Anti-inflammatory And Antinociceptive Activity And Chemical Constituents Of Dioscorea Septemloba Thunb

In accordance with the International Association for the Study of Pain,pain has been defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage,or described in terms of such damage.The pain appears widely in various kinds of diseases in clinic.Patients with intense and unrelenting pain need effective and potent analgesic agents.So it is very important to use analgesic exactly to control pain effectively.Because it can release the pain of the diseases,improve the life quality,at the same moment give the patients a comfort and extra confidence to fight with the diseases.According to the mechanism of pharmacological effect,analgesic agents are generally divided into opioid analgesics,such as alkaloid morphine,and non-steroidal anti-inflammatory drugs(NSAID),like aspirin.The opioid analgesics have some side effects such as addiction or respiratory depression and the NSAID has side effects to damage gastrointestinal tract.So it is necessary to search for new effective and nontoxic analgesics in plant-derived secondary metabolites from the natural products.Dioscorea septemloba Thunb.,a plant of Dioscorea genus,is widely distributed in the provinces of the southeast in China,snch as Zhejinag,Fujian,Jiangxi,Hunan,Guangdong and Guangxi and were used to treat chronic prostatitis,nonliquefaction of semem,osteoarthritis,osteoporosis,rheumatism and atrophic arthritis.Dioscorea septemloba Thunb.contain many kinds of chemical compounds, including steroidal glycosides,steroidal sapogenins,diarylheptanoids,lignans and etc.It is proved to have antiatheroscleorotic,antiosteoporotic and anti-tumor activities.The ethanol extract from Dioscorea septemloba Thunb.was evaluated on antinociceptive activity in mice using chemical and thermal models of nociception.Given orally,the ethanol extract,the n-butanol fraction and the chloroform fraction produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin or capsaicin injections and on thermal nociception in the tail-flick test and in the hot plate test.Dioscorea septemloba Thunb.was under bioassay-guided isolation,nine compounds were isolated from the ethanol extract of it by using column chromatography of silica gel,Sephadex LH-20,ODS and HPLC.Four compounds were isolated from the chloroform soluble fraction,and the other five compounds were isolated from the n-butanol soluble fraction.Their structures of the eight compounds were elucidated on the basis of chemical and NMR spectral methods as:(1)β-sitosterol;(2)β-carotene;(3) stigmasterol;(5) dioscin;(6) diosgenin;(7) methyl protodioscin;(8) spongioside A;(9) piperitol.