Triterpenoids,megastigmanes and hydroxycinnamic acid derivatives from Anisomeles indica

Six triterpenoids (1–6), four megastigmanes (7–10) and five hydroxycinnamic acid derivatives (11–15) were isolated from the aerial part of Anisomeles indica (Lamiaceae). Of these components, compound 1 was identified to be a new triterpenoid with the structure of 2α,3α,19α-trihydroxyurs-12,20(30)-dien-28-oic acid based on extensive analysis of MS, 1D and 2D NMR spectroscopic data, while compounds 2–13 were obtained for the first time from Anisomeles species.     

Characterization of hydroxycinnamic acid derivatives binding to bovine serum albumin

Hydroxycinnamic acid derivatives (HCAs) are a group of naturally occurring polyphenolic compounds which possess various pharmacological activities. In this work, the interactions of bovine serum albumin (BSA) with six HCA derivatives, including chlorogenic acid (CHA), caffeic acid (CFA), m-coumaric acid (m-CA), p-coumaric acid (p-CA), ferulic acid (FA) and sinapic acid (SA) have been investigated by NMR spectroscopic techniques in combination with fluorescence and molecular modeling methods. Competitive STD NMR experiments using warfarin sodium and L-tryptophan as site-selective probes indicated that HCAs bind to site I in the subdomain IIA of BSA. From the analysis of the STD NMR-derived binding epitopes and molecular docking models, it was deduced that CHA, CFA, m-CA and p-CA show similar binding modes and orientation, in which the phenyl ring is in close contact with protein surface, whereas carboxyl group points out of the protein. However, FA and SA showed slightly different binding modes, due to the steric hindrance of methoxy-substituents on the phenyl ring. Relaxation experiments provided detailed information about the relationship between the affinity and structure of HCAs. The binding affinity was the strongest for CHA and ranked in the order CHA > CFA > m-CA ≥ p-CA > FA > SA, which agreed well with the results from fluorescence experiments. Based on our experimental results, we also conclude that HCAs bind to BSA mainly by hydrophobic interaction and hydrogen bonding. This study therefore provides valuable information for elucidating the mechanisms of BSA-HCAs interaction.     

Profiling of hydroxycinnamic acid amides in Arabidopsis thaliana pollen by tandem mass spectrometry

Phenylpropanoid polyamine conjugates are widespread in plant species. Their presence has been established in seeds, flower buds, and pollen grains. A biosynthetic pathway proposed for hydroxycinnamoyl spermidine conjugates has been suggested for the model plant Arabidopsis thaliana with a central acyl transfer reaction performed by a BAHD-like hydroxycinnamoyl transferase. A detailed liquid chromatography (LC)–electrospray ionization–mass spectrometry- and tandem-mass-spectrometry (MS/MS)-based survey of wild-type and spermidine hydroxycinnamoyl transferase (SHT) mutants identified more than 30 different bis- and tris-substituted spermidine conjugates, five of which were glycosylated, in the methanol-soluble fraction of the pollen exine. On the basis of characterized fragmentation patterns, a high-throughput LC–MS/MS method for highly sensitive HCAA relative quantification (targeted profiling) was developed. Only minor qualitative and quantitative differences in the pattern of bis-acyl spermidine conjugates in the SHT mutant compared to wild-type plants provide strong evidence for the presence of multiple BAHD-like acyl transferases and suggest a much more complex array of enzymatic steps in the biosynthesis of these conjugates than previously anticipated.     

Structure of hydroxycinnamic acid derivatives established by high-performance liquid chromatography with photodiode-array detection

Summary The present paper describes the development of a method for the differentiation of hydroxycinnamic acid derivatives by HPLC with photodiode-array detection. Furthermore spectral data of the compounds under investigation are given. Whereas p-coumaric acid derivatives are distinguishable from caffeic and ferulic acid derivatives by the positions of their spectrum maxima and their convexity interval value, it is not possible to distinguish between caffeic and ferulic acid derivatives because of overlapping spectrum maxima and convexity interval values.     

