Safety assessment of oil extracted from lacquer (Toxicodendron vernicifluum (Stokes) F.A. Barkley) seed: acute and subchronic toxicity studies in rats

Abstract

Ethnopharmacological relevance: Toxicodendron vernicifluum (Stokes) F.A. Barkley (RVS) is an economic tree species and widely distributed in East Asia. Wood parts and raw lacquers of RVS have been used in coatings, herbal medicines or food supplements, and the leaves, flowers, roots, and fruits of RVS are also widely used in medicine traditionally. Lacquer seed oil (LSO) has potential health benefits and has not previously been evaluated for safety.

Aim of the study: The aim of the present study was to investigate the toxicological potential of LSO by acute and subchronic toxicity tests.

Materials and methods: The characterization of fatty acids of the LSO was carried out by gas chromatography. In the acute toxicity study, LSO was administered at single doses of 5000 or 10000 mg/kg by oral gavage. The subchronic toxicity study was conducted by daily oral administration of LSO at doses of 1250, 2500 and 5000 mg/kg/day for 30 consecutive days. The animals were evaluated for clinical observations, body weight, organ weight, feed consumption, biochemical and hematological parameters, and liver, lung, and kidney histology.

Results: There were no mortality and toxic changes were observed in acute toxicity study. The results of subchronic toxicity showed no toxicologically significant changes in clinical observations, body weight, organ weight, biochemical or hematological parameters. Histopathologic results indicated slight hepatic steatosis and inflammatory infiltration in the rats of 5000 mg/kg/day LSO treated group. However, the histopathologic observation was not confirmed by hepatic biochemical analysis.

Conclusions: These results suggested that the LD₅₀ of LSO is over 10000 mg/kg and LSO is non-toxic for SD rats in acute toxicity study. The no observed adverse effect level (NOAEL) of LSO in rats is considered to be 5000 mg/kg/day, and liver is the potential target organ of LSO for 30-day subchronic toxicity study.

Keywords: Acute oral toxicity; Histopathology; Lacquer seed oil; Sprague dawley rats; Subchronic oral toxicity.