Ibrahim M. Abu-Reidah

HPLC-DAD-ESI-MS/MS screening of bioactive components from Rhus coriaria L. (Sumac) fruits

Rhus coriaria L. (sumac) is an important crop widely used in the Mediterranean basin as a food spice, and also in folk medicine, due to its health-promoting properties. Phytochemicals present in plant foods are in part responsible for these consequent health benefits. Nevertheless, detailed information on these bioactive compounds is still scarce. Therefore, the present work was aimed at investigating the phytochemical components of sumac fruit epicarp using HPLC-DAD-ESI-MS/MS in two different ionisation modes. The proposed method provided tentative identification of 211 phenolic and other phyto-constituents, most of which have not been described so far in R. coriaria fruits. More than 180 phytochemicals (tannins, (iso)flavonoids, terpenoids, etc.) are reported herein in sumac fruits for the first time. The obtained results highlight the importance of R. coriaria as a promising source of functional ingredients, and boost its potential use in the food and nutraceutical industries.

Reversed-phase ultra-high-performance liquid chromatography coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry as a powerful tool for metabolic profiling of vegetables: Lactuca sativa as an example of its application

Lettuce (Lactuca sativa), a leafy vegetal widely consumed worldwide, fresh cut or minimally processed, constitutes a major dietary source of natural antioxidants and bioactive compounds. In this study, reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry (ESI-QTOF-MS) was applied for the comprehensive profiling of polar and semi-polar metabolites from three lettuce cultivars (baby, romaine, and iceberg). The UHPLC systems allowed the use of a small-particle-size C18 column (1.8 μm), with very fine resolution for the separation of up to seven isomers, and the QTOF mass analyzer enabled sensitive detection with high mass resolution and accuracy in full scan. Thus, a total of 171 compounds were tentatively identified by matching their accurate mass signals and suggested molecular formula with those previously reported in family Asteraceae. Afterwards, their structures were also corroborated by the MS/MS data provided by the QTOF analyzer. Well-known amino acids, organic acids, sesquiterpene lactones, phenolic acids and flavonoids were characterized, e.g. lactucin, lactucopicrin, caftaric acid, chlorogenic acid, caffeoylmalic acid, chicoric acid, isochlorogenic acid A, luteolin, and quercetin glycosides. For this plant species, this is the first available report of several isomeric forms of the latter polyphenols and other types of components such as nucleosides, peptides, and tryptophan-derived alkaloids. Remarkably, 10 novel structures formed by the conjugation of known amino acids and sesquiterpene lactones were also proposed. Thus, the methodology applied is a useful option to develop an exhaustive metabolic profiling of plants that helps to explain their potential biological activities and folk uses.

Extensive characterisation of bioactive phenolic constituents from globe artichoke (Cynara scolymus L.) by HPLC–DAD-ESI-QTOF-MS

The aim of this work was to characterise the phenolic compounds in artichoke (hearts) by using HPLC coupled to DAD-ESI-QTOF-MS, which proved useful in characterising 61 phenolic and other polar compounds. Notably, of the 61 compounds characterised, 34 new phenolic compounds with their isomers have been tentatively characterised in artichoke for the first time, namely: 3 hydroxybenzoic acids, 17 hydroxycinnamic acids, 4 lignans, 7 flavones, 2 flavonols, and 1 phenol derivative. Moreover, a total of 28 isomers of previously described phenolics have also been detected. The data compiled from the qualitative polyphenol characterisation indicate that the artichoke extract analysed (Blanca de Tudela variety) could be regarded as a bioactive functional food and also as a promising source of antioxidant phenolic compounds.

Phytochemical Characterisation of Green Beans (Phaseolus vulgaris L.) by Using High-performance Liquid Chromatography Coupled with Time-of-flight Mass Spectrometry

INTRODUCTION Although green beans (Phaseolus vulgaris L.) constitute a major agro-industrial crop worldwide and involve many bean varieties, the phytochemical composition and how this fluctuates among varieties is not well known. OBJECTIVE The purpose of this work was to conduct a comprehensive characterisation of the phytochemical compounds found in three varieties of green bean. METHODOLOGY Hydromethanol extracts from green beans were analysed by high-performance liquid chromatography (HPLC) coupled with electrospray time-of-flight mass spectrometry (ESI-TOF-MS) in order to characterise phytochemical compounds from different varieties of P. vulgaris L. The compounds were characterised based on interpreting their mass spectrum provided by the TOF-MS as well as by comparison with information from the literature (some compounds have been described previously in Fabaceae). RESULTS In this work, 72 phytochemical compounds were tentatively characterised by HPLC-ESI-TOF-MS. These compounds were classified as, 10 phenolic acids, 59 flavonoids, two lignans and an iridoid. Notably, out of the 72 compounds, 54 are new and their isomers have been characterised for the first time in green beans. CONCLUSION The phytochemical composition of three different varieties of P. vulgaris L have been characterised using HPLC-ESI-TOF-MS. A total of 72 phytochemical compounds were characterised, 54 being reported in green beans for the first time. Among these were the main flavonoids detected. These results highlight the influence that variety can exert on the quality of phytochemicals. Given that new phytochemical compounds have been characterised, this study offers a useful approach for improving and updating the food-composition tables.

