Guangyi Liang

Simultaneous Determination of Seven Bioactive Compounds in Wuji Pill by HPLC

A high performance liquid chromatography coupled with photodiode-array detection method was developed for simultaneous determination of gallic acid, chlorogenic acid, paeoniflorin, jatrorrhizine hydrochloride, dehydroevodiamine, palmatine chloride and berberine hydrochloride in the Chinese proprietary medicine “Wuji Pill” (WJP). The analysis was performed by reversed phase gradient elution, using an aqueous mobile phase (containing 0.05 mol/L monopotassium phosphate and 0.1% aqueous phosphosnic acid) modified by acetonitrile and detection made at 340 nm. The method was validated for limits of detection and quantification, precision, repeatability, stability, accuracy and robustness. Five batches of self-manufactured WJP were analyzed and found to contain different amounts of the seven bioactive markers. The method could be used for quality assessment of this Chinese materia medica preparation.

Novel 3′,5′-diprenylated chalcones inhibited the proliferation of cancer cells in vitro by inducing cell apoptosis and arresting cell cycle phase

A double Claisen rearrangements synthetic strategy was established for the total synthesis of 4,4-dimethyl medicagenin (compound 6c). A series of its analogs also were prepared, including two novel 3,5-diprenylated chalcones, in which ring B was replaced by azaheterocycle. The structures of the twenty-two newly synthesized compounds were confirmed by 1H NMR, 13C NMR and ESI-MS. Inxa0vitro, the cytotoxicity of the target compounds was evaluated using cancer cells. Noticeably, compound 10 exhibited broad-spectrum cytotoxicity on PC3 prostate cancer cells, MDA-MB-231 breast cancer cells (MDA), HEL and K562 erythroleukemia cells with IC50 values of 2.92, 3.14, 1.85 and 2.64xa0μM, respectively. Further studies indicated that compound 10 induced apoptosis and arrested the cell cycle phase of the above mentioned four cancer cell lines. By contrast, compound 6g selectively displayed potent inhibitory activity against the proliferation of HEL cells with an IC50 value of 4.35xa0μM. Compound 6g slightly induced apoptosis and arrested cell cycle phase of HEL cells. Preliminary structure-activity relationship studies indicated that, in all cancer cell lines evaluated, the 3-pyridinyl group was essential for cytotoxicity.

In silico Molecular Docking Study of Repensine and Bentysrepinine against HBV DNA Polymerase

Abstract Bentysrepinine (Y101), a derivative of repensine, is a novel di-peptide structure isolated from Dichondra repens. In vitro and in vivo tests exhibited that bentysrepinine markedly inhibited DNA-HBV and cccDNA activities. The binding mode of Y101 and repensine with DNA polymerase was driven by hydrophobic interactions. This might provide novel recognition of inhibitory effect of Y101 against HBV, though its inhibition mechanism needs to be validated by bio-assay at cellular level and of polymerase activity. Preliminary docking study suggested that Y101 might be able to inhibit HIV inverse transcriptase, also have the potential to interact with DNA polymerase and HCV NS5B polymerase.

Metabolite identification of bentysrepinine (Y101), a novel anti-HBV agent in rats using a five-step strategy based on a combined workflow with two different platforms of liquid chromatography–tandem mass spectrometry

Bentysrepinine (Y101), a derivative of repensine (a compound isolated from Dichondrarepens Forst), is a novel phenyalanine dipeptide inhibiting DNA-HBV and cccDNA activities and is currently under development for the treatment of hepatitis B virus (HBV)-infected hepatitis. Our previous study implied that there might be an existence of extensive metabolism of Y101 in rats. Therefore, it is necessary to perform metabolic profiling study to further evaluate its safety and drug-like properties. In this study, the metabolism of Y101 in rats was investigated by a convincible five-step strategy to characterize metabolites in plasma and that excreted into urine, bile and feces. The five-step strategy was realized by using an combined workflow on two different MS platforms, including various scan modes of liquid chromatography with hybrid quadruple-linear ion trap mass spectrometry (LC-QTRAP-MS/MS) and various post-acquiring data mining tools of liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS/MS). QTOF MS/MS was employed as a powerful complementary tool to enable high confidence of metabolites identification using its functions of accurate MS and MS/MS fragmentation. As a result, a total of 30 metabolites were detected, including 25 phase I and 5 phase II metabolites. Among them, four primary metabolites (M6-M9) were further identified by comparing with the authentic standards chemically synthesized. The possible metabolic pathways of Y101 in rats were proposed to be amide hydrolysis, monohydroxylation, dihydroxylation, N-oxidation, demethylation, methylation, glucosidation and glucuronidation. This is the first study of the metabolism of Y101 in rats. The five-step strategy was successfully used to systematically characterize metabolites of Y101 in rats, and it would be generally applied for metabolite identification of new drug candidate.

