Discovery of novel dehydroabietic acid derivatives as DNA/BSA binding and anticancer agents.

To explore the biological properties of rosin derivatives, two dehydroabietic acid derivatives N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2-carboxamide (DTPC) and di-N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2,6-carboxamide (DDTPC) with 1,3,4-thiadiazole, pyridine and amide moieties were designed and synthesized according to superposition principle of activity group. They interact with calf thymus DNA (CT DNA) via intercalation based on the results of circular dichroism (CD) and fluorescence spectroscopy, DNA denaturation and viscosity studies. Fluorescence and CD spectral experiments indicate that they might be transported and stored by protein like bovine serum albumin (BSA). MTT assay was further carried out to examine their cytotoxicity, they both showed selective cytotoxicity and DTPC exhibited better cytotoxicity. The antiproliferative effect of DTPC toward A431 cell line was stronger than that of clinically used cisplatin and oxaliplatin. In addition, the cytotoxicity of DTPC and DDTPC was closely related with their DNA binding ability.

Chemical Components from Aloe and their Inhibition of Indoleamine 2, 3-dioxygenase.

BACKGROUND: In Korea, Aloe is routinely ingested as a traditional medicine or as a component of health beverages. OBJECTIVE: To research the inhibition of indoleamine 2, 3-dioxygenase (IDO) activities of components from Aloe. MATERIALS AND METHODS: the compounds were isolated by a combination of silica gel and YMC Rp-18 column chromatography, and their structures were identified by analysis of spectroscopic data (1D, 2D-NMR, and MS). All of the isolated compounds were examined for their ability to inhibit IDO, which actively suppresses immune functions by catalyzing the rate limiting reaction in the conversion of tryptophan to kynurenine. RESULTS: In this phytochemical study, 18 known compounds were isolated from aqueous dissolved Aloe exudates. All of the isolated compounds were examined for their ability to inhibit IDO activities for a series of anthraquinone derivatives (1-7) isolated from the Aloe extract; the IC50 values of these compounds ranged from 39.41 to 53.93 µM. Enzyme kinetic studies of their modes of inhibition indicated that all of the compounds were uncompetitive inhibitors. CONCLUSION: The aqueous dissolved Aloe exudate can be used as a source of novel natural IDO inhibitors and merit testing as therapeutic agents in the treatments of cancer and immunopathologic diseases, such as autoimmune, inflammatory, and allergic disorders. SUMMARY: In this study, 18 known compounds were isolated from aqueous dissolved Aloe exudates. All of the isolated compounds were examined for their ability to inhibit indoleamine 2, 3-dioxygenase (IDO) activities for a series of anthraquinone derivatives (1-7) isolated from the Aloe extract. Abbreviation used: IDO: inhibit indoleamine 2, 3-dioxygenase, TMS: tetramethylsilane, HMQC: heteronuclear multiple quantum correlation, HMBC: heteronuclear multiple bond correlation, COSY: 1H-1H correlation spectroscopy, ESI-MS: Electrospray ionization mass spectrometry, DMSO: dimethyl sulfoxide.

ARGONAUTE SUBFAMILY GENES IN THE SMALL BROWN PLANTHOPPER, Laodelphax striatellus (HEMIPTERA: DELPHACIDAE).

Argonaute (AGO) proteins are essential catalytic components of the RNA-induced silencing complex and play central roles in RNA interference. Using a combination of bioinformatics and rapid amplification of cDNA ends (RACE) methods, putative AGO subfamily members, ls-AGO1 and ls-AGO2, were cloned and characterized from the small brown planthopper, Laodelphax striatellus. The open reading frame (ORF) of ls-AGO1 is 2,820 bp long, encoding a putative protein of 939 amino acid residues, and ls-AGO2 contains an ORF of 2,490 bp, encoding 829 amino acid residues. The expected conserved PAZ and PIWI domains, and the conserved Asp-Asp-His (DDH) catalytic triad motif in the PIWI domain were observed in both ls-AGO1 and ls-AGO2. Reverse transcription-qPCR (RT-qPCR) results showed that both ls-AGO1 and ls-AGO2 were expressed in all developmental stages of L. striatellus with highest mRNA abundance in eggs. Expression of ls-AGO1 and ls-AGO2 was significantly decreased in adult insects in response to acquisition of rice black-streaked dwarf virus by second instar nymphs. mRNA expression of ls-AGO1 was significantly downregulated in response to low and high temperatures, but expression of ls-AGO2 was only affected by low temperature. ls-AGO1 and ls-AGO2 were initially downregulated when insects were transferred from rice to maize and to the wild grass Brachypodium distachyon, but expression showed partial or complete recovery 7 days after transfer. These results document that AGO subfamily members of L. striatellus are ubiquitously expressed at different developmental stages and respond to various stresses. Thus, AGO subfamily may act in regulating the stress-response of L. striatellus by controlling related gene expression.

