Characterization Of Phenolic Compounds Research Articles

Identification and determination of bioactive phenylpropanoid glycosides of Aloysia polystachya (Griseb. et Moldenke) by HPLC-MS

Aloysia polystachya (Griseb. et Moldenke) has not been deeply investigated in past years and currently data about its chemical composition are limited. Phenolic compounds characterization can be very difficult in vegetable matrices, owing to bonds to sugar moieties or conjugation, giving rise to complex structures. In this work, methanolic extracts of Aloysia polystachya leaves were analyzed by HPLC-ESI-MS, the favourite technique for the separation and quantification of their polyphenols. To assess the complete characterization and quantification of the phenylpropanoid fraction, three different MS techniques have been coupled to HPLC: ion trap mass spectrometry (Ion Trap LC/MS), quadrupole-time of flight high resolution mass spectrometry (Q-TOF HRMS) and triple-quadrupole (TQ LC/MS) for the quantification. Eleven phenylpropanoid glycosides were identified and quantified and, among them, the compounds forsythoside A, plantainoside C, purpureaside D, martynoside and its two isomers were detected for the first time to the best of our knowledge. The results presented here could be helpful to assess the quality of this plant and could further contribute to the chemotaxonomy of the genus.

Effect of Phoenix dactylifera L. Sap Against Bleomycin-Induced Pulmonary Fibrosis and Oxidative Stress in Rats: Phytochemical and Therapeutic Assessment

Lung fibrosis is a lethal interstitial disease characterized by massive proliferation of fibroblast inducing excessive collagen deposition. We aimed to investigate whether Date palm sap (DPS) can play a protective effect on bleomycin (BLM)-induced lung fibrosis in rats. MaleWistar rats were given single dose of BLM (4 mg/kg, intra-tracheal), while DPS (45 mg/kg, intraperitoneal) was administered three days later and continued for three weeks (BLM/DPS group). Characterization of phenolic compounds in DPS was evaluated by LC-HRESIMS analysis. Hematoxylin-eosin and Masson’s Trichome staining were used for the revelation of lung architecture, collagen deposition, and fibrosis score. Antioxidant effects of DPS and hydroxyproline content in lung tissues were studied using standard spectrophotometric methods. We reveled by liquid chromatography-high-resolution electrospray ionization mass spectrometry (LC-HRESIMS) an important amount of vitamins and phenolic compounds in DPS. BLM increased lipid peroxidation (MDA) and superoxide dismutase (SOD) levels and decreased catalase (CAT) activity. BLM also induced inflammation and accumulation of bundles of collagen in lung. DPS treatment normalized MDA, SOD, and CAT levels, decreased hydroxyproline level and morphological lesions induced by BLM. In conclusion, DPS has a protective effect against BLM-induced murine lung fibrosis due to its richness in phenolic compounds and vitamins.

Characterization of phenolic compounds from Phyllanthus emblica fruits using HPLC-ESI-TOF-MS as affected by an optimized microwave-assisted extraction

ABSTRACT A simple microwave-assisted method for extracting antioxidant phenolic compounds from emblic (Phyllanthus emblica L.) fruits was developed and optimized with response surface methodology (RSM). The influence of process conditions including microwave power, irradiation time, ethanol concentration, and solvent-to-solid ratio on the extraction of total phenolic content was analyzed by using a second-order regression equation. The optimum extraction parameters were as follows: microwave power, 480 W; irradiation time, 29 s; ethanol concentration, 66%; liquid-to-solid ratio, 25 mL/g. Under these conditions, the recovery of total phenolic content was 133.58 ± 15.61 mg gallic acid equivalent/g dry weight (DW). The extracts were also analyzed using HPLC-ESI-TOF-MS to identify eight compounds including hamamelitannin, mucic acid-1,4-lactone-3-O-gallate, ellagic acid, and isocorilagin. To our knowledge, this is the first report of hamamelitannin in emblic fruit. The extracts exhibited strong antioxidant capacities in DPPH and ABTS+ radical scavenging assays and showed an excellent inhibition of lipid peroxidation and reducing property. These findings illustrated that the optimized microwave-assisted extraction method was efficient in extracting phenolic compounds with high antioxidant activity from emblic fruits. It was suggested that emblic fruits may be a new potential source as natural antioxidant agents applied in food industry.

