Mass spectrometric identification and quantification of glycosyl flavonoids, including dihydrochalcones with neutral loss scan mode

Volatile Semiochemicals Emitted by Beauveria bassiana Modulate Larval Feeding Behavior and Food Choice Preference in Spodoptera frugiperda (Lepidoptera: Noctuidae)

Beauveria bassiana is an entomopathogenic fungus that parasitizes and kills insects. The role of volatile organic compounds (VOCs) emitted by B. bassiana acting as semiochemicals during its interaction with lepidopterans is poorly explored. Here, we studied the effect of VOCs from B. bassiana and 3-methylbutanol (as a single compound) on the feeding behavior of L2 larvae of Spodoptera frugiperda in sorghum plants. Additionally, we assessed whether fungal VOCs induce chemical modifications in the plants that affect larval food preferences. Metabolomic profiling of plant tissues was performed by mass spectrometry and bioassays in a dual-choice olfactometer. The results showed that the larval feeding behavior was affected by the B. bassiana strain AI2, showing that the insect response is strain-specific. Furthermore, 80 µg of 3-methylbutanol affected the number of bites. The larval feeding choice was dependent on the background context. Fragment spectra and a matching precursor ion mass of 165.882 m/z enabled the putative identification of 4-coumaric acid in sorghum leaves exposed to fungal VOCs, which may be associated with larval deterrent responses. These results provide valuable insights into the bipartite interaction of B. bassiana with lepidopterans through VOC emission, with the plant as a mediator of the interaction.

A Comprehensive Study on Lathyrus tuberosus L.: Insights into Phytochemical Composition, Antimicrobial Activity, Antioxidant Capacity, Cytotoxic, and Cell Migration Effects

In this study, in vitro antioxidant, antimicrobial, cytotoxic, and cell migration effects of phenolic compounds of Lathyrus tuberosus leaves, known in the Transylvanian ethnomedicine, were investigated. Ultra-high-performance liquid chromatography-tandem mass spectrometry was employed for the analysis of the ethanolic and aqueous extracts. The antimicrobial properties were determined using a conventional microdilution technique. Total antioxidant capacity techniques were used using cell-free methods and cell-based investigations. Cytotoxic effects were conducted on 3T3 mouse fibroblasts and HaCaT human keratinocytes using a multiparametric method, assessing intracellular ATP, total nucleic acid, and protein levels. Cell migration was visualized by phase-contrast microscopy, employing conventional culture inserts to make cell-free areas. Together, 93 polyphenolic and monoterpenoid compounds were characterized, including flavonoid glycosides, lignans, hydroxycinnamic acid, and hydroxybenzoic acid derivatives, as well as iridoids and secoiridoids. The ethanolic extract showed high antioxidant capacity and strong antimicrobial activity against Bacillus subtilis (MIC80 value: 354.37 ± 4.58 µg/mL) and Streptococcus pyogenes (MIC80 value: 488.89 ± 4.75 µg/mL). The abundance of phenolic compounds and the results of biological tests indicate the potential for L. tuberosus to serve as reservoirs of bioactive compounds and to be used in the development of novel nutraceuticals.

Alternative Identification of Glycosides Using MS/MS Matching with an In Silico-Modified Aglycone Mass Spectra Library

Glycosylation of metabolites serves multiple purposes. Adding sugars makes metabolites more water soluble and improves their biodistribution, stability, and detoxification. In plants, the increase in melting points enables storing otherwise volatile compounds that are released by hydrolysis when needed. Classically, glycosylated metabolites were identified by mass spectrometry (MS/MS) using [M-sugar] neutral losses. Herein, we studied 71 pairs of glycosides with their respective aglycones, including hexose, pentose, and glucuronide moieties. Using liquid chromatography (LC) coupled to electrospray ionization high-resolution mass spectrometry, we detected the classic [M-sugar] product ions for only 68% of glycosides. Instead, we found that most aglycone MS/MS product ions were conserved in the MS/MS spectra of their corresponding glycosides, even when no [M-sugar] neutral losses were observed. We added pentose and hexose units to the precursor masses of an MS/MS library of 3057 aglycones to enable rapid identification of glycosylated natural products with standard MS/MS search algorithms. When searching unknown compounds in untargeted LC-MS/MS metabolomics data of chocolate and tea, we structurally annotated 108 novel glycosides in standard MS-DIAL data processing. We uploaded this new in silico-glycosylated product MS/MS library to GitHub to enable users to detect natural product glycosides without authentic chemical standards.

Network Pharmacology- and Molecular Dynamics Simulation-Based Bioprospection of Aspalathus linearis for Type-2 Diabetes Care

The medicinal herb Aspalathus linearis (rooibos) is globally recognized in type-2 diabetes mellitus (T2DM) treatment due to its known and distinctive compounds. This work utilized network pharmacology (NP) coupled with molecular dynamics simulation in gaining new insight into the anti-diabetic molecular mechanism of action of rooibos teas. It looked at the interactions between rooibos constituents with various relevant protein receptors and signaling routes associated with T2DM progression. The initial analysis revealed 197 intersecting gene targets and 13 bioactive rooibos constituents linked to T2DM. The interactions between proteins and compounds to the target matrix were generated with the Cystoscope platform and STRING database. These analyses revealed intersecting nodes active in T2DM and hypoxia-inducible factor 1 (HIF-1) as an integral receptors target. In addition, KEGG analysis identified 11 other pathways besides the hub HIF-1 signaling route which may also be targeted in T2DM progression. In final molecular docking and dynamics simulation analysis, a significant binding affinity was confirmed for key compound-protein matrices. As such, the identified rooibos moieties could serve as putative drug candidates for T2DM control and therapy. This study shows rooibos constituents' interaction with T2DM-linked signaling pathways and target receptors and proposes vitexin, esculin and isovitexin as well as apigenin and kaempferol as respective pharmacologically active rooibos compounds for the modulation of EGFR and IGF1R in the HIF-1 signaling pathway to maintain normal homeostasis and function of the pancreas and pancreatic β-cells in diabetics.

