Phenolic Compound Identification and Antioxidant Capacity of Alperujo Extracts from Region del Maule,Chile

This study was carried out to determinate phenolic, flavonoid content, and antioxidant capacity in methanolic extract from three Alperujo varieties. Alperujo Barnea showed the highest concentration of phenols and flavonoid. The greater hydroxytyrosol content was obtained in the same extract (4.93 ± 0.37 µg/mg extract), whereas the greater tyrosol content (0.23 ± 0.012 µg/mg extract) was found in Arbequina extract. These results were correlated with the greatest radical scavenging and the highest inhibition of lipoperoxidation process observed in Barnea extract (IC₅₀ of 27.9 ± 1.04 µg/mL; IC₅₀ 22.8 ± 3.5 µg/mL, respectively). In spite of differences, alperujo extracts exhibited notable antioxidant capacities.     

ANTIFUNGAL,AFLATOXIN INHIBITORY AND FREE RADICAL‐SCAVENGING ACTIVITIES OF SOME MEDICINAL PLANTS EXTRACTS

ABSTRACT

The antifungal, aflatoxin inhibitory and antioxidant activity of methanol–aqueous extract (2:1) of 62 medicinal plants was explored. Based on the antifungal results, the extracts of 25 plants showed more than 50% antifungal activity and were further investigated for their aflatoxin inhibition and antioxidant properties. Methanol–aqueous extracts of Phyllanthus emblica and Terminalia chebula fruits caused 100% inhibition of aflatoxin production by the toxigenic strain of Aspergillus flavus in semisynthetic medium at 1 mg/mL. In addition, P. emblica (IC₅₀ = 4.1 µg/mL) and T. chebula (IC₅₀ = 6.9 µg/mL) fruits extracts exhibited strong antioxidant activity during the 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging assay in comparison with butylated hydroxytoluene (IC₅₀ = 8.1 µg/mL) and butylated hydroxyanisole (IC₅₀ = 6 µg/mL).

PRACTICAL APPLICATIONS

Based on the results of the present study, methanol–aqueous extracts of Phyllanthus emblica and Terminalia chebula, being endowed with strong antifungal, aflatoxin inhibitory and antioxidant activity, may be recommended as plant‐based preservatives for the enhancement of shelf life of food items and their protection from the undesirable harmful effects of molds, aflatoxin and free radical‐mediated damages.     

Antioxidant and Antihemolytic Activities of Ethanolic Extract of Flowers,Leaves, and Stems of Hyssopus officinalis L. Var. angustifolius

In this study, antioxidant and antihemolytic activities of ethanolic extract of flowers, leaves, and stems of Hyssopus officinalis L. Var. angustifolius were investigated employing different in vitro assay systems. Extracts showed good antioxidant activity. IC₅₀ for 1,1-diphenyl-2-picryl hydrazyl radical-scavenging activity were 148.8 ± 4.31 μg mL^?1 for flowers, 79.9 ± 2.63 μg mL^?1 for stems, and 208.2 ± 6.45 μg mL^?1 for leaves. All extracts showed moderate iron (II) chelating ability. Extracts exhibited good antioxidant activity in the hemoglobin-induced linoleic acid model and also they were capable of scavenging hydrogen peroxide in a concentration dependent manner. Extracts showed good antihemolytic activity againts hydrogen peroxide-induced hemolysis (IC₅₀ were 48.51 ± 2.27 μg mL^?1 for flowers, 19.47 ± 0.73 μg mL^?1 for leaves, and 63.1 ± 2.65 μg mL^?1 for stems). The total amount of phenolic compounds in the extracts was determined as gallic acid equivalents and total flavonoid content was calculated as quercetin equivalents from a calibration curve.     

Effect of Different Drying Treatments and Solvent Ratios on Phytochemical Constituents of Ipomoea aquatica and Correlation with α-Glucosidase Inhibitory Activity

Ipomoea aquatica is an aquatic plant that is widely consumed in Southeast Asia as a vegetable. In this study, the influence of various ethanol ratios (0, 20, 50, 80, and 100%) as an extraction solvent and different drying methods including air drying, sun drying, and oven drying on phytochemical constituents of I. aquatica was investigated using a proton nuclear magnetic resonance-based metabolomics approach. The effect on α-glucosidase inhibitory activity and total phenolic content was also examined. Clear discrimination was observed between different ethanol ratios and different drying processes by principal component analysis. The highest α-glucosidase inhibitory activity was observed for absolute ethanol extract from the oven drying method with IC₅₀ value of 204.0 ± 59.0 µg/mL and total phenolic content value of 22.0 ± 0.7 µg gallic acid equivalent/mg extract. Correlation between the α-glucosidase inhibitory activity and the metabolite were analyzed using a partial least square analysis. The metabolites that are responsible for the activity were quercetin derivatives, chlorogenic acid derivatives, sucrose, and fructose. This study highlights the basis for future investigations of I. aquatica as a source of food that has the potential for nutraceutical enhancement and as ingredient in medicinal preparation.     

