Some beneficial and toxic constituents of selected herbal antihyperglycemic products marketed in Kaduna State, Nigeria

Abstract

Herbal medicines are used worldwide to maintain health and to prevent or cure diseases. The presence of some of these herbal medicines in the market that do not meet or fulfill standards set by the standard regulatory bodies in Nigeria is a matter of concern. This study was aimed at determining the potential benefits and/or safety of selected herbal antihyperglycemic products marketed in Kaduna, Nigeria. A total of twenty samples were selected randomly and assigned codes (S1-S20). Preliminary phytochemical tests were carried out using standard procedures. The samples were also digested with HNO₃:HClO₄ (2:1) mixture, then analyzed for essential trace metals (Cr, Mn, Fe and Zn) and toxic metals (Pb and Cd) using Atomic Absorption Spectrophotometer. Results obtained revealed the presence of alkaloids, flavonoids, cardiac glycosides, carbohydrates, saponins, terpenoids and tannins in the following amounts, 20, 75, 80, 85, 90, 60 and 65 % respectively, in the samples analyzed. The essential trace metals Cr, Mn Fe and Zn were detected in all the samples at permissible concentration ranges of 0.03 - 0.98, 0.01 - 4.00, 16.36 - 331.45 and 0.34 - 36.64 µg/g respectively. The toxic metal Pb was detected at concentration range of 0.35 - 14.23 µg/g in 80 % of the samples with 20 % of them being above the permissible limit. On the other hand, Cd was detected in only one sample at a concentration (2.90 µg/g) above the permissible limit. The study concluded that these herbal samples contained varying concentrations of phytochemicals and essential metals which may play a vital role in controlling blood sugar levels. However, some of the samples may not be safe for consumption due to their contamination with toxic metals.