Anti-inflammatory Effects In Vitro And Anti-bacterial Effects In Vivo Of Aqueous Extract Of Urena Lobata L

Objective: To study the anti-inflammatory effects in vitro andanti-bacterial effects in vivo of aqueous extract of urena lobata L..Methods:1.The acute toxicity was tested in mice by intragastricadministration.2. The experiment animals were respectively divided into control group,positive control group (dexamethasone10mg·kg-1) and three dose groups (10g·kg-1,20g·kg-1,40g·kg-1) of aqueous extract of urena lobata L., ig. Modelsof xylene-induced ear edema, carrageenan-induced paw edema and cottonpellet-induced granuloma tissue growth in mice were utilized to observeeffects of aqueous extract of urena lobata L. on acute and chronicinflammation.3. The experiment animals were respectively divided into control group, model group, positive control group (dexamethasone10mg/kg) and threedose groups (10g·kg-1,20g·kg-1,40g·kg-1) of aqueous extract of urenalobata L., ig. Models of glacial acetic acid-induced peritoneal inflammationand carrageenan-induced acute air-pouch synovitis in mice were performed.And the content of prostaglandin E2(PGE2) in abdominal exudate andprotein, nitric oxide (NO), PGE2, malondialdehyde (MDA) and superoxidedismutase (SOD) activity in exudate of acute air-pouch synovitis mousewere detected to explore effects of aqueous extract of urena lobata L. oninflammatory mediators, oxygen free radicals, etc.4. The minimum inhibitory concentrations (MIC) of aqueous extract ofurena lobata L. were performed to study antibacterial effect in vitro by tubedouble dilution method.5. The MIC of aqueous extract of urena lobata L. combined withantibacterial agents against S. aureus, E. faecalis, E. coli and P. aeruginosa invitro were respectively tested by checkerboard method and then thefractional inhibitory concentration (FIC) was calculated to investigate thecombined antibacterial effect.Results:1. After intragastric administration, none of mouse died andthe MLD of aqueous extract of urena lobata L. was240g·kg-1.2. High, medium and low dosage of aqueous extract of urena lobata L.could reduce xylene-induced ear edema (P<0.05, P<0.01), and the inhibitionrates were respectively39.12%,24.09%,23.06%; High and medium dosegroups inhibited carrageenan-induced paw edema (P<0.05, P<0.01) andsignificantly reduced the formation of granulomatous tissue (P<0.01): toe swelling inhibition rates were40.23%,21.76%, granuloma inhibition rateswere30.59%,19.77%respectively.3. Compared with the model group, high and medium dose groupscould decrease volume of exudate, recover SOD activity (P<0.01, P<0.05) inexudate of acute air-pouch synovitis and significantly reduce PGE2levels(P<0.01) both in abdominal exudate and exudate of acute air-pouch synovitis;All groups could reduce the content of protein (P<0.05) and MDA (P<0.01,P <0.05). Furthermore, high dose group could inhibit the production of NO(P<0.05).4. The aqueous extract of urena lobata L. had certain inhibitory effectagainst S. aureus, E.faecalis, E.coli, P. aeruginosa, E.cloacae, K. Pneumoniaeand E.litharge. The MIC were respectively0.25g·ml-1,0.125g·ml-1,0.5g·ml-1,0.5g·ml-1,0.25g·ml-1,0.25g·ml-1,0.25g·ml-1. Whereas, noantimicrobial activity was found against MDR acinetobacter-baumannii,ESBL-producing-k.pneumoniae and ESBL-producing-e.coli.5. The synergism (FIC=0.19and0.28, respectively) was shown in thecombination of aqueous extract of urena lobata L. and azithromycin orlevofloxacin against S. aureus, and the additive effect (FIC=0.75) orindifferent effect (FIC=2.0) was found in the combination of urena lobata L.and cefazolin sodium or clindamycin, respectively. The combination ofaqueous extract of urena lobata L. with ampicillin sodium or levofloxacinagainst E. faecalis both showed synergism (FIC=0.50and0.27, respectively).The combination of aqueous extract of urena lobata L. with sodiumpiperacillin tazobactam sodium or amikacin or levofloxacin against E.coli all indicated additive effect (FIC=0.53,0.75and0.75, respectively), and againstP. aeruginosa all showed indifferent effect (FIC=2,1.84and2, respectively).Conclusion:1. The aqueous extract of urena lobata L. has nosignificant toxicity.2. The aqueous extract of urena lobata L. has certain inhibitory effecton acute and chronic inflammation, and its mechanism may be associatedwith scavenging oxygen free radicals, inhibiting lipid peroxidation, reducingthe synthesis and release of NO and PGE2.3. The aqueous extract of urena lobata L. show different degrees ofantibacterial effects on S. aureus, E. faecalis, E. coli, P. aeruginosa, E.cloacae, K. Pneumoniae and E. litharge. The MIC of combination against S.aureus or E. faecalis or E. coli was decreased significiantly, which showsdifferent degrees of enhanced effects.