Composition and biological activities of different extracts of Salvia jurisicii,a rare and endemic Macedonian species

This is the first report on the phenolic composition and biological activities of endemic species Salvia jurisicii Ko?anin (Lamiaceae) originating from Macedonia. Aerial parts of S. jurisicii were extracted with dichloromethane, ethyl acetate, methanol, ethanol and water. All extracts were tested spectrophotometrically for total phenolic and flavonoid contents, while their phenolic composition was analyzed using HPLC-DAD. The antioxidant activity of extracts was studied using 2,2-dyphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ferric reducing ability of plasma and ß-carotene bleaching assays. Being the most frequently used solvents for extraction of bioactive ingredients from medicinal plants, water and ethanol extracts were chosen for further testing of antimicrobial, cytotoxic and antineurodegenerative activities. More polar solvent extracts showed higher total phenolic content and lower flavonoid content. Ethanol and methanol extracts, followed by water extract exhibited the strongest antioxidant activity. Extracts showed antimicrobial activity against certain bacteria and micromycetes. The cytotoxicity assay showed slight toxicity to HCT-116 cell line. In the antineurodegenerative assays, the extracts performed lower inhibition of acetylcholinesterase and tyrosinase than standards. According to the results of this study, it can be inferred that more polar extracts of S. jurisicii were quantitatively richer in total phenolics, showing stronger antioxidant activity. Ethanol extract showed stronger biological activities comparing to water extract.     

Phenolic composition and antioxidant activities of two Phlomis species: A correlation study

Two traditional Chinese medicines (Phlomis umbrosa Turcz. and Phlomis megalantha Diels), as well as five pure phenolic compounds (protocatechic, chlorogenic, benzoic, rosmarinic acid, and rutin) have been studied for antioxidant activities in acetone and methanol extracts from leaves. An HPLC method was developed to quantify the amounts of 14 phenolic compounds in the leaf extracts. The antioxidant capacities of the studied species are high. Almost all samples were capable of directly scavenging DPPH and superoxide free radicals, inhibiting linoleic acid oxidation, acting as reducing agents, and reducing plasmid DNA damage induced by hydroxyl radicals. Among different extracts, the acetone extract of P. megalantha exhibited the highest antioxidant activity. The major phenolic compounds identified were protocatechic, chlorogenic, caffeic, rosmarinic acid, and (−)-epicatechin. Antioxidant activities of pure compounds and correlation analysis indicated that protocatechic and rosmarinic acids were the major contributors to the observed antioxidant activities of the investigated Phlomis extracts. To cite this article: Y. Zhang, Z.-z. Wang, C. R. Biologies 332 (2009).     

Alterations in Endogenous Levels of Gibberellin-like Substances during Germination of Phaseolus vulgaris Seeds

The endogenous gibberellin-like substances were determined in mature dry and germinating bean seeds, Phaseolus vulgaris L. cv. Alabaster. Methanol extracts were partitioned against ethyl acetate and butanol at neutral and acid pH. Each phase was individually chromatographed on a silica gel column. The gibberellin activity was measured with the Tan-ginbozu dwarf rice micro-drop bioassay. Each extract was tested in two dilutions. Extracts from dry seeds showed the highest gibberellin activity, largely attributable to ethyl acetate-soluble substances. The activity was considerably reduced in extracts from seeds imbibed for 1 day. Gibberellin-like substances soluble in butanol appeared in extracts from seeds soaked for 1 or more days.     

HPLC/HR-MS-Based Metabolite Profiling and Chemometrics: A Powerful Approach to Identify Bioactive Compounds from Abarema cochliacarpos

Despite its importance as a medicinal plant, there is a lack of studies that assessed the chemical composition of A. cochliacarpos extracts. Herein, we used a metabolite profiling approach and chemometrics as a powerful strategy to correlate the chemical composition with the antioxidant activity of A. cochliacarpos extracts. Extracts obtained with ethyl acetate showed greater antioxidant activity and higher total phenolic content than extracts obtained with hexane. The chemical composition was assessed by HPLC/HR-MS and it encompassed fatty alcohols, terpenoids, phenolic derivatives, lipids, carotenoid-like compounds, alkaloids, flavonoids, polyketides, and glycerophospholipids. Chemometrics successfully differentiated not only the chemical composition of extracts in response to the nature of the extraction solvent and the botanical part used during extraction but also it allowed us to associate the chemical composition with the antioxidant activity of the extracts, which might be particularly helpful for drug discovery and development programs.     

