Cultura in vitro de Arachis repens Handro: análise fitoquímica e avaliação da atividade antioxidante de materiais obtidos sob diferentes qualidades de luz

Abstract

Arachis repens Handro, commonlyknown as perennial peanut grass, is used as an ornamental, forage and ground cover, with vegetative reproduction and very low seed production. The present work aimed at establishing callus culture systems, as well as the characterization ofthe phytochemical profile and the antioxidant potential of extracts from in vitro materials produced under different light qualities.The establishment of in vitro plants was accomplished from stem segments excised from plants grown in greenhouse, after pre-treatment with Icon Garden® insecticide for three days, followed by inoculation on MS medium containing Agrimicina® at 300 mg/L, without growth regulators. These cultures were incubated at 30 ± 2 ° C in growth chambers under white fluorescent light or under red, blue, white or mixed (red + blue) LEDs.Incubation under red LEDs resulted in a significant increase in plant height. For callus induction, stem segments excised from in vitro plants were cultured on MS medium supplemented with 13.6 μM TDZ and incubated under the same light conditions. Nodal segments maintained under fluorescent white light gave rise tocompact or friable calluses.Internodal segments also originated friable, compact or mixed callus, at different frequencies The callus presented different morphogenic responses.In the evaluation of callus production under different types of LEDs, a higher percentage of compact calluses was observed from internodal segments cultured under white LED. However, the highest production of friable callus occurred in response to the incubation under red LED. On the other side, cultivation under blue LED resulted in a higher percentage of mixed calluses. The phytochemical characterization of the different materials of A. repens was performed by means of chromatographic analyzes. The TLC analysis allowed the identification of resveratrol, as well as the presence of other groups of substances. The results obtained by HPLC confirmed the presence of trans-resveratrol in the extracts of callus incubated under the different types of LEDs, and the highest content was detected in the extracts of calluses derived from nodal segments incubated under mixed LED. The evaluation of the antioxidant potential of the extracts of the in vitro-derived materials was carried out by DPPH assay and total phenolic content was determined by the Folin-Ciocalteau method. The ethanolic extracts of calluses derived from nodal and internodal segments incubated under mixed LED showed higher concentration of total phenols and higher antioxidant potential.The use of LED's in tissue culture induced an increase in the quality of the plants and resulted in the addition of bioactive substances and antioxidant activity