Acute toxicity and anti-fatigue activity of polysaccharide-rich extract from corn silk.

The aim of this study was to evaluate the safety and potential of PCS as the anti-fatigue functional food. PCS was prepared by water extracting-alcohol precipitating method, and its chemical compositions of monosaccharide were analyzed. Then, acute toxicity and anti-fatigue activity of PCS were evaluated. PCS is composed of Rha, Arab, Xyl, Man, Glu, and Gal, its molar ratio is 0.17: 0.30: 0.26: 0.35: 1.00: 0.57. No mortality and general symptoms of toxicity were observed in the PCS treated mice (7.5, 15, and 20g/kg body weight), the body weight and food consumption were not significantly changed compared with the normal control group. The relative weights of main organ, and biochemical indicators also did not markedly change. PCS can significantly prolong the duration of the swimming time to exhaustion in mice, decrease BUN, LA levels, increase LDH activities, and the contents of HG in the PCS treated mice. The dose of 400mg/kg body weight is the optimal dose for anti-fatigue activity both in male and female mice. In conclusion, PCS is a promising traditional natural-based therapeutic remedy for relieving fatigue with high safety.

Toxicological evaluation of Oviductus ranae: Acute, sub-acute and genotoxicity studies in mice and rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Oviductus ranae (OR) is a traditional animal-based Chinese medicine, which has been listed in the Chinese Pharmacopoeia since 1985 edition. Although its medicinal application has been widely acknowledged, there is little available information on its potential toxicity. AIM OF THE STUDY: The aim of this study was to investigate the acute, sub-acute, and genetic toxicities of OR. MATERIALS AND METHODS: In acute toxicity evaluation, OR was administered orally to mice at doses of 2.5, 5.0, 10.0, and 20.0g/kg BW for one time. Mortality, clinical signs, and body weight were observed for 14 days after treatment. In sub-acute toxicity evaluation, OR was administered orally to rats once a day for 28 consecutive days at doses of 1.75, 3.50, and 7.00g/kg BW. Animals were observed for general behaviors, mortality, food intake, and body weight changes. At the end of treatment, relative organ weight, pathology, hematological and biochemical parameters were monitored. In genotoxicity evaluation, bacterial reverse mutation assay (Ames test) was performed by treating OR with four different Salmonella typhimurium strains at doses of 8, 40, 200, 1000, and 5000µg/plate without or with S-9 mix, respectively. The genotoxicity of OR was also evaluated by micronucleus and sperm malformation assays in mice at doses of 2.5, 5.0, and 10.0g/kg BW, respectively. RESULTS: The results of acute toxicity study showed that the LD50 value of OR is higher than 20.0g/kg BW in mice. Death and abnormal clinical symptoms were not found during the period of experiment. In sub-acute toxicity, we found that the no-observed-adverse-effect levels (NOAEL) of OR in rats is up to 7.00g/kg BW. No statistically significant or toxicologically relevant defferences in body weight, food intake, relative organ weight, pathology, hematological and biochemical parameters were observed, when compared with control group. Results of Ames test, micronucleus and sperm malformation assays indicated that OR has no mutagenicity in vitro at a limited dose of 5000µg/plate, and dose not induce micronuclei and sperm malformation in mice at the dose of up to 10.0g/kg BW in mice. CONCLUSIONS: In conclusion, OR is a tranditional Chinese medicine with high safety.

Total synthesis of tubulysin U and its C-4 epimer.

The Tup fragments of tubulysins were synthesized with a tandem reaction as the key step, and unexpected diastereoselectivity was observed in the first Grignard addition stage. The coupling of the enolate of a thiazolyl ketone with chiral sulfinimines furnished the backbone of the Tuv fragment with over 100:1 d.r. and high yield. Thus, tubulysin U and C-4 epi-tubulysin U were prepared in a highly selective and efficient manner. The results of the MTT assay furthermore indicated that C-4 epi-tubulysin U maintained significant growth inhibition activities against several cancer cell lines.