In Vitro Potential of Ascophyllum nodosum Phenolic Antioxidant-Mediated α-Glucosidase and α-Amylase Inhibition

ABSTRACT: Ascophyllum nodosum is a brown seaweed that grows abundantly in the Northeast coastal region. In this study, the potential of A. nodosum for type 2 diabetes management through antioxidant-mediated α-glucosidase and α-amylase inhibition was investigated. After the initial screening of 4 locally harvested seaweeds, A. nodosum was chosen for its highest phenolic content and was subjected to water extraction. Among extraction ratios of 50 g to 100 to 1000 mL at room temperature, 50 g/400 mL yielded the highest phenolic content of 4.5 mg/g wet weight. For evaluation of extraction temperature ranging from 20 to 80 °C, 50 g/400 mL was chosen as a minimum amount of extractant. Among temperatures studied, extraction at 80 °C resulted in the highest total phenolic contents (4.2 mg/g wet weight). All extracts had similar levels of antioxidant activity in the range of 60% to 70% in terms of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The 80 °C extract had the highest α-glucosidase and α-amylase inhibitory activity with IC₅₀ of 0.24 and 1.34 μg phenolics, respectively, compared to the IC₅₀ of acarbose, reference inhibitor, being 0.37 and 0.68 μg. The results show that fresh A. nodosum has strong α-glucosidase and mild α-amylase inhibitory activities that correlated with phenolic contents. This study suggests a nutraceutical potential of A. nodosum based on phytochemical antioxidant and antihyperglycemia activities.     

Metabolite profiling and inhibitory properties of leaf extracts of Ficus benjamina towards α-glucosidase and α-amylase

The use of antioxidant-rich medicinal plants having the potential to reduce oxidative stress and postprandial hyperglycemic pressure is one of the most promising option for the management of diabetes. This study presents information on metabolite profiling and in vitro anti-diabetic effects of leaf extracts of Ficus benjamina. The DPPH (2, 2-diphenyl-1-picrylhydrazyl radicals) assay was performed to determine the in vitro antioxidant potential of the plant extracts. The anti-diabetic effects were investigated by evaluating inhibitory properties of F. benjamina leaf extracts towards carbohydrate hydrolyzing enzymes, i.e., α-glucosidase and α-amylase, whereas ¹H NMR and UHPLC-QTOF-MS/MS analytical methods were employed for metabolite profiling of F. benjamina leaf extracts. Among 40, 60, 80, and 100% ethanolic leaf extracts of F. benjamina, 80% ethanolic extract exhibited the highest antioxidant activity based upon its DPPH radical scavenging ability (IC₅₀ value: 63.71 ± 2.66 µg/mL). The 80% ethanolic leaf extract of F. benjamina also proved to be the most efficient α-glucosidase and α-amylase inhibitor with IC₅₀ values of 9.65 ± 1.04 µg/mL and 13.08 ± 1.06 µg/mL, respectively; these values were even better than acarbose with α-glucosidase inhibition activity (IC₅₀ = 116.01 ± 3.83 µg/mL) and α-amylase inhibition activity (IC₅₀ = 152.66 ± 7.32 µg/mL). Moreover, a total of 31 metabolites were identified in F. benjamina leaf extract, which may have the potential to contribute to its antioxidant and inhibitory properties against carbohydrate hydrolyzing enzymes. The findings of this study depict F. benjamina leaf extracts as a promising α-glucosidase and α-amylase inhibitor, and therefore, can be utilized for the development of anti-diabetic functional diets/nutra-pharmaceuticals.     

