LC–DAD–ESIMS/MS characterization of antioxidant and anticholinesterase constituents present in the active fraction from Persicaria hydropiper

Persicaria hydropiper or ‘kesum’ is a herb used extensively as flavoring agent in food. The antioxidant activity was evaluated by measuring the hydroperoxide production resulting from linoleic acid oxidation using ferric thiocyanate (FTC) as well as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability. Moreover, inhibition activity against cholinesterase, an enzyme that responsible in several physio-pathological processes, was also determined. Identification of phytochemical constituents in the bioactive fraction of P. hydropiper was carried out by LC–DAD–ESIMS/MS technique. Fifteen compounds were identified including flavonoids, flavonoid glycosides and phenylpropanoid glycosides. Six of the compounds were isolated and their structures were elucidated in order to confirm their identities. The antioxidant and antiacetylcholinesterase activities of the isolated compounds were also evaluated.     

Optimization of SC–CO2 extraction of zerumbone from Zingiber zerumbet (L) Smith

Response surface methodology (RSM) was applied to optimize the variables affecting the Supercritical carbon dioxide (SC–CO₂) extraction of non-polar compounds from Zingiber zerumbet using the Box-Behnken design (BBD). Dependent variables were the percentage of the chemical components in the ginger vis a vis α-caryophyllene (y₁), camphene (y₂), and zerumbone (2,6,10-cycloundecatrien-1-one, 2,6,9,9-tetramethyl-) (y₃). Pressure was the most significant parameter affecting the amount of each compound extracted. When temperature was kept constant and pressure was increased, all of the dependent variables increased concomitantly. Since pressure and temperature are two of the major influential factors in the extraction using SC–CO₂, any combination of these two parameters could be selected to ascertain the optimum combination for a particular compound in the extract. Extraction at 30 °C and 55 MPa with total amount of 30 g of CO₂ used was found to maximize all the responses.     

Fingerprint profile of active components for Artemisia selengensis Turcz by HPLC–PAD combined with chemometrics

An approach was proposed to develop enhanced fingerprint by means of high-performance liquid chromatography (HPLC) with photodiode array detection. The approach was applied to establish enhanced chromatographic fingerprints of various Artemisia selengensis Turcz which is a traditional Chinese medicine (TCM). In comparison with common fingerprint at a fixed wavelength, enhanced fingerprint compiled additional spectral data and was more informative. So it could be used to conduct the quality control of this TCM comprehensively. Thereafter, the chromatographic fingerprint data set was submitted for classification to a suite of chemometrics methods viz. similarity analysis (SA), hierarchical clustering analysis (HCA) and principal component analysis (PCA). Each method highly lighted different properties of the data matrix according to the fingerprints from different types of A. selengensis Turcz. It provided comprehensive information for matching and discrimination of the fingerprints, and appeared to be suited for quality assurance purposes for these similar types of sample.     

Analysis of phenolic compounds in cork from Quercus suber L. by HPLC–DAD/ESI–MS

The aim of the present work was to identify the extractable phenolic compounds present in cork from Quercus suber L. The structures of thirty three compounds were tentatively identified by liquid chromatography coupled to electrospray ionisation mass spectrometry (HPLC–DAD/ESI–MS). The majority of those compounds were gallic acid derivatives, in the form of either galloyl esters of glucose (gallotannins), combinations of galloyl and hexahydroxydiphenoyl esters of glucose (ellagitannins), dehydrated tergallic-C-glucosides or ellagic acid derivatives. Others were found to correspond to low molecular weight phenolic compounds, like acids and aldehydes. Mongolicain, a flavanoellagitannin in which hydrolysable tannin and flavan-3-ol moieties are connected through a carbon–carbon linkage, was also detected in cork from Q. suber L. The results illustrate the rich array of phenolic compounds present in cork.     

