Evaluation of Antinociceptive Activity of Ethanol Extract of Leaves of Adenanthera pavonina.

Md Moniruzzaman,Ambia Khatun,Mohammad Zafar Imam

doi:10.1155/2015/412497

Abstract

Adenanthera pavonina is a deciduous tree commonly used in the traditional medicine to treat inflammation and rheumatism. The aim of this study was to evaluate the antinociceptive activity of ethanol extract of leaves of A. pavonina (EEAP). EEAP was investigated using various nociceptive models induced thermally or chemically in mice including hot plate and tail immersion test, acetic acid-induced writhing, and glutamate- and formalin-induced licking tests at the doses of 50, 100, and 200 mg/kg body weight (p.o.). In addition, to assess the possible mechanisms, involvement of opioid system was verified using naloxone (2 mg/kg) and cyclic guanosine monophosphate (cGMP) signaling pathway by methylene blue (MB; 20 mg/kg). The results have demonstrated that EEAP produced a significant and dose-dependent increment in the hot plate latency and tail withdrawal time. It also reduced the number of abdominal constrictions and paw lickings induced by acetic acid and glutamate respectively. EEAP inhibited the nociceptive responses in both phases of formalin test. Besides, the reversal effects of naloxone indicated the association of opioid receptors on the exertion of EEAP action centrally. Moreover, the enhancement of writhing inhibitory activity by MB suggests the possible involvement of cGMP pathway in EEAP-mediated antinociception. These results prove the antinociceptive activity of the leaves of A. pavonina and support the traditional use of this plant.

Highlights

Inflammation is one of the most common physiological events that lead to chronic pain in response to tissue injury
It is possible that EEAP may not be toxic at all the doses used in this study up to 2000 mg/kg
The results revealed that naloxone reverses the antinociceptive effect of EEAP to some extent which impressed us to conceive that the opioid receptors may influence the central antinociceptive effect of EEAP through spinal and supraspinal mechanisms

Summary

Introduction

Inflammation is one of the most common physiological events that lead to chronic pain in response to tissue injury It causes a consecutive change in several cellular components including neurotrophic factors, neuropeptides, prostanoids, and kinins which are able to conduct and amplify the nociceptive perception [1]. (family: Leguminosae-Mimosaceae), a deciduous tree commonly known as “Ranjan” in Bangladesh, is an important medicinal plant found in tropical Asia, western and eastern Africa, and most islands of both the Pacific and Caribbean regions The leaf of this plant has long been used in the traditional medicine system against a wide range of diseases including inflammation and rheumatism [4, 5].

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