Analysis of the Bioavailable Fluoride Level in Chewable Part of Some Selected Khat Cultivars Commercially Available around Jimma

Abstract

In this study, the levels of fluoride in selected commercial Khat (Catha edulis Forsk) of Jimma Town, Ethiopia have been investigated using fluoride ion selective electrode. Khat samples were collected from different local Khat shops available in the Town. The collected samples were transported to laboratory and prepared for analysis by taking the chewable parts only, i.e., the youngest leaves and tips of the samples were considered for analysis of both the water soluble and the total fluoride contents. Determination of the water-soluble fluoride content of each sample was carried out by soaking the chopped Khat leaves and tips in distilled water and stirred for five minute. Whereas, determination of the total fluoride content was performed by ashing the dried Khat leaves and tips using muffle furnace. For quantitative determination an external calibration curve which was constructed from seven point fluoride concentration levels was used. Recovery studies were conducted to test the suitability of the method used for the determination of fluoride in studied matrix and was found to be in the range of 88-to-112 %. The content of fluoride in fresh unwashed and washed leaves as well as in fresh unwashed and washed tips samples were found ranging from 0.056 - 0.046 µg /g and 0.041 0.049 µg /g as well as 0.037 - 0.045 μg/g and 0.034 – 0.041 μg/g and in dried leaves and tips samples studied were in the range of 3.35 - 5.30 µg/g and 2.66 - 3.87 µg /g, respectively. Furthermore, the obtained level of fluoride was compared with the reported literature values of other area Khat as well as different guidelines. The study findings, revealed the presence of significant difference in the fluoride level between the Khat leaves and Tips as well as between the unwashed and washed fresh samples. Generally, the observed concentrations of both water soluble and total fluoride in the studied Khat samples were below the WHO guideline for human daily safe intake of fluoride.