Determination of flavone, flavonol, and flavanone aglycones by negative ion liquid chromatography electrospray ion trap mass spectrometry

Screening for CYP3A4 inhibition and induction coupled to parallel artificial membrane permeability assay (PAMPA) for prediction of botanical-drug interactions: The case of açaí and maca

BACKGROUND

The consumption of botanical dietary supplements (BDS) is a common practice among the US population. However, the potential for botanical-drug interactions exists, and their mechanisms have not been thoroughly studied. CYP3A4 is an important enzyme that contributes to the metabolism of about 60% of clinically used drugs.

PURPOSE

To investigate the potential for botanical-drug interactions of Lepidium meyenii Walpers (maca) root and Euterpe oleracea Mart. (açaí) berries, two commonly used BDS, when co-administered with CYP3A4-metabolized drugs.

METHODS

In an attempt to decrease the general discrepancy between in vivo and in vitro studies, the absorption profiles, particularly for passive diffusion, of plant extracts were investigated. Specifically, the parallel artificial membrane permeability assay (PAMPA) model was utilized to simulate intestinal filtration of passively diffused constituents of açaí and maca extracts. These were subsequently screened for in vitro liver CYP3A4 inhibition and induction. In the inhibition assay, midazolam was used as the probe substrate on genotyped human liver microsomes (CYP3A5 null), and the production of its 1'-substituted metabolite when co-cultured with extract treatments was monitored. In the induction assay, extract treatments were applied to human primary hepatocytes, and quantitative PCR analysis was performed to determine CYP3A4 mRNA expression.

RESULTS

Passively diffused constituents of the methanol açaí extract (IC₅₀ of 28.03 µg/µl) demonstrated the highest inhibition potential, and, at 1.5 µg/µl, induced significant changes in CYP3A4 gene expression. The composition of this extract was further investigated using the chemometric tool Mass Profiler Professional (MPP) on liquid chromatography-mass spectroscopy (LC-MS) data. Subsequently, five compounds of interest characterized by high abundance or high permeability were extracted for further study. This included efforts in effective passive permeability determination and structural elucidation by tandem mass spectrometry (MS/MS).

CONCLUSION

The passively absorbable portion of a methanol açaí extract exhibited inhibition and induction effects on CYP3A4 suggesting the potential to produce botanical-drug interactions.

Antioxidant activity and characterization of flavonoids and phenolic acids of Ammoides atlantica by RP-UHPLC-ESI-QTOF-MSn

In this study, phytochemical profiling of hydro-alcoholic extract of Ammoides atlantica aerial parts has been carried out using RP-UHPLC-ESI-QTOF-MS in negative ionization mode Chemical characterization was established according to the MS and MS/MS spectra. A total of 66 chemical compounds were detected. Among these, 45 compounds were identified: hydroxycinnamic acid and derivatives (26), hydroxybenzoic acids (4), flavones (11), flavonols (3), and a lignan. Total phenolics (371.57 mg/g) and total flavonoids (41.02 mg/g) contents were also determined. Moreover, the antioxidant activity of A. atlantica extract was also studied by six methods: DPPH (IC₅₀: 23.31 µg/mL), ABTS⁺ (IC₅₀: 11.31 µg/mL), O₂^- DMSO alkaline (IC₅₀: 3.19 µg/mL), ferrous ions chelating assays (IC₅₀: 102.35 µg/mL), reducing power (A_0.50: 92.70 µg/mL) and CUPRAC (A_0.50: 13.56 µg/mL) assays. These results suggest that the antioxidant activity of the hydroalcoholic extract was comparable to common antioxidant additives in most of the tests, representing a good alternative.

Green Tea Seed Oil Suppressed Aβ1⁻42-Induced Behavioral and Cognitive Deficit via the Aβ-Related Akt Pathway

The aim of this study was to investigate the availability of seeds, one of the byproducts of green tea, and evaluate the physiological activity of seed oil. The ameliorating effect of green tea seed oil (GTO) was evaluated on H₂O₂-induced PC12 cells and amyloid beta (Aβ)_1–42-induced ICR mice. GTO showed improvement of cell viability and reduced reactive oxygen species (ROS) production in H₂O₂-induced PC12 cells by conducting the 2′,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2′,7′-dichlorofluorescein diacetate (DCF-DA) analysis. Also, administration of GTO (50 and 100 mg/kg body weight) presented protective effects on behavioral and memory dysfunction by conducting Y-maze, passive avoidance, and Morris water maze tests in Aβ-induced ICR mice. GTO protected the antioxidant system by reducing malondialdehyde (MDA) levels, and by increasing superoxide dismutase (SOD) and reducing glutathione (GSH) contents. It significantly regulated the cholinergic system of acetylcholine (ACh) contents, acetylcholinesterase (AChE) activities, and AChE expression. Also, mitochondrial function was improved through the reduced production of ROS and damage of mitochondrial membrane potential (MMP) by regulating the Aβ-related c-Jun N-terminal kinase (JNK)/protein kinase B (Akt) and Akt/apoptosis pathways. This study suggested that GTO may have an ameliorating effect on cognitive dysfunction and neurotoxicity through various physiological activities.

Flavonoids from Rosa Damascena Mill

A new flavanone glycoside, butin 4′-O-(2″-O-β-D-apiofuranosyl)-β-D-glucopyranoside (1), together with liquiritin (2), liquiritin apioside (3), isoliquiritn apioside (4), davidioside (5), quercetin (6), kaempferol (7), kaempferol 3-O-β-D-glucopyranoside (8) and kaempferol 3-O-α-L-arabinofuranoside (9) were isolated from the marc of Rosa damascena flowers after industrial distillation of essential oil. This is the first report of the occurrence of compounds 2, 3, 4 and 5 in R. damascena. The structures of the isolated constituents were established on the basis of spectroscopic {UV, IR, 1D, 2D NMR (DEPT, HMQC, HMBC and COSY)}, spectrometric (ESI-QTOF-MS), and chemical evidence.

Insight of Stability of Procyanidins in Free and Liposomal Form under an in Vitro Digestion Model: Study of Bioaccessibility, Kinetic Release Profile, Degradation, and Antioxidant Activity

Small unilamellar and multilayered liposomes loaded with polymeric (epi)catechins up to pentamers were produced. The bioaccessibility, kinetic release profile, and degradation under in vitro gastrointestinal conditions were monitored by UHPLC-DAD-QTOF-MS/MS. The results show that all of the procyanidins underwent depolymerization and epimerization into small molecular oligomers and mainly to (epi)catechin subunits. Moreover, all of the liposome formulations presented higher bioaccessibility and antioxidant activity in comparison to their respective counterparts in non-encapsulated form. Similar results were obtained with procyanidins from cocoa extract-loaded liposomes. Namely, the bioaccessibility of dimer, trimer, and tetramer fractions from cocoa-loaded liposomes were 4.5-, 2.1-, and 9.3-fold higher than those from the non-encapsulated cocoa extract. Overall, the procyanidin release profile was dependent on their chemical structure and physicochemical interaction with the lipid carrier. These results confirmed that liposomes are efficient carriers to stabilize and transport procyanidins with the aim of enhancing their bioaccessibility at a controlled release rate.

