Safety evaluation of syringic acid: subacute oral toxicity studies in Wistar rats

Abstract

Syringic acid (SA) is a phenolic acid and have been investigated for diverse pharmacological activities, but the safety and/or mechanism of toxicity is still lacking in the literature. Subacute toxicity studies will add value to its pharmacological profile and support its exploration as a future medicine. According to OECD TG 407 (OECD, 2008), rats were divided into 3 groups (n = 12). The dose of SA was decided by limit test. Treatment and satellite groups received SA (1000 mg/kg/day, p.o for 14 days), whereas an equal volume of vehicle was given to control groups. In order to access reversibility, satellite groups were kept for another 14 days post-treatment. The toxic signs, mortality and body weight changes were recorded. On day 15 and 29 the rats were anesthetized to collect blood for estimation of hematological and biochemical parameters and then sacrificed to collect internal body organ for weighing and histopathological studies. SA has no major adverse effect on the body weight, food intake, erythropoiesis, leucopoiesis and on internal body organs which was confirmed by evaluating various biochemical and hematological parameters, relative body organ weight and histopathological studies. Therefore, SA could be considered safe over limited period of time and this study may help researchers in establishing the doses for the longer-term subchronic studies. Further, subchronic and chronic toxicity studies are required to evaluate safety on long term use.

Keywords: Physiology; Polyphenol; Safety; Subacute; Syringic acid; Toxicity; Toxicology.

Fig. 1

The schematic illustration of experimental design.

Fig. 2

Body weight gain of rats in subacute toxicity studies of the SA. Values are expressed as mean ± SD (n = 6), *p < 0.05, **p < 0.01 compared to control group with statistical analysis by one-way ANOVA followed by Dunnett's post-hoc test. SA^t is a group of animals treated with syringic acid (1000 mg/kg) for 14 days and then sacrificed. SA^s is a satellite group treated with syringic acid (1000 mg/kg) for 14 days, no treatment for another 14 days and then sacrificed.

Fig. 3

Food consumption of rats administered daily doses of SA. Values are expressed as mean ± SD (n = 6), *p < 0.05, **p < 0.01 compared to control group with statistical analysis by one-way ANOVA followed by Dunnett's post-hoc test. SA^t is a group of animals treated with syringic acid (1000 mg/kg) for 14 days and then sacrificed. SA^s is a satellite group treated with syringic acid (1000 mg/kg) for 14 days, no treatment for another 14 days and then sacrificed.

Fig. 4

Histological results of vital internal body organs after oral administration of SA. SA^t is a group of animals treated with syringic acid (1000 mg/kg) for 14 days. SA^s is a satellite group treated with syringic acid (1000 mg/kg) for 14 days, no treatment for another 14 days.