Justicidin E: A new leukotriene biosynthesis inhibitor

Pharmacological activities of the organic extracts and fatty acid composition of the petroleum ether extract from Haplophyllum tuberculatum leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Haplophyllum tuberculatum is used in traditional medicine to treat many disorders including inflammation and pain. The aim of this study is to investigate the organic extracts from H. tuberculatum leaves against inflammation, gastric ulcer and pain.

MATERIALS AND METHODS

Acute toxicity was studied in vivo to determine the toxic doses of the organic extracts. Anti-inflammatory activity was also evaluated in vivo using carrageenan-induced paw edema in Wistar rats. Gastroprotective activity was tested using the HCl/ethanol-induced gastric ulcer test in rats. Peripheral and central analgesic activities were assessed using the acetic acid-induced writhing test and the hot-plate method, respectively. The chemical composition of the fatty acids in the petroleum ether (PE) extract was determined with GC-MS.

RESULTS

At 25, 50 and 100mg/kg PE extract was the most active against inflammation. Percentages inhibition 5h after carrageenan-injection were 51.12; 86.71% and 96.92%, respectively. The same extract at 100mg/kg showed good analgesic activities using the acetic acid-induced writhing test and the hot-plate method. The chloroform, ethyl acetate (EtOAc) and butanolic (n-BuOH) extracts exhibited strong anti-inflammatory, gastroprotective and analgesic activities at 100mg/kg. The GC-FID analysis revealed that the PE extract was rich in γ-linolenic acid (45.50%) followed by palmitic acid (18.48%), linoleic acid (10.73%), erucic acid (4.72), stearic acid (3.96%) and oleic acid (2.57%).

CONCLUSION

The results of the present study support the traditional use of the leaves of H. tuberculatum and may possibly serve as prospective material for further development of safe new phytochemical anti-inflammatory, gastroprotective and/or analgesic agents.

Anti-Inflammatory and Antinociceptive Studies of Hydroalcoholic Extract from the Leaves of Phyllanthus brasiliensis (Aubl.) Poir. and Isolation of 5-O-β-d-Glucopyranosyljusticidin B and Six Other Lignans

The aim of this study was to investigate the chemical composition and the antiinflammatory/antinociceptive properties of the hydroalcoholic extract derived from the leaves of Phyllanthus brasiliensis (HEPB) in rodents. A new arylnaphthalene lignan glycoside, 5-O-β-d-glucopyranosyljusticidin B, together with six known lignans, were isolated from HEPB. 1D and 2D NMR experiments and HRMS were used to elucidate the structure of the new compound. HEPB toxicity and antinociceptive activity were evaluated through acute oral toxicity and formalin models in mice, respectively. The anti-inflammatory effects of HEPB were assessed using carrageenan- and dextran-induced paw edema models in rats. HEPB showed low toxicity. Oral administration of HEPB reduced paw edema induced by carrageenan, but not by dextran. HEPB and its fractions from FR6 to FR10 (FR6-10) inhibited the neurogenic and inflammatory phases of formalin-induced linking, demonstrating its antinociceptive activity. These results indicated that lignans from Phyllanthus brasiliensis exerted antinociceptive/anti-inflammatory effects not related to the histaminergic pathway.

Arylnaphthalene lactone analogues: synthesis and development as excellent biological candidates for future drug discovery

Arylnaphthalene lactones are natural products extracted from a wide range of different parts of plants. The progressing interest in the synthesis of these compounds is due to their significant biological activities, which have made them potential candidates in drug discovery and development. This review mainly covers recent developments in the synthesis and biological applications of arylnaphthalene lactone analogs.

A review of recent developments in the synthesis and biological applications of arylnaphthalene lactones analogs.

Deconjugative alkylation/Heck reaction as a simple platform for dihydronaphthalene synthesis

A simple platform for carbocycle synthesis by Knoevenagel adduct deconjugative alkylation/“pairing” reaction is described.