Caesalpinia palmeri: First Report on the Phenolic Compounds Profile,Antioxidant and Cytotoxicity Effect

This study aimed to determine the phenolic compounds profile, antioxidant potential and cytotoxicity of extracts and fractions of Caesalpinia palmeri. Methanolic extracts were generated from C. palmeri berries, stems and flowers. The latter was subjected to liquid-liquid partition, obtaining hexane, ethyl acetate and residues fractions. Results showed that the flower extract and ethyl acetate fraction had a larger concentration of phenolic compounds (148.9 and 307.9 mg GAE/g, respectively), being ellagic acid (6233.57 and 19550.08 μg/g, respectively), quercetin-3-β-glycoside (3023.85 and 8952.55 μg/g, respectively) and gallic acid (2212.98 and 8422.34 μg/g, respectively) the most abundant compounds. Flower extract and ethyl acetate fraction also presented the highest antioxidant capacity on all tested methods (DPPH, ABTS, ORAC and FRAP) and low cytotoxicity against ARPE-19 cells (IC₅₀ >170 μg/mL). C. palmeri possessed high antioxidant potential, associated with the presence of phenolic compounds and low cytotoxicity, suggesting that they could represent an option to counter oxidative stress.     

Chemical Composition and Pharmacological Evaluation and of Toddalia asiatica (Rutaceae) Extracts and Essential Oil by in Vitro and in Silico Approaches.

Toddalia asiatica (L.) Lam. is extensively used in traditional medicinal systems by various cultures. Despite its frequent use in traditional medicine, there is still a paucity of scientific information on T. asiatica growing on the tropical island of Mauritius. Therefore, the present study was designed to appraise the pharmacological and phytochemical profile of extracts (methanol, ethyl acetate and water) and essential oil obtained from aerial parts of T. asiatica. Biological investigation involved the evaluation of in vitro antioxidant and enzyme inhibitory potentials. The chemical profile of the EO was determined using gas chromatography coupled to mass spectrometry (GC/MS) analysis, while for the extracts, the total phenolic (TPC) and flavonoid content were quantified as well as their individual phenolic compounds by LC/MS/MS. Quinic acid, fumaric acid, chlorogenic acid, quercitrin and isoquercitrin were the main compounds in the extracts. Highest total phenolic (82.5±0.94 mg gallic acid equivalent (GAE/g)) and flavonoid (43.8±0.31 mg rutin equivalent (RE/g)) content were observed for the methanol extract. The GC/MS analysis has shown the presence of 26 compounds with linalool (30.9 %), linalyl acetate (20.9 %) and β-phellandrene (7.9 %) being most abundant components in the EO. The extracts and EO showed notable antioxidant properties, with the methanol extract proved to be superior source of antioxidant compounds. Noteworthy anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BChE) effects were recorded for the tested samples, while only the methanol and ethyl acetate extracts were active against tyrosinase. With respect to antidiabetic effects, the extracts and EO were potent inhibitors of α-glucosidase, while modest activity was recorded against α-amylase. Docking results showed that linalyl acetate has the highest affinity to interact with the active site of BChE with docking score of −6.25 kcal/mol. The findings amassed herein act as a stimulus for further investigations of this plant as a potential source of bioactive compounds which can be exploited as phyto-therapeutics.     

Biologically active compounds from two members of the Asteraceae family: Tragopogon dubius Scop. and Tussilago farfara L.

