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PubMed2006

Sunscreen enhancement of UV-induced reactive oxygen species in the skin.

The number of UV-induced (20 mJ cm(-2)) reactive oxygen species (ROS) generated in nucleated epidermis is dependent upon the length of time the UV filter octocrylene, octylmethoxycinnamate, or benzophenone-3 remains on the skin surface. Two-photon fluorescence images acquired immediately after application of each formulation (2 mg cm(-2)) to the skin surface show that the number of ROS produced is dramatically reduced relative to the skin-UV filter control. After each UV filter remains on the skin surface for t=20 min, the number of ROS generated increases, although it remains below the number generated in the control. By t=60 min, the filters generate ROS above the control. The data show that when all three of the UV filters penetrate into the nucleated layers, the level of ROS increases above that produced naturally by epidermal chromophores under UV illumination.

Humans↗

PubMed2005

The effect of packaging materials on the stability of sunscreen emulsions.

The purpose of this research was to study the stability of a emulsion containing UVA, UVB and infrared sunscreens after storage in different types of packaging materials (glass and plastic flasks; plastic and metallic tubes). The samples, emulsions containing benzophenone-3 (B-3), octyl methoxycinnamate (OM) and Phycocorail, were stored at 10, 25, 35 and 45 degrees C and representative samples were analyzed after 2, 7, 30, 60 and 90 days period. The stability studies were conducted by analyzing samples at pre-determined intervals by high performance liquid chromatography (HPLC) along with periodic rheological measurements.

Chromatography, High Pressure Liquid↗

PubMed2004

Opacification of hydrophilic MemoryLens U940A intraocular lenses: analysis of 2 explanted lenses.

PURPOSE: To determine the rate of opacification of hydrophilic MemoryLens U940A intraocular lenses (IOLs) (Mentor Ophthalmics, Inc.) in the given cohort and perform a histopathological and spectrophotometer analysis of 2 explanted opacified IOLs. SETTING: Ophthalmology Department, Faculty Hospital, Nitra, Slovakia. METHOD: This retrospective study comprised 182 patients (205 eyes) who had implantation of a MemoryLens U940A IOL from June 1997 to June 2000. The patients were examined using a slitlamp to detect the presence of IOL opacification. In 4 cases, the lenses were explanted because of significant opacification and patient-reported problems; 2 lenses were provided for further analysis. One unused reference MemoryLens U940A IOL was also evaluated. All IOL were stained with von Kossa to determine the presence of calcium in the opacification. To confirm the components presence of an ultraviolet (UV) absorber, the IOLs were examined with an Avatar 330 Fourier transfer infrared (IR) spectroscope and a UV visible spectrophotometer (Philips). The IR spectrums for the IOL were identified using an IR spectrum atlas. The opacified IOLs, reference IOL, and the IOL packaging were further examined to determine the presence of silicone. RESULTS: Various amounts of opacification were found on the MemoryLens U940A IOL in 30 eyes (30 patients) (14.63%). Two explanted IOLs were positive for von Kossa staining, proving the presence of calcium deposits; the reference lens staining was negative. Spectrophotometry showed that the reference IOL and opacified IOLs were of the same polymer. The presence of the UV absorber on the benzophenone base was seen in the reference lens but not the opacified IOLs. In contrast, an increased concentration of low-molecular-weight components generated during the degradation of the polymer was present in the opacified lenses. The white cover pf the IOL is of polydimethyl siloxane, a silicone rubber. However, no silicone rubber was present in any examined lens, perhaps because the IOLs were in contact with alcohol during the histopathologic examination. CONCLUSIONS: The results indicate opacification of the hydrophilic MemoryLens U940A was caused by premature consumption of the UV absorber in the polymer component of the IOLs optic, with a subsequent degradation of the polymer. Whether silicone from the white cover led to the IOL opacification, as reported with other types of hydrophilic IOLs, could not be confirmed.

Aged↗

PubMed2005

The influence of N-dialkyl and other cationic substituents on DNA intercalation and genotoxicity.

