Design, Preparation and Studies Regarding Cytotoxic Properties of Glycyrrhetinic Acid Derivatives.

Glycyrrhetinic acid (GA) is a natural product with certain antitumor activity. In order to enhance the cytotoxicity, a total of eighteen derivatives of GA were designed and synthesized. Their cytotoxicity against MDA-MB-231cells (human breast cancer cells) and HeLa cells (human cervical cancer cells), were evaluated by the MTT method (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide). The results indicated that these target compounds have a wide molar activity range and some of them show better activity than the commercial drugs gefitinib and doxorubicin. Compound 6g induces apoptosis of 7, 10 and 44% of MDA-MB-231 cells at 5, 10, and 20 µM, respectively.

Design and preparation of derivatives of oleanolic and glycyrrhetinic acids with cytotoxic properties.

BACKGROUND: The structural modification of natural products with the aim to improve the anticancer activity is a popular current research direction. The pentacyclic triterpenoid compounds oleanolic acid (OA) and glycyrrhetinic acid (GA) are distributed widely in nature. METHODS: In this study, various oleanolic acids and glycyrrhetinic acids were designed and synthesized by using the combination principle. The in vitro anticancer activities of new OA and GA derivatives were tested by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method with SGC-7901 (gastric cancer), MCF-7 (breast cancer), Eca-109 (esophageal cancer), HeLa (cervical cancer), Hep-G2 (hepatoma cancer) and HSF (normal human skin fibroblast) cells. RESULTS AND CONCLUSION: The screening results showed that the compound 3m presented the highest inhibitory activities against SGC-7901, MCF-7 and Eca-109 cell lines with IC50 values of 7.57±0.64 µM, 5.51±0.41 µM and 5.03±0.56 µM, respectively. In addition, this compound also showed effective inhibition of Hep-G2 cells with an IC50 value of 4.11±0.73 µM. Moreover, compound 5b showed the strongest inhibitory activity against Hep-G2 cells with an IC50 value of 3.74±0.18 µM and compound 3l showed strong selective inhibition of the HeLa cells with the lowest IC50 value of 4.32±0.89 µM. A series of pharmacology experiments indicated that compound 5b could induce Hep-G2 cells autophagy and apoptosis. These compounds will expand the structural diversity of anti-cancer targets and confirm the prospects for further research.

Design and Synthesis of New Anticancer Glycyrrhetinic Acids and Oleanolic Acids.

A series of new glycyrrhetinic acids and oleanolic acids has been designed and synthesized based on the principles of combinatorial chemical synthesis. Their anticancer activities were further studied by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method with hepatocellular carcinoma (Hep-G2), breast cancer (MCF-7) cell lines and a normal hepatic cell (LO2). Cytotoxicity tests (in vitro) indicated that compound 6a showed the highest cytotoxicity with the lowest IC50 values of 23.34 µM on Hep-G2 cells, 12.23 µM on MCF-7 cells, and 44.47 µM on LO2, which would widen the structural diversity of these anticancer targets and confirm the perspectives of further investigations.

Synthesis and Anticancer Activities of Glycyrrhetinic Acid Derivatives.

A total of forty novel glycyrrhetinic acid (GA) derivatives were designed and synthesized. The cytotoxic activity of the novel compounds was tested against two human breast cancer cell lines (MCF-7, MDA-MB-231) in vitro by the MTT method. The evaluation results revealed that, in comparison with GA, compound 42 shows the most promising anticancer activity (IC50 1.88 ± 0.20 and 1.37 ± 0.18 µM for MCF-7 and MDA-MB-231, respectively) and merits further exploration as a new anticancer agent.

Synthesis and Biological Evaluation of Curcuminoid Derivatives.

Many curcuminoid derivatives have been reported to have multiple biological activities. The aim of this study was to improve the biological activity of curcuminoids by synthesizing 16 new derivatives which combined cinnamic acids with curcuminoids, and we also analyzed the structure-activity relationship of the new compounds. Almost all the new compounds showed encouraging activity, especially compound 7g. It had much better antioxidant activity than curcuminoids and Vitamin C (VC), and also had the most significant antibacterial activity, which was 5-folder better than ampicillin (one of the best marketed antibiotics) with a minimum inhibitory concentration (MIC) of 0.5 µg/mL against Gram-positive cocci (Staphylococcus aureus and Streptococcus viridans) as well as Escherichia coli and 0.6 µg/mL against Enterobacter cloacae. Compound 7g also showed the greatest anticancer activity with a much lower IC50, which was 0.51 µM against MCF-7, 0.58 µM against HepG-2, 0.63 µM against LX-2, and 0.79 µM against 3T3. The results suggest that these compounds have promising potential as candidates for the treatment of cancer and thus further studies are warranted.

Rearrangement of dypnones to 1,3,5-triarylbenzenes.

Rearrangement of dypnones to 1,3,5-triarylbenzenes is described. The reaction is proposed to involve an aldol-type self-condensation of dypnones, followed by an intramolecular [2 + 2] cycloaddition and a retro-[2 + 2] cycloaddition. The reaction goes smoothly under obviously milder conditions in comparison to the cyclotrimerization of acetophenones to 1,3,5-triarylbenzenes (10 mol % of TsOH, 80 °C versus 130-148 °C). This unexpected rearrangement would provide new possible considerations in dypnone-involved organic synthesis.

Synthesis and biological evaluation of novel curcuminoid derivatives.

Curcuminoids have been reported to possess multiple bioactivities, such as antioxidant, anticancer and anti-inflammatory properties. Three novel series of curcuminoid derivatives (11a-h, 15a-h and 19a-d) with enhanced bioactivity have been synthesized. Among the synthesized compounds, 11b exhibited the most significant activity with an MIC of 0.5 µM /mL against selected medically important Gram-positive cocci (S. aureus and S. viridans) and Gram-negative bacilli (E. coli and E. cloacae). The derivatives exhibited remarkable results in an antioxidant test with an IC50 2.4- to 9.3-folder smaller than curcuminoids. With respect to antiproliferative activity against Hep-G2, LX-2, SMMC7221 and MDA-MB-231, the derivatives exhibited an effect stronger than curcuminoids with an IC50 ranging from 0.18 to 4.25 µM.