Experimental Study On Pharmacodynamics And Acute Toxicity Of Three Grass Extract

Objective:To evaluate on anti-inflammatory, analgesic and antipyretic, immune, expectorant and antitussive effects of three grass extract scientifically and also to evaluate on the safety of three grass extract scientifically through research on pharmacodynamic effects and acute toxicity of the extract of effective parts of three grass extract. To preliminarily study on anti-inflammatory mechanism of three grass extract through the influence of three grass extract medicated serum on LPS stimulated RAW264.7macrophage, for providing scientific basis of further developing three grass extract.Methods:1. Research on pharmacodynamic effects of three grass extract:(1) anti-inflammatory action:The experiment of ear swelling induced by xylene in mice, the experiment of influencing on abdominal capillary permeability in mice, toes swelling caused by carrageenan in rats and the experiment of resisting on formation of cotton ball granuloma in rats were used to study the anti-inflammatory effect of three grass extract.(2) antipyretic action:The experiment of fever in rats induced by bread yeast and fever in rabbits induced by endotoxin were adopted to study the antipyretic effect of three grass extract.(3) analgesic action:The pain models were established by hot plate and acetic acid in mice for studying the analgesic effect of three grass extract.(4) immune action:The experiment of phagocytic function on the reticuloendothelial system (RES) in mice was used to study the immune effect of three grass extract.(5) expectorant and antitussive action:The experiment of excretion of phenol red in the airway of mice, and the cough model induced by SO2in mice were adopted to study the expectorant and antitussive effects of three grass extract.2. Research on acute toxicity of three grass extract:To determine median lethal dose (LD50) of three grass extract.3. Preliminary study on anti-inflammatory mechanism of three grass extract--the influence of three grass extract medicated serum on LPS stimulated RAW264.7macrophage:(1) To determine growth curve of RAW264.7macrophage by MTT.(2) To test the influence of three grass extract medicated serum on RAW264.7macrophage proliferation by MTT.(3) To test the influence of three grass extract medicated serum on LPS stimulated RAW264.7macrophage proliferation by MTT.(4) To investigate the influence of three grass extract medicated serum on LTB4production and IL-1β, IL-6, TNF-α production by ELISA.Results:1.(1) anti-inflammatory action:Three grass extract significantly inhibited xylene-induced ear swelling and peritoneal capillary permeability in mice. Also it obviously inhibited toes swelling induced by carrageenan and cotton pallet granuloma in rats. So three grass extract owed a prominent anti-inflammatory effect.(2) antipyretic action:Three grass extract could remove fever in rats and rabbits infected by20%bread yeast and endotoxin. So three grass extract had a good antipyretic effect.(3) analgesic action:Three grass extract could increase the threshold value of pain induced by hot plate and decrease times of writhing reaction induced by0.5%acetic acid in mice, it had a obvious analgesic effect.(4) immune action:Three grass extract could increase the phagocytosis function of reticuloendothelial system (RES) on India ink in mice.(5) expectorant and antitussive action:Three grass extract could increase the excretion of phenol red in the airway of mice, also it prolonged the latent period of cough induced by SO2in mice and decrease their cough times. So three grass extract had apparent expectorant and antitussive effects.2. Research on acute toxicity of three grass extract:The median lethal dose (LD50) of mice was185.8541g/kg, it was the human clinical dosage (0.5g/kg)317times.3. Preliminary study on anti-inflammatory mechanism of three grass extract--the influence of three grass extract medicated serum on LPS stimulated RAW264.7macrophage:(1) to determine growth curve of RAW264.7macrophage by MTT:RAW264.7macrophage grew slowly from first day to fifth day, and its growth trend was stable, then it started rapid growth from the fifth day,and it reached the peak in the seventh day.(2) to test the influence of three grass extract medicated serum on RAW264.7macrophage proliferation by MTT:Three grass extract medicated serum could promote RAW264.7macrophage proliferative activity, and it didn’t have the cell toxicity.(3) to test the influence of three grass extract medicated serum on LPS stimulated RAW264.7macrophage proliferation by MTT:Three grass extract medicated serum had growth inhibition by LPS stimulation in RAW264.7macrophage, and inhibited the proliferation of RAW264.7macrophage.(4) to investigate the influence of three grass extract medicated serum on LTB4production and IL-1β, IL-6, TNF-α production by ELISA:RAW264.7macrophage were stimulated by LPS, then promoted production of LTB4, but three grass extract medicated serum could inhibit the production of LTB4. RAW264.7macrophage were stimulated by LPS, then promoted production of IL-1β and IL-6, and production of TNF-α, but three grass extract medicated serum could inhibit the production of IL-1β and IL-6, and production of TNF-αConclusion:Three grass extract has anti-inflammatory, analgesic and antipyretic, immune, expectorant and antitussive effects. Conclusion on acute toxicity of three grass extract is that the median lethal dose (LD50) of mice was185.8541g/kg, it was the human clinical dosage (0.5g/kg)317times. The acute toxicity of three grass extract is so little that it is safe to take in the conventional dose. Three grass extract medicated serum could inhibit the production of LTB4. Also three grass extract medicated serum could inhibit the production of IL-β and IL-6, and production of TNF-α. Preliminary results show that three grass may exert anti-inflammatory effect through reducing the secretion of inflammatory mediators about LTB4, IL-1β,IL-6,and TNF-α.