Luteolin Glycosides Research Articles

Glycosylation of luteolin in hydrophilic organic solvents and structure-antioxidant relationships of luteolin glycosides.

An effective approach was developed to biotransform luteolin glycosides in hydrophilic organic solvents. Bacillus cereus A46 cells showed high activity and stability in 5–20% (v/v) DMSO with 90–98% conversion rates of luteolin glycosides. Five glycosides of luteolin 7-O-β-glucoside, luteolin 4′-O-β-glucoside, luteolin 3′-O-β-glucoside, luteolin 7,3′-di-O-β-glucoside and luteolin 7,4′-di-O-β-glucoside were obtained. The addition of DMSO greatly promoted the solubility of luteolin and further regulated the formation of the main products from five luteolin glycosides to luteolin 7-O-β-glucoside (931.2 μM). Fourteen flavonoids and anthraquinones were used as tentative substrates. Glycosylation positions were located at the C-7, C-3′ or C4′ hydroxyl groups of flavonoids and C-5 hydroxyl group of anthraquinones. The 3′,4′-dihydroxy arrangement played the key role for the antioxidant activity of luteolin.

Photoreactivity and stability of flavonoid yellows used in cultural heritage

Flavonoid yellows are historical dyes widely found in cultural heritage, in particular those based on the glycosides of luteolin, quercetin and kaempferol. In this research, for the first time, the photodegradation quantum yields (ΦR) were calculated for luteolin, quercetin and kaempferol as well as their glycosides Lut-7-O-Glc, Que-3-O-Glr, Kaem-3-O-Glc and compared to the reactivity of eriodictyol. The results are discussed within the current state of the art on the mechanisms of degradation for these antioxidant compounds, which are reviewed in the introduction. ΦR values were obtained in solution irradiating at 313 nm and 366 nm, providing the quantification of the stability of flavonoid yellows. In particular, by irradiating at 366 nm, a very good stability scale is obtained, with ΦR values for luteolin and the 3-O-glycosides of quercetin and kaempferol on the order of 10−6. The more reactive quercetin and kaempferol are characterized by ΦR values of ca. 3 × 10−5. The relative stability of these yellows can be explained by a photoprotective mechanism based on excited state proton transfer, which is more efficient when there is an OH in the C5 position. In addition, electron transfer, and consequently oxidation, is also enhanced through the OH in position C3 when compared to C5.Solvents effects were also studied and to mimic the environment of the dye in wool, irradiation at 366 nm in a proteinaceous gel was carried out. In this gel, the ΦR values increased for all the molecules studied, reaching 1 × 10−4 and 2 × 10−4 for kaempferol and quercetin, respectively. This drastic enhancement shows that the environment has a major impact on stability. The main degradation products were also studied by irradiation with a xenon source (λirr ≥ 300 nm), and characterized by HPLC-DAD-MS and LC-HRMS/MS. These data, on the reaction mechanism, show that the double bond between C2 and C3, in the C ring, is the most reactive point of the molecules, as in all the flavonoids degradation started by solvent attack, followed in some cases by ring opening and the formation of low molecular weight hydroxyl compounds such as benzoic acids, in agreement with the general reaction scheme proposed in literature.

THE CHEMICAL COMPOSITION OF THE FRACTIONS OF THE AERIAL PART OF CULTIVATED CHICORY AND THEIR ANTIOXIDANT ACTIVITY

Chicory (Cichorium intybus L.) is a biennial or perennial herb of the Asteraceae family, growing in the Russian Federation under natural conditions in meadows, forest glades, grassy slopes, as well as on wastelands, fields, overgrown dumps and roadsides. Along with the wild-growing chicory, breeding varieties of cultivated plants are also known, intended for obtaining roots, while the aboveground part, which is a root rosette of leaves, is a production waste.
 The purpose of this study was to study the qualitative composition and antioxidant properties of biologically active substances (BAS) of the aerial part of cultivated chicory and to assess the potential for using secondary raw materials of this plant in the pharmaceutical industry for obtaining medicines.
 As a result of the study by HPLC-UV-MS / MS, it was found that the phenolic complex of the aerial part of the cultivated chicory is represented by phenol carboxylic acids - esters of caffeic, ferulic, coumaric acids with organic acids (quinic and tartaric) in various combinations; trace amounts of oxycoumarins (chicoriin); flavonoids (glycosides of quercetin, luteolin and isorhamnetin).
 The study of the antioxidant properties of BAS fractions of different polarity showed that the ethyl acetate fraction has the highest activity. It was found that the main dominant compound of this fraction is cichoric acid, which suggests that it is this metabolite that makes a decisive contribution to the antioxidant activity of the fraction and the extract as a whole.

