Chang-An Geng

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.

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.

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.

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.

LC-MS Guided Isolation of (+/-)-Sweriledugenin A, a Pair of Enantiomeric Lactones, from Swertia leducii

(±)-Sweriledugenin A, a pair of novel enantiomeric lactones, were isolated from Swertia leducii under the guidance of LC-MS investigation. The enantiomeric separation was achieved by HPLC on a chiral column. Their structures were determined by extensive NMR spectra, X-ray, and quantum calculations. (+)-Sweriledugenin A and (-)-sweriledugenin A showed activities inhibiting HBV DNA replication with the IC50 values of 36.86 and 26.55 μM on the HepG 2.2.15 cell line in vitro.

Small-Molecule Inhibitors for the Treatment of Hepatitis B Virus Documented in Patents

Hepatitis B virus (HBV) infection is a serious health problem worldwide, and the current treatment methods including vaccines, immunomodulators, interferons and nucleoside analogs are far from satisfactory. For the search of new anti-HBV agents, much investigation has revealed a large number of small-molecule compounds with various skeletons and promising anti-HBV activities. Although some reviews on anti-HBV progress have been published, they are mainly concentrated on the results reported in journal articles. This review provides an overview of the structural features and anti-HBV properties of the small-molecule anti-HBV inhibitors claimed in recent patents (from 2001 to 2010). These small-molecules can be structurally classified as two main types, nucleoside analogs (cyclic and acyclic nucleosides) and non-nucleosides (natural and synthesized compounds), which are declared with the activity inhibiting the secretion of HBsAg and HBeAg and HBV DNA replication in vitro, as well as anti-DHBV DNA in vivo. Especially, the non-nucleosides with diverse skeletons and novel mechanism offer prolific candidates for anti-HBV drug discovery, which are preferred to be used as adjuvant therapy for HBV infection. This paper will provide valuable information for understanding the current anti-HBV investigation and developing new anti-HBV agents.

Synthesis and biological assay of 4-aryl-6-chloro-quinoline derivatives as novel non-nucleoside anti-HBV agents

A series of 4-aryl-6-chloro-quinoline derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activities, namely the abilities to inhibit the secretion of HBV surface antigen (HBsAg), HBV e antigen (HBeAg), and replication of HBV DNA in HepG 2.2.15 cells. Most of the compounds exhibited moderate inhibitory activity against the secretion of HBsAg and HBeAg. Nine compounds (3, 5, 6, 7, 10, 14, 17, 20, 24) showed significant inhibition against HBV DNA replication with IC(50) values in the range of 4.4-9.8 μM, which were comparative to that of positive control tenofovir. Of them, compounds 10, 17, and 20 had low cytotoxicities, resulting in high SI values, >551.2, >143.7, and >284.5, respectively.

Polyacetylenes and anti-hepatitis B virus active constituents from Artemisia capillaris

Three new polyacetylenes, 8-(Z)-decene-4, 6-diyne-1, 3, 10-triol (1), 1, 3S, 8S-trihydroxydec-9-en-4, 6-yne (2), 3S, 8S-dihydroxydec-9-en-4, 6-yne 1-O-β-D-glucopyranoside (3), and one new glucosyl caffeoate, 1-O-ethyl-6-O-caffeoyl-β-D-glucopyranose (4), together with 34 known compounds were isolated from Artemisia capillaris. The structures of the new compounds were determined by extensive spectroscopic analyses including 1D and 2D NMR, HRESIMS, [α]D and CD experiments. Among them, 19 compounds showed activity inhibiting HBsAg secretion; 20 compounds showed activity inhibiting HBeAg secretion; and 25 compounds possessed inhibitory activity against HBV DNA replication according to our anti-HBV assay on HepG 2.2.15 cell line in vitro. The most active compound 12 could inhibit not only the secretions of HBsAg and HBeAg, but also HBV DNA replication with IC50 values of 15.02 μM (SI=111.3), 9.00 μM (SI=185.9) and 12.01 μM (SI=139.2).

Three new secoiridoids, swermacrolactones A–C and anti-hepatitis B virus activity from Swertia macrosperma

Three new secoiridoids, swermacrolactones A-C (1-3), together with fourteen known compounds were isolated from Swertia macrosperma. Their structures were elucidated based on extensive spectroscopic analyses (IR, UV, MS, 1D and 2D NMR). By anti-HBV assay on the Hep G 2.2.15 cell line in vitro, the most active compound, luteolin (9), inhibited the secretion of hepatitis B virus surface antigen (HBsAg) and hepatitis B virus e antigen (HBeAg) with IC50 values of 0.02 and 0.02 mM, respectively.