Syntheses and Anti-cancer Activities of Glycosylated Derivatives of Diosgenin

In order to obtain better anti-cancer compounds, nine glycosylated derivatives were designed and synthe-sized using diosgenin as starting material. Their structures were confirmed by 1H NMR, 13C NMR and MS spectra. The anti-cancer activities of intermediate compounds 5a—5i and the target compounds 6a—6i were investigated against human leukemia HEL, K562, HL60 and melanoma WM9 cell lines via MTT method. The bioassay results show that these derivatives possess good inhibitory activities against the four cancer cell lines. Furthermore, these derivatives show better inhibitory activities against K562 than against other cell lines, and most derivatives show better inhibitory activities than the parental material. Moreover, compounds 6a—6i are more active than their inter-mediates 5a—5i when against these cells. The above results demonstrate the effects of glycosylation on 3-OH of di-osgenin and acetylation of the sugar moiety on their antitumor activities.

Process development of clinical anti-HBV drug Y101: identification and synthesis of novel impurities

AbstractnNine novel process impurities of N-[N-benzoyl-O-(2-dimethylaminoethyl)-l-tyrosyl]-l-phenylalaninol (Y101) observed during the laboratory optimization and later during its bulk synthesis are described in this article. The impurities were monitored by HPLC, and their structures were tentatively assigned on the basis of fragmentation patterns in LC−MS/MS and NMR spectroscopies. All of the impurities were synthesized, and their assigned constitutions were confirmed by co-injection in HPLC. In addition to the formation, synthesis, and characterization, the strategy for minimizing these impurities to a level accepted by the International Conference on Harmonisation (ICH) was also described.n

Synthesis and Biological Evaluation of Matijin-Su Derivatives as Potential Antihepatitis B Virus and Anticancer Agents

A series of Matijin‐Su (MTS, (2S)‐2‐{[(2S)‐2‐benzamido‐3‐phenylpropanoyl]amino}‐3‐phenylpropyl acetate) derivatives were synthesized and evaluated for their anti‐HBV and cytotoxic activities in vitro. Six compounds (4g, 4j, 5c, 5g, 5h and 5i) showed significant inhibition against HBV DNA replication with the IC50 values in range of 2.18 – 8.55 μm, which were much lower than that of positive control lamivudine (IC50 82.42 μm). In particular, compounds 5h (IC50 2.18 μm; SI 151.59) and 5j (IC50 5.65 μm; SI 51.16) displayed relatively low cytotoxicities, resulting in high SI values. Notably, besides the anti‐HBV DNA replication activity, compound 4j also exhibited more potent in vitro cytotoxic activity than 5‐fluorouracil in two hepatocellular carcinoma cell (HCC) lines (QGY‐7701 and SMMC‐7721), indicating that 4j may be a promising lead for the exploration of drugs with dual therapeutic effects on HBV infection and HBV‐induced HCC.