Phytochemical composition and biological screening of two Lophophytum species

Lophophytum species are holoparasites that grow on tree roots. The objectives of the work were to explore the chemical composition of the tubers of two Lophophytum species and to analyze the antioxidant, anti-inflammatory and antilithiatic activity of their extracts using in vitro methods. The chemical composition was determined by histochemical, phytochemical and TLC tests. In addition, the profile of phenolic compounds was determined by HPLC-MS. The presence of secondary metabolites of recognized activity was demonstrated. The results of the HPLC-MS/MS allowed the tentative identification of catechin, luteolin and glycosides of eriodictyol, naringenin and luteolin in the extract of Lophophytum leandri and eriodictyol, naringenin, luteolin and their glycosylated derivatives in Lophophytum mirabile. The extracts showed promising antioxidant (DPPH, ABTS and β-carotene-linoleic acid), anti-inflammatory (inhibition of 5-LOX) and anti-urolytic (by bioautographic TLC) activity. It is noteworthy that these are the first results of the phytochemical composition and biological activity of L. mirabile. However, in vivo studies are required to corroborate these activities.

Chemical Composition of Hypericum Coadunatum Chr. from the Canary Islands

Extensive phytochemical analysis of the aerial part of H. coadunatum, a rare insular endemism of the Canary Islands, has resulted in the isolation and identification of several metabolites of diverse classes with interesting biological properties. Examples include flavonoids, luteolin and apigenin glycosides, quercetin and kaempferol glycosides, xanthones, phloroglucinols and other common metabolites. The flavone glycoside, 8-C-β-L- arabinopiranosylapigenin 5 and its hexaacetate 5a are described here for first time. A conformational analysis of orientin octaacetate was carried out using molecular mechanics (PCMODEL 9.2, MMX force field). The structures of the compounds were elucidated on the basis of spectroscopic analysis, viz. 1D and 2D NMR experiments, chemical study, and comparison with literature data.

Inhibitory effects of luteolin and its derivatives on osteoclast differentiation and differences in luteolin production by Capsicum annuum varieties.

Luteolin, an abundant flavonoid in the leaves of Capsicum annuum, has antioxidant activity and is, thus, a key chemical for promoting plant residue utilization, especially for the development of healthcare products. We assessed the inhibitory effect of luteolin and its glycosides on osteoclastic differentiation in human cells and found that the differentiation was effectively inhibited at noncytotoxic concentrations. We also screened 47 varieties of C. annuum for the accumulation of luteolin and apigenin to determine the prevalence of luteolin in diverse cultivars and identify varieties with high and/or selective luteolin production. The glycosides of luteolin and apigenin were found in all the tested varieties, with luteolin predominant over apigenin in most varieties. The identification and characterization of highly productive varieties of C. annuum is expected to be beneficial for the effective development of useful luteolin-based products from plant residues.

Impact of Moderate Cold and Salt Stress on the Accumulation of Antioxidant Flavonoids in the Leaves of Two Capsicum Cultivars.

The horticultural production of bell peppers generates large quantities of residual biomass. Abiotic stress stimulates the production of protective flavonoids, so the deliberate application of stress to the plants after fruit harvest could provide a strategy to valorize horticultural residuals by increasing flavonoid concentrations, facilitating their industrial extraction. Here we exposed two Capsicum cultivars, a chilli and a bell pepper, to cold and salt stress and combinations thereof to determine their valorization potential. Noninvasive image-based phenotyping and multiparametric fluorescence measurements indicated that all stress treatments inhibited plant growth and reduced the leaf chlorophyll fluorescence index, with the chilli cultivar showing greater sensitivity. The fluorescence-based FLAV index allowed the noninvasive assessment of foliar luteolin glycosides. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis showed that moderate cold increased the levels of two foliar antioxidant luteolin glycosides in both cultivars, with bell pepper containing the highest amounts (induced to maximum 5.5 mg g-1 DW cynaroside and 37.0 mg g-1 DW graveobioside A) after combined stress treatment. These data confirm the potential of abiotic stress for the valorization of residual leaf biomass to enhance the industrial extraction of antioxidant and bioactive flavonoids.

