title: Modulation of drug efflux by aloe materials: An In Vitro investigation across rat intestinal tissue.
abstract: BACKGROUND
  Clinically, significant herb-drug interactions have been previously documented and can be pharmacodynamic and/or pharmacokinetic in nature. Pharmacokinetic interactions have been attributed to induction or inhibition of either metabolic enzymes or efflux transporters.
  
  
  OBJECTIVE
  The effect of gel and whole leaf materials from 3 different aloe species namely Aloe ferox, Aloe marlothii, and Aloe vera as well as polysaccharides precipitated from the A. vera materials on the bi-directional transport of cimetidine across rat intestinal tissue was investigated.
  
  
  METHODS
  Cimetidine transport studies were performed across excised rat intestinal tissue mounted in Sweetana-Grass diffusion chambers in both the apical-to-basolateral and basolateral-to-apical directions.
  
  
  RESULTS
  While A. vera gel and whole leaf materials did not inhibit the efflux of cimetidine, the polysaccharides precipitated from them did show a reduction of cimetidine efflux. On the other hand, both A. ferox and A. marlothii gel and whole leaf materials exhibited an inhibition effect on cimetidine efflux.
  
  
  CONCLUSIONS
  This study identified a modulation effect of efflux transporters by certain aloe materials. This may cause herb-drug pharmacokinetic interactions when drugs that are substrates for these efflux transporters are taken simultaneously with aloe materials. On the other hand, these aloe materials may be used for drug absorption enhancement for drugs with low bioavailability due to extensive efflux.
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa.
authors.forename: Beneke
authors.initials: B
authors.lastname: Carien
authors.forename: Viljoen
authors.initials: V
authors.lastname: Alvaro
authors.forename: Hamman
authors.initials: H
authors.lastname: Josias
keywords: Aloe ferox; Aloe marlothii; Aloe vera; efflux; herb-drug interaction; in vitro transport