O-glycosylated Flavonoids Research Articles

Antiviral Activity of Flavonoids from Bauhinia holophylla Leaves against Zika virus

Zika virus (ZIKV) is involved in the etiology of serious nervous system pathologies. Currently, there are no specific and effective vaccines or antiviral drugs to prevent the diseases caused by ZIKV. This study aimed to assess the activity of flavonoids present in crude hydroethanolic extract (CHE) and fractions obtained from B. holophylla leaves against ZIKV. O-glycosylated flavonoids were characterized by high-performance liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS/MS). The cytotoxic concentration and the effective concentration for 50% of the cells (CC50 and EC50, respectively) were determined, and the selectivity index (SI) was calculated. Molecular networks were constructed based on the chemical composition of the samples and global antiviral activity data using the Global Natural Products Social Molecular Networking (GNPS) platform. Protein–ligand docking was performed in the NS2B-NS3 protease, NS3 helicase, and NS5 methyltransferase of the ZIKV. CHE showed greater antiviral activity at a multiplicity of infection (MOI) of 1.0, with an EC50 of 11.93 µg/mL, SI = 13.38, and reduced cytopathic effects. Molecular networks indicated that O-glycosylated flavonoids are responsible for the activity against ZIKV, being quercetin-O-deoxyhexoside more selective and effective. Molecular docking confirmed the inhibitory activity of quercetin-O-deoxyhexoside, which showed an affinity for the tested targets, especially for NS2B-NS3 protease. The results showed that B. holophylla has flavonoids with potential for future therapeutic applications against ZIKV.

Identification of three types of O-glycosylated flavonoids in Dendrobium loddigesii, Dendrobium primulinum, Dendrobium crepidatum, Dendrobium porphyrochilum, and Dendrobium hancockii using mass spectrometry.

Flavonoids, representing the pharmacologically active ingredients, are found widely in Dendrobium species. The biodiversity of Dendrobium makes the identification of its varieties all the more complicated. Previous studies showed that C-glycosylated flavones and a few O-glycosylated flavonols could be used in the identification of various Dendrobium species. Accordingly, this study further explores the significance of the identification of various types of O-glycosylated flavonoids in Dendrobium species. High-performance liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry (HPLC-ESI-MSn ) was used to identify the chemical constituents in five types of Dendrobium: Dendrobium loddigesii, Dendrobium primulinum, Dendrobium crepidatum, Dendrobium porphyrochilum, and Dendrobium hancockii. A total of 41 O-glycosylated flavonoids and 3 C-glycosylated flavones were identified, among which O-glycosylated dihydroflavones were the main flavonoids in D. loddigesii and D. primulinum, O-Glycosylated flavonols were rich in both D. crepidatum and D. porphyrochilum characterized by the main aglycone, substituted sugars, and their structural characteristics, and O-glycosylated flavones were the main constituents in D. hancockii. In this study, three types of O-glycosylated flavonoids in the five Dendrobium species were determined to have certain significance. This also provides a reference for the identification of other O-glycosylated flavonoids in Chinese herbs.

Margaritaria nobilis L.F. (Phyllanthaceae): Ethnopharmacology and Application of Computational Tools in the Annotation of Bioactive Molecules.

Margaritaria nobilis is a shrubby species widely distributed in Brazil from the Amazon to the Atlantic Rainforest. Its bark and fruit are used in the Peruvian Amazon for disinfecting abscesses and as a tonic in pregnancy, respectively, and its leaves are used to treat cancer symptoms. From analyses via UHPLC-MS/MS, we sought to determine the chemical profile of the ethanolic extract of M. nobilis leaves by means of putative analyses supported by computational tools and spectral libraries. Thus, it was possible to annotate 44 compounds, of which 12 are phenolic acid derivatives, 16 are O-glycosylated flavonoids and 16 hydrolysable tannins. Among the flavonoids, although they are known, except for kaempferol, which has already been isolated from this species, the other flavonoids (10, 14, 15, 21, 24–26, 28–30, 33–35, 40 and 41) are being reported for the first time in the genus. Among the hydrolysable tannins, six ellagitannins present the HHDP group (6, 19, 22, 31, 38 and 43), one presents the DHHDP group (5), and four contain oxidatively modified congeners (12, 20, 37 and 39). Through the annotation of these compounds, we hope to contribute to the improved chemosystematics knowledge of the genus. Furthermore, supported by a metric review of the literature, we observed that many of the compounds reported here are congeners of authentically bioactive compounds. Thus, we believe that this work may help in understanding future pharmacological activities.