Chemical Characterization of Leaves, Male and Female Flowers from Spontaneous Cannabis (Cannabis sativa L.) Growing in Hungary

Spontaneous forms of hemp (Cannabis sativa L., often reported as Cannabis sativa var. spontanea Vavilov) with a low content of psychoactive cannabinoids can be considered as a valuable source of other phytoconstituents to be used in nutraceuticals or for their health promoting properties. Chemical data on this hemp variety are rather scarce. In this article, we report a comprehensive phytochemical characterization of leaves, male and female inflorescences of C. sativa growing wild in Hungary. For the purpose, the essential oil along with polar extracts were analyzed using GC/MS, NMR and LC-DAD-MS techniques, respectively. The results indicated that female inflorescence essential oil contains high amounts of the CB2 agonists, (E)-caryophyllene (28.3 %) and cannabidiol (CBD; 24.9 %), whereas leaves and male inflorescence essential oils contained lower amounts of both compounds. HPLC/MS allowed to quantify cannabidiol (CBD) and cannabidiolic acid (CBD-A) in the ethyl acetate extracts from leaves, male and female inflorescences; they were 0.3, 0.8 and 0.9 %, and 0.2, 0.3 and 0.4 %, respectively. Flavonoids of this spontaneous form of hemp were formed by C-glycosides and glucuronic acids of kaempferol and apigenin with a total content of 3.8, 6.1 and 7.8 mg/g in methanolic extracts from leaves, male and female inflorescences, respectively. Based on these results, spontaneous C. sativa may represent an important source of CB₂ agonists and bioflavonoids to be used in nutraceuticals, cosmetics and pharmaceuticals.

Pharmacokinetics, Tissue Distribution, Metabolism, and Excretion of Naringin in Aged Rats

Aging is an inevitable biological process characterized by the loss of functional capacity and associated with changes in all phases of pharmacokinetic processes. Naringin, a dietary flavanone glycoside, has been proved to be beneficial for the treatment of multiple age-associated chronic diseases. To date, the pharmacokinetic processes of naringin in aged individuals are still unknown. Thus, a rapid resolution liquid chromatography tandem triple quadrupole mass spectrometry (RRLC-QQQ-MS/MS) method was established for the determination of naringin and its metabolite naringenin in rat plasma, urine, feces, and tissue homogenate. The pharmacokinetic parameters were calculated and a higher exposure of naringin and naringenin were observed in aged rats. Naringin and naringenin were mostly distributed in gastrointestinal tract, liver, kidney, lung, and trachea. Furthermore, a total of 39 flavonoid metabolites (mainly glucuronides and sulfates) and 46 microbial-derived phenolic catabolites were screened with ultra-fast liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS). Naringenin, hippuric acid, and 3-(4'-hydroxyphenyl)propionic acid were predominated metabolites. This study systemically investigated the pharmacokinetics, tissue distribution, metabolism, and excretion of naringin in aged rats, revealing age- and gender-related changes in the in vivo behavior of naringin. These results would be helpful for the interpretation of pharmacokinetics and pharmacodynamics of naringin in aged population.

Nutritional Composition, Anti-Diabetic Properties and Identification of Active Compounds Using UHPLC-ESI-Orbitrap-MS/MS in Mangifera odorata L. Peel and Seed Kernel

Mangifera odorata fruit, the hybrid forms between M. indica (mango) and M. foetida (bacang), has been shown to exhibit potential antioxidant activity, and the fruit waste could demonstrate functional and nutritional potential. In the present study, the nutritional composition (proximate, sugars, vitamins and minerals analyses), the anti-diabetic activities and phytochemical profile of M. odorata peel and seed kernel were investigated for the first time. The results indicated that seed kernel rich in fat, protein, carbohydrate, and ash while peel contained significantly greater amount of fiber, minerals, β-Carotene and ascorbic acid compared to seed kernel. The samples were then extracted using different solvents (acetone, ethanol, methanol at 60%, v/v and pure deionized water) and their anti-diabetic activities (α-amylase and α-glucosidase inhibition assay) were determined. Seed kernel had the lowest IC50 values for α-amylase and α-glucosidase inhibition assay in 60% ethanol and 60% acetone, respectively. Due to the toxic effect and high volatility of acetone, the ethanolic extracts of samples were further analyses for their phytochemical profile using high performance liquid chromatography-mass spectrometry (LC-MS) and ultra-high-performance liquid chromatography electrospray ionization orbitrap tandem mass spectrometry (UHPLC-ESI-Orbitrap-MS/MS). The most abundant compounds identified were phenolic acid, ellagic acid, and flavonoid. These findings suggest that M. odorata fruit wastes, especially the seed kernel possesses promising ability to be used as functional ingredient in the food industry.

Chestnut (Castanea sativa Miller.) Burs Extracts and Functional Compounds: UHPLC-UV-HRMS Profiling, Antioxidant Activity, and Inhibitory Effects on Phytopathogenic Fungi

Chestnut (Castanea sativa Miller.) burs (CSB) represent a solid waste produced during the edible fruit harvesting. Their usual disposal in the field increases the environmental and economic impact of the agricultural process. HPLC-UV-HRMS profiling revealed that CSB organic and aqueous extracts (CSB-M, CSB-H, CSB-A) contain several hydrolyzable tannins, mainly ellagitannins, and glycoside flavonols. Ellagic acid (EA) and chestanin are predominant components (5–79 and 1–13 mg/g dry extract, respectively). NMR analysis confirmed the chemical structures of the major constituents from CSB-M. The extracts displayed a significant scavenging activity against DPPH^• (EC₅₀ 12.64–24.94 µg/mL) and ABTS^•+ radicals (TEAC value 2.71–3.52 mM Trolox/mg extract). They were effective in inhibiting the mycelial growth (EC₅₀ 6.04–15.51 mg/mL) and spore germination (EC₅₀ 2.22–11.17 mg/mL) of Alternaria alternata and Fusarium solani. At the highest concentration, CSB-M was also active against Botrytis cinerea both in mycelium and spore form (EC₅₀ 64.98 and 16.33 mg/mL). The EA contributed to the antifungal activity of extracts (EC₅₀ on spore germination 13.33–112.64 µg/mL). Our results can support the upgrading of chestnut burs from agricultural wastes to a resource of natural fungicides for managing fruit and vegetable diseases.

