Evaluation of oral toxicity and genotoxicity of Achyranthis Radix extract

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Achyranthes bidentata Blume, Achyranthis Radix (AR), is used as a traditional medicine ingredient in East Asia. It has anti-inflammatory, anti-oxidative, and anti-diabetic activities.

AIM OF THE STUDY

In the present study, we aimed to evaluate the oral toxicity and genotoxicity of single-dose and 4-week repeated-doses of AR hot water extract (ARE), under the good laboratory practice principles.

MATERIALS AND METHODS

For oral toxicity studies, SD rats (n = 5 per sex and group) were administered ARE at concentrations of 500, 1000, and 2000 mg/kg/day once (single dose) or once per day for 4 weeks (repeated dose). The non-clinical genotoxicity study consisted of bacterial reverse mutation using Escherichia coli (WP2 uvrA) and Salmonella typhimurium (TA98, TA100, TA1535, and TA1537), in vitro chromosomal aberration test with Chinese hamster lung cells (CHL/IU), and in vivo mouse bone marrow micronucleus test using bone marrow cells collected from male ICR mice (n = 5) that were orally administered ARE.

RESULTS

In the single-dose oral toxicity study, mortality and treatment-related changes in body weight were not observed throughout the study, and the lethal dose was estimated to be > 2000 mg/kg in rats. In the 4-week repeated-dose oral toxicity study, ARE did not induce significant changes in body weight, organ weight, food intake, or hematological and serum biochemical parameters in any group. In the bacterial reverse mutation test, ARE did not induce gene mutations in any tested strain. In the chromosomal aberration test, ARE did not cause chromosomal aberrations. The micronucleus test showed no significant increase in the number of micronucleated polychromatic erythrocytes or the mean ratio of polychromatic to total erythrocytes.

CONCLUSIONS

These results showed that ARE does not induce oral toxicity and genotoxicity in the in vivo and in vitro test systems.

Oral Administration of Achyranthis radix Extract Prevents TMA-induced Allergic Contact Dermatitis by Regulating Th2 Cytokine and Chemokine Production in Vivo

Allergic contact dermatitis (ACD) remains a major skin disease in many countries, necessitating the discovery of novel and effective anti-ACD agents. In this study, we investigated the preventive effects of Achyranthis radix extract (AcRE) on trimellitic anhydride (TMA)-induced dermatitis and the potential mechanism of action involved. Oral administration of AcRE and prednisolone (PS) significantly suppressed TMA-induced increases in ear and epidermal thickness, and IgE expression. In addition, abnormal expression of IL-1β and TNF-α protein and mRNA was also significantly attenuated by oral administration of AcRE. Treatment with AcRE also significantly suppressed TMA-induced IL-4 and IL-13 cytokines and mRNA expression in vivo. Moreover, AcRE strongly suppressed TMA-induced IL-4 and IL-5 production in draining lymph nodes, as well as OVA-induced IL-4 and IL-5 expression in primary cultured splenocytes. Interestingly, AcRE suppressed IL-4-induced STAT6 phosphorylation in both primary cultured splenocytes and HaCaT cells, and TMA-induced GATA3 mRNA expression ex vivo. AcRE also suppressed TMA-mediated CCL11 and IL-4-induced CCL26 mRNA expression and infiltration of CCR3 positive cells. The major compounds from AcRE were identified as gentisic acid (0.64 ± 0.2 μg/g dry weight of AcRE), protocatechuic acid (2.69 ± 0.1 μg/g dry weight of AcRE), 4-hydroxybenzoic acid (5.59 ± 0.3 μg/g dry weight of AcRE), caffeic acid (4.21 ± 0.1 μg/g dry weight of AcRE), and ferulic acid (14.78 ± 0.4 ± 0.3 μg/g dry weight of AcRE). Taken together, these results suggest that AcRE has potential for development as an agent to prevent and treat allergic contact dermatitis.