Bioassay-Guided Fractionation of Siparuna glycycarpa n-Butanol Extract with Inhibitory Activity against Influenza A(H1N1)pdm09 Virus by Centrifugal Partition Chromatography (CPC).

Siparuna glycycarpa occurs in the Amazon region, and some species of this genus are used in Brazilian folk medicine. A recent study showed the inhibitory effect of this species against influenza A(H1N1)pdm09 virus, and in order to acquire active fractions, a polar solvent system n-butanol-methanol-water (9:1:10, v/v) was selected and used for bioassay-guided fractionation of n-butanol extract by centrifugal partition chromatography (CPC). The upper phase was used as stationary phase and the lower phase as mobile (descending mode). Among the collected fractions, the ones coded SGA, SGC, SGD, and SGO showed the highest antiviral inhibition levels (above 74%) at 100 µg·mL−1 after 24 h of infection. The bioactive fractions chemical profiles were investigated by LC-HRMS/MS data in positive and negative ionization modes exploring the Global Natural Products Social Molecular Networking (GNPS) platform to build a molecular network. Benzylisoquinoline alkaloids were annotated in the fractions coded SGA, SGC, and SGD collected during elution step. Aporphine alkaloids, O-glycosylated flavonoids, and dihydrochalcones in SGO were acquired with the change of mobile phase from lower aqueous to upper organic. Benzylisoquinolinic and aporphine alkaloids as well as glycosylated flavonoids were annotated in the most bioactive fractions suggesting this group of compounds as responsible for antiviral activity.

Ethnopharmacological investigations of the leaves of Cecropia pachystachya Trécul (Urticaceae): A native Brazilian tree species

Ethnopharmacological relevanceCecropia pachystachya Trécul (Urticaceae) is a medicinal plant popularly known as ‘embaúba’. In Brazil, the leaves of this species are used for the treatment of various kidney and cardiovascular diseases. However, there are no detailed studies on the renal and cardiovascular activities of this species. No studies on the anatomy or the quality control of this herbal drug is available thus far. AimThis study was aimed to investigate the ethnopharmacological properties of the leaves of C. pachystachya. Material and methodsThe leaves of C. pachystachya were analyzed by light and scanning electron microscopy for pharmacobotanical and anatomical characterization. The ethanol-soluble fraction of C. pachystachya leaf extract (ESCP) was characterized by high-performance liquid chromatograph equipped with diode array detector and mass spectrometry (HPLC-DAD-MS). The acute oral toxicity of ESCP on female Wistar rats was assessed. The acute and prolonged diuresis and antioxidant effects of ESCP (30, 100, and 300 mg/kg) were evaluated in male Wistar rats. In addition, the hypotensive effects of the ESCP as well as the vasodilatory activity in isolated and perfused mesenteric vascular beds were investigated. ResultsThe anatomical markers obtained in this study can help in the identification of C. pachystachya, as well as to distinguish it from the other ‘embaúbas’. The metabolites found in the ESCP were phenolic compounds, mainly C- and O-glycosylated flavonoids. The ESCP did not exhibit any toxic effects at a dose of 2000 mg/kg. Significant diuretic activities were observed at the doses of 30, 100, and 300 mg/kg. In addition, a significant modulating activity of the tissue redox state was observed after prolonged treatment. On the other hand, no hypotensive or vasodilator activity was observed. ConclusionThe key findings of the present study can contribute to the taxonomy, species identification and quality control of C. pachystachya. Chemical studies have shown the presence of glycosylated flavonoids, phenylpropanoid derivative and proanthocyanidins. The pharmacological studies showed significant diuretic and antioxidant effects of C. pachystachya leaf extract, indicating a possible validation of its popular medicinal use.

