Phytochemical and genetic characterization of styles of wild Crocus species from the island of Crete, Greece and comparison to those of cultivated C. sativus.

The aim of this study was to contribute to the characterization of Crocus taxa using morphological, phytochemical and genetic analysis. The styles of C. cartwrightianus, C. oreocreticus and C. laevigatus, collected in the island of Crete were compared to those of C. sativus cultivated at the region of Western Macedonia (Greece). Phytochemical analysis was done using GC-MS and HPLC methods, while ISSR markers were used for their genetic characterization. Safranal was the major volatile component of the styles of C. sativus, 4-hydroxy-2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde of C. cartwrightianus and C. oreocreticus, and isophorone of C. laevigatus. C. sativus had the highest content of crocins and picrocrocin, while C. laevigatus the lowest (only 5% of C. sativus' quantity) and negligible amount of picrocrocin. According to both the genetic and the chemical analysis, C. cartwrightianus is more related to C. oreocreticus, while C. sativus and C. laevigatus are more distinct. Concordance between the two different types of data was also confirmed by the Mantel test (r = 0.932, P = .68). This is the first thorough screening of secondary metabolites (volatile and non-volatile) and also genetic and morphological characters of wild Crocus styles simultaneously, that contributes to the identification and valorisation of genotypes with similar to C. sativus traits which may be introduced as new cultivars through breeding.

Synthesis and biological evaluation of new C-10 substituted dithranol pleiotropic hybrids.

Selective alkylation of the antipsoriatic drug dithranol (DTR) at C-10 with tert-butyl bromoacetate, followed by acid-mediated deprotection, produced the corresponding carboxylic acid 4 which was coupled with selectively protected polyamines (PAs), such as putrescine (PUT), spermidine (SPD) and spermine (SPM), dopamine and aliphatic amines and substituted benzylamines producing a series of DTR-PA hybrids, after acid-mediated deprotection, as well as simple amides. The compounds were tested as antioxidants and inhibitors of lipoxygenase (LOX). The amides 4,4'-dimethoxybenzhydrylamide 13 (86% and 95%), 2,4-dimethoxybenzylamide 12 (87% and 81%) and dodecylamide 9 (98% and 74%), and the hybrid DTR-SPM (7) (93% and 87%), showed the highest antioxidant activity in the DPPH and AAPH assays, whereas the most potent inhibitors of LOX were amide 13 (IC50=7 µM), the benzylamide 10 (IC50=7.9 µM) and the butylamide 8 (IC50=10 µM). Molecular binding studies showed that binding of these derivatives into the hydrophobic domain blocks approach of substrate to the active site, inhibiting soybean LOX. Amide 13 presented the highest anti-inflammatory activity (79.7%). The DTR moiety was absolutely necessary for securing high anti-inflammatory potency. Ethyl ester 3 (IC50=0.357 µM) and the amides 9 (IC50=0.022 µM) and 13 (IC50=0.56 µM) exhibited higher antiproliferative activity than DTR (IC50=0.945 µM) on HaCaT keratinocytes whereas amide 13 generally presented better cytocompatibility. Amide 13 is a very promising lead compound for further development as an anti-inflammatory and antiproliferative agent.

Synthesis and evaluation of the antioxidative potential of minoxidil-polyamine conjugates.

