12 January - 20 June 2016

Casein micelles as carriers of bioactive chemicals

15 Jan 14

A study published in the Journal of Dairy Science, suggests that casein micelles could be used to carry pharmacologically active chemicals to target sites within the body. Researchers from University of Guelph (Canada) used casein micelles to enclose epigallocatechin gallate (EGCG), the major catechin found in green tea. EGCG has been shown to reduce proliferation of cancerous colon cells.  In this study, the cytotoxicity and proliferation behaviour of HT-29 colon cancer cells when exposed to free EGCG was compared with that of nanoencapsulated EGCG in casein micelles of skim milk. EGCG-casein complexes were able to decrease the proliferation of HT-29 cancer cells, demonstrating that nanoencapsulation need not reduce the bioavailability. Bioavailability is usually defined as the fraction of the bioactive constituents that have been absorbed by the body and can exert their biological actions at specific target tissue sites. The interactions between the bioactive molecules and the food matrix are considered critical factors limiting or enhancing bioavailability.  The authors conclude that their study shows that the binding of EGCG to the casein micelles did not affect the bioefficacy of EGCG and cell uptake at concentrations higher than 0.03 mg of EGCG/mL of skim milk. The EGCG-milk complexes were still able to decrease the proliferation of HT-29 cancer cells, similarly to free EGCG. They stress, however, that the present studies were carried out using fresh EGCG. Mixed systems may ensure better stability of tea catechins with storage and during digestion, ultimately improving their bioefficacy.

RSSL's Functional Ingredients Laboratory can analyse green tea for catechins, including epigallocatechin-gallate (EGCG) and epigallocatechin (EGC). For more information please contact Customer Services on Freephone 0800 243482 or email enquiries@rssl.com

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