Flavonol glucosides in Allium species: A comparative study by means of HPLC–DAD–ESI-MS–MS

Cultivars and consumption typologies of some Allium species can significantly vary from a chemical point of view and even small differences can be important for their characterization and differentiation. Bulbs of three varieties and four consumption typologies of onion (Allium cepa L.) and two varieties of shallot (Allium ascalonicum Hort.) were subjected to HPLC–DAD–ESI-MS–MS analysis. Seven flavonol glucosides were identified in all the samples, two of which, quercetin 3,4′-diglucoside and quercetin 4′-glucoside, represent about the 90% of the overall contents. Cultivars and consumption typologies of the Allium species under study show significant differences in flavonol contents, from the very low quantity of antioxidant compounds in white onion, about 7 mg/kg against 600–700 mg/kg that were found in red and gold varieties, to the enormous content of flavonols that are present in onions of prompt consumption, where quercetin 4′-glucoside exceeds 1 g/kg and quercetin 3-glucoside is present in a ratio higher then 10:1 with respect to its value in the other onion typologies. Shallots are very rich in the two major flavonols.     

Characterisation of aroma active compounds in black truffles (Tuber melanosporum) and summer truffles (Tuber aestivum) by gas chromatography–olfactometry

The aromatic composition of two different species of truffles (black and summer) was evaluated by gas chromatography–olfactometry (GC–O). Volatiles released by the truffles at 25 °C for 7.5 h were collected in a trapping system consisting of 400 mg of LiChrolut EN kept at 0 °C and further eluted with dichloromethane/methanol (95:5). The extract was analysed by two different GC–O strategies: (1) a semiquantitative GC–O study using a panel composed of nine individuals, (three of them truffle experts) and (2) an AEDA (aroma extract dilution analysis) experiment with a small panel of two judges. The results show that the aroma emitted by a typical black truffle is due to at least 17 different aroma molecules, six of which are reported for the first time: 1-hexen-3-one, 2-methyl-3-furanthiol, furaneol, 3-ethylphenol, 3-propylphenol and 5-methyl-2-propylphenol. The most important aroma compounds of black truffle aroma are 2,3-butanedione, dimethyl disulphide (DMDS), ethyl butyrate, dimethyl sulphide (DMS), 3-methyl-1-butanol and 3-ethyl-5-methylphenol. Quantitatively, black truffle emits mostly 3-ethyl-5-methylphenol (more than 50% of the total aroma molecules emitted), 5-methyl-2-propylphenol, β-phenylethanol and 3-ethylphenol. In the case of summer truffle, the most important aroma molecules are DMS, DMDS, methional, 3-methyl-1-butanol, 1-hexen-3-one and 3-ethylphenol. From the quantitative point of view, summer truffle emits mainly β-phenylethanol, DMS and 3-ethylphenol, but the emission is up to 100 times less than that of black truffles.     

Identification and quantification of leaf surface flavonoids in wild-growing populations of Dracocephalum kotschyi by LC–DAD–ESI-MS

Dracocephalum kotschyi Boiss. (Lamiaceae) is an aromatic and perennial herb endemic to Iran with interesting pharmacological and biological properties. The flavonoids luteolin-7-O-glucoside, apigenin-7-O-glucoside (cosmosiin), luteolin 3′-O-β-d-glucuronide, luteolin, apigenin, cirsimaritin, isokaempferide, penduletin, xanthomicrol, calycopterin and the polyphenol rosmarinic acid were identified among 13 natural populations of the plant by ESI–MS, LC–DAD and LC–DAD–ESI-MS. The plant extracts containing the identified compounds showed significant antioxidant activity, which was correlated with the flavonoid content. Additionally, leaf and stem size and geographical variability among the studied populations were correlated with flavonoid accumulation. Canonical correlation analysis was used to find a relationship between plant dimensions and phytochemical composition, and the plants with the lowest growth indices were found to have the highest levels of methoxylated flavonoids.     

