Levels of selected metals in the leaves of Ruta chalepensis L. (Rue) collected from four different areas of Ethiopia

Abstract

The objective of this study was to determine the level of selected metals in the leaves of Ruta chalepensis L. (Rue) cultivated in Ethiopia. Rue leaves samples were randomly collected from four different parts of Ethiopia (Kality and Alem Bank from Addis Ababa Administration, Holeta (Oromia Region) and Worabe (South Nations and Nationalities Peoples Region)). A 0.5 g Rue sample was digested with 3.0 mL of 69.5% HNO₃ and 1.0 mL 70% HClO₄ and the levels of selected metals were determined by flame atomic absorption spectrometry. The validity of the optimized procedure was evaluated by analyzing the digest of the spiked samples with standard solution and the percentage recoveries varied from 92.0 to 102%. The levels of metals determined in mg/kg dry weight were in the ranges Ca (1872–3077), Zn (44.5–64.0), Cu (<DL–10.8), Cr (<DL–3.10) and Cd (<DL–2.87) (where DL is detection limit). Ni and Pb were below the detection limit. ANOVA at p = 0.05 indicated that there is a significant difference in the level of Ca, Cr, Cu and Zn in the samples. The results indicate that the content of the metals did not exceed the permissible amount for medicinal plants set by WHO and FAO.

KEY WORDS: Ruta chalepensis L., Rue, Tena Adam, Metals, Flame atomic absorption spectrometry, Ethiopia

Bull. Chem. Soc. Ethiop. 2018, 32(2), 185-197.

DOI: https://dx.doi.org/10.4314/bcse.v32i2.1