Apigenin Derivatives Research Articles

Chemical composition of hydroethanolic extracts from Siparuna guianensis, medicinal plant used as anxiolytics in Amazon region

Siparuna guianensis Aubl., Siparunaceae, is used as anxiolytic plants in folk medicine by South-American indians, caboclos and river-dwellers. This work focused the evaluation of phenolic composition of hydroethanolic extract of S. guianensis through HPLC-DAD-ESI/MS/MS. The constituents exhibited protonated, deprotonated and sodiated molecules and the MS/MS fragmentation of protonated, deprotonated and sodiated molecules provided product ions with rich structural information. Vicenin-2 (apigenin-6,8-di-C-glucoside) was the main constituent found in S. guianensis together quercetin-3,7-di-O-rhamnoside and kaempferol-3,7di-O-rhamnoside. A commercial extract of Passiflora incarnata (Phytomedicine) was used as surrogate standard and also was analyzed through HPLC-DAD-ESI/ MS/MS, showing flavones C-glycosides as constituents, among them, vicenin-2 and vitexin. The main constituent was vitexin. Flavonols triglycosides was also found in low content in S. guianensis and were tentatively characterized as quercetin-3O-rutinoside-7-O-rhamnoside, quercetin-3-O-pentosyl-pentoside-7-O-rhamnoside and kaempferol-3-O-pentosyl-pentoside-7-O-rhamnoside. Apigenin and kaempferol derivatives had been reported as anxiolytic agents. Flavonoids present in this extract were correlated with flavonoids reported as anxiolytics.

Nutrients, phytochemicals and bioactivity of wild Roman chamomile: A comparison between the herb and its preparations

Roman chamomile, Chamaemelum nobile L. (Asteraceae), has been used for medicinal applications, mainly through oral dosage forms (decoctions and infusions). Herein, the nutritional characterisation of C. nobile was performed, and herbal material and its decoction and infusion were submitted to an analysis of phytochemicals and bioactivity evaluation. The antioxidant activity was determined by free radicals scavenging activity, reducing power and inhibition of lipid peroxidation, the antitumour potential was tested in human tumour cell lines (breast, lung, colon, cervical and hepatocellular carcinomas), and the hepatotoxicity was evaluated using a porcine liver primary cell culture. C. nobile proved to be an equilibrated valuable herb rich in carbohydrates and proteins, and poor in fat, providing tocopherols, carotenoids and essential fatty acids (C18:2n6 and C18:3n3). Moreover, the herb and its infusion are a source of phenolic compounds (flavonoids such as flavonols and flavones, phenolic acids and derivatives) and organic acids (oxalic, quinic, malic, citric and fumaric acids) that showed antioxidant and antitumour activities, without hepatotoxicity. The most abundant compounds in the plant extract and infusion were 5-O-caffeoylquinic acid and an apigenin derivative. These, as well as other bioactive compounds, are affected in C. nobile decoction, leading to a lower antioxidant potential and absence of antitumour potential. The plant bioactivity could be explored in the medicine, food, and cosmetic industries.

Cytotoxic Apigenin Derivatives from Chrysopogon aciculatis

Four new apigenin derivatives, 7-de-O-methylaciculatin, 8-C-β-D-boivinopyranosylapigenin, aciculatinone, and 4'-O-glucosylaciculatin, along with eight known compounds, apigenin-8-carbaldehyde, kaempferol, tricin, taxifolin, 6,7,4'-trihydroxyflavone, trans-oxyresveratrol, aciculatin, and luteolin-7-sulfate, were isolated from an ethanolic extract of Chrysopogon aciculatis. Their chemical structures were elucidated by spectroscopic methods. Among the known compounds, the natural occurrence of apigenin-8-carbaldehyde and luteolin-7-sulfate is demonstrated for the first time. Some of the isolates were evaluated for cytotoxic activity against human cancer cell lines including MCF-7, H460, HT-29, and CEM.