A series of conjugates (MNX-CO-PA) of minoxidil (MNX) with the polyamines (PAs) putrescine (PUT), spermidine (SPD) and spermine (SPM) as well as dopamine were produced through activation of MNX with N,N'-carbonyldiimidazole, followed by reaction with dopamine or selectively protected PAs and acid-mediated deprotection. These conjugates together with conjugates of the general type MNX-PA or PA-MNX-PA, readily produced using literature protocols, were tested as antioxidants. The most potent inhibitors of lipid peroxidation were the conjugates MNX-SPM (2, 94%), SPM-MNX-SPM (4, 94%) and MNX-N(4)-SPD (7, 91%) and MNX (91%). The most powerful lipoxygenase (LOX) inhibitors were MNX (IC50 = 20 µM) and the conjugates MNX-N(8)-SPD (9, IC50 = 22.1 µM), MNX-CO-dopamine (11, IC50 = 28 µM) and MNX-N(1)-SPD (8, IC50 = 30 µM). The most interesting conjugates 2, MNX-CO-PUT (5), 8 and 11 as well as MNX were generally found to exhibit weaker (22-36.5%) or no (conjugate 8) anti-inflammatory activity than indomethacin (47%) with the exception of MNX which showed almost equal potency (49%) to indomethacin. The cytocompatibility of conjugates and MNX at the highest concentration of 100 µM showed a survival percentage of 87-107%, with the exception of conjugates with SPM (compound 2) and MNX-CO-SPM (6), which showed considerable cytotoxicity (survival percentage 8-14%). Molecular docking studies were carried on conjugate 9 and the parent compound MNX and were found to be in accordance with our experimental biological results.

Syntheses and evaluation of the antioxidant activity of novel methoxypsoralen derivatives.

A series of 5- and 8-methoxypsoralen (MOP) analogs, suitable for structure-antioxidative/anti-inflammatory activity relationship studies, were synthesized using as key-reactions the selective monobromination of MOPs with N-bromosaccharin and either a Heck reaction or a Suzuki coupling or a Suzuki coupling followed by a Wittig reaction to install side-chains of the acrylate- or benzoate- or cinnamate-type, respectively. The 8-MOP analogs 19 and 24, incorporating at position 5 of the psoralen nucleus a butyl acrylate or a tert-butyl cinnamate moiety, were the most powerful inhibitors of soybean LOX and inhibited effectively lipid peroxidation. Analog 19 was a more potent anti-inflammatory agent than the reference compound indomethacin and of comparable cytocompatibility to 8-MOP whereas analog 24 was a weaker inhibitor of inflammation than indomethacin and significantly more cytotoxic than 8-MOP. The results of the biological tests are discussed in terms of structural characteristics.

Effect of an all-trans-retinoic acid conjugate with spermine on viability of human prostate cancer and endothelial cells in vitro and angiogenesis in vivo.

Retinoids constitute a family of organic compounds that are being used for the treatment of various diseases, ranging from acne vulgaris to acute promyelocytic leukemia. Their use however is limited due to serious adverse effects and there is a great need for analogues with better safety profile. In the present work, the effect of N(1),N(12)-bis(all-trans-retinoyl)spermine (RASP), a conjugate of all-trans-retinoic acid (atRA) with spermine, on angiogenesis in vivo and viability of human endothelial and prostate cancer cells in vitro were studied. Both atRA and RASP dose-dependently inhibited angiogenesis in the chicken embryo chorioallantoic membrane model. RASP was more effective and could be used in a wider dose range due to lower toxicity compared with atRA. Both retinoids decreased the number of human umbilical vein endothelial and prostate cancer LNCaP and PC3 cells in a concentration-dependent manner. RASP was more effective and potent compared with atRA, spermine, their combination, or conjugates of spermine with other acidic retinoids and/or psoralens in prostate cancer cells. The inhibitory effect of both atRA and RASP seems to be related to an increase of the tumour repressing gene retinoic acid receptor beta mRNA, was mediated by retinoic acid receptor alpha, and was proportional to endogenous retinoic acid receptor beta expression. These data suggest that RASP is more effective than atRA in decreasing angiogenesis and prostate cancer cell growth and identify retinoic acid receptor alpha as the receptor through which it causes retinoic acid receptor beta up-regulation and decrease of prostate cancer cell growth.

Syntheses, antiproliferative activity and theoretical characterization of acitretin-type retinoids with changes in the lipophilic part.