Can Statistical Evaluation Tools for Chromatographic Method Development Assist in the Natural Products Workflow? A Case Study on Selected Species of the Plant Family Malpighiaceae.

Proper chromatographic methods may reduce the challenges inherent in analyzing natural product extracts, especially when utilizing hyphenated detection techniques involving mass spectrometry. As there are many variations one can introduce during chromatographic method development, this can become a daunting and time-consuming task. To reduce the number of runs and time needed, the use of instrumental automatization and commercial software to apply Quality by Design and statistical analysis automatically can be a valuable approach to investigate complex matrices. To evaluate this strategy in the natural products workflow, a mixture of nine species from the family Malpighiaceae was investigated. By this approach, the entire data collection and method development procedure (comprising screening, optimization, and robustness simulation) was accomplished in only 4 days, resulting in very low limits of detection and quantification. The analysis of the individual extracts also proved the efficiency of the use of a mixture of extracts for this workflow. Molecular networking and library searches were used to annotate a total of 61 compounds, including O-glycosylated flavonoids, C-glycosylated flavonoids, quinic/shikimic acid derivatives, sterols, and other phenols, which were efficiently separated by the method developed. These results support the potential of statistical tools for chromatographic method optimization as an efficient approach to reduce time and maximize resources, such as solvents, to get proper chromatographic conditions.

Comprehensive evaluation of the antioxidant capacity of Sceptridium ternatum using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis.

Sceptridium ternatum is a medicinal herb with multiple health benefits. However, its antioxidant activity and active components have not been clarified. In this study, the antioxidant capacity of S. ternatum was comprehensively investigated using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis. First, the phenolic content, flavonoid content, and radical scavenging ability of S. ternatum were parallelly determined using colorimetric methods performed in 96-well microplates. The flavonoid content, rather than the phenolic content, was highly correlated with its antioxidant activity. Sceptridium ternatum was shown to be a rich source of flavonoids, with a highest flavonoid yield of 3.44 ± 0.11mg/g. Subsequently, 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography experiment and quadrupole time-of-flight mass spectrometry analyses were carried out for rapid screening of the individual antioxidants. A total of 14 O-glycosyl flavonoids with quercetin or kaempferol aglycone have been characterized. Particularly, quercetin 3-O-rhamnoside-7-O-glucoside exhibited the most potent antioxidant ability. Its half-maximal effective concentrations for scavenging 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) radicals were 70.55 ± 2.69 and 106.90 ± 1.76 µg/mL, respectively, which were comparable with those of l-ascorbic acid. Our results indicated that the combined colorimetric and chromatographic methods provided a practical strategy for the discovery of bioactive compounds from natural products.

Antiviral Potential of Spondias mombin L. Leaves Extract Against Herpes Simplex Virus Type-1 Replication Using In Vitro and In Silico Approaches.

