Toxicological safety evaluation of a novel highly bioavailable turmeric extract formulation.

Abstract

Turmeric (Curcuma longa L.) extracts have a long history of use worldwide, but a major limitation of these extracts is their extremely low oral bioavailability, caused by low absorption, rapid metabolism and rapid excretion following ingestion. Thus, a new highly bioavailable turmeric extract formulation (comprising turmeric extract, acacia gum, sunflower oil and quillaia extract) has been developed and is intended for use as a food ingredient. Safety of this novel extract was evaluated using the standard Tier 1 battery of in vitro genotoxicity tests (bacterial reverse mutation test and an in vitro mammalian cell micronucleus test) followed by repeated-dose 28- and 90-day oral toxicity studies in rats. In the 90-day study, male and female Sprague-Dawley rats were dosed once daily, by oral gavage, either with the vehicle or the test item at 500, 1500 or 3000mg/kg body weight/day. Clinical examinations were conducted regularly, and body weights and food consumption were recorded weekly throughout the study. At the end of the study, blood samples were analyzed for clinical pathology parameters, before a macroscopic necropsy was conducted and a full list of tissues were examined histopathologically. There was no evidence of genotoxicity in vitro. No test item-related adverse effects were observed in the 28- or 90-day studies; therefore, 3000mg/kg body weight/day (the maximum feasible dose and highest dose tested in rats) was established as the no-observed-adverse-effect level.