Whole cell biosynthesis of luteolin glycosides by engineered Corynebacterium glutamicum harboring the amylosucrase gene

The transglycosylation activity of Deinococcus geothermalis amylosucrase (DgAS) expressed in Corynebacterium glutamicum (cDgAS) was optimized for luteolin glycoside synthesis using purified enzymes (PEs), whole cells (WCs) suspended in buffer (WCB) and WCs in ethanol (WCE). Unlike PE, both WCB and WCE had high transglycosylation yields exceeding 95% over a wide temperature range, with cells in ethanol exhibiting the greatest enzymatic activity for up to 48 h due to membrane degradation and the slow release of cDgAS, which led to lysis and death. Meanwhile, in buffer, protection of the cytoplasmic membrane and ideal pH conditions maintained activity for over 200 h. To improve their performance, WCs were immobilized on agarose and the resulting immobilized cells (ICs) had high stability in organic solvents, although WCB possessed greater thermal stability at 50 °C. The reaction parameters for PE, WCE, WCB, and IC transglycosylation were optimized using response surface methodology, and ICs required lower concentrations of substrates while synthesizing higher concentrations of reaction products in addition to producing the novel compound luteolin maltotrioside after several cycles of reuse. This study expanded on the range of possibilities for the industrial application of C. glutamicum in increasing the production and bioavailability of novel and improved products.

Effects of ammonium levels on growth and accumulation of antioxidative flavones of the submerged macrophyte Ceratophyllum demersum

Field data on the occurrence of the common and cosmopolitan submerged macrophyte Ceratophyllum demersum in relation to the water ammonium content were compared with the response of the plants to different ammonium treatments performed in the laboratory. Ammonium concentrations above 10 μM in the monitored area were found to be a strong limiting factor on the presence of C. demersum in water bodies. On the other hand, no adverse effect of nitrate was observed. In short-term laboratory experiments, the plants grew well even at 100 μM ammonium at pH 7.5, but higher concentrations affected the plant. Laboratory experiments showed that the accumulation of flavonoids with antioxidant properties was induced by ammonium. The detailed LC/MS analysis of the major flavonoids showed that the most abundant compound was tricetin present mainly as a monoglycoside in crude extracts. Luteolin, selgin, apigenin, tricin and chrysoeriol glycosides were also present in considerable amounts. Tricetin, a flavonoid having strong antioxidative properties, was most induced by higher ammonium levels. At high ammonium concentrations, plant tissues exhibited notable damage and the production of antioxidants declined.

In vitro antiplatelet activity of extract and its fractions of Paulownia Clone in Vitro 112 leaves

BackgroundPaulownia Clone in Vitro 112, also known as Oxytree is a hybrid of Paulownia elongata and Paulownia fortunei, developed under laboratory conditions. Its seeds are sterile, making it a noninvasive variety that can only be propagated in the laboratory. In China, species from the Paulownia genus (Paulowniaceae) are widely used in traditional medicine for the treatment of infectious diseases, such as gonorrhea and erysipelas. It has a broad spectrum of bioactivity, including neuroprotective, antioxidant, antibacterial, antiphlogistic, antiviral, and cytotoxic actions. However, the antiplatelet potential of Paulownia Clone in Vitro 112 has not yet been described. Study designThe aim of our study was thus to examine the effect of an extract and four fractions from leaves of Paulownia Clone in Vitro 112 on various parameters of platelet activation in an in vitro model. MethodsComposition of the investigated extract and fractions was determined by UHPLC-UV-MS. The following parameters of platelet activation were investigated: nonenzymatic lipid peroxidation in resting platelets; enzymatic lipid peroxidation (AA metabolism) in platelets activated by thrombin; superoxide anion (O2−.) generation in the resting and activated platelets; platelet adhesion to collagen type I and fibrinogen; platelet aggregation stimulated by various physiological agonists, such as ADP, collagen, and thrombin. The effect of the extract and fractions on extracellular LDH activity, a marker of cell damage, was also determined. ResultsVerbascoside a phenylethnanoid glycoside, was the main secondary metabolite of the extract from leaves of oxytree (constituting approximately 45 % of all compounds). There were also iridoids, such as catalpol, aucubin, and 7-hydroxytomentoside, as well as flavonoids, such as luteolin and apigenin glycosides. Moreover, the extract had stronger antiplatelet properties than the fractions. For example, the extract at 10 μg/mL inhibited five parameters of platelet activation. ConclusionsOur results show that Paulownia Clone in Vitro 112 leaves are a new valuable source of compounds with antiplatelet potential.

