1.[Chemical constituents from n-butanol extract of aerial part of Polygala sibirica].
Song Y1, Jiang Y, Bi D, Tian X, Liang L, Tu P. Zhongguo Zhong Yao Za Zhi. 2012 Feb;37(4):471-4.
Nine compounds were isolated from the n-butanol extract of the aerial parts of Polygala sibirica by various column chromatographic methods. Their structures were identified by MS and NMR spectroscopic data as sibiricaxanthone F (1), amentoflavone (2), linarin (3), zigu-glucoside I (4), 3, 6'-disinapoyl sucrose (5), tenuifoliside A (6), 2, 4, 4-trimethyl-3-formyl-6-hy-droxy-2, 5-cyclohexadien-1-one (7), lanierone (8), and aralia cerebroside (9) , respectively. Compounds 2, 3, 4, 7, 8 were isolated from the genus Ploygala for the first time, and compound 9 was firstly isolated from the title plant.
2.Selaginellin A and B, two novel natural pigments isolated from Selaginella tamariscina.
Cheng XL1, Ma SC, Yu JD, Yang SY, Xiao XY, Hu JY, Lu Y, Shaw PC, But PP, Lin RC. Chem Pharm Bull (Tokyo). 2008 Jul;56(7):982-4.
Two new unusual natural pigments were first isolated from the whole herbs of Selaginella tamariscina. The structure of selaginellin A (1) was established as (R,S)-4-[(4'-hydroxy-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]-2,5-cyclohexadien-1-one and selaginellin B (2) as (R,S)-4-[(4'-methoxy-4-(methyl)-3-((4-methoxyphenyl)ethynyl)biphenyl-2-yl)(4-methoxyphenyl)methylene]-2,5-cyclohexadien-1-one, along with four known biflavonoids, amentoflavone (3), hinokiflavone (4), heveaflavone (5), and 7''-O-methylamentoflavone (6). Their chemical structures were elucidated by spectral analysis of electrospray ionization mass spectroscopy (ESI-MS), one-dimensional nuclear magnetic resonance spectroscopy (1D-NMR) and two-dimensional-nuclear magnetic resonance spectroscopy (2D-NMR) including (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer (DEPT) and heteronuclear multiple bond coherence (HMBC), and single-crystal X-ray diffraction techniques.
3.Hydrolysis and photolysis of 4-Acetoxy-4-(benzothiazol-2-yl)-2,5-cyclohexadien-1-one, a model anti-tumor quinol ester.
Wang YT1, Jin KJ, Myers LR, Glover SA, Novak M. J Org Chem. 2009 Jun 19;74(12):4463-71. doi: 10.1021/jo9008436.
4-Acetoxy-4-(benzothiazol-2-yl)-2,5-cyclohexadien-1-one, 1, a quinol derivative that exhibits significant anti-tumor activity against human breast, colon, and renal cancer cell lines, undergoes hydrolysis in aqueous solution to generate an oxenium ion intermediate, 3, that is selectively trapped by N(3)(-) in an aqueous environment. The 4-(benzothiazol-2-yl) substituent slows the rate of ionization of 1 compared to analogues with 4-phenyl or 4-(p-tolyl) substituents, 4a or 4b. However, once generated, 3 is somewhat more selective than the 4-phenyl-substituted cation 5a. Calculations performed at the B3LYP/6-31G(d) level agree that the 4-(benzothiazol-2-yl) substituent does significantly stabilize 3. The structure of the major isolated azide adduct, 4-(6-azidobenzothiazol-2-yl)phenol, 9, confirms that the positive charge is highly delocalized in 3. The results of hydrolysis of 1 show that the 4-(benzothiazol-2-yl) substituent has a significant inductive electron-withdrawing effect as well as a significant resonance effect that is electron-donating.
4.Self-modeling curve resolution techniques applied to comparative analysis of volatile components of Iranian saffron from different regions.
Jalali-Heravi M1, Parastar H, Ebrahimi-Najafabadi H. Anal Chim Acta. 2010 Mar 10;662(2):143-54. doi: 10.1016/j.aca.2010.01.013. Epub 2010 Jan 18.
Volatile components of saffron from different regions of Iran were extracted by ultrasonic-assisted solvent extraction (USE) and were analyzed by gas chromatography-mass spectrometry (GC-MS). Self-modeling curve resolution (SMCR) was proposed for resolving the co-eluted GC-MS peak clusters into pure chromatograms and mass spectra. Multivariate curve resolution-objective function minimization (MCR-FMIN) and multivariate curve resolution-alternating least square (MCR-ALS) were successfully used for this purpose. The accuracy of the qualitative and quantitative results was improved considerably using SMCR techniques. Comparison of the results of saffron from different regions of Iran showed that their volatile components are different from chemical components and relative percentages points of view. Safranal is the main component of all samples. In addition, 4-hydroxy-2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde (HTCC), 2(5H)-furanone, 2,4,4-trimethyl-3-carboxaldehyde-5-hydroxy-2,5-cyclohexadien-1-one and 2(3H)-furanone, dihydro-4-hydroxy were common in all samples with high percentages.