Optimized Extraction by Response Surface Methodology Used for the Characterization and Quantification of Phenolic Compounds in Whole Red Grapes (Vitis vinifera).

Scientific research has focused on the characterization of bioactive polyphenols from grape seeds and skins, and the pulp has often been overlooked. However, since the beneficial properties of grapes are associated with the consumption of whole fruit, a full extraction and posterior characterization of the phenolic compounds in whole grapes is required to identify the involved bioactive compounds. Such methodologies are not currently available for the whole edible parts of red grapes. This study aimed to determine the best polyphenol extraction conditions of whole red grapes, and apply the method to characterize and quantify the polyphenol composition of three different grapes. The optimized conditions were 80 mL/g, 65% methanol (1% formic acid), 72 °C, and 100 min under agitation of 500 rpm. Also, methanol and ethanol were compared as extraction solvents, and methanol achieved statistically higher extraction rates for anthocyanins. The results of this work suggest a higher quantification of phenolic compounds when red grapes are analyzed whole, including the seeds, pulp, and skin.

Phenolic compounds characterization and antioxidant activities of selected spices from Cameroon

Methanol extracts of five spices from Cameroon were analyzed for their phytochemical composition and antioxidant activities. The Xylopia aethiopica extract with the highest total phenolics and flavonoids contents showed a strongest antioxidant activity compared to tert-butylhydroquinone (TBHQ) using both the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt (ABTS) radicals scavenging assay. The identification and quantification of major phenolics acids and flavonoids was carried out by HPLC-DAD. T-cinnamic acid and ferulic acid was the phenolic acids mainly distributed within the methanolic extracts analyzed. Sinapic acid was identified at low concentration only in Ricinodendron heudelotii. The common flavonoids catechin and epicatechin were detected with highest concentration in Xylopia aethiopica extract. Eugenol was identified at high concentration (125.39–1326.29 μg/g) in all extracts. The results of the present study suggest that the extracts analyzed, particularly Xylopia aethiopica and Aframomum citratum are potential sources of natural antioxidants agents.

Phenolic compounds characterization by LC-DAD- ESI/MSn and bioactive properties of Thymus algeriensis Boiss. & Reut. and Ephedra alata Decne

Scientific research has been focused on finding natural occurring molecules from plant origin. Herein, infusion, decoction and hydroethanolic extracts of Thymus algeriensis Boiss. & Reut. and Ephedra alata Decne. from Algeria were phytochemically characterized by LC-DAD-ESI-MSn, and evaluated regarding bioactive properties (antioxidant and antibacterial). Flavonol and flavone glycoside derivatives and phenolic acids, specially rosmarinic acid and kaempferol-O-glucuronide were the major compounds in T. algeriensis extracts. Otherwise, E. alata presented isoflavones and flavonol derivatives as main compounds, being hydroxypuerarin isomer 1 the major molecule. Aqueous extracts had significantly higher antioxidant activity, being this activity correlated with the amount of phenolic compounds. Antimicrobial activity of the extracts was tested against multi-resistant bacteria strains from clinical isolates. The obtained MIC values indicate that the hydroethanolic extracts revealed the highest effect, especially the one of T. algeriensis against Gram-positive bacteria. Hence, these plant extracts could be used in the development of bioactive ingredients.

Metabolomic approach for characterization of phenolic compounds in different wheat genotypes during grain development.

