Ping-Hua Sun

Betulinic Acid and its Derivatives as Potential Antitumor Agents

Betulinic acid (BA) is a lupane‐type pentacyclic triterpene, distributed ubiquitously throughout the plant kingdom. BA and its derivatives demonstrate multiple bioactivities, particularly an antitumor effect. This review critically describes the recent research on isolation, synthesis, and derivatization of BA and its natural analogs betulin and 23‐hydroxybetulinic acid. The subsequent part of the review focuses on the current knowledge of antitumor properties, combination treatments, and pharmacological mechanisms of these compounds. A 3D‐QSAR analysis of 62 BA derivatives against human ovarian cancer A2780 is also included to provide information concerning the structure–cytotoxicity relationships of these compounds.

3D-QSAR and docking studies on pyrazolo[4,3-h]qinazoline-3-carboxamides as cyclin-dependent kinase 2 (CDK2) inhibitors

3D-QSAR and docking studies were performed on a series of pyrazolo[4,3-h]quinazoline-3-carboxamides as CDK2/CyA inhibitors. The CoMFA and CoMSIA models using 54 molecules in the training set, gave r(cv)(2) values of 0.644 and 0.507, r(2) values of 0.959 and 0.951, respectively. 3D contour maps generated from the two models were applied to identify features important for the activity and better understand the interaction between the inhibitors and the receptor. Molecular docking was employed to explore the binding mode between these compounds and the receptor, as well as help understanding the structure-activity relationship revealed by CoMFA and CoMSIA. The results provide a useful guideline for the rational design of novel CDKs inhibitors.

Synthesis and antiproliferative evaluation of 23-hydroxybetulinic acid derivatives.

Based on structural modifications of the natural 23-hydroxybetulinic acid, a series of novel its derivatives had been synthesized. The new compounds were screened for in vitro antiproliferative activity against cancer cell lines HeLa, MCF-7, HepG2, B16 and A375 using doxorubicin as a reference. The vast majority of derivatives had exhibited potent tumor growth inhibitory activity than original compound. The derivatives 4, 5, 7, 20, 23, 26, 43 and 44 with IC50 values lower than 10 μM on all tested cell lines were regarded as the most promising compounds. The structure-activity relationships of 23-hydroxybetulinic acid derivatives were also discussed in the present investigations.

Exploring QSARs for 5-Lipoxygenase (5-LO) Inhibitory Activity of 2-Substituted 5-Hydroxyindole-3-Carboxylates by CoMFA and CoMSIA

A series of indole and related benzo[g]indole compounds displaying potent activities against 5‐lipoxygenase were selected to establish three‐dimensional quantitative structure–activity relationships using comparative molecular field analysis and comparative molecular similarity indices analysis methods. A training set of 37 active compounds was used to develop the models, which were then valuated by a series of internal and external cross‐validation techniques. A test set of seven compounds was used for the external validation. Models with greater than 70% predictive ability, as determined by external validation, and high internal validity (cross‐validated q2 > 0.5) have been developed. The satisfactory comparative molecular field analysis model predicted a q2 value of 0.779 and an r2 value of 0.957 and revealed that electrostatic and steric properties play a significant role in potency. The best comparative molecular similarity indices analysis model, based on a combination of steric, hydrophobic, and H‐bond donor effects, predicted a q2 value of 0.816 and an r2 value of 0.953. The models were graphically interpreted using comparative molecular field analysis and comparative molecular similarity indices analysis contour plots that provided insight into the structural requirements for increasing the activity of a compound. The results obtained from this study provide a solid basis for future rational design of more active 5‐lipoxygenase inhibitors.

A facile and efficient one-step strategy for the preparation of β-cyclodextrin monoliths

A novel, facile, and efficient one-step copolymerization strategy was developed for the preparation of β-cyclodextrin (β-CD) methacrylate monolithic columns using click chemistry. The novel mono-(1H-1,2,3-triazol-4-ylmethyl)-2-methylacryl-β-CD monomer was synthesized by a click reaction between propargyl methacrylate and mono-6-azido-β-CD, and then monolithic columns were prepared through a one-step in situ copolymerization of the mono-(1H-1,2,3-triazol-4-ylmethyl)-2-methylacryl-β-CD monomer and ethylene dimethacrylate. The physicochemical properties and column performance of the fabricated monolithic columns were characterized by elemental analysis, SEM, and micro-HPLC. Satisfactory column permeability, efficiency, and separation performance were obtained for the optimized poly(mono-(1H-1,2,3-triazol-4-ylmethyl)-2-methylacryl-β-CD-co-ethylene dimethacrylate) monolithic columns. Additionally, typical hydrophilic interaction chromatography retention behavior was observed on the monoliths at high acetonitrile content in the mobile phase. Although the enantioselectivity of our monolithic columns did not meet the level of other reported β-CD monolithic columns, this one-step strategy based on click chemistry still provides an interesting and effective model as it offers the possibility to easily prepare related novel CD methacrylate monoliths through a one-step copolymerization strategy.

New eudesmane sesquiterpenes from Alpinia oxyphylla and determination of their inhibitory effects on microglia

The fruits of Alpinia oxyphylla are used as healthcare products for the protection on neurons and prevention of dementia. Two new noreudesmane sesquiterpenoids, (5R,7S,10S)-5-hydroxy-13-noreudesma-3-en-2,11-dione (1) and (10R)-13-noreudesma-4,6-dien-3,11-dione (2), and a new eudesmane sesquiterpenoid, (5S,8R,10R)-2-oxoeudesma-3,7(11)-dien-12,8-olide (3), as well as 12 known sesquiterpenoids, were isolated from the fruits of A. oxyphylla. The structures of the new compounds (1-3) were elucidated on the basis of spectroscopic data and circular dichroism experiments. All isolates were evaluated their neuroprotective potential by inhibitory assay on nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-induced mouse microglia BV-2 cells.

