Table of Content

15 March 1999, Volume 8 Issue 1

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Full Papers

Three New Alkaloids from the Roots of Stemona tuberosa Lour

Lin Wenhan, Fu Hongzheng

1999, 8(1):  1-7. 

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From the roots of Stemona tuberosa Lour, three new alkaloids, named tuberostemoenone (1), N-oxy-tuberostemonine (2), isodidehydrotuberostemonine (3), together with three known alkaloids didehydrotuberostemonine (4), tuberostemonone (5) and oxotuberostemonine (6)were isolated, and their struetures were identified by various spectral analyses (IR, MS, 1H, 13C NMR,1H-1H COSY, NOESY, HMQC, HMBC) as well as 1H NMR line broadening effect.

A New Cerebroside from Lens culinaris Medic

Hong Yongfu, Zhu Yujun, Yang Genjin, GuoXuemin, Sun Lianna

1999, 8(1):  8-10. 

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Eight components were isolated from the seeds of Lens culinaris Medic. Basedon chemical and spectroscopic analysis, 7 of them were identified as β-sitosterol, β-sitosterylpalmitate, β-sitosterol-3-O-β-D-glucopyranoside, palmitic acid, 9, 10-dihydroxyoctadecanoic acid, ethyl-α-D-glucopyranoside, and 3-O-methyl-D-chiro-inositol. The other one was a new cerebroside, named culinariside.

Pterolactone, A New Norsesquiterpene Lactonc from Pterocarya stenoptera

Zhou Guangxiong, Zhang Yanjun, Peng Danming, Yu Dequan, Chen Yunfang

1999, 8(1):  11-14. 

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A new norsesquiterpene lactone, named pterolactone (1) was isolated from theleaves of Pterocarya stenoptera, together with five known compounds. The structure of the newcompound was determined by spectral analysis and by comparison with those of the relativecompounds.

Preliminary Study of Dual Characteristics of Antioxidation and Prooxidation of Flavonoids

Lu Jingfen, Li Ting, Jin Duo, Shen Chuanyong, Wang Kui, Yin Junjie

1999, 8(1):  15-20. 

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Flavonoids were comparatively studied as the scavengers of hydroxyl and superoxide flee radicals by means of spin trapping-electron spin resonance(ESR) method. The relative activity is related to molecular structures, i.e., the number and position of hydroxyl groups. With molecular modeling and quantum chemistry calculation methods, the relationships were also revealed from the structural analysis of the flavonoids and the products of their single electron oxidation. The spin labeling ESR results indicate that some flavonoids Can influence the conformation of membrane protein, which is likely due to oxidative damage. Both antioxidation and prooxidation characteristics of flavdnoids are worth further studying in detail.

Synthesis, Antibacterial and Antitumor Activity of 3-Me thy1-7-oxo-9-fluoro-10-alkyloxy (or Aryloxy)-2,3-dihydro-7H pyrido[1,2,3-de] [1,4]benzoxazine-6-carboxylic Acids and An alogues

Zhou Weicheng, Liu Jinqian, Yu Aizhen, Chen Xiuhua, Zhang Xiuping

1999, 8(1):  21-25. 

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Some 3-methyl-7-oxo-9-fluoro-10-alkyloxy (or aryloxy)-2, 3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acids and analogues were synthesized. The in vitro antibacterial tests showed that the effect of the 10-alkyloxy compounds (especially the fluoroethyloxycompound 3d) was much better than that of the 10-hydroxy compound 3a. The antitumor test showedthat some target compounds possessed moderate or low cytotoxicity against LAX and P388 in theculture.

Synthesis and Enhancing Effect of 5,9-Dimethyl-1-decanol on the Transport of 5-Fluorouracil and Tramadol Hydrochloride Across the Excised Rat Skin

Hanif Raja, Ping Qineng^*, Mo Fenzhu, Liu Guojie

1999, 8(1):  26-33. 

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New alcohol derivative of tetrahydrogeraniol (THG), an acyclic monoterpene,has been synthesized by reacting THG with Grignard reagent and ethylene oxide. The enhancingeffect of the synthesized derivative, 5,9-dimethyl-1-decanol (DIMDOL) on the penetration of 5-fluorouracil (5-FU) and tramadol hydrochloridc across the excised rat skin was studied by an in vitropermeation technique using two chamber diffusion cells. Azone and THG were used as standardenhancers for comparison. DIMDOL enhanced the permeability of 5-FU and tramadol hydrochloride18.60 fold and 73.19 fold across full-thickness skin with a lag time of 3. 35 h and 1.20 h respectively.Increased partition coefficient and diffusion coefficient values were obtained by this enhancer. Theseresults suggest that DIMDOL mainly affects the stratum corneum and interacts with both lipid-richlayers and keratin-rich layers.

The Study on Skin Permeation of Melatonin

Hao Jinsong, Zhu He, Zheng Junmin

1999, 8(1):  34-38. 

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The permeation of melatonin (MT) through the full-thickness mouse skin treated with penetration enhancers such as laurocapram (AZ), oleic acid (OA) and propylene glycol (PG),and/or iontophoresis under the condition with Ag/AgCl or Pt electrode at a current density of 0. 19 mA/cm², frequency of 2000 Hz and on/off ratio of 1:1 was conducted. MT as an unionized lipophilic drug could permeate through full-thickness mouse skin, whose steady-state flux and permeation coefficient were 1.622×10^-3 μg/cm²·s and 0.888×10^-6 cm/s, respectively. Penetration enhancers including 100% AZ, 5% AZ/PG and 10% OA/PG increased the steady-state flux of MT to 7.61, 7.03and 2.98 times compared with that through untreated skin, respectively. The flux of MT was enhanced by current application with Ag electrode with an enhancement factor of 2.19. These results showed that penetration enhancer AZ, OA and/or iontophoresis could enhance the skin permeation of MT.

