Comparison of flavonoid profiles of Agauria salicifolia (Ericaceae) by liquid chromatography-UV diode array detection-electrospray ionisation mass spectrometry

Valorisation of Three Underutilised Native Australian Plants: Phenolic and Organic Acid Profiles and In Vitro Antimicrobial Activity

Tasmannia lanceolata, Diploglottis bracteata and Syzygium aqueum are understudied native Australian plants. This study aimed to characterise the non-anthocyanin phenolic and organic acid profiles of the aqueous extracts obtained from the leaves of T. lanceolata and fruits of D. bracteata and S. aqueum by UHPLC-Q-Orbitrap-MS/MS and UHPLC-TQ-MS/MS. A total of 39, 22, and 27 non-anthocyanin polyphenols were tentatively identified in T. lanceolata, D. bracteata, and S. aqueum extracts, respectively. Furthermore, sugars and ascorbic acid contents as well as in vitro antioxidant and antimicrobial activities of the extracts were determined. Response surface methodology was applied to achieve an extract blend with a strong inhibitory effect against Pseudomonas viridiflava, the main cause of soft rot in vegetables, Bacillus subtilis, Rhodotorula diobovata and Alternaria alternata. The identified compounds including organic acids (e.g., quinic, citric and malic acids) and polyphenols (e.g., catechin, procyanidins, and ellagitannins) might contribute to the observed antimicrobial activity. Furthermore, this study provides the most comprehensive phenolic profiles of these three underutilised native Australian plants to date.

Nébié RH, Palé E, Nacro M. HPTLC/HPLC-mass spectrometry identification and NMR characterization of major flavonoids of wild lemongrass (Cymbopogon giganteus) collected in Burkina Faso

Cymbopogon giganteus is a medicinal plant from Burkina Faso whose leaves are used in many traditional recipes to treat several diseases. However, no scientific studies have been reported on the analysis of bioactive molecules of the plant. It is therefore for the first time that flavonoids are isolated from the leaves of the Burkina Faso species. The aim was to quantify, isolate and characterize the major flavonoids in methanol extracts of the plant leaves by spectrophotometry, chromatography and NMR respectively. Flavonoid content analysis showed values ranging from 134 to 270 μg QE/mg extract. HPTLC-MS identified six peaks corresponding to phenolic compounds. By a succession of chromatography on column and by chemical, physicochemical and physical methods, we could isolate and characterize three flavonoids: epicatechin, luteolin 8-C-glucosid and luteolin 6-C-glucosid which structures were characterized by NMR. This study has provided relevant results to contribute to the knowledge of bio-active molecules of the local flora of Burkina Faso for their consideration as an alternative to synthetic products in various fields.

Chemical constituents and aldose reductase inhibitory activities of Betula alba bark and leaves

Systematic phytochemical investigation of the bark and leaves of Betula alba was independently conducted. A new cyclic diarylheptanoid glucoside (1), five diarylheptanoids (2-6), a phenylethanoid (7), a methyl salicylate glycoside (8), a dihydrobenzofuran glucoside (9), an arylbutanoid glycoside (10), two lignan glycosides (11 and 12), a flavanone glucoside (13), and a triterpene (14) were isolated from the bark of B. alba. On the other hand, two cyclic diarylheptanoids (15 and 16), five flavonoids (17-21), a phenylpropanoid (22), a phenylbutanoid glucoside (23), and a monoterpene glucoside (24) were obtained from the leaves of B. alba. The structures of the isolated compounds (1-24) were identified on the basis of one- and two-dimensional NMR spectroscopic data. Compounds 1-24 were subsequently examined for aldose reductase (AR) inhibitory activity. Compounds 14 and 17-20 moderately inhibited AR activity with IC₅₀ values ranging from 6.6 to 34 µM.

