Folin-Ciocalteu Spectrophotometric Method Research Articles

Chemical constituents and larvicidal activity of the microencapsulated essential oil of Citrus aurantium L. against Aedes aegypti

This study aimed to evaluate the chemical profile and larvicidal activity of the microencapsulated essential oil (EO) of Citrus aurantium L. against Aedes aegypti. The barks of C. aurantium were collected in São Luís-MA. The EO was extracted by hydrodistillation at 100°C for 3h, with chemical characterization through Gas Chromatography coupled with mass spectrometry (GC-MS). Encapsulation of the EO was performed by ionic gelling. To quantify the total phenolic content of the EO, the Folin-Ciocalteu spectrophotometric method was applied. Then, the lethality of the EO against Aedes aegypti was evaluated, and the LC50 for the action of the EO was calculated using the Probit method. The major constituents found in the EO of C. aurantium were: (-)-Terpinen-4-ol (32, 56%) and Caryophyllene oxide (23.52%). The larvicidal activity of the EO showed a LC50 of 3.589 mg L-1. The results indicate that the evaluated EO is composed of substances that provide a good larvicidal effect, revealing its efficiency in combating and controlling Aedes aegypti.

A Study of the UV Spectral Features in Wine and Their Correlation with Phenolic Constituents

Background: This study investigated the ultraviolet (UV) absorption spectra of various types and ages of grape wines and the correlation these spectra presented with their phenolic constituents. Firstly, the differences in UV spectra were characterized for different wine samples, depending on their type and age. Methods: The following methods were used in this study: ultraviolet visible spectrophotometry, Folin–Ciocalteu spectrophotometric method, high-performance liquid chromatography. Results: Then, it was demonstrated that for identically aged wines, the 280 nm absorbance is proportional to the concentration of phenolic compounds, as determined by the Folin–Ciocalteu method. Next, an investigation was conducted into the absorption coefficients of different phenolic classes commonly found in grapes and wine. Finally, the range in variation of phenolic compounds in various types of grape wines was established. Conclusions: This work provides a methodological approach to rapidly determine the concentration of phenolic compounds in wines using UV spectroscopy, provided that their age is known. As UV spectrophotometers are available in nearly all laboratories, this may provide a cheaper and faster alternative to current methods, including high-performance liquid chromatography (HPLC).

Ecological control of mycotic pathogens in tomato crops - alternatives to synthetic pesticides

The pathogens Alternaria solani and Fusarium oxysporum f. sp. lycopersici are of significant interest from a pathogenic perspective in the context of tomato cultivation. This study focuses on evaluating the fungicidal and fungistatic effects of different synthetic substances and natural compounds on the development of these two investigated pathogens. The fungicidal agents employed comprised fosetyl aluminum at a concentration of 0.3%, azoxystrobin at 0.2%, and metiram at 0.3%, while the natural extracts investigated included those derived from European birthwort, celandine and sage, each tested at concentrations of 0.5%, 2%, 9%, and 15%. The assessment of mycelial growth inhibition was conducted utilizing Vincent’s formula. Additionally, the total polyphenol content (TPC) within the extracts was determined via the Folin-Ciocalteu spectrophotometric method in accordance with Frum et al. (2022). Furthermore, the antioxidant capacity of the extracts was evaluated using the DPPH radical scavenging method (2,2-diphenyl-1-picrylhydrazyl) and high-performance liquid chromatography (HPLC). Our research findings yielded noteworthy results, specifically, extracts derived from sage and celandine, particularly when present at a concentration of 15%, exhibited a fungistatic effect. This effect was particularly remarkable when compared to the performance of the synthetic fungicide azoxystrobin at a concentration of 0.2% when challenged with the Alternaria pathogen. These results suggest the potential utility of sage and celandine extracts as eco-friendly alternatives for mitigating fungal pathogens in tomato crops, warranting further investigation and consideration within agricultural practices.