Volatile and non-volatile compounds and antimicrobial activity of Mansoa difficilis (Cham.) Bureau & K. Schum: (Bignoniaceae)

Essential oil from the leaves of Mansoa difficilis was analyzed by GC/MS. Oct-1-en-3-ol (49.65%) was the major compound, but diallyl di- and trisulfide were also present (0.85 and 0.37%, respectively), justifying the garlic-like odor of the crushed leaves. The hexane and methanol extracts of the leaves and stems afforded as main constituents a mixture of linear hydrocarbons, spinasterol, stigmasterol, ursolic and oleanolic acids, two apigenin derivatives and verbascoside. The hexane and methanol extracts of leaves were tested for antimicrobial activity against ten microorganisms. The hexane extract was active against both Psedomonas aeruginosa and Staphylococcus aureus.

Accumulation of phenylpropanoids in green and red pepper fruits of semi-hot cultivars Capsicum annuum L.

The aim of the present work was to determine differences in <i>C</i> and <i>O</i> glycosides of flavonoids, derivatives of phenolic acids, as well as capsaicinoid content in two semi-hot pepper cultivars, cv. Tornado and Tajfun. Fruits were harvested at the green and red maturity stages. Flavonoid and capsaicinoid fractions were isolated on Sep-Pak C18 cartridges with 40% and 70% methanol-water solutions, respectively. The chemical composition of both fractions was determined by HPLC method using standards of phenolic compounds obtained in the earlier work and the capsaicin standard. The flavonoid fraction contained glucose esters of phenolic acid, mainly ferulic and sinapic acid, as well as derivatives of flavonoids, quercetin, luteolin and apigenin, which occurred as <i>O</i>- and <i>C</i>- glycosides with glucose, rhamnose, and apiose. The capsaicinoid fraction contained mainly capsaicin and dihydrocapsaicin. It was found that in green fruits flavonoid <i>O</i>-glycosides were the predominant phenolics, while in red ones derivatives of phenolic acids. A higher loss of <i>O</i>-glycosides of flavonoids than of <i>C</i>-glycosides was observed during the maturation of the fruit of semi-hot pepper cultivars.

Isolation of 3 Flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia and Determination of Their Genotoxic Potentials by Using the E. coli WP2 Test System

Flavonoids, abundant in most of plant species, are widely used in medicine and development studies on phytotherapeutic drugs due to their various biological activities. In the present study, 3 flavonoids, apigenin-7-O-glucoside, apigenin-7-O-rutinoside, and apigenin-7-O-glucuronide, were isolated from Mentha longifolia (L.) Hudson subsp. longifolia by using E. coli WP2 genotoxicity assay guided fractionation procedures. Later, the mutagenic and antimutagenic properties of each flavonoid were evaluated by using the same genotoxicity assay. The results showed that all the test compounds have significant antimutagenic activity at tested concentrations with or without S9 activation. The inhibition rates were between 25.3% (apigenin-7-O-glucoside with S9-2.0 μM/plate) and 59.0% (apigenin-7-O-rutinoside without S9-2.0 μM/plate). In conclusion, the results revealed that the 3 flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia have significant antimutagenic activity, and the findings of the present study are valuable for further investigations, focus on the phytotherapeutic drug discovery. Apigenin derivatives can be thought as genetically safe at tested concentrations because they did not show mutagenic activity. Furthermore, they have also significant antimutagenic activity. These are valuable for further research focus on phytotherapeutic drug discovery and development.

Secondary metabolites from Potentilla recta L. and Drymocallis rupestris (L.) Soják (syn. Potentilla rupestris L.) (Rosaceae)

► The isolation of polyphenolics from Potentilla recta and Drymocallis rupestris were carried out. ► All compounds from P. recta and D. rupestris were isolated for the first time. ► The occurrence of flavones based on apigenin and luteolin derivatives from Potentilla species has never been reported so far. ► This is the first report of the chemical composition of aerial parts of D. rupestris . ► Isolated compounds could be chemotaxonomic markers for the genus Potentilla .

