Phytochemical and biological study of phenolic fraction from Geoffroea decorticans bark

The stem bark of Geoffroea decorticans(Gill.ex Hook. etArn.) Burk. was used medicinally to cure several skin affections; however, phytochemical and biological antecedents were not found. Analyses of purified methanolic extract from G. decorticansbark (PFGB), realized by silylation derivatization for GC/MS, C18-CC and HPLC followed by two-dimensional TLC and UV-Vis spectroscopy, allowed to characterize nine phenolic compounds, among these, two methoxy flavonoids. Antibacterial assays of PFGB showed the highest activity (MICs= 125 μg/mL) against Staphylococcus aureus(25923) and Enterococcus faecalis(29212) ATCC strains. Moreover, PFGB showed the highest intracellular antioxidant activity at low concentration (5 μg/mL), evaluated by using the fluorescent DA-H2DCF probe on lymphocyte culture; cytotoxic effects on lymphocytes activated or not by LPS were not observed, through Trypan Blue Exclusion and MTT colorimetric assays.The results obtained from the ethnomedicinal approach of this work contribute to the scientific validation of the vulnerary medicinal use of G. decorticans.

Determination of the phenolic composition of sherry and table white wines by liquid chromatography and their relation with antioxidant activity

Potential for food–drug interactions by dietary phenolic acids on human organic anion transporters 1 (SLC22A6), 3 (SLC22A8), and 4 (SLC22A11)

Effect of roasting and in vitro digestion on phenolic profiles and antioxidant activity of water-soluble extracts from sesame

Postharvest UV-B and UV-C treatments combined with fermentation enhance the quality characteristics of Capparis spinosa L. fruit, improving total phenols, flavonoids, anthocyanins, phenolic acids, and antioxidant activity.

Effect of gallic and protocatechuic acids on the metabolism of ethyl carbamate in Chinese yellow rice wine brewing

The present investigation was undertaken to estimate contents of bioactive phenolic compounds in A. pindrow aerial parts using TLC densitometry. Maltol, p-coumaric acid, p-hydroxy benzoic acid, protocatechuic acid and gallic acid were resolved in TLC of methanol extract of plant using solvent systems – chloroform:methanol (9.7:0.3; scanned at 276 nm), toluene:diethyl ether (1:1; scanned at 320 nm), chloroform:methanol:glacial acetic acid (19:1:1; scanned at 266 nm), chloroform:methanol:formic acid (9:1:1; scanned at 295 nm) and chloroform:methanol:acetonitrile: formic acid (12:3:3:2; scanned at 292), respectively. The developed methods for estimation of phenolic compounds in plant were validated as per ICH guidelines. The contents of maltol, p-coumaric acid, p-hydroxy benzoic acid, protocatechuic acid and gallic acid in plant were found to be 0.10280±0.00002, 0.00860±0.00000, 0.00780±0.00001, 0.10030±0.00003 and 0.06440±0.00002% w/w, respectively. On the basis of validation parameters, the developed TLC densitometric methods for estimation of phenolic compounds in the plant were found to precise, accurate and specific.

Antioxidant and DNA damage protection potentials of selected phenolic acids

The phenolic acid profile of honey depends greatly on its botanical and geographical origin. In this study, we carried out a quantitative analysis of phenolic acids in the ethyl acetate extract of 12 honeys collected from various regions in Greece. Our findings indicate that protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid and p-coumaric acid are the major phenolic acids of the honeys examined. Conifer tree honey (from pine and fir) contained significantly higher concentrations of protocatechuic and caffeic acid (mean: 6640 and 397 µg/kg honey respectively) than thyme and citrus honey (mean of protocatechuic and caffeic acid: 437.6 and 116 µg/kg honey respectively). p-Hydroxybenzoic acid was the dominant compound in thyme honeys (mean: 1252.5 µg/kg honey). We further examined the antioxidant potential (ORAC assay) of the extracts, their ability to influence viability of prostate cancer (PC-3) and breast cancer (MCF-7) cells as well as their lowering effect on TNF- α-induced adhesion molecule expression in endothelial cells (HAEC). ORAC values of Greek honeys ranged from 415 to 2129 µmol Trolox equivalent/kg honey and correlated significantly with their content in protocatechuic acid (p<0.001), p-hydroxybenzoic acid (p<0.01), vanillic acid (p<0.05), caffeic acid (p<0.01), p-coumaric acid (p<0.001) and their total phenolic content (p<0.001). Honey extracts reduced significantly the viability of PC-3 and MCF-7 cells as well as the expression of adhesion molecules in HAEC. Importantly, vanillic acid content correlated significantly with anticancer activity in PC-3 and MCF-7 cells (p<0.01, p<0.05 respectively). Protocatechuic acid, vanillic acid and total phenolic content correlated significantly with the inhibition of VCAM-1 expression (p<0.05, p<0.05 and p<0.01 respectively). In conclusion, Greek honeys are rich in phenolic acids, in particular protocatechuic and p-hydroxybenzoic acid and exhibit significant antioxidant, anticancer and antiatherogenic activities which may be attributed, at least in part, to their phenolic acid content.

Phenolic acids are found in abundance throughout the plant kingdom. Consumption of wine or other rich sources of phenolic acids, such as the "Mediterranean diet," has been associated with a lower risk of cardiovascular disease. The underlying mechanism(s), however, has remained unclear. Here, we show that many phenolic acids, including those from the hydroxybenzoic and hydroxycinnamic acid classes, can bind and activate GPR109A (HM74a/PUMA-G), the receptor for the antidyslipidemic agent nicotinic acid. In keeping with this activity, treatment with a number of phenolic acids, including cinnamic acid, reduces lipolysis in cultured human adipocytes and in fat pats isolated from wild-type mice but not from mice deficient of GPR109A. Oral administration of cinnamic acid significantly reduces plasma levels of FFA in the wild type but not in mice deficient of GPR109A. Activation of GPR109A by phenolic acids may thus contribute to a cardiovascular benefit of these plant-derived products.