Comparison of the polyphenolic profile and antibacterial activity of the leaves, fruits and flowers of Rhododendron ambiguum and Rhododendron cinnabarinum

Background

Rhododendron species have been traditionally used in countries like China, Nepal, Russia and North America for treating human diseases. These species are known to be a good source of polyphenolic plant secondary plant metabolites. They are known to have beneficial health properties for humans and have been used to treat diseases like asthma, skin diseases. In this contribution we investigate the phenolic profile and antibacterial activity of extracts from several plant organs including for the first time from leaves of different development stages.

Methods

In this study, the polyphenolic profile of fruits, flowers and leaves of different ages of Rhododendron ambiguum and Rhododendron cinnabarinum were studied by using HPLC–MS and compounds identified based on high resolution masses and identity of tandem mass spectra, UV/VIS spectra and retention times if compared to standards.

Results

Fifty-nine different polyphenols including isomers were identified in these species by their fragmentation pattern and high resolution data. Also, the antibacterial activity of these parts (leaves, fruits and flowers) against gram-positive bacteria was studied.

Conclusion

The leaves and fruits contained more polyphenols than the flowers. With the exception of flowers, the fruits and leaves of both species were also determined to have a significant antibacterial effect against four gram-positive bacteria.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-017-2601-1) contains supplementary material, which is available to authorized users.

Anti-oxidant, anti-inflammatory, analgesic and antipyretic activities of grapevine leaf extract (Vitis vinifera) in mice and identification of its active constituents by LC-MS/MS analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Vitis vinifera is used in traditional medicine for diarrhea, hepatitis and stomachaches. The objective of this study was to investigate the anti-oxidant, anti-inflammatory, analgesic and antipyretic properties of the hydroalcoholic leaf extract of Vitis vinifera (EVV) on experimental models to provide scientific basis for its use.

MATERIALS AND METHODS

The EVV was chemically characterized by LC-MS/MS analyses. The in vitro antioxidant activities of the EVV extract were measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and Ferric reducing antioxidant power assay (FRAP). Analgesic activity using acetic acid induced writhing and formalin test in mice, anti-inflammatory activity using carrageenan induced paw oedema and acetic acid-induced vascular permeability in mice, and antipyretic activity using Brewer's yeast induced pyrexia in rats were evaluated at 100mg/kg, 200mg/kg, and 400mg/kg doses of the extract.

RESULTS

The extract (EVV) was found to contain resveratrol, quercetin, catechin, flavone, flavonols, anthocyanin, gallic acid and epicatechin. EVV produced significant dose-response anti-inflammatory activity against carrageenan-induced paw edema. EVV at dosages of 100, 200 and 400mg/kgbw significantly reduced carrageenan-induced paw edema by 34.48% (P<0.05), 36.20% (P<0.05), and 41.37% (P<0.05) at 5h after carrageenan injection, respectively. Also EVV extract reduces significantly acetic acid-induced vascular permeability in mice dose dependently. EVV (100, 200 and 400mg/kgbw) produced significant dose-response analgesic activity in the formalin test. However, the low percentage inhibition (50%) suggests that it is not a centrally acting analgesic. Extract at dosages of 100, 200 and 400mg/kg bw, p.o. significantly reduced acetic acid-induced writhing by 48.15% (p<0.05), 57.97% (p<0.05), and 68.09% (p<0.05), respectively. The extract also caused marked dose-dependent inhibition of formalin-induced pain in the second phase (p<0.05). Statistical significant reduction in rectal temperatures was observed in standard group at 21 and 23h, and in 200mg/kg and 400mg/kg doses of the extract at 23h (p<0.05) compared with the 19h.

CONCLUSIONS

The results obtained indicated potential analgesic, anti-inflammatory and antipyretic effects of them hydroalcoholic leaf extract of V. vinifera observed at doses tested which support the claim for the traditional use of the plant in the treatment of various inflammatory and pain diseases.

