ABSTRACT
The purpose of this study is to find out anti-HIV-1 reverse transcriptase (RT)/protease (PR) activity and inhibition of virus replication in cell cultures of novel coumarin analogs and determine their structure-activity relationship. Coumarin derivatives have been demonstrated to inhibit the activity of HIV-1 RT/PR in cell free system. It also shows inhibition effects to HIV-1 replication in cell culture. Based on the Chinese traditional pharmacological characteristics and protein three dimension computer aided design, analogs of tetracyclic dipyranocoumarin were synthesized from natural leading compounds. We studied the relationship of antiviral effects and chemical structures via HIV-1 PR/RT enzyme models and cell culture model system. Seven compounds were designed and tested. Several compounds showed anti-HIV-1 activity in varying degrees, especially V0201 showed much higher anti-HIV-1 activity with 3.56 and 0.78 micromol x L(-1) of IC50 against HIV-1 PR/RT and 0.036 micromol x L(-1) against HIV-1 replication in PBMC cultures. V0201 with a novel structure may be a new leading compound. These new compounds are valuable for development of new anti-HIV drugs in the future.
ABSTRACT
Cycloheximide (CHX) inhibits protein synthesis in most eukaryotic cells and it is a well-known tool commonly used in biochemical research. In this paper, the antiviral spectrum of CHX against several DNA and RNA viruses have been evaluated. CHX showed strong inhibitory activities against several RNA viruses such as HIV-1, influenza viruses, coxsackie B virus, enterovirus (EV71) and several DNA viruses such as HSV and HCMV. Especially the strong inhibitory activities of CHX against coxsackie B virus and enterovirus caught our attention, since effective drugs available in clinic are limited. The SAR of CHX derivatives also has been discussed in the paper. The hydroxyl group at C-2' and carbonyl group at C-2" of CHX are essential for its antiviral activity. And modification to these groups results its derivatives' antiviral activities reduced or lost.
ABSTRACT
An improved and practical synthesis of racemic 11-demethylcalanolide A [(±)-1] was developed. This improved process involved Pechmann reaction on phloroglucinol with ethyl butyrylacetate to give 5, 7,-dihydroxy-4-n-propylcoumarin(3). Poly phosphoric acid (PPA) catalyzed acylation of compound(3) with crotonic acid, then intramolecular cyclization was achieved simultaneously in one step to afford the key intermediate chromanone(4). A microwave assisted synthetic method preparing chromene(6) using chromenynation of chromanone(4) with 1, 1-diethoxy-methyl-2-butene was conducted. Luche reduction of chromene(6) using NaBH<,4> with CeCl3·7H2O preferably gave (±)-1. The overall yield of this four step synthesis of (±)-1 was around 32% increasing one fold more than that of the previous method. An in vitro investigation showed that (±)-1 exhibited inhibitory activities against both wild-type and drug-resistant HIV-1 in HIV-1 RT and cell culture assay, and significant synergistic effects in combination with AZT, T-20, and indinavir. Its LD50 of acute toxicity in mice by intragastric administration and by intraperitoneal injection were 735.65mg·kg-1 and 525.10mg·kg-1, respectively. The C<,max> and AUC<,0-∞> were 0.54μg·mL-1 and 1.08(μg·mL-1)·h, respectively. The dynamics study of the inhibition of mice sera on HIV-1 RT showed that mice treated with 100mg·kg-1 (±)-1 once intraperitoneally were similar to that of 5mg·kg-1 of known clinical effective anti-HIV-1 drug neverapine. The results suggested that further investigation of the anti-HIV candidate (±)-1 was warranted.
ABSTRACT
<p><b>BACKGROUND</b>To establish a SAH hydrolase antiviral screening in vitro model for screening of broad spectrum antiviral agents.</p><p><b>METHODS</b>SAH hydrolase was purified from rat livers by (NH4) 2SO4 fractionation, DEAE52,hydroxyapatite and Sephadex G-100 chromatography successively. The activity of SAH hydrolase was estimated by radio labeled substrate in synthesis direction by TLC.</p><p><b>RESULTS</b>Purified SAH hydrolase showed a single band in SDS-PAGE electrophoresis with silver nitrate staining, the apparent molecular weight is 45 000. The Km for adenosine is (6.32 +- 0.17) micromol/L. The IC50 of S-DNPA, a known inhibitor of SAH hydrolase, was 7.6 micromol/L estimated in our system. The structure and activity relationships shown by racemic and regiosomer analogs of S-DHPA indicated that the structural specificity of SAH hydrolase was high. 42 compounds had been screened in the system and no compound showed more inhibitory activity against SAH hydrolase than S-DNPA.</p><p><b>CONCLUSIONS</b>An in vitro antiviral screening model has been established using SAH hydrolase. It can also be used to study kinetics of enzyme inhibition.</p>