Variation in Ceratonia siliqua pod metabolome in context of its different geographical origin, ripening stage and roasting process

Carob is a legume tree of a considerable commercial importance for the flavor and sweet industry. In this context, it is cultivated mostly for its pods, which are known for their nutritive value and multiple health benefits. However, metabolite patterns, underlying these properties are still mostly uncharacterized. In this study, the role of geographical origin, ontogenetic changes and thermal processing on the Ceratonia siliqua pod metabolome was assessed by mass spectrometry (MS)-based metabolomics. Thereby, a total of 70 fruits primary metabolites, represented mainly by carbohydrates, organic and amino acids were detected. Analysis of secondary bioactive metabolites assessed by ultra-high-performance liquid chromatography-electrospray ionization high resolution mass spectrometry (UHPLC-ESI-HR-MS) revealed in total 83 signals. The major signals, most significantly contributing in discrimination of C. siliqua specimens were assigned to tannins and flavonoids. PCA models derived from either UHPLC-MS or GC-MS proved to be powerful tools for discrimination of C. siliqua specimens.

Systematically Characterizing Chemical Profile and Potential Mechanisms of Qingre Lidan Decoction Acting on Cholelithiasis by Integrating UHPLC-QTOF-MS and Network Target Analysis

Qingre Lidan Decoction (QRLDD), a classic precompounded prescription, is widely used as an effective treatment for cholelithiasis clinically. However, its chemical profile and mechanism have not been characterized and elucidated. In the present study, a rapid, sensitive, and reliable ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established for comprehensively identifying the major constituents in QRLDD. Furthermore, a network pharmacology strategy based on the chemical profile was applied to clarify the synergetic mechanism. A total of 72 compounds containing flavonoids, terpenes, phenolic acid, anthraquinones, phenethylalchohol glycosides, and other miscellaneous compounds were identified, respectively. 410 disease genes, 432 compound targets, and 71 related pathways based on cholelithiasis-related and compound-related targets databases as well as related pathways predicted by the Kyoto Encyclopedia of Genes and Genomes database were achieved. Among these pathways and genes, pathway in cancer and MAPK signaling pathway may play an important role in the development of cholelithiasis. EGFR may be a crucial target in the conversion of gallstones to gallbladder carcinoma. Regulation of PRKCB/RAF1/MAP2K1/MAPK1 is associated with cell proliferation and differentiation. Thus, the fingerprint coupled with network pharmacology analysis could contribute to simplifying the complex system and providing directions for further research of QRLDD.

HPLC-DAD-ESI-Q-TOF-MS/MS profiling of Verbascum ovalifolium Donn ex Sims and evaluation of its antioxidant and cytogenotoxic activities

INTRODUCTION

Plant species of Verbascum genus have been intensively investigated in the last decades but most studies focused on evaluation of their biological activities; there are only few studies dealing with their chemical characterisation.

OBJECTIVE

Detailed investigation of the qualitative and quantitative chemical composition, antioxidant and cytogenotoxic activities of a previously non-studied Verbascum species (V. ovalifolium Donn ex Sims).

METHODS

Qualitative analysis of secondary metabolites was performed by HPLC-DAD-ESI-Q-TOF-MS/MS, whereas quantitative data were obtained through HPLC-DAD. Antioxidant activity was evaluated using in vitro assays; cytotoxic and genotoxic effects were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) and comet assays, respectively.

RESULTS

More than 50 secondary bioactive metabolites belonging to various classes (iridoids, phenylethanoids, flavonoids, phenolic acids) were detected in the methanolic extract of V. ovalifolium and its fractions. The fragmentation pathways of acylated catalpol-type iridoid diglycosides are thoughtfully described herein. The extracts showed good free radical scavenging and ferric ion reducing properties correlated with phenolic, flavonoid, chlorogenic acid and verbascoside contents. Moreover, 24 h treatment of SK-MEL-2 cells with V. ovalifolium extracts produced significant changes in terms of tumour cell viability. The crude extract and the ethyl acetate fraction showed no important signs of cytogenotoxicity in non-tumour cells.

CONCLUSION

The performed phytochemical and biological analyses contribute to the preclinical knowledge about V. ovalifolium and they could help exploiting it in novel herbal medicinal products.

Beyond the wall: High-throughput quantification of plant soluble and cell-wall bound phenolics by liquid chromatography tandem mass spectrometry

Plants accumulate several thousand of phenolic compounds, including lignins and flavonoids, which are mainly synthesized through the phenylpropanoid pathway, and play important roles in plant growth and adaptation. A novel high-throughput ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was established to quantify the levels of 19 flavonoids and 15 other phenolic compounds, including acids, aldehydes, and alcohols. The chromatographic separation was performed in 10 min, allowing for the resolution of isomers such as 3-, 4-, and 5-chlorogenic acids, 4-hydroxybenzoic and salicylic acids, isoorientin and orientin, and luteolin and kaempferol. The linearity range for each compound was found to be in the low fmol to the high pmol. Furthermore, this UHPLC-MS/MS approach was shown to be very sensitive with limits of detection between 1.5 amol to 300 fmol, and limits of quantification between 5 amol to 1000 fmol. Extracts from maize seedlings were used to assess the robustness of the method in terms of recovery efficiency, matrix effect, and accuracy. The biological matrix did not suppress the signal for 32 out of the 34 metabolites under investigation. Additionally, the majority of the analytes were recovered from the biological samples with an efficiency above 75%. All flavonoids and other phenolic compounds had an intra- and inter-day accuracy within a ±20% range, except for coniferyl alcohol and vanillic acid. Finally, the quantification of flavonoids, free and cell wall-bound phenolics in seedlings from two maize lines with contrasting phenolic content was successfully achieved using this methodology.

In Vitro Investigation of Potential Anti-Diabetic Activity of the Corm Extract of Hypoxis Argentea Harv. Ex Baker

The corms of Hypoxis argentea are widely used as a traditional remedy for diabetes mellitus in South Africa. In this study, we investigated the effects of non-toxic concentrations (12.5-100 μg mL-1) of the aqueous extract of H. argentea (HAA) corms on glucose uptake, pancreatic beta cell proliferation, and adipocyte differentiation. HAA stimulated glucose uptake in HepG2 cells up to 19.6 % and 17.0 % in L6 myotubes. Live-cell imaging microscopy revealed significant increases (p < 0.001) in total INS-1 cell numbers exposed to HAA, although no effect was observed on adipogenesis in 3T3-L1 pre-adipocytes. HAA produced weak to moderate inhibition of porcine pancreatic α-amylase, α-glucosidase, porcine pancreatic lipase, dipeptidyl peptidase IV (DPP IV) activities, as well as protein glycation. Our results suggest that the acclaimed anti-diabetic effects of H. argentea could be mediated by its promotion of glucose utilization and preservation of pancreatic beta cell populations while preventing fat accumulation in adipocytes.

