Acute oral toxicity of Insampaedok-san, a traditional herbal formula, in rats and its protective effects against ovalbumin-induced asthma via anti-inflammatory and antioxidant properties

BACKGROUND: Insampaedok-san (ren-shen-bai-du-san in Chinese) is a traditional herbal formula widely used for the treatment of respiratory diseases in Korea and China. In this study, we investigated the acute oral toxicity of an Insampaedok-san water extract (ISSE) in rats and the antiasthmatic effects of ISSE and its mechanism in a model of asthma induced by ovalbumin (OVA) in mice. METHODS: In a safety study, ISSE was administrated orally to rats of both sexes at single doses of 0 and 5000 mg/kg. We observed body weight changes, mortality, clinical signs, and gross pathological findings. In vitro antioxidant activity of ISSE was measured using 2,2-diphenyl-2-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging methods. A model of asthma was established in mice by sensitization and challenge with OVA. We assessed the levels of type 2 T-helper cytokines, chemokines, and immunoglobulin levels, using enzyme-linked immunosorbent assays, and superoxide dismutase (SOD) activity using a kit. RESULTS: No adverse effects were observed in the acute ISSE toxicity study. ISSE showed potent free radical scavenging activity and inhibited the recruitment of inflammatory cells into the lung and mucus hypersecretion in OVA-challenged mice. ISSE significantly decreased levels of interleukin (IL)-4, IL-5, eotaxin, and OVA-specific immunoglobulin (Ig)E, and increased SOD activity. CONCLUSIONS: These results indicate that ISSE is safe for human consumption and its antiasthmatic effect is associated with the ability of ISSE to attenuate inflammation and oxidative stress.