In the present study, the efficacy of generally recognised as safe (GRAS) antimicrobial plant metabolites in regulating the growth of Staphylococcus aureus and S. epidermidis was investigated. Thymol, carvacrol and eugenol showed the strongest antibacterial action against these microorganisms, at a subinhibitory concentration (SIC) of ≤ 50 μg ml−1. Genistein, hydroquinone and resveratrol showed antimicrobial effects but with a wide concentration range (SIC = 50–1,000 μg ml−1), while catechin, gallic acid, protocatechuic acid, p-hydroxybenzoic acid and cranberry extract were the most biologically compatible molecules (SIC ≥ 1000 μg ml−1). Genistein, protocatechuic acid, cranberry extract, p-hydroxybenzoic acid and resveratrol also showed anti-biofilm activity against S. aureus, but not against S. epidermidis in which, surprisingly, these metabolites stimulated biofilm formation (between 35% and 1,200%). Binary combinations of cranberry extract and resveratrol with genistein, protocatechuic or p-hydroxibenzoic acid enhanced the stimulatory effect on S. epidermidis biofilm formation and maintained or even increased S. aureus anti-biofilm activity.

Evaluation of antimicrobial and antioxidant activities of natural phenolic compounds against foodborne pathogens and spoilage bacteria

The authors extracted phenolic compounds from each horizon of a Spodosol profile using three extractants: 0.1 M sodium pyrophosphate at pH 7.0 and 10.2, and 0.5 N sodium hydroxide at pH 13.4. Of 28 standard compounds evaluated seven phenolic compounds were identified: three carboxylic acids - protocatechuic, p-hydroxybenzoic, and vanillic acids; two aldehydes - vanillin and p-hydroxybenzaldehyde; and two cinnamic acids - trans p-coumaric and ferulic acids. The three most abundant compounds evaluated were protocatechuic acid, p-hydroxybenzoic acid, and vanillic acid. The amounts of each phenolic compound extracted increased with increasing pH of the extractant except for protocatechuic acid. Protocatechuic acid was extracted in the highest amounts by sodium pyrophosphate pH 10. The pyrophosphate (pH .10) extracts revealed that protocatechuic acid tended to accumulate in the B horizons, suggesting that it may play a role in the translocation of metal ions during podzolization. The two cinnamic acids, trans p-coumaric and ferulic, were extracted primarily by NaOH. The identification of these cinnamic derivatives in an NaOH extraction of roots separated from the B horizon suggested that their presence may be due to degradation of plant residues by NaOH. Pyrophosphate (pH 7) extracted only small amounts of phenolic compounds. The specificity ofmore » pyrophosphate (pH 10) in removing organic complexes of a possible pedogenic nature suggest that it was the better extractant. Sodium pyrophosphate (pH 10) is recommended for use in future pedological studies of phenolic substances.« less

Phenolic acids play an important role in the formation of soil profiles, however their cooperative sorption by mineral phases under environmentally relevant concentrations is poorly studied. In the present work the sorption of an equimolar mixture of phenolic acids by kaolinite modified with amorphous aluminum hydroxide has been studied under both batch and continuous-flow conditions. It has been found that the sorption of gallic and protocatechuic acids containing OH groups in the ortho position exceeds the sorption of p-hydroxybenzoic and methoxylated acids (vanillic, syringic, and ferulic) by an order of magnitude. The study of sorption under dynamic (continuous-flow) conditions has shown the competition of acids for binding sites, while the active centers of kaolinite-Al(OH)x are being occupied. The sorbed gallic acid displaces the other acids, which pass into solution in the following order: p-hydroxybenzoic acid > vanillic acid > syringic acid ≫ ferulic acid > protocatechuic acid. The revealed regularities indicate potentially important role of ortho-substituted hydroxybenzoic acids in the formation of soil organic matter, while p-hydroxybenzoic, vanillic, and syringic acids can be more important for the composition of soil solutions and natural waters.

The solid residue (cake) of pressed Brazil nut oil has high energy value and contains high levels of nutrients and bioactive compounds, such as polyphenols. However, little is known about these components in this by-product. Extraction is the first step in investigating the phenolic compounds in Brazil nut cake because extraction conditions might impact the yields of phenolic compounds and antioxidant capacity. The aim of this study was to select the best phenolic compound extraction conditions for Brazil nut cake by using factorial experimental design and to characterize the phenolic compounds in the extract. The optimal extraction of antioxidant phenolic compounds from Brazil nut cake was achieved under the following conditions: ethanol-water (40:60; v/v); 2.5 min homogenization; and 1 h extraction at 60 °C. The phenolic compound profile of the Brazil nut cake extract using the optimized extraction was determined by high-performance liquid chromatography with photodiode array detection. Six phenolic acids (gallic acid, protocatechuic acid, 2,4-dihydroxybenzoic acid, p-hydroxybenzoic acid, p-coumaric acid and sinapic acid) and one flavonoid ((+)-catechin) were identified, and the contents of the phenolic compounds varied from 70.0 to 421 mg kg(-1) . Knowledge of the potential bioactivity of Brazil nut cake identified in the present study might promote its use in the food industry. © 2015 Society of Chemical Industry.