversity. Additionally, the increased incidence of cancer associated with adverse effects induced by traditional chemotherapy has leading scientific research to search for new drugs of natural origin. Species from the Cactaceae family are recognized as sources of vitamins, proteins and minerals, rich in bioactive substances, and they may be considered as functional foods. Commonly known as ora-pro-nobis , Pereskia aculeata Mill. is a native cactus with high nutritional value and medicinal properties. This study aimed the establishment of different in vitro culture systems for P. aculeata to produce metabolites of medicinal and nutraceutical significance, focusing on anticancer potential. In vitro germination was established and provided epicotyl explants used in the micropropagation of the species. Buds proliferated on MS medium supplemented with BA were in vitro rooted and successfully acclimatized. High rates of total protein were determined in leaves from field and acclimatized plants. Pigmented callus cultures (PCC) were established from hypocotyl segments kept on MS medium containing Picloram. Modifications in the composition of MS medium with respect to the total content and the nitrogen source favored to optimize the pigmented calogenic biomass. Cell suspension cultures (CSC) were established from pigmented friable callus grown in liquid medium of the same composition. The pigments were characterized as betalains. PCC and CSC were submitted to extraction and quantification of total betalains. High production of betalains was verified in CSC grown in modified MS. Methanolic extracts were obtained from acclimatized and field plants, and from in vitro cultures of P. aculeata. The antioxidant action of the species was demonstrated by scavenging the DPPH radical, iron II chelating capacity and reduction of reactive oxygen species and nitric oxide levels. The anticancer potential of P. aculeata was observed in different strains of neoplastic cells. The field leaf sample showed high cytotoxicity on K562 and Jurkat leukemia cell lines. The medicinal potential of the species was associated with the presence of betalains and polyphenols, determined by HPLC-UV-MS ESI. The results confirm the nutraceutical potential of P. aculeata from in vitro produced materials, reveal the antitumor activity for tumor cell lines still not investigated and make possible the species exploration by plant biotechnology