|Phytomedicine. 2009 Dec;16(12):1144-50. |
|Vasodilatory actions of xanthones isolated from a Tibetan herb, Halenia elliptica.[Pubmed: 19403292 ]|
|In this study, six major xanthones, isolated and identified from Halenia elliptica were investigated for their vasodilatory actions in isolated rat coronary artery.
METHODS AND RESULTS:
The xanthones, including 1-hydroxy-2,3,5-trimethoxy-xanthone (HM-1), 1-hydroxy-2,3,4,7-tetramethoxy-xanthone (HM-2), 1-hydroxy-2,3,4,5-tetramethoxy-xanthone (HM-3), 1,7-dihydroxy-2,3,4,5-tetramethoxy-xanthone (HM-4), 1,5-dihydroxy-2,3-dimethoxy-xanthone (HM-5) and 1,7-dihydroxy-2,3-dimethoxy-xanthone (HM-7) caused vasodilation in the coronary artery pre-contracted with 1 microM 5-hydroxytryptamine (5-HT), with EC(50) values ranging from 1.4+/-0.1 microM (HM-1) to 6.6+/-1.4 microM (HM-2). The EC(50) values of the other xanthones were between those of HM-1 and HM-2. Removal of endothelium of the coronary artery led to decreases in the vasorelaxant effects of HM-1, HM-7 but not HM-2, HM-3, HM-4 and HM-5.
Our results showed that xanthones isolated from Halenia elliptica are vasoactive substances which exhibit either endothelium-dependent or endothelium-independent mechanisms in rat coronary artery. The potency and mechanism(s) of the vasorelaxant effects of these xanthones may be relevant to the structure-activity differences in the level and the position of the substituent groups with the primary xanthone structure.
|Arch Pharm Res. 2008 Jul;31(7):850-5. |
|Inhibitors of bone resorption from Halenia corniculata.[Pubmed: 18704326 ]|
|Eleven xanthones (1-11), three flavonoids (12-14) and three secoiridoids (15-17) were isolated from the aerial parts of Halenia corniculata.
METHODS AND RESULTS:
Among those compounds, 1-hydroxy-2,3,4,5-tetramethoxyxanthone (1), 1-Hydroxy-2,3,4,7-tetramethoxyxanthone (2), 1-hydroxy-2,3,4,5,7-pentamethoxyxanthone (3), 1-hydroxy-2,3,5-trimethoxyxanthone (4), 1,8-dihydroxy-3,5-dimethoxyxanthone (7), and luteolin (12), at the concentration of 1 microg/mL, effectively inhibited the osteoclast differentiation in a co-culture system with mouse osteoblastic calvarial cells and bone marrow cells. Notably, compounds 1, 3, and 4 exhibited, in a dose-dependent manner, significant inhibition of osteoclast differentiation even at a low concentration (0.01 microg/mL). All the inhibitory compounds, except for compound 7, significantly reduced the pit formation on the dentine slice compared with the control group. For the survival of the mature osteoclasts, compounds 1-4 and 12 (1 microg/mL), significantly decreased the survival number through induction of cell apoptosis, and compound 4 exhibited a significant inhibitory effect on osteoclast survival even at the low concentration of 0.1 microg/mL.