DNA intercalation by small chemical molecules can result in frameshift mutagenesis and chromosomal breakage. With evidence mounting that broadly diverse structures are capable of intercalating between DNA base pairs, it becomes important to better define those structural features that enhance intercalation strength and those that confer genotoxicity particularly among those intercalators that do not have the classical planar tricyclic fused ring structure. A chemical substituent that is present on many pharmaceutical and other biologically active molecules is the N-dialkyl group. In the present study, we investigate if and how the presence of an aromatic N-dialkyl or other cationic group affects the genotoxicity and DNA intercalation ability of 26 selected acridines, phenothiazines, benzophenones, triphenylethylenes and other classes of molecules. The data were obtained from the literature, from experiments using a cell-based DNA intercalation assay, and from modeling studies using a three-dimensional computational DNA docking program. It is demonstrated that cationic substitution can enhance both genotoxicity and electrostatic interactions within a chemical/DNA intercalation complex.

Animals↗

PubMed2005

Antimicrobial activity of isoprenoid-substituted xanthones from Cudrania cochinchinensis against vancomycin-resistant enterococci.

Ten xanthones with one or two isoprenoid groups and a prenylated benzophenone isolated from roots of Cudrania cochinchinensis (Moraceae) were tested for their antimicrobial activities against vancomycin-resistant enterococci (VRE). Among these compounds, gerontoxanthone H exhibited considerable antibacterial activity against five VRE strains (VanA, VanB and VanC) (MICs = 1.56 microg/ml). Four xanthones, 1,3,7-trihydroxy-2-prenylxanthone, gerontoxanthone I, alvaxanthone and isoalvaxanthone, showed weaker antibacterial activity against these VREs (MICs = 3.13-6.25 microg/ml). .

Anti-Bacterial Agents↗

PubMed2005

Biosynthesis of the hyperforin skeleton in Hypericum calycinum cell cultures.

Hyperforin is an important antidepressant constituent of Hypericum perforatum (St. John's wort). Cell cultures of the related species H. calycinum were found to contain the homologue adhyperforin and to a low extent hyperforin, when grown in BDS medium in the dark. Adhyperforin formation paralleled cell culture growth. Cell-free extracts from the cell cultures contained isobutyrophenone synthase activity catalyzing the condensation of isobutyryl-CoA with three molecules of malonyl-CoA to give phlorisobutyrophenone, i.e. the hyperforin skeleton. The formation of the hyperforins during cell culture growth was preceded by an increase in isobutyrophenone synthase activity. The cell cultures also contained benzophenone synthase and chalcone synthase activities which are involved in xanthone and flavonoid biosyntheses, respectively. The three type III polyketide synthases were separated by anion exchange chromatography.

Acyltransferases↗

PubMed2005

Prenylated anthronoid antioxidants from the stem bark of Harungana madagascariensis.

Two new prenylated anthronoids, harunmadagascarins A and B, were isolated from the stem bark of Harungana madagascariensis along with six known compounds including two anthronoids: harunganol B and harungin anthrone, one benzophenone: methyl 3-formyl-2,4-dihydroxy-6-methyl benzoate and three pentacyclic triterpenes: friedelin, lupeol and betulinic acid. Harunmadagascarins A and B were characterized as 8,9-dihydroxy-4,4-bis-(3,3-dimethylallyl)-6-methyl-2,3-(2,2-dimethylpyrano)anthrone and 8,9-dihydroxy-4,4,5-tris-(3,3-dimethylallyl)-6-methyl-2,3-(2,2-dimethylpyrano)anthrone, respectively. The structures of these secondary metabolites were determined by spectroscopic means and comparison with the published data. Methyl 3-formyl-2,4-dihydroxy-6-methyl benzoate was isolated for the first time from a plant. Harunmadagascarins A and B, harunganol B and harungin anthrone exhibited significant antioxidant activity.

Anthracenes↗

PubMed2004

Endocrine activity and developmental toxicity of cosmetic UV filters--an update.