Antioxidant activity and characterization of constituents in copao fruits (Eulychnia acida Phil., Cactaceae) by HPLC–DAD–MS/MSn

Copao (Eulychnia acida Phil., Cactaceae) is an endemic species occurring in arid areas of northern Chile. The fruits are commercialized by peasants within the Elqui and Limari valleys and are appreciated for its acidic and refreshing taste. We now report the total phenolic (TP) and total flavonoid (TF) content, antioxidant activity, phenolic composition and main phenolic distribution in pulp and epicarp of copao fruits from different harvesting places from both valleys. The ascorbic acid content was determined in fresh fruit pulp, epicarp and juice. The phenolic-enriched extract was analyzed for antioxidant effect and composition. Ferulic acid, 9,10-dihydroxy-4,7-megastigmadien-3-one hexoside, isorhamnetin and quercetin glycosides were identified by HPLC–DAD–MS/MS analysis. The main compounds were isolated and fully characterized by NMR techniques. The main phenolic in the samples was isorhamnetin-3-O-[α-rhamnopyranosyl-(1 → 6)-β-glucopyranoside]. The HPLC pattern of the phenolic-enriched extracts of the fruits allows a differentiation of samples from the Elqui and Limari valleys. All fruit extracts and Amberlite-retained fraction from the methanolic extract were devoid of toxicity against human gastric AGS cells and human lung fibroblasts, with IC₅₀ values > 400 μg/mL for AGS and 344 to > 400 μg/mL for fibroblasts, respectively. The compound identification, associated with the antioxidant activity and insignificant cell toxicity, adds relevant information for the possible development of this native fruit into a new crop.     

Characterization of nutritionally important phytoconstituents in minimally processed ready-to-eat baby-leaf vegetables using HPLC–DAD and GC–MS

Ready-to-eat baby-leaf vegetable market has been rapidly growing and offering to consumers convenient and appealing products, rich in health beneficial bioactive compounds. In the present study, the composition of carotenoids, tocopherols, and fatty acids were analyzed in seven baby-leaf vegetables using HPLC–DAD and GC–MS. Among the vegetables, the maximum amount (μg/g FW) of All-E-violaxanthin (42.77), 9′-Z-neoxanthin (22.13), All-E-lutein (69.67), All-E-β-carotene (60.18), total carotenoids (195.21), γ-tocopherol (19.68) and total tocopherol (47.68) were found in Batavian lettuce (Lactuca sativa L. var. Acephala). In all the studied baby-leaf vegetables, α-linolenic acid (ALA, C18:3) was found in highest quantity (44.73–54.39 %) followed by palmitic acid (C16:0) (13.02–19.49 %), and linoleic acid (C18:2) (8.25–21.54 %). Significantly high amount polyunsaturated fatty acids (PUFA) were recorded in Batavian lettuce (74.33 %) and red Romaine (72.72 %), compared to other studied vegetables. In view of health benefits, baby-leaf vegetables contain a low amount of saturated fatty acids and high-mono and PUFA, which can enhance the health benefits of these vegetables. Carotenoids in most of these studied baby-leaf vegetables can be classified as very high. Knowledge of carotenoid, tocopherols and fatty acids composition in different baby-leaf vegetables will be useful to nutritional experts for selection of nutrient-dense plants for food fortification and proper diet recommendation. To our knowledge, this is the first report on fatty acids composition from baby-leaf vegetables.     

Interference-free determination of illegal dyes in sauces and condiments by matrix solid phase dispersion (MSPD) and liquid chromatography (HPLC–DAD)

A fast, simple and effective extraction method based on matrix solid phase dispersion (MSPD) was developed and validated for the simultaneous cleaning-up and quantitative extraction of illegal dyes (sudan I, sudan II, sudan III and sudan IV) from different sauces and condiments. Several parameters as sorbent, cleaning procedure to eliminate carothenoids and other interferences, and solvents for elution were evaluated to find the optimal MSPD conditions. The best results were obtained using a system containing washed sea sand and Florisil as sorbents and sodium sulphate as desiccant; hexane was used as defatted agent and acetonitrile as elution solvent. Quantitative analyses were performed by liquid chromatography (LC) with diode array detection (DAD). The chromatographic separation was performed on a Phenomenex Synergy Polar RP column with isocratic elution using methanol/acetonitrile/water 65/20/15, v/v/v, as the mobile phase at a flow rate of 1.0 mL min⁻¹ and 30 °C of temperature. Under these conditions sudan I–IV recoveries were between 60% and 99% and relative standard deviations ranging from 2.0% to 10.0%. Limits of detection resulted five times lower than the values required by European regulations and were ranged between 0.05 and 0.09 μg g⁻¹. The applicability of this MSPD–DAD method to determine illegal sudan dyes in sauce and condiment samples was demonstrated. This method has potential to be applied using a simple instrumentation present in most analytical laboratories.     

