In vivo efficacy and toxicity studies of a novel antibacterial agent: 14-o-[(2-amino-1,3,4-thiadiazol-5-yl)thioacetyl] mutilin.

A new pleuromutilin derivative with excellent antibacterial activity, 14-O-[(2-amino-1,3,4-thiadiazol-5-yl) thioacetyl] mutilin (ATTM), may serve as a possible lead compound for the development of antibacterial drugs. However, in vivo efficacy and toxicity evaluations of this compound have not been performed. In this study, we evaluated the efficacy of ATTM by measuring the survival of mice after a lethal challenge with methicillin-resistant Staphylococcus aureus (MRSA), and the 50% effective dose (ED50) was 5.74 mg/kg by the intravenous route. In an oral single-dose toxicity study, ATTM was orally administered to mice at different doses and the 50% lethal dose (LD50) was calculated to be 2304.4 mg/kg by the Bliss method. The results of the subchronic oral toxicity study in rats showed no mortality, exterior signs of toxicity, or differences in the total weight gain or relative organ weights between the treated groups and control group after administration. The hematological and serum biochemical data showed no differences between the treated and control groups, except for the levels of alkaline phosphatase (ALP), creatinine (CR) and blood glucose (GLU), which were significantly different in the high-dose group. The differences in the histopathological findings between the treated groups and the control group were not considered to be treatment-related. Our results indicated that the no observed adverse effect level (NOAEL) for ATTM was 5 mg/kg in this study.

Dietary supplementation of female rats with elk velvet antler improves physical and neurological development of offspring.

Elk velvet antler (EVA) has a traditional use for promotion of general health. However, evidence of EVA effects at different lifestages is generally lacking. This paper investigated the effects of long-term maternal dietary EVA supplementation on physical, reflexological and neurological development of rat offspring. Female Wistar rats were fed standard chow or chow containing 10% EVA for 90 days prior to mating and throughout pregnancy and lactation. In each dietary group, 56 male and 56 female pups were assessed for physical, neuromotor, and reflexologic development postnatally. Among the examined physical developmental parameters, incisor eruption occurred one day earlier in pups nursing dams receiving EVA. Among neuromotor developmental parameters, duration of supported and unsupported standing was longer for pups nursing EVA supplemented dams. Acquisition of neurological reflex parameters (righting reflex, negative geotaxis, cliff avoidance acoustic startle) occurred earlier in pups nursing dams receiving EVA. Longterm maternal EVA supplementation prior to and during pregnancy and lactation accelerated certain physical, reflexologic, and neuromotor developmental milestones and caused no discernible adverse effects on developing offspring. The potential benefits of maternal EVA supplementation on postnatal development warrants further investigation to determine whether EVA can be endorsed for the promotion of maternal and child health.

[Inhibitory action of Potentilla anserine polysaccharide fraction on H2O2-induced apoptosis of murine splenic lymphocytes].

A water-soluble polysaccharide fraction from root of Potentilla anserine was obtained. Gas chromatogram, FT-IR, physical and chemical characteristics of the Potentilla anserine polysaccharide fraction (PAPF) were analyzed. The protective effects of PAPF against the H2O2 induced process of apoptosis of murine splenic lymphocytes were investigated in vitro. Morphological assessment of apoptosis was performed with light microscope and laser scanning confocal microscope. DNA fragmentation was visualized by agarose gel electrophoresis. The amount of apoptotic cells was measured by flow cytometry. The results showed that PAPF is composed of rhamnose, arabinose glucose and galactose. H2O2 (200 micromol x L(-1)) induced apoptosis of murine splenic lymphocytes with the cell volume reduced, cytoplasm and nuclear shrunk and DNA stained non-uniformly. Condensed chromatin and formation of apoptotic body were observed in the apoptotic cells. Apoptotic bodies in the cells treated with PAPF and H2O2 were less than those in H2O2 treatment alone. DNA fragmentation assay showed that PAPF (50, 100, 200, and 400 microg x mL(-1)) obviously reduced H2O2-induced ladder bands. Flow cytometry analysis showed that H2O2 increased the populations of apoptotic sub-G1 cells from 5.60% (control) to 45.40%, and PAPF decreased H2O2-induced apoptosis to 37.80%, 22.70%, 17.70%, and 8.50%, respectively. In conclusion, PAPF reduced H2O2-induced oxidative damage in a dose dependent manner.

Antioxidant activities of Sophora subprosrate polysaccharide in immunosuppressed mice.

It is known that the reactive oxygen species (ROS) and free radicals play multiple roles in some pathological events. Sophora subprosrate polysaccharide (SSP1), a natural polysaccharide with a mean molecular weight of 2.24 x 10(4), isolated from the roots of Sophora subprosrate was studied for its antioxidant activities in mice. The in vivo investigation demonstrated that intraperitoneal administration of SSP1 was able to overcome cyclophosphamide-induced immunosuppression and significantly raised glutathione level, superoxidase dismutase activity, total antioxidant capacity, thymus and spleen indices in a dose-dependent manner in mice. The results showed that the SSP1, possessing pronounced free radical scavenging and antioxidant activities, may play an important role in prevention of oxidative damage in immunological system.