Obtaining and research of callus biomass of some plants of the family Ranunсulaсаe

Introduction: Research among the Ukrainian (Carpatian) flora’s representatives is important for searching for new active compounds.Objective: The study aims to determine the potential of callus biomass of Delphinium elatum, Anemone nemorosa, and Pulsatilla alba to become an analog of medicinal plant raw material for the use in the pharmaceutical industry, to investigate the composition, antioxidant activity and antimicrobial activity of extracts of the callus biomass of the above-mentioned plants.Methods: The individual members of the family Ranunculaceae (Delphinium elatum L., Anemone nemorosa L., Pulsatilla alba Rchb.) were introduced into in vitro culture, and their callus induction was studied using the Folin-Ciocalteu spectrophotometric method, colorimetric analysis, antioxidant, and antimicrobial activity methods.Results: The maximum content of flavonoids and phenolic compounds was observed in 40% hydro-ethanolic extracts of callus biomass and plant raw materials of D. elatum. 90.0% and 70.0% D. elatum extracts showed significant activity against Gram-positive microorganisms. 90.0/70.0/40.0% extracts showed significant activity against Bacillus licheniformis. 70.0 % extract showed significant antifungal activity against clinical and reference strains of Candida albicans. Conclusion: Summarizing experimental results, it was proved that the callus biomass of D. elatum, A. nemorosa, and P. alba have potential as analogs of medicinal plant raw materials, both for the content of biologically active substances and biological activities.

Antimicrobial activity of selected plant extracts against common food borne pathogenic bacteria

Increasing antibiotic resistance of important human pathogens calls for investigation and discovery of new antibiotics. Various medicinal plants and spices available in Fiji have antimicrobial potential against various food-borne pathogens. This research aims to address the assumed antimicrobial activity of twelve selected plant extracts against fifteen food-borne pathogens and to evaluate the pathogens resistances. The Kirby-Bauer Method was used in this study to determine the potency of plant extracts. Total Phenolic Content (TPC) was determined by the Folin-Ciocalteu Spectrophotometric method. The chosen plant species samples used were Morinda citrifolia (noni) leaves, Syzygium aromaticum (clove) bud, Psidium guajava (guava) leaves, Ocimum basilicum (basil) leaves, Carica papaya (pawpaw) leaves, Azadirachta indica (neem) seed oil, Citrus limon (lemon) leaves, and Zingiber officinale (ginger) root. Extracts from these eight plants were tested against common food-borne bacteria; Clostridium perfringens, Citrobacter youngae, Enterobacter aerogenes, Enterobacter amnigenus, Enterobacter cloacae, Escherichia coli, Hafnia alveia, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus vulgaris, Proteus mirabilis, Photobacterium damselae, Raoultella ornithinolytica and Vibrio alginolyticus. Both resistance and antibacterial responses were observed for the different plant extracts. All plant extracts were successful in inhibiting bacterial growth for different number of species at varying levels of effectiveness with noni being the most effective. The highest inhibition zones (ZOI>14 mm) were shown by garlic, basil, jasmine and neem. Highest mean ZOI was shown by noni at 11.4 mm followed by garlic at 10.1 mm and clove at 8.4 mm. Minimum inhibitory concentrations were determined for extracts exhibiting antibacterial potential. TPC may attribute to the antibacterial properties of the extracts, however, this needs further investigation. Results indicate presence of possible bioactive compounds in the extracts which can aid in search for new antibiotic drugs from plant sources. Studies that identify the compounds of therapeutically important flora in Fiji is recommended.

Total urinary polyphenol excretion: a biomarker of an anti-inflammatory diet and metabolic syndrome status

BackgroundChronic inflammation is associated with noncommunicable diseases, including obesity, metabolic syndrome (MetS), and CVDs. The Mediterranean diet has been shown to have strong anti-inflammatory effects, attributed in part to the polyphenol richness of many of its components. ObjectivesThis study aimed to assess the value of polyphenols as a urinary biomarker of an anti-inflammatory diet and their influence on MetS status. MethodsA longitudinal analysis was performed in Spain considering 543 participants with high CVD risk in a PREDIMED study. Approximately 52% of the participants were women and 48% were men with a mean age of 67.5 (5.9) y. Total polyphenol excretion (TPE) in urine was determined at baseline and 5 y of intervention using a validated Folin–Ciocalteu spectrophotometric method, and the dietary inflammatory index (DII) was calculated from a validated 137-item food-frequency questionnaire. Three categories were built according to tertiles of change in the DII score. Multivariable linear regression analyses were performed to assess the association of changes in TPE with changes in the DII scores and with MetS status at 5 y. ResultsTertiles 2 and 3 compared with tertile 1 presented a lower anti-inflammatory potential of the diet and were inversely associated with TPE in women [−0.30 mg gallic acid equivalent (GAE)/g creatinine; 95% CI: −0.46, −0.15; P value = 0.006 and −0.29 mg GAE/g creatinine; 95% CI: −0.43, −0.15; P value = 0.005], respectively. The mean changes in TPE were 7.9 (56.1) mg GAE/g creatinine in women and 7.7 (48.2) mg GAE/g creatinine in men. In addition, TPE was inversely associated with changes in MetS status [−0.06 (−0.09; −0.02), P value = 0.009] in both men and women. ConclusionsUrinary polyphenols may be a potential biomarker of anti-inflammatory diet consumption in women and are prospectively associated with improvement in MetS.