The phenolic-profiling of seven different wheat (Triticum aestivum) genotypes was investigated for the first time during different stages of grain development (milky, softy, physiological maturity and mature). Free and bound phenolic compounds were extracted separately and analyzed by UPLC-QTOF-MSE. Total phenolic content significantly decreased, up to 50% depending on the genotype, towards the maturation of grain. The highest content (free and bound) was observed in the most immature grains, while the lowest level was found in mature grains (408.0 and 165.0 GAE mg/100 g, respectively). Globally, 237 phenolic compounds were identified, divided into 5 classes: flavonoids (85), phenolic acids (77), other polyphenols (51), lignans (16) and stilbenes (8). UPLC-MS results showed a progressively decrease of the number of phenolic identification (ID) all along grain development, milky (213), softy (192), physiological maturity (169) and mature (144). The proportion bound to free phenolic progressively increased, reaching the maximum at physiological maturity, indicating a possible enzymatic reactions and complexation during grain growth. Ferulic acid, diphyllin, 4-hydroxybenzoic acid, ferulic acid isomer, apigenin 7-O-apiosyl-glucoside isomer and myricetin isomer were the most abundant compounds. Chemometric tools showed a clear separation between immature and mature grain for all genotypes. Phenolic profile varied significantly among genotypes, this result can help the selection of varieties towards a higher retention of bioactive compounds. Noteworthy, immature wheat grains can be considered a rich source of phenolic compounds and as an attractive ingredient to incorporate to functional foods.

Characterization of phenolic compounds and antioxidant activity in sorghum grains

Phenolic composition and relative antioxidant activity were investigated in six varieties of sorghum including pigmented and non-pigmented pericarp varieties. Whole grain sorghum extracts were subjected to acidified acetone extraction and were analysed using UHPLC with an attached online ABTS system and Q-TOF LC/MS. Results showed that the black pericarp variety Shawaya short black 1 and the brown pericarp variety IS11316 had the highest total phenolic content (TPC) and total proanthocyanidin content (TPAC), consequently resulting in overall high antioxidant activity. The phenolic compounds that had the highest antioxidant activity in Shawaya and IS11316 were catechin, 1-O-cafferolglycerol-O-glucoside, taxifolin and pentahydroxyflavanone-(3->4)-catechin-7-O-glucoside. Furthermore, comparison of the phenolic profiles has shown that the varieties with higher antioxidant activity generally had higher quantities and more diverse range of polyphenols. Thus, this study indicates that there is no independent compound in sorghum that results in its high antioxidant activity but rather it is the cumulative effect of various phenolic compounds.

Phenolic composition of tomato varieties and an industrial tomato by-product: free, conjugated and bound phenolics and antioxidant activity

The aim of this study was to isolate, identify and quantify soluble free phenolics, conjugated acid-hydrolysable phenolics (AHP) and alkaline-hydrolysable phenolics, and bound phenolics (BP) fractions from two tomato varieties (saladette and grape) and an industrial tomato by-product, as well as, to determine their antioxidant capacity. Phenolic composition was determined using Folin-Ciocalteu's method and HPLC-DAD. AHP were predominant in grape and saladette tomato extracts (91.47 ± 17.28mg gallic acid equivalents (GAE) per g dry extract (DE) and 57.41 ± 8.80mg GAE per g DE, respectively), while BP form was predominant in tomato by-product (51.30 ± 10.91 GAE per g DE). AHP extract of grape tomato presented the highest antioxidant capacity by DPPH assay (252.35 ± 42.55 μmol trolox equiv (TE) per g DE). In the case of ORAC assay, AHP fractions from both grape (1005.19 ± 138.52μmol TE per g DE) and saladette tomatoes (804.16 ± 131.45μmol TE per g DE), and BP fraction from by-product (852.40 ± 71.46μmol TE per g DE) showed the highest ORAC values. Caffeic acid was the most abundant phenolic acid and it was found mainly in its conjugated forms. Naringenin was the most abundant flavonoid and it was mainly detected in bound form. Our analysis allowed a better characterization of phenolic compounds in whole tomato and by-product, remarking the importance of the fractionation. The valorization of the industrial tomato by-product, through the use of its different fractions of phenolic antioxidant compounds, could generate additional income to the tomato industry and reduce the waste disposal problem.