UV filters represent a new class of endocrine active chemicals. In vitro, 8/9 chemicals showed estrogenic (MCF-7 cells), and 2/9 antiandrogenic activity (MDA-kb2 cells). Six/nine filters (benzophenone (Bp)-1, Bp-2, Bp-3, 3-benzylidene camphor (3-BC), 4-methylbenzylidene camphor (4-MBC), octyl-methoxycinnamate (OMC)) increased uterine weight in immature rats. 3-Benzylidene camphor and 4-MBC displaced 16alpha125I-estradiol from human estrogen receptor (ER)beta, not ERalpha. Developmental toxicity of 4-MBC (0.7-47 mg/kg body weight/day) and 3-BC (0.24-7 mg/kg), administered in chow was investigated in Long Evans (LE) rats. Weight gain of pregnant rats was reduced only by 3-BC, early postnatal survival rate and thymus weight by both compounds at higher doses. 4-Methylbenzylidene camphor and 3-BC delayed male puberty, and dose-dependently affected reproductive organ weights of adult male and female F1 offspring, with partly different effect patterns. Thyroid weight was increased by higher 4-MBC doses. Tissue-specific changes in mRNA levels of estrogen-regulated genes in prostate, uterus and brain regions, determined by real-time PCR, and in their response to acute estradiol challenge in adult gonadectomized offspring were observed. Lowest effective doses were 0.24 mg/kg/day for 3-BC and 7 mg/kg/day for 4-MBC. Fat tissue levels at 7 mg/kg 4-MBC (GC-MS) approached the range of UV filters in fish (Nagtegaal et al., 1997; Balmer et al., 2004).

Animals↗

PubMed2006

Adenoviral gene vector tethering to nanoparticle surfaces results in receptor-independent cell entry and increased transgene expression.

The present studies investigated the hypothesis that affinity immobilization of replication-defective adenoviruses (Ad) on the surfaces of biodegradable nanoparticles (NP) can improve transduction through uncoupling cellular uptake from the coxsackie-adenovirus receptor (CAR). Ad was tethered to the surfaces of polylactide-based NP that were surface-activated using a photoreactive polyallylamine-benzophenone-pyridyldithiocarboxylate polymer, which enabled (via thiol chemistry) the covalent attachment of Ad-binding proteins, either the recombinant D1 domain of CAR or an adenoviral knob-specific monoclonal antibody. Gene transfer by NP-Ad complexes was studied in relation to cellular uptake as a function of cell type and the character of NP-Ad binding. NP-Ad complexes, but not Ad applied with or without control nonimmune IgG-modified NP, significantly increased green fluorescent protein reporter expression in endothelioma and endothelial and arterial smooth muscle cells (SMC) in direct correlation to the extent of NP-Ad internalization. CAR-independent uptake of NP-Ad was confirmed by demonstrating inhibition of free Ad- but not NP-Ad complex-mediated transduction by knob protein. Complexes formulated with an Ad encoding inducible nitric oxide synthase inhibited growth of cultured SMC to a significantly greater extent than those with (GFP)Ad or (NULL)Ad or free vector. It is concluded that Ad-specific affinity tethering to biodegradable NP can significantly increase the level of gene expression via a CAR-independent uptake mechanism.

Adenoviridae↗

PubMed2002

Fate of excited probes in micellar systems.

