Jiang-Jiang Tang

Semisynthesis and in vitro cytotoxic evaluation of new analogues of 1-O-acetylbritannilactone, a sesquiterpene from Inula britannica

Semisynthetic analogues of the natural product 1-O-acetylbritannilactone (ABL), a sesquiterpene isolated from the medicinal plant Inula britannica, have been prepared and exhibited significant in vitro cytotoxic activities against four cell lines including three human cancer cell lines (HCT116, HEp-2 and HeLa) and one normal hamster cell line (CHO). Structure-activity relationships indicate that esterification of 6-OH (enhanced lipophilicity) and α-methylene-γ-lactone functionalities play important roles in conferring cytotoxicity. Among the tested compounds, 14 bearing a lauroyl group (12C) at the 6-OH position displayed most potent in vitro cytotoxic activity, with IC50 values between 2.91 and 6.78 μM, comparable to the positive control etoposide (VP-16, IC50 values between 2.13 and 4.79 μM). Moreover, the compound 14 triggered remarkable apoptosis at a low concentration, and induced cell cycle arrest in G2/M phase in HCT116 cells. The biological assays conducted with normal cells (CHO) revealed that all the synthetic compounds are no selective against cancer cell lines tested.

Semisynthesis and Antifeedant Activity of New Derivatives of a Dihydro-β-Agarofuran from Parnassia wightiana

Five new derivatives (2–6) were semi-synthesized using compound 1, a dihydro-β-agarofuran sesquiterpene with C-2 ketone obtained from Parnassia wightiana, as the starting material by acylation, oxidation, reduction, esterification, and amination, respectively. Structures of 2–6 were confirmed by 1D- and 2D-NMR and HR-ESI-MS spectra. In addition, antifeedant activities of these compounds (1–6) were tested against the 3rd-instar larvae of Mythimna separata. Antifeedant effects of compounds 2 and 4 were greater than the parent compound 1 whereas other compounds exhibited low to no feeding deterrent effects against third instar M. separata larvae in lab bioassays. Therefore, our results suggest that acylated and reduced derivatives at C-8 and C-2, respectively, of 1 may improve the antifeeding effect. This preliminary information will be useful in designing new insect control agents against M. separata and other important pests.

Synthesis and cytotoxic activity of some novel steroidal C-17 pyrazolinyl derivatives.

Fourteen novel steroidal C-17 pyrazolinyl derivatives 9a-g and 10a-g were synthesized from commercially available progesterone and tested for their cytotoxic activity against brine shrimp (Artemia salina) and three human cancer cell lines (NCI-H460, HeLa, and HepG2). Some of these synthetic compounds exhibited significant cytotoxic activity, and treatment of HeLa cells with compound 10b resulted in the cell population arrest in the S phase. A structure-activity relationship was discussed.

Synthesis and cytotoxicity of some novel 21E-benzylidene steroidal derivatives.

A series of novel derivatives of 21E-benzylidene-pregn-1,4-diene-3,20-dione 7a-g and 21E-benzylidene-4-chloro-pregn-1,4-diene-3,20-dione 8a-g was synthesized from the commercially available progesterone. These title compounds were evaluated for their cytotoxic activity against brine shrimp (Artemia salina) and murine Lewis lung carcinoma cells (LLC). It was found that compounds 7a-g exhibited stronger activities than 8a-g against the brine shrimps, and some of the tested compounds possessed weak inhibition of LLC cells.

Synthesis of 1-O-acetylbritannilactone analogues from Inula britannica and in vitro evaluation of their anticancer potential

The natural product 1-O-acetylbritannilactone (ABL), a sesquiterpene lactone (STL) isolated from flowers of the medicinal plant Inula britannica, was found to have potent anticancer activity in vitro. Previous studies showed that the 6-OH side chain ester analogues of ABL displayed better anticancer activity. In order to look for new natural-product-based anticancer agents, a series of novel ABL analogues was synthesized by N/O-atom introduction and aromatic ring esterification at the 6-OH position of ABL, and the in vitro anticancer activities and mechanistic basis of cytotoxicity of the resulting compounds were investigated. Treatment of HeLa cells with the representative active compound 4a showed induction of apoptosis, as revealed by a biparametric cytofluorimetric analysis, and activation of caspase-3. The ability of 4a to obviously arrest the cell cycle at the G2/M phase was confirmed by flow cytometric analysis.