Vasodilator and hypotensive effects of pure compounds and hydroalcoholic extract of Xenophyllum poposum (Phil) V.A Funk (Compositae) on rats

BACKGROUND

Xenophyllum poposum is an endemic species of the Andes Cordillera, popularly known as Popusa. Popusa is widely used by mountain communities as a folk medicine to treat altitude sickness and hypertension.

PURPOSE

The aim of this study is to evaluate the hypotensive effects and vascular reactivity of Popusa extracts and its pure isolated compounds.

METHODS

Hydroalcoholic extract of Xenophyllum poposum (HAE X. poposum; 40 mg/kg dose) were administered to rats by gavage and mean arterial pressures were recorded. Organ bath studies were conducted in endothelium-intact and denuded rings, and the vascular reactivity of the HAE X. poposum extract and its isolated compounds were compared and analysed. Cytosolic Ca²⁺ was measured in vascular smooth muscle cell line A7r5 using Fura2-AM.

RESULTS

HAE X. poposum significantly reduced the mean arterial blood pressure and heart rate in normotensive rats chronically treated with the extract, as well as mice acutely treated with the extract. A negative chronotropic effect was observed in the isolated rat heart. HAE X. poposum induced endothelial vasodilation mediated by nitric oxide (NO), reduced the contractile response to PE, and decreased PE-induced intracellular Ca²⁺ influx in vascular smooth muscle cells. Pure compounds isolated from HAE X. poposum such as 4‑hydroxy‑3-(3-methyl-2-butenyl) acetophenone, 5-acetyl-6‑hydroxy‑2-isopropenyl-2, and 3-dihydrobenzofurane (dihydroeuparin) also triggered endothelium-dependent vasodilation.

CONCLUSION

HAE X. poposum decreases blood pressure, heart rate and vascular response. The vasodilation properties of HAE X. poposum extract and its isolated compounds may act through the endothelial nitric oxide synthase, as well as calcium channel blocker mechanisms. The results of the present study provide the first qualitative analysis that supports the use of X. poposum in traditional folk medicine for the treatment of altitude sickness and hypertension.

Chemical and genomic diversity of six Lonicera species occurring in Korea

Lonicera spp. (Caprifoliaceae) are important not only as a common medicinal herb in East Asia but also as one of the most problematic invasive species in North America. In the present study, we performed a systemic analysis of genomic and chemical diversity among six Lonicera species occurring in Korea, L. japonica, L. maackii, L. insularis, L. sachalinensis, L. praeflorens, and L. vesicaria, using chloroplast DNA whole genome shotgun (WGS) sequencing and LC-MS analyses. The phylogenetic and phylochemical relationships did not coincide with each other, but partial consistency could be found among them. InDel-based cDNA marker for authentication was developed based on the genome sequences. Flavonoids, iridoids, and organic acids were identified in the LC-MS analyses, and their inter-species distribution and localization were also revealed.

Chemical Profiling and Comparison of Sangju Ganmao Tablet and Its Component Herbs Using Two-Dimensional Liquid Chromatography to Explore Compatibility Mechanism of Herbs

Sangju Ganmao tablet (SGT), a well-known Chinese patent medicine used to treat cold symptoms, is made from eight herbal medicines. In this study, an off-line hydrophilic interaction × reversed-phase two-dimensional liquid chromatography (HILIC × RP 2D-LC) method was developed to comprehensively separate the chemical constituents of SGT. Through optimization of the experimental conditions, a total of 465 peaks were finally detected in SGT, and the structures of 54 selected compounds were fully identified or tentatively characterized by quadrupole time-of-flight mass spectrometry (qTOF-MS) analysis. The established 2D-LC analysis showed high orthogonality (63.62%) and approximate 11-fold improvement in peak capacity (2399 and 1099, obtained by two calculation methods), in contrast to conventional one-dimensional RPLC separation. The eight component herbs of SGT were also respectively separated by using the 2D-LC system, and we found that a total of 12 peaks detected in SGT were not discovered in any component herbs. These newly generated chemical constituents would benefit better understanding of the compatibility mechanism of the component herbs. The strategy established in this study could be used for systematic chemical comparison of SGT and its component herbs, which contributes to exploration of herbal compatibility mechanism.

Recovery of dietary fiber and polyphenol from grape juice pomace and evaluation of their functional properties and polyphenol compositions

The present work aimed at the recovery and characterization of dietary fiber and polyphenolic compounds extracted from red grape pomace, a by-product generated after grape fruit processing. High contents of total DF were found in the dietary fiber extracts (57.24%), whereas insoluble fiber was the major fraction (51.70%). And it showed good functional properties, including swelling capacity (4.01-8.32 mL g^-1), water holding capacity (1.91-4.23 g g^-1) and oil holding capacity (0.59-0.65 g g^-1). After separation from the dietary fiber, phenolic extracts with high concentrations of total phenolic compounds and total flavonoids, showed high antioxidant activities, while the separated dietary fiber showed little antioxidant activities. This indicated that the phenolic composition is essential for the antioxidant activity of "antioxidant dietary fiber (ADF)". The identification of individual polyphenols was performed applying the HPLC-ESI-MS/MS technique and 31 compounds have been identified belonging to 4 groups, including anthocyanins, flavonols, flavan-3-ols and phenolic acids. Based on this study, we believe grape juice pomace could potentially be exploited as an inexpensive source of natural dietary fiber and phenolics and possibly used as a functional food ingredient.

Attenuation of melanogenesis by Nymphaea nouchali (Burm. f) flower extract through the regulation of cAMP/CREB/MAPKs/MITF and proteasomal degradation of tyrosinase

Medicinal plants have been used to treat diseases from time immemorial. We aimed to examine the efficacy of the ethyl acetate fraction of Nymphaea nouchali flower extract (NNFE) against melanogenesis process, and the underlying mechanisms in vitro and in vivo. Paper spray ionisation mass spectroscopy and (+) mode electrospray ionisation revealed the presence of seven flavonoids, two spermidine alkaloids, 3,4,8,9,10-pentahydroxy-dibenzo[b,d]pyran-6-one, and shoyuflavone C in NNFE. NNFE (100 µg/mL) significantly inhibited the monophenolase and diphenolase activities of mushroom tyrosinase at 94.90 ± 0.003% and 93.034 ± 0.003%, respectively. NNFE significantly suppressed cellular tyrosinase activity and melanin synthesis in vitro in melan-a cells and in vivo in HRM2 hairless mice. Furthermore, NNFE inhibited tyrosinase (TYR), tyrosinase-related protein (TYRP)-1, TYRP-2, and microphthalmia-associated transcription factor (MITF) expression, thereby blocking melanin synthesis. In particular, NNFE suppressed cAMP production with subsequent downregulation of CREB phosphorylation. Additionally, it stimulated MAP kinase phosphorylation (p38, JNK, and ERK1/2) and the proteasomal debasement pathway, leading to degradation of tyrosinase and MITF and the suppression of melanin production. Moreover, selective inhibitors of ERK1/2, JNK, and p38 attenuated NNFE inhibitory effects on melanogenesis, and MG-132 (a proteasome inhibitor) prevented the NNFE-induced decline in tyrosinase protein levels. In conclusion, these findings indicate that NNFE is a potential therapy for hyperpigmentation.

