Chemical composition, antioxidant and alpha-Glucosidase-Inhibiting activities of the aqueous and hydroethanolic extracts of Vaccinium myrtillus Leaves

Vaccinium myrtillus (bilberry) leaf is traditionally used in southeastern Europe for the treatment of diabetes. In the present study, the ability of bilberry leaf extracts to inhibit carbohydrate-hydrolyzing enzymes and restore glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress was investigated. A comprehensive analysis of the antioxidant activity of two bilberry leaf extracts was performed. The aqueous extract showed excellent total antioxidant and chelating activity. Its antioxidant activity in the beta-carotene-linoleic acid assay was very good, reaching the activity of the antioxidant standard BHA (93.4 +/- 2.3% vs. 95.1 +/- 2.4%, respectively). The hydroethanolic extract (ethanol/H2O, 8:2, v/v), on the other hand, was a better radical scavenger and Fe2+ reducing agent. Furthermore, the aqueous extract was able to efficiently increase glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress and restore it to the levels observed in non-hyperglycaemic cells. The hydroethanolic extract strongly inhibited alpha-glucosidase, with the IC50 statistically equal to the antidiabetic drug acarbose (0.29 +/- 0.02 mg/mL vs. 0.50 +/- 0.01 mg/mL, respectively). Phytochemical analysis revealed the presence of quercetin and kaemferol derivatives, as well as chlorogenic and p-coumaric acid. The study results indicate that V. myrtillus leaf may have promising properties as a supporting therapy for diabetes.University of Zagrebinfo:eu-repo/semantics/publishedVersio

Natural Compounds as Beneficial Antioxidant Agents in Neurodegenerative Disorders: A Focus on Alzheimer’s Disease

The positive role of nutrition in chronic neurodegenerative diseases (NDs) suggests that dietary interventions represent helpful tools for preventing NDs. In particular, diets enriched with natural compounds have become an increasingly attractive, non-invasive, and inexpensive option to support a healthy brain and to potentially treat NDs. Bioactive compounds found in vegetables or microalgae possess special properties able to counteract oxidative stress, which is involved as a triggering factor in neurodegeneration. Here, we briefly review the relevant experimental data on curcuminoids, silymarin, chlorogenic acid, and compounds derived from the microalga Aphanizomenon flos aquae (AFA) which have been demonstrated to possess encouraging beneficial eects on neurodegeneration, in particular on Alzheimer’s disease models

Screening the effect of four ultrasound-assisted extraction parameters on hesperidin and phenolic acid content of aqueous citrus pomace extracts

Polyphenols of citrus by-products, due to their antioxidant and antimicrobial activities, could be valorized by pharmaceutical and food industries, adding a value to the citrus processing companies. A number of studies have investigated the effect of ultrasound-assisted extraction (UAE) conditions on the recovery of phenolics derived from citrus waste using both organic solvents or mixed aqueous solvent systems. To maximize efficiency, UAE conditions should be tailored to the physical parameters of the solvent(s) employed. The aim of this study was to investigate the effect of four UAE parameters: particle size (1.40–2.80 mm), extraction time (10–60 min), extraction temperature (23–50 °C) and ultrasonic power (150–250 W) on the simultaneous recovery of p-coumaric acid, caffeic acid, chlorogenic acid, and hesperidin from citrus waste using pure water as a solvent. High-performance liquid chromatography (HPLC) was employed for the identification and quantification of the cited compounds. Particle size was determined to be an important parameter affecting compound recovery, with the exception of chlorogenic acid. A particle size of 1.40 mm resulted in the highest recovery of p-coumaric and caffeic acids (0.25 and 0.58 mg/g, respectively), while higher hesperidin yields were achieved from the particle sizes of 2.00 and 1.40 mm (6.44 and 6.27 mg/g, respectively). Extraction temperature significantly affected only the recovery of the flavanone glycoside (P<0.05). As the extraction temperature increased from 30 to 50 °C the recovery of hesperidin increased from 6.59 to 7.84 mg/g, respectively. Neither extraction time nor ultrasonic power significantly affected the recovery of any individual phenolic compound

The polyphenolic and hydroxycinnamate contents of whole coffee fruits from China, India and Mexico

Air dried whole coffee fruits, beans and husks from China, India and Mexico were analysed for their chlorogenic acids (CGA), caffeine, and polyphenolic content. Analysis was by HPLC and Orbitrap exact mass spectrometry. Total phenol, total flavonol and antioxidant capacity were measured. The hydroxycinnamate profile consisted of caffeoylquinic acids, feruloyquinic acids, dicaffeoylquinic acids and caffeoyl-feruloylquinic acids. A range of flavan-3-ols as well as flavonol conjugates were detected. The CGA content was similar for both Mexico and India coffee fruits but was much lower in China samples. Highest levels of flavan-3-ols were found in the Indian samples whereas Mexico samples contained the highest flavonols. Amounts of CGAs in the beans were similar to those in the whole fruits, but flavan-3-ols and flavonols were not detected. The husks contained the same range of polyphenols as in the whole fruits. Highest levels of caffeine were found in the Robusta samples

UHPLC-PDA-ESI-TOF/MS metabolic profiling and antioxidant capacity of arabica and robusta coffee silverskin: antioxidants vs phytotoxins

