Intestinal drug transport enhancement by Aloe vera

Many drugs are poorly absorbed from the gastrointestinal tract when administered by the oral route. One approach to overcome the restriction of the physical barrier to drug absorption is the co-administration of absorption enhancing agents [1]. In this study the effect of Aloe vera (L.) Burm. f. (Aloe barbadensis Miller) gel and whole leaf extract on the permeability of intestinal epithelial cell monolayers (Caco-2) was determined. Solutions of gel and the whole leaf extract were applied to the cell monolayers and the transepithelial electrical resistance was monitored, which was continued after removal of the test solutions to measure reversibility of the effect. The transport of model compounds in the presence and absence of the A. vera gel and whole leaf extract solutions was also investigated. Both the A. vera gel and whole leaf extract were able to significantly reduce the transepithelial electrical resistance of the Caco-2 cell monolayers at concentrations above 0.5% w/v, which was fully reversible. The A. vera gel and whole leaf extract solutions significantly enhanced the transport of model compounds across the Caco-2 cell monolayers compared with the control. The results suggest that these plant products have a high potential to be used as absorption enhancers in novel dosage forms for drugs with poor bioavailabilities when administered orally. On the other hand, an uncontrolled increase in the bioavailability of drugs that are taken simultaneously with A. vera gel and whole leaf extract products may result in adverse effects.

References: 1. Whitehead et al. (2008). Pharm Res, 25:1782–1788.