This article presents studies on the photophysical and photochemical behavior of probes within micellar systems: organized emulsifier/polymer aggregates; the intra- and interpolymer association of amphiphilic polymers; monomer-swollen micelles (microdroplets); and the interfacial layer. Pyrene (Py) as a probe is particularly attractive because of its ability to measure the polarity of its microenvironment. Dipyme yields information on the microviscosity of micellar systems. Probes such as laurdan and prodan can be used to explore the surface characteristics of micelles or microdroplets. The dansyl group has a special photophysical property that gives information about the local polarity and mobility (viscosity) of the microenvironment. The organized association of amphiphilic polymer and emulsifier introduces a heterogeneity in the local concentration of the reactants. This heterogeneity also results from the attractive interaction between hydrophilic monomer and emulsifier in the case when the monomer carries a positive charge and the counterpart a negative one, and vice versa. Some emulsifiers can bind to the amphiphilic copolymers by simple partitioning between the aqueous phase and the polymer--non-cooperative association. The interaction between micelles (microdroplets) and charged polymers leads to the formation of mixed micelles. Binding emulsifiers to these polymers was detected at emulsifier concentrations much below the critical micellar concentration (CMC). Emulsifiers often interact cooperatively with polymers at the critical aggregation concentration (CAC) below the CMC, forming micelle-like aggregates within the polymer. The CAC can be taken as a measure of interaction between the emulsifier and polymer. A decrease in the monomer fluorescence intensity of probe-labeled polymer results from increased excimer formation, or higher aggregates within the unimolecular polymeric micelles. An increase in the monomer fluorescence intensity of probe-labeled polymer within the micellar system can be ascribed to shielding of the probe chromophores by emulsifier micelles. The quenching of probe emission by (un)charged hydrophilic monomer depends on partitioning of the monomer between the aqueous phase and the micelles. Penetration of reactants into the interfacial layer determines the quenching of the hydrophobic probe by hydrophilic quencher, or vice versa. Quenching depends on the thickness, density and charge of the interfacial layer. Compartmentalization prevents the carbonyl compound and unsaturated monomer from coming into sufficiently close contact to allow singlet or triplet-monomer interaction. All negatively charged carbonyl probe molecules are quenched with significantly lower rates than the parent neutral hydrophobic benzophenone molecules, which were located further inside the aggregates. This results from the different conformation and allocation of reactants within the micellar system. In the reverse micelles, quenching depends on the amount of water in the interfacial layer and the total area of the water/oil interface.

Journal Article↗

PubMed1997

The efficiency of antioxidants delivered by liposomal transfer.

Phenolic antioxidants of the hydroxychroman class, alpha-tocopherol (alpha-TOC) and 2,2,5,6,7-pentamethyl-6-hydroxychroman (PMHC), and the hindered phenols 2,3-dihydro-5-hydroxy-2,2,4-trimethylnaphtho[1,2-b]furan (NFUR), 2,6-di-tert-butyl-4-methoxyphenol (DBHA), and 2,6-di-tert-butyl-4-methyl phenol (BHT), were delivered into oxidizable (ACCEPTOR) liposomes of dilinoleoylphosphatidylcholine (DLPC) or 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC) from saturated DONOR liposomes of dimyristoylphosphatidylcholine (DMPC) by liposomal transfer. The antioxidant activities, k(inh), by the inhibited oxygen uptake method were compared with the k(inh)s determined when the antioxidants were introduced into the liposomes by coevaporation from organic solvents. The peroxidations were initiated using either thermal initiators, water-soluble azo-bis-amidinopropane hydrochloride (ABAP), lipid-soluble azo-bis-2,4-dimethylvaleronitrile (ADVN) and di-tert-butylhyponitrite (DBHN), or the photoinitiator benzophenone. The antioxidants PMHC, NFUR, DBHA, and BHT transferred rapidly between liposomes, but several hours of incubation were needed to transfer alpha-TOC. The average k(inh)s in liposomes, in the relative order NFUR approximately DBHA > PMHC > BHT approximately alpha-TOC, were markedly lower than known values in organic solvent. k(inh) values in liposomes appear to be controlled by effects of hydrogen bonding with water and by restricted diffusion of antioxidants, especially in the case of alpha-TOC. Product studies of the hydroperoxides formed during inhibited oxygen consumption were carried out. The cis,trans/trans,trans (c,t/t,t) product ratios of the 9- and 13-hydroperoxides formed from PLPC during inhibited peroxidation by PMHC were similar for both the coevaporated and liposomal transfer procedures. The c,t/t,t ratio for the same concentration of alpha-TOC, 1.52, compares to a value of 1.69 for PMHC at the start of the inhibition period. The higher c,t/t,t ratio observed for NFUR in DLPC, which varied between values of 7.0 at the start of the inhibition to about 1.8 after the break in the induction period, is a reflection of the increased hydrogen atom donating ability of the antioxidant plus the increased concentration of oxidizable lipid provided by DLPC.

