title: Efficacy and safety of "Yahom" as a traditional Thai herbal therapy: A systematic review.
abstract: BACKGROUND
  Yahom is a traditional Thai medicine used to treat syncope and abdominal discomfort.
  
  
  OBJECTIVE
  This study aimed to systematically review all available evidence which purports to support these claims.
  
  
  METHODS
  The systematic review accorded with the Cochrane Collaboration framework and PRISMA reporting. Databases including MEDLINE, Excerpta Medica Database (EMBASE), Cochrane library database, and Google Scholar were searched by keywords, Yahom and Ya-hom. Pharmacological and toxicity data from non-animal and animal studies were included.
  
  
  RESULTS
  Twenty-four articles: 2 on in vitro cell lines or bacteria, 3 in vitro cell-free, 5 in vitro animal, 13 in vivo and 1 human mainly reported (A) Cardiovascular effects (i) transient hypotension (0.2-0.8g/kg, intravenous injection (i.v.)), increased cerebral blood flow (2g/kg, single oral) and vascular dilatation/relaxation (ii) elevated blood pressure (BP) (0.2-0.8g/kg, i.v. or 2-4g/kg oral) and vasocontraction. Single Yahom doses (3g) given to healthy volunteers had no effect on cutaneous blood flow, ECG or systolic BP although marginally increased diastolic BP was claimed. (B) Yahom (2-4g/kg) completely inhibited gastric acid secretion evoked by gastric secretagogues. (C) Toxicity: Chronic oral doses of selected Yahoms to rodents (0.001-1g/kg) supports its status as generally regarded as safe.
  
  
  CONCLUSIONS
  Most studies supported declared objectives relating to perceived Yahom actions, but lacked background demonstrating clinical efficacy, and mechanistic data that would validate conclusions. Our study suggests that research into traditional medicinal herbs needs underpinning by appropriate clinical interventions and pharmacovigilance, thereby optimising efficacy and minimizing toxicity by combining traditional wisdom and modern testing.
authors.affiliation: Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Krongkarn
authors.initials: K
authors.lastname: Chootip
authors.affiliation: Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand; School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, Malaysia; Center of Pharmaceutical Outcomes Research, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand; School of Pharmacy, University of Wisconsin, Madison, WI, USA; School of Population Health, University of Queensland, Brisbane, Australia; Center for Environmental Health & Toxicology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Nathorn
authors.initials: N
authors.lastname: Chaiyakunapruk
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Noppamas
authors.initials: N
authors.lastname: Soonthornchareonnon
authors.affiliation: Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand; Center for Environmental Health & Toxicology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: C Norman
authors.initials: CN
authors.lastname: Scholfield
authors.affiliation: Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand. Electronic address: anjanaf@nu.ac.th.
authors.forename: Anjana
authors.initials: A
authors.lastname: Fuangchan
mesh_terms: D000818:Animals; D006801:Humans; D008519:Medicine, Traditional; D008517:Phytotherapy; D010936:Plant Extracts / Q000627:therapeutic use*; D013785:Thailand; D016896:Treatment Outcome
chemical_list: D010936:Plant Extracts; C000621167:yahom
keywords: Folk medicines; Herbal medicines; Systematic review; Thai traditional herbs; Ya-hom; Yahom