Ionone derivatives from Alternanthera sessilis

The chloroform extract of the air-dried leaves of Alternanthera sessilis afforded a mixture of diastereomers of a new ionone derivative 1 whose structures were elucidated by extensive 1D and 2D NMR spectroscopy and mass spectrometry. Oxidative cleavage of 1 to aldehyde 3 with manganese dioxide confirmed diastereoisomerism arose from a racemic side chain chiral centre. Antimicrobial tests on the mixture of diastereomers and the derivative indicated that they have low activities against Pseudomonas aeruginosa and Trichophyton mentagrophytes.     

A new sesquiterpene from <Emphasis Type="Italic">Artemisia vulgaris</Emphasis>

The dichloromethane extract of the air-dried leaves of Artemisia vulgaris afforded a new sesquiterpene 1, caryophyllene oxide, phytyl fatty acid esters, squalene, stigmasterol and sitosterol. The structure of 1 was elucidated by extensive one- and two-dimensional nuclear magnetic resonance spectroscopy.     

E phage gene transfection enhances sensitivity of lung and colon cancer cells to chemotherapeutic agents

The E gene from ΦX174 encodes a membrane protein with a toxic domain that leads to a decrease in the tumour cell growth rate. With the aim of improving the antitumour effect on lung and colon cancer cells of the currently used chemotherapeutic drugs such as gemcitabine, carboplatin and paclitaxel, and 5-fluorouracil (5FU) plus folinic acid (FA) with irinotecan or oxaliplatine, we investigated a new combined therapy using these drugs associated to the transfection of E gene. Our results showed that E gene was able to decrease proliferation rate in A-549 and T-84 cells by inducing apoptotic the mitochondrial pathway. Significantly greater inhibition of proliferation was obtained using drugs in combination with E gene in comparison to single-agent treatments or controls. E gene combined with paclitaxel had the greatest effect on A-549 cells and combined with 5FU/FA/oxaliplatin on T-84 cells. Antitumour mechanisms of the chemotherapeutic drugs were enhanced by E gene, which itself has direct oncolytic effects inducing A-549 and T-84 apoptosis. Our in vitro results indicate that the combined therapy of E gene and cytotoxic drugs may be of potential therapeutic value as a new strategy for patients with advanced lung and colon cancer.     

Triterpenes from Euphorbia hirta and their cytotoxicity

AIM： To investigate the chemical constituents of the stems, leaves and roots of Euphorbia hirta, and to test for the cytotoxic and antimicrobial potentials of the major constituents of the plant. METHODS： The compounds were isolated by silica gel chromatography and their structures were elucidated by NMR spectroscopy. The cytotoxicity tests were conducted using the 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （MTT） assay, while the antimicrobial tests employed the agar well method. RESULTS： The air-dried stems of E. hirta afforded taraxerone 1, a mixture of 25-hydroperoxycycloart-23-en-3β-ol （2a） and 24-hydroperoxycycloart-25-en-3β-ol （2b） （sample 2） in a 2 ： 1 ratio, and another mixture of cycloartenol （3a）, lupeol （3b）, α-amyrin （3e） and fl-amyrin （3d） （sample 3） in a 0.5 ： 4 ： 1 ： 1 ratio. The air-dried leaves of E. hirta yielded sample 2 in a 3 ： 2 ratio, sample 3 in a 2 ： 3 ： 1 ： 1 ratio, phytol and phytyl fatty acid ester, while the roots afforded sample 2 in a 2 ： 1 ratio, sample 3 in a 2 ： 1 ： 1 ： 1 ratio, a mixture of cycloartenyl fatty acid ester 4a, lupeol fatty acid ester 4b, α-amyrin fatty acid ester 4c and β-amydn fatty acid ester 4d （sample 4） in a 3 ： 2 ： 1 ： 1 ratio, linoleic acid, β-sitosterol and squalene. Compound 1 from the stems, sample 2 from the leaves, and sample 3 from the stems were assessed for cytotoxicity against a human cancer cell line, colon carcinoma （HCT 116）. Sample 2 showed good activity with an ICs0 value of 4.8 μg.mL-1, while 1 and sample 3 were inactive against HCT 116. Sample 2 was further tested for cytotoxicity against non-small cell lung adenocarcinoma （A549）. It showed good activity against this cell line with an ICs0 value of 4.5 μg.mL-1. Antimicrobial assays were conducted on 1 and sample 2. Results of the study indicated that I was active against the bacteria： Pseudomonas aeruginosa and Staphylococcus aureus, but was inactive against Escherichia coli and Bacillus subtilis. Sample 2 was active against the bacteria： Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and fungi： Candida albicans and Trichophyton mentagrophytes. It was inactive against Bacillus subtilis and Aspergillus niger. CONCLUSIONS： The triterpenes： 2a, 2b, 3a, 3b, 3c and 3d were obtained from the stems, roots and leaves of E. hirta. Taraxerol （1） was only isolated from the stems, the leaves yielded phytol and phytyl fatty acid esters, while the roots afforded 4a-4d, linoleic acid, β-sitosterol, and squalene. Triterpene 1 and sample 2 were found to exhibit antimicrobial activities. Thus, these compounds are some of the active principles of E. hirta which is used in wound healing and the treatment of boils. The cytotoxic properties of sample 2 imply that triterpenes 2a and 2b contribute to the anticancer activity of E. hirta.     

Chromomoric acid derivatives from Tectona philippinensis

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tree, afforded four new chromomoric acid derivatives ( 1, 2, 3a, and 3b). Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. Antimicrobial testing was carried out on 1- 3 against a panel of bacteria and fungi.     

Excitability cycle of somatosensory evoked potentials during experimental alcoholization and withdrawal

It has been postulated that withdrawal from alcohol ingestion by alcoholics, is manifested by hyperexcitability of the central nervous system.In order to study changes in brain excitability in human alcoholics during intoxication and withdrawal, we used the recovery cycle of somatosensory evoked potentials. A recovery function was always determined in the morning (10 h after the last drink), during the three days of baseline, four days of alcoholization, and the four days subsequent to withdrawal from alcohol.Our results indicate a progressive increase of brain excitability starting with the intoxication period and reaching asymptote with the first day of total alcohol withdrawal. During the subsequent days of testing the recovery function decreases, approaching the level obtained during baseline determinations.Supported by Grant No. MH-16477 from the National Institute of Mental Health.