Caracterização química e testes de atividade biológica in vitro em abacaxizeiros silvestres

Abstract

Chemical characterization and biological activity tests of plants are important approaches to drug discovery, rational use of elements of our biodiversity in view of the variety of plants reflects the diversity of their secondary metabolites and therapeutic potential. Brazil is an invaluable source of natural resources to obtain drugs, however, little study has been done on the pharmacological potential of native species. The Bromeliaceae family includes about 58 genera and about 3,352 species. Brazil comprises about 40% of the total species with Ananas comosus being the best known. Some plants of this family are used for the treatment of various diseases and there are reports on the presence of secondary metabolites such as triterpenoids, steroids, flavonoids, glycerols, cinnamic acid derivatives and others. This study aimed to know the chemical composition and biological activities of accessions and hybrids of different botanical varieties of Ananas genus in partnership with (EMBRAPA). The leaves of the harvested specimens were dried, ground, and subjected to an extraction procedure with methanol and were pre-selected via the screening and biological screening in order to obtain the best species profile. Three accessions and one hybrid were selected, they were subjected to extraction with methanol, then partitioned with solvents of different polarities. Artemia salina lethality, antioxidants and acetylcholinesterase activity tests were performed. The chromatographic fractionation of the species with better chromatography profile was performed using different techniques. The results revealed that 21 collected accessions have different secondary metabolites, and a wide variation among themselves showing no standard. In relation to biological testing several accessions showed lethality to Artemia salina, antioxidants and acetylcholinesterase activity. The results indicate that extracts of accessions contain active constituents that present such activities confirming its biological potential. As a result of preliminary studies the accessions BGA-739, BGA-804, BGA-820 and hybrid HE were selected for further study, and biological tests were conducted. The BGA- 804 access, chloroform fractions (CL) and ethyl acetate (ACT) has been shown to have high potential antioxidant represented by the EC50 in µg.ml-1 804-CL (203,5±0,528) e 804-ACT 192,5±0,193, lethality represented by the LC50 in µg.ml-1 804-CL (69,3±0,47) and 804-ACT (87,7±0,49) and inhibition of the enzyme cholinesterase in % 804-ACT (53.230 ± 4,44). Fractionation, chemical profile by HPLC / DAD and chemical characterization of the BGA-804 access, resulted in the finding of the presence of phenolic compounds, flavonoids and the isolation and identification of daucosterol originating from 804 CL fraction.