Tragopogon dubius and Tussilago farfara are consumed as vegetables and used in folk medicine to manage common diseases. Herein, the chemical compositions and biological activities of different leaf extracts (ethyl acetate, methanol, and water) of T. dubius and T. farfara were evaluated. The antibacterial, antifungal, and antioxidant abilities of the extracts were tested using different assays including free radical scavenging, reducing power, phosphomolybdenum, and metal chelating assays. Enzyme inhibitory potentials were evaluated against cholinesterases, tyrosinase, α-amylase and α-glucosidase. Complexes of bioactive compounds (chlorogenic and rosmarinic acid) were docked into the enzymatic cavity of α-glucosidase and subjected to molecular dynamic calculation, enzyme conformational stability, and flexibility analysis. T. dubius and T. farfara extracts showed remarkable antioxidant potentials. Ethyl acetate extracts of T. dubius and T. farfara were the most potent inhibitors of acetylcholinesterase and butyrylcholinesterase. T. dubius ethyl acetate extract and T. farfara methanolic extract showed noteworthy activity against α-glucosidase. High performance liquid chromatography analysis revealed the abundance of some phenolic compounds including chlorogenic and rosmarinic acids. Ethyl acetate extract of T. dubius showed notable antifungal activity against all strains. Docking studies showed best pose for chlorogenic acid was stabilized by a network of hydrogen bonds with residues Asp1157, Asp1279, whereas rosmarinic acid showed several hydrogen bonds with Asp1157, Asp1420, Asp1526, Lys1460 and Trp1369. This study further validates the use of T. dubius and T. farfara in traditional medicine, as well as act as a stimulus for further studies for future biomedicine development.

Communicated by Ramaswamy H. Sarma     

Efficient release of ferulic acid from sweet potato (<Emphasis Type="Italic">Ipomoea batatas</Emphasis>) stems by chemical hydrolysis

An efficient method for release of ferulic acid from sweet potato stems was developed. Ferulic acid along with phenolic compounds were released from stems by acid and alkaline treatments. The base hydrolysis with 0.1 N NaOH yielded the highest quantity of total extracts (471.1 mg/g). The stems released more phenolic compounds when 0.0125∼0.025 N NaOH was employed. Where as ferulic acid release was maximal with 0.05 N H₂SO₄ (0.32 mg/g). Ferulic acid was separated from phenolics by column chromatography. Among the elution solvents, ethyl acetate fractions (80%) contained ferulic acid. Ethyl acetate eluants were further fractionated with n-hexane/ethyl acetate/formic acid (100/50/0.5, v/v/v). All fractions showed ferulic acid and phenolic compounds. Fraction V among them was ascribed to ferulic acid with an yield of 5.41 mg/g of dry sweet potato tissue.     

Chemical Characterization of Different Extracts from Artemisia annua and Their Antioxidant,Enzyme Inhibitory and Anti-Inflammatory Properties

Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract ; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.     

菹草提取物总黄酮、总酚酸和抗氧化活性含量研究

研究菹草提取物的有效成分,测定其总黄酮含量及总酚酸含量,并确定它的乙酸乙酯和石油醚部位的抗氧化活性成分。采用紫外可见分光光度法,以芦丁和没食子酸作为控制材料,测定菹草的石油醚部位及乙酸乙酯部位中总黄酮和总酚酸含量;采用清除DPPH自由基能力测定法、测定总还原能力铁氰化钾法和水杨酸捕捉羟基自由基法来对菹草各组分提取物的抗氧化能力进行研究。菹草中有一定量的黄酮类化合物和酚酸类化合物存在,不同溶剂提取的部位所含有的总黄酮和总酚酸含量是有差异的,石油醚部位的总黄酮含量要高于乙酸乙酯部位的总黄酮含量,并且总酚酸的含量亦是如此;石油醚部位和乙酸乙酯部位的提取物具有清除DPPH、羟基自由基和还原Fe^3+的能力,各部位清除DPPH、羟基自由基的能力和还原Fe^3+的能力随着样品浓度的增大而增大,且乙酸乙酯部位的测定结果均低于石油醚部位。     

益智的抗氧化作用

本文探讨了益智(Alpinia oxyphylla Miquel)超临界CO2提取物及其渣的水提物、正丙醇提取物和乙酸乙酯提取物的抗氧化作用,测定了总酚含量、黄酮含量、抗氧化力、还原能力、DPPH清除率.结果表明,益智超临界CO2提取物和正丙醇提取物的总酚含量最高,均为5.53%,乙酸乙酯提取物的总酚含量为4.04%,水提物总酚含量最低,为O.89%.抗氧化力与酚含量相关(R2=0.703).四种提取物中黄酮含量顺序为:乙酸乙酯提取物(6.29%)＞丙醇提取物(5.81%)＞水提取物(4.85%)＞超临界CO2提取物(4.70%).在还原能力、清除DPPH自由基和羟自由基方面,乙酸乙酯提取物表现出了很强的抗氧化能力,呈现剂量依赖关系.     

