Planta Med 2011; 77 - SL33
DOI: 10.1055/s-0031-1282156

Pharmacokinetic interactions between botanicals and drugs: in vitro investigations

J Hamman 1, A Viljoen 2
  • 1Unit for Drug Research and Development, Faculty of Health Sciences, North-West University, Potchefstroom campus, Potchefstroom, 2520, South Africa
  • 2Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001; South Africa

Herb-drug pharmacokinetic interactions include interferences of plant constituents with drug bioavailability by means of altered absorption, metabolism, distribution and/or elimination [1]. Although in vitro pharmacokinetic interactions are not always clinically significant in the in vivo situation [2], it may in many cases indicate potential important interactions that can influence the bioavailability of co-administered drugs. This work reports on the effects of extracts from different botanicals such as whole leaf extracts and gels (Aloe vera, Aloe ferox) [3], corms (Hypoxis hemerocallidea), aerial parts (Sutherlandia frutescens, Aspalathus linearis) [4], fruit (Sclerocarya birrea, Psidium guajava, Dovyalis caffra, Prunus persica, Fragaria ananassa, Prunus domestica), and vegetables tubers (Daucus carota, Beta vulgaris) on in vitro drug transport as well as transport of phytoconstituents in crude extracts in comparison to purified compounds (Hoodia gordonii, Sceletium tortuosum) [5]. The mechanisms of drug transport alteration was determined for some of the botanicals by means of either measuring transport in two directions (to indicate efflux inhibition/induction) or by measuring the transepithelial electrical resistance (to indicate opening of tight junctions). The results showed that some of the plant extracts increased drug transport in the absorptive direction by decreasing drug efflux transporters, while others induced the efflux transporters. Some plant materials showed the ability to enhance drug transport by opening tight-junctions and thereby allowing paracellular drug transport. These types of pharmacokinetic interactions can lead to potentially significant clinical side-effects, but on the other hand they may be employed in a controlled way to enhance absorption of poorly absorbable drugs.

Keywords: In vitro transport, herb-drug pharmacokinetic interactions, drug absorption enhancement, Caco-2, intestinal mucosa, buccal mucosa

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4. Brown L et al. (2008)J Ethnopharmacol 119: 588–592.

5. Vermaak I et al. (2011) Phytomed doi:10.1016/j.phymed.2011.01.017.