Variation of polyphenols in a germplasm collection of globe artichoke

Globe artichoke, a crop native to the Mediterranean Basin, is rich in polyphenols whose health-promoting properties have been well documented in literature. Here, we reported the variation of polyphenol content and antioxidant activity in plant parts (floral stem, receptacle, inner and outer bracts) of 17 cultivars. Our objectives were also to evaluate the influence of harvest time (winter and spring) on total polyphenol content and to assess the polyphenol composition by HPLC in six cultivars not previously analysed. The total content and profile of polyphenols were significantly different amongst cultivars and plant parts. ‘Tema 2000’, ‘Nobre’ and ‘Violetto di Sicilia clone 4/8’ had the highest level of total polyphenol content, whilst ‘Camerys’ and ‘Tempo’ had the lowest. Polyphenols resulted more abundant in the floral stem and receptacle. These were, respectively, rich in caffeoylquinic acids and apigenin derivatives. Each cultivar preferentially accumulated polyphenols in specific plant parts and, hence, may have a specific end-use based on its polyphenol content. In this view, the high level of total polyphenols in the receptacles of ‘Tema 2000’, ‘Opal’ and ‘Nobre’ makes them more suitable for the fresh consumption, whereas the floral stems of ‘Violetto di Sicilia clone 4/8’, ‘Nobre’ and ‘Tema 2000’ are suggested for the exploitation as source of natural antioxidants. In addition, the cultivar-dependency of both polyphenol content and antioxidant activity of globe artichoke extracts led to foresee the possible manipulation by specific breeding and selection programmes in order to improve the health-beneficial properties of globe artichoke head. Our findings prove also the influence of harvest time on the polyphenol content and thus suggest giving specific consideration to the other factors (e.g. temperature and photoperiod) that may affect polyphenol biosynthesis and accumulation in globe artichoke plant.

Polyphenolic antioxidant profiles of yellow camellia

Yellow camellia (section Nitidissima Chang) is a subgroup of tea plant with golden yellow flowers. It is a very rare species with potential as antioxidant rich plant as it is closely related to tea. We found, for the first time, that the antioxidant capacity and polyphenolic constituents of six yellow camellia species varied widely. Among them, the dry leaf of Camellia impressinervis had the highest level of oxygen radical absorbance capacity (ORAC, 2270.9μmolTE/g), total phenolic content (TPC, 475.6μmolGAE/g), and proanthocyanidin content (PAC, 66.1μmolCE/g). The ORAC level correlated well with TPC (R2=0.9402), and PAC (R2=0.9954). The compounds responsible for antioxidant activities were further profiled by HPLC and LC–MS analysis. Compared to the commonly consumed tea leaves, yellow camellia leaves contain more diverse phenolic compounds, including ellagitannins, proanthocyanidins, taxifolin deoxyhexose, apigenin derivatives, kaempferol derivative, quercetin derivatives, glucosyl isorhamnetin, (epi)catechin-(epi)afezelechin polymers and platphyllosides. Unlike tea leaves, no caffeine is detected in the yellow camellia leaves. The antioxidant activity of the polyphenolic compounds were further verified by precolumn treatment of the extracts with a stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH).

Antioxidant and aldose reductase inhibition activity of Ligustrum japonicum and Olea europaea L. leaf extracts

AbstractLigustrum japonicum and Olea europaea leaf extracts prepared via domestic techniques were studied for antioxidant and aldose reductase inhibitory activity (ARI) in relation to individual phenol/flavonoid composition (HPLC‐various detection means) and content. On the same extract weight basis L. japonicum leaf extracts, poorer in total polar phenol (TPP) content and in most cases in flavonoids, were less efficient than olive leaf extracts in radical scavenging and in retarding lipid oxidation. On the same TPP content basis, the former were of comparable efficiency in radical scavenging but exhibited lower activity than the latter in bulk oils or liposomes. L. japonicum extracts were characterized by the presence of verbascoside and apigenin derivatives, whereas O. europaea extracts by that of oleuropein. Superiority of L. japonicum infusion versus O. europaea infusion was evidenced using the ARI activity assay either on the same extract weight or on TPP content basis. The former was also superior in comparison to oleuropein, tyrosol, and hydroxytyrosol activity. These findings suggest the presence of other active compounds besides the so far identified phenolics and enhance our view on the importance of Oleaceae plants as sources of bioactive compounds beyond O. europaea.Practical applications: Oleaceae plants are a unique source for the secoiridoid oleuropein or verbascoside that confer well documented biological properties. On continuation of our effort to valorize plants of this family as sources for functional constituents we examined, in parallel, leaf extracts of the less investigated species Ligustrum japonicum versus those of Olea europaea L. The data presented for the extracts obtained via domestic preparations techniques (infusions, decoctions, tinctures) are expected to attract the interest of those involved in herbal teas and dietary supplements sector.