加拿大一枝黄花提取物的抗氧化活性研究

为进一步开发和利用加拿大一枝黄花(Solidago canadensis),该研究采用氯化铝显色法和福林酚法测定加拿大一枝黄花乙醇提取物及其不同极性萃取物中的总黄酮和总酚的含量;以抗坏血酸(Vitamin C,Vc)和二丁基羟基甲苯(BHT)为阳性对照,应用2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)、1,1-二苯基苦基苯肼(DPPH)自由基清除体系、铁离子还原能力(FRAP)法和抗氧化能力指数(ORAC)法研究其体外抗氧化活性。结果表明:乙酸乙酯萃取物中的总黄酮(202.45 mg·g~(-1))和总酚(485.94 mg·g~(-1))含量最高,且其抗氧化活性最强,并强于阳性对照Vc(P0.05)。因而,加拿大一枝黄花乙酸乙酯萃取物将有可能成为一种潜在的天然高效抗氧化剂,具有广泛的应用前景。     

Myrtus communis berry color morphs: a comparative analysis of essential oils, fatty acids, phenolic compounds, and antioxidant activities

Extracts of mature dark blue and white berries from two Tunisian Myrtus communis morphs growing at the same site were assessed for their essential‐oil and fatty‐acid compositions, phenolic contents, and antioxidant activities. The GC and GC/MS analyses of the essential oils allowed the identification of 33 constituents. The oils from the dark blue fruits showed high percentages of α‐pinene (11.1%), linalool (11.6%), α‐terpineol (15.7%), methyl eugenol (6.2%), and geraniol (3.7%). Myrtenyl acetate (20.3%) was found to be the major compound in the oils from white berries. GC Analysis of the pericarp and seed fatty acids showed that the polyunsaturated fatty acids constituted the major fraction (54.3–78.1%). The highest percentages of linoleic acid (78.0%) and oleic acid (20.0%) were observed in the seeds and the pericarps of the white fruits, respectively. The total phenol, flavonoid, and flavonol contents and the concentration of the eight anthocyanins, identified by HPLC analysis, were significantly higher in the dark blue fruits. All extracts showed a substantial antioxidant activity, assessed by the free radical‐scavenging activity and the ferric reducing power, with the dark blue fruit extracts being more effective.     

Phytochemical Composition and Antioxidant Activities of the Essential Oil and Extracts of Satureja subspicata Vis. Growing in Bosnia and Herzegovina

The phytochemical composition and the antioxidant activities of the essential oil, as well as methanol and hot water extracts of endemic Satureja subspicata Vis . growing in Bosnia and Herzegovina (BiH), were described. β‐Caryophyllene, cis‐β‐ocimene, and α‐pinene, identified by GC/MS and GC‐FID, were the dominant oil components. The major compound of both of extracts, identified by HPLC‐DAD, was rosmarinic acid. The analyzed essential oil showed moderate antioxidant activity. In this first report on the extracts of S. subspicata growing in BiH, the obtained results showed a high content of rosmarinic acid, as well as considerable amount of total phenols and flavonoids. Compared to the hot water extract, the methanol extract exhibits higher antioxidant potential, measured by DPPH and FRAP assay (IC₅₀ = 0.45 g/l and 1879.43 equiv. Fe²⁺ μm ), while the hot water extract showed higher potential in inhibition of linoleic acid oxidation (51.7% and 61.5% for 1 and 10 g/l). A good antioxidant potential of the tested extracts indicates their potential use as antioxidants, particularly for lipid protection, and partly explains the justification of the use of this plant in traditional medicine of BiH.     

Antimicrobial activity,total phenolic content and flavonoid concentrations of <Emphasis Type="Italic">Teucrium</Emphasis> species

In vitro antimicrobial activity of 21 crude extracts obtained from seven taxa of the genus Teucrium (T. chamaedrys, T. montanum, T. arduini, T. polium, T. scordium subsp. scordium, T. scordium subsp. scordioides and T. botrys) was tested against bacterial and fungal species. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using a microdilution analysis method. Total phenolic content and flavonoid concentrations were measured spectrophotometrically. Total phenols were determined using Folin-Ciocalteu reagent and their amounts ranged from 28.49 up to 159.84 mg CA/g of extract (chlorogenic acid equivalent). The amounts of flavonoids ranged from 38.17 up to 190.45 mg RU/g of extract (rutin equivalent).The plant extracts showed greater potential of antibacterial than antifungal activity. A relationship was found between total phenolics and biological activity. The highest level of total phenols was measured in the methanol extracts, which demonstrated higher antimicrobial activity than acetone and ethyl acetate extracts. Staphylococcus aureus ATCC 25923 appeared to be the most sensitive organism. Our results indicate that Teucrium spp extracts are rich sources of phenolic compounds and are promising candidates for further development as natural antimicrobial agents.     