Structure of hydroxycinnamic acid derivatives established by high-perfomance liquid chromatography with photodiode-array detection

Summary The present paper describes the development of a method for the differentiation of hydroxycinnamic acid derivatives by HPLC with photodiode-array detection. Furthermore spectral data of the compounds under investigation are given. Whereas p-coumaric acid derivatives are distinguishable from caffeic and ferulic acid derivatives by the positions of their spectrum maxima and their convexity interval value, it is not possible to distinguish between caffeic and ferulic acid derivatives because of overlapping spectrum maxima and convexity interval values.     

Antioxidative properties of hydroxycinnamic acid derivatives and a phenylpropanoid glycoside. A pulse radiolysis study

Spectral and redox properties of the phenoxyl radicals from hydroxycinnamic acid derivatives and one selected component of phenylpropanoid glycosides, verbascoside, were studied using pulse radiolysis techniques. On the basis of the pH dependence of phenoxyl radical absorptions, the pK_a values for deprotonation of sinapic acid radical and ferulic acid radical are 4.9 and 5.2. The rate constants of one electron oxidation of those antioxidants by azide radical and bromide radical ion were determined at pH 7. The redox potentials of those antioxidants were determined as 0.59–0.71 V vs NHE at pH 7 with reference standard 4-methoxyphenol and resorcinol.     

Antioxidant bibenzyl derivatives from Notholaena nivea Desv

Four new bibenzyl derivatives were isolated, together with other known bibenzyls, by bioassay-guided fractionation of a CHCl?-MeOH extract of Notholaena nivea Desv. (Pteridaceae) aerial parts. The structures were elucidated by NMR, ESIMS and other spectral analyses. Their antioxidative effects towards superoxide, lipidic peroxidation and the 2,2'-azino-bis-3-ethilbenzothiazoline-6-sulfonic acid (ABTS) radical were assayed. Results showed that the compound 3,12-dihydroxy-5-methoxybibenzyl (6) is the most active compound in the ABTS free-radical scavenging test, while in the coupled oxidation of β-carotene and linoleic acid assay the compound 5,12-dihydroxy-3-methoxydibenzyl-6-carboxylic acid (1) exerted the highest activity after 1h. A superoxide anion enzymatic test was also carried out and the results were confirmed by an inhibition of xanthine oxidase activity assay. The putative protective role played by compounds 1 and 6 on the injurious effects of reactive oxygen metabolites on the intestinal epithelium, using a Caco-2 human cell line, was investigated. H?O?-induced alterations were prevented by preincubating the cells with compounds 1 and 6.     

Antioxidant hispidin derivatives from medicinal mushroom Inonotus hispidus

Two natural antioxidants, named inonotusin A (1) and B (2), were isolated from the methanolic extract of the fruit bodies of Inonotus hispidus, together with (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one (3), hispidin (4) and 3,4-dihydroxybenzaldehyde (5). Their structures were identified by means of extensive NMR and MS data analysis. Compounds 1, 2 and 4 exhibited significant scavenging activity against the 2,20-azinobis(3-ethylbenzhiazoline-6-sulfonate) (ABTS) radical cation. Compound 1 also showed moderate cytotoxicity against a human breast carcinoma cell line (MCF-7) with IC(50) values of 19.6 μM.     

Antioxidant activity of honey supplemented with bee products

The aim of this work was to evaluate the influence of supplementation of multiflower honey with bee products on the phenolic compound content and on antioxidant activity. Average total phenolic and flavonoids contents in the multiflower honeys were 36.06 ± 10.18 mg GAE/100 g and 4.48 ± 1.69 mg QE/100 g, respectively. The addition of royal jelly did not affect significantly the phenolic compound content and antioxidant activity. Supplementation of honey with other bee products, i.e. beebread, propolis, pollen, resulted in significant increase in the total phenolic and flavonoids contents, and in antiradical activity and reducing power, with the largest effect found for addition of beebread. Significant linear correlations between the total phenolic and flavonoids contents and antiradical activity and reducing power were found.     

