Discovery of polymethoxyflavones as potential cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and phosphodiesterase 4B (PDE4B) inhibitors.

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed to treat inflammatory-related diseases, pain and fever. However, the prolong use of traditional NSAIDs leads to undesirable side effects such as gastric, ulceration, and renal toxicity due to lack of selectivity toward respective targets for COX-2, 5-LOX, and PDE4B. Thus, targeting multiple sites can reduce these adverse effects of the drugs and increase its potency. A series of methoxyflavones (F1-F5) were synthesized and investigated for their anti-inflammatory properties through molecular docking and inhibition assays. Among these flavones, only F2 exhibited selectivity toward COX-2 (Selectivity Index, SI: 3.90, COX-2 inhibition: 98.96 ± 1.47%) in comparison with celecoxib (SI: 7.54, COX-2 inhibition: 98.20 ± 2.55%). For PDEs, F3 possessed better selectivity to PDE4B (SI: 4.67) than rolipram (SI: 0.78). F5 had the best 5-LOX inhibitory activity among the flavones (33.65 ± 4.74%) but less than zileuton (90.81 ± 0.19%). Docking analysis indicated that the position of methoxy group and the substitution of halogen play role in determining the bioactivities of flavones. Interestingly, F1-F5 displayed favorable pharmacokinetic profiles and acceptable range of toxicity (IC50>70 µM) in cell lines with the exception for F1 (IC50: 16.02 ± 1.165 µM). This study generated valuable insight in designing new anti-inflammatory drug based on flavone scaffold. The newly synthesized flavones can be further developed as future therapeutic agents against inflammation.

Synthesis, Molecular Docking, and Antimalarial Activity of Hybrid 4-Aminoquinoline-pyrano[2,3-c]pyrazole Derivatives.

Widespread resistance of Plasmodium falciparum to current artemisinin-based combination therapies necessitate the discovery of new medicines. Pharmacophoric hybridization has become an alternative for drug resistance that lowers the risk of drug-drug adverse interactions. In this study, we synthesized a new series of hybrids by covalently linking the scaffolds of pyrano[2,3-c]pyrazole with 4-aminoquinoline via an ethyl linker. All synthesized hybrid molecules were evaluated through in vitro screenings against chloroquine-resistant (K1) and -sensitive (3D7) P. falciparum strains, respectively. Data from in vitro assessments showed that hybrid 4b displayed significant antiplasmodial activities against the 3D7 strain (EC50 = 0.0130 ± 0.0002 µM) and the K1 strain (EC50 = 0.02 ± 0.01 µM), with low cytotoxic effect against Vero mammalian cells. The high selectivity index value on the 3D7 strain (SI > 1000) and the K1 strain (SI > 800) and the low resistance index value from compound 4b suggested that the pharmacological effects of this compound were due to selective inhibition on the 3D7 and K1 strains. Molecular docking analysis also showed that 4b recorded the highest binding energy on P. falciparum lactate dehydrogenase. Thus, P. falciparum lactate dehydrogenase is considered a potential molecular target for the synthesized compound.

In vitro inhibitory and cytotoxic activity of MFM 501, a novel codonopsinine derivative, against Methicillin-Resistant Staphylococcus aureus clinical isolates.

28 new pyrrolidine types of compounds as analogues for natural polyhydroxy alkaloids of codonopsinine were evaluated for their anti-MRSA activity using MIC and MBC value determination assay against a panel of S. aureus isolates. One pyrrolidine compound, MFM 501, exhibited good inhibitory activity with MIC value of 15.6 to 31.3 µg/mL against 55 S. aureus isolates (43 MRSA and 12 MSSA isolates). The active compound also displayed MBC values between 250 and 500 µg/mL against 58 S. aureus isolates (45 MRSA and 13 MSSA isolates) implying that MFM 501 has a bacteriostatic rather than bactericidal effect against both MRSA and MSSA isolates. In addition, MFM 501 showed no apparent cytotoxicity activity towards three normal cell lines (WRL-68, Vero, and 3T3) with IC50 values of >625 µg/mL. Selectivity index (SI) of MFM 501 gave a value of >10 suggesting that MFM 501 is significant and suitable for further in vivo investigations. These results suggested that synthetically derived intermediate compounds based on natural products may play an important role in the discovery of new anti-infective agents against MRSA.

Antinociceptive activity of a synthetic oxopyrrolidine-based compound, ASH21374, and determination of its possible mechanisms.

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg ß-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

Ethyl 4-hy-droxy-1-methyl-5-oxo-2-phenyl-pyrrolidine-3-carboxyl-ate 1.25-hydrate.

