Tong Han

Antiproliferative activity and apoptosis inducing effects of nitric oxide donating derivatives of evodiamine

The first series of nitric oxide donating derivatives of evodiamine were designed and prepared. NO releasing ability of all target derivatives was evaluated in BGC-823, Bel-7402 and L-02 cells. The cytotoxicity was evaluated against three human tumor cell lines (Bel-7402, A549 and BGC-823) and normal human liver cells L-02. The nitrate derivatives 11a and 11b only exhibited moderate activity and furoxan-based derivatives 13a-c, 14a and 14b showed promising activity. 13c showed good cytotoxic selectivity between tumor and normal liver cells and was further investigated for its apoptotic properties on human hepatocarcinoma Bel-7402 cells. The molecular mode of action revealed that 13c caused cell-cycle arrest at S phase and induced apoptosis in Bel-7402 cells through mitochondria-related caspase-dependent pathways.

New naphthopyrones from marine-derived fungus Aspergillus niger 2HL-M-8 and their in vitro antiproliferative activity

A new cytotoxic dimeric naphthopyrone, aurasperone H (1), together with eight related known polyketides (2–9) was isolated from a marine-derived fungus Aspergillus niger 2HL-M-8. The structure of new compound 1 was elucidated on the basis of its spectroscopic data (1D, 2D NMR and CD). Compound 1 exhibited moderate inhibitory activity against the human lung adenocarcinoma A549 and the human leukaemia HL-60 cell lines. Compound 5 displayed significant in vitro antiproliferative activity against HL-60 cell line with an IC50 value of 0.8 μM.

Racemic alkaloids from Macleaya cordata: structural elucidation, chiral resolution, and cytotoxic, antibacterial activities

Three pairs of new enantiomeric natural alkaloids (±)-macleayins C–E (1–3), together with five pairs of known racemic alkaloids (4–8), were isolated from the aerial parts of Macleaya cordata. Compounds 1–5 were separated successfully by chiral-phase HPLC to yield optically pure isomers. However, chiral resolution of compounds 6–8 existing as racemers in the plant was unsuccessful. It is noteworthy that, macleayin C represents a novel type of hybrid composed of a dihydrobenzophenanthridine alkaloid and a phenylpropanoid. The structures including the absolute configurations of (±)-1–5 were established by detailed spectroscopic analyses and electronic circular dichroism calculations. All the isolates were evaluated for in vitro anti-tumor and antibacterial activities, and compounds (±)-4–5 exhibited potent cytotoxicity against HL-60 cell lines with IC50 values less than 3.0 μM, and compounds (±)-1–3 showed moderate cytotoxic activity. Only compound 7 revealed inhibitory activities against Staphylococcus aureus, Bacillus subtilis, and Candida albicans with MIC values of 33.07, 8.27, and 8.27 μg mL−1, respectively.

Oridonin, a Promising ent-Kaurane Diterpenoid Lead Compound

Oridonin belongs to ent-kaurane tetracyclic diterpenoid and was first isolated from Isodon species. It exhibits inhibitory activities against a variety of tumor cells, and pharmacological study shows that oridonin could inhibit cell proliferation, DNA, RNA and protein synthesis of cancer cells, induce apoptosis and exhibit an antimutagenic effect. In addition, the large amount of the commercially-available supply is also very important for the natural lead oridonin. Moreover, the good stability, suitable molecular weight and drug-like property guarantee its further generation of a natural-like compound library. Oridonin has become the hot molecule in recent years, and from the year 2010, more than 200 publications can be found. In this review, we summarize the synthetic medicinal chemistry work of oridonin from the first publication 40 years ago and share our research experience of oridonin for about 10 years, which may provide useful information to those who are interested in this research field.

Synthesis, Biological Activity, and Apoptotic Properties of NO-Donor/Enmein-Type ent-Kauranoid Hybrids

Herein, we reported on a series of synthetic nitric oxide-releasing enmein-type diterpenoid hybrids (9a–i). All the target compounds showed potent antibacterial activity against selected Gram-positive bacteria S. aureus and B. subtilis. The antiproliferative activity against human tumor K562, MGC-803, CaEs-17 and Bel-7402 cells, and human normal liver cells L-02 was tested and the structure activity relationships (SARs) were also concluded. Compounds 9b and 9d showed the best activity against S. aureus and B. subtilis with the same minimal inhibitory concentrations (MICs) of 4 and 2 μg/mL, respectively. The derivative 9f displayed IC50 values of 1.68, 1.11, 3.60 and 0.72 μM against the four cancer cell lines above and 18.80 μM against normal liver cells L-02; meanwhile, 9f also released a high level of NO at the time point of 60 min of 22.24 μmol/L. Furthermore, it was also found that 9f induced apoptosis via the mitochondria-related pathway and arrested cell cycle of Bel-7402 cells at S phase. These findings might be important to explore new chemical entities for the main causes of in-hospital mortality of S. aureus infection, combined with a solid tumor.