Spondias mobin leaves have been traditionally used for treating cold sores. The study investigated the mechanism of antiherpes action of S. mombin extract, fractions, and geraniin. Different concentrations of samples were used to evaluate the in vitro antiherpes activity (anti-HSV-1) in virucidal, post-infection, attachment, and penetration assays. The mechanism of action of geraniin was investigated considering the glycoproteins gB and gD of HSV-1 surface as potential molecular targets. Molecular docking simulations were carried out for both in order to determine the possible binding mode position of geraniin at the activity sites. The binding mode position was posteriorly optimized considering the flexibility of the glycoproteins. The chemical analysis of samples was performed by LC-MS and revealed the presence of 22 substances, which are hydrolysable tannins, O-glycosylated flavonoids, phenolic acids, and a carbohydrate. The extract, tannin-rich fraction and geraniin showed important in vitro virucidal activity through blocking viral attachment but showed no relevant inhibition of viral penetration. The in silico approaches demonstrated a high number of potential strong intermolecular interactions as hydrogen bonds between geraniin and the activity site of the glycoproteins, particularly the glycoprotein gB. In silico experiments indicated that geraniin is at least partially responsible for the anti-herpes activity through interaction with the viral surface glycoprotein gB, which is responsible for viral adsorption. These results highlight the therapeutic potential of S. mombin anti-herpes treatment and provides support for its traditional purposes. However, further studies are required to validate the antiviral activities in vivo, as well as efficacy in humans.

Isolation and characterisation of altissimin: a novel cytotoxic flavonoid C-apioglucoside from Drimia altissima (Asparagaceae)

Flavonoids are a class of biologically active compounds with various proven nutraceutical benefits. In flavonoid C-glycosides, the aglycones are attached to sugar residues via cleavage-resistant C-C bonds which alter typical flavonoid pharmacokinetic properties. In these compounds, the combination of biological activities from the flavonoid moieties and sugar residues create unique and more diverse biological functions than those of O-glycosylated and unsubstituted flavonoids. Through a series of reverse phase chromatography techniques and various spectroscopic methods, the phytochemical investigation of Drimia altissima (L.F.) Ker Gawl., a specie from the Asparagaceae family, led to the isolation and chemical characterisation of a novel C-glucosylflavonoid, altissimin, with a unique apioglucoside arrangement to the apigenin aglycone. Altissimin was found to possess strong in vitro anti-proliferative activity against HeLa cervical cancer cells.

Anchietea pyrifolia A. St.-Hil. as a Cardiovascular-Endowed Species: A Whole-Biological Investigation.

Although leaves of Anchietea salutaris are used in Brazilian traditional medicine, there is no available data in the literature proving its efficacy and safety. Thus, the aim of the study was to perform a meticulous botanical, phytochemical, toxicological, and pharmacological investigation of A. salutaris in Wistar rats. At first, a morphoanatomical characterization of Anchietea pyrifolia leaves and stems was performed. Then, a purified infusion (ethanol-soluble fraction obtained from A. pyrifolia [ESAP]) was obtained followed by its chemical profile elucidation. Furthermore, an acute toxicity test was performed, and the acute and prolonged diuretic and hypotensive effects were also evaluated in Wistar rats. Finally, the vasodilatory responses of ESAP in mesenteric vascular beds were investigated. The main secondary metabolites identified from ESAP were O-glycosylated flavonoids, chlorogenic acids, and phenylpropanoic acid derivatives. ESAP did not promote any toxic effects in female rats nor increased urinary excretion in male rats after a single exposure. However, ESAP significantly reduced renal elimination of sodium, potassium, and chloride after prolonged treatment. An ESAP highest dose promoted significant acute hypotension without affecting blood pressure levels after prolonged use. Furthermore, its cardiovascular effects seem to be related with the calcium-activated potassium channel activation in resistance vessels.

Chemical characterization with in vitro biological activities of Gypsophila species