Antioxidant and Cytotoxic Activities of Pulicaria dysenterica Methanol Extracts

Aims: The aims of the study were to analyse the polyphenols of Pulicaria dysenterica (L.) Bernh. methanolic extracts from aerial and underground parts, assessment of antioxidant activity and to evaluate their cytotoxicity on HeLa cells of cervical cancer.
 Methodology: The total phenolic content (TPC) of extracts was determined by the Folin-Ciocalteu spectrophotometric method. The qualitative and quantitative analysis of individual polyphenolic compounds were performed by the reverse phase HPLC method. The antioxidant capacity was evaluated by both, 2,2-diphenyl1-picrylhydrazyl radical and FRAP assay, while cytotoxicity of the extracts was assessed by MTT assay.
 Results: TPC of the samples were 127.62±2.22 and 244.12±8.84 mg gallic acid equivalent/g extract. In the extracts chlorogenic acid in amount of 10.06±0.96 and 11.32±0.28 mg/g, flavonoid rutin in amount of 5.68±0.13 mg/g and three caffeic acid derivatives were recorded. Extract from underground parts achieved better antioxidant activity with IC50 value 55.36±0.75 µg/mL and FRAP value 2411.12±37.22 µmol Fe2+g-1 compared to the one from aerial parts. Extract from aerial parts achieved better cytotoxic activity with 50% inhibition of viability (IC50) at concentration of 0.389±0.07 mg/mL, against HeLa cells, compared to the extract from underground parts.
 Conclusion: Analyzed Pulicaria dysenterica extracts contained phenolic acids and flavonoids. The extracts showed good antioxidant activity and cytotoxic properties against HeLa cells in vitro.

Assessment of Bioactive Compounds in Red Wines Available for Purchase in Latvia

Abstract Moderate consumption of wine is associated with positive health effects. Red wine contains more polyphenolic compounds than white wine, so it is considered healthier. The aim of the study was to determine the concentration of bioactive compounds of red grape and berry wines available for purchase in Latvia. A selection of 15 red grape and berry wines purchased in Latvian supermarkets were analysed. The total phenol concentration was determined using the Folin-Ciocalteu spectrophotometric method with minor modifications. Total flavonoid concentration was determined using the colorimetric flavonoid determination method. Antiradical activity was determined using the DPPH (2,2-diphenyl-1-picrylhydraziyl) reagent and ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation determination method. The results show that the analysed red wine samples can be divided into five clusters according to the concentration of total phenols, flavonoids, and antiradical activity. Cluster 1 separately divided Latvian black chokeberry wine, with high total phenol concentration (TPC) and total flavonoid concentration (TFC), high antiradical activity via the DPPH method, and relatively low antiradical activity via ABTS method. Cluster 4 combined red wines with medium TPC, high TFC and high antiradical activity via both DPPH and ABTS methods, and included grape wines from different countries of origin. Cluster 5 combined red wines with high TPC, medium TFC, and medium antiradical activity via both DPPH and ABTS methods.

Antioxidants and total polyphenols of a black chocolate whit incorporation of unroasted cocoa (Theobroma cacao L.)

Cocoa and its main derivative, chocolate, are an important source of antioxidant compounds for human nutrition. Polyphenols are the main antioxidants present in chocolate and are affected by the industrialisation processes of cocoa beans. In this regard, the effect of incorporating raw cocoa during the final stage of the refining process on the antioxidant capacity and phenolic content of dark chocolate was studied. For this purpose, dark chocolates (70%) were made with the incorporation of raw cocoa paste (10, 20 and 30% w/w) in the final refining stage. The antioxidant capacity of all the treatments was determined by the DPPH (2,2-Diphenyl-1-picrylhydrazyl) method and the total phenolic content by the Folin Ciocalteu spectrophotometric method. It was observed that the incorporation of raw cocoa significantly increases the content of antioxidants and total polyphenols in chocolate. As the dose of raw cocoa increases, the antioxidant activity of the chocolate increases linearly (R2=0.996); on the other hand, the polyphenol content increases exponentially (R2=0.968). Only the lowest dose (10%) doubles the phenolic content and the ratio decreases with higher doses of incorporation. The results suggest that the incorporation of raw cocoa in the formulations makes it possible to obtain chocolates with high phenolic content, improving the technological processes for using cocoa produced in the tropical Andes to develop bioactive chocolates, in line with new consumer demand.

