We proposed pharmacognostical studies in the prime of molecular biology, citing the systematic studies of Panax drugs and Curcuma drugs. Each study was composed of three approaches, phylogenetic analysis of plants based on nuclear 18S rRNA and chloroplast trnK gene sequences, molecular authentication of herbal drugs, and quality evaluation on bioactive chemical constituents or pharmacological effect. Parsimony analysis of the combined trnK-18S rRNA gene sequence data yielded a well-resolved phylogeny within genus Panax. Based on species-specific sequences of the 2 genes, all the Panax drugs could be identified, furthermore, multiplex amplification refractory mutation system assay was developed for the authentication of 5 important drugs. Quantitative analysis on 11 saponins revealed that each taxon possessed its own characteristic pattern. The trnK/18S rRNA gene sequences could be used not only for an ultimate authentication but also for a speculation of the chemical constituent pattern that affects pharmacological effects. By the same molecular analysis as genus Panax, the potential method for identification of Chinese and Japanese Curcuma species was developed, making it possible to identify Curcuma drugs unambiguously. Using 5 drugs, we examined the effects on vasomotion in rat aortic rings as one index against "Oketsu." All methanol extracts exhibited intense NO-independent relaxation effects. All water extracts showed relaxation effects as the sum of the methanol-soluble compounds-induced relaxation and polysaccharides-induced contraction. Only the water extract of C. zedoaria showed NO-dependent relaxation besides NO-independent relaxation which is common to the other drugs, suggesting the drug derived from C. zedoaria has the potential to cure Oketsu with its various acting points. Such a series of studies will become necessary for standardization of herbal drugs and for their efficient uses.
The present study was performed to evaluate Toyama original brand formulation A and B about the scavenging activity for superoxide anion and hydroxyl radical by using electron spin resonance method and protective activity against nitric oxide (NO) donor-induced neuronal death in cultured cerebellar granule cells. As a result, both formulation A and B showed strong radical scavenging effects. It appeared that Corydalis turtschaninovii Besser forma yanhuso Y.H.CHOU et C.C.HSU and Magnolia obovata THUNBERG which were not contained in prescription B, had strong scavenging activities for superoxide anion and hydroxyl radical with the analysis for constituents of the formulations. Furthermore, both formulation A and B had protective effects against NO donor-induced neuronal death in cultured cerebeller granule cells. The protective effect of formulation A was somewhat stronger than that of formulation B. Corydalis turtschaninovii and Magnolia obovata also had protective activities against NO-mediated neuronal death. From these findings, Toyama original brand formulation A may be more useful than formulation B for maintaining and improving health.
Sairei-to (TJ-114), a traditional Japanese medicine, has been used clinically for the treatment of various edematous disorders. The inhibitory effect of TJ-114 on edema may be dependent on the diuretic response it invokes. The present study was performed to determine the effect of TJ-114 on the anti-diuretic hormone vasopressin, which is implicated in the retention of water in various edematous disorders. TJ-114 (0.5-1.5 g/kg) was administered intra-duodenally to pentobarbital-anesthetized rats. Specimens of the renal cortex were isolated 30min after the administration and incubated in buffered Hank's balanced salt solution with vasopressin. The vasopressin-stimulated cAMP production was dose-dependently attenuated in renal tissues in rats treated with TJ-114. The inhibitory effect of TJ-114 was diminished by pre-treatment with NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor. Therefore, TJ-114 may inhibit stimulation of the vasopressin V2 receptor which is closely related to nitric oxide production.
The hypoglycemic and hypolipidemic activity of Samallanthus sonchifolius (Compositae) was investigated in KK-Ay mice, an animal model of genetically type 2 diabetes. The water extract of the leaf of Samallanthus sonchifolius (Yacon) (500 mg/kg body weight) reduced the blood glucose (p<0.01) and cholesterol (p<0.05) of KK-Ay mice 6 weeks after repeated administration. However, Yacon did not affect the blood glucose in normal mice. Yacon also improved hyperglycemia after glucose tolerance. These results suggest that Yacon is useful for hyperglycemia and hyperlipidemia of type 2 diabetes.
A new preparation (PanaWang) containing eleven crude drugs was devised for self-medication to relieve subjective symptoms attendant to life-style diseases. The inhibitory effects of oral administration of PanaWang on the "accelerated atherosclerosis model" in intimal formation in rat carotid arteries after balloon endothelial denudation was examined. Administration of PanaWang 3 days before and 7 days after denudation dose-dependently suppressed the increased intimal thickening. In immunohistochemical analysis performed using a monoclonal anti-proliferating cell nuclear antigen (PCNA) antibody to stain vascular smooth muscle cells (VSMCs) in the intimal area, administration of PanaWang for 10 days reduced the proliferation of VSMCs. The inhibitory potency of PanaWang on VSMC proliferation partly contributes to its preventive effect on intimal thickening. These results indicated that, PanaWang might be useful for preventing atherosclerosis after endothelial injury resulting from long-term inappropriate life-styles.
A total of 26 herbal medicines were examined for their inhibitory effects on cytochrome P450 3A4 (CYP3A4) and 2D6 (CYP2D6). A methanol extract of each herbal medicine was prepared and then preincubated with human liver microsomes in the presence of an NADPH-generating system. Residual microsomal CYP3A4 and CYP2D6 activity was then determined by measuring the N-demethylation of erythromycin and the O-demethylation of dextromethorphan, respectively. Of the 26 herbal medicines tested, 16 were found to decrease the residual CYP3A4 activity in a preincubation time-dependent manner. The extract of Evodia Fruit caused the most dramatic decrease in residual CYP3A4 activity (i.e. 22.3% residual activity after 30 min preincubation). A substantial decrease in residual CYP3A4 activity was also observed from extracts of Sappan Wood, Incised Notopterygium Rhizome, Schisandra Fruit, Great Burdock Achene, Angelica Dahurica Root and Rhubarb (residual activity of 40.6, 41.2, 53.4, 47.1, 53.4 and 59.2% after 30 min preincubation, respectively). These results are comparable to those using troleandomycin, a known irreversible inhibitor of CYP3A4, which gave a residual activity of 49.4% under identical conditions. We found 5 herbal medicines that showed a preincubation time-dependent inhibition of CYP2D6. The extract of Incised Notopterygium Rhizome caused the most dramatic decrease in residual CYP2D6 activity (i.e. 61.9% residual activity after 30 min preincubation). These results suggest that extracts of herbal medicines contain metabolism-dependent inhibitors of CYP, especially CYP3A4.