Quantitative analysis of triterpenoids in different parts of Ilex hainanensis, Ilex stewardii and Ilex pubescens using HPLC–ELSD and HPLC–MS and antibacterial activity

An HPLC–ELSD method was first developed for the quantitative analysis of principle triterpenoids in Ilex hainanensis, Ilex stewardii and Ilex pubescens. The established method, with excellent precision, repeatability and recovery, was successfully applied to determine four triterpenoids in 24 samples from different species and medicinal parts of Ilex, and the changing trend was discussed. HPLC–ESI–MSⁿ was used for the identification of constituents in samples. The proposed method was simple, effective and suitable for investigations of these plants. Furthermore, the ethanol extracts from leaves of Ilex species, as well as their main components, were assessed for their antibacterial activities. The results indicated that the extracts of I. hainanensis, I. stewardii and I. pubescens could inhibit the growth of the tested oral pathogens, Streptococcus mutans and Actinomyces viscosu. Particularly, ilexgenin A was the most effective with MIC values of 7.8 and ?3.9 μg/ml, respectively.     

Identification and quantification of major phenolic compounds from mango (Mangifera indica, cv. Ataulfo) fruit by HPLC–DAD–MS/MS-ESI and their individual contribution to the antioxidant activity during ripening

Mango (Mangifera indica L.) is an economically important fruit throughout the world. ‘Ataulfo’ mango, a leading cultivar in Mexico, has the highest content of phenolic compounds among several commercial varieties of mango. However, the individual identification and antioxidant contribution of these phenols during ripening of mango fruit is unknown. Qualitative and quantitative analysis of the major phenolic compounds found in ‘Ataulfo’ mango fruit pulp was conducted in four stages of ripeness, using high-performance liquid chromatography coupled to mass spectrometry. The antioxidant contribution of each of the major phenolic compounds was calculated. The major compounds identified were chlorogenic acid (28–301 mg/100 g DW), gallic acid (94.6–98.7 mg/100 g DW), vanillic acid (16.9–24.4 mg/100 g DW), and protocatechuic acid (0.48–1.1 mg/100 g DW). The antioxidant contribution of the four phenolic acids increased during ripening. Gallic acid accounted for the highest contribution (39% maximum value), followed by chlorogenic acid (21% maximum value). This could indicate that these phenolic compounds may have an important role in the antioxidant metabolism in ‘Ataulfo’ mango fruit during ripening, and promoting health benefits to consumers.     

Simultaneous analysis of thirteen phytohormones in fruits and vegetables by SPE-HPLC–DAD

Food Science and Biotechnology - Determination of phytohormones have attracted increasing attentions in food safety field. In this study, an efficient and quantitative method was developed which...     

A Simple and Selective Analytical Procedure for the Extraction and Quantification of Lutein from Tomato By-Products by HPLC–DAD

Lutein, a yellow dihydroxylated carotenoid, is present in many dietary supplements due to its biological properties. Currently, lutein is extracted from marigold flowers by expensive and time-consuming processes. Since tomatoes contain significant levels of lutein, in this study we have examined the feasibility of using tomato by-products as an alternative, low-cost source of this carotenoid. The determination of this carotenoid was performed by high-performance liquid chromatography–diode array detection, after selective extraction from tomato waste product samples. Lutein levels ranged from 9.9 to 10.5 μg/g dry weight. Tomato waste products may be indicated as an alternative commercial source of lutein for food fortification and/or dietary supplements.     

