Xue-Mei Zhang

Anti-HIV-1 activities of compounds isolated from the medicinal plant Rhus chinensis.

AIM OF THE STUDY Previously, we reported that the petroleum ether fraction, RC-1, and EtOAc fraction, RC-2, of the medicinal plant Rhus chinensis showed potent anti-HIV-1 activities. To address anti-HIV-1 constituents of RC-1 and RC-2, 17 compounds were isolated. Anti-HIV-1 activities and possible action mechanisms of these compounds were investigated. METHODS The syncytial formation induced by HIV-1 was determined under the inverted microscope, cellular toxicity and protection assay were assessed by MTT method, reduction of p24 antigen expression level and RT activity were measured by ELISA, and inhibition of recombinant HIV-1 PR was monitored by the fluorescent signal. RESULTS The compounds 1 and 13 inhibited HIV-1-induced syncytium formation potently with TI value of 42.31 and 19.07, respectively. Compounds 4, 5, 6, 9 and 10 were less potent with TI value of 8.94, 8.22, 4.14, 5.11 and 5.34, respectively. Compound 1, a benzofuranone-type compound, previously reported as a novel anti-HIV-1 agent, might target late-steps of HIV-1 life cycle. Compound 13 inhibited HIV-1 replication with EC(50) of 7.16mug/ml and might target at/before integration step. CONCLUSION These compounds might contribute to anti-HIV-1 activities extracts of the medicinal plant Rhus chinensis.

Synthesis and in vitro anti-hepatitis B virus activities of 4-aryl-6-chloro-quinolin-2-one and 5-aryl-7-chloro-1,4-benzodiazepine derivatives.

A series of 4-aryl-6-chloro-quinolin-2-ones and 5-aryl-7-chloro-1,4-benzodiazepine were synthesized and assayed for their in vitro anti-hepatitis B virus activities and cytotoxicities for the first time. Some of the tested compounds were active against HBsAg and HBeAg secretion in Hep G2.2.15 cells. Compound 5c showed IC(50) of 0.074 and 0.449 mM on HBsAg and HBeAg secretions, respectively, which were 10 times higher than that of its analog 4c and led to better selective index (SI) values (SI=23.2 and 3.4, respectively).

Anti‐Hepatitis B Virus Active Lactones from the Traditional Chinese Herb: Swertia mileensis

Swerilactones H-K (1-4), which are four novel lactones with an unprecedented C29 skeleton, were isolated from Swertia mileensis (Qing-Ye-Dan), an endemic Chinese herb used for treating viral hepatitis. Their structures were determined by extensive spectroscopic and X-ray crystallographic diffraction analyses. Swerilactones H-K exhibit potent anti-hepatitis B virus activity against HBV DNA replication with IC(50) values ranging from 1.53 to 5.34 μM. For the first time, a plausible biogenetic pathway for swerilactones H-K, together with the previously reported swerilactones A-D is proposed. From a biogenetic point of view, swerilactones A-D are ascribed as secoiridoid dimers, and swerilactones H-K as secoiridoid trimers.

1-Aryl-tetrahydroisoquinoline analogs as active anti-HIV agents in vitro

A series of 1-aryl-6,7-dihydroxyl(methoxy)-1,2,3,4-tetrahydroisoquinolines (compounds 1-36) were synthesized via Pictet-Spengler cyclization. All the synthesized compounds were assayed for activities against HIV-1(IIIB) in C8166 cell cultures by MTT method for the first time. The results of the anti-HIV screening revealed that 6,7-dihydroxytetrahydroisoquinolines possessed higher selective index than 6,7-dimethoxyl analogs due to the significantly decreased cytotoxicities. Compounds 6, 24, and 36 showed potent anti-HIV activities with EC(50) values of 8.2, 4.6, and 5.3microM respectively, and the cytotoxicities (CC(50)) of these three compounds were 784.3, 727.3, and 687.3microM, which resulted in SI values larger than 95, 159, and 130 respectively.

Swerilactones A and B, Anti-HBV New Lactones from a Tradtional Chinese Herb: Swertia mileensis as a Treatment for Viral Hepatitis

Swerilactones A (1) and B (2), two novel lactones with an unprecedented 6/6/6/6/6 pentacyclic ring system, were isolated from the traditional Chinese herb of Swertia mileensis with activity against the hepatitis virus. Their structures and relative stereochemistry were elucidated based on spectroscopic methods and further confirmed by X-ray single crystal diffraction analysis. In vitro antihepatitis B virus (HBV) assay on Hep G 2.2.15 cell line showed that compound 1 inhibited HBsAg and HBeAg secretion with IC(50) values of 3.66 and 3.58 mM, respectively.

Anti-HBV agents. Part 1: Synthesis of alisol A derivatives: A new class of hepatitis B virus inhibitors

A series of alisol A derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activities and cytotoxicities in vitro. The preliminary investigation demonstrates that simple modifications of the parent structure of alisol A can produce a number of potentially important derivatives against HBV. The most active anti-HBV compound 6a showed high activities against the secretion of HBV surface antigen (IC(50)=0.024 mM), HBV e antigen (IC(50)=0.028 mM) and remarkable selective indices (SI(HBsAg)>108, SI(HBeAg)>93), which was selected for further evaluation as a novel HBV inhibitor.