NMR Studies on Fluorinated Iso-C-nucleoside Derivatives

Cui Yuxin, Zhang Huyi, Liu Xuehui, Ma Lingtai, Zhang Lihe^*

1999, 8(1):  39-42. 

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The NMR spectra of a series of iso-C-nucleosides and their fluoro derivatives were studied. Complete assignments of ¹H, ¹³C and ¹⁹F NMR chemical shifts were made and the influences of fluorine were discussed.

Effects of Nerve Growth Factor on the Glutamate-and Hydrogen Peroxide-induced Elevation of free Ca²⁺ Levels in Isolated Brain Cells from Neonatal Rats

Wu Junfang, Zhang Juntian

1999, 8(1):  43-47. 

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The effects of nerve growth factor (NGF) on glutamate-and hydrogen peroxideinduced elevation of intracellular free Ca²⁺ concentration ([Ca²⁺]i) in isolated brain cells from neonatal rats were studied. [Ca²⁺]i was measured by calcium fluorescent indicator Fura 2-AM in a spectrofluorophotometer. The results showed that the resting [Ca²⁺]i was 208±22 nmol·L^-1 (When the brain cells were incubated in Hanks' solution containing Ca²⁺ 1.3 nmol·L^-1). NGF did not alter the resting [Ca²⁺]i (in brain cells). NGF 1, 3, 10, 30 and 100 μg·L^-1 dose-dependently attenuatedglutamate (0.5 mmol·L^-1) and hydrogen peroxide (0.05 mmol·L^-1)-induced elevation of [Ca²⁺]i by 10%, 18%, 32%, 44%, 62% and 14%, 30%, 39%, 49%, 65% and their IC50 were 42.5 and 27.3 (95% confidence limits: 28.7-71.5 and 18.1-46.5) μg·L^-1 respectively. These results indicate that NGF protects cortical neurons against glutamate toxicity and oxidative insult via reducing the elevation of [Ca²⁺]i may be one of the mechanisms of protective effect.

Effects of IQ₂₃ on the Repolarization and Both Components of the Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytcs

Li Xinhua, Yan Sheng, Yao Weixing, Xia Guojin, Jiang Mingxing, Huang Wenlong, Peng Sixun

1999, 8(1):  48-52. 

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Using patch clamp whole cell recording techiques, we examined the effects of IQ23, a benzyl-isoquinoline derivative with antiarrhythmic activities, on the action potential (AP) and potassium currents in single guinea pig ventricular myocytes. The results showed that IQ23 at 10, 30and 100 μmol·L^-1 slowed the repolarization in AP dose-dependently. The APD90 were prolonged by15%, 28% and 31% respectively. This effect did not depend on the extracellular Ca²⁺. In voltage clamp mode, IQ23 effectively blocked both the components of the delayed rectifier potassium current (Ik), i.e., Iks and Ikr. At concentrations of 30 and 100 μmol·L^-1, IQ23 suppressed Iks by 21% and 26% and suppressed Ikr by 67% and 86% respectively. But even at 100 μmol·L^-1, IQ23 had little effect onthe inward rectifier potassium current (Ikl). It is concluded: (1) IQ23 can dose-dependently prolong APD in the ventriculas myocytes of guinea pig, the effect does not depend on the extracellular Ca²⁺; (2) IQ23 blocks both Iks and Ikr in the ventricular myocytes without obvious specificities between them.

Influence of Different Thyroid Status on Oxidative Metabo lism of Diazepam

Xu Fengyun, Zhang Yuan, Lou Yaqing

1999, 8(1):  53-58. 

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Experimental animal models of hypothyroidism and hyperthyroidism were established in SD rats and the influence of different thyroid status on oxidative metabolism ofdiazepam was studied. After a single oral dose of diazepam 30-40 mg.kg^-1 to the rats, the plasmaconcentration of desmethyldiazcpam and temazepam which are two principle metabolites ofdiazepam was determined by HPLC method. The plasma concentration of desmethyldiazepam wassignificantly higher in hypothyroid rats than in control rats and the elimination was inhibited. Itshowed that hypothyroidism inhibited C3-hydroxylation of desmethyldiazepam but did not influenceN-demethylation of diazepam. The plasma concentration of temazepam was decreased inhyperthyroid rats. The plasma concentration of desmethyldiazepam was decreased and theelimination was accelerated in mild and moderate hyperthyroid rats. On the contrary, the plasmaconcentration of desmethyldiazepam was increased and the elimination was inhibited in severehyperthyroid rats. The results suggested that hyperthyroidism inhibited C3-hydroxylation of diazepam,but did not influence N-demethylation of diazepam. Mild and moderate hyperthyroidism accelerated C3-hydroxylation of desmethyldizepam, however, severe hyperthyroidism inhibited this metabolic pathway.

Communication

Determination of Glycyrrhizic Acid and Chlorogcnic Acid in Compound Cough Granules by HPLC

Rong Zhifen, Xue Huijun, Zhang Weiqing, Wang Xinyu, Zou Anqing^*

1999, 8(1):  59-60. 

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