Characterization of Extracts of Coffee Leaves (Coffea arabica L.) by Spectroscopic and Chromatographic/Spectrometric Techniques

Coffea arabica L. leaves represent a viable alternative to the canonical matrices used for preparation of beverages, such as tea leaves and grounded coffee beans. Coffee leaves infusions are rich in antioxidant phenolic compounds and have a lower concentration of caffeine. Due to increasing interest in this field, a complete study of the bioactive compounds as chlorogenic acids, xanthones and alkaloids is noteworthy. C. arabica leaves were subjected to ultrasound-assisted extraction, and the extracts were studied via nuclear magnetic resonance spectroscopy (NMR) and chromatographic techniques coupled with mass spectrometry (HPLC-MSn) to identify and quantify the secondary metabolites profile through an untargeted data dependent approach. A quantitative analysis was performed for the major components—chlorogenic acids, mangiferin, caffeine and trigonelline—via HPLC-MS in Single Ion Monitoring (SIM) mode. In total, 39 compounds were identified. The presence of these bioactive compounds proved the strong potential of C. arabica leaves as functional food and as an alternative to classic infused beverages.

Mentha pulegium L. (Pennyroyal, Lamiaceae) Extracts Impose Abortion or Fetal-Mediated Toxicity in Pregnant Rats; Evidenced by the Modulation of Pregnancy Hormones, MiR-520, MiR-146a, TIMP-1 and MMP-9 Protein Expressions, Inflammatory State, Certain Related Signaling Pathways, and Metabolite Profiling via UPLC-ESI-TOF-MS

Pregnant women usually turn to natural products to relieve pregnancy-related ailments which might pose health risks. Mentha pulegium L. (MP, Lamiaceae) is a common insect repellent, and the present work validates its abortifacient capacity, targeting morphological anomalies, biological, and behavioral consequences, compared to misoprostol. The study also includes untargeted metabolite profiling of MP extract and fractions thereof viz. methylene chloride (MecH), ethyl acetate (EtOAc), butanol (But), and the remaining liquor (Rem. Aq.) by UPLC-ESI-MS-TOF, to unravel the constituents provoking abortion. Administration of MP extract/fractions, for three days starting from day 15th of gestation, affected fetal development by disrupting the uterine and placental tissues, or even caused pregnancy termination. These effects also entailed biochemical changes where they decreased progesterone and increased estradiol serum levels, modulated placental gene expressions of both MiR-(146a and 520), decreased uterine MMP-9, and up-regulated TIMP-1 protein expression, and empathized inflammatory responses (TNF-α, IL-1β). In addition, these alterations affected the brain's GFAP, BDNF, and 5-HT content and some of the behavioral parameters escorted by the open field test. All these incidences were also perceived in the misoprostol-treated group. A total of 128 metabolites were identified in the alcoholic extract of MP, including hydroxycinnamates, flavonoid conjugates, quinones, iridoids, and terpenes. MP extract was successful in terminating the pregnancy with minimal behavioral abnormalities and low toxicity margins.

Seasonal Chemical Evaluation of Miconia chamissois Naudin from Brazilian Savanna

Miconia chamissois Naudin is a species from the Cerrado, which is being increasingly researched for its therapeutic potential. The aim of this study was to obtain a standardized extract and to evaluate seasonal chemical variations. Seven batches of aqueous extracts from leaves were produced for the standardization. These extracts were evaluated for total solids, polyphenol (TPC) and flavonoid content (TFC), vitexin derivative content, antioxidant activity; thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC) profiles were generated. For the seasonal study, leaves were collected from five different periods (May 2017 to August 2018). The results were correlated with meteorological data (global radiation, temperature, and rainfall index). Using chromatographic and spectroscopic techniques, apigenin C-glycosides (vitexin/isovitexin) and derivatives, luteolin C-glycosides (orientin/isoorientin) and derivatives, a quercetin glycoside, miconioside B, matteucinol-7-O-β-apiofuranosyl (1 → 6) -β-glucopyranoside, and farrerol were identified. Quality parameters, including chemical marker quantification by HPLC, and biological activity, are described. In the extract standardization process, all the evaluated parameters showed low variability. The seasonality study revealed no significant correlations (p < 0.05) between TPC or TFC content and meteorological data. These results showed that it is possible to obtain extracts from M. chamissois at any time of the year without significant differences in composition.

Neutral loss scan in complement with high-resolution MS/MS: Combination of detection methods for flavonoid and limonoid glycosides analysis

In this study, neutral loss scan and high-resolution MS/MS were used in combination to detect and tentatively identify various flavonoid and limonoid glycosides in navel orange albedo, juice, peel and pulp. These compound classes are of research interest due to their flavour and bioactive properties, and although flavonoid glycosides have been previously studied in other food matrices, to the best of our knowledge, neutral loss scans have not been used for the elucidation of limonoid glycosides. Neutral loss masses of 120, 162 and 308 Da were selected for the detection of hexose, rutinose and neohesperidose-substituted flavonoids, whereas 197 Da was explored for limonoid glycosides due to their tendency to form ammonium adducts. Fragmentation patterns obtained from targeted MS/MS were then used to differentiate rutinose and neohesperidose substituents as well as flavonoid subclasses of flavones, flavanones and flavonols. Additionally, high-resolution MS/MS was also used for the identification of aglycones by accurate mass (to four decimal places), allowing for the differentiation of aglycones with similar unit masses but different chemical formulas. In total, 19 flavonoid glycosides and six limonoid glycosides were detected. This workflow allows for a rapid screening of flavonoid and limonoid glycosides in citrus, which can be further extended to other food products such as tea.