UHPLC-ESI-QTOF-MS-based metabolic profiling of Vicia faba L. (Fabaceae) seeds as a key strategy for characterization in foodomics

Vicia faba (Fabaceae) is a popular food in many countries and a good source of nutrients. However, little is known about its phytochemical composition, specially referring to phenolic compounds. In the present work, the dietary metabolites from a hydro‐methanolic extract of V. faba seeds were thoroughly characterized by a nontargeted analytical approach based on reversed‐phase ultra‐HPLC (UHPLC) coupled to QTOF‐MS. A total of 155 primary and secondary metabolites of various structural types were characterized: carbohydrates, amino acids, organic acids, alkaloids, terpenoids, jasmonates, and, mainly, polyphenols. Among the latter group, 73 compounds were characterized for the first time in this legume. In addition, 24 new structures, belonging to jasmonates and glycosylated N‐containing compounds, were also proposed. Thus, this methodology could be implemented in foodomics as a characterization strategy to complement the knowledge of the phytochemical composition of vegetables.

Tentative Characterisation of Iridoids, Phenylethanoid Glycosides and Flavonoid Derivatives from Globularia alypum L. (Globulariaceae) Leaves by LC‐ESI‐QTOF‐MS

INTRODUCTION Globularia alypum L., belonging to the Globulariaceae family, is a perennial wild shrub found throughout the Mediterranean area, Europe, and Africa. This plant is widely used to treat many diseases, but no previous work on the phytochemical composition of the Algerian G. alypum species has yet been reported. OBJECTIVE To investigate the phytoconstituents of the methanolic extract of G. alypum using an LC-ESI-QTOF-MS method. METHODS Ground air-dried leaves of G. alypum were macerated with methanol at room temperature for 24 h. The supernatant was filtered and concentrated to dryness under reduced pressure in a rotary evaporator, and extracts were recovered with methanol and filtered. Afterwards, the G. alypum extract was injected into the LC-ESI-QTOF-MS system. RESULTS The combined LC-MS/MS led to the tentative characterisation of 63 phytochemicals. In this work, a large number of compounds have been characterised in the leaf-extract analysis of this plant. Among others, 24 iridoids and secoiridoids were found, of which nine compounds have not previously been recorded in G. alypum. Also, nine unusual phenylethanoid glycosides were characterised for the first time in this species. CONCLUSION The method used has proved to be a valued tool for the characterisation of a wide range of compounds from G. alypum leaves. This work constitutes a detailed investigation of the chemical composition of G. alypum leaves, which are widely used in different traditional systems of medicine.

In vitro antioxidant and antitumor activities of six selected plants used in the Traditional Arabic Palestinian herbal medicine

Abstract Context: Despite several pharmacological applications of the medicinal plants in the Traditional Arabic Palestinian Herbal Medicine in Palestine (TAPHM), studies on their antioxidant properties are still scarce. Objective: This work evaluates the antioxidant and antitumor activities of the ethanol extracts from different parts of six plants: [Arum palaestinum Boiss (Araceae), Urtica pilulifera L. (Urticaceae), Coridothymus capitatus (L.) Reichb (Lamiaceae), Majorana syriaca (L.) Rafin. (Lamiaceae), Teucrium creticum L. (Lamiaceae), and Teucrium capitatum L. (Lamiaceae)] used in the TAPHM. Materials and methods: The antioxidant activity was evaluated for the ethanol extracts by DPPH and β-carotene–linoleic acid assays together with total contents of phenols and flavonoids. For the anti-carcinogenic evaluation, the extracts were tested for the ability to inhibit the proliferation of breast cancer cells (MCF-7) using the MTT reduction assay. Results: Among the extracts, the U. pilulifera had the highest amount of total phenolics, possessing the second highest total flavonoids. It also showed a maximum cytotoxic activity (IC50 = 63 µg/ml), followed by C. capitatus, and A. palaestinum. Otherwise, the extract of T. creticum was demonstrated to be an efficient scavenger of O2 (IC50 = 83 µg/ml), followed by M. syriaca, C. capitatus, T. capitatum, A. palaestinum, and U. pilulifera. Discussion and conclusion: The results suggest that the investigated plants have shown varied antioxidant capacities which were strongly correlated with their contents of phenolics. Accordingly, this study proposes that the therapeutic benefit of these plants can be, at least in part, attributed to its potential inhibition of oxidative processes.