UHPLC-PDA-ESI-TOF/MS metabolic profiling of Arctostaphylos pungens and Arctostaphylos uva-ursi. A comparative study of phenolic compounds from leaf methanolic extracts

The aim of this study was to get a rapid metabolic fingerprinting and to gain insight into the metabolic profiling of Arctostaphylos pungens H. B. K., a plant morphologically similar to Arctostaphylos uva-ursi (L.) Spreng. (bearberry) but with a lower arbutin (Arb) content. According to the European Pharmacopoeia the Arb content in the dried leaf of A. uva-ursi (L.) Spreng. must be at least 7% (wt/wt) but other species, like A. pungens, are unintentionally or fraudulently marketed instead of it. Therefore, methanolic leaf extracts of nine A. uva-ursi and six A. pungens samples labeled and marketed as "bearberry leaf" have been analyzed. A five-minute gradient with a UHPLC-PDA-ESI-TOF/MS on an Acquity BEH C18 (50×2.1 mm i.d.) 1.7 μm analytical column has been used for the purpose. A comprehensive assignment of secondary metabolites has been carried out in a comparative study of the two species. Among twenty-nine standards of natural compounds analyzed, fourteen have been identified, while other fifty-five metabolites have been tentatively assigned. Moreover, differences in both metabolic fingerprinting and profiling have been evidenced by statistical multivariate analysis. Specifically, main variations have been observed in the relative content for Arb, as expected, and for some galloyl derivative like tetra- and pentagalloylglucose more abundant in A. uva-ursi than in A. pungens. Furthermore, differences in flavonols profile, especially in myricetin and quercetin glycosilated derivatives, were observed. Based on principal component analysis myricetrin, together with a galloyl arbutin isomer and a disaccharide are herein proposed as distinctive metabolites for A. pungens.

Flavonoids in Juglans regia L. leaves and evaluation of in vitro antioxidant activity via intracellular and chemical methods

Flavonoids are rich in Juglans regia L. leaves. They have potent antioxidant properties, which have been related to regulating immune function and enhancing anticancer activity. Herein, qualitative and quantitative determination of flavonoids from J. regia leaves was carried out using high performance liquid chromatography coupled with tandem mass spectrometry with electrospray ionization and negative ion detection (HPLC-ESI-MS/MS) by comparison of the retention times and mass spectral fragments with standard substances or related literatures. Seventeen compounds were identified and major components are quercetin-3-O-rhamnoside (453.11 μg/g, dry weight), quercetin-3-O-arabinoside (73.91 μg/g), quercetin-3-O-xyloside (70.04 μg/g), kaempferol-O-pentoside derivative (49.04 μg/g), quercetin-3-O-galactoside (48.61 μg/g), and kaempferol-O-pentoside (48.46 μg/g). The in vitro intracellular antioxidation indicated that flavonoids from J. regia leaves could reduce the reactive oxygen species (ROS) level in RAW264.7 cells and showed good radical scavenging activities. These results proved to be more related to the flavonoids that could be considered in the design of new formulations of dietary supplements or functional foods.

UPLC-MS/MS method for determination of avicularin in rat plasma and its application to a pharmacokinetic study

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of avicularin in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile-methanol (9:1, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 1.60 min and the elution of avicularin was at 1.20 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 434.1→301.3 for avicularin and m/z 237.2→194.3 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 10-3000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of avicularin in plasma was in the range of 84.2-89.5%. Intra-day and inter-day precision were both <12%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg avicularin in rats.

Determination of Polyphenol Components of Korean Prostrate Spurge (Euphorbia supina) by Using Liquid Chromatography-Tandem Mass Spectrometry: Overall Contribution to Antioxidant Activity

The Korean prostrate spurge Euphorbia supina is a weed that has been used in folk medicine in Korea against a variety of diseases. Nine polyphenols were characterized for this plant by using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and the results were compared with the literature data. The individual components were validated using the calibration curves of structurally related external standards and quantified for the first time by using the validated method. Correlation coefficients (r (2)) were >0.9907. The limit of detection and limit of quantification of the method were >0.028 mg/L and 0.094 mg/L, respectively. Recoveries measured at 50 mg/L and 100 mg/L were 76.1-102.8% and 85.2-98.6%, respectively. The total amount of the identified polyphenols was 3352.9 ± 2.8 mg/kg fresh plant. Quercetin and kaempferol derivatives formed 84.8% of the total polyphenols. The antioxidant activities of the flavonoids were evaluated in terms of 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation-scavenging activity, and the reducing power showed a dose-dependent increase. Cell viability was effectively suppressed at polyphenol mixture concentrations >250 mg/L.