Authentication of black cohosh (Actaea racemosa) dietary supplements based on chemometric evaluation of hydroxycinnamic acid esters and hydroxycinnamic acid amides

Analytical and Bioanalytical Chemistry - Ester and amide derivatives of hydroxycinnamic acids are found in black cohosh (Actaea racemosa) and other Actaea plants. These two compound groups were...     

Liquid chromatographic-mass spectrometric analysis of anthocyanin composition of dark blue bee pollen from Echium plantagineum

Dark blue bee pollen samples from pollinic type Echium plantegineum were analysed in order to identify and quantify their anthocyanin pigments. Five samples were collected from different apicultural Spanish regions and the anthocyanin composition was determined by HPLC with diode array and MS detection. Eight different pigments were identified, the principal anthocyanin being petunidin-3-O-rutinoside. The other pigments found were delphinidin, cyanidin and petunidin-3-O-glucoside; delphinidin, cyanidin, peonidin and malvidin-3-O-rutinoside and cyanidin-3-(6"-malonylglucoside). The anthocyanin content ranged from 45 to 80 mg/100 g of blue pollen, which could represent a significant source of phytochemicals. Minor variations in the anthocyanin profiles were found, which could be explained by the geographical differences between collection regions.     

Antibacterial thymol derivatives isolated from Centipeda minima

Two new monoterpenoids, 8,10-dihydroxy-9(2)-methylbutyryloxythymol (1) and 10-hydroxy-8,9-dioxyisopropylidene-thymol (2), together with five known thymol derivatives: 8,9,10-trihydroxythymol (3), thymol-beta-glucopyranoside (4), 9-hydroxythymol (5), 8,10-dihydroxy-9-isobutyryloxythymol (6), and 8-hydroxy-9,10-diisobutyryloxythymol (7), were isolated from Centipeda minima. Their structures were identified by means of spectroscopic analyses. Interestingly, compound 2 is not an extraction artifact according to a close HPLC examination of material after extraction by analytical MeOH at ambient temperature. The antibacterial activities of compounds 1-7 were evaluated against eight microbial strains by the agar dilution method.     

On the peroxyl scavenging activity of hydroxycinnamic acid derivatives: mechanisms, kinetics, and importance of the acid-base equilibrium

The peroxyl radical scavenging activity of four hydroxycinnamic acid derivatives (HCAD) has been studied in non-polar and aqueous solutions, using the density functional theory. The studied HCAD are: ferulic acid (4-hydroxy-3-methoxycinnamic acid), p-coumaric acid (trans-4-hydroxycinnamic acid), caffeic acid (3,4-dihydroxycinnamic acid), and dihydrocaffeic acid (3-(3,4-dihydroxyphenyl)-2-propionic acid). It was found that the polarity of the environment plays an important role in the relative efficiency of these compounds as peroxyl scavengers. It was also found that in aqueous solution the pH is a key factor for the overall reactivity of HCAD towards peroxyl radicals, for their relative antioxidant capacity, and for the relative importance of the different mechanisms of reaction. The H transfer from the phenolic OH has been identified as the main mechanism of reaction in non-polar media and in aqueous solution at acid pHs. On the other hand, the single electron transfer mechanism from the phenoxide anion is proposed to be the one contributing the most to the overall peroxyl scavenging activity of HCAD in aqueous solution at physiological pH (7.4). This process is also predicted to be a key factor in the reactivity of these compounds towards a large variety of free radicals.     

Phosphorus acid derivatives from 3,6-di-tert-butylpyrocatechol

Conclusions The reaction of 3,6-di-tert-butylpyrocatechol with the acid chlorides of various phosphorus acids was studied: reaction with PCl₃ gives the spirophosphorane, while reaction with diphenylchlorophosphine gives the diphenyl-1,2-phenylenedioxyphosphorane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2385–2388, October, 1978.     

