Evaluation of preclinical safety of combined extracts of Taraxacum officinale, Zingiber officinale AND Vernonia amygdalina

Abstract

The use of herbal medicines for treatment of different disease has been in existence for a long time in human history. Although herbal medicines are considered safe by the public, some herbal medicines have known toxicity level and effects on various organs of the body while other medicinal plants have no published data about their toxicity, adverse reactions, among other contraindications and side-effects. Evaluation of preclinical safety of combined extracts containing Taraxacum officinale roots, Vernonia amygdalina leaves, and Zingiber officinale rhizomes were required to establish the toxicological profiles of new herbal formulations from the combined extracts of these plants before administration to humans. The general objective of this study was to assess the preclinical safety profile of the combined extracts containing Taraxacum officinale roots, Zingiber officinale rhizomes, and Vernonia amygdalina leaves. This was an experimental research study in which the authenticated Vernonia amygdalina-leaves, Zingiber officinale-rhizomes, and Taraxacum officinale-roots each were pulverized into a fine powder and later independently extracted by cold maceration for three days using 85% ethanolic solution. The extracts were used for phytochemical test, combined in the ratio of 1:1:1 for evaluation of toxicity. Phytochemical test was carried out by adopting standards procedures. LD50 was determined by adopting and modifying the Lorke’s method as modified by Imafidon and co-workers (exempting first phase and use of 10 rats in second phase). Subacute oral toxicity study was conducted by adopting and modifying the OECD guideline No. 407 for the repeated dose by using 6 rats per group for 30days at the doses (750, 1500, and 5000) mg/kg/body weight. Phytochemical analysis of individual plant extracts revealed highest concentration of flavonoids. The acute oral toxicity of the combined extracts was high with an LD50 of 6708.2 mg/kg body weight. The subacute toxicity study showed no histopathological damage to liver and kidneys. Flavonoids present in highest concentration in all the extracts and is known to have strong antiinflammation and antioxidants properties which makes the new formulation from these extracts a good candidate for treating diseases with inflammatory modes of actions. The acute and sub-acute toxicity results of the combined crude ethanolic extracts of Taraxacum officinale, Vernonia amygdalina, and Zingiber officinale indicates a wide safety range with no toxicity on the liver and kidney. This shows that, any formulated herbal drug from combined extracts of Taraxacum officinale, Vernonia amygdalina, and Zingiber officinale will have no safety concerns over long term administration.