Análise fitoquímica e avaliação de atividades biológicas de plantas in vivo e materiais obtidos in vitro de cultivares brasileiras de Arachis hypogaea L. (amendoim)

Abstract

Peanut (Arachis hypogaea L.), that belongs to Fabaceae family, is the fourth most consumed oilseed in the world and its seeds are highly energetic, containing lipids, proteins, vitamins, and carbohydrates. Although several biological activities have already been observed in extracts from roots, leaves, seeds and teguments, the allelopathic and antitumor activities have been less studied. In this work, these activities were investigated in crude extracts, partitions and fractions of in vivo plants and in vitro plant materials from five Brazilian Arachis hypogaea cultivars (IAC 886, IAC Caiapó, IAC Tatu ST, IAC 8112 and BR-1). Trans-resveratrol, a polyphenol widely related to biological activities, was also quantified in the samples. In order to obtain in vitro materials, the influence of different types of explants, temperature, and light qualities was analyzed. The friable calluses developed from explants of leaf segments grown on MS medium supplemented with 1.25 μM PIC at 25±2ºC under fluorescent light or association of blue and red LEDs were selected for comparison with in vivo materials. In the evaluation of the allelopathic activity, friable calluses of cv. BR-1 maintained under the association of blue and red LEDs and seed extracts of cultivar BR-1, the dichloromethane partition, and fractions dichloromethane: acetone (1:1) and dichloromethane:acetone (1:4) caused the highest inhibition of growth and seed germination of Lactuca sativa. The dichloromethane partition also inhibited the growth of some weed species for A. hypogaea (Commelina benghalensis and Ipomoea nil) plantations. For the study of anticancer activity, cancer cells (K562, PC3, MCF-7 and A549), peripheral blood mononuclear cells (PBMC) and mouse fibroblast cells (NIH-3T3) were used. The extract of seeds with tegument of cv. BR-1, its dichloromethane partition, the dichloromethane:acetone fraction (1:1) of this partition and the crude extract from calluses of cv. IAC 886 showed higher toxicity to tumor cells, especially to the chronic myeloid lineage (K562), than to CMNSP or NIH373 cells. In the phytochemical analysis, the tegument of cultivar BR-1 was the material that presented the highest concentrations of trans-resveratrol (94.55±2.56 μg/g fresh weight). Ultraviolet elicitation resulted in an increase in trans-resveratrol content in aerial parts of the cv. IAC Tatu ST (up to 32.18±0.49 μg/g fresh weight)