Methanol-aqueous extracts from the aerial parts of Gypsophila glomerata (GGE), G. trichotoma (GTE) and G. perfoliata (GPE) were investigated for antioxidant potential using different in vitro models, as well as for phenolic and flavonoid contents. The possible anti-cholinesterase, anti-tyrosinase, anti-amylase and anti-glucosidase activities were also tested. The flavonoid variability was analyzed using ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadrupole-Orbitrap high resolution mass spectrometry (HRMS). Eleven C-glycosyl flavones and 4 O-glycosyl flavonoids, including 2”-O-pentosyl-6-C-hexosyl-apigenin/methylluteolin, as well as their mono(di)-acetyl derivatives were found in GGE. Both GGE and GTE shared 2”-pentosyl-6-C-hexosyl-luteolin together with the common saponarin, homoorientin, orientin, isovitexin and vitexin, while di C-glycosyl flavones were evidenced only in GPE.The highest radical scavenging in both ABTS and DPPH assays was noted in GPE, as well as ferric and cupric reducing abilities. However, GTE had the strongest metal chelating activity (17.44 ± 0.51 mg EDTAE/g extract). GPE and GGE were more potent as acetylcholinesterases inhibitors witnessed by 2.09 ± 0.02 mg GALAE/g extract and 1.59 ± 0.09 mgGALAE/g extract, respectively. All flavonoids were found in G. glomerata for the first time. Therefore, further isolation and structural elucidation of newly described acetylated flavonoids are needed in order to determine their relevance in the beneficial properties of the plant.

Functional Characterization of a Flavonoid Glycosyltransferase in Sweet Orange (Citrus sinensis).

Fruits of sweet orange (Citrus sinensis), a popular commercial Citrus species, contain high concentrations of flavonoids beneficial to human health. These fruits predominantly accumulate O-glycosylated flavonoids, in which the disaccharides [neohesperidose (rhamnosyl-α-1,2-glucose) or rutinose (rhamnosyl-α-1,6-glucose)] are linked to the flavonoid aglycones through the 3- or 7-hydroxyl sites. The biotransformation of the flavonoid aglycones into O-rutinosides or O-neohesperidosides in the Citrus plants usually consists of two glycosylation reactions involving a series of uridine diphosphate-sugar dependent glycosyltransferases (UGTs). Although several genes encoding flavonoid UGTs have been functionally characterized in the Citrus plants, full elucidation of the flavonoid glycosylation process remains elusive. Based on the available genomic and transcriptome data, we isolated a UGT with a high expression level in the sweet orange fruits that possibly encodes a flavonoid glucosyltransferase and/or rhamnosyltransferase. Biochemical analyses revealed that a broad range of flavonoid substrates could be glucosylated at their 3- and/or 7-hydrogen sites by the recombinant enzyme, including hesperetin, naringenin, diosmetin, quercetin, and kaempferol. Furthermore, overexpression of the gene could significantly increase the accumulations of quercetin 7-O-rhamnoside, quercetin 7-O-glucoside, and kaempferol 7-O-glucoside, implying that the enzyme has flavonoid 7-O-glucosyltransferase and 7-O-rhamnosyltransferase activities in vivo.

Characterization and Metabolic Diversity of Flavonoids in Citrus Species

Flavonoids are widely distributed in plants and play important roles in many biological processes. Citrus fruits are rich dietary sources of flavonoids. However, there have been very few reports about the comprehensive metabolic profile and natural diversity of flavonoids in different tissues of various Citrus cultivars. In this study, based on the 7416 metabolic signals detected with non-targeted metabolomics approach, Principal Component Analysis revealed the flavedo has the largest differences from other tissues in metabolite levels; as many as 198 flavonoid signals were then detected in 62 Citrus germplasms from 5 species mainly cultivated worldwide, while 117 flavonoids were identified, including 39 polymethoxylated flavonoids (PMFs), 7 flavones, 10 C-O-glycosylflavonoids, 44 O-glycosylflavonoids, 10 C-glycosylflavonoids and 7 newly annotated O-glycosylpolymethoxylated flavonoids. Tissue-specific accumulations were observed: O-glycosylated flavonoids were abundant in all fruit tissues, while PMFs were accumulated preferentially in the flavedo. Among different species, mandarins had the highest levels of PMFs and O-glycosylpolymethoxylated flavonoids, followed by sweet oranges. Based on the flavonoid profiles, 62 germplasms could be clearly grouped into five distinct clusters via hierarchical clustering analysis, which were perfectly matched with their species, with sweet oranges and mandarins clustering closely and being further away from other three species.

