Proceedings [of] 10th Asian chemical congress: Sessions. 2. Medical chemistry & natural products. Hanoi, 2003

Up one level

Chemical and olfactorily interesting constituents of flower essential oil of Aglaia odorata lour

The odour of the essential oil from the flowers of Aglaia odorata Lour. was evaluated as at first fatty-greasy, then flowery, like hay, tea and methyl jasmonate, woody; it becomes very pleasant after two hours on the smelling strip.By a combination of GC-MS supported by the retention indices and NMR analyses, 69 compounds, among which 40 were isolated, representing 93.7% of the essential oil were identified. Cadinanes (ca 48%) and cyclocadinanes (6%) are main components. A main sesquiterpenoid constituent is muurola-4.10(14)-dien-1beta-ol (3. 5%) accompanied by the new epimeric cadina-4.l0(14)-dien-lalpha-ol (0.5%). Methyl jasmonate (3.6%) and methyl epi-jasmonate (0.4%) obviously make an important odour contribution.

Chemical composition of the volatile fraction of canarium album (Lour.) raeusch. essential oil from Vietnam

The composition of the leaf oil of Canarium album (Lour.) Raeusch. from Northwestern Nghe An province. Vietnam is reported. The essential oil content was 0.1%. More than 50 compounds could be detected of which nearly the same constituents were identified. The main components of the oil obtained from fresh leaves were beta-myrcene (23.7%) and beta-caryophyllene (15.0%). The olfactorilly valuable compounds that were found with concentration higher than 0.1% were: (Z)-3-hexan-1-ol acetate. 1-hexyl acetate, terpinen-4-ol, salicylic acid methylester, beta-ionone, nerolidol, cishexenylbenzoate; 2.6-octadien-1-ol-3.7-dimethyl acetate, muurulol, 2- pentadecanone, 6.10.14-trimethyl and phytol.

Discrimination and prediction of pharmacological activity of chemicals based on TFS

This paper describes TFS-based artificial neural network (TFS/ANN) approach for classification and prediction of pharmacological active classes of chemicals. Dopamine antagonists of 1.227 that interact with different type of receptors (Dl, D2, D3 and D4) were used for the training. The TFS/ANN successfully classified 89% of the drugs into their own active classes. Then, the trained model was used for predicting class unknown compounds. For the prediction set of 137 drugs that were not included in the training set, the TFS/ANN model predicted 111 (81%) drugs of them into Iheir own active classes correctly. TFS method was also employed for similar structure searching and identification of active molecular analogues. The TFS successfully identified structurally similar molecular analogues of our interest.

Flavonoids from polygonum hydropiper L.(Polygonaceae)

Four flavonoids were isolated from the leaves of Polygonum hydropiper L. (Polygonaceae) and identified as quercetin, quercetin-3-O-rhamnoside (quercitrin), quercetin-3-sulphate and (+)-catechin. Their structures were established on the basis of chemical evidence and spectroscopic techniques, including 2D NMR methods.

Natural anti-HIV agents: New 3-O-acyl betulinic acids from Strychnos vanpruckii (Loganiaceae)

Three new betulinic acid derivatives, 3beta-O-trans-feruloyl betulinic acid (1), 3beta-O-cis-feruloyl betulinic acid (2) and 3beta-O-cis-coumaroyl betulinic acid (4) along with two known triterpenes, 3beta-O-trans-coumamyl betulinic acid (3) and ursolic acid (6) were isolated from the leaves and twigs of Strychnos vanpruckii (Logamiaceae). All isolates showed moderate anti-HIV activity with IC50 values ranging from 9.5 to 20 mg/ml. The structures of the new isolates were eluciduted by spectroscopic techniques including 1D and 2D NMR spectroscopy.

Research on application of HPLC for quantitative and qualitative analysis of some multicomponent pharmaceuticals

By the developing of pharmaceutical branch, more and more multicomponent drugs have been proceduring and researching in many pharmaceutical factories. Many combination have been using but have not been included in Pharmacopoeias. Measurements were carried on some combined products containing multicomponent by high performance liquid chromatography (HPLC) methods to develope the adequate procedure. Obtained results showed that HPLC for identification and assay of combined drugs suitable and fast. The HPLC procedures established are good simpicity, accuracy and precise. These HPLC procedures should be used in standard of drugs if condition allowed.

Robust modelling of admet properties

Study on simultaneous assay of dextromethorphan hydrobromid, chlorpheniramine maleate, phenylpropanolamine hydrochloride and paracetamol in cough and cold tablets by HPLC

Pharmaceuticals containing dextromethorphan hydrobromide (DH), chlorpheniramine maleate (CM), phenylpropanolamine hydrochloride (PH) and paracetamol (PA) is one of the popular formulations for cough and cold treatment. This formulation has not been included in pharmacopoeias. With isocratic elution on RP 18 column (250 x 4 mm; 10 Mm) using a 1L mixture of water-acetonitril-triethylamine-phosphoric acid (650:350:3:1) containing 2.5g potassium dihydrophosphate as mobile phase, good separation was achiewed. UV detection was set at 216 nm for DH, CM and PH and at 222 nm for PA. The method showed good linearity in a wide range of working concentrations (0.03-0.48 mg.ml', 0.005-0.04 mg.ml', 0.025-0.20 mg.ml' and 0.01-16 mg.ml' for DH, CM, PH and PA respectively). The accuracy of method is proved good (percentage of recovery varied from 98.5 to 99.4% for all components), and precision is so high (relative error was less than 1.91 %). The method has been used as analytical protocol for quality control of this kind of drug within our institution.

Tautomeric schiff base adducts: (+-)-gossypol-amine under the imine form and (+-)-gossypol-amine under the enamine form can be well distinguished by physical methods and by their biological activities

Tautomeric Schiff bases adducts (+-)-gossypol-amine under the imine from and (+-)-gossypol-amine under the enamine form can be well distinguished by physical methods such as 1H-NMR and by their biological activities such as Brine shrimp cytotoxicity assay and antimalarial against Plasmodium falciparum.

Terpene lactones of Ginkgo biloba as antagonists at alpha1beta2gamma2L GABAa receptors

The medicinal properties of Ginkgo biloba leaves are exploited worldwide for the symptomatic treatment of dementia and cerebral and peripheral insufficiency and are delivered in a form of a special leaf extract. Literature indicates that apart from improving cerebral of GABAergic neurotransmission. Enhancel synaptic transmission in the hipocampus indicates enhanced cognition and bilobalide has been shown to increase excitation of neurones in the CA1 hippocampus and GABA-mediated inhibitory neurotransmission was suggested as possible mechanism. This conference paper discuses the effects of terpene lactones on direct GABA-mediated current from human alpha1beta2gamma2L GABAa receptors (the major GABAa receptor combination in the brain) expressed in Xenopus oocytes using 2-electrode voltage clamp electrophysiology.