Thirteen-week oral toxicity study of carotenoid pigment from Rhodotorula glutinis DFR-PDY in rats.

Carotenoids from some of the coloured yeasts like Rhodotorula, Phaffia rhodozyma have attracted commercial interest as a natural pigment for foods. Red yeast isolated from contaminated Potato dextrose agar plate (PDA), designated as Rhodotorula glutinis DFR-PDY has been found to produce carotenoids. In the present study toxicological evaluation of carotenoid pigment has been reported. Experiment was conducted on 3 groups of albino rats. One group with vehicle control (palm oil) and 2 groups with two different doses of red yeast pigment (lower and higher dose) were fed to rats (both male and female) by gavages for 13 weeks. Gain in body weight of rats and food consumption were monitored at regular intervals. Hematological studies revealed that there is no much difference in erythrocytes, packed cell volume, Mean corpuscular volume (MCV), Mean corpuscular haemoglobin concentration (MCHC), platelets and differential counts. Total leucocyte count (TLC) is less in case of higher dose group than the lower and control groups. Whereas, hemoglobin is more in case of higher dose than the lower dose group and least in control group. Even clinico-chemical parameters and urine analysis of vehicle control group and pigment fed rats revealed that there were no major differences between them as well as between two different genders of rats and also interaction between different doses and the genders. Histopathology of these experimental animals revealed that there are no major histological changes found between the groups. It may be concluded that the whole pigment extract from R. glutinis DFR-PDY may be used safely in food preparations as food colourant with an added benefit of antioxidant activity.