Synthesis and hypolipidaemic evaluation of a series of alpha-asarone analogues related to clofibrate in mice

Synthesis, crystal structure and bioactivities of α-asaronol

α-Asaronol [or (E)-3′-hydroxyasarone; systematic name: (E)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-ol; C12H16O4] was synthesized towards the development of a potential antiepileptic drug. Following purification by recrystallization, single crystals of α-asaronol were obtained by a liquid interface diffusion method at room temperature. The product was characterized by 1H and 13C NMR, and FT–IR spectroscopic analysis. X-ray crystallography revealed the title crystal to belong to the orthorhombic space group P212121. Preliminary bioassays with mouse neuroblastoma N2a cells demonstrated the neuroprotective activities of the synthesized α-asaronol.

Mixed natural arylolefin-quinoline platinum(II) complexes: synthesis, structural characterization and in vitro cytotoxicity studies

Five new platinum(II) complexes bearing a eugenol and a quinoline derivative, namely [η²-4-allyl-2-methoxy-1-(propoxycarbonylmethoxy)benzene]-trans-dichlorido(quinoline-κN)platinum(II), [PtCl₂(C₁₅H₂₀O₄)(C₉H₇N)], (2), {η²-4-allyl-2-methoxy-1-[(propan-2-yloxy)carbonylmethoxy]benzene}-trans-dichlorido(quinoline-κN)platinum(II), [PtCl₂(C₁₅H₁₉O₄)(C₉H₇N)], (3), [η²-4-allyl-2-methoxy-1-(propoxycarbonylmethoxy)benzene]chlorido(quinolin-8-olato-κ²N,O)platinum(II), [Pt(C₉H₆NO)Cl(C₁₅H₂₀O₄)], (4), {η²-4-allyl-2-methoxy-1-[(propan-2-yloxy)carbonylmethoxy]benzene}chlorido(quinolin-8-olato-κ²N,O)platinum(II), [Pt(C₉H₆NO)Cl(C₁₅H₂₀O₄)], (5), and [η²-4-allyl-2-methoxy-1-(propoxycarbonylmethoxy)benzene]chlorido(quinolin-2-carboxylato-κ²N,O)platinum(II), [Pt(C₁₀H₆NO₂)Cl(C₁₅H₂₀O₄)], (6), have been synthesized and fully characterized spectroscopically. A single-crystal X-ray diffraction study was carried out for complexes (2) and (4)-(6). PrEug [or 4-allyl-2-methoxy-1-(propoxycarbonylmethoxy)benzene] in (2), (4) and (6), and ⁱPrEug (the propan-2-yloxy analogue of PrEug) in (3) and (5) coordinate with Pt^II at the ethylenic double bond of the allyl group. In (2)-(6), the donor N atom of the amine group occupies a trans position with respect to the double bond. A comparison of the IC₅₀ values of 0.38-29.23 µM for (2)-(6) with cisplatin, as well as other platinum(II) complexes, indicates an excellent in vitro cytotoxicity against the KB, LU, Hep-G2 and MCF-7 cancer cell lines, with the highest cytotoxic effect (IC₅₀ = 0.38-1.99 µM) being for complexes (4) and (5) bearing a quinolin-8-olate ligand.

Developing Neolignans as Proangiogenic Agents: Stereoselective Total Syntheses and Preliminary Biological Evaluations of the Four Guaiacylglycerol 8-O-4'-Coniferyl Ethers

Stereoselective total syntheses of the four stereoisomeric forms of guaiacylglycerol 8-O-4'-coniferyl ether, viz., compounds 1, ent-1, 2, and ent-2, have been established. The key step involves an Evans/Seebach auxiliary-controlled and syn-selective aldol process followed, in the reaction sequences leading to the anti-compounds, by a Mitsunobu reaction involving a benzylic alcohol residue. The proangiogenic properties of the synthetic materials were evaluated in a human microvascular endothelial cell tubule formation assay, thus revealing that they are all active, with the 8S-configured compounds 1 and 2 being the most potent.

Separation of cis- and trans-Asarone from Acorus tatarinowii by Preparative Gas Chromatography

A preparative gas chromatography (pGC) method was developed for the separation of isomers (cis- and trans-asarone) from essential oil of Acorus tatarinowii. The oil was primarily fractionated by silica gel chromatography using different ratios of petroleum ether and ethyl acetate as gradient elution solvents. And then the fraction that contains mixture of the isomers was further separated by pGC. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d.), and then the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID) for detection and the remaining 99% was directed to the fraction collector. Two isomers were collected after 90 single injections (5 uL) with the yield of 178 mg and 82 mg, respectively. Furthermore, the structures of the obtained compounds were identified as cis- and trans-asarone by (1)H- and (13)C-NMR spectra, respectively.

Synthesis and biological evaluation of orally active hypolipidemic agents

A series of novel fenofibric acid ester prodrugs 1c-1h were synthesized and evaluated with the aim of obtaining potent hypolipidemic agents. Prodrugs 1c and 1d exhibited potent hypochlolesterolemic activity, lowering the mice plasma triglyceride level up to 47% in Swiss albino mice after oral administration of 50 mg/kg/day for 8 days. Fenofibric acid ester prodrugs 1c-1h were found lipophilic like fenofibrate (1b), indicated by partition coefficients measured in octanol-buffer system at pH 7.4. On the basis of in vivo studies, prodrugs 1c and 1d emerged as potent hypolipidemic agents.