Triterpenoids isolated from the rhizomes and roots of Gentiana scabra and their inhibition of indoleamine 2,3-dioxygenase.

Gentiana scabra Bunge (Gentianaceae) is an important traditional Chinese medicine commonly used as a stomachic or appetite stimulant. In this study, 21 triterpenoids (1-21) were isolated from a methanol extract of the rhizomes and roots of G. scabra. Their structures were elucidated by comparing spectroscopic data with reported values. Among the isolated triterpenoids, scabanol (2) was firstly isolated from natural sources. All isolated compounds were evaluated for their inhibitory activity against indoleamine 2,3-dioxygenase (IDO), which catalyzes the rate limiting reaction for the conversion of tryptophan to kynurenine. Compounds 10 and 11 showed significant inhibitory activities, with IC(50) values of 12.5 and 9.5 µM, respectively. Compound 12 showed a moderate inhibitory effect, with an IC(50) value of 18.7 µM. Compounds 2 and 13 showed weaker inhibitory effects, with IC(50) values of 56.8 and 60.6 µM, respectively. Kynurenine is a potent immune modulator to suppress the functions of a variety of immune cells including T cells and natural killer cells. Given that, our results that a few selected triterpenoids inhibit IDO warrant further studies on their effects on the host immune system as natural immune stimulators.

Preparation, characterization, and photoelectric properties of an electrostatically self-assembled film based on tungstophosphoric acid and a binuclear Ru(II) complex.

An electrostatically self-assembled film based on tungstophosphoric acid (PTA) and a binuclear Ru(II) complex RuL was prepared and characterized by UV-vis absorption spectroscopy and cyclic voltammetry. A linear increase in the UV-vis absorbance with the number of deposited layers indicated that the film deposition was uniform and reproducible. The cyclic voltammogram demonstrated that PTA and the binuclear Ru(II) complex assembled in the film were redox active with surface confined characteristics. The photoelectrochemical properties and mechanism of photocurrent generation have also been studied. A five-layer (PTA/RuL)5 film on the ITO was found to exhibit a large cathodic photocurrent density of 5.32 microA/cm2 while irradiated with polychromatic light (730 nm > lambda > 325 nm) at an applied potential of -0.3 V versus saturated calomel electrode. The photocurrent action spectrum was in agreement with metal-to-ligand charge-transfer (MLCT) band of RuL in the absorption spectrum, which indicated that the photocurrent was generated based on MLCT excitation of the RuL in the film. It is noteworthy that the incident monochromatic photon-to-current conversion efficiency was calculated to be 1.1% at a wavelength of 450 nm.

Preparation, characterization, and photoelectric properties of a covalently self-assembled monolayer of ferrocenyl hemicyanine.

A monolayer of a ferrocenyl hemicyanine was covalently self-assembled on an indium tin oxide (ITO)-coated glass substrate, and was characterized by UV/Vis absorption and X-ray photoelectron spectroscopy, and cyclic voltammetry. The photoelectrochemical properties and mechanism of photocurrent generation have also been studied. This monolayer film was found to exhibit a large anodic photocurrent density of 0.13 microA/cm2 with the highest photoelectric yield of 3.32% under irradiation of white light (730 nm > lambda > 325 nm) at a bias potential of +0.4 V versus saturated calomel electrode.

Modeling methyl isothiocyanate soil flux and emission ratio from a field following a chemigation of metam-sodium.

Metam-sodium had become the most heavily used soil fumigant in recent years as the deadline approached for methyl bromide to phase out in January 2005. After application, metam-sodium decomposes rapidly to methyl isothiocyanate (MITC), a highly toxic compound capable of killing a wide spectrum of soil-borne pests. Inhalation risk of MITC ranked high among airborne agricultural pesticides in California. Information about off-gassing intensity and percentage of emission is essential for exposure risk assessment and mitigation measures, but is limited, especially for new application methods such as drip chemigation. Air concentrations of MITC were monitored around a field treated with metam-sodium through surface drip irrigation system. The field was tarped with plastic films before the chemigation. The air concentrations at receptor locations were simulated for the period of air monitoring with the Industrial Source Complex (ISC3) Dispersion Model, and soil flux density of MITC at various periods after chemigation was estimated through a back-calculation procedure. The estimated soil flux density of MITC showed a diurnal pattern, with the daytime flux stronger than nighttime. However, the average air concentration at nighttime was higher than that at daytime. Soil flux density peaked at 4.30 microg m-2 s-1 in the first 12-h period after chemigation, then declined with time. The MITC emission percentage in the first 60-h was 2.65% of applied mass, of which 57% occurred in the first 24-h after chemigation. The study indicated that the tarped bed drip application method of metam-sodium had a relatively good control of MITC emission from soil.