We developed a new method for evaluating the hypoglycemic effects of Rehmanniae Radix (RehR), an herbal medicine, by monitoring the decrease in the sugar level of hyperglycemic silkworms. Preparation of a test sample obtained from 5 g of RehR, and quantification of the hypoglycemic effects of the sample using the hyperglycemic silkworm model was completed within 2 days. We further applied the newly established protocol to RehR extracts, and found that three of six samples showed hypoglycemic activity against hyperglycemic silkworms, whereas the other three samples did not. These results suggest that the hyperglycemic silkworm model is a useful alternative animal model to evaluate the hypoglycemic effects of RehR.
Mucolytic agents such as L-carbocisteine and ambroxol inhibited influenza-virus proliferation in animal model. L-carbocisteine has been shown to inhibit infections by influenza A virus (IAV) by reducing the expression of its receptor on human tracheal epithelial cells. On the other hand, the inhibitory effects of ambroxol on a replication of IAV are uncertain.To determine the inhibitory effects of ambroxol on IAV infection in MDCK cells, these cells were treated with ambroxol before and after IAV infection. Binding of IAV to sialic acid was not affected when MDCK cells were treated with ambroxol at concentrations of 16-250 μM after IAV infection. However, treating MDCK cells with 125 μM ambroxol before the infection markedly reduced the replication of IAV. These results suggested that ambroxol may have inhibited IAV infection by reducing the expression of its receptor on MDCK cells.