Assessment of phenolic profile of Turkish honeys

In this study, phenolic profile and antioxidant activity of 60 Turkish honey samples of nineteen different floral origins were evaluated by ultra-performance liquid chromatography with electrospray ionization coupled to tandem mass spectrometry, providing the identification of 32 phenolic compounds. Thyme (1051.58 mg/kg), pine (994.18 mg/kg), carob (935.03 mg/kg), eucalyptus (814.46 mg/kg), rhododendron (680.71 mg/kg), heather (562.59 mg/kg), cedar (561.83 mg/kg), and euphorbia (501.64 mg/kg) present significantly high phenolic content. Moreover ferulic, homogentisic, gentisic, syringic, 3,4-dihydroxybenzoic, caffeic, vanillic, p-coumaric, 4-hydroxy benzoic, and trans-2-hydroxy cinnamic acids were the most abundant of the determined compounds. The antioxidant activities of the honeys were evaluated by β-carotene-linoleic acid inhibition, DPPH free radical scavenging activity and ABTS⁺ cation radical scavenging activity which were measured as IC₅₀: 10.87 – 48.23 µg/mL, SC₅₀: 54.33 – 99.40 µg/mL and SC₅₀: 10.33 – 41.20 µg/mL, respectively. Phenolic compounds are considered antioxidant constituents, and they could be stated as components that account for antioxidant activity in Turkish honeys.     

Zingiber officinale extract exhibits antidiabetic potential via modulating glucose uptake, protein glycation and inhibiting adipocyte differentiation: an in vitro study

BACKGROUND: Ginger, the rhizome of Zingiber officinale Roscoe (Zingiberaceae), a perennial herbaceous plant is native to Southern Asia. Study was aimed to evaluate antioxidant and antidiabetic potential of ginger extract and its characterization. Possible mode of action to elicit antidiabetic activity was also evaluated. METHODS AND RESULTS: Ethyl acetate extract of ginger (EAG) was evaluated for its antioxidant activity in terms of DPPH radical scavenging potential with an IC₅₀ value of 4.59 µg/ml. Antidiabetic activity of EAG was evaluated by estimating antiglycation potential (IC₅₀ 290.84 µg/ml). HPLC profiling of EAG revealed the presence of phenolic components, gingerol and shoagol as major constituents. After determining sub‐toxic concentration of EAG (50 µg/ml), efficacy of extract to enhance glucose uptake in cell lines were checked in L6 mouse myoblast and myotubes. EAG was effective at 5 µg/ml concentration in both cases. Antibody based studies in treated cells revealed the effect of EAG in expressing Glut 4 in cell surface membrane compared to control. CONCLUSION: The antidiabetic effect of ginger was experimentally proved in the study and has concluded that the activity is initiated by antioxidant, antiglycation and potential to express or transport Glut4 receptors from internal vesicles. Copyright © 2012 Society of Chemical Industry     

Effects of protein hydrolysate from chicken feather meal on tyrosinase activity and melanin formation in B16F10 murine melanoma cells

Tyrosinase is a copper-containing enzyme that controls mammalian melanogenesis. Tyrosinase inhibitors are important for their potential application in cosmetic products. Chicken feather meal is a rich source of amino acids, which have been linked with tyrosinase inhibition activity. This study investigated the tyrosinase inhibitory properties of protein hydrolysates prepared from chicken feather meal. Protein hydrolysates prepared by pepsin-pancreatin with MW <3 kDa exhibited strong tyrosinase inhibition activity for both monophenolase (IC₅₀ 5.780 ± 0.188 µg/mL) and diphenolase activities (IC₅₀ 0.040 ± 0.024 µg/mL) in a cell-free mushroom tyrosinase system. These samples were uncompetitive inhibitors with Ki values of 18.149 and 27.189 µg/mL in monophenolase and diphenolase activities, respectively. A cell culture model showed that this hydrolysate had the strongest inhibition on the viability of B16F10 cells (IC₅₀ 1.124 ± 0.288 µg/mL) and 0.210 µg/mL of the sample exhibited inhibition of tyrosinase activity by 50.493% and melanin synthesis by 14.680% compared to the control.     

Antioxidant activities and inhibitory effects of dietary plants against sodium nitroprusside induced lipid peroxidation in the mouse brain and liver

The antioxidant properties of aqueous extracts of 6 medicinal plants, Phyllanthus emblica, Terminalia chebula (black and yellow), Terminalia arjuna, Balsamodendron Mukul, and Alium sativum against lipid peroxidation in mouse tissues were investigated. Extracts showed inhibition against thiobarbituric acid reactive species (TBARS) induced by pro-oxidant (5 μM sodium nitroprusside) in the mouse brain and liver. Extracts displayed high free radical scavenging activities against DPPH (IC₅₀, 23.23±1.2 μg/mL, P. emblica), 20.24±0.9 μg/mL (T. chebula yellow), 17.33±1.1 μg/mL (T. chebula black), 19.44±0.45 μg/mL (T. arjuna), 56.59±2.1 μg/mL (Balsamo-dendron Mukul), and higher than 200 μg/mL (A. sativum). Higher antioxidant and inhibitory effects of T. chebula black are attributed to a higher phenolic content, Fe(II) chelating ability, reducing ability, nitric oxide radical scavenging, and free radical scavenging activity. Oxidative stress in the brain and liver could potentially be managed/prevented by dietary intake of these plants.     