Production and purification of CGTase of alkalophylicBacillus isolated from Brazilian soil

Alkalophylic bacilli that produce cyclodextringlycosyltransferase (CGTase) were isolated from Brazilian soil, with a scheme of two plating steps. In the first step, the bacterial isolate forms a halo in the cultivation medium that contains γ-cyclodextrin (CD) complexing dyes. The CGTase of an isolate was purified 157-fold by biospecific affinity chromatography, with β-CD showing a mol wt of 77,580 Daltons. It produces a γ- to β-CD ratio of 0.156 and a small amount of α-CD, using maltodextrin 10% as substrate, at 50°C, pH 8.0 and 22 h reaction time, reaching 21.4% conversion of the substrate to cyclodextrins. In the second screening step, the isolates chosen give larger halos with β-CD complexing dyes, and smaller halos with β-CD complexing dyes, leading to a 30% improvement in γ-CD selectivity, although at lower total yield for cyclodextrins (11.5%).     

Antioxidant activity of uracil derivatives

The antiradical properties of a number of uracil derivatives are studied in initiated 1,4-dioxane oxidation as a model reaction. The antioxidant activity of the uracil derivatives as inhibitors is estimated. The antiradical activity of the compounds is quantitatively characterized in terms of the effective rate constant of inhibition, fk _In.     

Antioxidant coumarin and pyrone derivatives from the insect-associated fungus Aspergillus Versicolor

Abstract

Two new compounds, versicolones A and B (1 and 2), and three known pyrone derivatives (3?5) were isolated from the insect-associated fungus Aspergillus versicolor. Their structures were elucidated through a combination of HRESIMS and NMR spectroscopic analysis. Versicolone A (1) was revealed as a coumarin derivative with the rare 5-alkyl side chain substitution. Compound 5 exhibited significant antioxidant activity with EC₅₀ value of 8.0?μM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was more than 2-fold potency of the positive control trolox.     

Volatile compounds composition and antioxidant activity of bee pollen collected in Lithuania

Characterization of volatile compounds composition and evaluation of antioxidant properties of bee pollen collected in Lithuania is presented in the paper, which is the first study on pollen of Lithuanian origin to our knowledge. Three polyfloral pollen samples collected by honey bees were analyzed. Characterization of volatile compounds was performed using solid phase microextraction (SPME) and GC-MS. Styrene was predominant in all samples contributing 19.6–27.0 mass %. Sample A distinguished by a high amount of limonene, 9.0 mass %, sample B differed from the rest by a high content of hexanal, 9.3 mass %, and nonanal, 12.3 mass %, while sample C showed the highest content of 1-tridecene, 43.3 mass %. Screening of antioxidant properties was carried out by spectrophotometric methods and liquid chromatography coupled with a post-column 1,1-diphenyl-2-picrylhydrazyl (DPPH) reaction detector and electrochemical detector. Total phenolic and flavonoid contents together with radical scavenging activity in the free radical (DPPH) model system were evaluated in the tested samples. Total phenolic content varied from 24.4 mg g^?1 to 38.9 mg g^?1, total flavonoid content was in the range of 7.3–10.0 mg g^?1 and radical scavenging activity was found between 30.7 mg g^?1 and 34.9 mg g^?1, all data are expressed in rutin equivalents. To process the collected data statistically and classify the bee pollen samples to clusters according to their volatile composition and antioxidant activity, principal component analysis, hierarchical cluster analysis and non-linear discriminant analysis were applied.     

Cellulose derivatives from cellulosic material isolated from Agave lechuguilla and fourcroydes

Fibers isolated from Agave lechuguilla(lechuguilla) and fourcroydes (henequen) contain about 80%cellulose, 5% hemicellulose and 15% lignin. They are a renewable resource,interesting as feedstock for new products obtained by chemicalfunctionalization. In the present paper the reactivity of such fibrousmaterialsunder typical conditions for modification of cellulose was studied. Treatmentwith n-octanol/aqueous NaOH of the fibers leads to an activated expandedgel-like material with enhanced accessibility. Carboxymethylation, sulfation,acetylation and tritylation reactions as well as subsequent carboxymethylationof the trityl derivative and selective oxidation of the primary hydroxylfunction of carboxymethylated products with TEMPO/NaBr/NaClO were successfullycarried out under conditions typical for cellulose reactions. The products werecharacterized by means of ¹³C-NMR and ¹H-NMR spectroscopyandHPLC after complete depolymerization, by GPC, and by the determination ofsolubility.