Optimization of microwave‐assisted extraction parameters and characterization of phenolic compounds in Yellow European Plums

Yellow European Plums (YEPs) are a rich source of phenolic compounds and antioxidants, which can be obtained using microwave‐assisted extraction (MAE). During this study, two MAE experiments were performed to optimize MAE extraction parameters and the MAE process using YEPs. The first experiment was to determine the influence of independent variables such as solvent concentration (20, 60, and 100 %) and solid‐to‐solvent ratio (0.05, 0.1, and 0.15 g/mL), on the yield of total phenolic content (TPC) and antioxidant activity (1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP)), for ethanol and methanol, during MAE. Using a response surface methodology, the optimized extraction parameters for MAE were then found to be 60 % ethanol at a solid‐to‐solvent ratio of 0.1 g/mL. Using the optimized parameters from the first experiment, the second experiment evaluated the effect of microwave temperature (50, 60, 70 °C) and duration (5, 10, and 15 min) on TPC, DPPH, and FRAP, using a face‐centered central composite design. Individual phenolic compounds, including ascorbic acid, neochlorogenic acid, and chlorogenic acid, were quantified using high performance liquid chromatography. In the second experiment, it was observed that time and temperature had a significant (p ≤ 0.05) effect on the extraction of phenolic compounds from four genotypes of YEPs. However, due to their diverse phenolic composition, there was not one optimal operating time and temperature suitable for all genotypes.

Characterisation of phenolic compounds by UPLC-QTOF-MS/MS of geopropolis from the stingless bee Melipona subnitida (jandaíra).

Melipona subnitida Ducke (jandaíra) is a stingless bee native to north-eastern Brazil, which produces geopropolis, a mixture of beeswax, plant resins, pollens and earth that is used for sealing beehives. To extend the knowledge on phenolic compounds in fractions obtained by C18-solid phase extraction (SPE) of nine geopropolis samples from Melipona subnitida collected at different times. Chromatographic profiles of nine samples of geopropolis from jandaíra were analysed by ultra-performance liquid chromatography coupled with a diode array detector and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF-MS/MS) and combined with the use of data-independent acquisition (MSE) for the profiling and structural characterisation of the phenolic compounds. The isolated compound was identified by nuclear magnetic resonance of hydrogen and carbon (1 H- and 13 C-NMR). The present study with geopropolis of jandaíra resulted in the characterisation of 51 phenolics by UPLC-DAD-QTOF-MS/MS: four galloyl glucosides, one ellagic acid, 11 acyl-hexosides, 23 acyl-galloyl-hexosides and 12 flavonoids. The structures of two compounds (1,6-di-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside and 1-O-cinnamoyl-6-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside) were established by 1 H and the attached proton test (APT) experiments as well as high-resolution electrospray ionisation mass spectroscopy (HR-ESI-MS) analysis. The geopropolis of jandaíra showed phenolic compounds galloyl hexosides, ellagic acid, acyl-(cinnamoyl/coumaroyl)-hexosides, acyl-(cinnamoyl/coumaroyl)-galloyl-hexosides and flavonoids (aglycones and acylated-O-glycosides).

The LC-MS/MS characterization of phenolic compounds in leaves allows classifying olive cultivars grown in South Tunisia

Olive (Olea europaea L.) is one of the most important fruit species in the Mediterranean basin, where 95% of the world's olive orchards are planted, and has become an economically valuable crop worldwide due to an increasing demand in olive oil for human consumption. The aim of the present research was to classify Tunisian olive cultivars based on their phenolic profile and to test the potentiality of chemometrics as a tool for cultivars discrimination. The phenolic compounds present in 21 samples of olive leaves, collected during the normal picking period for olive oil production in South Tunisia, were analysed by liquid chromatography mass spectrometry. Models based on principal component analysis (PCA) and hierarchical cluster analysis (HCA) was used for discrimination purposes as a function of the tree varieties and cultivation zone.Qualitative and quantitative compositional analysis revealed 12 major phenolic compounds among which oleuropein (110.38–4741.62 mg/kg), hydroxytyrosol (5.40–290.19 mg/kg), apigenin 7-O-glucoside (9.44–2475.53 mg/kg), tyrosol (2.10–174.62 mg/kg), catechin (0–37.60 mg/kg) and vanillic acid (3.23–256.57 mg/kg) were identified. Oleuropein showed the highest amount in Fougi cultivar (4741.62 mg/kg), whereas the lowest level was registered in Zarrazi injassi cultivar (110.38 mg/kg). However, Zalmati Zarzis exhibited high concentrations of tyrosol, vanillic and caffeic acid, and vanillin. In general, rutin and luteolin 7-O-glucoside were the two main flavonoids detected. Dendrogram analysis revealed three main clusters, further confirmed through PCA.