An exploration of angiotensin-converting enzyme (ACE) inhibitory peptides derived from gastrointestinal protease hydrolysate of milk using a modified bioassay-guided fractionation approach coupled with in silico analysis

An improved bioassay-guided fractionation was performed to effectively screen angiotensin-I converting enzyme inhibitory (ACEI) peptides from milk protein hydrolysate. The aqueous normal phase liquid chromatography, namely hydrophilic interaction liquid chromatography (HILIC), was used as a format of solid-phase extraction (SPE) short column for the first fractionation, then the HILIC-SPE fraction with the best ACEI activity (IC₅₀ = 61.75 ± 5.74 µg/mL; IC₅₀ = half-maximal inhibitory concentration) was obtained when eluted by 95% acetonitrile + 0.1% formic acid (fraction F1). The best HILIC-SPE fraction was further fractionated using reversed-phase (RP)-SPE short column. The best RP-SPE fraction was obtained when eluted by 20% acetonitrile + 0.1% formic acid (fraction P3) with an ACEI activity of IC₅₀ 36.22 ± 1.18 µg/mL. After the 2-step fractionation, the IC₅₀ value of fraction P3 significantly decreased by 8.92-fold when compared with the crude hydrolysate. Several peptides were identified from fraction P3 using liquid chromatography-tandem mass spectrometry. The in silico analysis of these identified sequences based on the BIOPEP database predicted that HLPLPLL (HL-7) was the most active peptide against angiotensin-converting enzyme (ACE). The HL-7 derived from β-casein showed a potent ACEI activity (IC₅₀ value is 16.87 ± 0.3 µM). The contents of HL-7 in the gastrointestinal protease hydrolysate and RP-SPE fraction originated from 1 mg of milk proteins were quantified using a multiple reaction monitoring mode upon liquid chromatography-tandem mass spectrometry analysis to give 19.86 ± 1.14 pg and 14,545.8 ± 572.9 pg, respectively. Besides, the kinetic study indicated that HL-7 was a competitive inhibitor and the result was rationalized using the docking simulation. The study demonstrated an efficient screening of ACEI peptides from commercially available milk powders using a simple SPE process instead of a sophisticated instrument such as HPLC. Moreover, the potent ACEI peptide HL-7 uncovered by this method could be a natural ACE inhibitor.     

Essential oil composition,total phenolic content,antioxidant and antibiofilm activities of four Origanum species from southeastern Turkey

This study reports a comparative screening of four species of Origanum in Turkey, based on their essential oil composition, total phenolic content, antioxidant and antibiofilm activities. The major components of essential oils were p-cymene, linalool, and thymol. The total phenolic contents differed from 3.81 to 47.54 mg of GAE/g of extract. The concentrations of flavonoids varied from 12.74 to 58.39 mg of Ru/g of extract. Antioxidant activity was determined in vitro using DPPH reagent and expressed as concentration of each extract required to inhibit radical by 50% (IC₅₀) values that ranged from 16.03 to 48.94 μg/ml. Our results indicated that chloroform extracts of species O. majorana and O. onites, with a total content of polyphenols (47.54 mg of GAE/g and 45.17 mg of GAE/g, respectively) and an IC₅₀ of 16.03 μg/ml and 16.89 μg/ml, respectively were more antioxidant. Among the essential oil concentrations tested, maximum antibiofilm activity was found as 92.24% against M. luteus NRRL-B 1013 by O. majorana essential oil at 50 mg/ml.     

