The influence of intracellular keratin 8 on hepatitis C virus replication / 药学学报

The level of intracellular keratin 8(KRT-8) is associated with liver diseases, whose expression is increased in hepatitis C virus (HCV)-infected patients with hepatocarcinoma and in cultural cells infected with HCV. However, it is not clear whether KRT-8 will impact HCV replication. In this paper, the HCV replication was analyzed in response to high expression and silence of KRT-8. The inhibitory activities against wild-type and mutant HCV were also analyzed by silence of KRT-8 or combined with known anti-HCV drug telaprevir. Results showed that the protein level of KRT-8 was increased in proportion with the HCV replication. The high expression was found to facilitate HCV replication, while the silence of KRT-8 was able to inhibit HCV replication and enhanced the anti-HCV activity of telaprevir. It also inhibited A156T and D168V mutant HCV, which are resistant to protease inhibitors. These results suggest that KRT-8 is a co-factor for HCV replication. Down-regulation of KRT-8 can inhibit wild type and mutant HCV replication to enhance the anti-HCV activity of known anti-HCV drugs. Therefore, KRT-8 may be a new target in the development of anti-HCV agents.

Recent advances in the study of mechanism of APOBEC3G against virus / 药学学报

APOBEC3 is a class of cytidine deaminase, which is considered as a new member of the innate immune system, and APOBEC3G belongs to this family. The research about APOBEC3G is a new direction of innate immune defense mechanism against virus. APOBEC3G has the restrictive activity on many viral replications, which deaminates dC to dU in the viral genome and then induces extensive hypermutation. APOBEC3G can also interrupt viral replication at several phases such as reverse transcription, replication, nucleocapsid and so on by non-deamination mechanisms. However, virus can encode viral proteins to counteract the restriction activity of APOBEC3G. Elucidation of the antagonistic interaction between APOBEC3G and the virus will be contributed to development of new antiviral drugs in the future.

Inhibition of the replication of HIV-1 by norcantharidin in vitro / 药学学报

For obtaining new structural compounds with unique resistance profiles or novel mechanisms of action on HIV-1 from natural products, anti-HIV-1 drug screening models were used in vitro. Norcantharidin (NCTD), a derivative from cantharidin, was found to have inhibitory activities on HIV-1(IIIB) p24 antigen in lymphocyte lines MT-4, CEM and H9. It inhibited HIV-1 strain 018a (sensitive to zidovudine) from replicating with EC50 (50% effective concentration) of 14.9 micromol L(-1) and also inhibited HIV-1 strain 018c (resistant to zidovudine) from replicating with EC50 of 20.2 micromol L(-1) in primary lymphocytes peripheral blood mononuclear cells (PBMC). Norcantharidin showed synergistic activity with zidovudine on HIV-1(IIIB) in MT-4 cells, the combination index was less than 0.3. But, it was not active on HIV-1 integrase, reverse transcriptase or protease in vitro. As the structure of norcantharidin is unique and different from that of all clinic drugs approved, it would be possible to obtain new and effective compounds against HIV-1 with low toxicities after modification of norcantharidin.

Effective components against HIV-1 replicative enzymes isolated from plants / 药学学报

Plant active components characterized of many different structures and activities on multiple targets, have made them to be the important sources of inhibitors on HIV-1. For finding leading compounds with new structure against HIV-1, three key HIV-1 replicative enzymes (reverse transcriptase, protease and integrase) were used as screening models. The in vitro activities of 45 plant derived components isolated from Schisandraceae, Rutaceae and Ranunculaceae were reported. Within twelve triterpene components isolated, eight compounds were found to inhibit HIV-1 protease, in these eight active compounds, kadsuranic acid A (7) and nigranoic acid (8), inhibited both HIV-1 protease and integrase; Among fifteen lignans, meso-dihydroguaiaretic acid (15) and kadsurarin (16) were active on HIV-1 reverse transcriptase, and 4, 4-di(4-hydroxy-3-methoxyphenly)-2, 3-dimethylbutanol (13) active on HIV-1 integrase. All of the six alkaloids, seven flavones, and five others compounds were not active or only with low activities against HIV-1 replicative enzymes. Further studies of the triterpene components showing strong inhibitory activities on HIV-1 were warranted.

Study on anti-HIV-1 activities of composite extract from salvia yunnanensis / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore and evaluate the activities of composite extract from Salvia Yunnanensis and in cell cultures (DS-MEF) for inhibition of human immuno-deficiency virus type 1 (HIV-1) in vitro and in cell cultures.</p><p><b>METHODS</b>The inhibitory activity of DS-MEF on HIV-1 reverse transcriptase (RT), protease (PR) and integrase (IN) were detected in vitro with radionuclide 3H incorporation, fluorescence assay and enzyme-linked immunosorbent assay respectively. The human T-lymphocyte MT-4 cell line, human T-lymphocyte H 9 cell line chronically infected with HIV-1 IIIB, and the fresh peripheral blood mononuclear cell (PBMC) of healthy persons as well as the laboratory passed HIV-1 IIIB and the clinically isolated HIV-1 AZT sensitive 018a or resistant 018c infected cell cultures were used for evaluating the cytotoxicities and inhibitory activities of DS-MEF on HIV-1 P 24 antigen. The acute toxicities of DS-MEF on KM mice were determined by gastric gavages and intraperitoneal injections with various dosages.</p><p><b>RESULTS</b>The IC50 of DS-MEF for inhibiting HIV-1 IN, RT and PR were 2.59 +/- 0.50 mg/L, 27.39 +/- 11.18 mg/L and 9.38 +/- 2.45 mg/L respectively. In MT-4 cell cultures infected with HIV-1 III, TC50 were 13.19 +/- 6.07 mg/L, IC50 and SI of anti-HIV-1 activity were 0.224 +/- 0.163 mg/L and 58.7; in chronically infected H 9 cell cultures, TC50 were 18.11 +/- 9.84 mg/L, IC50 on HIV-1 P 24 antigen and SI were l7.230 +/- 21.114 mg/L and 1.1 respectively; TC50 in HIV-1 infected PBMC cultures were 288.70 +/- 0.08 mg/L; IC50 on AZT sensitive HIV-1 018a: 26.42 +/- 11.16 mg/L, and SI: 10.9; On AZT resistant HIV-1 018c, IC50: 27.87 +/-5.35 mg/L, and SI: 10.4. Moreover, DS-MEF showed synergistic effect with AZT or nevirapine (NVP) on HIV-1 IIIB in MT-4 cell cultures, the respective combination index was 0.78 or 0.67. DS-MEF showed no acute toxicity in KM mice with the dosage up to 20 g/kg via gastrogavage, and the 50% lethal dose (LD50) via intraperitoneal injection was 1.18 g/kg.</p><p><b>CONCLUSION</b>DS-MEF is a promising anti- HIV-1 agent with low toxicity in mice and possesses multi-targets and effective activities.</p>