Microbiological quality and biophenol content of hot air‐dried Thassos cv. table olives upon storage

Microbiological quality and biophenol content evolution was studied in minimally processed Thassos cv table olives by hot air dehydration under mild conditions (40°C, 24 h, aw = 0.893) and storage under characteristic packaging conditions (vacuum, 100% N2 and air) at 4 and 20°C over a period of 180 days. No salt was used in the production line or packaging. The undesirable microorganisms (Enterobacteriaceae, Staphylococcus aureus, Bacillus, Clostridium) were undetectable until the end of the storage period. Also, modified atmospheres prevented fungal growth at both temperatures apart from the samples stored in air, in which Penicillium and Aspergillus spp. were identified. At 20°C, a coexistence of mesophilic bacteria and yeasts occurred. At 4°C, yeasts were the predominant microflora. All of the samples analysed were found to be rich sources of the bioactive ingredients, elenolic acid (EA) glycoside and EA. Hydroxytyrosol and derivatives, caffeic acid, luteolin 7-O-glycoside, apigenin derivative and p-coumaric acid derivative assigned as comselogoside were the prevailing phenols in all of the samples. Although the levels of the above compounds decreased upon processing and storage, especially in the samples stored at 4°C, their presence is important for stability because of their high antimicrobial and antioxidant activities. Practical applications: Reducing the amount of salt used in the table olive processing and preservation seems to be an important innovation though this is not a straightforward process, as salt plays an important role in the microbiological quality of the end product. Our study faces such a challenge in the case of minimally processed Thassos cv olives by hot air dehydration under mild conditions (40°C, 24 h, aw = 0.893), which, traditionally, are processed by means of salt. To our knowledge, this is the first report focusing on the evolution of microbiological quality and biophenol content of hot air-dried Thassos olives upon storage under characteristic modified-atmosphere packaging conditions (vacuum and 100% N2). This experimentation provided evidence that this product can be considered as one with a satisfactory microbiological quality and nutritional value with regard to bioactive ingredients and the absence of salt. Assessment of the ‘best before date’ of this product is needed before commercialization.

Approach to the study of C‐glycosyl flavones acylated with aliphatic and aromatic acids from Spergularia rubra by high‐performance liquid chromatography‐photodiode array detection/electrospray ionization multi‐stage mass spectrometry

The use of mass spectrometry (MS) coupled to liquid chromatography (LC) as working tool for the study of the C-glycosyl flavones acylated with aliphatic and aromatic acids has allowed the tentative characterization of these compounds in Spergularia rubra and the establishment of the position of the acylation on the sugar moiety of the C-glycosylation by use of MS data. The combination of retention time (Rt), ultraviolet (UV) and MS(n) data of the compounds revealed their C-glycosyl flavone nature, being luteolin, apigenin and chrysoeriol derivatives. Ten non-acylated flavones were identified, from which six are described for the first time (one 7-O-glycosyl-6,8-diC-glycosyl flavone, four 6,8-diC-glycosyl flavones and one 2"-O-glycosyl-6-C-glycosyl flavone). Twenty-six acylated derivatives were also found for the first time. These compounds are grouped in three classes, namely, C-glycosyl flavones acylated with aliphatic acids, with aromatic acids or with a mixed acylation. The first group is characterized by the presence of one 6,8-diC-(acetyl)glycosyl flavone, four 6,8-diC-(malonyl)glycosyl flavones and two 7-O-glycosyl-6,8-diC-(malonyl)glycosyl flavones, while in the second one twelve 6,8-diC-(acyl)glycosyl flavones and two 7-O-glycosyl-6,8-diC-(acyl)glycosyl flavones are described. The last class contained five 6,8-diC-(malonyl,acyl)glycosyl flavones. No previous work has described the presence of C-glycosyl flavones acylated with aliphatic acids in this genus.