Antioxidant and antimicrobial activities of rosemary extracts linked to their polyphenol composition

Rosmarinus officinalis extracts were investigated by a combination of bioassays and biochemical analysis to identify bioactive compounds. The 2,2-diphenyl-2-picrylhydracyl hydrate (DPPH) radical scavenging method, Folin–Ciocaulteau method and HPLC chromatography were used to study the distribution and levels of antioxidants (AOXs). Antimicrobial activity analysis was carried out using the disk diffusion and broth dilution techniques. A good correlation between the AOX activities and total phenol content in the extracts was found. Although all rosemary extracts showed a high radical scavenging activity, a different efficacy as antimicrobial agent was observed. Methanol extract containing 30% of carnosic acid, 16% of carnosol and 5% of rosmarinic acid was the most effective antimicrobial against Gram positive bacteria (minimal inhibition concentration, MIC, between 2 and 15 μg/ml), Gram negative bacteria (MIC between 2 and 60 μg/ml) and yeast (MIC of 4 μg/ml). By contrast, water extract containing only 15% of rosmarinic acid showed a narrow activity. MIC value of the methanol and water extracts is in a good correlation with the values obtained with pure carnosic acid and rosmarinic acid, respectively. Therefore, our results suggested that the antimicrobial rosemary extracts efficacy was associated with their specific phenolic composition. Carnosic acid and rosmarinic acid may be the main bioactive antimicrobial compounds present in rosemary extracts. From a practical point of view, rosemary extract may be a good candidate for functional foods as well as for pharmaceutical plant-based products.     

The Use of NMR Metabolite Profiling and in vivo Hypoglycemic Assay for Comparison of Unfractionated Aqueous Leaf Extracts of Two Ocimum Species

Ocimum basilicum and Ocimum gratissimum (Lamiaceae) are used to treat diabetes mellitus in Africa. In a previous work, we identified chicoric acid as a hypoglycemic substance in O. gratissimum. This study aims to compare the chemical metabolite profile and the hypoglycemic activity of unfractionated aqueous extracts from leaves of both Lamiaceae species. The metabolite composition of OB and OG decoctions (10% w/v) was analyzed using HPLC‐DAD and NMR tools. Chicoric acid showed to be the major phenolic in both extracts, besides caftaric, caffeic, and rosmarinic acids; nevertheless, there is approximately three times more of this substance in OG. From 1D‐ and 2D‐NMR analyses, 19 substances were identified in OB, while 12 in OG. The in vivo acute hypoglycemic activity of the extracts was assessed intraperitoneally in streptozotocin (STZ)‐induced diabetic mice. The doses of 100 and 200 mg/kg of both extracts significantly reduced their glycemia, compared to controls (P < 0.05). OB was a little more effective than OG, despite the lower content of chicoric acid in OB. This result strongly suggests that components other than chicoric acid contribute to the hypoglycemic activity of the two extracts. Despite the abundance of caffeic and rosmarinic acids in OB, their hypoglycemic activity observed at 8.3 μmol/kg was low. This is the first chemical profile of crude extracts from Ocimum species by NMR. Our findings confirmed the potential of both species in DM treatment in spite of marked differences in their chemical composition. However, long‐term studies are necessary in order to identify the most promising of the two species for the development of an herbal medicine.     

Chemical Composition and Antioxidant Activity of Essential Oils and Methanol Extracts of Different Parts from Juniperus rigida Siebold & Zucc.