Development of enzyme-linked immunosorbent assays for Sudan dyes in chilli powder,ketchup and egg yolk

This study aimed at developing sensitive competitive enzyme-linked immunosorbent assays (ELISAs) for the banned Sudan dyes using polyclonal antibodies. Three different formats were developed and characterized in terms of sensitivity, selectivity and rapidity. A competitive indirect ELISA was developed, which showed an IC₅₀ of 3.8 µg l^–1. Two competitive direct ELISAs were also developed, in which the antibody was added before or simultaneously with the other reagents; the first showed an IC₅₀ of 8.3 µg l^–1 and the latter showed an IC₅₀ of 4.9 µg l^–1. Nevertheless, considering dilution of extracts which is needed to offset matrix interference, the limits of detection of the three formats were substantially the same (10 µg kg^–1). The antibodies in all three test formats were able to recognize Sudan I and partially Sudan II, III and IV; no cross-reactivity was observed with the five edible dyes. Twenty food samples, including chilli powder, paprika, ketchup, and egg, were extracted by a simple sample preparation and very limited dilution. Extracts were analyzed by the developed competitive direct ELISA with the simultaneous addition of reagents. A good correlation was observed (y = 1.19x–10.0, r ² = 0.991, n = 20) when the data was compared with that obtained through a conventional HPLC method.     

Phenolic compounds and the biological effects of Pu-erh teas with long-term storage

Pu-erh tea has gained more and more popularity and attracted much attention for its various biological effects. The objective of this study was to determine the active phenolic compounds and the biological effects of 15 differently aged Pu-erh teas. The results showed that 43 active phenolics, containing 7 flavan-3-ols, 11 organic acids, and esters, 3 proanthocyanidin dimers, 2 benzotropolones, and 20 flavonoid glycosides were identified based on high-performance liquid chromatography coupled to electrospray ionisation and quadrupole time-of-flight tandem mass spectrometry (HPLC-ESI-QTOF-MS/MS). In particular, 2’-O-galloylhyperin and quercetin-3-O-p-coumaroyl-rhamnosyl-arabinosyl-hexoside were identified from constituents of tea for the first time. The 15 Pu-erh teas exhibited strong DPPH and ABTS scavenging activity in a concentration-dependent manner with IC₅₀ 0.99–2.12 and 0.97–2.67 mmol Trolox equivalent antioxidant capacity/g, respectively. All of the Pu-erh teas tested significantly inhibited the proliferation of SMMC-7721 cells, in a dosage-dependent manner. Of the 15 Pu-erh teas examined, the cake tea P6 had the strongest effect on SMMC-7721 cells with IC₅₀ = 65.88 ± 3.53 µg/mL. The others Pu-erh teas had an IC₅₀ = 96 – 509 µg/mL. Our results also indicated that not all the older Pu-erh teas display stronger anti-activities and anti-cancer than the younger ones and the youngest Pu-erh tea did not possess the highest level of active components. This study provides useful information for consumers to deeply understand the chemical constituents and bioactivity of Pu-erh tea preserved for a long time.     

Antioxidant, antimicrobial, and anticancer activity of 3 Umbilicaria species

Abstract: The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 28.45 to 97.82 μg/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents.     

Comparative study of the essential oil composition of Salvia urmiensis and its enzyme inhibitory activities linked to diabetes mellitus and Alzheimer’s disease

The genus Salvia has economic importance due to its broad uses in traditional medicine, perfume, food, and pharmaceutical industries. In the present work, various extracts and essential oils of Salvia urmiensis Bunge., were screened for their inhibitory activity against acetylcholinesterase and butyrylcholinesterase, the enzymes linked to neurodegeneration, and against α-amylase and α-glucosidase (involved in diabetes mellitus; DM). Chemical compositions of the essential oils of leaves and flowers of the plant were also determined. The tested samples exhibited moderate to high anti-diabetic potential (IC₅₀ = 8–145 µg/mL) and moderate anticholinesterase activity (IC₅₀ = 44–892 µg/mL). Essential oil of leaves was rich in ester compounds such as ethyl linoleate (19%), methyl hexadecanoate (17%), and methyl linoleate (7.5%). The major compound of essential oil of flowers was 6,10,14-trimethyl-2-pentadecanone (55.7%). This is the first report on the enzyme inhibitory activity of S. urmiensis and also the chemical composition of its leaves and flowers in essential oils. The results indicated that S. urmiensis could be considered a valuable source for functional foods and pharmaceuticals.     

