Anti-nociceptive effect of seed extract of Acacia tortilis in rodents

Background: Management of pain is a primary clinical concern for any pathology in medical field. Addiction liability of opioids and troublesome gastrointestinal side effects of NSAIDs leads to intensive research for compound with lesser side effects.The aim of the study to evaluate the anti-nociceptive activity of Acacia Tortilis Seed Extract (ATE) in experimental animals.Methods: First of all, animals were randomly allocated into four groups of six animals each. In acetic acid induced writhing test model, Group I (NC) served as vehicle control received saline/Tween 80 0.1%, 10ml/kg BW orally, group II (ATE-100) and III (ATE-200) received ATE in dose of 100 and 200mg/kg BW orally respectively and group IV received the standard drug diclofenac sodium in dose of 50 mg/kg BW orally. Group I to IV were same in rest of three experimental models. One additional group of standard drugs (group V) morphine sulfate in dose of 5 mg/kg BW subcutaneously (SC) was allocated for screening method hot plate and tail flick tests. In Formalin induced paw licking test, three additional groups (group V) morphine sulfate in dose of 5mg/kg BW SC, group VI- morphine+naloxone (5mg/kg SC +2mg/kg intra-peritoneally (IP) and group VII - ATE+ naloxone (200mg/kg BW orally +2mg/kg BW IP) were also made.Results: The ATE when administered orally in dose of 100 and 200mg/ kg body weight (BW), produced significant analgesic activity (P <0.01) in acetic acid induced writhing syndrome and late phase of formalin test. In the hot plate test in mice and tail flick test in rats, ATE in same doses also showed significant analgesic activity (P <0.05) which is almost equally efficacious to standard drug diclofenac sodium (50mg/kg BW orally) but far less efficacious than morphine sulfate (5mg/kg BW subcutaneous).ATE (200mg/Kg BW orally) activity did not blocked by naloxone (2mg/kg intra-peritoneal).Conclusions: ATE possesss significant anti-nociceptive activity as evidenced in all the animal models of nociception. It might exert its effect through the peripheral mechanism of analgesic action possibly by interference in biosynthesis, release and/or action of prostaglandins and leukotrienes.

Beneficial effects of methanolic extract of Indigofera linnaei Ali. on the inflammatory and nociceptive responses in rodent models

ABSTRACT Indigofera linnaei Ali. (Tamil Name: Cheppu Nerinjil) belongs to the family Fabaceae, used for the treatment of various ailments in the traditional system of medicine. In the present study, the beneficial effects of methanol extract of whole plant of I. linnaei (MEIL) were evaluated on inflammation and nociception responses in rodent models. In vitro nitric oxide (NO), lipoxygenase (LOX) and cyclooxygense (COX) inhibitory activities were also performed to understand the mode of action. MEIL at the dose of 200 & 400 mg/kg, p.o. significantly inhibited carrageenan induced rat paw volume and reduced the weight of granuloma in cotton pellet granuloma model. The results obtained were comparable with the standard drug aceclofenac. The anti-nociceptive effect of MEIL in mice was evaluated in hot plate and acetic acid induced writhing model. The plant extract significantly reduced the number of writhes and the analgesic effect was higher than that of the standard drug aspirin. However, the extract fails to increase the latency period in hot plate method suggesting that the extract produce nociception by peripheral activity. The extract produced inhibitory effect on NO, LOX and COX in concentration dependent manner. The extract exhibited pronounced and selective COX-2 inhibition. Altogether, these results suggested that the methanol extract of Indigofera linnaei could be considered as a potential anti-inflammatory and analgesic agent.

RESUMO Indigofera linnaei Ali pertence à família Leguminosae e é utilizada para o tratamento de várias doenças na medicina tradicional. No presente estudo, os efeitos benéficos do extrato metanólico da planta inteira de I. linnaei (MEIL) foram avaliados em respostas inflamatórias e nocicepção em modelos de roedores. Testes in vitro de atividade inibitória do óxido nítrico (NO), lipoxigenase (LOX) e ciclooxigenase (COX) também foram realizados para compreender o modo de ação. MEIL nas doses de 200 e 400 mg/kg, p.o. inibiu significativamente o volume da pata de rato induzido por carragenana e reduziu o peso do granuloma no modelo de pélete de algodão. Os resultados obtidos foram comparáveis ao do fármaco padrão, aceclofenaco. O efeito anti-nociceptivo de MEIL foi avaliado em camundongos no modelo de placa quente e de contorção induzida por ácido acético. O extrato da planta reduziu significativamente o número de contorções e o efeito analgésico foi maior do que o do fármaco padrão, ácido acetilsalicílico. Porém, o extrato não conseguiu aumentar o período de latência no método da placa quente, sugerindo que este produz nocicepção por atividade periférica. O extrato produziu efeito inibitório sobre o NO, LOX e COX dependente da concentração. O extrato exibiu inibição acentuada e seletiva da COX-2. No seu conjunto, estes resultados sugerem que o extrato metanólico de Indigofera linnaei poderia ser considerado como agente anti-inflamatório e analgésico potencial.