Non-clinical safety evaluation of salvianolic acid A: acute, 4-week intravenous toxicities and genotoxicity evaluations.

BACKGROUND: Toxicological problem associated with herbal medicine is a significant public health problem. Hence, it is necessary to elaborate on the safety of herbal medicine. Salvianolic acid A (SAA) is a major active compound isolated from Danshen, a popular herbal drug and medicinal food plant in China. The aim of the present study was to explore the toxicological profile of SAA. METHODS: The acute toxicity studies were performed in mice and Beagle dogs with single administration with SAA. A 4-week subchronic toxicity was test in dogs. SAA was intravenously administered at doses of 20, 80 and 300 mg/kg. Clinical observation, laboratory testing and necropsy and histopathological examination were performed. The genotoxic potential of SAA was evaluated by 2 types of genotoxicity tests: a reverse mutation test in bacteria and bone marrow micronucleus test in mice. RESULTS: In acute toxicities, the LD50 of SAA is 1161.2 mg/kg in mice. The minimum lethal dose (MLD) and maximal non-lethal dose (MNLD) of SAA were 682 mg/kg and 455 mg/kg in dogs, respectively. The approximate lethal dose range was 455-682 mg/kg. In the study of 4-week repeated-dose toxicity in dogs, focal necrosis in liver and renal tubular epithelial cell, the decrease in relative thymus weight, as well as abnormal changes in biochemical parameters, were observed in SAA 80 or 300 mg/kg group. The no observed adverse effect level (NOAEL) of SAA was 20 mg/kg. Thymus, liver and kidneys were the toxic targets. These toxic effects were transient and reversible. These results indicated that it should note examination of liver and kidney function during the administration of SAA in clinic. Furthermore, SAA had no mutagenic effect at any tested doses. CONCLUSION: These results provide new toxicological information of SAA for its clinical application and functional food consumption.

Therapeutic effect of a hydroxynaphthoquinone fraction on dextran sulfate sodium-induced ulcerative colitis.

AIM: To evaluate the therapeutic effect of hydroxynaphthoquinone mixture (HM) on dextran sulfate sodium (DSS)-induced colitis and explore the underlying mechanisms. METHODS: BALB/c mice received 3.5% DSS for 6 d to induce ulcerative colitis. Groups of mice were orally administered HM 3.5, 7 and 14 mg/kg and mesalazine 200 mg/kg per day for 7 d. During the experiment, clinical signs and body weight, stool consistency and visible fecal blood were monitored and recorded daily. A disease activity index score was calculated for each animal. At the conclusion of the experiment, the colonic histopathological lesions were evaluated. Myeloperoxidase (MPO) activity and tumor necrosis factor-α (TNF-α) levels were determined. Protein expression levels of TNF-α, nuclear factor-κB (NF-κB) p65, inhibitor of κB (IκB) and phosphorylation of IκB (p-IκB) were analyzed by Western blot analysis. RESULTS: Administration of 3.5% DSS for 6 d successfully induced acute colitis associated with soft stool, diarrhea, rectal bleeding, and colon shortening, as well as a loss of body weight. Administration of HM effectively attenuated the severity of colonic mucosa injury. For histopathological analysis, HM treatment improved histological alterations and lowered pathological scores compared with the DSS only group. This manifested as a reduction in the extent of colon injury and inflammatory cell infiltration, as well as the degree of mucosal destruction. In addition, HM at doses of 7 and 14 mg/kg significantly decreased MPO activity in colonic tissue (0.98 ± 0.22 U/g vs 1.32 ± 0.24 U/g, 0.89 ± 0.37 U/g vs 1.32 ± 0.24 U/g tissue, P < 0.05) and serum TNF-α levels (68.78 ± 7.34 ng/L vs 88.98 ± 17.79 ng/L, 64.13 ± 14.13 ng/L vs 88.98 ± 17.79 ng/L, P < 0.05). Furthermore, HM down-regulated the expression of TNF-α, NF-κB p65 and p-IκBα in colonic tissue while up-regulating IκBα protein expression. These results suggest that the significant anti-inflammatory effect of HM may be attributable to its inhibition of TNF-α production and NF-κB activation. CONCLUSION: HM had a favorable therapeutic effect on DSS-induced ulcerative colitis, supporting its further development and clinical application in inflammatory bowel disease.

Effectiveness of a hydroxynaphthoquinone fraction from Arnebia euchroma in rats with experimental colitis.

AIM: To evaluate the potential effectiveness of hydroxynaphthoquinone mixture (HM) in rats with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. METHODS: Colitis was induced by intracolonic administration of TNBS (80 mg/kg, dissolved in 50% ethanol). Rats were treated daily for 7 d with HM (2.5, 5, 10 mg/kg) and mesalazine 100 mg/kg 24 h after TNBS instillation. Disease progression was monitored daily by observation of clinical signs and body weight change. At the end of the experiment, macroscopic and histopathologic lesions of rats were scored, and myeloperoxidase (MPO) activity was determined. We also determined inflammatory cytokine tumor necrosis factor (TNF)-α level by ELISA, Western blotting and immunochemistry to explore the potential mechanisms of HM. RESULTS: After intracolonic instillation of TNBS, animals developed colitis associated with soft stool, diarrhea and marked colonic destruction. Administration of HM significantly attenuated clinical and histopathologic severity of TNBS-induced colitis in a dose-dependent manner. It abrogated body weight loss, diarrhea and inflammation, decreased macroscopic damage score, and improved histological signs, with a significant reduction of inflammatory infiltration, ulcer size and the severity of goblet cell depletion (all P < 0.05 vs TNBS alone group). HM could reduce MPO activity. In addition, it also decreased serum TNF-α level and down-regulated TNF-α expression in colonic tissue. This reduction was statistically significant when the dose of HM was 10 mg/kg (P < 0.05 vs TNBS alone group), and the effect was comparable to that of mesalazine and showed no apparent adverse effect. The underlying mechanism may be associated with TNF-α inhibition. CONCLUSION: These findings suggest that HM possesses favourable therapeutic action in TNBS-induced colitis, which provides direct pharmacological evidence for its clinical application.

Isolation and activity of an alpha-amylase inhibitor from white kidney beans.

An alpha-amylase inhibitor (alpha-AI) was isolated from white kidney beans (Phaseolus vulgaris L) by ethanol fractional precipitation, ion exchange chromatography and gel filtration column chromatography. It was a homogeneity glycoprotein demonstrated by SDS-PAGE and gel filtration on CL-6B. The glycoprotein contained 88.2% protein and was rich in aspartic acid, glutamic acid, leucine, threonine and serine. The carbohydrate moiety was consisted of Man, Glc, Gal and Xyl in a mole ratio of 2.42: 1.50: 1.52: 1.00. The glycan and the core protein backbone was connected by O-linkage as determined by beta-elimination reaction. The continuous oral administration of the alpha-AI (150 mg x kg(-1) x d(-1)) for 7 days can lower fasting blood glucose and 300 mg x kg(-1) x d(-1) alpha-AI for 7 days can improve the sugar tolerance on alloxan-dependent diabetic model rats. The result showed the alpha-AI obtained from white kidney beans had good hypoglycemic effect on alloxan induced diabetic rats and may have high potential pharmaceutical value as a regulative digestive-starch degradation in patients suffering from diabetes.