A deeper knowledge of the chemical composition of coffee silverskin (CS) is needed due to the growing interest in its use as a food additive or an ingredient of dietary supplements. Accordingly, the aim of this paper was to investigate the metabolic profile of aqueous extracts of two varieties of CS, Coffee arabica (CS-A), Coffee canephora var. robusta (CS-R) and of a blend of the two (CS-b) and to compare it to the profile of Coffee arabica green coffee (GC). Chlorogenic acids, caffeine, furokauranes, and atractyligenins, phytotoxins not previously detected in CS, were either identified or tentatively assigned. An unknown compound, presumably a carboxyatractyligenin glycoside was detected only in GC. Caffeine and chlorogenic acids were quantified while the content of furokauranes and atractyligens was estimated. GC and CS were also characterized in terms of total polyphenols and antioxidant capacity. Differences in the metabolites distribution, polyphenols and antioxidant capacity in CG and CS were detailed

Response of organically and conventionally produced potatoes to a controlled attack of a pathogen

Organic agricultural products have increasing share of the food market in Europe. The questions related to benefits of organic versus conventionally produced agricultural crops are of increasing meaning. In our paper we have focused on assessment of the reaction of the immunity system of potato tubers from both agricultural systems on an external controlled attack of Phytophthora infestans, a pathogenic microorganism. The reaction of organic and conventional potato tubers was expressed via determination of chlorogenic acid. The content of chlorogenic acid in organic potato tubers increased 1.3 times after an attack, compared to potato tubers without a microbial attack. In conventional potato tubers, the increase was 4 times higher in the same way of comparison. The observed increase in conventional tubers is an evident exaggerated protection reaction to the attack of a natural potato pathogen. It is evident that there is a difference between the reaction of the immunity system of organic versus conventional potato tubers � phytoallergy

Effect of Chlorogenic Acid and Neochlorogenic Acid on Human Colon Cancer Cells

Prune consumption has been associated with a decreased risk of colon cancer, yet there has been confusion as to which chemical component(s) of the prune are responsible for its anticarcinogenic properties. Previous studies have evaluated chlorogenic acid as a chemotherapeutic agent, however only a limited amount of studies have investigated neochlorogenic acid, the predominant phenolic compound found in the prune. The purpose of this study was to determine the effects that chlorogenic acid and neochlorogenic acid have as anticarcinogenics on the human adenocarcinoma, Caco-2 cell line. The anti-colon cancer effects or chlorogenic acid and neochlorogenic acid were analyzed by experiments that measured cell proliferation and morphology in culture of Caco-2 cells. Treatment of cells with chlorogenic acid and neochlorogenic acid significantly reduced cell proliferation at concentrations of 150-500μmol at 24, 48, and 72 hours by 63.7-96.0% and 69.7-94.2%, respectively (p\u3c0.05). At the majority of sample times and concentrations, chlorogenic acid and neochlorogenic acid did not significantly differ in percent reduction of viable cells (p\u3c0.05). The cell morphology of treated cells changed, as the surface of cells became more rough, uneven, and irregularly-shaped as the concentration of the treatment increased, compared to the untreated Caco-2 cell. These findings of significant cell proliferation inhibition suggest that both chlorogenic acid and neochlorogenic acid could be colon cancer suppressive components of the prune

Biotransformation of caffeoyl quinic acids from green coffee extracts by Lactobacillus johnsonii NCC 533

Acknowledgements The authors are grateful to Nicole Page-Zoerkler and Olivier Mauroux for their technical assistant. We thank David Pridmore and Kimo Makkinen for critical reading of this manuscript.Peer reviewedPublisher PD

Acidity and Antioxidant Activity of Cold Brew Coffee.

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew counterparts. It was also noted that both the concentration of total titratable acids and antioxidant activity correlated poorly with total CQA concentration in hot brew coffee. This work suggests that the hot brew method tends to extract more non-deprotonated acids than the cold brew method. These acids may be responsible for the higher antioxidant activities observed in the hot brew coffee samples

Espresso coffees, caffeine and chlorogenic acid intake: potential health implications

HPLC analysis of 20 commercial espresso coffees revealed 6-fold differences in caffeine levels, a 17-fold range of caffeoylquinic acid contents, and 4-fold differences in the caffeoylquinic acid:caffeine ratio. These variations reflect differences in batch-to-batch bean composition, possible blending of arabica with robusta beans, as well as roasting and grinding procedures, but the predominant factor is likely to be the amount of beans used in the coffee-making/barista processes. The most caffeine in a single espresso was 322 mg and a further three contained >200 mg, exceeding the 200 mg day−1 upper limit recommended during pregnancy by the UK Food Standards Agency. This snap-shot of high-street expresso coffees suggests the published assumption that a cup of strong coffee contains 50 mg caffeine may be misleading. Consumers at risk of toxicity, including pregnant women, children and those with liver disease, may unknowingly ingest excessive caffeine from a single cup of espresso coffee. As many coffee houses prepare larger volume coffees, such as Latte and Cappuccino, by dilution of a single or double shot of expresso, further study on these products is warranted. New data are needed to provide informative labelling, with attention to bean variety, preparation, and barista methods