Antitumor and Antibacterial Derivatives of Oridonin: A Main Composition of Dong-Ling-Cao

Isodon rubescens has been used as a traditional green tea for more than 1000 years and many medicinal functions of I. rubescens are also very useful, such as its well-known antitumor and antibacterial activities. Oridonin, a bioactive ent-kaurane diterpenoid, is the major ingredient of this medicinal tea. Herein, 22 novel oridonin derivatives were designed and synthesized. The antibacterial activity was evaluated for the first time. Compound 12 was the most promising one with MIC of 2.0 μg/mL against B. subtilis, which was nearly 3-fold stronger than positive control chloromycetin. The antiproliferative property was also assayed and compound 19 showed stronger activity than taxol. The apoptosis-inducing ability, cell cycle arrest effect at S phase and influence of mitochondrial membrane potential by 19 in CaEs-17 cancer cells were first disclosed. Based on the above results, the cell apoptosis induced by compound 19 in CaEs-17 cells was most probably involved in the intrinsic apoptotic pathway.

Design and synthesis of novel nitrogen mustard-evodiamine hybrids with selective antiproliferative activity

A series of novel nitrogen mustard-evodiamine hybrids were synthesized and evaluated for their antitproliferative properties. The antiproliferative activities of 10a-d, 11a-d, and 12a-d against four different kinds of human cancer cell lines (PC-3, HepG2, THP-1 and HL-60) and human normal peripheral blood mononuclear cells (PBMC) were determined. The results showed that all the target hybrid compounds exhibited antiproliferative activities against tested human tumor cell lines to some extent and no antiproliferative activities (>200 μM) against human normal PBMC cells. The antiproliferative selectivity between tumorous and normal cells was very useful for further antitumor drug development. Among the target compounds, 12c showed the strongest cytotoxicity against two tumor cell lines (THP-1 and HL-60) with IC50 values of 4.05 μM and 0.50 μM, respectively, and selected for further mechanism study in HL-60 cells. The results showed that 12c could induce HL-60 cells apoptosis and arrest at G2 phase at low sub-micromolar concentrations via mitochondria-related pathways.

New chalcone and pterocarpoid derivatives from the roots of Flemingia philippinensis with antiproliferative activity and apoptosis-inducing property

Investigation of the roots of Flemingia philippinensis resulted in the isolation of two new chalcones, flemiphilippinones B (1) and C (2), and one new pterocarpoid, demethylwedelolactone-11-methyl ether (3), together with 12 known compounds (4-15). The antiproliferative activity against PC-3 cells was evaluated and most compounds showed cytotoxicity, among which, compound 2 exhibited GI50 value of 14.12μM. The antiproliferative activity of 2 against Bel-7402 and CaEs-17 cells was also measured, with GI50 values of 1.91 and 2.58μM, respectively. Intensive mechanism study showed that 2 caused cell-cycle arrest at S/G2 phase and induced apoptosis in Bel-7402 cells through mitochondria-related pathway.

Novel nitric oxide-releasing spirolactone-type diterpenoid derivatives with in vitro synergistic anticancer activity as apoptosis inducer.

Herein, we reported the cytotoxicity, NO-releasing property, and apoptosis induced ability of two series of novel nitric oxide-releasing spirolactone-type diterpenoid derivatives (10a-f and 15a-f). All the title compounds were more potent than oridonin (7) and parent compound (9 or 14) against human tumor Bel-7402, K562, MGC-803 and CaEs-17 cells. SARs were concluded based on above data. Compound 15d exhibited the strongest antiproliferative activity with the IC50 of 0.86, 1.74, 1.16 and 3.75μM, respectively, and could produce high level (above 25μM) of NO at the time point of 60min. Further mechanism evaluation showed that 15d could induce S phase cell cycle arrest and apoptosis at low micromolar concentrations in Bel-7402 cells via mitochondria-related pathways. It was expected that the remarkable biological profile of the synthetic NO-releasing spirolactone-type diterpenoid analogs make them possible as promising candidates for the development of anticancer agents.

Novel hybrids of brefeldin A and nitrogen mustards with improved antiproliferative selectivity: Design, synthesis and antitumor biological evaluation

A series of novel conjugates of brefeldin A (11a-c, 12a-c and 13a-c) were obtained by introducing a variety of nitrogen mustards at 4-OH or 7-OH position to explore more efficacious and less toxic antitumor agents. The antiproliferative activities were tested against three cancer cell lines (HL-60, PC-3 and Bel-7402) and one multidrug resistant cell line Bel-7402/5-FU. Among them, compound 11a was the strongest derivative with IC50 values of 4.48, 9.37, 0.2 and 0.84 μM, respectively, and more potent than nitrogen mustards. Though the antiproliferative potency was weaker than the lead compound brefeldin A, 11a displayed lower toxicity than brefeldin A (IC50 < 0.001 μM) with an IC50 of 9.74 μM against normal human liver L-O2 cells, showing good selectivity between normal and malignant liver cells. The mechanism studies confirmed that 11a could induce apoptosis, arrest cell cycle at the G1 phase and lead to mitochondrial dysfunction in Bel-7402 cells at submicromolar concentrations. Furthermore, 11a induced the intrinsic apoptotic mitochondrial pathway in Bel-7402 cells, evidenced by the enhanced expression of the pro-apoptotic protein Bax, cyto-c and p53, and the reduced expression of the anti-apoptotic protein Bcl-2. The caspase-9 and -3 levels were also up-regulated.