Untargeted Metabolomics Combined with Solid Phase Fractionation for Systematic Characterization of Bioactive Compounds in Hemp with Methane Mitigation Potential

This study systematically evaluates the presence of methane mitigating metabolites in two hemp (Cannabis sativa L.) varieties, Futura 75 and Finola. Hemp metabolites were extracted with methanol and fractionated using Solid Phase Extraction (SPE). Extracts, fractions, and the remaining pulp were screened for their methane mitigating potential using an in vitro model of rumen fermentation. The bioactive metabolites were identified with Liquid Chromatography-Mass Spectrometry (LC-MS). When incubated with a standard feed (maize silage), the extract of Futura 75 significantly reduced methane production compared to that of control (without added extract) and without negative effects on feed degradability and volatile fatty acid patterns. The compounds responsible for the methane mitigating effect were assigned to flavonoid glycosides. However, none of the fractions of Futura 75 or the pulp exhibited similar effect on methane emission. Butyric acid concentration in the fermentation inoculum was significantly increased, which could indicate why methane production was higher, when incubated with the fractions and the pulp. The extract of Finola did not show a similar significant effect, however, there was a numerical tendency towards lower methane production. The difference in methane mitigating properties between Cannabis sativa L. Futura 75 and Finola, could be related to the content of bioactive flavonoids.

Phoenix dactylifera L. date tree pollen fertility effects on female rats in relation to its UPLC-MS profile via a biochemometric approach

Date palm (Phoenix dactylifera L.) is among the most ancient cultivated crops, of special value owing to its fruits high nutritive and economic benefits. Asides, date palm pollen is a high energy material that has been used traditionally used for fertility enhancement. In this study, effects of date palm pollen crude extract and its fractions viz., petroleum ether, methylene chloride, ethyl acetate and n-butanol on the female reproductive system were evaluated for the first time in relation to its metabolite fingerprint. Fertility activity was evaluated in immature female rats by assessing their FSH-, LH- and estrogen- activities. To pinpoint active hormonal agents in crude pollen extract and fractions, UPLC- MS analysis was employed for metabolites profiling, and in correlation to extract/fraction bioassays using multivariate OPLS analysis. Results revealed that both polar n-butanol and non-polar petroleum ether fractions exhibited the strongest activities; with a significant increase in FSH (25.7 mIU/ml in n-butanol group), estradiol (414.7 pg/ml in petroleum ether group) and progesterone levels (122.4 pg/ml in n-butanol group). Correlation between UPLC-MS and fraction bioassays was attempted using multivariate OPLS analysis to reveal for bioactive hits in these fractions. This study provides the first report on the fertility effect of date palm pollen in female rats and in relation to its metabolite fingerprint.

Identification and characterization of glycosyltransferases catalyzing direct xanthone 4-C-glycosylation in Hypericum perforatum

Xanthones are compounds with a diphenyl ether skeleton mainly found in plants and often glycosylated at carbon atoms. Although many C-glycosyltransferases (CGTs) participating in flavone C-glycosylation have been identified, MiCGT from Mangifera indica, adding sugar to an open-chain benzophenone skeleton, is the only identified xanthone biosynthesis-related CGT. Here, we identified two CGTs from Hypericum perforatum that add sugar to the closed-ring xanthone, but not benzophenone. These CGTs catalyze sugar transfer to the C-4 position of norathyriol (1,3,6,7-tetrahydroxyxanthone) to form isomangiferin (1,3,6,7-tetrahydroxyxanthone 4-C-glucoside), a major xanthone C-glucoside. This is the first study to report CGTs that mediate the direct C-glycosylation of xanthone.

Exploring and applying the substrate promiscuity of a C-glycosyltransferase in the chemo-enzymatic synthesis of bioactive C-glycosides

Bioactive natural C-glycosides are rare and chemical C-glycosylation faces challenges while enzymatic C-glycosylation catalyzed by C-glycosyltransferases provides an alternative way. However, only a small number of C-glycosyltransferases have been found, and most of the discovered C-glycosyltransferases prefer to glycosylate phenols with an acyl side chain. Here, a promiscuous C-glycosyltransferase, AbCGT, which is capable of C-glycosylating scaffolds lacking acyl groups, is identified from Aloe barbadensis. Based on the substrate promiscuity of AbCGT, 16 C-glycosides with inhibitory activity against sodium-dependent glucose transporters 2 are chemo-enzymatically synthesized. The C-glycoside 46a shows hypoglycemic activity in diabetic mice and is biosynthesized with a cumulative yield on the 3.95 g L^‒1 scale. In addition, the key residues involved in the catalytic selectivity of AbCGT are explored. These findings suggest that AbCGT is a powerful tool in the synthesis of lead compounds for drug discovery and an example for engineering the catalytic selectivity of C-glycosyltransferases.

C-glycosides are of pharmaceutical interest due to their stability against in vivo hydrolysis, however their enzymatic synthesis faces challenges. Here, the authors report a C-glycosyltransferase from Aloe barbadensis catalysing the C-glycosylation of drug-like acceptors to generate bioactive C-glycosides.

Study of the pharmacokinetics of eriodictyol-6-C-β-d-glucoside, a flavonoid of rooibos (Aspalathus linearis) extract, after its oral administration in mice

Systemic dry syndrome affects quality of life, and various effective methods are being developed for its treatment. We recently found that rooibos (Aspalathus linearis) extract activates muscarinic M₃ receptor and improves dryness in mice and humans. We identified eriodictyol-6-C-β-_D-glucoside (E6CG) as the active component affecting the secretory functions of exocrine glands; however, the pharmacokinetics and distribution of E6CG in exocrine glands have not been elucidated in mice receiving rooibos extract. We have developed a quantification method using LC-MS/MS to detect E6CG without an internal standard. Experiments on C57BL/6 mice administered rooibos extract showed that E6CG was transferred into blood plasma, with its concentration levels peaking 19.3 min after treatment. Substantial levels of E6CG were detected in the submandibular, sublingual, parotid, and lacrimal glands and in the sweat glands in palm skin. This study reports that rooibos extracts containing E6CG can be used as functional foods for improving systemic dryness.