“Massa de Malagueta”: tradition with a twist

Introduction OMS estimates that, in 2010, approximately 600 million people had hypertension (HT) globally. The prevalence of HT in Portugal is between 30 ando 45% and in the Azores is 33.6%. The high salt chilli sauce “Massa de Malagueta (MM)”, widely used in this archipelago, may contribute to this prevalence since excess dietary sodium predisposes to high blood pressure. Objectives Our aims were to reformulate the recipe of MM into a healthier version (lower salt, better ingredients), to determine its organoleptic acceptability, and total antioxidant capacity (TAC) in comparison to the traditional recipe. Methods Traditional version was designed sample A. The healthier version (sample B) was prepared by combining pepper, shredded tomato, dried tomato, garlic, Indian saffron, iodised salt (2.5 g per 100 g) and lemon juice. This was prepared several times prior to the final combination. Then, a sensory test was performed with 50 voluntary participants (84% females and 16% males) with a mean age of 21.84 (± 4.55) years, to evaluate the acceptability of both samples. A Food Neophobia Questionnaire (FNQ) and a Samples Assessment Questionnaire (SAQ) were also applied. TAC was quantified by a Folin–Ciocalteu spectrophotometric method [1]. Results Sample A contains only pepper and salt (14.8 g per 100 g), while sample B presented additional compounds with antioxidant activity. Concerning FNQ and SAQ, the vast majority of participants were willing to try the samples and had considered sample B has a more pleasant smell, taste and texture. Also, sample B presented a higher TAC than sample A (1.5088mg/mL versus 0.6182mg/mL). Conclusion The healthier version of MM presented lower salt (12.5% less) and had higher TAC than the traditional recipe. Also, this version was organoleptically acceptable. The higher TAC may be explained by the ingredients used. This study reveals that modifications of traditional recipes may increase nutritional value without compromising acceptance.

Influence of temperature and light on total phenolic compounds during natural orange juice storage

Introduction Natural orange juice is a phenolic compounds rich beverage, whose disposal on market and food catering has increased with the expansion of the concept of healthy food, raising concerns about the effect of storage on total antioxidant capacity (TAC), and scientific evidence on this is scarce. Regarding TAC, is well established that phenolic compounds account more to it than ascorbic acid [1]. Our aim was to evaluate the concentration of total phenolic compounds (CTPC) in fresh squeezed orange juice and analyse the influence of storage conditions (temperature and light) during 48 h on CTPC. Materials and methods Fresh oranges (Citrus sinensis, variety “Valencia Late”, Portugal) of the same calibre and producer were squeezed aliquoted into 3 glasses stored in different conditions: (1) Room temperature (20 °C) and exposed to sunlight; (2) Room temperature (20 °C) fully wrapped in aluminium; and (3) Refrigerated (1 °C). The procedure was performed according to the methodology described by Keskin-Šašić et al. [2]. CTPC was quantified by Folin-Ciocalteu spectrophotometric method, using gallic acid as standard, at 0, 2.5, 4, 8 and 48 h. (a) Samples preparation: 1 mL of orange juice was diluted from each vial in water, to a volume of 25 mL. Part of solution was centrifuged at 5300 rpm for 20’. The supernatant solution was used to analyse. (b) Determination of CTPC: approximately 0.2 mL of each sample was transferred to test tubes containing 1.0 mL of a dilution of Folin–Ciocalteu reagent in water (1:10). After 10’, 0.8 mL of a sodium carbonate solution (7.5% m/v) was added to the sample. The test tubes were allowed to stand at room temperature for 30’, and then absorbance was measure at 743 nm. CTPC was expressed as equivalents of gallic acid (EGA) in mg/100 ml of squeezed orange juice. Samples’ CTPC was determined from a standard curve of gallic acid varying between 0.2 and 4 mg/L. Results CTPC of recently squeezed fresh oranges was 30.1 mg EGA/100 mL (basal). After 48 h, CTPC decreased in all samples: 38.5% in sample 1 (18.5 mg EGA/100 mL), 28.6% in sample 2 (21.8 mg EGA/100 mL), and 27.6% in sample 3 (21.5 mg EGA/100 mL). The higher variation in CTPC occurred for sample 1, stored at room temperature and exposed to sunlight. Discussion and conclusions: Our results suggest that exposure to sunlight is the variable that most influences the decrease CTPC of the fresh orange juice after 48 h. More studies on the influence of these variables are needed to confirm these results and to increase knowledge about storage of fruit fresh juices, to ensure the nutritional quality of this product. Squeezed orange juice is widely present on markets and coffee shops, usually refrigerated but not protected from sunlight, which means that the storage conditions would need to be reconsidered.