Comparative effects of quercetin, luteolin, apigenin and their related polyphenols on uric acid production in cultured hepatocytes and suppression of purine bodies-induced hyperuricemia by rutin in mice.

Hyperuricemia, the high uric acid (UA) state in blood, has been accepted as an important risk factor for gout. The liver is a main factory of UA production. In the present study, we have examined the effects of three kinds of flavonol and flavones as typical aglycons, i.e., quercetin, luteolin, apigenin, their glycosides and related compounds, on UA productivity in cultured hepatocytes, adopting allopurinol as the positive control drug. Quercetin, luteolin, diosmetin (4'-O-methylluteolin) and apigenin at 10, 30 and 100μM as well as allopurinol at 0.1, 0.3 and 1μM dose-dependently and significantly decreased UA production in the hepatocytes, when compared with 0μM (control). Both rutin (quercetin-3-O-rutinoside) and quercitrin (quercetin-3-O-ramnoside) significantly reduced UA production in the hepatocytes at 100μM. Luteolin glycosides such as orientin (luteolin-8-C-glucoside) and isoorientin (luteolin-6-C-glucoside) exerted no influences on it even at 100μM. Likewise, apigenin glycosides such as vitexin (apigenin-8-C-glucoside) and isovitexin (apigenin-6-C-glucoside) showed no inhibitory effect on it, while apigetrin (apigenin-7-O-glucoside) significantly reduced it at 100μM. In model mice with purine bodies-induced hyperuricemia, allopurinol completely suppressed the hyperuricemia at a dose of 10mg/kg body weight. Rutin suppressed significantly the hyperuricemia at a dose of 300mg/kg body weight, while vitexin showed no significant effect up to 300mg/kg body weight. Thus, rutin (O-glycoside) is demonstrated to be hypouricemic in both cultured hepatocytes and model mice with recently contrived purine bodies-induced hyperuricemia.

ECDYSTEROIDS AND GLYCOSYLFLAVONES OF SILENE SIBIRICA (CARYOPHYLLACEAE)

The present work realized the chemical study of Silene sibirica (L.) Pers. (Caryophyllaceae) high-performance liquid chromatography with diode array and mass spectrometric detection (electrospray ionization) (HPLC-DAD-ESI-MS). As a result, 25 compounds were found, including nine ecdysteroids and sixteen flavonoids. Ecdysteroids components were podecdysone C, integristerone A, turkesterone, polypodine B, 20-hydroxyecdysone and its 2-O-cinnamate, ecdysone, 2-deoxy-20-hydroxyecdysone, and 2-deoxyecdysone. Flavonoids were the glycosylflavones and derivatives of luteolin and apigenin. Luteolin glycosides included luteolin-7-O-rutinoside, lucenin-2, carlinoside, isoorientin and its 2″-O-arabinoside, as well as isoscoparin. The largest group of apigenin glycosides included O-glycosides as 7-O-glucoside and 7-O-rutinoside, C-glycosides as isovitexin, schaftoside, vicenin-2, and mixed C,O-glycosides as isovitexin-2′′-O-arabinoside and 2′′-O-rhamnoside. Three unidentified derivatives of apigenin were pre studied and their structural features discussed. Quantitative data about the content of selected compounds indicated that ecdysteroids accumulated in S. sibirica flowers (7.14–14.92 mg/g) and glycosylflavones were found predominantly in leaves (7.88–18.55 mg/g). The major ecdysteroid compound was 20-hydroxyecdysone, while flavonoids predominants were shaftoside and isovitexin-2″-O-ramnoside. A comparative analysis of the chemical composition of wild-growing and cultivated S. sibirica samples showed the stability of the metabolic profile of the plants during the introduction. The biological studies revealed the antiradical and antiglucosidase activity of the extracts. Thus, it was shown that the studied plant species (S. sibirica) is a source of ecdysteroids and glycosylflavones, and S. sibirica extracts have biological potency.