Metabolites profiling of date palm (Phoenix dactylifera L.) commercial by-products (pits and pollen) in relation to its antioxidant effect: a multiplex approach of MS and NMR metabolomics

INTRODUCTION

Phoenix dactylifera L. (date palm) is one of the most valued crops worldwide for its economical and nutraceutical applications of its date fruit (pericarp). Currently date pits, considered as a waste product, is employed as coffee substitute post roasting. Whereas, pollen represents another valuable by-product used as a dietary supplement.

OBJECTIVES

In this study, a large-scale comparative metabolomics approach was performed for the first characterization and standardization of date palm by-products viz., date pits and pollen. Moreover, roasting impact on date pit metabolite composition was also assessed.

METHODS

Metabolites profiling of pits and pollen was determined via a multiplex approach of UPLC-MS and NMR, coupled to multivariate analysis, in relation to its antioxidant activities.

RESULTS

Chemical analyses led to the identification of 67 metabolites viz., phenolic acids, flavonols, fatty acids, sphingolipids, steroids and saponins of which 10 are first time to be reported. The enrichment of steroids in date pollen accounts for its fertility promoting properties, whereas date pit was found a rich source for antioxidant polyphenols using metabolomics.

The Structure and Function of Major Plant Metabolite Modifications

Plants produce a myriad of structurally and functionally diverse metabolites that play many different roles in plant growth and development and in plant response to continually changing environmental conditions as well as abiotic and biotic stresses. This metabolic diversity is, to a large extent, due to chemical modification of the basic skeletons of metabolites. Here, we review the major known plant metabolite modifications and summarize the progress that has been achieved and the challenges we are facing in the field. We focus on discussing both technical and functional aspects in studying the influences that various modifications have on biosynthesis, degradation, transport, and storage of metabolites, as well as their bioactivity and toxicity. Finally, we discuss some emerging insights into the evolution of metabolic pathways and metabolite functionality.

The Potential of South African Herbal Tisanes, Rooibos and Honeybush in the Management of Type 2 Diabetes Mellitus

Diabetes mellitus is a metabolic disease that can lead to high morbidity, mortality and long-term complications. Available treatment strategies, which are mainly based on treating hyperglycemia, with insulin and other pharmacological agents are not completely efficient and can even lead to development of unwanted side effects. Scientific evidence suggests that bioactive compounds from teas and other plant-based foods, which are known source of natural antioxidants, could be an attractive strategy to preferentially treat and manage type 2 diabetes mellitus (T2DM) and thus, have significant therapeutic implications. In this review, we attempt an in-depth analysis and discussion of the current progress in our understanding of the antidiabetic potential of two commercialized South Africa herbal tisanes—Rooibos and Honeybush and their polyphenols.

Adduct ion-targeted qualitative and quantitative analysis of polyoxypregnanes by ultra-high pressure liquid chromatography coupled with triple quadrupole mass spectrometry

Polyoxypregnane and its glycosides (POPs) are frequently present in plants of Asclepiadaceae family, and have a variety of biological activities. There is a great need to comprehensively profile these phytochemicals and to quantify them for monitoring their contents in the herbs and the biological samples. However, POPs undergo extensive adduct ion formation in ESI-MS, which has posed a challenge for qualitative and quantitative analysis of POPs. In the present study, we took the advantage of such extensive adduct ion formation to investigate the suitability of adduct ion-targeted analysis of POPs. For the qualitative analysis, we firstly demonstrated that the sodium and ammonium adduct ion-targeted product ion scans (PIS) provided adequate MS/MS fragmentations for structural characterization of POPs. Aided with precursor ion (PI) scans, which showed high selectivity and sensitivity and improved peak assignment confidence in conjunction with full scan (FS), the informative adduct ion-targeted PIS enabled rapid POPs profiling. For the quantification, we used formic acid rather than ammonium acetate as an additive in the mobile phase to avoid simultaneous formation of sodium and ammonium adduct ions, and greatly improved reproducibility of MS response of POPs. By monitoring the solely formed sodium adduct ions [M+Na]⁺, a method for simultaneous quantification of 25 POPs in the dynamic multiple reaction monitoring mode was then developed and validated. Finally, the aforementioned methods were applied to qualitative and quantitative analysis of POPs in the extract of a traditional Chinses medicinal herb, Marsdenia tenacissima (Roxb.) Wight et Arn., and in the plasma obtained from the rats treated with this herb. The results demonstrated that adduct ion formation could be optimized for the qualitative and quantitative analysis of POPs, and our developed PI/FS-PIS scanning and sole [M+Na]⁺ ion monitoring significantly improved the analysis of POPs in both herbal and biological samples. This study also provides implications for the analysis of other compounds which undergo extensive adduct ion formation in ESI-MS.

Intestinal Transport Characteristics and Metabolism of C-Glucosyl Dihydrochalcone, Aspalathin

Insight into the mechanisms of intestinal transport and metabolism of aspalathin will provide important information for dose optimisation, in particular for studies using mouse models. Aspalathin transportation across the intestinal barrier (Caco-2 monolayer) tested at 1–150 µM had an apparent rate of permeability (P_app) typical of poorly absorbed compounds (1.73 × 10⁻⁶ cm/s). Major glucose transporters, sodium glucose linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), and efflux protein (P-glycoprotein, PgP) (1.84 × 10⁻⁶ cm/s; efflux ratio: 1.1) were excluded as primary transporters, since the P_app of aspalathin was not affected by the presence of specific inhibitors. The P_app of aspalathin was also not affected by constituents of aspalathin-enriched rooibos extracts, but was affected by high glucose concentration (20.5 mM), which decreased the P_app value to 2.9 × 10⁻⁷ cm/s. Aspalathin metabolites (sulphated, glucuronidated and methylated) were found in mouse urine, but not in blood, following an oral dose of 50 mg/kg body weight of the pure compound. Sulphates were the predominant metabolites. These findings suggest that aspalathin is absorbed and metabolised in mice to mostly sulphate conjugates detected in urine. Mechanistically, we showed that aspalathin is not actively transported by the glucose transporters, but presumably passes the monolayer paracellularly.

