Angular-type furocoumarins from the roots of Angelica atropurpurea and their inhibitory activity on the NFAT signal transduction pathway.

One new (1) and two known angular-type (2,3) furocoumarins, isoarchangelicin (1), archangelicin (2), and 2'-angeloyl-3'-isovaleryl vaginate (3), were isolated from the roots of Angelica atropurpurea. The structure of the new compound was established on the basis of one- and two-dimensional NMR spectra and other spectroscopic studies. The inhibitory activity of these three compounds and a deacylated form of archangelicin (4) on the nuclear factor of activated T cells (NFAT) signal transduction pathway was tested by NFAT-responsive luciferase reporter gene assay in cultured cells. Although 4 did not exhibit inhibitory activity on NFAT signaling, 1-3 exhibited dose-dependent inhibition with IC50 values of 16.5 (1), 9.0 (2), and 9.2 (3) µM.

Enhancement of lipolytic responsiveness of adipocytes by novel plant extract in rat.

Subcutaneous adipocytes accumulate excess energy as triglycerides, but lipolytic response is less sensitive to catecholamines than visceral adipocytes. Obesity also induces catecholamine resistance of adipocytes. We have searched for crude drugs that could enhance the lipolytic response to noradrenalin. In this study, the lipolysis-promoting activities and action mechanisms of a novel plant extract from Hemerocallis fulva (HE) were investigated in isolated adipocytes from rat subcutaneous fat. HE exhibited no lipolysis-promoting activity alone but markedly promoted lipolysis when combined with noradrenaline; however, this synergistic activity was accompanied by no increase of intracellular cAMP production. This activity of HE was also observed when combined with cAMP analogue and was further enhanced by phosphodiesterase inhibitor. PKA inhibitor could reduce these activities of HE. These results indicate that HE is a novel lipolysis-promoting material that can sensitize the lipolytic response of adipocytes to catecholamine and suggest that HE can amplify the intra-cellular signaling pathway related to PKA or modify the other mechanism-regulating lipase activity. This characteristic material could contribute to improvement of adipose mobility in obesity-related disorder or in subcutaneous adiposity and to suppression of body fat accumulation.

Zoosporicidal activity of polyflavonoid tannin identified in Lannea coromandelica stem bark against phytopathogenic oomycete Aphanomyces cochlioides.

In a survey of nonhost plant secondary metabolites regulating motility and viability of zoospores of the Aphanomyces cochlioides, we found that stem bark extracts of Lannea coromandelica remarkably inhibited motility of zoospores followed by lysis. Bioassay-guided fractionation and chemical characterization of Lannea extracts by MALDI-TOF-MS revealed that the active constituents were angular type polyflavonoid tannins. Commercial polyflavonoid tannins, Quebracho and Mimosa, also showed identical zoosporicidal activity. Against zoospores, the motility-inhibiting and lytic activities were more pronounced in Lannea extracts (MIC 0.1 microg/mL) than in Quebracho (MIC 0.5 microg/mL) and Mimosa (MIC 0.5 microg/mL). Scanning electron microscopic observation visualized that both Lannea and commercial tannins caused lysis of cell membrane followed by fragmentation of cellular materials. Naturally occurring polyflavonoid tannin merits further study as potential zoospore regulating agent or as lead compound. To the best of our knowledge, this is the first report of zoosporicidal activity of natural polyflavonoid tannins against an oomycete phytopathogen.