Amidines↗

PubMed1995

Functional significance of a protein conformation change at the cytoplasmic end of helix F during the bacteriorhodopsin photocycle.

The second half of the photocycle of the light-driven proton pump bacteriorhodopsin includes proton transfers between D96 and the retinal Schiff base (the M to N reaction) and between the cytoplasmic surface and D96 (decay of the N intermediate). The inhibitory effects of decreased water activity and increased hydrostatic pressure have suggested that a conformational change resulting in greater hydration of the cytoplasmic region is required for proton transfer from D96 to the Schiff base, and have raised the possibility that the reversal of this process might be required for the subsequent reprotonation of D96 from the cytoplasmic surface. Tilt of the cytoplasmic end of helix F has been suggested by electron diffraction of the M intermediate. Introduction of bulky groups, such as various maleimide labels, to engineered cysteines at the cytoplasmic ends of helices A, B, C, E, and G produce only minor perturbation of the decays of M and N, but major changes in these reactions when the label is linked to helix F. In these samples the reprotonation of the Schiff base is accelerated and the reprotonation of D96 is strongly retarded. Cross-linking with benzophenone introduced at this location, but not at the others, causes the opposite change: the reprotonation of the Schiff base is greatly slowed while the reprotonation of D96 is accelerated. We conclude that, consistent with the structure from diffraction, the proton transfers in the second half of the photocycle are facilitated by motion of the cytoplasmic end of helix F, first away from the center of the protein and then back.

Bacteriorhodopsins↗

PubMed2000

Antioxidative effects of green tea polyphenols on free radical initiated and photosensitized peroxidation of human low density lipoprotein.

Antioxidative effects of the main polyphenolic components extracted from green tea leaves, i.e. (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG) and gallic acid (GA), against free radical initiated peroxidation of human low density lipoprotein (LDL) were studied. The peroxidation was initiated either thermally by a water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), or photochemically by a triplet sensitizer benzophenone (BP). The reaction kinetics was monitored by the uptake of oxygen and the depletion of alpha-tocopherol (TOH) presented in the native LDL. Kinetic analysis of the antioxidation process demonstrates that these green tea polyphenols are effective antioxidants against both AAPH-initiated and BP-photosensitized LDL peroxidation. The antioxidative action of the green tea polyphenols includes trapping the initiating and/or propagating peroxyl radicals with the activity sequence EC>EGCG>ECG>EGC>GA for the AAPH initiated peroxidation, and reducing the alpha-tocopheroxyl radical to regenerate alpha-tocopherol with the activity sequence of ECG>EC>EGCG>EGC>GA and ECG>EGCG>GA>EC>EGC for the AAPH-initiated and BP-photosensitized peroxidations respectively.

Antioxidants↗

PubMed1975

The measurement of Rivotril in whole blood by gas liquid chromatography.

Rivotril is extracted from blood into an organic solvent mixture, Mogadon, (Nitrazepam) is used as internal standard. The drugs are then back-extracted into acid which is heated to produce the corresponding benzophenones. These are extracted into benzene and separated by gas liquid chromatography with electron capture detection.

Benzodiazepinones↗

PubMed1999

Smooth muscle alpha-tropomyosin crosslinks to caldesmon, to actin and to myosin subfragment 1 on the muscle thin filament.

To obtain proximity information between tropomyosin (Tm) and caldesmon (CaD) on the muscle thin filament, we cloned gizzard alphaTm and created two single Cys mutants S56C/C190S (56Tm) and D100C/C190S (100Tm). They were labeled with benzophenone maleimide (BPM) and UV-irradiated on thin filaments. One chain of BPM-56Tm and two chains of BPM-100Tm crosslinked to CaD. Only BPM-100Tm crosslinked to actin in the absence and presence of CaD and binding of low ratios of myosin subfragment 1 (S1) prevented the crosslinking. Tm-S1 crosslinks were produced when actin.Tm was saturated with S1. Thus, CaD on the actin.Tm filament is located <10 A away from Tm amino acids 56 and 100; in the closed state of the actin.Tm filament, Tm residue 100 is located close to the actin surface and is moved further away in the S1-induced open state; in the open state, S1 binds close to Tm.