Characterization of phenolic and other polar compounds in peel and flesh of pink guava (Psidium guajava L. cv. 'Criolla') by ultra-high performance liquid chromatography with diode array and mass spectrometric detection

Pink guava (Psidium guajava L.) is a highly consumed fruit in tropical countries. Despite of interesting research on health effects of this fruit, investigations into the profile of secondary plant metabolites are scarce. In this study, the phenolic compounds in the peel and flesh of pink guava were characterized by ultra-high performance liquid chromatography with diode array and mass spectrometric detection. Sixty phenolic compounds were characterized by MS² and classified as ellagitannins, flavones, flavonols, flavanols, proanthocyanidins, dihydrochalcones, and anthocyanidins, and non-flavonoids such as phenolic acid derivatives, stilbenes, acetophenones, and benzophenones. Forty-two polyphenols are reported for the first time in both peel and flesh, and twenty-four compounds were detected for the first time in P. guajava, e.g., phlorizin, nothofagin, astringin, chrysin-C-glucoside, valoneic acid bilactone, cinnamoyl-glucoside, and two dimethoxycinnamoyl-hexosides.

Ameliorative Effect of Vicenin-2 and Scolymoside on TGFBIp-Induced Septic Responses

Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-β. TGFBIp is released by the human umbilical vein endothelial cells (HUVECs) and functions as a mediator of experimental sepsis. Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in biological processes. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, two active compounds in C. subternata against TGFBIp-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of vicenin-2 or scolymoside were determined by measuring permeability, human neutrophils adhesion and migration, and activation of pro-inflammatory proteins in TGFBIp-activated HUVECs and mice. According to the results, vicenin-2 or scolymoside effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, vicenin-2 or scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6 and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by TGFBIp. Vicenin-2 or scolymoside reduced cecal ligation and puncture (CLP)-induced septic mortality and pulmonary injury. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.

Antitcoagulant and antiplatelet activities of scolymoside

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. Here, the anticoagulant effects of scolymoside, an active compound in C. subternata, were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). The effects of scolymoside on plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) expression were evaluated in tumor necrosis factor (TNF)-α-activated human endothelial cells. Treatment with scolymoside resulted in prolonged aPTT and PT and the inhibition of thrombin and FXa activities and production. In addition, scolymoside inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. Scolymoside also elicited anticoagulant effects in mice, including a significant reduction in the PAI-1 to t-PA ratio. Collectively, these findings indicate that scolymoside possesses anticoagulant activities and could be developed as a novel anticoagulant.

Characterization of the Principal Constituents of Danning Tablets, a Chinese Formula Consisting of Seven Herbs, by an UPLC-DAD-MS/MS Approach

Danning Tablets are a traditional Chinese formula showing broad clinical applications in hepatobiliary diseases and containing a diversity of bioactive chemicals. However, the chemical profiling of the formula, which serves as the material foundation of its efficacy, is really a big challenge as Danning Tablets consist of seven herbs from different origins. An ultra-performance liquid chromatography coupled to diode array detection and electrospray ionization mass spectrometry (UPLC-DAD-ESI-MS/MS) approach was developed to characterize the principal polyphenol constituents in the formula. As a result, a total of 32 constituents, including 14 anthraquinones and their glucosides, four anthrones, two naphthalene glycosides, two stilbenes and 10 flavonoids were identified based on their retention time, UV absorption and MS/MS fragmentation patterns. The sources of these compounds were also illustrated. Most of the bioactive anthraquinone derivatives were found in Rhei Radix et Rhizoma or Polygoni Cuspidati Rhizoma et Radix, which are the Emperor drugs in the formula for its clinic usage. These findings indicate the merit of using this integrated UPLC-DAD-ESI-MS/MS approach to rapidly illustrate the chemical foundation of complex formulas. The present study will facilitate the quality control of Danning Tablet formulas as well as the individual herbs.

Stepped collisional energy MS(All) : an analytical approach for optimal MS/MS acquisition of complex mixture with diverse physicochemical properties

The analysis of complex mixtures is becoming increasingly important in various fields, such as nutrition, medicinal plants and metabolomics. The components contained in such complex mixtures are always characterized with diverse physiochemical properties that pose a major challenge during the optimization of various parameters using liquid chromatography-mass spectrometer (LC-MS). The parameter 'CE energy' that is normally set at a fixed value with a moderate range of CE spread during data-dependent acquisition (DDA) analysis, a prevalent approach for untargeted identification, often fails to generate sufficient MS/MS fragment ions for untargeted identification of components from complex mixtures. Here we developed a simple and generally applicable acquisition method named stepped MS(All) (sMS(All) ) in this study, aiming to obtain optimal MS/MS spectra for identification of chemically diverse compounds from complex mixtures. sMS(All) collects serial MS(All) scans acquired at low CE to gradually ramped-up high CE values in a cycle that conventional DDA scans cannot afford. The resultant MS/MS spectra of each compound were compared and evaluated among serial MS(All) scans, and the optimal spectra were used for identification. An untargeted data analysis strategy was then employed to analyze these optimal MS/MS spectra by searching common diagnostic ions and connecting the diagnostic ion families into a network via bridging components. This sMS(All) -based route enables identification of 71 natural products from a herbal preparation, whereas only 53 out of 71 compounds were identified using the classical DDA approach. Therefore, the sMS(All) -based approach is expected to find its wide applications for characterization of vastly diverse compounds with no priori knowledge from various complex mixtures. Copyright © 2016 John Wiley & Sons, Ltd.