Synthesis, molecular docking, and biofilm formation inhibitory activity of 5-substituted 3,4-dihalo-5h-furan-2-one derivatives on Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) colonize on most wounds and live as biofilm, which causes antibiotic resistance and wounds unhealed. To investigate the effects of 5‐substituted 3,4‐dihalo‐5H‐furan‐2‐one compounds on biofilm formation of P. aeruginosa, a set of 5‐(aryl‐1′‐hydroxy‐methyl)‐ or 5‐(aryl‐2‐methylene)‐3,4‐dihalo‐5H‐furan‐2‐one compounds were designed and synthesized. Their inhibitory activities on biofilm formation of P. aeruginosa were studied by MIC assay, quantitative analysis of biofilm inhibition, and observation of biofilm formation with SEM. It was found that compounds 2i, 3f, 3i showed remarkable effects of biofilm formation inhibition on P. aeruginosa. Furthermore, molecular docking was performed to identify the key structural features of these compounds with the binding site of LasR receptor.

Understanding the structure-activity relationship of betulinic acid derivatives as anti-HIV-1 agents by using 3D-QSAR and docking

AbstractNovel anti-HIV-1 agents derived from betulinic acid have been greatly concerned. 3D-QSAR and molecular docking studies were applied to rationalize the structural requirements responsible for the anti-HIV activity of these compounds. The CoMFA and CoMSIA models resulted from 28 molecules gave rcv2 values of 0.599 and 0.630, r2 values of 0.994 and 0.958, respectively. To estimate the predictive ability of the 3D-QSAR model, an external validation was employed. Based on the contour maps generated from both CoMFA and CoMSIA, we have identified some key features in the betulinic acid derivatives that are responsible for the anti-HIV activity. Molecular docking was used to explore the binding mode between these derivatives and HIV gp120. We have therefore designed a series of novel betulinic acid derivatives by utilizing the SAR results revealed in the present study, which were predicted with excellent potencies in the developed models. The results provide a valuable method to design new betulinic acid derivatives as anti-HIV-1 agents. Figure3D-QSAR and molecular docking studies were applied to rationalize the structural requirements responsible for the anti-HIV activity of betulinic acid derivatives.

Anti-Inflammatory Effects of Cajaninstilbene Acid and Its Derivatives

Cajaninstilbene acid (CSA) is one of the active components isolated from pigeon pea leaves. In this study, anti-inflammatory effects of CSA and its synthesized derivatives were fully valued with regard to their activities on the production of nitric oxide (NO) and pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in vitro cell model, as well as their impacts on the migration of neutrophils and macrophages in fluorescent protein labeled zebrafish larvae model by live image analysis. Furthermore, the anti-inflammatory mechanism of this type of compounds was clarified by western-blot and reverse transcription-polymerase chain reaction (RT-PCR). The results showed that CSA, as well as its synthesized derivatives 5c, 5e and 5h, exhibited strong inhibition activity on the release of NO and inflammatory factor TNF-α and IL-6 in lipopolysaccharides (LPS)-stimulated murine macrophages. CSA and 5c greatly inhibited the migration of neutrophils and macrophages in injury zebrafish larvae. CSA and 5c treatment greatly inhibited the phosphorylation of proteins involved in nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Moreover, we found that peroxisome proliferator-activated receptor gamma (PPARγ) inhibitor GW9662 could reverse partly the roles of CSA and 5c, and CSA and 5c treatment greatly resist the decrease of PPARγ mRNA and protein induced by LPS stimulation. Our results identified the promising anti-inflammatory effects of CSA and its derivatives, which may serve as valuable anti-inflammatory lead compound. Additionally, the mechanism studies demonstrated that the anti-inflammatory activity of CSA and its derivative is associated with the inhibition of NF-κB and MAPK pathways, relying partly on resisting the LPS-induced decrease of PPARγ through improving its expression.

3D-QSAR and molecular docking studies of azaindole derivatives as Aurora B kinase inhibitors

AbstractThe Aurora kinases have been regarded as attractive targets for the development of new anticancer agents. Recently a series of azaindole derivatives with Aurora B inhibitory activities were reported. To explore the relationship between the structures of substituted azaindole derivatives and their inhibition of Aurora B, 3D-QSAR and molecular docking studies were performed on a dataset of 41 compounds. 3D-QSAR, including CoMFA and CoMSIA, were applied to identify the key structures impacting their inhibitory potencies. The CoMSIA model showed better results than CoMFA, with r2cv value of 0.575 and r2 value of 0.987. 3D contour maps generated from CoMFA and CoMSIA along with the docking binding structures provided enough information about the structural requirements for better activity. Based on the structure-activity relationship revealed by the present study, we have designed a set of novel Aurora B inhibitors that showed excellent potencies in the developed models. Thus, our results allowed us to design new derivatives with desired activities. FigureUpper panel Alignment of the compounds used in the training set, lower panel binding mode between compound 36 and the ATP pocket of Aurora B (PDB code 2VGO). Key residues and hydrogen bonds are labeled