Analysis of elicitors in different varieties of corn silk

Plant response to insect damage offers an environmentally sound alternative to pesticides. In this context, a work was conducted in the molecular characterization of different corn silk varieties, to obtain an additional information to a protection study of tomato plant against devastating insect (Helicoverpa zea). Indeed, corn silks transmit volatile compounds that attract H. zea and its natural enemies. Once H. zea installed, the produced flavonoids-C-glycosylated reduce larvae growth. Five corn varieties (Java; Garrison; Sugar Jean; Nova; Golden Bantam) were studied by solid phase micro extraction gas chromatography mass spectrometry (SPME-GC/MS) and liquid chromatography with mass spectrometry multiple reaction monitoring (LC/MS-MRM). Thirty-eight volatile molecules were identified by SPME-GC/MS. These molecules have been quantified by external calibration from four standards (hexenyl acetate, phenyl ethanol, phenyl acetaldehyde, methyljasmonate) of the same families. The concentration of these volatile compounds was low in Sugar Jean variety while the Garrison and Golden Bantam variety exhibited higher concentration in volatiles such as phenylacetaldehyde. In LC/MS-MRM, the study of molecule fragmentation showed unit losses of 60, 90, 120 Da and that of 132, 146, 162 Da, which allowed to distinguish between C- and O-glycosylated flavonoids. Flavone C-glycosides were identified in each silk, such as maysin and apimaysin. Some molecules were present in various amounts in the studied varieties. The relative content of maysin and ax-5”-methane-3'-methoxymaysin was higher in Java variety, while the relative content of apimaysin and eq-4”-OH-maysin were more prevalent in Golden Bantam variety, and that of luteolin O-glucoside was more important in Sugar Jean variety. These two chromatographic techniques allowed differentiating between varieties of corn silk thanks to their chromatographic fingerprint. (Texte integral)

C- and O-glycosyl flavonoids in Sanguinello and Tarocco blood orange (Citrus sinensis (L.) Osbeck) juice: Identification and influence on antioxidant properties and acetylcholinesterase activity

Sanguinello and Tarocco are the blood orange (Citrus sinensis (L.) Osbeck) cultivars most diffused worldwide. Reversed phase liquid chromatography coupled with MS-MS analysis showed that these two varieties have a similar chromatographic pattern, characterised by the presence of C- and O-glycosyl flavonoids. Of the two, Sanguinello was found to be far richer in flavonoids than Tarocco. In the juices, twelve individual components were identified for the first time, namely, four C-glycosyl flavones (lucenin-2, vicenin-2, stellarin-2, lucenin-2 4′-methyl ether and scoparin), three flavonol derivatives (quercetin-3-O-(2-rhamnosyl)-rutinoside, quercetin-3-O-hexoside, quercetin 3-hydroxy-3-methylglutaryl-glycoside), an O-triglycosyl flavanone (narirutin 4′-O-glucoside) and a flavone O-glycosides (chrysoeriol 7-O-neoesperidoside). Moreover, the influence of the identified C- and O-glycosyl flavonoids on the antioxidant and acetylcholinesterase activity of these juices has been evaluated.

Rice (Oryza sativa L.) phenolic compounds under elevated carbon dioxide (CO2) concentration