Antithrombotic and antiplatelet activities of vicenin-2

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in physiological processes. However, there are limited modern data on its pharmacological effects and active components relating to its traditional use. Here, the anticoagulant and antiplatelet activities of vicenin-2 (VCN), an active compound in C. subternata, were determined. The anticoagulant activities were investigated by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). The effects of VCN on the expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-α-activated human umbilical vein endothelial cells (HUVECs). Treatment with VCN resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, VCN inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. VCN also elicited anticoagulant effects in mice. In addition, treatment with VCN resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, VCN possesses antithrombotic activities and offers a basis for development of a novel anticoagulant.

The Occurrence, Fate and Biological Activities of C-glycosyl Flavonoids in the Human Diet

The human diet contains a wide variety of plant-derived flavonoids, many of which are glycosylated via an O- or less commonly a C-glycosidic linkage. The distribution, quantity, and biological effects of C-glycosyl flavonoids in the human diet have received little attention in the literature in comparison to their O-linked counterparts, however, despite being present in many common foodstuffs. The structural nature, nomenclature, and distribution of C-glycosyl flavonoids in the human diet are, therefore, reviewed. Forty-three dietary flavonoids are revealed to be C-glycosylated, arising from the dihydrochalcone, flavone, and flavan-3-ol backbones, and distributed among edible fruits, cereals, leaves, and stems. C-linked sugar groups are shown to include arabinose, galactose, glucose, rutinose, and xylose, often being present more than once on a single flavonoid backbone and occasionally in tandem with O-linked glucose or rutinose groups. The pharmacokinetic fate of these compounds is discussed with particular reference to their apparent lack of interaction with hydrolytic mechanisms known to influence the fate of O-glycosylated dietary flavonoids, explaining the unusual but potentially important appearance of intact C-glycosylated flavonoid metabolites in human urine following oral administration. Finally, the potential biological significance of these compounds is reviewed, describing mechanisms of antidiabetic, antiinflammatory, anxiolytic, antispasmodic, and hepatoprotective effects.

Vicenin-2 and scolymoside inhibit high-glucose-induced vascular inflammation in vitro and in vivo

The vascular inflammatory process has been suggested to play a key role in the initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Thus, in this study, we attempted to determine whether 2 structurally related flavonoids found in Cyclopia subternata, vicenin-2 and scolymoside, can suppress high-glucose (HG)-induced vascular inflammatory processes in human umbilical vein endothelial cells (HUVECs) and mice. The effects of vicenin-2 and scolymoside on HG-induced vascular inflammation were determined by measuring vascular permeability, leukocyte adhesion and migration, cell adhesion molecule (CAM) expression levels, and reactive oxygen species (ROS) formation. In addition, the anti-inflammation mechanism was investigated using immunofluorescence staining and Western blotting. The data showed that HG markedly increased vascular permeability, monocyte adhesion, expression of CAMs, formation of reactive oxygen species (ROS), and activation of nuclear factor (NF)-κB. Remarkably, pretreatment with vicenin-2 and scolymoside attenuated all of the above-mentioned vascular inflammatory effects of HG. HG-induced vascular inflammatory responses are critical events underlying the development of various diabetic complications; therefore, our results suggest that vicenin-2 and scolymoside have significant therapeutic benefits against diabetic complications and atherosclerosis.

Ameliorative Effect of Aspalathin and Nothofagin from Rooibos (Aspalathus linearis) on HMGB1-Induced Septic ResponsesIn VitroandIn Vivo

The ubiquitous nuclear protein, high mobility group box 1 (HMGB1), is released by activated macrophages and human umbilical vein endothelial cells (HUVECs) and functions as a late mediator of experimental sepsis. Aspalathin (Asp) and nothofagin (Not), which have been reported to have anti-oxidant activity, are the two major active dihydrochalcones found in green rooibos. In this study, we investigated the antiseptic effects and underlying mechanisms of Asp and Not against HMGB1-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of Asp and Not were determined by measuring permeability, monocyte adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, Asp and Not effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1, and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, Asp and Not suppressed the production of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), the activation of nuclear factor-κB (NF-κB) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) by HMGB1. Collectively, these results indicate that Asp and Not could be potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.

Chemical and biological characterisation of Machaerium hirtum (Vell.) Stellfeld: absence of cytotoxicity and mutagenicity and possible chemopreventive potential

Machaerium hirtum (Vell.) Stellfeld (M.hirtum) is a plant known as 'jacarandá-bico-de-pato' whose bark is commonly used against diarrhea, cough and cancer. The aim of this study was to phytochemically characterise the hydroethanolic extract of this plant, investigate its antimutagenic activities using the Ames test and evaluate its effects on cell viability, genomic instability, gene expression and cell protection in human hepatocellular carcinoma cells (HepG2). Antimutagenic activity was assessed by simultaneous pre- and post-treatment with direct and indirect mutagens, such as 4-nitro-o-phenylenediamine (NPD), mitomycin C (MMC), benzo[a]pyrene (B[a]P) and aflatoxin B1 (AFB1), using the Ames test, cytokinesis blocking micronucleus and apoptosis assays. Only 3 of the 10 concentrations evaluated in the MTT assay were cytotoxic in HepG2 cells. Micronucleated or apoptotic cells were not observed with any of the tested concentrations, and there were no mutagenic effects in the bacterial system. However, the Nuclear Division Index and flow cytometry data showed a decrease in cell proliferation. The extract showed an inhibitory effect against direct (NPD) and indirect mutagens (B[a]P and AFB1). Furthermore, pre- and post-treated cells showed significant reduction in the number of apoptotic and micronucleated cells. This effect is not likely to be associated with the modulation of antioxidant genes, as shown by the RT-qPCR results. Six known flavonoids were identified in the hydroethanolic extract of Machaerium hirtum leaves, and their structures were elucidated by spectroscopic and spectrophotometric methods. The presence of the antioxidants apigenin and luteolin may explain these protective effects, because these components can inhibit the formation of reactive species and prevent apoptosis and DNA damage. In conclusion, the M.hirtum extract showed chemopreventive potential and was not hazardous at the tested concentrations in the experiments presented here. Moreover, this extract should be investigated further as a chemopreventive agent.