Phenolic compounds’ characterization of Artemisia rutifolia spreng from Pakistani flora and their relationships with antioxidant and antimicrobial attributes

Artemisia rutifolia (Asteraceae) had been used in traditional medicines for the treatment of different ailments. In the current study, an effort was made to explore the phenolic composition, antioxidant, and antimicrobial activities of different solvent extracts obtained from A. rutifolia leaves. The reverse-phase high-performance liquid chromatographic (RP-HPLC) analysis revealed the higher extent of polyphenolic compounds (i.e., gallic acid, caffeic acid, chlorogenic acid, syringic acid, sinapic acid, p-coumaric acid, m-coumaric acid, ferulic acid, vanillic acid, myricetin, and quercetin) in methanol extract. Methanol extract consistently showed the highest total phenolic contents (98 ± 2 µg GAE/mg of plant extract), total flavonoid contents (28 ± 0.0 µg QE/mg of plant extract), antimicrobial activity, free radical (DPPH) scavenging (IC₅₀ = 39 µg/mL) activity, and reducing power (18.3 ± 0.2 mg GAE/g of plant extract) followed by those of chloroform and hexane extracts, respectively. The current study concluded that extracts of A. rutifolia are novel natural source of antioxidative and antimicrobial agents for the treatment of oxidative stress-related disorders and microbial infections.     

Nutrient Compositions,Antioxidant Activity,and Common Phenolics of Sonneratia apetala (Buch.-Ham.) Fruit

Fruits of Sonneratia apetala (Buch.-Ham.) are widely used as food and in treating various diseases in the tropical coastal areas. This study evaluated nutrient compositions in the pericarp and seed of this fruit. Each pericarp and seed was successively fractionated into n-hexane, diethyl ether, chloroform, ethyl acetate, and methanol. Polyphenols contents and antioxidant activities of different pericarp and seed fractions were measured in different in vitro methods and phenolic compounds were determined by HPLC. Carbohydrates, proteins, lipids, and ash contents were 29.6, 8.8, 2.8, and 25.5% of dry weight in pericarp, whereas 28.3, 11.5, 4.2, and 22.7% in seed, respectively. Among the mineral macro-elements, K content was the highest followed by Na, Ca, Mg, P, and S while in micro-elements, Fe was at the largest followed by Mn, Zn, and Cu. The methanol fraction of seed showed the highest polyphenols content (221.9 mg gallic acid equivalent/g fraction), 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀ = 2.1 μg/mL) and NO (IC₅₀ = 490.8 μg/mL) free radical scavenging. Similarly, methanol fraction of seed also attained very strong reducing power (OD = 1.67 at 100 µg/mL), Fe²⁺ chelating and total antioxidant capacity. When subjected to high-performance liquid chromatogram analysis, six polyphenols namely caffeic acid, (+)-catechin, (-)-epicatechin, ellagic acid, gallic acid, and quercetin were detected and quantified as 88.1, 1459.3, 310.1, 616.9, 416.7, and 71.8 mg/100 g of methanol fraction of seed, respectively. Therefore, the fruit of S. apetala, especially its seeds could be of great use in preparation of functional foods and dietary supplements.     

Structural features,antioxidant and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars

In this study the structural features, antioxidant, and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars, namely Huangjingui and Qilan, were investigated. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thiolysis-high performance liquid chromatography-electrospray ionization mass spectrometry analyses confirmed that these proanthocyanidins were built up a mixture of procyanidins, propelargonidins, and prodelphinidins, with the predominance of procyanidins. The proanthocyanidins in leaves of Huangjingui and Qilan cultivars exhibited potent antioxidant activities with IC₅₀ values of 87.36 ± 0.83 and 97.33 ± 0.61 µg/mL in 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, 43.57 ± 0.25 and 55.01 ± 0.22 µg/mL in 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay, and with ferric reducing antioxidant power values of 4.83 ± 0.03 and 3.97 ± 0.02 mmol ascorbic acid equivalent/g in ferric reducing antioxidant power assay. It was also found that these proanthocyanidins had strong inhibition on tyrosinase activity with IC₅₀ values of 54.8 ± 1.27 and 20.0 ± 0.89 µg/mL for Huangjingui and Qilan cultivars, respectively. The results indicated that the proanthocyanidins in leaves of two tea cultivars could be considered as natural antioxidants and tyrosinase inhibitors applied in pharmaceutical and cosmetic industries in the future.     

Cladonia lichens and their major metabolites as possible natural antioxidant,antimicrobial and anticancer agents

The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activities of the acetone extracts of the lichens Cladonia furcata, Cladonia pyxidata and Cladonia rangiferina and their atranorin and fumarprotocetraric acid constituents. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power, and determination of total phenolic and flavonoid compounds. As a result of the study atranorin had largest free radical scavenging activity with IC₅₀ values 131.48 μg/mL. Moreover, the tested samples had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was fumarprotocetraric acid with minimum inhibitory concentration values ranging from 0.031 to 0.125 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All samples were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 10.97 to 41.23 μg/mL.