Preliminary Comparative Phytochemical, Elemental and Acute Toxicity Analyses of Selected Conventional and Herbal Medicines

Abstract

Use of herbal medicines for treatment, management and prevention of different diseases is as old as man. In the last few decades, there has been an upsurge in the use of complementary and alternative medicines, which includes herbal medicines, either alone, or combined with conventional medicines. Furthermore, some 75–80% of persons living in the less developed countries depend on traditional medicine (mostly herbal medicines), for their healthcare needs. Despite the general belief worldwide that herbal medicines are safe, with no toxic effects because they are of natural origin, numerous reports such as cases of liver and neuro toxicities from using Cimicifuga racemosa and Valeriana officinalis solely, confirm that this belief is not necessarily valid. The aim of this study was to determine some toxicological parameters of selected conventional and herbal medicines with special reference to antimalarials. The conventional antimalarials studied were artesunate (AS), artemeter/lumefantrine (AL) and pyrimethamine/sulphadoxine (SP) while the herbal medicines were the antimalarial Herb 25(R) (25), herbal blood purifier (BP) and herbal orange rind (OR). In addition to qualitative phytochemical analyses, acute toxicity was determined in 7‐day old cockerels, following oral (p.o.) and intraperitoneal (i.p.) administration, using Lorke’s method. For metal analyses, samples were wet digested with nitric and perchloric acids, and the concentrations of Cadmium (Cd), Calcium (Ca), Chromium (Cr), Cobalt (Co), Copper (Cu), Nickel (Ni), Iron (Fe), Magnesium (Mg), Manganese (Mn) and Zinc (Zn) were determined using flame atomic absorption spectrophotometric (AAS) method. Conventional medicines studied contained no phytochemicals (as expected), while the herbal medicines were found to contain bioactive constituents such as anthracenes, cardiac glycosides, flavonoids, steroids, tannins and triterpenes ‐ which were possibly responsible for the latter’s therapeutic effects and toxicity. The p.o./i.p. LD50 values in mg/kg were: AT‐(470/3,807), AL‐(288/3,807), SP‐(1,264/>5,000), 25‐ (141/2,154), BP‐(141/1,264) and OR‐(774/>5,000). Thus, both conventional and herbal medicines had similar LD50 values although those of herbal medicines tended to be lower, implying higher toxicity. Conventional and herbal medicines contained medicinal elements, namely: Ca, Fe and Zn. Nutritional elements present were Cu, Mg and Mn, although Cu could also be toxic if levels are sufficiently high. Levels of Cd, one of the toxic metals found to be present in nearly all the samples were <0.009 ppm which was below the standard limits set by regulatory bodies like FDA (<0.08 ppm), Health Canada (<3 ppm) and WHO (<0.3 ppm). Levels of another toxic metal, Cr, present in concentration range of 0.56–1.35 ppm, were also below WHO limit of 15 ppm. Co and Ni were below detection levels in all samples ‐ conventional and herbal. Based on the toxicological parameters examined, the herbal medicines were likely to be slightly more toxic compared to the conventional medicines; debunking the widely‐held view that, herbal medicines are always safer than conventional medicines.