Identification and functional analysis of 2-hydroxyflavanone C-glucosyltransferase in soybean (Glycine max)

C-Glucosyltransferase is an enzyme that mediates carbon-carbon bond formation to generate C-glucoside metabolites. Although it has been identified in several plant species, the catalytic amino acid residues required for C-glucosylation activity remain obscure. Here, we identified a 2-hydroxyflavanone C-glucosyltransferase (UGT708D1) in soybean. We found that three residues, His20, Asp85, and Arg292, of UGT708D1 were located at the predicted active site and evolutionarily conserved. The substitution of Asp85 or Arg292 with alanine destroyed C-glucosyltransferase activity, whereas the substitution of His20 with alanine abolished C-glucosyltransferase activity but enabled O-glucosyltransferase activity. The catalytic mechanism is discussed on the basis of the findings.

Structural characterization of flavonoid C- and O-glycosides in an extract of Adhatoda vasica leaves by liquid chromatography with quadrupole time-of-flight mass spectrometry

RATIONALE

Adhatoda vasica Nees is a well-known Ayurvedic medicinal plant, belonging to the family Acanthaceae. This study aims to seek identification and characterization of flavonoid C- and O-glycosides in the aqueous fraction of the plant leaves.

METHODS

A method was developed for simultaneous characterization of flavonoids and their glycosides using high-pressure liquid chromatography with quadrupole time-of-flight mass spectrometry (HPLC/ESI-QTOF-MS/MS). The chromatographic separation was carried on an Agilent Poroshell 120 EC-C18 column (4.6 × 150 mm, 2.7 µm) operated with 0.1% formic acid aqueous solution and methanol as the mobile phase.

RESULTS

The fragmentations of the studied [M-H](-) ions of C-glycosides were shown to be cross-ring cleavages of the glycoside moiety [M-H-(60/90/120)](-) whereas O-glycosides were shown to eliminate the sugar moiety (Y0 (-) or [Y0 -H](-) ) from the aglycone unit; 6-C-glycosides exhibited [M-H-18](-) , a characteristic ion, and also a higher abundance of (0,3) X6 or 8 ions in comparison to 8-C glycosides; flavonoid 6,8-di-C-glycosides exhibited cross-ring cleavages of the sugar attached to the C-6 position preferentially.

CONCLUSIONS

This method was successfully applied for analysis of flavonoids and their glycosides in Adhatoda vasica leaves. A total of 29 compounds were tentatively identified including 17 C-, nine O-glycosides and three flavonoids.

Antiseptic effect of vicenin-2 and scolymoside from Cyclopia subternata (honeybush) in response to HMGB1 as a late sepsis mediator in vitro and in vivo

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, which are 2 active compounds from C. subternata that act against high mobility group box 1 (HMGB1)-mediated septic responses in human umbilical vein endothelial cells (HUVECs) and mice. The antiseptic activities of vicenin-2 and scolymoside were determined by measuring permeability, neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, vicenin-2 and scolymoside effectively inhibited lipopolysaccharide-induced release of HMGB1, and suppressed HMGB1-mediated septic responses such as hyperpermeability, the adhesion and migration of leukocytes, and the expression of cell adhesion molecules. In addition, vicenin-2 and scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6, and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by HMGB1. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Approach to the study of flavone di-C-glycosides by high performance liquid chromatography-tandem ion trap mass spectrometry and its application to characterization of flavonoid composition in Viola yedoensis

The mass spectrometric (MS) analysis of flavone di-C-glycosides has been a difficult task due to pure standards being unavailable commercially and to that the reported relative intensities of some diagnostic ions varied with MS instruments. In this study, five flavone di-C-glycoside standards from Viola yedoensis have been systematically studied by high performance liquid chromatography-electrospray ionization-tandem ion trap mass spectrometry (HPLC-ESI-IT-MS(n)) in the negative ion mode to analyze their fragmentation patterns. A new MS(2) and MS(3) hierarchical fragmentation for the identification of the sugar nature (hexoses or pentoses) at C-6 and C-8 is presented based on previously established rules of fragmentation. Here, for the first time, we report that the MS(2) and MS(3) structure-diagnostic fragments about the glycosylation types and positions are highly dependent on the configuration of the sugars at C-6 and C-8. The base peak ((0,2) X1 (0,2) X(2)(-) ion) in MS(3) spectra of di-C-glycosides could be used as a diagnostic ion for flavone aglycones. These newly proposed fragmentation behaviors have been successfully applied to the characterization of flavone di-C-glycosides found in V. yedoensis. A total of 35 flavonoid glycosides, including 1 flavone mono-C-hexoside, 2 flavone 6,8-di-C-hexosides, 11 flavone 6,8-di-C-pentosides, 13 flavone 6,8-C-hexosyl-C-pentosides, 5 acetylated flavone C-glycosides and 3 flavonol O-glycosides, were identified or tentatively identified on the base of their UV profiles, MS and MS(n) (n = 5) data, or by comparing with reference substances. Among these, the acetylated flavone C-glycosides were reported from V. yedoensis for the first time.

Effects of red palm oil and rooibos on sperm motility parameters in streptozotocin-induced diabetic rats

BACKGROUND

Diabetes mellitus characterized by hyperglycaemia could affect sperm quality as a result of increased oxidative stress. This study was performed to investigate the effects of red palm oil (RPO), aqueous rooibos tea extracts (RTE) as well as their combination (RPO + RTE) on sperm motility parameters in streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Diabetes was induced by a single administration of streptozotocin (50 mg/kg) and the rats were treated with red palm oil (2 ml/day) and / or aqueous rooibos tea extract (2%) for 7 weeks. Sperm motility parameters were measured using Computer Assisted Sperm Analyzer (CASA).

