Study On Analgesic Effect And Percutaneous Permeation Of Ginsenoside Rg3 In Mice Pain Model

ObjectiveGinsenoside Rg3?Rg3?is one of the most active components extracted from Panax ginseng.It has potential active in analgesic.Topical analgesic preparation can produce a stable analgesic effect,if it was onto the pain site according to the degree of pain.In this paper,we used a variety of mice models to study the Rg3 analgesic effect.Amino acid neurotransmitters content was measured to study its mechanism in tumor compression pain model.To investigate the percutaneous permeation character of Rg3 and the effects of different permeation enhancers in vitro.Besides,the quality of Rg3 gel and its analgesic effect were studied.MethodsAcetic acid-writhing model,formalin model and tumor compression pain model of mice were established,writhing times,time of licking paw and threshold of mechanical withdrawal were measured to evaluate the analgesic effect of Rg3,respectively.Then,the effects of Rg3 on excitatory amino acids?EAAs?and inhibitory amino acids?IAAs?were detected by HPLC-FLD for the sampIes ertracted from mice brain tissues of tumor compression pain model.The apparent solubility,apparent oil/water partition coefficient?logP?and melting point of Rg3 were determined,respectively.The permeation of Rg3 was evaluated by transdermal permeation instrument.The enhancing rate was calculated to investigate the enhanced effect of Rg3 by different permeation enhancers.The Rg3 gel was prepared,whose traits,pH,content,viscosity and stability test were evaluated.The analgesic effect of Rg3 gel was investigated by detecting the acetic acid-induced writhing times and PGE₂ content in mice.ResultsRg3 could significantly reduce the acetic acid-induced writhing times,reduce the time of licking paw in formalin test and increase the threshold of mechanical withdrawal in tumor compression pain model.In tumor compression pain model,Rg3 had an inhibitory effect on glutamate?Glu?levels in the brain and increased the levels of?-aminobutyric acid?GABA?and glycine?Gly?.Asp and Tau content had no significant change.The apparent solubility of Rg3 was56.70?g·mL^-1,the logP was 2.63 and the melting point was 312.2?.The enhancing rate of peppermint oil was 2.38.The quality of the prepared Rg3 gel was in accordance with the requirements.The results of mouse acetic acid writhing test showed that Rg3 gel can significantly reduce the number of writhing in mice and reduce the content of PGE₂ in serum.ConclusionsRg3 had significant analgesic effect and its mechanism might be associated with regulating the balance between EAAs and IAAs in brain.Transdermal permeation of Rg3 fitted the zero-order equation in vitro.Peppermint oil could enhance the permeation amount of Rg3 significantly.The Rg3 gel had analgesic effect after transdermal administration in vivo.It provide a theoretical basis and future research directions in the development of transdermal administration of analgesic agents fields.