A methanol extract of the bark of Bocconia arborea was fractionated on silica gel and the fractions analysed using gas chromatography coupled with mass spectrometry (GC-MS). Several benzophenanthridine alkaloids were identified including dihydrosanguinarine, oxysanguinarine, 11-acetonyldihydrochelerythrine, dihydrochelerythrine, chelerythrine, chelerythridimerine and angoline as the principal constituents. The results show that the direct GC-MS analysis of these alkaloids is possible with a clear distinction between the compounds. The technique is shown to be a valuable tool and an alternative technique to classical phytochemical procedures permitting the fast analysis of alkaloids mixtures.
Astianthus viminalis has been used as a medicinal plant for a long time owing to its many physiological actions such as anti-inflammatory and antidiabetic activities. A new tetracyclic triterpenoid 3beta,19alpha-dihydroxyurs-12,20(21)-diene-28-oic acid (1), known constituents oleanolic acid (2) and ursolic acid (3), and the coumarins 7,8-dimethoxycoumarin (4) and 7-methoxycoumarin (5) were isolated from the chloroform extract of the leaves of A. viminalis. The structure and relative configurations of 1 were determined by spectroscopic methods (1H- and 13C-NMR, IR, and MS) and 2D-NMR experiments. The hypoglycemic ingredients of A. viminalis were characterized as compounds 1-3. The hypoglycemic effect of the isolated natural product 1 was investigated in normoglycemic and streptozotocin (STZ)-induced diabetic mice. All effects were compared with those of tolbutamide. Triterpenoid 1 showed potent hypoglycemic and hypolipidemic effects in the STZ-induced diabetic mice. Continuous administration of 1 (30 mg/kg, orally) led to significant decrease in the level of glucose, triglycerides, total cholesterol, LDL, and VLDL in the diabetic mice, whereas the level of HDL did not alter significantly in any of the groups studied.
The methanol soluble fraction of the leaves of Buddleia scordioides after column chromatography resulted in the isolation of two known iridoid glucosides, catalpol and methylcatalpol. The structures were elucidated by extensive 1D-2D-NMR spectroscopy. The structure of methylcatalpol was confirmed by single-crystal x-ray diffraction. These compounds showed protective activity against increased (both chloroform and histamine) skin vascular permeability in rabbits. The protective effect was measured as the reduction in leakage of Evans blue. The results showed that the iridoids produced a significant inhibition of microvascular permeability. A comparison was made between the action of the iridoids and a known inhibitor of vascular permeability, troxerutin (50 mg/kg). Methylcatalpol and catalpol were found to be less effective than troxerutin.
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