title: Seasonal variation in uterotonic activity of Rhoicissus tridentata extracts.
abstract: BACKGROUND
  Rhoicissus tridentata lignotubers are widely used in southern African traditional pregnancy-related remedies.
  
  
  OBJECTIVE
  To determine the seasonal variation in contractile activity of extracts from different parts of the plant.
  
  
  METHODS
  Isolated rat uterus tissue was used to compare the contractile activity of crude aqueous extracts of R. tridentata made from plant material harvested every 3 months over a period of 2 years.
  
  
  CONCLUSIONS
  The activity of the plant extracts from plants harvested in summer and autumn were 4-5-fold higher than extracts from plants harvested in winter or spring. The tubers stimulated the greatest degree of contractions, followed by the stems, roots and leaves. These results highlight the need to standardise the timing of harvesting R. tridentata.
authors.affiliation: Department of Experimental and Clinical Pharmacology, University of the Witwatersrand, Johannesburg.
authors.forename: L C
authors.initials: LC
authors.lastname: Katsoulis
authors.forename: D J H
authors.initials: DJ
authors.lastname: Veale
authors.forename: I
authors.initials: I
authors.lastname: Havlik
mesh_terms: D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D016488:Medicine, African Traditional; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots; D051381:Rats; D017207:Rats, Sprague-Dawley; D012621:Seasons; D013019:South Africa; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D010936:Plant Extracts