Antioxidant and Anti-Inflammatory Activities in Relation to the Flavonoids Composition of Pepper (Capsicum annuum L.).

The chili pepper (Capsicum annuum L.) is a food source that is rich in flavonoids such as luteolin and apigenin. Flavonoids are known to have anti-inflammatory and antioxidant activities; however, studies on the flavonoids composition identified and the anti-inflammatory and antioxidant effects in pepper leaves (PL) and fruits (PF) are insufficient. In the present study, we investigated the antioxidant and anti-inflammatory effects in vitro, and the flavonoids contents of the PL and PF. Pepper extracts showed radical scavenging activities and ameliorated the lipopolysaccharide (LPS)-stimulated inflammatory response by decreasing nitric oxide production and interluekin-6 and tumor necrosis factor alpha levels in RAW 264.7 cells, with more effective activities noted for PL than for PF. Furthermore, PL extracts markedly inhibited the LPS-induced production of reactive oxygen species accumulation. The flavonoid profile and content of pepper were dependent on the part, with PL showing higher total flavonoids than PF. In particular, the content of luteolin glycosides in PL was twice that in PF. Thus, PL may be useful to prevent oxidative stress and inflammation-related diseases.

Health-Promoting Effects of Thymus Phenolic-Rich Extracts: Antioxidant, Anti-Inflammatory and Antitumoral Properties.

Thymus genus comprises numerous species that are particularly abundant in the West Mediterranean region. A growing body of evidence suggests that many of these species are a rich source of bioactive compounds, including phenolic compounds such as rosmarinic acid, salvianolic acids and luteolin glycosides, able to render them potential applications in a range of industrial fields. This review collects the most relevant studies focused on the antioxidant, anti-inflammatory and anti-cancer of phenolic-rich extracts from Thymus plants, highlighting correlations made by the authors with respect to the main phenolic players in such activities.

Development of Methods of Analysis of Biological Active Substances for Standardization of Dense Extract of Creeping Thyme

Pharmaceutical development of mucolytic agent with dense extract of creeping thyme and essential oil of thyme involves obtaining a dense thyme extract of creeping, that is, choosing of optimal conditions that will allow in a short time to obtain a dense extract enriched with the main biological active substances (BAS) - which is a resultant extract and finished drug. Since in the analysis of creeping thyme herb in order to standardize this raw material as a quality index, among others, we chose the composition of flavonoids and hydroxycinnamic acids and the quantitative content of flavonoids, then it is appropriate to study the qualitative and quantitative composition of these bioactive substances and in the obtained extract. The aim of our work was to develop methods of analysis of BAS for the standardization of dense extract of creeping thyme; Identification and determination of the quantitative content of the analyzed biological active substances in herbal medicinal products and their respective extracts were carried out using modern sensitive and selective methods of analysis (thin-layer chromatography, differential spectrophotometry); As a result of TLC, the presence of fructose, glucose, arabinose, xylose, and rhamnose were found in the dense creeping thyme extract. According to the ratio of the size and intensity of staining on the chromatograms, it has been concluded that the predominant monosaccharide is fructose, and from the reducing monosaccharides - glucose, which will allow them to choose markers of the quality of the test extract. We also identified tyrosine, alanine, leucine, glycine, glutamic and aspartic acids at the levels of the respective zones on the chromatogram of the comparison solution. Chromatographic studies of a dense extract of creeping thyme by the thin-layer chromatography method have allowed identifying phenol carboxylic acids – rosmarinic (main representative), caffeic and chlorogenic; flavonoids – luteolin-7-O-glucoside, apigenin-7-O-glucoside, luteolin, apigenin, and rutin. Two acids were not identified, small quantities of which are found in the upper part of a chromatogram and of the unidentified structure of luteolin glucoside, which, by size and intensity of fluorescence, are not the main representative of flavonoids in the extract. Based on the literature, this representative of flavonoids may be Luteolin-7-O-di or triglycoside; Qualitative composition of a dense extract of creeping thyme herb in BAS groups – flavonoids, amino acids, polysaccharides has been studied. In order to standardize the extract, identification markers from phenolic compounds – luteolin-7-O-glucoside, luteolin, rutin, chlorogenic, rosmarinic, and caffeic acids, luteolin glycoside of unknown composition has been proposed. The quantitative content of flavonoids, amino acids, and reconstructive monosaccharides in the dense extract has been investigated. The correlation of content of the main BAS groups for dense extract indicates that the selected conditions for transferring the liquid extract to the dense are correct. When standardizing the dense extract of creeping thyme by the flavonoid content is proposed to be at least 2.5% in terms of apigenin.

