Lacistema pubescens MART.: perfil fitoquímico e atividades biológicas

Abstract

Lacistema pubescens Mart. (Lacistemataceae), an arborea native species, is distributed in several Brazilian states and known popularly as “espeto-vermelho, canela – vermelha, sabonete e cafezinho”. This work describes the phytochemical profile and the antioxidant, antimicrobial, anti-leishmanial, antitumor, anti-inflammatory and antinociceptive activities of the leaves of L. pubescens. The antioxidant activity was evaluated by four different methods and performed with the crude methanol extract (EBM) and the hexane (PHEX), dichloromethane (PDCM), ethyl acetate (PAcOEt) and hydromethanolic (PHM) partitions. By the DPPH method, all samples were effective in inhibiting the radical, particularly PHM (IC50 1.8 μg /ml), by the β-carotene/linoleic acid system, the best answer was shown for PHEX (IC50 22.71 μg/ml), by the TBA method, the sample that best managed to inhibit lipid peroxidation was the PHM and when evaluated for the reducing power, the samples showed no activity. The antimicrobial activity, used to determine the MIC was performed with the EBM and partitions on the strains Staphylococcus aureus, Pseudomonas aeruginosa, Shigella dysenteriae, Salmonella typhimurium, Escherichia coli, Enterobacter cloacae and Enterococcus faecalis. The best response was for the partitions with MIC values of 125 μg/mL, as follows: PDCM for Enterococcus faecalis; PAcoEt for PHM and Enterobacter cloacae. The leishmanicidal activity was observed in promastigotes of Leishmania amazonensis, L. major, L. braziliensis and L. chagasi. PHEX was the sample that showed the most significant IC50 among the four species tested. For the antitumor activity observed by MTT method, PHEX and PAcOEt were active for HL60 and PDCM for MCF-7 tumor cell lines. On the other hand, all extracts were resistant to Jurkat. The antinociceptive and anti-inflammatory potential of L. pubescens were investigated in vivo. Three models for pain, with different modulation mechanisms were used. In the writhing test, EBM and all partitions were effective in suppressing pain. In the formalin test, on central origin pain, PHEX and PDCM were active and on inflammatory pain, EBM, PHEX and PDCM were active. In the tail flick test, the samples did not alter the latency period. To assess the anti-inflammatory activity, the ear edema model was used. EBM and PHEX when administered orally were not capable to reduce inflammation, but PHEX, administered topically, suppressed the edema by 88%. Major compounds like triterpenes, flavonoids and sterols found in the samples could be responsible for the activities found for L. pubescens.