Predisposition of Soybean (Glycine max L.) to the Accumulation of Phenolic Compounds Depending on the Purpose of Its Use

The paper summarizes a 3-year study of the total accumulation of phenolic compounds (PC), which represent the most important group of alcohol- and water-soluble antioxidants, in seeds and vegetative organs of vegetable soybean. The study was carried out using a Folin-Ciocalteu spectrophotometric method. Oil-bearing and vegetable soybean samples were grown in a greenhouse and on the experimental field of the Federal Scientific Center for Vegetable Growing (Moscow oblast). PC accumulation in the phases of the technical (R6) and biological (R8) ripeness of vegetable soybean varieties was first studied under conditions of the northern border of the crop cultivation zone (55° N). The PC content in vegetative organs of plants at the R6 phase significantly exceeded that in seeds (12.0 and 4.1 mg/g of dry weight, respectively). In both R6 and R8 phases, accumulation of phenolic compounds in seeds of vegetable forms exceeded that in the oilseed varieties by 36.6 and 10%, respectively; the average exceeding at the R8 phase for the 3 years of study was 26.3%. Some vegetable lines, such as Gokuwase Hayabusa Edamame, Sample A, and Tundra, were characterized by a high PC content (4.9 mg/g). The study of accumulation of such compounds in vegetable forms under conditions of the Central region of the Nonchernozem zone showed a high potential of their use for the creation of varieties characterized by a high PC content and suitable for production of functional and medicinal vegetable products.

Comparison of Total Phenolic Content, Antioxidant Activity and Extraction Yield from Apium Graveolens Waste Using Unconventional Extraction Methods

Apium graveolens is a medicinal and aromatic plant used in pharmaceutical industry, cosmetic industry, gastronomy and traditional medicine. Aerial parts of Apium graveolens (stems and leaves) are rich in bioactive compounds (flavonoids, phenols, furanocoumarins, volatile oils, sesquiterpene alcohols, fatty acids, etc.). It is known for its hepatoprotective, antioxidant, anticancer, antidiabetic, anti-inflammatory, antimicrobial, analgesic, anti-spasmolytic, anti-infertility, cardiotonic activities. This is why studies in this direction have not yet ceased and are increasingly pursuing the discovery of new, unconventional methods for identifying, quantifying and isolating bioactive compounds from Apium graveolens waste. The aim of this study was to determine and correlate the total phenolics, total flavonoids, antioxidant activity and extraction yield from ethanolic extracts (70%) of stems and leaves waste with different unconventional extraction methods. Apium graveolens aerial parts waste were obtained after aqueous extraction of the leaves and stems. The extraction yield was expressed as function of freeze-dried extracts, and the extraction methods were ultrasound assisted extraction, microwave assisted extraction and accelerated solvent extraction. Regarding the chosen extraction methods, numerous studies have shown, especially in the case of microwave assisted extraction, the presence of bioactive compounds in plant waste, in a reasonable percentage, therefore this study aimed to identify an optimal extraction method also in the case of Apium graveolens aerial parts waste. Total phenols content was determined by Folin-Ciocalteu spectrophotometric method, the flavonoids content waste determined by aluminium chloride spectrophotometric method and the antioxidant activity was studied using DPPH (2,2-Diphenyl-1-picrylhydrazyl) spectrophotometric method. The findings of this work indicated a positive dependence between the extraction yield of the waste material and the considerable content of bioactive compounds still present (phenols and flavonoids) for all considered extraction methods.