Anticancer activity of luteolin glycosides.

Anticancer activity of luteolin glycosides.

Changes in chemical compositions of Chrysanthemi Flos after frying and protective effects on CCl_4-induced acute liver injury in mice

To reveal the processing mechanism of Chrysanthemi Flos from the changes of chemical compositions after frying and its effect on the efficacy of liver protection. Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry(UPLC-Q-TOF-MS) and ultra high performance liquid chromatography(HPLC) were used for the qualitative and quantitative researches of chemical compositions before and after Chrysanthemi Flos frying. Progenesis QI and SPSS software were used for principal component analysis(PCA), partial least squares discriminant analysis(PLS-DA), variable importance projection(VIP) analysis and t-test to identify the compositions with significant changes. Pharmacodynamics experiment was used to investigate the protective effect of crude and fried Chrysanthemi Flos on CCl_4-induced acute liver injury in mice. According to mass spectrometry data, there were 28 chemical compositions in crude and fried Chrysanthemi Flos, mainly including flavonoids and organic acids. 13 compositions such as luteolin, apigenin and luteolin glycoside were increased significantly after frying, while 7 compositions such as chlorogenic acid, luteolin-7-O-glucuronide and apigenin-7-O-glucuronide were decreased significantly after frying. Through principal component analysis, crude and fried Chrysanthemi Flos products were divided into two categories, indicating that there were internal differences in quality. The results of liver injury protection experiment in mice showed that the AST, ALT and MDA contents were significantly decreased and SOD level was increased in mice with liver injury in both the high and medium dose groups. Histopathological examination showed that crude and fried Chrysanthemi Flos can protect the liver by reducing inflammatory cell infiltration, reducing steatosis, and repairing damaged liver cells. The results of this study showed that the chemical compositions had obvious changes after frying, and both crude and fried Chrysanthemis Flos had protective effects on CCl_4-induced acute liver injury in mice. In addition, in the range of high, medium and low doses, the liver protection effect of crude and fried Chrysanthemi Flos increased with the increase of dose. The experiment results provided reference for the mechanism of fried Chrysanthemi Flos and clinical selection of processed products.

Impact of different extraction solvents and techniques on the biological activities of Cirsium yildizianum (Asteraceae: Cynareae)

Several Cirsium species have been used in folk medicine for the management of human ailments. However, there is a paucity of scientific data regarding their biological activity as in the case of the new species, C. yildizianum, from Anatolia, Turkey. The present study endeavours for the first time to appraise the antioxidant and enzyme inhibitory activity of C. yildizianum. The phytochemical profiles of C. yildizianum extracts obtained using homogeniser-assisted extraction (HAE), ultrasound-assisted extraction (UAE), Soxhlet extraction, maceration, decoction, and infusion, using methanol or water as extraction solvents, was determined by high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC–ESI-MSn) analysis. In all extracts, flavonoids were the most abundant compounds, particularly luteolin and apigenin glycosides. HAE methanol extract presented the highest phenolic (37.10 mg gallic acid equivalent/g) and flavonoid (46.78 mg rutin equivalent/g) contents. Likewise, HAE-methanol extract showed potent radical scavenging (40.76 and 68.13 mg Trolox equivalent [TE]/g, for DPPH and ABTS, respectively) and reducing properties (127.62 and 89.95 mg TE/g, for CUPRAC and FRAP, respectively). HAE-methanol extract showed inhibitory activity against acetylcholinesterase (AChE) (3.57 mg galantamine equivalent [GALAE]/g). UAE-methanol extract was a potent inhibitor of butrylcholinesterase (BChE) (2.72 mg GALAE/g) and tyrosinase (121.06 mg kojic acid equivalent/g) However, poor inhibition was recorded for enzymes targeted in the management of diabetes type II, namely α-amylase and α-glucosidase. On the other hand, potent metal chelating property was observed for water extracts. This study provides comprehensive scientific information on the phytochemical profile of C. yildizianum extracted using different procedures and extraction solvents, which might be considered as valuable baseline data for future bioproducts development.

