Toxicological Evaluation of Camellia euphlebia Leaves Aqueous Extract Using Acute and Subacute Toxicity Studies in Mice and Genotoxicity Studies

Abstract

Camelliaeuphlebia is a novel food source and Chinese folk medicine with multiple pharmacological properties. Our previous exploration has demonstrated the antidepressant-like activity of Camellia euphlebia leaves aqueous extract by reliable animal models of depression; however, a lack of toxicological information limits its pharmacological application. The present study aimed to evaluate the preliminary safety of C. euphlebia extract by determining acute/subacute toxicity in mice and in vivo/in vitro genotoxicity. The oral-medium lethal dose of the extract in mice was found to be higher than 5000 mg/kg body weight in the acute toxicity study. In a 14-days subacute toxicity study, C. euphlebia extract at doses of 400, 800, and 1600 mg/kg did not result in significant changes in food intake, water intake, body weight, relative organ weight, aspartate aminotransferase activity, alanine aminotransferase activity, creatinine level, and number of white blood cells and red blood cells. However, histopathology observation of organs taken from all mice showed that 1600 mg/kg extract caused slight hydropic degeneration in the cytoplasm of hepatocytes. In a 28-days subacute toxicity study, 600 mg/kg extract significantly increased the level of red blood cells but produced no negative side effects on other pathological parameters. Mice treated with the extract at doses of 200, 400, and 600 mg/kg for 28 days did not manifest any histopathological alterations of the liver, kidney, and spleen. Additionally, the extract showed no chromosomal aberrations in the in vivo micronucleus test and in vitro chromosomal aberration test. The results revealed that the extract showed no significant toxic effects and no potential genotoxicity but with the likelihood of transient erythrocytosis and slight hepatotoxicity. Further chronic toxicological evaluation involved in more physiological parameters, especially associated with liver toxicity and erythropoietin level, would be needed to determine its safety and application value.

Figure 1

A detailed flowchart in text over the study design.

Figure 2

Effects of intragastric administration of CEAE for 14 consecutive days on the liver, kidney, and spleen histomorphology in mice. CEAE: C. euphlebia aqueous extract; CEAE1: 400 mg/kg; CEAE2: 800 mg/kg; CEAE3: 1600 mg/kg.

Figure 3

Effects of intragastric administration of CEAE for consecutive 28 days on the liver, kidney, and spleen histomorphology in mice. CEAE: C. euphlebia aqueous extract; CEAE1: 200 mg/kg; CEAE2: 400 mg/kg; CEAE3: 600 mg/kg.

Figure 4

Metaphase CHL cells exposure to various doses of CEAE or positive drugs under an optical microscope at 200× magnification: (a) vehicle control; (b) MMC (0.05 ug/mL) for 6 h treatment without S9 mixture; (c) CPA (10 ug/mL) for 6 h treatment with S9 mixture; (d) CEAE (750 ug/mL) for 6 h treatment without S9 mixture; (e) CEAE (1500 ug/mL) for 6 h treatment without S9 mixture; (f) CEAE (3000 ug/mL) for 6 h treatment without S9 mixture; (g) vehicle control; (h) MMC (0.05 ug/mL) for 24 h treatment without S9 mixture; (i) CPA (10 ug/mL) for 24 h treatment with S9 mixture; (j) CEAE (300 ug/mL) for 24 h treatment with S9 mixture; (k) CEAE (600 ug/mL) for 24 h treatment with S9 mixture; (l) CEAE (1200 ug/mL) for 24 h treatment with S9 mixture.

Figure 5

Micrograph of micronucleus in PCEs of murine bone marrow cells. Arrows indicate micronucleated PCEs; calibration bar −40 µm.