Triterpene glycosides of Siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of maltose in rats

The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.     

Unbiased evaluation of bioactive secondary metabolites in complex matrices

The majority of bioactive principles in a complex matrix such as natural products and botanical medicines are secondary rather than primary metabolites. In addition to being chemically diverse, the bioactivity of an ethnobotanical can comprise from one to several bioactive compounds, present in a complex mixture. Conventional discovery efforts utilize bioassay-guided fractionation (BGF) to isolate individual active compounds. When applied to complex natural products, BGF is often challenged by an apparent loss of activity during fractionation, resulting in weakly active isolated compounds. Metabolomic analysis can potentially complement existing the BGF paradigm by capturing the chemical complexity of the metabolites. The proposed biochemometric approach establishes a link between the chemistry of a secondary metabolome and a deserved health impact, using a high-throughput, high-resolution capable biological endpoint. The proof of principle is demonstrated for the anti-tuberculosis (TB) activity of the Alaskan ethnobotanical, Oplopanax horridus. Biochemometric analysis identified the 100 most active constituents from thousands of metabolites in the active extract by means of 2D orthogonal chromatography using countercurrent and GC-MS methods. Previously isolated O. horridus phytoconstituents were used as reference markers of known structure and bio (in)activity. Positive correlations allowed distinction of anti-TB actives from inactive compounds. A total of 29 bioactives from 3 main structural classes were assigned based on MS data. Biochemometric analysis is a new tool for the standardization of herbal medicines and ethnobotanicals, as well as for drug discovery from nature. The method can assign multiple active compounds in complex mixtures without their prior isolation or structure elucidation, while still providing an interface to structural information.     

Dietary mannanase‐hydrolyzed copra meal improves growth and increases muscle weights in growing broiler chickens

The utilization of copra meal as a feed ingredient is limited because it contains a high level of mannan. However, recent findings indicate that the effect of copra meal on growth performance in broiler chickens can be improved by the supplementation of mannanase in the diet. In the present study, we examined the effect of mannanase‐hydrolyzed copra meal (MCM) on growth performance and muscle protein metabolism in growing broiler chickens (Gallus gallus domesticus). Forty 8‐day‐old male broiler chicks were assigned to two groups (four birds in each pen, five replicates) and fed either a commercial diet (as a control diet) or a diet containing MCM at 0.2% until 22 days of age. Dietary MCM significantly increased the weights of body, breast muscle, and thighs in chickens, whereas the weights of abdominal adipose tissue and liver were not affected. Cumulative feed intake was significantly increased by MCM. Dietary MCM significantly decreased plasma 3‐methylhistidine level. The messenger RNA and protein levels of muscle protein metabolism‐related factors were not altered by MCM. These findings suggest that the growth‐promoting effect of MCM is related to the suppression of muscle proteolysis in growing broiler chickens.     

Extraskeletal osteosarcoma with pulmonary metastasis in a female f344 rat

A subcutaneous mass in the right femoral region of a female F344 Slc/N rat was examined histopathologically. At 83 weeks of age, the animal showed symptoms of severe anemia and nasal bleeding. Necropsy revealed that the mass had invaded the skeletal muscles but did not affect the bones. Multicentric nodules were also observed in the lung. Histopathology revealed a sheet-like growth pattern of polygonal tumor cells with round or comma-shaped nuclei and pale eosinophilic cytoplasm. Osteoid tissue was observed in not only the original lesion but also the metastatic foci in the lung. Each tumor cell was surrounded by argentophil fibers and few collagen fibers. Immunohistochemically, the tumor cells were positive for proliferating cell nuclear antigen (PCNA), vimentin, osterix and osteocalcin, but negative for keratin, S-100, von Willebrand factor, CD-31, CD-34, desmin, α-smooth muscle actin, lysozyme, α1-antitrypsin and rat malignant fibrous histiocytoma (MFH) antigen. CD-68-positive cells were considered to be infiltrated macrophages because they were negative for PCNA. On the basis of these findings, we diagnosed the present case as extraskeletal osteosarcoma.     

Enzymatic high digestion of soybean milk residue (okara)

The objective of this study was to digest okara in high yield by food-processing enzymes. Autoclaving of okara was effective in increasing cellulase digestion for the primary cell wall, and the digestion was accelerated by the formation of single cells by stirring. Most of the residual okara after autoclaving and cellulase digestion was found to be the secondary cell walls compared with the cellulase-treated soybean single cells. The secondary cell wall was found to be composed of galacturonic acid, neutral sugars, and protein and was considered to be a complex of these compositions. Many cellulolytic and proteolytic enzymes could not digest the secondary cell wall; however, it was found that two pectinases could digest the secondary cell wall. A series of digestions resulted in yields of 83-85% from the raw okara, and the final residues were identified as oil body complexes in the soybean cells and fiber-like organ between the cells.     

Enzyme-linked immunosorbent assay with monoclonal and single-chain variable fragment antibodies selective to coplanar polychlorinated biphenyls

Coplanar polychlorinated biphenyls (Co-PCBs) consisting of non-ortho and mono-ortho-chlorinated PCBs are dioxin-like compounds and cause wide contamination in the environment. To monitor Co-PCB residues, it was attempted to establish an enzyme-linked immunosorbent assay (ELISA) with monoclonal and recombinant antibodies selective to Co-PCBs. When 3,3',5,5'-tetrachlorobiphenoxybutyric acid (PCBH)-keyhole limpet hemocyanin conjugate was immunized into mice, two monoclonal antibodies, Mab-0217 and Mab-4444, were obtained. 3,3',5,5'-Tetrachlorobiphenyl (PCB80) was determined with an IC(50) value of 2.6 and 0.46 ng mL(-1) in ELISA based on Mab-0217 and Mab-4444, respectively. Mab-4444 cross-reacted with Co-PCB congeners, except for PCB77 and PCB81. Mab-0217 reacted with PCB80 and cross-reacted with PCB111. A single-chain variable fragment (scFv) antibody derived from Mab-4444 was produced in recombinant Escherichia coli cells. The scFv antibody showed nearly the same sensitivity toward PCBH as the parent monoclonal antibody in ELISA. These results clearly suggested that Mab-4444 and its scFv antibodies were suitable for monitoring the representative congeners of Co-PCBs.     

Effect of prophylactic administration of hyperimmune plasma to prevent Rhodococcus equi infection on foals from endemically affected farms

The effect on foals of prophylactic administration of hyperimmune plasma to prevent R. equi infection was investigated on three farms at which R. equi infection was endemic. Sixteen foals between 10 and 39 days of age were intravenously given 1-21 of hyperimmune plasma. ELISA antibody titres against R. equi were significantly increased and maintained at high levels for over 30 days in most of the recipient foals. The prevalence of R. equi infection was 6.3% (1/16) in the foals that received the immune plasma, and 26.3% (5/19) in the control foals not given the immune plasma on the three farms. For 2 years before and after this field trial on the three farms, 18 of 64 foals (28.1%) showed clinical signs of respiratory tract infection and four of them died of R. equi pneumonia. Heavy contamination of horses and their environment with virulent R. equi was detected by colony blotting, and plasmid profiles also suggested that foals on the three farms were constantly exposed to virulent R. equi. The results of this field trial support previous observations by some researchers that the administration of hyperimmune plasma to foals in the early days of life promotes prevention of R. equi infection on endemic farms; however, the mechanism of hyperimmune plasma protection remains unclear.