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.

Synthesis of hemslecin A derivatives: a new class of hepatitis B virus inhibitors.

A series of hemslecin A derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activities, namely, inhibiting the secretion of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and HBV DNA replication on HepG 2.2.15 cells. Most of the derivatives showed enhanced anti-HBV activities, of which compounds A1-A7, B5, C and E exhibited significant activities inhibiting HBV DNA replication with IC(50) values of 2.8-11.6 µM, comparable to that of the positive control, tenofovir. Compounds A1-A3, A5, B5, and C displayed low cytotoxicities, which resulted in high SI values of 89.7, 55.6, 77.8, >83.4, >55.8, and >150.5, respectively.

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

A series of caudatin derivatives were synthesized, and their anti-hepatitis B virus (HBV) activity was evaluated in HepG 2.2.15 cells. Most of the 3-O-substituted caudatin derivatives showed effective anti-HBV activity. Among the tested compounds, six compounds (2e-2h, 2l, 2r) exhibited significantly inhibitory activity against HBV DNA replication with IC(50) values in the range of 2.82-7.48 µM. Interestingly, two compounds (2e, 2f) had potent activity inhibiting not only the secretion of HBsAg (IC(50)=18.68 µM, 21.71 µM), HBeAg (IC(50)=13.16 µM, 33.73 µM), but also HBV DNA replication (IC(50)=7.48 µM, 3.63 µM). The structure-activity relationships (SARs) of caudatin derivatives had been discussed, which were useful for caudatin derivatives to be explored and developed as novel anti-HBV agents.

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.

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.

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).

Anti-HBV agents. Part 3: preliminary structure-activity relationships of tetra-acylalisol A derivatives as potent hepatitis B virus inhibitors.

Thirty-two tetra-acylated derivatives of alisol A were synthesized and evaluated for their anti-hepatitis B virus (HBV) activities and cytotoxicities in vitro. Among the series of alisol A derivatives examined, five analogues were active against HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) secretion in HepG 2.2.15 cells. These results also provide interesting structure-activity relationships of tetra-acylalisol A derivatives. Compounds tetra-acetyl alisol A (A1), tetra-methoxyacetyl alisol A (A23), and tetra-ethoxyacetyl alisol A (A24) exhibited high activities against secretion of HBsAg with IC(50) values of 0.0048, 0.0044, and 0.014 mM, respectively, HBeAg with IC(50) values of 0.011, 0.012, and 0.018 mM, respectively, and remarkable selective index values SI(HBsAg)>333, SI(HBeAg)>145; SI(HBsAg)=209, SI(HBeAg)=77; and SI(HBsAg)>200, SI(HBeAg)>156, respectively. Additional studies in rats showed that compound A1 has favorable pharmacokinetic prosperities for further development purpose, with elimination half-time (t(1/2)) of 1.63 h and oral bioavailability (F) of 40.9%.

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.

Structure-activity relationships study of 6-chloro-4-(2-chlorophenyl)-3-(2-hydroxyethyl) quinolin-2(1H)-one derivatives as novel non-nucleoside anti-hepatitis B virus agents.

A series of novel 6-chloro-4-(2-chlorophenyl)-3-(2-hydroxyethyl) quinolin-2(1H)-one derivatives were synthesized and evaluated for anti-hepatitis B virus (anti-HBV) activities in vitro to explore their structure-activity relationships (SARs). Most of the synthesized compounds possessed potent anti-HBV activity, of which the promising compound 44 exhibited significantly inhibitory potency against the secretion of hepatitis surface antigen (HBsAg) (IC(50) = 0.010 mM, SI > 135), hepatitis e antigen (HBeAg) (IC(50) = 0.026 mM, SI > 51) and the replication of HBV DNA (IC(50) = 0.045 mM). Preliminary mechanism study suggested compound 44 could mainly enhance the transcript activity of HBV ENI (enhancer I), EN-II (enhancer II).