Hypolipidaemic and antiplatelet activity of phenoxyacetic acid derivatives related to α-asarone

The phenoxyacetic acid derivatives 1–6 [2-methoxy-4-(2-propenyl)phenoxyacetic acid (1); 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetic acid (2); methyl 2-methoxy-4-(2-propenyl)phenoxyacetate (3); ethyl 2-methoxy-4-(2-propenyl)phenoxyacetate (4); methyl 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetate (5); ethyl 2-methoxy-5-nitro-4-(2-propenyl)phenoxyacetate (6)] related to α-asarone have been reported previously as hypolipidaemic agents in diet-induced hyperlipidaemic mice. We have aimed to expand the pharmacological profile of these derivatives by investigating their hypolipidaemic activity in rats and mice under different experimental conditions. The antiplatelet activity was tested also in-vitro from blood derived from consenting healthy volunteers. In normolipidaemic rats, compounds 2, 3 and 5 at oral doses of 40 and 80 mg kg−1 significantly decreased total cholesterol and LDL-cholesterol levels. Moreover, analogues 3 and 5 administered to hypercholesterolaemic rats at the same doses for seven days also produced a reduction in the content of these same lipoproteins. In neither case were the high-density lipoprotein cholesterol and triglyceride concentrations affected. However, practically all tested compounds were found to be hypocholesterolaemic agents, and were shown to effectively lower low-density lipoprotein cholesterol and triglyceride levels in Triton-induced hyperlipidaemic mice at oral doses of 50 and 100 mg kg−1. In all tests, all animals appeared to be healthy throughout the experimental period in their therapeutic ranges. Triton-induced hypercholesterolaemic mice appeared to be a desirable model for this class of hypolipidaemic drugs. On the other hand, compounds 1, 2, 4 and 5 significantly inhibited ADP-induced aggregation in-vitro. These findings indicated that all of these compounds appeared to be promising for the treatment of human hyperlipidaemia and thrombotic diseases.

Effect of ?-asarone and a derivative on lipids, bile flow and Na+/K+-ATPase in ethinyl estradiol-induced cholestasis in the rat

Administration of ethinyl estradiol (EE), a widely used component of oral contraceptives, has been associated with impairment of bile flow and the capacity to excrete organic anions in man and experimental animals. alpha-Asarone (2,4,5-trimethoxypropenylbenzene) and 2-methoxy-4-(2-propenyl) phenoxyacetic acid (MPPA) have shown hypolipidemic effects. In addition to these effects, we decided to evaluate the properties of these compounds on EE-induced cholestasis. Wistar male rats were injected subcutaneously with 10 mg/kg of EE for 5 days; simultaneously, alpha-asarone or MPPA were also administered and appropriate controls were performed. alpha-asarone and MPPA decreased plasma and bile cholesterol. EE diminished triglycerides total, low-density lipoprotein, high-density lipoprotein and bile cholesterol. MPPA further decreased these lipid parameters. Alkaline phosphatase (an enzyme marker of cholestasis) was increased after administration of EE, but this effect was prevented significantly by alpha-asarone or MPPA administration. Bile flow was importantly decreased by EE and increased by alpha-asarone alone. Furthermore, alpha-asarone or MPPA preserved the normal bile flow in EE-treated rats. EE inhibited the activity of the Na(+)/K(+)-ATPase, while both alpha-asarone and MPPA preserved this enzyme activity. Na(+)/K(+)-ATPase is involved in Na(+)-coupled uptake of bile acids into hepatocytes and, therefore, ultimately is the driving force for the generation of bile flow. Therefore, the anticholestatic effects of alpha-asarone and MPPA, described herein by the first time, may be due to its ability to preserve ATPase activity. This enzyme is negatively regulated by membrane cholesterol, thus the hypolipidemic effects of the compounds tested may be responsible for Na(+)/K(+)-ATPase activity and bile flow maintenance.

3D QSAR study of hypolipidemic asarones by comparative molecular surface analysis

Three-dimensional quantitative structure-activity relationship (3D QSAR) modeled for alpha-asarone derivatives using the comparative molecular surface analysis (CoMSA) allowed us to reveal a correlation between the activity of these compounds and the electrostatic potential at the molecular surface. The grid formalism (s-CoMSA) allowed us to indicate a pharmacophore that is of key importance for compound activity. The CoMSA formalism coupled with the iterative variable elimination method gives a highly predictive model.

Modeling robust QSAR. 1. Coding molecules in 3D-QSAR--from a point to surface sectors and molecular volumes

Shape analysis is a powerful tool in chemistry and drug design. In the current work, we compare the results of CoMFA and Comparative Molecular Surface Analysis (CoMSA), the 3D-QSAR method, for a series of hypolipidemic and antiplatelet asarones and antifungal N-myristoyltransferase inhibitors. In this publication we show that a sector CoMSA formalism enables an analysis of the biological activity that is more directly related to the molecular shape and individual molecular functionalities than the traditional uniform and directionless CoMFA field. Iterative Variable Elimination allowed us to identify the potential pharmacophoric sites. We modeled QSARs for both series and demonstrate that sector-based molecular descriptors give very predictive models and allow one to generate a spatial interpretation of the QSAR models. In particular, we identified the central aromatic ring and carbonyl functions as the moieties determining the activity of the asarones series, while the pattern of substitution of the aromatic ring determines the activity of N-myristoyltransferase inhibitors.