Antioxidant content and identification of phenolic/flavonoid compounds in the pollen of fourteen plants using HPLC-DAD

This study was carried out to evaluate the in vitro potential antioxidant activity, total phenolics, flavones, and flavonol content of hydro-ethanolic extracts of pollen from fourteen plants belonging to ten families. The identification of phenolic and flavonoid compounds was accomplished using HPLC-DAD analysis. The results of the total phenolic contents varied from 9.20 ± 0.12 mg GAE (Gallic acid equivalent)/g in the pollen sample of Malva sylvestris, to 71.20 ± 0.72 mg GAE (Gallic acid equivalent)/g in the pollen of Mentha spicata, while flavones and flavonols content ranged from 1.27 ± 0.07 mg QE (Quercetin equivalent)/g in the pollen of Scolymus hispanicus to 15.44 ± 1.14 mg QE (Quercetin equivalent)/g in the pollen samples collected from Anacyclus radiatus. The total antioxidant capacity assessed using the molybdate assay ranged between 17.84 ± 1.03 mg AAE (ascorbic acid equivalent)/g in Malva sylvestris to 99.54 ± 0.90 mg AAE (ascorbic acid equivalent)/g in Capparis spinosa pollen. Concerning antioxidant ability, Mentha spicata and Mentha pulegium had the best antioxidant ability. The HPLC-DAD analysis showed a wide variety of flavonols and flavones, mainly glycosides of apigenin, luteolin, kaempferol, quercetin, and isorhamnetin. The phenolic acids are represented by derivatives of caffeic acid, p-hydroxybenzoic acid, and vanillic acid. In Malva sylvestris and Scolymus hispanicus some compounds found could be alkaloids, however, in this work the confirmation of such chemical group was not carried out but it will be included in further studies.

Influence of leaf temperature and blue light on the accumulation of rosmarinic acid and other phenolic compounds in Plectranthus scutellarioides (L.)

In this study, the influence of different lamp types on physiology and secondary metabolites of Plectranthus scutellarioides (Solenostemon scutellarioides, Coleus blumei) was examined. The following four lamp systems were tested: a new microwave plasma lamp (MPL) emitting artificial sunlight, a commercial high-pressure sodium lamp (HPS), a ceramic metal halide lamp (CDM), and light-emitting diodes (LEDs). The lamps differed not only in the spectral properties of the emitted light but also in the emission of infrared radiation. The aim of this study was to investigate both the influence of the spectral quality and the influence of the leaf temperature from four different lamp systems on morphology and secondary metabolites in P. scutellarioides. Total phenolic compounds were quantified with colorimetric methods. For detailed description of the phenolic compounds, qualitative and quantitative analysis of selected phenolic compounds were performed by HPLC.Stem elongation was increased in plants grown with MPL and LED light, which was attributed to the higher amount of far-red light in the emission spectra. On the other hand, higher infrared radiation from MPL and HPS lamps led to increased leaf temperatures compared to plants grown with LED or CDM light, resulting in faster plant development indicated by greater leaf pair formation. In addition to rosmarinic acid (RA), which is typical for members of the family Lamiaceae, luteolin and apigenin glycosides were detected by mass spectrometry. The results demonstrated that P. scutellarioides leaves contained three acylated cyanidin diglycosides, one of them containing just a coumaroyl residue, the other two containing one and two additional malonyl residues, whereby malonylated compounds appeared in higher quantities. Leaves grown with LED and CDM light contained the highest amount of RA and flavone glycosides per dry weight, which was attributed to a lower leaf temperature compared to leaves developed under MPL or HPS light. Further, an increased blue light content in the emission spectra led to thicker leaves and consequently to a higher accumulation of secondary metabolites per leaf area.