The chemical composition and antioxidant activity of essential oils and MeOH extracts of stems, needles, and berries from Juniperus rigida were studied. The results indicated that the yield of essential oil from stems (2.5%) was higher than from needles (0.8%) and berries (1.0%). The gas chromatography/mass spectrometer (GC/MS) analysis indicated that 21, 17, and 14 compounds were identified from stems, needles, and berries essential oils, respectively. Caryophyllene, α‐caryophyllene, and caryophyllene oxide were primary compounds in both stems and needles essential oils. However, α‐pinene and β‐myrcene mainly existed in berries essential oils and α‐ionone only in needles essential oils. The high‐performance liquid chromatography (HPLC) analysis indicated that the phenolic profiles of three parts exhibited significant differences. Needles extracts had the highest content of chlorogenic acid, catechin, podophyllotoxin, and amentoflavone, and for berries extracts, the content of those compounds was the lowest. Meanwhile, three in vitro methods (DPPH, ABTS, and FRAP) were used to evaluate antioxidant activity. Stems essential oil and needles extracts exhibited the powerful antioxidant activity than other parts. This is the first comprehensive study on the different parts of J. rigida. The results suggested that stems and needles of J. rigida are useful supplements for healthy products as new resources.     

Phenolic composition and antioxidant properties of some traditionally used medicinal plants affected by the extraction time and hydrolysis

Introduction – Polyphenolic phytochemicals in traditionally used medicinal plants act as powerful antioxidants, which aroused an increasing interest in their application in functional food development. Objective – The effect of extraction time (5 and 15 min) and hydrolysis on the qualitative and quantitative content of phenolic compounds and antioxidant capacity of six traditionally used medicinal plants (Melissa officinalis L., Thymus serpyllum L., Lavandula officinalis Miller, Rubus fruticosus L., Urtica dioica L., and Olea europea L.) were investigated. Methodology – The content of total phenols, flavonoids, flavan‐3‐ols and tannins was determined using UV/Vis spectrophotometric methods, while individual phenolic acids, flavones and flavonols were separated and detected using HPLC analysis. Also, to obtain relevant data on the antioxidant capacity, two different assays, (2,2‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid) (ABTS) radical scavenging and ferric reducing/antioxidant power (FRAP) assays were used. Results – The extraction efficiency of phenolics, as well as the antioxidant capacity of plant extracts, was affected by both prolonged extraction and hydrolysis. The overall highest content of phenolic compounds was determined in hydrolyzed extract of blackberry leaves (2160 mg GAE/L), followed by the non‐hydrolyzed extract of lemon balm obtained after 15 min of extraction (929.33 mg GAE/L). The above extracts also exhibited the highest antioxidant capacity, while extracts of olive leaves were characterized with the lowest content of phenolic compounds, as well as the lowest antioxidant capacity. The highest content of rosmarinic acid, as the most abundant phenolic compound, was determined in non‐hydrolyzed extract of lemon balm, obtained after 15 min of extraction. Although the hydrolysis provided the highest content of polyphenolic compounds, longer extraction time (15 min) was more efficient to extract these bioactives than shorter extraction duration (5 min). Conclusion – The distribution of detected phenolic compounds showed a wide variability with regard to their botanical origin. Examined medicinal plants showed to be a valuable supplement to a daily intake of bioactive compounds. Copyright © 2010 John Wiley & Sons, Ltd.     

Recovery of phenolic antioxidants from wine industry by-products

The recovery process of the phenolic compounds contained in the wine industry by-products and their antioxidant activity were examined in this work. To this purpose, a combined process of liquid and supercritical solvent extraction was employed. At first the effect of various process parameters of the liquid solvent extraction--the type of solvent and the pretreatment of the raw material (composition (skins, seeds, stems) and crushing)--on the antioxidant activity of the extract was examined. It was shown that an extract of a higher antioxidant activity was obtained by using ethyl acetate as solvent and raw material free of stems. These extracts were further treated with supercritical carbon dioxide (SC CO(2)) at various extraction pressures, which resulted in their significant enrichment in phenolic compounds and the improvement of their antioxidant and organoleptic properties, especially at pressures higher than 100 bar. The antioxidant activity of the products was determined by using the Rancimat method, as well as a simple and not time-consuming free radical method. It was proved that both the ethyl acetate extracts and those treated with SC CO(2) had antioxidant activity comparable to that of antioxidants commonly used in industry, that is butylhydroxytoluene (BHT), a synthetic antioxidant, and Rosemary extract, a widely known natural one.