Towards better quality criteria of European honeydew honey: Phenolic profile and antioxidant capacity

Concerning the particular nutritive value of honeydew honey compared to blossom honey, and small number of studies defining botanical origin of honeydew honey, comprehensive analysis of phenolic profile of 64 honeydew honey samples of specific botanical origin was performed. Two advanced techniques of liquid chromatography hyphenated with mass spectrometry were used for identification of a total of 52 compounds and quantification of 25 of them. Pattern recognition analysis applied on data on phenolic compounds content confirmed that quercetin, naringenin, caffeoylquinic acid, hydroxyphenylacetic acid, apigenin and genistein, could be considered as potential markers of botanical origin of honeydew honey. Spectroscopic and electrochemical approaches were applied for the evaluation of the antioxidant capacity. Quercus sps. samples, Quercus frainetto and Quercus ilex, showed high biological activity and specific chemical composition. Additionally, cyclic voltammetry profiles were used for characterization and natural clustering of honeydew honey for the first time.

Identification of naringin metabolites mediated by human intestinal microbes with stable isotope-labeling method and UFLC-Q-TOF-MS/MS

Widely presented in medicinal plants, naringin is one of the major flavanones with various pharmaceutical bioactivities. After oral administration, naringin predominantly undergoes metabolisms mediated by liver cytochrome P450 and gut microbes, while its human microbes-mediated metabolic profiling is still largely obscure due to the endogenous interferences, which makes it extremely difficult to analyze metabolites precisely. In this study, we aim of systematically investigating the biotransformation of naringin mediated by human intestinal microbes through applying stable isotope-labeling method. [2',3',5',6'-D₄]naringin was synthesized and incubated anaerobically with human gut microbes. A total of 13 microbial metabolites were detected and identified by UFLC-Q-TOF-MS/MS, among which 5 were reported for the first time. Furthermore, the proposed metabolic pathway revealed that naringin went through extensive phase I metabolism in human intestinal microbes. Of note, diverse metabolic profiles of naringin among human participants were obtained, which could be attributed to the distinct gut microbiota compositions of individuals.

Analysis of Fluorescence Spectra of Citrus Polymethoxylated Flavones and Their Incorporation into Mammalian Cells

Citrus polymethoxylated flavones (PMFs) influence biochemical cascades in human diseases, yet little is known about how these compounds interact with cells and how these associations influence the actions of these compounds. An innate attribute of PMFs is their ultraviolet-light-induced fluorescence, and the fluorescence spectra of 14 PMFs and 7 PMF metabolites were measured in methanol. These spectra were shown to be strongly influenced by the compounds' hydroxy and methoxy substituents. For a subset of these compounds, the fluorescence spectra were measured when bound to human carcinoma Huh7.5 cells. Emission-wavelength maxima of PMF metabolites with free hydroxyl substituents exhibited 70-80 nm red shifts when bound to the Huh7.5 cells. Notable solvent effects of water were observed for nearly all these compounds, and these influences likely reflect the effects of localized microenvironments on the resonance structures of these compounds when bound to human cells.

Identification of Vitamin D3 Oxidation Products Using High-Resolution and Tandem Mass Spectrometry

In a successful fortification program, the stability of micronutrients added to the food is one of the most important factors. The added vitamin D3 is known to sometimes decline during storage of fortified milks, and oxidation through fatty acid lipoxidation could be suspected as the likely cause. Identification of vitamin D3 oxidation products (VDOPs) in natural foods is a challenge due to the low amount of their contents and their possible transformation to other compounds during analysis. The main objective of this study was to find a method to extract VDOPs in simulated whole milk powder and to identify these products using LTQ-ion trap, Q-Exactive Orbitrap and triple quadrupole mass spectrometry. The multistage mass spectrometry (MSⁿ) spectra can help to propose plausible schemes for unknown compounds and their fragmentations. With the growth of combinatorial libraries, mass spectrometry (MS) has become an important analytical technique because of its speed of analysis, sensitivity, and accuracy. This study was focused on identifying the fragmentation rules for some VDOPs by incorporating MS data with in silico calculated MS fragmentation pathways. Diels-Alder derivatization was used to enhance the sensitivity and selectivity for the VDOPs' identification. Finally, the confirmed PTAD-derivatized target compounds were separated and analyzed using ESI(+)-UHPLC-MS/MS in multiple reaction monitoring (MRM) mode. Graphical Abstract ᅟ.

Pharmacokinetics and Biliary Excretion of Fisetin in Rats

The hypothesis of this study is that fisetin and phase II conjugated forms of fisetin may partly undergo biliary excretion. To investigate this hypothesis, male Sprague-Dawley rats were used for the experiment, and their bile ducts were cannulated with polyethylene tubes for bile sampling. The pharmacokinetic results demonstrated that the average area-under-the-curve (AUC) ratios ( k (%) = AUC_conjugate/AUC_free-form) of fisetin, its glucuronides, and its sulfates were 1:6:21 in plasma and 1:4:75 in bile, respectively. Particularly, the sulfated metabolites were the main forms that underwent biliary excretion. The biliary excretion rate ( k_BE (%) = AUC_bile/AUC_plasma) indicates the amount of fisetin eliminated by biliary excretion. The biliary excretion rates of fisetin, its glucuronide conjugates, and its sulfate conjugates were approximately 144, 109, and 823%, respectively, after fisetin administration (30 mg/kg, iv). Furthermore, biliary excretion of fisetin is mediated by P-glycoprotein.

Phytochemical Composition of the Decoctions of Greek Edible Greens (Chórta) and Evaluation of Antioxidant and Cytotoxic Properties

Wild or semi-wild edible greens (chórta) are an integral part of the traditional Greek Mediterranean diet due to their nutritional value, containing various phytonutrients beneficial to human health. Water-based decoctions of chórta are widely consumed in Greek alternative medicine as health promoting agents. This study examined the chemical profile of the decoctions of eight edible plants, Cichorium intybus, C. endivia, C. spinosum, Crepis sancta, Sonchus asper, Carthamus lanatus, Centaurea raphanina, and Amaranthus blitum, by UPLC-ESI-HRMS and HRMS/MS analysis, to determine possibly bioactive constituents. The profiles of the plants from the Asteraceae family are dominated by the presence of phenolic acids and flavonoid derivatives, whereas the A. blitum decoction is rich in triterpene saponins. Interestingly, the Centaurea raphanina decoction was found to be extremely rich in flavanones, particularly in the aglycone pinocembrin. Further phytochemical investigation and fractionation of this extract resulted in the isolation and identification of five compounds: phlorin (1), syringin (2), pinocembrin (3), pinocembroside (4), and pinocembrin-7-O-neohesperidoside (5). The extracts were also tested for their antioxidant and differential cytotoxic activity against tumor cells. C. raphanina was found to be differentially toxic against metastatic tumor cells. In conclusion, we found that Greek edible greens are a rich source of bioactive secondary metabolites and their consumption could contribute to the maintenance of overall health.

