Oxidation by mercuric acetate of some triterpenoid derivatives containing an isopropenyl group
作者:J. J. H. Simes、T. G. Watson
DOI:10.1039/j39690002352
日期:——
The oxidation of the A-secolanosterol derivative 3-nitrilo-3,4-secolanosta-4(30),8-diene (IV) by mercuric acetate has produced the aromatic compound A-seco-1,2,3-trisnorlanosta-4(30),5(10),6,8-tetraene (VIII). When the cyanide group in (IV) was replaced by CO2H, CO2Me, or CONH2, the reaction did not occur. The aromatisation reaction also failed if the isopropenyl group was reduced [as in (IX)] or when
Ursolic acid and 2a-hydroxyursolic acid isolated from apple peels were found to show growth inhibitory activity against four tumor cell lines, HL-60, BGC, Bel-7402 and Hela. Structural modifications were performed on the C-3, C-28 and C-11 positions of ursolic acid and the cytotoxicity of the derivatives was evaluated. The SAR revealed that the triterpenes possessing two hydrogen-bond forming groups (an H-donor and a carbonyl group) at positions 3 and 28 exhibit cytotoxic activity. The configuration at C-3 was found to be important for the activity. Introduction of an amino group increased the cytotoxicity greatly. A 3 beta-amino derivative was 20 times more potent than the parent ursolic acid. The 28-aminoalkyl dimer compounds showed selective cytotoxicity. (c) 2005 Elsevier SAS. All rights reserved.
Comparison of combined spinal-epidural and low dose epidural for labour analgesia
作者:David L. Hepner、Robert R. Gaiser、Theodore G. Cheek、Brett B. Gutsche
DOI:10.1007/bf03018918
日期:2000.3
Purpose: To compare the combined spinal-epidural (CSE) technique with the epidural technique with regard to time to initiate and manage, motor block, onset of analgesia and satisfaction during labour.Methods: Upon requesting analgesia, 50 healthy term parturients were randomized in a prospective, double-blind fashion to receive either CSE analgesia or lumbar epidural analgesia in the labour floor of a university hospital at an academic medical centre. The epidural group (n=24) received bupivacaine 0.0625%-fentanyl 0.0002% with 0.05 ml in 10 ml local anesthetic sodium bicarbonate 8.4% and epinephrine 1:200, 000. The CSE group (n=26) received intrathecal 25 mu g fentanyl and 2.5 mg bupivacaine. Additional analgesia was provided upon maternal request.Results: There were no differences (P > 0.05) in time to perform either technique, motor blockade, or parturient satisfaction or in the number of times that the anesthesiologist was called to perform any intervention, Although the first sign of analgesia was not different between the two groups, the onset of complete analgesia was more rapid with the CSE technique (Visual Analogue Pain Score (VAPS) at five minutes < three: 26/26 vs 17/24, P +/- 0.001).Conclusion: Although epidural analgesia with a tow concentration of local anesthetic and opioid mixture takes longer to produce complete analgesia, it is a satisfactory alternative to CSE.
Hyaluronidase Inhibitory Activity of Pentacylic Triterpenoids from Prismatomeris tetrandra (Roxb.) K. Schum: Isolation, Synthesis and QSAR Study
The mammalian hyaluronidase degrades hyaluronic acid by the cleavage of the β-1,4-glycosidic bond furnishing a tetrasaccharide molecule as the main product which is a highly angiogenic and potent inducer of inflammatory cytokines. Ursolic acid 1, isolated from Prismatomeris tetrandra, was identified as having the potential to develop inhibitors of hyaluronidase. A series of ursolic acid analogues were either synthesized via structure modification of ursolic acid 1 or commercially obtained. The evaluation of the inhibitory activity of these compounds on the hyaluronidase enzyme was conducted. Several structural, topological and quantum chemical descriptors for these compounds were calculated using semi empirical quantum chemical methods. A quantitative structure activity relationship study (QSAR) was performed to correlate these descriptors with the hyaluronidase inhibitory activity. The statistical characteristics provided by the best multi linear model (BML) (R2 = 0.9717, R2cv = 0.9506) indicated satisfactory stability and predictive ability of the developed model. The in silico molecular docking study which was used to determine the binding interactions revealed that the ursolic acid analog 22 had a strong affinity towards human hyaluronidase.