Estudo Químico e Avaliação da Toxicidade e das Propriedades Antioxidante e Anticolinesterásica de Lindackeria paraensis Kuhlm. (Flacourtiaceae).

Abstract

This work describes the isolation of some chemical constituents besides the evaluation of toxicity against Artemia salina Leach, total phenolic content, using Folin-Ciocalteu reagent, inhibition of acetylcholinesterase and antioxidant (DPPH) activities of extracts of leaves of Lindackeria paraensis Kulhm (Flacourtiaceae). In the antioxidant assays, some of the extracts and chromatographic fractions tested showed high total phenolic content, when compared to positive controls used (ascorbic acid, α-tocopherol and BHT) free radicals scavenger. In the anticholinesterasic assays, some these extracts were effective to inhibit the enzyme. On the other hand, in the toxicity assay against Artemia salina, among samples tested, only three were non toxic (LC50 upper to 1000 mg/mL) and seven showed high toxicity (LC50 under to 500 mg/mL), suggesting that this species must be evaluated for other activities, such as insecticidal, pesticide, cercaricidal and others that dependent of citotoxicity. Phytochemical study with some these active extracts conduced to the isolation of two pentacyclic triterpenes (fridelin and fridelinol) and four flavones (5-Hydroxy-7,4 -dimethoxyflavone, 5,4 -Dihydroxy- 7-methoxy-flavone, 5,7,4 -Trihydroxy-3 -methoxyflavone, and 5,4 -Dihydroxy-7,3 - dimethoxyflavone). All isolated compounds were identified on the basis of the NMR spectral data and by comparison with literature data and are being described for the first time in the genus Lindackeria. The flavones identified as 5,7,4 -trihydroxy-3 -methoxyflavone, 5- hydroxy-7,4 -dimethoxy-flavone and 5,4 -Dihydroxy-7-methoxyflavone free scavenging radicals against DPPH and 5,4 -dihydroxy-7-methoxyflavone inhibited the action of anticholinesterase enzyme.