Implementation of the Three Rs in the Human Hazard Assessment of Brazilian Medicinal Plants: An Evaluation of the Cytotoxic and Genotoxic Potentials of Dipteryx alata Vogel

Abstract

In Brazil, medicinal plants are widely used by the indigenous people, which leads to a constant requirement for toxicity tests to be performed on the plant extracts. Although the current Brazilian Directive 90/2004 on the preclinical toxicity testing of phytotherapeutics recommends only in vivo tests, some Brazilian researchers would like to change this situation by implementing the Three Rs in the toxicological testing of medicinal plants. The present study evaluated the cytotoxic and genotoxic potentials of bark extracts from Dipteryx alata Vogel, a medicinal plant of the Brazilian cerrado, by using CHO-K1 (Chinese hamster ovary) cells. An IC50 value was obtained, which corresponded to 0.16mg/ml of plant extract, and from this the equivalent LD50 was determined as 705mg/kg. In order to determine the genotoxic potential of the sample, the frequency of micronucleus formation was assessed. CHO-K1 cells were exposed, during targeted mitosis, to different concentrations of plant extract and cytochalasin B, in the presence and absence of an appropriate metabolic activation system (an S9 mix). The results obtained indicated that it might be possible to implement the Three Rs in assessing the potential human hazard of medicinal plants. The publication of such data can increase awareness of the Three Rs by showing how to optimise the management of animal use, if in vivo toxicological experiments are required.

Assessment of Cytotoxicity, Fetotoxicity, and Teratogenicity ofPlathymenia reticulataBenth Barks Aqueous Extract

“…Nowadays, most of the toxicological studies involving new drugs combine in vivo and in vitro assays in order to increase safety (i.e., in the case of a further approval for clinical use). For example, the evaluation of the development and safety of medicinal products require the estimation of IC50 values [17]. In our experimental conditions, together with the IC50 values in CHO-K1 cells, it was calculated the LD50 as 915 mg/kg.…”

“…In this assay, the inhibitory concentration that kills 50% of the cells (IC 50), was (0.331 mg mL −1 ), as describe by Della Torre et al [15]. Applying the formula: log [LD50 (mg mL −1 )] = 0.372  × log IC50 ( μ g mL −1 ) +2.024 [16, 17], the value of the LD50 was calculated in order to orientate the in vivo experimental assays.…”

In vitro and in vivo safety evaluation of Dipteryx alata Vogel extract

“…Thus, the value of the LD50 for extract was 705 mg/kg [9], which justifies the use of 0.5 g/kg, chosen for in vivo experimental.…”

“…In previous studies [9] the IC50 was determined and the obtained value was used to calculate the LD50. Here, we used in vitro (Ames test) and in vivo (developmental and reproductive toxicology) assays to evaluate the mutagenic properties of D. alata barks extract and its effects on reproduction.…”

Óleo essencial de Baccharis trimera (Less.) DC.

“…Apesar de ampla utilização dos produtos naturais, pouca informação encontra-se disponível sobre os constituintes de tais extratos, bem como sobre os riscos oferecidos à saúde humana. Assim, estudos in vitro e in vivo acerca da genotoxicidade e mutagenicidade de plantas medicinais têm crescido juntamente com o aumento do uso terapêutico e com o interesse de comprovação da eficácia das mesmas nas mais diversas finalidades farmacológicas (Della Torre et al, 2011;Esteves-Pedro et al, 2011;Serpeloni et al, 2011;Cariddi et al, 2012;Esteves-Pedro et al, 2012;Raymundo et al, 2012;Resende et al, 2012;Santos et al, 2012;Vieira et al, 2012;dos Santos et al, 2013;Rebouças et al, 2013).…”