Intestinal absorption and metabolism of bush tea major phenolic compounds exhibiting anti-diabetic activity.

Athrixia phylicoides (A. phylicoides), popularly known as ‘bush tea’, is an indigenous aromatic shrub found in mountainous and grassland areas of the northern and eastern parts of Southern Africa. The plant is traditionally used for the treatment of several ailments, including coughing, treating infected wounds, boils, sore throat, hypertension and heart disease. An aqueous extract of A. phylicoides, has been shown to improve glucose uptake in vitro when tested in muscle, liver and fat cells. While an aqueous extract of A. phylicoides has been shown to have bioactivity, there is limited knowledge regarding absorption and bioavailability of phenolic compounds present in A. phylicoides. Aim of the study: The present study aims to identify major phenolic compounds in an aqueous extract of A. phylicoides, and describe their transport characteristics across the Caco-2 monolayer. Methods and materials: HPLC-DAD and LC/MS was used to identify major phenolic compounds within the extract as well as monitor the transport of these compounds across the intestinal barrier. Differentiated Caco-2 cells were used as a model to predict bioavailability and identify metabolite formation, respectively. Specific inhibitors were used to assess efflux characteristics of these compounds. Results: Nine major phenolic compounds of the aqueous extract of A. phylicoides were identified with para-coumaric acid identified for the first time. Three other major phenolic compounds; protocatechuic acid (PCA), caffeic acid (CA) and para-coumaric acid (p-CA), were demonstrated to cross the Caco-2 cell monolayer in significant amounts, with Papp values 4.52, 4.35 and 23.80 (x 106) cm/s, respectively. Conclusion: The present study reports, for the first time, the transport of phenolic compounds from an aqueous extract of A. phylicoides with PCA, CA and p-CA being the major transported compounds having relatively low bioavailability.

Grantor dc:publisher.institution

University of Zululand

Year dc:date.issued

2017

Author dc:creator

• Ntamo, Yonela

Advisors dc:contributor.advisor

• Bowles, S.L
• Kappo, A.P
• Muller, C.J,F
• Malherbe, C.J.

• bush tea --athrixia phylicoides --metabolism --diabetes

Licence

• https://devspace.unizulu.ac.za/bitstreams/7bd5a390-ca26-4cd2-84bd-6059c875ac00/download