The Effects of Elk Velvet Antler Dietary Supplementation on Physical Growth and Bone Development in Growing Rats.

Elk velvet antler (EVA) has been used in traditional Oriental medicine for centuries to promote general health; however, little evidence for its effect on bone development is available. We investigated the effects of lifelong exposure of Wistar rats to a diet containing 10% EVA on physical growth and bone development. Measurements included weekly body weights, blood chemistry and kidney and testis/ovary indices (sacrificed at 5, 9, or 16 weeks of age), and bone traits of the femur bones by peripheral quantitative computed tomography (pQCT). Mean body weights were higher in the EVA group at 4-8 weeks in males and at 5 weeks of age in females. The kidney indices were greater in EVA dietary supplemented male rats at 5 and 16 weeks of age, in females at 16 weeks of age, and testis/ovary indices at 5 weeks of age. The femoral length was increased in both males and females at 5 weeks, and several pQCT-measured parameters had increased in EVA males and females. The activity of alkaline phosphatase (ALP) increased in EVA group while the content of calcium and phosphorus did not differ among groups. Our results seem to support a role for dietary supplementation of EVA on growth and bone development in this model.

Synthesis and evaluation of novel pleuromutilin derivatives with a substituted pyrimidine moiety.

A series of novel pleuromutilin derivatives possessing 6-hydroxy pyrimidine moieties were synthesized via acylation reactions under mild conditions. The in vitro antibacterial activities of the synthesized derivatives against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), Bacillus subtilis (B. subtilis), and Escherichia coli (E. coli) were tested by the agar dilution method. The majority of the screened compounds displayed potent activities. Compounds 3 and 6a were found to be the most active antibacterial agents against MRSA and MRSE. Moreover, in the vivo experiment, compound 6a showed comparable antibacterial activity to that of tiamulin, with ED50 of 5.47 mg/kg body weight against MRSA.

Hypericum perforatum extract therapy for chickens experimentally infected with infectious bursal disease virus and its influence on immunity.

Hypericum perforatum extract (HPE) has been proved a drug effective to many viral diseases. The purpose of this paper was to investigate the therapeutic efficacy and immuno-enhancement of HPE for chickens which were already challenged with infectious bursal disease virus (IBDV BC-6/85). Chickens infected with IBDV were treated with HPE for 5 consecutive days, the observation of immune organ indexes and pathological changes index, determination of IFN-α and detection of IBDV with RT-PCR were employed to assess in vivo whether or not HPE had the certain therapeutic efficacy on infectious bursal disease (IBD), and if HPE was able to improve the immunologic function. The results showed that 1330 and 667.9 mg/kg body weight (BW) per day of HPE had significant therapeutic efficacy and improvement immunologic functions for chickens infected experimentally with IBDV.

Inhibitory effect of carboxymethylpachymaran on cyclophosphamide-induced oxidative stress in mice.

The aim of the present study was to investigate the immunomodulatory effect and antioxidant activity of carboxymethylpachymaran on cyclophosphamide-induced immunosuppression in mice in vivo. The results showed that carboxymethylpachymaran could be used to overcome the cyclophosphamide-induced immunosuppression in mice. Moreover, it significantly increased the thymus and spleen indices, lysozyme, catalase and superoxidase dismutase activities, and total antioxidant capacity. In contrast, it decreased xanthine oxidase activity and malondialdehyde levels. The results indicated that carboxymethylpachymaran might play an important role in the prevention of oxidative damage in the immunological system.

Immunomodulatory activity in vitro and in vivo of polysaccharide from Potentilla anserina.

The polysaccharide (PAP) from Potentilla anserina was evaluated for modulating effects by using mouse peritoneal macrophage and the immunosuppressed-model cyclophosphamide-induced. Phagocytotic and mononuclear phagocytic system function assays showed that PAP stimulated the phagocytosis of phagocyte. Splenocyte proliferation assay showed that PAP acted the effect combining Con A or LPS in splenocyte proliferation. The parameters detected showed that PAP increased thymus and spleen indices, the levels of LDH and ACP in the spleen, and IL-10 and IFN-γ in serum in immunosuppressed mice. The results suggest that PAP is involved in immunomodulatory effects leading to the exploration for PAP as a potential immunostimulant.

Protective effect of a Potentilla anserine polysaccharide on oxidative damages in mice.

Potentilla anserine polysaccharide (PAP) was studied in vivo to investigate its antioxidant activity using the model of dexamethasone-induced oxidative stress in mice. The investigation demonstrated that PAP at 50, 100 or 200mg/kg body weight for 7 days respectively increased thymus index and spleen index, glutathione level, superoxidase dismutase activity and total antioxidant capacity in both thymus and spleen and decreased the content of H(2)O(2) in spleen and NO in both thymus and spleen of mice. The results revealed that PAP was able to overcome dexamethasone-induced oxidative stress and might play an important role in repairs of oxidative damage in immunological system.