UHPLC/MS2-based approach for the comprehensive metabolite profiling of bean (Vicia faba L.) by-products: A promising source of bioactive constituents

Today, by-products generated from the agro-industrial practices are considered a key source of bioactive and functional components, that can be used for their nutritional and added value properties. New aspects concerning the use of these wastes as by-products in food production additives or supplements with high nutritional and medicinal value have gained substantial interest, due to their possession of economically high-value products. In this sense, the present study describes a thorough characterization of phytochemical compounds from hydro-methanolic extract of broad beans testa by using ultra-high performance liquid chromatography (UHPLC) hyphenated with quadrupole-time-of-flight tandem mass spectrometry (QTOF-MS). The proposed analytical technique provides tentative characterization of 134 phenolic and other phytochemical compounds in the Vicia faba extract, most of which have not been described so far in broad beans. Thus, >85 phytochemicals (Amino acids, phenolic acids, flavonoids, lignans, and terpenoids derivatives) are being reported herein in broad beans pods for the first time. The characterization process was carried out using MS and MS2 data provided by the ESI-qTOF-MS, along with the use of the relevant literature based on the same botanical family. The data obtained demonstrates that the agro-industrial by-product could potentially be utilized as a promising source of bioactive ingredients to design new functional foods and nutraceuticals with a valuable future market. Furthermore, the obtained data may form a basis for future quantitative and bioavailability studies, which will be the next step in this present work.

Phenolic composition profiling of different edible parts and by-products of date palm (Phoenix dactylifera L.) by using HPLC-DAD-ESI/MSn

Fruits and vegetables are an important source of dietary antioxidants and epidemiological studies show that their regular intake in the diet may decrease the risk of several chronic diseases. Phoenix dactylifera L. (date palm or dates) is an important crop, widely used in the Arabian region and in other parts of the world as a food and also in folk medicine, due to its health-promoting properties. Antioxidant phytochemicals present in plant foods are partly responsible for such health benefits. The antioxidants present in dates are mainly phenolics, like flavonoids and phenolic acids. The fruits of dates have been widely studied with regard to their phenolic composition. However, few studies are available in the bibliography regarding other, non-edible parts of the date palm tree. In this context, in the present work the phenolic components of different parts of P. dactylifera (cv. Medjool or Mejhool) - namely, fruit pulp and skin, fronds (leaves), clusters, and pollen - have been investigated using HPLC-DAD-ESI/MSn in the negative ionization mode. The overall analysis of the phenolic compounds revealed that there was a qualitative similarity among the different dates parts analyzed. The method used provided tentative identification of 52 compounds: mainly flavonoid glycosides of quercetin, luteolin, apigenin, chrysoeriol, kaempferol, isorhamnetin, 3-methyl-isorhamnetin, sulfates, and malonyl derivatives. In the present work, more than 30 phenolic derivatives are described for the first time in dates. To the best of our knowledge, kaempferol glycosides and malonyl derivatives have not been described previously in P. dactylifera. The results highlight the importance of P. dactylifera L. as a promising source of functional ingredients and boost its potential use in the food and nutraceutical industries. The MS data, MSn fragmentation pattern, and UV information obtained have been of great help in the interpretation of the compounds detected and in their structural identification.

Vasculoprotective Effects of Pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.), one of the oldest known edible fruits, is nowadays broadly consumed throughout the world. Its fruits and seeds as well as other anatomical compartments (e.g., flowers and leaves) are rich in numerous bioactive compounds and therefore, the scientific interest in this plant has been constantly growing in recent years. It has been shown that pomegranate and its extracts exhibit potent antioxidative, antimicrobial, and anticarcinogenic properties. The present review summarizes some recent studies on pomegranate, highlighting mainly its vasculoprotective role attributed to the presence of hydrolyzable tannins ellagitannins and ellagic acid, as well as other compounds (e.g., anthocyanins and flavonoids). These in vitro and in vivo studies showed that substances derived from pomegranate reduce oxidative stress and platelet aggregation, diminish lipid uptake by macrophages, positively influence endothelial cell function, and are involved in blood pressure regulation. Clinical studies demonstrated that daily intake of pomegranate juice lessens hypertension and attenuates atherosclerosis in humans. Altogether, the reviewed studies point out the potential benefits of a broader use of pomegranate and its constituents as dietary supplements or as adjuvants in therapy of vascular diseases, such as hypertension, coronary artery disease, and peripheral artery disease.