Isolation by pressurised fluid extraction (PFE) and identification using CPC and HPLC/ESI/MS of phenolic compounds from Brazilian cherry seeds (Eugenia uniflora L.)

Brazilian cherry seeds are a waste product from juice and frozen pulp production and, the seeds composition was investigated to valorize this by-product. Compounds separation was performed with ethanol by pressurised fluid extraction (PFE). Here we determine the effect of temperature (T), static time (ST), number of cycles (C), and flush volume (VF) on the yield, composition and total phenolic content (TPC) of the seed extracts. T, ST and their interaction positively influenced yield and TPC. Extracts were fractionated by high performance liquid chromatography (HPLC) and centrifugal partition chromatography (CPC). The collected fractions characterizations were made by electrospray ionisation mass spectrometry (ESI/MS) and high resolution mass spectrometry (HRMS) indicated the presence of ellagic acid pentoside and deoxyhexose, quercitrin and kaempferol pentoside. All of these compounds have antioxidant properties and normally are found in plant extracts. These results confirm that Brazilian cherry seed extract is a potentially valuable source of antioxidants.

A RP-HPLC-DAD-APCI/MSD method for the characterisation of medicinal Ericaceae used by the Eeyou Istchee Cree First Nations

INTRODUCTION

Ericaceae medicinal plants are traditionally used by the Eeyou Istchee Cree and other northern peoples of North America to treat type 2 diabetic symptoms. Because of the importance of phenolics as potential cures for degenerative diseases including type 2 diabetes, an analytical method was developed to detect them in the leaf extracts of 14 Ericaceae plants.

OBJECTIVE

To develop an optimised method which is applicable to a relatively large number of Ericaceae plants using their leaf extracts. For this purpose phenolics with a wide range of polarity, including a glucosylated benzoquinone, two phenolic acids, three flavanols, a flavanone, a flavone and five flavonols, were included in this study.

METHODOLOGY

Characterisation of phytochemicals in extracts was undertaken by automated matching to the UV spectra to those of an in house library of plant secondary metabolites and the authentication of their identity was achieved by reversed phase-high-performance chromatography-diode array detection-atmospheric pressure chemical ionisation/mass selective detection.

RESULTS

Twenty-six phenolics were characterised within 26 min of chromatographic separation in 80% ethanol extracts of 14 Ericaceae plants. The calibration curves were linear within 0.5-880 microg/g dry mass of the plant with regression values better than 0.995. The limits of detection ranged from 0.3 for microg/mL for (+)-catechin to 2.6 microg/mL for chlorogenic acid. This is a first study dealing with relatively large number of Ericaceae extracts and is applicable to other plants of same family.

Analysis of phenolic compounds from different morphological parts of Helichrysum devium by liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection

A simple and rapid method has been used for the screening and identification of the main phenolic compounds from Helichrysum devium using high-performance liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection (LC-DAD/ESI-MS(n)). The total aerial parts and different morphological parts of the plant, namely leaves, flowers and stems, were analyzed separately. A total of 34 compounds present in the methanolic extract from Helichrysum devium were identified or tentatively characterized based on their UV and mass spectra and retention times. Three of these compounds were positively identified by comparison with reference standards. The phenolic compounds included derivatives of quinic acid, O-glycosylated flavonoids, a caffeic acid derivative and a protocatechuic acid derivative. The characteristic loss of 206 Da from malonylcaffeoyl quinic acid was used to confirm the malonyl linkage to the caffeoyl group. This contribution presents one of the first reports on the analysis of phenolic compounds from Helichrysum devium using LC-DAD/ESI-MS(n) and highlights the prominence of quinic acid derivatives as the main group of phenolic compounds present in these extracts. We also provide evidence that the methanolic extract from the flowers was significantly more complex when compared to that of other morphological parts.