Phenolic acids and flavonoids in leaf and floral stem of cultivated and wild Cynara cardunculus L. genotypes

Ten genotypes, cultivated and wild of Cynara cardunculus L. were evaluated for their content of phenolic acids, flavonoids and their antioxidant activity. The major compounds present in the leaf were luteolin derivatives in globe artichoke and apigenin derivatives in wild and cultivated cardoon. Apart from ‘Cimiciusa di Mazzarino’ (var. scolymus), caffeoylquinic acids represent the main phenolic compounds in the floral stem. In particular, ‘Sylvestris Creta’ (var. sylvestris) and ‘Violetto di Sicilia’ (var. scolymus) show the highest content of caffeoylquinic acid ∼95% of the total measured polyphenols. The antioxidant capacity, in both leaf and floral stem, was qualitatively and quantitatively dependent on the phenolic acid and flavonoid profile. The phenolic acids and flavonoids in normally uneaten parts of wild and cultivated artichoke could be exploited as sources of natural antioxidants.

Phenolic composition and antioxidant activity of culms and sugarcane ( Saccharum officinarum L.) products

The present work reports amounts of flavonoids and phenylpropanoids of culms of three sugarcane varieties and of raw juice, syrup, molasse and VHP sugar. The antioxidant activity of those materials was evaluated by the DPPH and β-carotene/linoleic acid methods. The predominant phenolics in culms were phenylpropanoids (caffeic, chlorogenic and coumaric acids), while flavones (apigenin, tricin and luteolin derivatives) appeared in lower amounts. Differences were noted either among phenolic profiles of sugarcane culms or between culms and sugarcane products. The antioxidant activities of solutions from most samples were similar or higher than a 80 μM Trolox solution.

Phytochemical and biological investigations on Carduus crispus L.

As people are becoming older different forms of dementia are a major public health concern. After a screening of 50 plants used in the Traditional Mongolian Medicine on their acetylcholinesterase inhibitory effect the MeOH extract of Carduus crispus L. (Welted Thistle; Asteraceae) showed a pronounced activity of 60.5% at a conc of 1.000µg/ml. The biological test was performed by the method of Ellman [1, modif.]. Different plant parts (leaves, flowers, stem, roots) were extracted with solvents of different polarities. The highest activity was found in the MeOH mazerate of the leaves (60.9% at 1.000µg/ml) whereas the traditionally used hot water extracts were not as active (32.4% at 1.000µg/ml). The alcoholic extracts showed stronger effects (MeOHcold> MeOHhot> EtOHhot>> H2Ohot). The differences between leaf, flower and stem extracts have not been significant. Separation of MeOH extracts by polarity differences showed a pronounced activity of the n-butanol fraction (stem 59.2%, flower 66.2%, leaf 81.6% at 1.000µg/ml). Fractions with an activity up to 90.9% at 1.000µg/ml were obtained by the use of SPE. The compounds from these fractions isolated by SPE and RP-HPLC could be identified by spectroscopic methods as chlorogenic acid; neochlorogenic acid; p-coumarylquinic acid and apigenin derivatives. These results may substantiate the traditional use of the investigated plant for the improvement of cognition.

Caffeoylquinic Acids and Flavonoids in the Immature Inflorescence of Globe Artichoke, Wild Cardoon, and Cultivated Cardoon

The species Cynara cardunculus is consumed as part of the Mediterranean diet and consists of the globe artichoke [var. scolymus (L.) Fiori], the cultivated cardoon (var. altilis DC.), and the wild cardoon [var. sylvestris (Lamk) Fiori]. The objective of this study was to investigate, in immature inflorescences, the main flavonoids and phenolic acids (caffeoylquinic acids, apigenin, and luteolin derivatives) by HPLC/diode array detection/mass spectrometry. Apigenin derivatives represented the major class in all samples investigated, highest in cardoon forms. Caffeoylquinic acids and luteolin derivatives were observed in var. scolymus only. Data allowed discrimination of globe artichoke from the related species on the basis of the profile of compounds analyzed. Our results suggest the possible use of cultivated and wild cardoon as a source of phenolic acids and flavonoids and indicate that artichoke consumption is an excellent dietary source of apigenin and other flavones.