Non-targeted glycosidic profiling of international wines using neutral loss-high resolution mass spectrometry

Many metabolites naturally occur as glycosides, since sugar moieties can be crucial for their biological activity and increase their water solubility. In the plant kingdom they may occur as glycosides or sugar esters, depending on precursor chemical structure, and in wine they have traditionally attracted attention due to their organoleptic properties, such as astringency and bitterness, and because they affect the colour and aroma of wines. A new approach directed at detailed description of glycosides in a large selection of monovarietal wines (8 samples each of Pinot Blanc, Muller Thurgau, Riesling, Traminer, Merlot, Pinot Noir and Cabernet Sauvignon) was developed by combining high performance liquid chromatography with high resolution tandem mass spectrometry. Analytical separation was performed on an Accucore™ Polar Premium LC column, while mass analysis was performed in negative ion mode with an non-targeted screening approach, using a Full MS/AIF/NL dd-MS² experiment at a resolving power of 140,000 FWHM. Over 280 glycoside-like compounds were detected, of which 133 (including low-molecular weight phenols, flavonoids and monoterpenols) were tentatively identified in the form of pentose (6), deoxyhexose (17), hexose (73), hexose-pentose (16), hexose-deoxyhexose (7), dihexose (5) and hexose ester (9) derivatives. It was not possible to univocally define the corresponding chemical structure for the remaining 149 glycosides. Non-parametric statistical analysis showed it was possible to well characterise the glycosylated profile of all red and Traminer wines, while the identified glycosides were almost entirely lacking in Pinot Blanc, Riesling and Muller Thurgau wines. Also Tukey's Honestly Significant Difference test (p < 0.05) and Principal Component Analysis confirmed that it was possible to almost entirely distinguish the selected red wines from each other according to their glycosylated profile.

Characterization by liquid chromatography-mass spectrometry and antioxidant activity of an ethanolic extract of Inula viscosa leaves

Inula viscosa (I. viscosa) is a common Mediterranean plant, well known for its content on bioactive molecules. The chemical composition of an ethanolic extract from I. viscosa leaves, growing in Algeria, was analysed by liquid chromatography coupled to photodiode array detection and electrospray ionization mass spectrometry (LC-DAD-ESI-MS/MS) operating in negative and positive mode. The methodology used revealed the presence of 51 compounds from which 47 were putatively identified, including 11 phenolic acids, 23flavonoids, one lignan and 12 terpenoids. Twenty-six of these compounds are described for the first time in I. viscosa. Antioxidant activity was measured using three different and complementary chemical assays: DPPH radical scavenging activity, oxygen radical absorbance capacity (ORAC) and hydroxyl radical scavenging capacity (HOSC). Results demonstrate that ethanolic leaf extract exhibit a high scavenging ability against DPPH (157.72 ± 6.45 μM TE/g DW), peroxyl (4471.42 ± 113.16 μM TE/g DW) and hydroxyl (630.10 ± 17.81 μM TE/g DW) radicals, indicating that I. viscosa can be a promising source of bioactive compounds.

Antioxidative, Antiproliferative and Antimicrobial Activities of Phenolic Compounds from Three Myrcia Species

Myrcia bella Cambess., Myrcia fallax (Rich.) DC. and Myrcia guianensis (Aubl.) DC. (Myrtaceae) are trees found in Brazilian Cerrado. They have been widely used in folk medicine for the treatment of gastrointestinal disorders, hemorrhagic and infectious diseases. Few reports have been found in the literature connecting their phenolic composition and biological activities. In this regard, we have profiled the main phenolic constituents of Myrcia spp. leaves extracts by ESI(−)Q-TOF-MS. The main constituents found were ellagic acid (M. bella), galloyl glucose isomers (M. guianensis) and hexahydroxydiphenic (HHDP) acid derivatives (M. fallax). In addition, quercetin and myricetin derivatives were also found in all Myrcia spp. extracts. The most promising antioxidant activity, measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, was found for M. fallax extracts (EC50 8.61 ± 0.22 µg·mL−1), being slightly less active than quercetin and gallic acid (EC50 2.96 ± 0.17 and 2.03 ± 0.02 µg·mL−1, respectively). For in vitro antiproliferative activity, M. guianensis showed good activity against leukemia (K562 TGI = 7.45 µg·mL−1). The best antimicrobial activity was observed for M. bella and M. fallax to Escherichia coli (300 and 250 µg·mL−1, respectively). In conclusion, the activities found are closely related to the phenolic composition of these plants.

Remela de cachorro (Clavija lancifolia Desf.) fruits from South Amazon: Phenolic composition, biological potential, and aroma analysis

Remela de cachorro (Clavija lancifolia Desf.) is an Amazonian native fruit consumed specially in the Purus microregion. Because of its rarity, restricted consumption, and the lack of knowledge about its chemical composition, remela de cachorro fruit was studied in relation to its phenolic and aroma constitution. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), 11 compounds (flavonoids and its glucosides along with organic acids) were tentatively identified by fragmentation patterns. A previously validated method was applied to quantify common antioxidant compounds in the raw pulps, for which kaempferol was the main compound. Gas chromatography mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME) was employed to assess the aroma composition of remela de cachorro fruit. A total of 27 volatile organic compounds (VOCs) were identified for this fruit, for which benzaldehyde and linalool were the main VOCs. Furthermore, biological activities, such as antioxidant capacity (ABTS, DPPH, and ORAC methods), cytotoxicity, and α-glucosidase and lipase inhibitions of the hydroalcoholic extract of remela de cachorro fruit were evaluated. In vitro biological assays revealed the potential of this fruit as a bioactive food that should be further studied and explored in Amazonian products.