Potential Insecticidal Activity of Steroidal C-17 Pyrazolinyl Derivatives

Agrochemical research, over the last two decades, has resulted in the discovery of chemically novel insecticides, of which steroids-based compounds that mimic the action of hormones have been considered as safe insecticides. In this study, eight steroidal C-17 pyrazolinyl derivatives were resynthesized through molecular hybridization and their insecticidal activities against 4thinstar larvae of Mythimna separate were evaluated. These results showed that some compounds exhibited significant insecticidal activities and the susceptibility assays were expressed as the median lethal dose (LD50), of which one of the compounds exerted the most potent insecticidal activity (LD50 = 296 µg g-1), comparable to that of the natural product insecticide, celangulatin V (LD50 = 260 µg g-1). This strategy led to a promising candidate for the development of new steroidal insecticidal agents.

A new semisynthetic 1-O-acetyl-6-O-lauroylbritannilactone induces apoptosis of human laryngocarcinoma cells through p53-dependent pathway.

Initiation of apoptosis is an important event for chemoprevention and chemotherapy of cancer. Naturally derived products had drawn growing attention as lead compounds for anticancer drug discovery. ABL-L, a semisynthetic analogue of natural sesquiterpenoid 1-O-acetylbritannilactone (ABL) isolated from Inula britannica, showed stronger suppression against three solid tumor cell lines with 4-10 fold improvement than ABL. However, its molecular mechanism of cell death induction has still not been determined. The present study evaluated the anticancer efficacy of ABL-L and its biological activities mechanism on human laryngocarcinoma cells HEp-2 in vitro. We found that ABL-L-induced inhibition of cell proliferation was associated with an increase in G1-phase arrest. Typical apoptotic morphological and biochemical features were also observed in treated cells. Furthermore, the levels of the anti-apoptotic Bcl-2, pro-caspase 3/8/9 and poly(ADP-ribose) polymerase PARP decreased, and the level of pro-apoptotic Bax increased. Involvement of the caspase-mediated apoptosis was confirmed using caspase inhibitor Z-VAD-FMK pretreatment. In addition, ABL-L induced a tumor suppressor p53 and its target genes expression p21, fas, noxa and puma. The results of p53 knockdown suggest that caspase-mediated apoptosis induced by ABL-L was in p53-dependent pathway on HEp-2 cells. Our data indicate that the cytotoxicity of the novel semisynthetic analogue ABL-L involved G1 cell cycle arrest and apoptosis via a p53-dependent, caspase-mediated pathway on human laryngocarcinoma cells.

Synthesis and antiproliferative activity of D-ring substituted steroidal benzamidothiazoles

Using progesterone as the starting material, we synthesized a series of steroidal derivatives possessing a D-ring substituted benzamidothiazole. All of the final structures were reported and identified by NMR and HRMS spectrometry for the first time. The antiproliferative activity of the synthesized compounds against PC-3 (human prostate cancer cell line) and SKOV-3 (ovarian cancer cells) were investigated. The preliminary results showed that compounds 8b, 8d and 8g possessed moderate antiproliferative activities.

Synthesis of novel 4′-acylamino modified 21E-benzylidene steroidal derivatives and their cytotoxic activities

&NA; A series of 4′‐acylamino modified &Dgr;1,4‐pregnadien‐21E‐benzylidene‐3,20‐dione derivatives (6a–v) was synthesized from the commercially available progesterone (1). These title compounds were evaluated for their toxicity against brine shrimp (Artemia salina) and cytotoxic activities against two human cancer cell lines (HeLa and MCF‐7). The results revealed that compound 6f exhibited promising in vitro cytotoxic activity to the two cancer cell lines and the nature of acylamino functional group in the benzylidene moiety had a significant influence on cytotoxicity. Graphical abstract Figure. No caption available. HighlightsA series of 4′‐acylamino modified 21E‐benzylidene derivatives 6a–v were synthesized.Their toxicity against brine shrimp and in vitro cytotoxic activities were evaluated.Compound 6f produced promising cytotoxic activity against HeLa and MCF‐7 cells.

Constructing novel dihydrofuran and dihydroisoxazole analogues of isocombretastatin-4 as tubulin polymerization inhibitors through [3+2] reactions

[3+2] reactions play a key role in constructing various pharmaceutical moleculars. In this study, using Mn(OAc)3 mediated and 1,3-dipolar [3+2] cyclization reactions, 38 novel dihydrofuran and dihydroisoxazole analogues of isoCA-4 were synthesized as inhibitors of tubulin polymerization. Among them, compound 6g was found to be the most potent cytotoxic agents against PC-3 cells with IC50 value of 0.47μM, and compound 5p exhibted highest activity on HeLa cells with IC50 vaule of 2.32µM. Tubulin polymerization assay revealed that 6g was a dose-dependent and effective inhibitor of tubulin assembly. Immunohistochemistry studies and cell cycle distribution analysis indicated that 6g severely disrupted microtubule network and significantly arrested most cells in the G2/M phase of the cell cycle in PC-3 cells. In addition, molecular docking studies showed that two chiral isomers of 6g can bind efficiently and similarly at colchicine binding site of tubulin.