Avaliação das atividades antinociceptiva e anti-inflamatória de extratos metanólicos da Annona tomentosa R.E.Fr.

Abstract

In this study, we tested the methanolic extracts and their partitions of Annona tomentosa, native specie of Brazil and popularly known as “araticum rasteiro” or “araticum de moita”. The tea from its leaves has been used as anti-inflammatory by native community. For this reason, antinociceptive and anti-inflammatory activities of A. tomentosa, from São Luís-MA, were evaluated in mice. The methanolic extracts from stem bark (ATCM) and leaves (ATFM) were prepared by maceration with methanol and their partitions from hexane (ATFM-H), dichloromethane (ATFM-D), ethyl acetate (ATFM-Ac) and butanol (ATFM-Bu) were prepared by liquid-liquid partition. The antinociceptive effect of extracts and fractions were evaluated by abdominal writhing and tail-flick tests, while the anti-inflammatory effects were evaluated by paw oedema and air pouch tests. From the tail flick, we evaluated by the possible action mechanism of A. tomentosa using antagonists and inhibitors, such as naloxone, L-NAME, glibenclamide, atropine, naltrindole and nor-binaltorphimine. The leukocyte migration and production of TNF-α and IL-1β were evaluated from the air pouch test. The methanolic extract ATFM (100 mg/kg) reduced abdominal writhing by aproximately 49% (27,8 ± 4,4 abdominal writhing). Among its fractions only ATFM-H and ATFM-D were able to reduce the abdominal writhing 42,3% (31,3 ± 5,9 abdominal writhing) and 34% (35,8 ± 7,7 abdominal writhing), respectively, in relation to negative control group. The ATFM-H showed central antinociceptive effect from the involvement of the delta opioid receptors, in the tail flick test, without promote alterations in the locomotor activity of the mice in the open field test, in relation to negative control group. The partition ATFM-D was effective in decreasing paw oedema induced by carrageenan (100 mg/kg), histamine (50 and 100 mg/kg) and serotonine (10, 50 and 100 mg/kg). O ATFM-D inhibited leukocyte migration to air pouch, at doses 50 and 100 mg/kg, in 75,8% (3,91 ± 1,2 x 106/mL) and 92,9% (1,15 ± 0,5 x 106/mL), and TNF-α production at doses of 50 and 100 mg/kg by approximately 43% (740 ± 85,7 pg/mL) and 67% (433,8 ± 52,1 pg/mL), respectively, in relation to PBS control group. The ATFM-D also reduced IL-1β production at doses of 50 and 100 mg/kg by approximately 25% (452,3 ± 52,5 pg/mL) and 35% (388,7 ± 42,3 pg/mL), respectively, in relation to PBS control group. As demonstrated by methods employed, these results demonstrate that methanolic extract of leaves from A. tomentosa presented antinociceptive and anti-inflammatory effects, suggesting its potential for therapeutic purposes.