Previous studies have shown that elevated levels of carbon dioxide [CO2] may increase, decrease, or have no effect on the concentrations of phenolic compounds in plants. The underlying causes of these variations in responses remain poorly understood. In the present study, it was hypothesized that different plant responses come mainly from the duration of exposure to the gas, growing conditions, and sampling procedures. A two-year field study was conducted in open-top chambers (375 vs. 550μmolCO2mol−1air) using a japonica rice variety (Oryza sativa L. cv. Ariete) as the test crop, with plants grown under elevated [CO2] during their entire life cycle. Leaf, stem and root samples were collected at five different growth stages, and submitted to a series of physiological and biochemical measurements. The carbon:nitrogen ratio and total non-structural carbohydrates were increased by elevated [CO2] in all plant tissues. Data showed that under elevated [CO2], there was a reduction in the total phenolic and total flavonoid contents measured during the seedling, tillering, elongation, and flowering stages in all plant organs, probably resulting from a relaxation of the antioxidative system during seed germination. By contrast, the total phenolic and flavonoid contents increased under elevated [CO2] at maturity, a change in response which coincided with acclimation of photosynthesis. The same trends were observed for sixteen individual phenolic compounds, including the allelopathic tricin, the phytoalexin sakuranetin and several O-glycosylated flavonoids of ecological importance. Overall, the results indicated that during the early stages of plant development, photosynthates were mainly used to synthesize proteins and meet the growth demand of the plant. Growth reduction at maturity made more resources available for the synthesis of phenolic compounds.

First evidence of C- and O-glycosyl flavone in blood orange (Citrus sinensis (L.) Osbeck) juice and their influence on antioxidant properties

RP-LC-DAD-ESI-MS-MS separation/identification protocol has been employed for the identification and characterisation of nine C- and O-glycosyl flavonoids in Moro (Citrus sinensis (L.) Osbeck) juice grown in Southern Italy. For the first time we reported the presence of five C-glycosyl flavones (lucenin-2, vicenin-2, stellarin-2, lucenin-2 4′-methyl ether and scoparin), a 3-hydroxy-3-methylglutaryl glycosyl flavonol (3-hydroxy-3-methylglutaryl glycosyl quercetin) and a flavone O-glycosides (chrysoeriol 7-O-neoesperidoside). Moreover, the influence of the identified C- and O-glycosyl flavonoids on the total antioxidant activity of crude juice has been evaluated on the basis of its ability to scavenge DPPH•, OH• and ABTS•+ radicals and to reduce iron.

Polymethoxylated, C- and O-glycosyl flavonoids in tangelo (Citrus reticulata × Citrus paradisi) juice and their influence on antioxidant properties

A separation/identification protocol based on RP-LC-DAD–ESI-MS–MS has been employed for the characterisation of the flavonoid fraction of the juice from tangelos (Citrus reticulata×Citrus paradisi) grown in Southern Italy. Eleven compounds were identified in a single chromatographic course. Of these, two C-glycosyl flavones (lucenin-2 and vicenin-2) and an O-triglycosyl flavanone (narirutin 4′-O-glucoside) were identified for the first time. Fruit juice antioxidant activity was evaluated on the basis of its ability to scavenge DPPH, O2−, OH and ABTS+ radicals, and to reduce iron (FRAP). Moreover, the influence of the identified polymethoxylated, C- and O-glycosyl flavonoids on the total antioxidant activity has been elucidated. We also checked the antimicrobial activity of a broad fraction, containing all the detected flavonoids obtained by preparative HPLC, in terms of MICs for Staphylococcus aureus.

Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae) against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806).

BackgroundThe tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae) is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes.MethodsThe in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS), using direct injection of sample.ResultsDespite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified.ConclusionsThis is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus.

Characterization of Polyphenolic Compounds in Unripe Chinotto (Citrus myrtifolia) Fruit by HPLC/PDA/ESI/MS-MS

The flavonoid and furocoumarin composition was investigated of peel and pulp tissues of unripe fruits of Citrus myrtifolia Rafinesque, an ingredient of the popular soft drink "chinotto". Compound separation and identification was made using an HPLC-PDA detector coupled to ESI/MS/MS in positive and negative mode. Eighteen compounds (3-hydroxy-3-methylglutaryl-, C- and O-glycosyl flavonoids, furocoumarins and polymethoxylated flavones) were identified and quantified. Data indicated that the overall amount of flavonoids and furocoumarins in peel was higher than in the pulp, even though their relative distribution did not significantly change, apart from a different distribution of flavones and a lower content of naringin in the peel.