LAUSR

ETHNOPHARMACOLOGICAL RELEVANCE Sphenodesme involucrata var. paniculata (C. B. Clarke) Munir is native as well as endemic to South India. Its leaves are used in folklore medicine to treat pain and rheumatism. OBJECTIVE This study was aimed to investigate the chemical characterization, anti-nociceptive and mode of action underlying the anti-inflammatory effects of methanol extract of S. involucrata leaves (MESi). METHODS Phytoconstituents of MESi was analyzed using colorimetric and liquid chromatography-mass spectrometry (LC-MS) methods, and the oral acute toxicity was evaluated in mice up to 2000 mg/kg. The anti-nociceptive effect was evaluated in hot plate and writhing tests; whereas the anti-inflammatory effect was investigated using carrageenan, cotton pellet and lipopolysaccharide (LPS)-induced peritonitis models at doses of 100, 200 and 400 mg/kg. Additionally nitric oxide (NO) and inflammatory cytokines levels were also evaluated. RESULTS MESi exhibited the high content of phenolics and flavonoids as well as compounds like austricine, benzylglucosinolate, gossypin, justicidin B and cirsimarin were detected in LC-MS. In the acute toxicity study, oral administration of MESi did not cause any toxic effect and mortality up to 2000 mg/kg body weight in mice. In the anti-nociceptive tests, MESi augmented the latency period at higher dose (400 mg/kg), on the other hand attenuated writhings at the dose of 400 mg/kg by 87.87% (p < 0.001). In the carrageenan induced paw oedema MESi significantly inhibited the oedema formation at dose 400 mg/kg by 32.1%; besides, anti-inflammatory effect was registered in the cotton pellets-induced inflammation model at doses 200 and 400 mg/kg by 27.09% (p < 0.001) and 35.47% (p < 0.001) respectively. On the other hand, MESi appreciably reduced leukocyte, neutrophils infiltration, nitric oxide, TNF-α and IL-1β levels and increased the IL-10 level in the (LPS)-induced peritonitis model. CONCLUSION The results conclude that MESi has no acute toxic effect and it demonstrated potent anti-nociceptive and anti-inflammatory activities. Its anti-nociceptive activities are probably mediated through peripheral and central mechanisms. The anti-inflammatory effect of MESi involved the inhibition of neutrophils migration and the modulation of Th1 and Th2 cytokines, besides the attenuation of production of PGE2 and NO. LC-MS analysis revealed the predominant presence of the austricine, benzylglucosinolate, gossypin, justicidin B and cirsimarin compounds, which are possibly involved in the anti-nociceptive and anti-inflammatory effects of MESi. The current study provided supportive evidence for the folklore use of S. involucrata in the treatment of pain and inflammatory conditions.