The asymmetric unit of the title compound, C(14)H(17)NO(4)·1.25H(2)O, consists of four substituted pyrrolidone mol-ecules (two pairs of enanti-omers) and five water mol-ecules. The five-membered rings each have an envelope conformation, with the C atom bonded to the ester group as the flap. The mean planes of the five-membered rings of the four pyrrolidone mol-ecules make dihedral angles of 60.87 (5), 64.45 (5), 62.03 (5) and 65.79 (5)° with respect to the phenyl rings. In the crystal, the pyrrolidone and water mol-ecules are connected through O-H⋯O hydrogen bonds, forming a layer parallel to the ab plane. The two-dimensional network is further stabilized by inter-molecular C-H⋯O hydrogen bonds.

Evaluation of the bioactivity of novel spiroisoxazoline typecompounds against normal and cancer cell lines.

The aim of this study was to investigate the in vitro cellular activity of novel spiroisoxazoline type compounds against normal and cancer cell lines from lung tissue (Hs888Lu), neuron-phenotypic cells (SH-SY5Y), neuroblastoma (SH-SY5Y), human histiocytic lymphoma (U937), lung cancer (A549), and leukaemia (HL-60). Our bioassay program revealed that the spiroisoxazoline type compounds show cytotoxicity only in lymphoma cell lines, which is in contrast with the pyrrolidine precursor of these spiroisoxazoline compounds, where significant cytotoxicity is seen in all normal and cancer cell lines. These data suggest a tumour-specific mechanism of action. In addition these data also show that spiroisoxazoline compounds are non-toxic in the human neuronphenotypic neuroblastoma SH-SY5Y cell line, and furthermore that they might protect cells from neurodegenerative disease.

6-Benzyl-3-(1,4-dioxaspiro-[4.5]decan-2-yl)-8,8-dimethyl-1-oxa-2,6-diaza-spiro-[4.4]non-2-ene-7,9-dione.

In the title compound, C(23)H(28)N(2)O(5), the 4,5-dihydro-isoxazole ring adopts a slight envelope conformation and the dioxolane ring is in a twisted conformation. The mol-ecular structure, in the vicinity of the benzyl group, may be influenced by an intra-molecular C-H⋯O hydrogen bond which generates an S(7) ring motif. In the crystal structure, mol-ecules are linked via weak inter-molecular C-H⋯O hydrogen bonds, forming extended chains along the b axis. Further stabilization is provided by weak C-H⋯π inter-actions.

4-Hydr-oxy-5-(4-methoxy-phen-yl)pyrrolidin-2-one.

In the title compound, C(11)H(13)NO(3), the pyrrolidin-2-one ring is in an envelope conformation with the hydroxyl and 4-methoxy-phenyl substituents mutually cis. The methoxy group is slighty twisted away from the mean plane of the attached benzene ring. The mol-ecules are arranged into screw chains along the c axis. These chains are inter-connected via inter-molecular O-H⋯O and N-H⋯O hydrogen bonds into sheets parallel to the ac plane. The crystal structure is further stabilized by weak inter-molecular C-H⋯O and C-H⋯π inter-actions.

tert-Butyl 5-(4-methoxy-phen-yl)-1-methyl-2-oxopyrrolidin-3-yl carbonate.

In the title compound, C(17)H(23)NO(5), the pyrrolidinone ring is in an envelope conformation. The tert-butyl carbonate and 4-methoxy-phenyl groups are arranged on the same side of the pyrrolidinone ring. The meth-oxy group is coplanar with the attached benzene ring. The mol-ecules are linked into chains along the b axis via C-H⋯O hydrogen bonds.

Methyl 2-{[(4-hydroxy-phen-yl)(methoxy-carbon-yl)meth-yl]amino-carbon-yl}ethano-ate hemihydrate.

In the structure of the title compound, C(13)H(15)NO(6)·0.5H(2)O, the water O atom lies on a twofold rotation axis. The methoxy-carbonyl-methyl and amino groups are essentially coplanar and the methoxy-carbonyl-methyl group makes a dihedral angle of 79.73 (10)° with the mean plane of the hydroxy-phenyl ring. The amino and methoxy-carbonyl-methyl groups are involved in an intra-molecular N-H⋯O hydrogen bond which generates an S(5) ring motif. In the crystal structure, mol-ecules are linked via N-H⋯O and O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions into a two-dimensional network parallel to the (01) plane. The crystal structure is further stabilized by C-H⋯π inter-actions.