Glycosides of arylnaphthalene lignans from Acanthus mollis having axial chirality

Glycosides of arylnaphthalene lignans having axial chirality were isolated from Acanthus mollis. Owing to the axial chirality, their structure, including absolute configuration, was determined by means of extensive spectroscopic data such as UV, IR, MS, 1D and 2D NMR spectra, and computational chiroptical methods. A compound, 2',4-dihydroxyretrohelioxanthin (2'-hydroxy-justirumalin), has a structure containing two aromatic moieties with substituents hindering rotation about the biaryl axis. The aglycone was connected to a saccharide moiety linked at C-4 or C-2' and made up of one or four sugars (rhamnose or quinovose, and tetrasaccharide 4-O-beta-D-xylopyranosyl-(1'''''-6'')-O-[beta-D-rhamnopyranosyl-(1''''-3'')]-O-beta-D-apiofuranosyl-(1''''-2'')-O-beta-D-glucopyranoside and quinovose). Two mono- and one tetraglycoside gave positive results in the sea urchin eggs test (Paracentrotus lividus) of cytotoxicity and in a crown gall tumor on potato disks test (Agrobacterium tumefaciens).

Synthesis and Antiviral Activity of Helioxanthin Analogues

A series of natural product analogues based on helioxanthin (2), with particular attention to modification of the lactone ring and methylenedioxy group, were synthesized and evaluated for their antiviral activities. Among them, lactam derivative 18 and helioxanthin cyclic hydrazide 28 exhibited significant in vitro antiviral activity against hepatitis B virus (EC(50) = 0.08 and 0.03 microM, respectively). Compound 18 showed the most potent antiviral activity against hepatitis C virus (55% inhibition at 1.0 microM). Compound 12, an acid-hydrolyzed product of helioxanthin cyclic imide derivative 9, was found to exhibit broad-spectrum antiviral activity against hepatitis B virus (EC(50) = 0.8 microM), herpes simplex virus type 1 (EC(50) = 0.15 microM) and type 2 (EC(50) < 0.1 microM), Epstein-Barr virus (EC(50) = 9.0 microM), and cytomegalovirus (EC(50) = 0.45 microM). Helioxanthin lactam derivative 18 also showed marked inhibition of herpes simplex virus type 1 (EC(50) = 0.29 microM) and type 2 (EC(50) = 0.16 microM). The cyclic hydrazide derivative of helioxanthin 28 and its brominated product 42 exhibited moderately potent activities against human immunodeficiency virus (EC(50) = 2.7 and 2.5 microM, respectively). Collectively, these molecules represent a novel set of antiviral compounds with unique structural features.

Preparation and anti-HIV activities of retrojusticidin B analogs and azalignans

Ten lignans (2-11) and a series of azalignans including 1-aryl-pyrronaphthalenes 20-24 and 3-N-alkylaminomethyl-1-arylnaphthalenes 25-28, structurally related to two HIV reverse transcriptase inhibitors, retrojusticidin B and phyllamyricin A, were prepared from phyllanthin (1) for evaluation of anti-HIV activities. Anti-HIV activity of these compounds on a R5 pseudotype virus, ConB/pNL43E-L+, in the U87-CD4-CCR5 cells has been measured. Compounds 5, 22, 23, and 28 showed good anti-HIV activity with IC(50) value of 0.25, 1.07, 0.01, 0.32 microg/mL, respectively.

Dioxabicyclooctanyl naphthalenenitriles as nonredox 5-lipoxygenase inhibitors: structure-activity relationship study directed toward the improvement of metabolic stability

Naphthalenic lignan lactone 3a (L-702,539), a potent and selective 5-lipoxygenase (5-LO) inhibitor, is extensively metabolized at two different sites: the tetrahydropyran and the lactone rings. Early knowledge of the metabolic pathways triggered and directed a structure-activity relationship study aimed toward the improvement of metabolic stability in this series. The best modifications discovered, i.e., replacement of the lactone ring by a nitrile group, replacement of the tetrahydropyran ring by a 6,8-dioxabicyclo[3.2.1]octanyl moiety, and replacement of the pendant phenyl ring by a 3-furyl ring, were incorporated in a single molecule to produce inhibitor 9ac (L-708,780). Compound 9ac inhibits the oxidation of arachidonic acid to 5-hydroperoxy-eicosatetraenoic acid by 5-LO (IC50 = 190 nM) and the formation of leukotriene B4 in human polymorphonuclear leukocytes (IC50 = 3 nM) as well as in human whole blood (IC50 = 150 nM). The good inhibitory profile shown by naphthalenenitrile 9ac is accompanied by an improved resistance to oxidative metabolism. In addition, 9ac is orally active in the functional model of antigen-induced bronchoconstriction in allergic squirrel monkeys (95% inhibition at 0.1 mg/kg).