UFLC-Q-TOF-MS/MS-Based Screening and Identification of Flavonoids and Derived Metabolites in Human Urine after Oral Administration of Exocarpium Citri Grandis Extract

Exocarpium Citri grandis (ECG) is an important Traditional Chinese Medicine (TCM) for the treatment of cough and phlegm, and the flavonoids contained were considered the main effective components. To date, the systematic chemical profiling of these flavonoids and derived in vivo metabolites in human have not been well investigated. ECG was extracted using boiling water and then provided to volunteers for oral administration. Following the ingestion, urine samples were collected from volunteers over 48 h. The extract and urine samples were analyzed using ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS) system to screen and identify flavonoids and derived in vivo metabolites. A total of 18 flavonoids were identified in the ECG extract, and 20 metabolites, mainly glucuronide and sulfate conjugates, were screened in urine samples collected post consumption. The overall excretion of naringenin metabolites corresponded to 5.45% of intake and occurred mainly within 4–12 h after the ingestion. Meanwhile, another 29 phenolic catabolites were detected in urine. Obtained data revealed that flavonoids were abundant in the ECG extract, and these components underwent extensive phase II metabolism in humans. These results provided valuable information for further study of the pharmacology and mechanism of action of ECG.

Ultrasound-assisted aqueous extraction, LC-MS/MS analysis and radiomodulating capability of autochthonous Italian sweet cherry fruits

The current cancer treatment scenario lacks drugs acting as both radiosensitizer and radioprotector agents. In this context, the radiomodulatory properties exerted by an aqueous extract from the fruits of the Italian Prunus avium cv. Della Recca (PaDRw) were investigated. The extract, obtained through an environmentally-friendly ultrasound-assisted extraction, seemed to act as a radioprotector at lower tested doses (25 and 50 μg mL^-1) and a radiosensitizer at 400 and 500 μg mL^-1 dose levels towards the neuroblastoma SH-SY5Y cell line, irradiated with four graded X-ray doses (0, 0.5, 2, and 4 Gy). The fractionation of PaDRw by Amberlite XAD-4 non-ionic polymeric resin, coupled to LC-UV-MS/MS techniques, proved to be efficient also in the disclosure of lower constituents. About 63% of the whole PaDRw extract was constituted of hexitol, followed by fructose (∼22.8%) and glucose (∼10.7%). Chlorogenic acids and flavonoids, which accounted only for ∼2.2%, were hypothesized to be the main actors in PaDRw-induced radiomodulation.

Recent (2000-2015) developments in the analysis of minor unknown natural products based on characteristic fragment information using LC-MS

Liquid chromatography-Mass Spectrometry (LC-MS) has been widely used in natural product analysis. Global detection and identification of nontargeted components are desirable in natural product research, for example, in quality control of Chinese herbal medicine. Nontargeted components analysis continues to expand to exciting life science application domains such as metabonomics. With this background, the present review summarizes recent developments in the analysis of minor unknown natural products using LC-MS and mainly focuses on the determination of the molecular formulae, selection of precursor ions, and characteristic fragmentation patterns of the known compounds. This review consists of three parts. Firstly, the methods used to determine unique molecular formula of unknown compounds such as accurate mass measurements, MSⁿ spectra, or relative isotopic abundance information, are introduced. Secondly, the methods improving signal-to-noise ratio of MS/MS spectra by manual-MS/MS or workflow targeting-only signals were elucidated; pure precursor ions can be selected by changing the precursor ion isolated window. Lastly, characteristic fragmentation patterns such as Retro-Diels-Alder (RDA), McLafferty rearrangements, "internal residue loss," and so on, occurring in the molecular ions of natural products are summarized. Classical application of characteristic fragmentation patterns in identifying unknown compounds in extracts and relevant fragmentation mechanisms are presented (RDA reactions occurring readily in the molecular ions of flavanones or isoflavanones, McLafferty-type fragmentation reactions of some natural products such as epipolythiodioxopiperazines; fragmentation by "internal residue loss" possibly involving ion-neutral complex intermediates). © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:202-216, 2018.

Flavonoid Constituents of Phlomis (Lamiaceae) Species Using Liquid Chromatography Mass Spectrometry

INTRODUCTION

Phlomis is one of the medicinal genera of Lamiaceae. This genus has unique medicinal properties. Consequently, appropriate methods need to be described for the identification of the chemical compounds.

OBJECTIVE

A liquid chromatography tandem mass spectrometry (LC-MS/MS) technique on a triple quadrupole mass spectrometer (TQMS) was used for separation and identification of leaf flavonoid compounds for seven Phlomis species including Phlomis kurdia, Ph. aucheri, Ph. olivieri, Ph. bruguieri, Ph. persica, Ph. anisodonta and Ph. elliptica.

METHODOLOGY

The flavonoid solution of air-dried leaves (10.5 g) was extracted using 85% methanol. The chromatogram was treated with three systems: methanol-water, chloroform-methanol and acetic acid. The extracts were analysed using LC-MS/MS. The MS² detection was performed under negative mode electrospray ionisation (ESI). The identification of constituents was based on authentic references used in the identification process.

RESULTS

A total of 35 chemical compounds were detected from which 32 were identified as flavonoids through comparison with published literature and reference standards. These compounds were distributed in four flavonoid classes. Flavones (12), flavonols (11), flavanones (8) and flavane (1) were the main groups appearing in almost all of the studied samples. The flavonoids such as naringenin, chrysoeriol, eriodictyol, dimethoxyflavanone, apigenin, luteolin, kaempferol and rhamnetin were in high proportions. Moreover, 22 flavonoid compounds were first reported in this study for Phlomis species.

CONCLUSION

The fragmentation patterns of the compounds during collision induced dissociation (CID) clarified information of the compounds analysed. The detailed flavonoid compositions of Phlomis species provide the appropriate context from phytochemical and phytotherapeutics points of view. Copyright © 2017 John Wiley & Sons, Ltd.

Chromatographic and Spectroscopic Identification and Recognition of Natural Dyes, Uncommon Dyestuff Components, and Mordants: Case Study of a 16th Century Carpet with Chintamani Motifs

A multi-tool analytical practice was used for the characterisation of a 16th century carpet manufactured in Cairo. A mild extraction method with hydrofluoric acid has been evaluated in order to isolate intact flavonoids and their glycosides, anthraquinones, tannins, and indigoids from fibre samples. High-performance liquid chromatography coupled to spectroscopic and mass spectrometric detectors was used for the identification of possible marker compounds with special attention paid to natural dyes present in the historical samples. Weld, young fustic, and soluble redwood dye were identified as the dye sources in yellow thread samples. Based on the developed method, it was possible to establish that red fibres were coloured with lac dye, whereas green fibre shades were obtained with indigo and weld. Tannin-containing plant material in combination with indigo and weld were used to obtain the brown hue of the thread. Hyphenation of high-performance liquid chromatography (HPLC) with quadrupole time-of-flight mass spectrometry (QTOF MS) and triple-quadrupole mass spectrometry (QqQ MS) enabled us to recognise four uncommon and thus-far unknown dye components that were also found in the historical samples. These compounds probably represent a unique fingerprint of dyed threads manufactured in a Turkish workshop. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) were used for the identification and characterisation of substrates and mordants present in the historical carpet. Carbon and oxygen were detected in large quantities as a part of the wool protein. The presence of aluminium, iron, and calcium indicated their usage as mordants. Trace amounts of copper, silica, and magnesium might originate from the contaminants. FT-IR analysis showed bands characteristic for woollen fibres and SEM micrographs defined the structure of the wool.