Characterization of phenolic compounds in mature Moroccan Medjool date palm fruits (Phoenix dactylifera) by HPLC-DAD-ESI-MS

The purpose of this study was to determine the phytochemical composition of the rarely studied mature Moroccan Medjool dates (Phoenix dactylifera). The amount of total phenolic compounds, determined by analytical high performance liquid chromatography (HPLC) in combined 2% aqueous acetic acid and methanol extracts was 61.3 mg/100 g wet weight. The phenolic compounds, definitively identified by high performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry (HPLC-DAD-ESI-MS) were (I) chelidonic acid, (II) 3, 4-dihydroxybenzoic acid, (III) dicaffeoyl shikimik acid isomer-1, (IV)p-hydroxybenzoic acid, (V) caffeic acid glucoside, (VI) ferulic acid diglucoside, (VII) dicaffeoyl shikimik acid isomer-2, (VIII) vanillic acid, (IX) dicaffeoyl shikimik acid isomer-3, (X)p-hydroxybenzaldehyde, (XI) caffeoyl shikimik acid-1, (XII) caffeoyl shikimik acid-2, (XIII) caffeoyl shikimik acid-3, (XIV) vanillin, (XV)p-coumaric acid, (XVI)trans-ferulic acid, (XVII)cis-ferulic acid, (XVIII) taxifolin rhamnoside, (XIX) apigenin-C-diglucoside, (XX) rutin, (XXI) luteolin-7-O-rhamnoglucoside, (XXII) quercetin-3-O-galactoside, (XXIII) quercetin-3-O-glucoside, (XXIV) luteolin-7-O-rhamnoglucoside isomer, (XXV) kaempferol-3-O-rhamnoglucoside, (XXVI) isorhamnetin-3-O-rhamnoglucoside, (XXVII) chrysoeriol-7-O-rhamnoglucoside, (XXVIII) isorhamnetin-3-O-glucoside, (XXIX) chrysoeriol-7-O-rhamnoglucoside isomer, (XXX) chrysoeriol-7-O-glucoside, (XXXI) quercetin, (XXXII) luteolin, and chrysoeriol (XXXIII). The major components were chelidonic acid at 29.44 mg/kg and di-caffeoyl shikimic acid isomers at 9.49 mg/kg wet weight, respectively. Consumption of Moroccan Medjool date palm fruits should contribute to a healthy diet.

Characterization of Phenolic Compounds in Wine Lees.

The effect of vinification techniques on phenolic compounds and antioxidant activity of wine lees are poorly understood. The present study investigated the antioxidant activity of white and red wine lees generated at early fermentation and during aging. In this study, the total phenol content (TPC), total tannin content (TTC), mean degree of polymerization (mDP), and antioxidant activities of five white and eight red wine lees samples from different vinification backgrounds were determined. The results showed that vinification techniques had a significant (p < 0.05) impact on total phenol and tannin content of the samples. White wine lees had high mDP content compared with red ones. Catechin (50–62%) and epicatechin contents were the predominant terminal units of polymeric proanthocyanidin extracted from examined samples. Epigallocatechin was the predominant extension unit of white wine lees, whereas epicatechin was the predominant compound in red wine marc. The ORAC (oxygen radical absorbance capacity) assay was strongly correlated with the DPPH (α,α-diphenyl-β-picrylhydrazyl) assay, and the results showed the strong antioxidant activities associated with red wine lees (PN > 35 mg Trolox/g FDM) (PN: Pinot noir lees; FDM: Freeze-dried Material). This study indicates that tannin is one of the major phenolic compounds available in wine lees that can be useful in human and animal health applications.

