Analgesic and hypnotic activities of Laghupanchamula: A preclinical study

Abstract

Background:In Ayurvedic classics, two types of Laghupanchamula -five plant roots (LP) have been mentioned containing four common plants viz. Kantakari, Brihati, Shalaparni, and Prinshniparni and the fifth plant is either Gokshura (LPG) or Eranda (LPE). LP has been documented to have Shothahara (anti-inflammatory), Shulanashka (analgesic), Jvarahara (antipyretic), and Rasayana (rejuvenator) activities.Aim:To evaluate the acute toxicity (in mice), analgesic and hypnotic activity (in rats) of 50% ethanolic extract of LPG (LPGE) and LPE (LPEE).Materials and Methods:LPEG and LPEE were prepared separately by using 50% ethanol following the standard procedures. A graded dose (250, 500 and 1000 mg/kg) response study for both LPEE and LPGE was carried out for analgesic activity against rat tail flick response which indicated 500 mg/kg as the optimal effective analgesic dose. Hence, 500 mg/kg dose of LPEE and LPGE was used for hot plate test and acetic acid induced writhing model in analgesic activity and for evaluation of hypnotic activity.Results:Both the extracts did not produce any acute toxicity in mice at single oral dose of 2.0 g/kg. Both LPGE and LPEE (250, 500, and 1000 mg/kg) showed dose-dependent elevation in pain threshold and peak analgesic effect at 60 min as evidenced by increased latency period in tail-flick method by 25.1-62.4% and 38.2-79.0% respectively. LPGE and LPEE (500 mg/kg) increased reaction time in hot-plate test at peak 60 min analgesic effect by 63.2 and 85.8% and reduction in the number of acetic acid-induced writhes by 55.9 and 65.8% respectively. Both potentiated pentobarbitone-induced hypnosis as indicated by increased duration of sleep in treated rats.Conclusion:The analgesic and hypnotic effects of LP formulations authenticate their uses in Ayurvedic system of Medicine for painful conditions.

Cobra neurotoxin produces central analgesic and hyperalgesic actions via adenosine A1 and A2A receptors

“… 28 It is a common model of thermal-induced nociception used to evaluate central action. 29 Therefore, it is a quick and safe method to evaluate central effect of CNT. Peripheral nerve injury models include chronic constriction injury model, partial sciatic nerve ligation model, and spinal nerve ligation, which rely on traumatic injury to a single nerve, but they differ not only in duration and magnitude of sensory changes, signs of spontaneous pain but also in technical difficulty and reproducibility.…”