Optimization and validation of reverse phase HPLC method for qualitative and quantitative assessment of polyphenols in seaweed

A simple reverse phase-high performance liquid chromatography (RP-HPLC) coupled to a diode array detector (DAD) and negative ion electrospray mass spectrometer (ESI-MS) method was developed for simultaneous identification and quantification of phenolic antioxidants in seaweed. The proposed method was validated in terms of linearity, limits of detection (LOD), limits of quantification (LOQ), recovery and intermediate precision. The calibration curves were linear with correlation coefficient ranging from 0.9909 to 0.9997 while the values of LOD (0.26-0.82mg/L), LOQ (0.77-2.50mg/L), recovery (≥97.2%) and precision in terms of retention time (%RSD ≤2.27) and peak area (% RSD ≤5.11) were satisfactory. Brown seaweed Himanthalia elongata used in this study was extracted with 60% methanol and the crude extract was cleaned with SPE (Solid Phase Extraction) cartridge. HPLC-DAD-MS/MS analysis of the SPE fraction allowed the identification of 7 phenolic compounds comprising phlorotannins, hydroxybenzoic acid, hydroxycinnamic acid and flavonols subclasses of polyphenols. Quantitative analysis of these compounds revealed the presence of phloroglucinol (394.1±4.33μg/g), gallic acid (96.3±3.12μg/g), chlorogenic acid (38.8±1.94μg/g), caffeic acid (44.4±2.72μg/g), ferulic acid (17.6±0.85μg/g), myricetin (8.6±0.85μg/g) and quercetin (4.2±0.15μg/g), in the extract. The SPE fraction were tested for antioxidant capacity which were significantly (P <0.05) higher (EC50; 14.5±0.57mg/g) than the ascorbic acid (EC50; 35.8±0.59mg/g) and the crude extract (EC50; 46.3±0.48mg/g). The occurrence of all these phenolic antioxidant compounds in H. elongata extract suggested that the developed method is sensitive enough and reproducible and could be used for qualitative and quantitative assessment of polyphenols in seaweed.

Extraction, characterization and biological activity of citrus flavonoids

Citrus is one of the largest and most popular fruit crops commercially grown across the globe. It is not only important in terms of economy but is also popular for its nutritional benefits to human and farm animals. Citrus is available in several varieties, all with attractive colors. It is consumed either fresh or in processed form. After processing, approximately 50% of the fruit remains unconsumed and discarded as waste. The latter includes fruit pith residue, peels and seeds. Direct disposal of these wastes to the environment causes serious problems as these contain bioactive compounds. Release of these bioactive compounds to the open landfills cause bad odor and spread of diseases, and disposal to water bodies or seepage to the underground water table deteriorates water quality and harms aquatic life. In this regard, a number of research are being focused on the development of better reuse methods to obtain value-added phytochemicals as well as for safe disposal. The important phytochemicals obtained from citrus include essential oils, flavonoids, citric acid, pectin, etc., which have now become popular topics in industrial research, food and synthetic chemistry. The present article reviews recent advances in exploring the effects of flavonoids obtained from citrus wastes, the extraction procedure and their usage in view of various health benefits.

High throughput mass spectrometry-based characterisation of Arabidopsis thaliana group H glycosyltransferases

In this report, we cloned and characterised four members of group H glycosyltransferases (GTs) by studying their substrate specificities and kinetics. The formation of products and possible glycosylation position was confirmed using MS/MS. The results revealed that 76E1 and 76E5 have broader donor specificity, including UDP-glucose (UDPGlc), UDP-galactose (UDPGal) and UDP-N-acetylglucosamine (UDPGlcNAc) with various flavonoids as acceptor substrates. Pseudo-single substrate kinetics data showed a relatively low K_M, indicating a high affinity for substrate UDPGlc and also supported that 76E5 is more of a galactosyl and N-acetylglucosamine transferase. Sequence alignment and site-directed mutagenesis studies indeed suggested that serine is a crucial residue in the UDPGlcNAc and UDPGal activity.

We cloned and characterised four group H glycosyltransferases by studying their substrate specificities and kinetics. Sequence alignment and site-directed mutagenesis studies showed that serine is a crucial residue for UDPGlcNAc and UDPGal activity.

Flavonoids and Ellagitannins Characterization, Antioxidant and Cytotoxic Activities of Phyllanthus acuminatus Vahl

The phenolic composition of leaves from Phyllanthus acuminatus L., a plant commonly used in Costa Rica as traditional medicine, was studied using UPLC-ESI-MS on an enriched phenolic extract. A total of 20 phenolic compounds were identified, comprising eight flavonoids (two flavanones-pinocembrin isomers and six derivatives from apigenin, chrysin, quercetin, and kaempferol); seven ellagitannins, two flavan-3-ols (prodelphinidin B dimer and (epi)gallocatechin); and three phenolic acids (ellagic acid, trimethylellagic acid, and ferulic acid). All of these compounds are reported for the first time in P. acuminatus, while previously reported in the genus Phyllanthus. Antioxidant evaluation was performed for P. acuminatus phenolic extract obtaining DPPH results with a remarkably low IC50 value of 0.15 μg/mL. Also, cytotoxicity on gastric AGS and colon SW20 adenocarcinoma cell lines was evaluated, and highly promising results were obtained, with IC50 values of 11.3 μg/mL and 10.5 μg/mL, respectively. Furthermore, selectivity index values obtained when comparing cytotoxicity on normal Vero cells was SI > 20 for both cancer cell lines, indicating a particularly high selectivity. Additionally, Justicidin B, a metabolite extensively studied for its antitumoral activity, was isolated from a non-polar extract of P. acuminatus, and comparatively evaluated for both bioactivities. The DPPH value obtained for Justicidin B was moderate (IC50 = 14.28 μg/mL), while cytotoxicity values for both AGS (IC50 = 19.5 μg/mL) and SW620 (IC50 = 24.8 μg/mL) cell lines, as well as selectivity when compared with normal Vero cells (SI = 5.4 and 4.2 respectively), was good, but lower than P. acuminatus extract. These preliminary results suggest that P. acuminatus enriched phenolic extract containing flavonoids, ellagitannins, flavan-3-ols, and phenolic acids, reported for the first time in this plant, could be of interest for further cancer cytotoxicity studies to elucidate structure-bioactivity relationships, and the molecular mechanisms and pathways.