Identification and characterization of phenolic compounds extracted from barley husks by LC-MS and antioxidant activity in vitro

Phenolic compounds were extracted from Tunisian barley husks obtained through a pearling process, by using two different extraction solvents: acid treatment with sulfuric acid and alkaline delignification with sodium hydroxide. Their antioxidant properties in vitro were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and butylated hydroxyanisole (BHA). Antioxidants composition was evaluated with LC-MS analysis. Results suggest that the best yield of crude extracts with high level of phenolic compounds exhibiting strong antioxidant activities were found after pre-hydrolysis and delignification step of barley husks. The lowest average total phenolic content found was 763.665 mg/100 g, presenting an EC50 value of 0.93 g/L, four higher antioxidant levels than BHA (0.24 g/L). All extracted fractions showed high contents of p-coumaric acid (≥491.189 mg/100 g), trans-ferulic acid (≥501.475 mg/100 g) and syringic acid (≥192.228 mg/100 g). These results contribute to enhancing the value of barley husks as a good source of natural antioxidants, which serve as new functional food ingredients and dietary supplements.

Optimization of pressurized liquid extraction by response surface methodology of Goji berry (Lycium barbarum L.) phenolic bioactive compounds.

Pressurized liquid extraction (PLE) has been used for the first time in this work to extract phenolic compounds from Goji berries according to a multilevel factorial design using response surface methodology. The global yield (% w/dw, weight/dry-weight), total phenolic content (TPC), total flavonoid (TF) and antioxidant activity (determined via ABTS assay, expressed as TEAC value) were used as response variables to study the effects of temperature (50-180°C) and green solvent composition (mixtures of ethanol/water). Phenolic compounds characterization was performed by high performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS). The optimum PLE conditions predicted by the model were as follows: 180°C and 86% ethanol in water with a good desirability value of 0.815. The predicted conditions were confirmed experimentally and once the experimental design was validated for commercial fruit samples, the PLE extraction of phenolic compounds from three different varieties of fruit samples (Selvatico mongolo, Bigol, and Polonia) was performed. Nine phenolic compounds were tentatively identified in these extracts, including phenolic acids and their derivatives, and flavonols. The optimized PLE conditions were compared to a conventional solid-liquid extraction, demonstrating that PLE is a useful alternative to extract phenolic compounds from Goji berry.

Characterization of phenolic compounds in tincture of edible Nepeta nuda: development of antimicrobial mouthwash.

The activity of edible Nepeta nuda L. (Lamiaceae) tincture and Listerine towards a selected group of oral pathogenic microorganisms (4 bacterial and 9 fungal strains) has been explored. Their potentials to inhibit the formation of biofilm and to diminish established biofilm have been compared. The amount of N. nuda tincture and swishing time necessary for reaching better or equivalent antimicrobial effect than that of Listerine have been predicted. Phenolic compounds in N. nuda tincture are determined by LC-DAD/ESI-MSn. Both Listerine and N. nuda tincture possess good antimicrobial potentials (MIC in the range of 0.8-15 μL per well) including inhibition of biofilms. Rosmarinic acid and verminoside are the most dominant phenolic compounds present in the N. nuda tincture. Based on in vitro results, we infer that it is more desirable to swish 20 mL of mouthwashes (Listerine and N. nuda tincture, 100 mg mL-1) for 30 s when dealing with selected microorganisms in general and for 60 s (N. nuda tincture) when dealing with bacterial biofilms.

Characterization of phenolic compounds in petal extracts of rose

The experiment was carried out during 2015–16 to evaluate the phenolic content and its chemical composition in rose petal extracts. Among 13 varieties tested, Ashwini recorded the highest phenolic content (427.59 mg GAE/100g FW) followed by Dr. S.S. Bhatnagar (379.24 mg GAE/100g FW) and Nehru Centenary (342.67 mg GAE/100g FW), whereas Pusa Ajay showed the lowest phenolic content (101.03 mg GAE/100g FW). High performance liquid chromatography (HPLC) analysis identified the presence of five major phenolic compounds in rose petal extract, viz. quercetin, catechin, epicatechin, rutin and 3-hydroxy cinnamic acid. From the present study it can be concluded that rose petals are rich in phenols and can be further utilised as natural source of antioxidants. Phenol rich varieties can be selected for processing extracts with health promoting properties or can be incorporated into functional foods with bioactive properties related to oxidative stress.