RESULTS

Hyperglycaemia negatively affected the sperm progressive motility significantly at p<0.05. There was a significant decrease (p<0.05) in sperm linearity (LIN) in the diabetic group when compared with the normal control group. RPO supplemented diabetic rats exhibited increased progressive sperm motility, sperm linearity (LIN) and wobble (WOB). Significant decreases (p<0.05) in straight line velocity (VSL) and average path velocity (VAP) of the sperms were observed in all the diabetic groups when compared to the control group. Significant (p<0.05) elevated levels of WOB and LIN were observed following RTE treatment and co-administration with RPO respectively.

CONCLUSION

The present study suggests that red palm oil and / or rooibos administration exhibited no adverse effects on sperm motility parameters but rather showed some beneficial effects.

A generic multiple reaction monitoring based approach for plant flavonoids profiling using a triple quadrupole linear ion trap mass spectrometry

Flavonoids are one of the largest classes of plant secondary metabolites serving a variety of functions in plants and associating with a number of health benefits for humans. Typically, they are co-identified with many other secondary metabolites using untargeted metabolomics. The limited data quality of untargeted workflow calls for a shift from the breadth-first to the depth-first screening strategy when a specific biosynthetic pathway is focused on. Here we introduce a generic multiple reaction monitoring (MRM)-based approach for flavonoids profiling in plants using a hybrid triple quadrupole linear ion trap (QTrap) mass spectrometer. The approach includes four steps: (1) preliminary profiling of major aglycones by multiple ion monitoring triggered enhanced product ion scan (MIM-EPI); (2) glycones profiling by precursor ion triggered EPI scan (PI-EPI) of major aglycones; (3) comprehensive aglycones profiling by combining MIM-EPI and neutral loss triggered EPI scan (NL-EPI) of major glycone; (4) in-depth flavonoids profiling by MRM-EPI with elaborated MRM transitions. Particularly, incorporation of the NH3 loss and sugar elimination proved to be very informative and confirmative for flavonoids screening. This approach was applied for profiling flavonoids in Astragali radix (Huangqi), a famous herb widely used for medicinal and nutritional purposes in China. In total, 421 flavonoids were tentatively characterized, among which less than 40 have been previously reported in this medicinal plant. This MRM-based approach provides versatility and sensitivity that required for flavonoids profiling in plants and serves as a useful tool for plant metabolomics.

Are plants used for skin care in South Africa fully explored?

ETHNOPHARMACOLOGICAL RELEVANCE

South Africa is an important focal point of botanical diversity, and although many plant species have been used since ancient times in ethnomedicine, only a few species have hitherto been fully investigated scientifically. A large proportion of the South African population use traditional medicines for their physical and psychological health needs. Many medicinal plants have recently gained popularity as ingredient in cosmetic formulations based on their ethnomedicinal values and many cosmetic products sold in stores are of natural origin. The present review discusses the ethnopharmacological values, pharmacological and toxicological evidence of 117 plant species grown in South Africa, which are used traditionally for skin care purposes. Special focus was on their traditional use for many skin disorders in order to identify their therapeutic potential, the state of ethnopharmacological knowledge and special emphasis has been on areas which require further research.

MATERIALS AND METHODS

The information regarding all 117 plant species mentioned was extracted from Sci-Finder, Science direct, Medline and Google Scholar. All the available relevant data for medicinal plants was collated from literature review articles from the 19th century to early 2013.

RESULTS

The extracts from different parts of plants exhibited significant pharmacological properties, proving significant skin care potentials. Special emphasis was on those plant species which still need further exploration and these have been documented separately.

CONCLUSIONS

Despite the immense use of plants in ethnomedicine for skin care, limited research has been done on the activity of the crude extracts and very little on the active constituents. Consequently, almost 35 out of the 117 species are totally unexplored in the area of skin care. This investigation would be of interest to a broad readership including those researchers working in this field. The plant species namely: Greyia flanaganii, Sideroxylon inerme, Sclerocarya birrea, Calodendrum capense, Hyaenanche globosa, Harpephyllum caffrum, Ximenia americana, Leucosidea sericea Artemisia afra, and six Aloe species have been scientifically validated by our research group for skin hyperpigmentation problems.

Metabolite profiling of polyphenols in peels of Citrus limetta Risso by combination of preparative high-speed countercurrent chromatography and LC-ESI-MS/MS

The polar constituents of peels from Citrus limetta variety Risso (Rutaceae) were investigated by a combination of two complementary chromatographic techniques consisting of preparative high-speed countercurrent chromatography (HSCCC), and off-line LC-ESI-MS/MS analysis to design a two-dimensional metabolite profile. Countercurrent chromatography (CCC) using solely immiscible solvent systems allowed the fractionation of principal components and an enrichment of minor concentrated metabolites from a crude polar solvent partition of C. limetta peels for subsequent structural identification by LC-ESI-MS/MS analysis. The combination of two very different chromatographic techniques resulted in lower detection limits for electrospray mass-spectrometry and revealed eighty-five compounds, including three abscisic acid derivatives, five limonoid glycosides, twenty-six dihydro-cinnamic and cinnamic acid glycosides, eleven flavanone glycosides, seven flavone glycosides, seventeen flavonol glycosides, including limocitrol and limocitrin derivatives. As a chemocharacteristic for C. limetta metabolites, many of the detected structures were linked to single and multiple 3-hydroxy-3-methyl-glutaryl (HMG) substitutions. C. limetta peels are a by-product of juice production, and not only the antioxidant fractions but also some of the fortified compounds could be used for food and pharmaceutical purposes.