Identification and quantification of constituents of Gardenia jasminoides Ellis (Zhizi) by HPLC-DAD–ESI–MS

A simple, rapid and specific HPLC method was carried out for the analysis of characteristic constituents in Gardenia jasminoides Ellis (Zhizi), namely iridoids, caffeoyl quinic acid derivatives and crocins. The separation was successfully obtained using a C₁₈ column by gradient elution with mixtures of methanol and water as mobile phases; detection wavelength was set at 240 nm for iridoid glycosides, 315 nm for quinic acid derivatives and 438 nm for crocins.     

De-oiled rapeseed and a protein isolate: characterization of sinapic acid derivatives by HPLC–DAD and LC–MS

De-oiled rapeseed is a rich source of proteins and phenolic compounds. The phenolic compounds, namely sinapic acid derivatives (SAD), could occur as free sinapic acid, esterified (as sinapine, the choline ester of sinapic acid) and decarboxylated (as canolol) forms. Rapeseed protein preparations containing very low phenolic compounds have been the focus of our ongoing research. A precipitated rapeseed protein isolate is investigated for SAD such as sinapine, sinapoyl glucose, canolol using HPLC–DAD and LC–MS. Profile of the phenolic compounds of de-oiled rapeseed, press cakes and the precipitated protein isolate are compared. HPLC–DAD analysis indicated SAD; particularly sinapine is the main phenolic compound of all the substrates. The protein derivation process did not remarkably alter the profile of the investigated protein isolate.     

HPLC–MS identification and quantification of flavonol glycosides in 28 wild and cultivated berry species

Berries and red fruits are rich dietary sources of polyphenols with reported health benefits. More than 50 different flavonols (glycosides of quercetin, myricetin, kaempferol, isorhamnetin, syringetin and laricitrin) have been detected and quantified with HPLC–MSⁿ in fruits of blueberry, bilberry, cranberry, lingonberry, eastern shadbush, Japanese wineberry, black mulberry, chokeberry, red, black and white currants, jostaberry, red and white gooseberry, hardy kiwifruit, goji berry, rowan, dog rose, Chinese and midland hawthorn, wild and cultivated species of blackberry, raspberry, strawberry and elderberry. The phenolic constituents and contents varied considerably among the analyzed berry species. Elderberry contained the highest amount of total flavonols (450–568 mg kg⁻¹ FW), followed by berry species, containing more than 200 mg kg⁻¹ FW of total: chokeberry (267 mg kg⁻¹), eastern shadbush (261 mg kg⁻¹), wild grown blackberry (260 mg kg⁻¹), rowanberry (232 mg kg⁻¹), american cranberry (213 mg kg⁻¹) and blackcurrants (204 mg kg⁻¹). Strawberry (10.5 mg kg⁻¹) and white currants (4.5 mg kg⁻¹) contained the lowest amount of total flavonols. Quercetins represent the highest percentage (46–100%) among flavonols in most analyzed berries. In wild strawberry and gooseberry the prevailing flavonols belong to the group of isorhamnetins (50–62%) and kaempferols, which represent the major part of flavonols in currants (49–66%). Myricetin glycosides could only be detected in chokeberry, rowanberry and species from the Grossulariaceae, and Adoxaceae family and Vaccinium genus. Wild strawberry and blackberry contained from 3- to 5-fold higher total flavonols than the cultivated one.     

Utilisation of orange peel in the production of α-terpineol by Penicillium digitatum (NRRL 1202)

The use of orange peel oil in the biotransformation of d-limonene was investigated. The physicochemical properties of cold-pressed orange peel oil, used in this investigation were determined to define its identity. The chemical composition of orange peel oil was determined by using GC/MS. Monoterpene compounds amounted to 98.0%, followed by aldehdyde components 1.09%. The main component of orange peel oil was d-limonene, which represented 96.1%, of the total content. A strain of Penicillium digitatum NRRL 1202 was used to carry out the biotransformation of d-limonene to α-terpineol. Two different media, malt yeast broth (MYB) and malt extract broth (MEB) were used. It was found that the highest bioconversion of d-limonene into α-terpineol was obtained by using MYB medium (pH 6.1).