Direct ultrasound-assisted extraction and characterization of phenolic compounds from fresh houseleek (Sempervivum marmoreum L.) leaves

The effects of ultrasound power and frequency on the yield of total extractive substances (TES), total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (AOA) of fresh houseleek leaves extracts obtained by direct ultrasound-assisted extraction (DUAE) were studied. Preliminary extraction of plant material was performed using methanol, acetone and 2-propanol by Soxhlet extraction. It was found that maximum TES yield could be obtained by methanol extraction (2.91?0.02), followed by acetone and 2-propanol with a TES yield of 2.32?0.01 and 2.01?0.03 g per 100 g of fresh plant material, respectively. In the fresh houseleek leaves extracts obtained by DUAE and methanol as the chosen solvent, TPC, TFC and AOA were in the ranges of: 40.5?85.9 mg gallic acid/g dry extract, 12.7?19.3 mg rutin/g dry extract and 24.6?108.2?g/ml, respectively. The results showed that the increase in the ultrasound power and extraction time have positive and significant (p &lt; 0.05) effects on the TPC, TFC and AOA, while the increase in the ultrasound frequency leads to a decrease in the TPC, TFC and AOA of the extracts. A chromatographic analysis of crude extract identified the following: kaempferol 3-O-(6??-O-malonylglucoside)- 7-O-glucosyde, kaempferol 3-O-glucoside-7-O-rhamnoside, luteolin 5-O-(6??-O-malonylglucoside), kaempferol 3-O-(6??-O-acetylglucoside)-7-O-rhamnoside, genkwanin 5-O-glucoside, luteolin 5-O-(6??-O-malonylglucoside), kaempferol 3-O-(6??-O-malonylglucoside), kaempferol 3-O-rhamnoside, quercetin, genkwanin 4?-O-glucoside and hyperoside.

High resolution LC-MS characterization of phenolic compounds and the evaluation of antioxidant properties of a tropical purple radish genotype

This study reports qualitative profiling of the phenolic compounds in an indigenously developed purple radish genotype VRRAD-151 using ultra performance liquid chromatography with quadrupole time of flight mass spectrometry. The root and leaf samples were harvested at the horticultural maturity stage of the genotype. Roots were divided into the periderm, and xylem, and the leaf samples were divided into petiole, and lamina, and these were separately extracted with methanol before the LC-MS analysis. A total of 66 compounds, including 23 flavonols, 1 dihydroflavonols, 4 flavonones, 4 flavones, 28 anthocyanins, 2 isoflavonoids, 3 phenolic acids, and 1 hydroxybenzaldehyde were putatively identified based on high resolution accurate mass analysis with the data processing through UNIFI®, which is a comprehensive compound identification software solution. An in-house developed database comprising the secondary metabolites of polyphenols was used for the screening purpose, and each phenolic compound was identified based on the detection of the precursor ion, and at least one characteristic fragment ion, each with less than 5 ppm of mass error. Anthocyanins were the most abundant type of phenolics exhibiting 59% in leaf petiole, 80% in root periderm, and 90% in root xylem. The relative concentration of anthocyanins was lower (11%) in the leaf lamina. Cyanidins were the most predominant anthocyanins accounting for 54, 100, 90 and 65%, in leaf lamina, leaf petiole, root periderm and root xylem, respectively. Eight anthocyanins and 25 flavonols (except kaempferol-3-O-p-coumaryl-shophoroside-7-O-glucoside) are tentatively new identifications and reported for the first time in radish. Flavonols were found to be the predominant group of phenolic compounds in the leaf lamina, and interestingly, the gradient of antioxidant activity followed the (relative) concentration gradient of flavonols in the samples. The relative antioxidant activity of various fractions when compared with each other, followed the trend: leaf lamina > root periderm > leaf petiole ≈ root xylem. Based on the results it can be reflected that this genotype can be utilized as a functional food for management of various human and animal diseases. Since the detected anthocyanins were mostly present in acylated forms, this genotype can function as a potential source of stable natural colorants.