Synthesis, structure-activity relationships and biological evaluation of dehydroandrographolide and andrographolide derivatives as novel anti-hepatitis B virus agents

Dehydroandrographolide and andrographolide, two natural diterpenoids isolated from Andrographis paniculata possessed activity against HBV DNA replication with IC50 values of 22.58 and 54.07μM and low SI values of 8.7 and 3.7 in our random assay. Consequently, 48 derivatives of dehydroandrographolide and andrographolide were synthesized and evaluated for their anti-HBV properties to yield a series of active derivatives with lower cytotoxicity, including 14 derivatives against HBsAg secretion, 19 derivatives against HBeAg secretion and 38 derivatives against HBV DNA replication. Interestingly, compound 4e could inhibit not only HBsAg and HBeAg secretions but also HBV DNA replication with SI values of 20.3, 125.0 and 104.9. Furthermore, the most active compound 2c with SI value higher than 165.1 inhibiting HBV DNA replication was revealed with the optimal logP value of 1.78 and logD values. Structure-activity relationships (SARs) of the derivatives were disclosed for guiding the future research toward the discovery of new anti-HBV drugs.

UFLC/MS-IT-TOF guided isolation of anti-HBV active chlorogenic acid analogues from Artemisia capillaris as a traditional Chinese herb for the treatment of hepatitis.

ETHNOPHARMACOLOGICAL RELEVANCE Hepatitis B induced by HBV is a serious health problem. Artemisia capillaris (Yin-Chen) has long been used to treat hepatitis in traditional Chinese medicine. Coumarins, flavonoids and organic acids were revealed as its hepatoprotective and choleretic components, but its anti-HBV active components remain unknown. This current study focused on its anti-HBV active constituents by various chromatographic methods. MATERIAL AND METHODS LC/MS and bioassay-guided fractionation on the active extract of Artemisia capillaris led to the isolation of nine chlorogenic acid analogues. Structures of the isolates were elucidated by MS/MS and NMR techniques. Anti-HBV assay was performed on HepG 2.2.15 cell line in vitro: reduction of HBsAg and HBeAg secretions was measured by an ELISA method; inhibition of HBV DNA replication was monitored by real-time quantitative PCR and cellular toxicity was assessed by a MTT method. RESULTS The 90% ethanol extract of Artemisia capillaris (Fr. AC) showed significantly inhibitory activity on HBV DNA replication with an IC₅₀ value of 76.1 ± 3.9 μg/mL and low cytotoxic effects (SI>20.1). To clarify its active constituents, the extract was further separated into 3 sub-fractions (AC-1, AC-2 and AC-3), of which Fr. AC-2 was the most active fraction against HBeAg secretion and HBV DNA replication with IC50 values of 44.2 ± 2.8 and 23.2 ± 1.9 μg/mL. Nine chlorogenic acid analogues were detected from the active part (Fr. AC-2) by a LC/MS technique and further separated by a HPLC method. The isolates were determined as chlorogenic acid (1), cryptochlorogenic acid (2), neochlorogenic acid (3), 3,5-dicaffeoylquinic acid (4), 4,5-dicaffeoylquinic acid (5), 3,4-dicaffeoylquinic acid (6), chlorogenic acid methyl ester (7), cryptochlorogenic acid methyl ester (8), neochlorogenic acid methyl ester (9). Compounds 1-6 possessed potent activity against HBV DNA replication with IC50 values in the range of 5.5 ± 0.9-13.7 ± 1.3 μM. Di-caffeoyl analogues (4-6) also exhibited activity against the secretions of HBsAg and HBeAg. Esterified analogues (7-9) showed dramatically decreased anti-HBV activity, indicating that carboxyl group is closely associated to the anti-HBV activity. CONCLUSIONS This investigation was focused on the active fractions of Artemisia capillaris and their active compositions, which showed that Fr. AC-2 was the main active section of Artemisia capillaris and chlorogenic acid analogues were the main constituents contributing to its anti-HBV activity. These results support the ethnopharmacological use of Artemisia capillaris as anti-HBV agents.

Anti-HBV agents. Part 2: synthesis and in vitro anti-hepatitis B virus activities of alisol A derivatives.

Chemical modifications were performed on hydroxyl groups at C-11,23,24,25 positions and C-13(17) double bond of alisol A for structure-activity relationship study. Forty-one derivatives of alisol A were synthesized and assayed for their in vitro anti-hepatitis B virus (HBV) activities and cytotoxicities. Of them, 14 compounds were active against HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) secretion in HepG 2.2.15 cells, and the most promising compound 25 exhibited high activities against secretion of HBsAg (IC(50)=0.028 mM), HBeAg (IC(50)=0.027 mM) and remarkable selective indices (SI(HBsAg) >90, SI(HBeAg) >93).

Mulberrofuran G and isomulberrofuran G from Morus alba L.: anti-hepatitis B virus activity and mass spectrometric fragmentation.

Mulberrofuran G (1) and isomulberrofuran G (2), a pair of isomeric Diels-Alder-type adducts, were isolated from the root bark of Morus alba L. Isomulberrofuran G (2) as a new IIB-type Diels-Alder-type adduct, was elucidated by extensive (1)H, (13)C, and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) spectroscopic analyses. A fragmentation study on compounds 1 and 2 was performed by high-resolution electrospray ionization (ESI) multistage tandem mass spectrometry linked with ion-trap (IT) and time-of-flight (TOF) mass analyzers (ESI-MS(n)/IT-TOF) in negative mode, which resulted in obviously different fragmentations. In the MS(2) experiments, the characteristic ions at m/z 451 and 439 could be revealed as their respective diagnostic ions. Mulberrofuran G (1) showed moderate activity, inhibiting hepatitis B virus (HBV) DNA replication with the IC(50) value of 3.99 μM, according to the anti-HBV assay on the HepG 2.2.15 cell line in vitro.