Anti-HIV activities of HIV-1 reverse transcriptase inhibitor racemic 11-demethyl-calanolide A / 药学学报

To compare the anti-HIV-1 activities of (+/-)-11-demethyl-calanolide A and its mother compound (+/-)-calanolide A in vitro and in vivo, the inhibitory activities of the two compounds on HIV-1 reverse transcriptase (RT) were detected in vitro with isotope 3H assay. The cytotoxicity and inhibition of cytopathic effect (CPE) were studied in HIV-1 IIIB infected MT-4 cell cultures by MTT staining method; Mice were given with the two compounds 100 mg x kg(-1) once intraperitoneally, then the mouse sera taken on 30 min and 60 min after administration were detected for the inhibition of HIV-1 RT in vitro. The data showed that (+/-)-11-demethyl-calanolide A and (+/-)-calanolide A inhibited HIV-1 RT in vitro with 50% inhibitory concentration (IC50) of (3.028 +/- 2.514) micromol x L(-1) and (3.965 +/- 5.235) micromol x L(-1), and also inhibited CPE in HIV-1 IIIB infected MT-4 cell cultures with IC50 of (1.081 +/- 0.337) micromol x L(-1) and (1.297 +/- 0.076) micromol x L(-1), respectively. After intraperitoneal injection of 100 mg x kg(-1) of the two compounds in mice, all the mice sera taken 30 and 60 min afterward inhibited HIV-1 RT in vitro. In comparison with control mice sera, the inhibitory rates of the sera for (+/-)-11 -demethyl-calanolide A were (42.7 +/- 1.5)% at 30 min (P < 0.01) and (32.2 +/- 6.1)% at 60 min (P < 0.05), separately, while the inhibitory rates of the sera for (+/-)-calanolide A were (40.7 +/- 6.3)% at 30 min (P < 0.01) and (29.2 +/- 6.7)% at 60 min. The results suggested that (+/-)-11-demethyl-calanolide A is a new non-nucleoside HIV-1 RT inhibitor, its anti-HIV-1 activities in vitro, in cell cultures and in mice were slightly higher than that of its mother compound (+/-)-calanolide A and warrants further studies.

Anti-HIV activities of Achyranthes bidentata polysaccharide sulfate in vitro and in vivo / 药学学报

Achyranthes bidentata polysaccharide sulfate (ABPS) was a sulfated derivate derived from Achyranthes bidentata polysaccharide (ABP) which was isolated and identified from Chinese herb Achyranthes bidentata. The anti human immunodeficiency virus type 1 (HIV-1) activities were studied in vitro and in vivo. ABPS was found to inhibit HIV-1 reverse transcriptase and integrase with the 50% inhibiting concentration (IC60) of (2.948 +/- 0.556) micromol x L(-1) and (0.155 +/- 0.030) micromol x L(-1), respectively, but the parent compound ABP was not effective. ABPS inhibited HIV-1 P24 antigen with IC50 of (0.082 +/- 0.044) micromol x L(-1) and selective index (SI) of > (358 +/- 148) in MT-4 cell cultures acutely infected with HIV-1 IIIB virus, and with IC50 of (11.80 +/- 5.90) micromol x L(-1) and SI of > (24.2 +/- 12.1) in PBMC cell cultures acutely infected with clinical isolated zidovudine resistant HIV-1 virus, but there was no activity even at its concentration of 500 micromol x L(-1) in latent infection of H9/HIV-1 IIIB cell cultures. 5% sera taken from rats after intraperitoneal injection from rats with ABPS 125 mg x kg(-1) once or mice with 3 mg x kg(-1) qd for 20 days effectively inhibited HIV-1 P24 in MT-4 cell cultures, but those had no inhibitory effect when given orally. The results suggested that ABPS is a promising HIV-1 inhibitor, active on HIV-1 reverse transcriptase, integrase in vitro and HIV-1 P24 antigens in cell cultures, it was well absorbed by intraperitoneal injection but poor in oral bioavailability. It warrants further study.

Improved synthesis and pharmacological evaluation of racemic 11 -demethylcalanolide A / 药学学报

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,-dihydroxy4-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 NaBH4 with CeCl3 x 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 735.65 mg kg(-1) and 525.10 mg x kg(-1), respectively. The Cmax and AUC(0-infinity) were 0.54 microg x mL(-1) and 1.08 (microg x mL(-1) x h, respectively. The dynamics study of the inhibition of mice sera on HIV-1 RT showed that mice treated with 100 mg x kg(-1 (+/-)-1 once intraperitoneally were similar to that of 5 mg x 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.