High-performance liquid chromatography with diode array detection coupled to electrospray time-of-flight and ion-trap tandem mass spectrometry to identify phenolic compounds from a lemon verbena extract

High-performance liquid chromatography with diode array and electrospray ionization mass spectrometric detection was used to carry out the comprehensive characterization of a lemon verbena extract with demonstrated antioxidant and antiinflammatory activity. Two different MS techniques have been coupled to HPLC: on one hand, time-of-flight mass spectrometry, and on the other hand, tandem mass spectrometry on an ion-trap. The use of a small particle size C18 column (1.8 μm) provided a great resolution and made possible the separation of several isomers. The UV–visible spectrophotometry was used to delimit the class of phenolic compound and the accurate mass measurements on time-of-flight spectrometer enabled to identify the compounds present in the extract. Finally, the fragmentation pattern obtained in MS–MS experiments confirmed the proposed structures. This procedure was able to determine many well-known phenolic compounds present in lemon verbena such as verbascoside and its derivatives, diglucuronide derivatives of apigenin and luteolin, and eukovoside. Also gardoside, verbasoside, cistanoside F, theveside, campneoside I, chrysoeriol-7-diglucuronide, forsythoside A and acacetin-7-diglucuronide were found for the first time in lemon verbena.

In VitroRadical Scavenging and Anti-Yeast Activity of Extracts from Leaves ofAloeSpecies Growing in Congo

Extracts obtained from leaves of Aloe barbadensis and A. congolensis, growing in Congo, were analyzed for their in vitro antiradical and anti-yeast activity. Different leaf tissues (tegument and gel) were analyzed separately. Their phenolic fractions showed the presence of chromones and anthrones (aloesin, aloin B, aloin A, and isoaloeresin), flavonoids (apigenin and kaempferol derivatives), and hydroxycinnamic acids. A differential quantitative composition was observed between leaf tegument and gel: in the first, higher concentrations of the four classes of compounds were observed. The extracts from the tegument exhibited higher in vitro antiradical and antimycotic activity than gel extracts. In a few cases, extracts from teguments were active against amphotericin B-insensitive yeasts. Due to the lack of radical scavenging and yeast inhibition observed when aloin was used, it was possible to postulate that the in vitro activities of the teguments could be related to their high concentration of flavonoids and hydroxycinnamic acids.

HPLC/DAD/ESI-MS Analysis of Non-volatile Constituents of Three Brazilian Chemotypes of Lippia alba (Mill.) N. E. Brown

Aqueous preparations and ethanolic extracts of three Brazilian chemotypes of Lippia alba (Mill.) N.E. Brown (Verbenaceae) were investigated for the chemical variability of their non volatile constituents by HPLC/DAD/ESI-MS analysis. The main class of compounds in all the extracts investigated was phenylpropanoids, mainly verbascoside, followed by the flavonoids tricin-7- O-diglucuronide (present in Lippia alba chemotypes 2 and 3), luteolin-7- O-glucuronide (present in L. alba chemotype 1) and mono-and di- O-glucuronic derivatives of apigenin and tricin. Four iridoids, geniposidic acid, theveside, 8- epi-loganin and mussaenoside were also identified.

Concentrations of Foliar Quercetin in Natural Populations of White Birch (Betula pubescens) Increase with Latitude

We investigated latitudinal and regional variations in the composition and concentrations of foliar flavonoids and condensed tannins in wild populations of white birch (Betula pubescens EHRH) in a large climatic transect in Finland. Concentrations of quercetin derivatives were correlated positively with latitude. By contrast, the concentrations of apigenin and naringenin derivatives were correlated negatively with latitude. These compound-specific latitudinal gradients compensated each other, resulting in no changes in the concentration of total flavonoids. Our results thus demonstrate a qualitative, but not quantitative, latitude-associated gradient in the foliar flavonoids in white birch. Due to higher antioxidant capacity of the quercetin derivatives in relation to other flavonoids, the qualitative change can reflect higher adaptation to light in the north than south. An investigation on a regional scale in the northern boreal zone showed that the temperature sum was correlated positively and soil P concentration was correlated negatively with the concentrations of foliar flavonoid, while the concentration of condensed tannins was correlated with slope. The variation in concentrations of flavonoids at large-scale geographical patterns is in line with the conjecture that foliar flavonoids are synthesized for protection against photooxidative stress.