Acitretin analogs, incorporating changes in the lipophilic part, were efficiently synthesized from commercially available aromatic aldehydes or methyl ketones using the Wittig or Horner-Wadsworth-Emmons reaction. Their antiproliferative activity was evaluated against human breast MCF-7 epithelial cells. Analogs 3, 4, 8 and 11 exhibited strong, dose-dependent, antiproliferative activity on the tested cell line. Analog 3, incorporating three methoxy groups in the aromatic ring, exhibited the strongest inhibitory effect at 10 µM. High-level all electron conventional ab initio and density functional theory quantum chemical calculations were performed to obtain the molecular structure, electron charge distribution and polarization properties of all compounds of interest in this work. The most active analogs were planar and were characterized by larger dipole moments than the other synthesized molecules. Another factor of importance to the analysis of the activity of these molecules is the dipole polarizability.

Does conjugation of antioxidants improve their antioxidative/anti-inflammatory potential?

A series of symmetric and asymmetric spermine (SPM) conjugates with all-trans-retinoic acid (ATRA), acitretin (ACI), (E)-3-(trioxsalen-4'-yl)acrylic acid (TRAA) and L-DOPA, amides of ACI, l-DOPA and TRAA with 1-aminobutane, benzylamine, dopamine and 1,12-diaminobutane as well as hybrid conjugates of O,O'-dimethylcaffeic acid (DMCA) with TRAA or N-fumaroyl-indole-3-carboxanilide (FICA) and 2-(2-aminoethoxy)ethanol were synthesized and their antioxidant properties were studied. The reducing activity (RA)% of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging assay and found to be in the range 0-92(20 min)%/96(60 min)% at 100µM, the most powerful being the conjugates L-DOPA-SPM-L-DOPA (8, RA=89%/96%) and L-DOPA-dopamine (13, RA=92%/92%). Conjugate DMCA-NH(CH2CH2O)2-FICA (14) was the most powerful LOX inhibitor with IC50 33.5µM, followed by the conjugates ACI-NHCH2Ph (10, IC50 40.5µM), ACI-SPM-TRAA (7, IC50 41.5µM), DMCA-NH(CH2CH2O)2-TRAA (15, IC50 65µM), 13 (IC50 81.5µM) and ACI-dopamine (11, IC50 87µM). The most potent inhibitors of lipid peroxidation at 100µM were the conjugates 15 (98%) and ACI-SPM-ACI (4, 97%) whereas all other compounds showed activities comparable or lower than trolox. The most interesting compounds, namely ATRA-SPM-ATRA (3), 4, 10, 11 and 15, as well as unconjugated compounds such as ATRA and dopamine, were studied for their anti-inflammatory activity in vivo on rat paw oedema induced by Carrageenan and found to exhibit, for doses of 0.01 mmol/mL of conjugates per Kg of rat body weight, weaker anti-inflammatory activities (3.6-40%) than indomethacin (47%) with conjugate 3 being the most potent (40%) in this series of compounds. The cytocompatibility of selected compounds was evaluated by the viability of RAMEC cells in the presence of different concentrations (0.5-50µM) of the compounds. Conjugates 3 (IC50 2.6µM) and 4 (IC50 4.7µM) were more cytotoxic than the corresponding unconjugated retinoids ATRA (IC50 18.3µM) and ACI (IC50 14.6µM), whereas conjugate 15 (IC50 12.9µM) was less cytotoxic than either DCSP (IC50 11.3µM) or the tert-butyl ester of TRAA (IC50 2.9µM).

(2E,4E,6E)-3-Methyl-7-(pyren-1-yl)octa-2,4,6-trienoic acid.

The title compound, C(25)H(20)O(2), was synthesized by a Wittig reaction between triphen-yl[1-(pyren-1-yl)eth-yl]phospho-nium bromide and ethyl (2E,4E)-3-methyl-6-oxohexa-2,4-dienoate, in the presence of n-butyl lithium, followed by saponification. It was obtained pure in the all-trans configuration following crystallization from ethyl acetate. The asymmetric unit contains two independent mol-ecules (A and B), which are arranged almost parallel to each other within the crystal structure. The triene chain is not coplanar with the pyrene ring system, forming dihedral angles of 52.8 (1) and 42.2 (1)° for mol-ecules A and B, respectively. Inter-molecular hydrogen bonds between the carboxyl groups of the mol-ecules link them into centrosymmetric pairs, AA and BB, each with the R(2) (2)(8) graph-set motif.