Extração, avaliação e aplicação celular de compostos fenólicos presentes na casca do pinhão Araucaria angustifolia (Bertol.) O. Kuntze

Abstract

The Araucaria angustifolia (Bertol.) O. Kuntze is found mainly in the southern region of Brazil, known by many popular names such as Brazilian pine, Paraná pine, pine, araucaria. Pine nuts mature in cones, they are large seeds that have nutritional reserves. The pine nut shell, rich in bioactive compounds, is considered unexploited agro-industrial waste, representing around 20% of the total weight of the pine nut, and is normally discarded into the environment. Bioactive compounds stand out for the properties they exert as antioxidant, anti- inflammatory and supporting agents in the treatment of diseases. In this context, the objective of this work was to evaluate the phenolic composition and antioxidant activity of in natura pine nut shell extract, through maceration and ultrasound-assisted extraction techniques, and to investigate the anticancer action of the extract on cutaneous melanoma cells of the SK-Mel-28 and A-375. The coats were separated from the seeds and dried for 24 hours at 40 °C in a forced air convection oven (Cienlab). Shells were subsequently crushed and sieved (0.210 and 0.250mm). The extracts from fresh pine nut shells were evaluated for total phenolic compounds (CFT) - by the Folin-Ciocalteu method - total antioxidant activity (AAT) - by the DPPH and ABTS radical scavenging method and antitumor activity in cutaneous melanoma cells (MC). In the extraction of total phenolic compounds (CFT), the treatments did not show a significant difference. The highest CFT content was 15.51 μg.g-1 dry mass obtained by ultrasound-assisted extraction for 30 minutes. In the evaluation of antioxidant activity by DPPH and ABTS, maceration did not show a significant difference between treatments, however, using the ultrasound method for 30 minutes, ABTS showed a significant difference (p<0.05), with 1202, 44 μM TEAC.g-1, which was subsequently applied to MC cells. Anticancer activity was evaluated by the cell viability method (MTT) by exposing melanoma cells to the crude extract and by serial dilution for 24 hours. In treatments with SK-Mel-28 cells, they did not show cell inhibition activity. Treatment on A-375 cells resulted in a significant decrease in cell viability, presenting antitumor activity at the concentrations tested (p<0.001); (p<0.0001), when compared to the control, except in the 1:100 dilution, where the treated cells did not change when compared to the control. The concentrations where the dilution factor of the Araucaria angustifolia extract were 1:1000 and 1:10 were able to inhibit the growth of tumor cells by approximately 30% in 24 hours of treatment. At concentrations where the dilution factor was 1:1 and with crude extract, a higher rate of cytotoxicity was observed, showing a significant reduction in cell proliferation with a percentage below 50% in relation to the control in these treatments. The extract for A-375 cells demonstrated effective results in preventing cell migration, potentially as a supporting agent for the treatment of cutaneous melanoma.