title: Cardioprotective effect of total saponins from three medicinal species of Dioscorea against isoprenaline-induced myocardial ischemia.
abstract: BACKGROUND
  As folk medicines used in China since 1950s, Dioscorea nipponica Makino (DN), D. panthaica Prain et Burkill (DP), and D. zingiberensis C.H. Wright (DZ) are regarded as having more or less the same traditional therapeutic actions, such as activating blood, relieving pain, and dispersing swelling. It is noteworthy that, of the 49 species of the genus Dioscorea distributed in China, based on such traditional efficacies, only these three have been further developed as effective single-herb medicines for treating cardiovascular diseases by the modern pharmaceutical industry. In our previous study, it was found that the chemical compositions of DN and DP were similar, and both were distinct from that of DZ. Hence, whether their different chemical profiles support their anti-IHD (ischemic heart disease) activity in common still needs to be answered. So far it is still unknown whether the efficacies of these three herbs act via similar mechanism and whether they possess comparable therapeutic efficacy for experimental myocardial ischemia (MI).
  
  
  OBJECTIVE
  The present study aimed to further investigate the underlying mechanisms with respect to antioxidative stress activity by which these Dioscorea spp. attenuate MI, and to compare the therapeutic effect of total saponins from these three species on myocardial antioxidant levels and myocardial histology.
  
  
  METHODS
  The serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), total superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPx), the total antioxidant capacity (T-AOC), and malondialdehyde (MDA), as well as myocardial histology, were compared among rat groups administered with total saponins (TS) of DN, DP or DZ (abbreviated as DNTS, DPTS and DZTS, respectively). The rats experienced myocardial ischemia induced by isoprenaline (ISO) injection; the test solutions (DNTS, DPTS, DZTS) were administered either after the ISO injection, or both before and after.
  
  
  RESULTS
  Compared with the model group (ISO injection only), TS groups exhibited significantly reduced activities of CK, LDH and AST, lowered level of MDA, and increased activities of SOD, CAT, GPx and T-AOC; heart tissues from TS groups revealed less severe histological damage. The cardioprotective efficacy of these three Dioscorea TS for rat MI was closely comparable based on the above observations.
  
  
  CONCLUSIONS
  The findings of the present study provide evidence that the anti-MI effect of DNTS, DPTS and DZTS can be attributed to the increase of myocardial antioxidant levels and decrease of lipid peroxidation formation, and the closely comparable results observed from these three Dioscorea saponins thereby explains the similarity in their clinical efficacy as anti-MI drugs.
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Yi-Na
authors.initials: YN
authors.lastname: Tang
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Xi-Cheng
authors.initials: XC
authors.lastname: He
authors.affiliation: Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
authors.forename: Min
authors.initials: M
authors.lastname: Ye
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Chemistry, Lanzhou University, Lanzhou 730000, China.
authors.forename: Hong-Li
authors.initials: HL
authors.lastname: Chen
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Peng
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region.
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Zhao
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region. Electronic address: yitao@hkbu.edu.hk.
authors.forename: Tao
authors.initials: T
authors.lastname: Yi
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region. Electronic address: hbchen@hkbu.edu.hk.
authors.forename: Hu-Biao
authors.initials: HB
authors.lastname: Chen
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002316:Cardiotonic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002374:Catalase / Q000378:metabolism; D003402:Creatine Kinase / Q000097:blood; D027742:Dioscorea; D005979:Glutathione Peroxidase / Q000378:metabolism; D007545:Isoproterenol; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000494:pharmacology / Q000627:therapeutic use*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002316:Cardiotonic Agents; D012503:Saponins; D008315:Malondialdehyde; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D001219:Aspartate Aminotransferases; D003402:Creatine Kinase; D007545:Isoproterenol
keywords: Antioxidative activity; D. Panthaica; D. Zingiberensis; Dioscorea nipponica; Myocardial ischemia; Total saponins