Actins↗

PubMed2001

Improvement of the synthesis of diphenylmethyl 7beta-(o-hydroxy)benzylideneamino-3-hydroxymethyl-3-cephem-4-carboxylate.

The title product (I) is synthesized currently from 7-aminocephalosporanic acid, and diphenyldiazomethane (DDM) is used as a protective reagent of the acid function for further reactions. When DDM was prepared from benzophenone hydrazone by reaction with chloramine T, it was resulted impure by p-toluenesulfonamide, formed as side product, which cannot be removed during the final purification step carried out according to the literature procedure. Two simple methods are proposed here to obtain I with the suitable degree of purity necessary for a drug.

Benzene↗

PubMed2001

Molecularly imprinted polymer membranes for substance-selective solid-phase extraction from water by surface photo-grafting polymerization.

Hydrophilized polyvinylidene fluoride microfiltration membranes were surface-modified in the presence of a template (terbumeton) in methanol with a graft copolymer of a functional monomer (2-acrylamido-2-methyl-1-propane sulfonic acid, AMPS, methacrylic acid, MAA, or acrylic acid, AA) and a cross-linker (N,N'-methylene-bis-acrylamide) using UV irradiation and benzophenone as photoinitiator. As result, membranes covered with a thin layer of imprinted polymer selective to terbumeton were obtained. Blank membranes were prepared with the same monomer composition, but in the absence of the template. The membranes' capacity to adsorb terbumetone from aqueous solution was evaluated yielding information regarding the effect of polymer synthesis (type and concentration of functional monomer, concentration of cross-linker) on the resulting membranes' recognition properties. UV spectroscopic studies of the interactions with terbumetone revealed that AMPS forms a stronger complex than MAA and AA. In agreement with that finding, imprinting with AMPS gave higher affinities than with MAA and AA. The terbumeton-imprinted membranes showed significantly higher sorption capability to this herbicide than to similar compounds (atrazine, desmetryn, metribuzine). With the novel surface modification technology, the low non-specific binding properties of the hydrophilized microfiltration membrane could successfully be combined with the receptor properties of molecular imprints, yielding substance-specific molecularly imprinted polymer composite membranes. The high affinity of these synthetic affinity membranes to triazine herbicides together with their straightforward and inexpensive preparation provides a good basis for the development of applications of imprinted polymers in separation processes such as solid-phase extraction.

Membranes, Artificial↗

PubMed1978

Thin-layer detection of diazepam and/or chilordiazepoxide alone or in combination with major drugs of abuse in drug abuse urine screening programs.

Three extraction procedures for the detection of diazepam, oxazepam, chlorazepate and/or chlordiazepoxide in human urines are presented. All three procedures are based on the acid hydrolysis of benzodiazepines and/or their conjugated metabolites to give the corresponding benzophenones. Procedure I involves the direct acid hydrolysis of raw urine and is recommended when the aim is to test the abuse of benzodiazepine derivatives only. Procedure II Is a two-step extraction method in which a wide variety of drugs of abuse including cocaine (test based on the detection of benzoylecgonine) are extracted by the first step using paper loaded with cation-exchange resin and the benzodiazepines are tested in the second step by the acid hydrolysis of the spent urine left after removing the ion-exchange paper. Procedure III involves the use of inert fibrous matrix and then its acid hydrolysis. The detection procedure is based on the identification of methylaminochlorobenzophenone (MACB) and aminochlorobenzophenone (ACB). MACB is detected as a yellow-colored compound while ACB is detected by spraying with Bratton-Marshall reagent. Specificity of detection of ACB has been achieved by the selection of a thin-layer developing solvent system in which sulfonamides with primary aromatic amino groups remain at the origin.

Chlordiazepoxide↗