Novel sesquiterpenoids isolated from Chimonanthus praecox and their antibacterial activities

In the present study, four new sesquiterpenoids, chimonols A-D (compounds 1-4), together with four known compounds (5-8) were isolated from the EtOAc extract of Chimonanthus praecox Link. The structures of these new compounds were elucidated on the basis of spectroscopic techniques (UV, IR, MS, and 1D and 2D NMR), and their absolute configurations were established by comparing experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1-8 were evaluated for antimicrobial activities and the minimum inhibitory concentrations (MICs) were determined by the broth microdilution method in 96-well culture plates. Compounds 1, 2, and 7 exhibited weak antibacterial effects for S. aureus (ATCC 6538), E. coli (ATCC 11775), and P. aeruginosa (ATCC 10145) with MIC values being 158-249 µg·mL-1. Compounds 3-7 showed activities against C. glabrata (ATCC 2001) and S. aureus (ATCC 43300) with MIC values being 128-197 µg·mL-1. Compounds 1-4 showed activity against S. aureus (ATCC 25923) with MIC values being 162-254 µg·mL-1. The present study provided a basis for future evaluation of these compounds as antibacterial agents.

A novel synthesized 3’, 5’-diprenylated chalcone mediates the proliferation of human leukemia cells by regulating apoptosis and autophagy pathways

Leukemia is a hematologic malignancy with poor prognosis in humans and chemotherapy is the main strategy for treating leukemia patients. Novel drugs with better selectivity and lower toxicity are required for the treatment of patients. A novel 3,5-diprenylated chalcone, (E)-1-(2-hydroxy-4-methoxy-3,5-diprenyl) phenyl-3-(3- pyridinyl)-propene-1-one (C10) is a potential new anti-leukemia agent. In this study, we investigated the molecular mechanisms of the anti-leukemia effects of C10 on different leukemia cells in vitro. C10 showed strong inhibition of proliferation of the human erythroleukemia cell line HEL and human myeloid leukemia cell line K562, and several cell and flow cytometer assays showed that inhibition by C10 was due to the regulation of gene expression or phosphorylation in the apoptosis and autophagy pathways. The results showed that C10 regulated the expression of Bax, c-Myc, Bcl-2, P38/AMPK and ERK 1/2, activated the expression of Caspase-3, -8, and PARP at the protein level in the apoptosis pathway of the two leukemia cell types, and inhibited the expression of erythroleukemia carcinogene Fli-1 in the human erythroleukemia cell line HEL. Additionally,treatment with the compound induced a time-dependent increase in expression of LC 3A/B via inhibiting the AKT-mTOR pathway, which is associated with cell autophagy. Taken together, the above results suggest that the novel synthesized 3,5-diprenylated chalcone can prevent the growth of leukemia cells by inducing apoptosis and autophagy.

Synthesis of Quercetin Glycosides and Their α-Glucosidase Inhibitory Activities

A series of quercetin glycosides as the analogues of 3,5,5-trimethyl-7-O-β-D-glucopyranosylquercetin (8) were synthesized, their structures were confirmed by 1H NMR, 13C NMR and MS. The inhibitory activities of those compounds against α-glucosidase were evaluated in vitro, in particular, the compounds V-c and V-d-2 showed promising bioactivities with IC50 of 19.4 μmol·L–1 and 19.7 μmol·L–1, are much higher than 8 (IC50 > 100 μmol·L–1). This research will provide a reference in the study of the synthetic methods and hypoglycemic activity for the quercetin glycosides. Diabetes mellitus is metabolic disorder characterized by insufficient secretion or inefficient processing of hormonal insulin and it is becoming the third leading cause of death, after cancer and cardiovascular diseases.1 The number of people with diabetes has increased from 153 million in 1980 to 382 million in 2013. The International Diabetes Federation (IDF) predicted that the number of people with diabetes will increase to 435 million in 2030.2 One of therapeutics for diabetes is inhibition of α-glucosidase which is the key enzyme of carbohydrate digestion by specifically hydrolyzing the α-glucopyranoside bond to release α-D-glucose from the non-reducing end of the sugar. Therefore, the inhibition of α-glucosidase is an effective approach in preventing and treating diabetes through reduction of postprandial hyperglycaemia.3,4 At present, though some inhibitors have potent effect on α-glucosidase, the corresponding side effects cannot be ignored. For example, acarbose probably causes abdominal distension, flatulence and meteorism.5 In recent years, large amount of synthetic chemicals or natural products have been screened to get more effective and safe α-glucosidase inhibitors.6 Searching lead compounds from natural products HETEROCYCLES, Vol. 92, No. 7, 2016 1245