Tannin profile, antioxidant properties, and antimicrobial activity of extracts from two Mediterranean species of parasitic plant Cytinus

BackgroundCytinus is small genus of endophytic parasitic plants distributed in South Africa, Madagascar, and in the Mediterranean region. In the latter area, two species occur, Cytinus hypocistis and C. ruber, distinguished by both morphological characters and ecological traits. We characterized the ethanolic and aqueous extracts obtained from the inflorescences of C. hypocistis and C. ruber collected in Sardinia, Italy, and explored their tannin content, antioxidant properties and antimicrobial activities.MethodsTotal phenolic contents were determined by Folin-Ciocalteu spectrophotometric method. Tannin content was determined by HPLC. Antioxidant activity of the extracts was tested with both electron transfer-based (FRAP, TEAC, DPPH) and spectrophotometric HAT methods (ORAC-PYR). The antimicrobial activities of extracts/compounds were evaluated using the broth microdilution method. The bactericidal activity was evaluated using the time-kill method. Biofilm formation was evaluated by crystal violet (CV) staining assay.ResultsCharacterization of the tannin profile of C. hypocistis and C. ruber revealed a significant amount of gallotannins, in particular 1-O-galloyl-β-D-glucose. In addition, pentagalloyl-O-β-D-glucose was present in all extracts, reaching the concentration of 0.117 g/kg in the ethanolic extract of C. hypocistis. C. hypocistis extracts displayed a strongest antioxidant activity than C. ruber extracts. Three Gram-positive bacterial species tested (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium) resulted sensitive to both Cytinus extracts, with MICs ranging from 125 to 500 μg/ml for aqueous extracts and from 31.25 to 250 μg/ml for ethanolic extracts; on the contrary, Gram-negative strains (Pseudomonas aeruginosa and Klebsiella pneumoniae) were not affected by Cytinus extracts. Intriguingly, we observed the suppressive activity of ethanolic extracts of C. hypocistis and C. ruber on biofilm formation of S. epidermidis. Experiments performed with synthetic compounds indicated that pentagalloyl-O-β-D-glucose is likely to be one of the active antimicrobial components of Cytinus extracts.ConclusionsThese findings show that Cytinus extracts have antimicrobial and antioxidant activities, suggesting a possible application of Cytinus as sources of natural antimicrobials and antioxidants.

Hard Cap Espresso Machine Extraction of Polyphenolic Compounds from Pulses

A hard cap espresso machine was employed for the extraction of polyphenolic compounds from food samples as dry legumes and pulses. 100 mg of ground dry sample was mixed with a dispersing agent and placed in a refillable stainless steel capsule with a borosilicate filter. A complete polyphenol extraction was achieved by using 150 mL ethanol 50 % (v/v) in water and determined by Folin-Ciocalteu spectrophotometric method. The method provided a limit of detection of 0.4 mg g<sup>-1</sup>. The whole extraction procedure was achieved in less than one minute using the mild extraction conditions of 72°C and 19 bars given by the domestic machine. Fifteen varieties of food samples (3 lentils, 6 beans, 5 chickpeas, and 1 sorghum) were purchased in Spanish and Tunisian markets and analyzed by the proposed procedure. Obtained results were compared with those found by a reference extraction method based on ultrasound-assisted extraction, being statistically comparable. The content of polyphenolic compounds in the analyzed commercial samples varied from 4.6 to 5.5 mg g<sup>-1</sup> for lentils, from 3.4 to 5.8 mg g<sup>-1</sup> for beans, from 2.2 to 3.5 mg g<sup>-1</sup> for chickpeas, and 3.0 mg g<sup>-1</sup> for sorghum.

Phenolic contents, antimicrobial and antioxidant activity of Olea ferruginea Royle (Oleaceae)

BackgroundOlea ferruginea Royle (Oleaceae) has long been used as an important ethnomedicinal plant to cure fever and debility, toothache, hoarseness, throatache and skeleton disorders. In this study, phenolic contents, antimicrobial and antioxidant activities of leaf and bark extracts (chloroform, ethanol and methanol) of O. ferruginea were evaluated.MethodsTotal phenolic contents were determined by Folin-Ciocalteu Spectrophotometric method. Antimicrobial activity was examined against Bacillus subtilis and Staphylococcus aureus (Gram positive), Escherichia coli (Gram negative), Candida albicans and Sccharomyces cerevisiae (yeas strains) by disc diffusion method. Antioxidant activity was observed through DPPH assay.ResultsThe higher phenolic content was found in bark extract (376 μg/mg) of O. ferruginea. Chloroform extracts was found inactive against tested microorganisms while ethanol and methanol extracts showed pronounced inhibitory activity against both gram positive and gram negative bacteria. Only methanol extract of leaves inhibited the yeast strains. None of the bark extract inhibited the growth of tested yeast strains. The zones of inhibition formed by plant extracts were compared with zones of inhibition of available reference antibiotic discs such as tetracycline, ciprofloxacin and nystatin. Higher antioxidant activity was observed with methanol extracts of leaves and bark of O. ferruginea.ConclusionThese findings show that O. ferruginea has potential antimicrobial and antioxidant activities. This study suggests a possible application of olive leaves and bark as sources of natural antimicrobial and antioxidants.

