The effect of two African mineral dyes Yombo tumtum (YT) and Yombo fita (YF) on the activity of alkaline phosphatase (ALP) in the skin and serum of albino rats was investigated. The chemical analyses of the dyes were first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of each dye were prepared using hydrogen peroxide as solvent. A total of 70 albino rats (
Rattus norvegicus
) were used for the study. The rats were grouped into 14 of 5 rats and were maintained on commercial feed for a period of 30 days, during which the experiment lasted. Group I served as the first control and the animals had distilled water applied on their heads. Group 2 which served as the second control contained rats on whose heads were applied the dissolving solvent i.e. hydrogen peroxide. Rats in group 3 to 8 had the various concentrations of YT (black) dye applied on their heads, while those in groups 9 to 14 had the various prepared concentrations of YF (white) dye applied on their heads. At the end of the experiment, blood samples were collected and portion of the head skin where the dyes were applied was cut. The activity of ALP was thereafter determined in the serum and skin of the experimental animals. The results revealed a significant decrease (p<0.05) in the activity of ALP as the concentration of the dye increased in both the serum and skin
