title: Radix astragali and orthostatic response: a double-masked crossover study.
abstract: OBJECTIVE
  Recent results from animal experiments have shown that radix astragali (RA), a traditional Chinese herbal tonic, alleviates muscle atrophy under simulated weightlessness conditions, rendering RA a candidate for human use as a countermeasure against muscular atrophy. Possible cardiovascular side effects have not yet been investigated. We analyzed the effects of RA on the orthostatic stability of healthy men.
  
  
  METHODS
  There were 10 test subjects who were assigned to a double-blinded, randomized crossover design using RA or placebo (PL) for 14 d each, respectively. Test runs were separated by a 14-d 'washout' interval. At the beginning and the end of every 14-d test run, graded orthostatic stress (GOS) consisting of head-up tilt (HUT) combined with lower body negative pressure (LBNP) was used to achieve a presyncopal endpoint. Orthostatic effects on cardiac and vascular function were continuously monitored.
  
  
  RESULTS
  There were no significant differences between the RA vs. PL groups: mean arterial blood pressure dropped by 13 vs. 17%, pulse pressure 46 vs. 35%, heart rate increased 108 vs. 117%, and stroke volume index decreased 54 vs. 49% from supine control to presyncope. Neither did RA influence standing time compared to PL (18 +/- 7 vs. 17 +/- 6 min), nor did progression from the first to the fourth trial (15 +/- 6 to 18 +/- 7 min).
  
  
  CONCLUSIONS
  RA does not influence resting cardiovascular variables and orthostatic capacity in humans. It can be expected that human studies of RA's musculo-skeletal countermeasure potential will not be compromised by any cardiovascular side effects at the dosage employed in this study.
authors.affiliation: Department of Biology, College of Life Sciences, Northwest University, Xi'an, China.
authors.forename: Yunfang
authors.initials: Y
authors.lastname: Gao
authors.forename: Nandu
authors.initials: N
authors.lastname: Goswami
authors.forename: Erik
authors.initials: E
authors.lastname: Grasser
authors.forename: Andreas
authors.initials: A
authors.lastname: Rössler
authors.forename: Erich
authors.initials: E
authors.lastname: Stöger
authors.forename: Günther
authors.initials: G
authors.lastname: Schwaberger
authors.forename: Helmut G
authors.initials: HG
authors.lastname: Hinghofer-Szalkay
mesh_terms: D027885:Astragalus propinquus; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007024:Hypotension, Orthostatic; D008297:Male; D009133:Muscular Atrophy / Q000188:drug therapy; D009465:Neuromuscular Agents / Q000494:pharmacology*; D013575:Syncope / Q000503:physiopathology; D018667:Tilt-Table Test; D014893:Weightlessness / Q000009:adverse effects*; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation / Q000379:methods
chemical_list: D004365:Drugs, Chinese Herbal; D009465:Neuromuscular Agents; C027492:Huang Qi