Polyphenol bioavailability in nuts and seeds by an in vitro dialyzability approach

An in vitro dialyzability approach has been undertaken to elucidate the bioavailable fraction of the total polyphenols (TPs) of edible nuts and seeds. The TP contents in samples and in dialyzates were assessed by the Folin-Ciocalteu spectrophotometric method. Antioxidant activity was determined in selected samples, using a modified method against Trolox®. TPs and antioxidant activity in nuts/seeds were determined after applying a pressurized liquid extraction sample pre-treatment. High dialyzability ratios were assessed in most nuts/seeds (TP dialyzability percentages within the 25–91% range). The highest TP dialyzability ratios were found in raw Brazil nuts (81 ± 5%), toasted pistachios (88 ± 9%), and fried cashews (89 ± 9%), whereas TPs in pumpkin seeds were found to be very low (TPs were not detected in the dialyzable fraction). TP dialyzability was correlated with the copper content in nuts and seeds.

The use of macro- and microalgae as functional ingredients in diets for meagre (Argyrosomus regius, Asso 1801)

The use of macro- and microalgae as functional ingredients in diets for meagre (Argyrosomus regius, Asso 1801)

Rapid determination of hydrophilic phenols in olive oil by vortex-assisted reversed-phase dispersive liquid-liquid microextraction and screen-printed carbon electrodes

A novel approach is presented to determine hydrophilic phenols in olive oil samples, employing vortex-assisted reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) for sample preparation and screen-printed carbon electrodes for voltammetric analysis. The oxidation of oleuropein, hydroxytyrosol, caffeic acid, ferulic acid and tyrosol was investigated, being caffeic acid and tyrosol selected for quantification. A matrix-matching calibration using sunflower oil as analyte-free sample diluted with hexane was employed to compensate matrix effects. Samples were analyzed under optimized RP-DLLME conditions, i.e., extractant phase, 1M HCl; extractant volume, 100µL; extraction time, 2min; centrifugation time, 10min; centrifugation speed, 4000rpm. The working range showed a good linearity between 0.075 and 2.5mgL−1 (r = 0.998, N = 7) for caffeic acid, and between 0.075 and 3mgL−1 (r = 0.999, N = 8) for tyrosol. The methodological limit of detection was empirically established at 0.022mgL−1 for both analytes, which is significantly lower than average contents found in olive oil samples. The repeatability was evaluated at two different spiking levels (i.e., 0.5mgL−1 and 2mgL−1) and coefficients of variation ranged from 8% to 11% (n = 5). The applicability of the proposed method was tested in olive oil samples of different quality (i.e., refined olive oil, virgin olive oil and extra virgin olive oil). Relative recoveries varied between 83% and 108% showing negligible matrix effects. Finally, fifteen samples were analyzed by the proposed method and a high correlation with the traditional Folin-Ciocalteu spectrophotometric method was obtained. Thereafter, the concentrations of the fifteen oil samples were employed as input variables in linear discriminant analysis in order to distinguish between olive oils of different quality.

Bioactive Compounds Diffusion from Grapes to Wines under High Frequency Electromagnetic Field Treatments

In this paper, grapes were processed by using high frequency electromagnetic field in order to obtain a high quality wine in terms of bioactive compounds content with antioxidant activity. The experimental setup comprise an applicator with adjustable power between 100-1000 W, software assisted, in order to process three varieties of grapes (Muscat Ottonel, Merlot, Pinot Noir), that were harvested in 2014 in the Crişana-Sântimreu vineyard. The total polyphenol compounds were measured using the Folin-Ciocalteu spectrophotometric method, and the antioxidant capacity was determined by the FRAP method. The results have shown that the use of high frequency electromagnetic field in grape processing leads to the diffusion of the bioactive compounds with antioxidant activity in the final product. In the same time, it is also an effective method in terms of energy consumption.