Flavonol tetraglycosides and other constituents from leaves of Styphnolobium japonicum (Leguminosae) and related taxa

Potential antioxidant and cytotoxic impacts of defatted extract rich in flavonoids from Styphnolobium japonicum leaves growing in Egypt

Styphnolobium japonicum leaves are considered a rich source of flavonoids, which are the prospective basis for various therapeutic effects. However, there has been a lack of comprehensive cytotoxic studies conducted on these leaves. Therefore, this ongoing investigation aimed to detect and isolate the flavonoids present in S. japonicum leaves, and assess their antioxidant and anticancer properties. The defatted extract from S. japonicum leaves was analyzed using HPLC, which resulted in the identification of seven phenolics and six flavonoids. Rutin and quercetin were found to be the most abundant. Furthermore, a comprehensive profile of flavonoids was obtained through UPLC/ESI-MS analysis in negative acquisition mode. Fragmentation pathways of the identified flavonoids were elucidated to gain relevant insights into their structural characteristics. Furthermore, genistein 7-O-glucoside, quercetin 3-O-rutinoside, and kaempferol 3-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside were isolated and characterized. The defatted extract rich in flavonoids exhibited significant antioxidant, iron-reducing, free radicals scavenging impacts, and remarkable cytotoxicity against the liver cell line (IC50 337.9μg/ mL) and lung cell line (IC50 55.0 μg/mL). Furthermore, the antioxidant and anticancer capacities of the three isolated flavonoids have been evaluated, and it has been observed that their effects are concentration-dependent. The findings of this research highlight the promising impact of flavonoids in cancer therapy. It is recommended that future scientific investigations prioritize the exploration of the distinct protective and therapeutic characteristics of S. japonicum leaves, which hold significant potential as a valuable natural resource.

Chemical Characterization and Metabolic Profiling of the Compounds in the Chinese Herbal Formula Li Chang Decoction by UPLC-QTOF/MS

Background

Li Chang decoction (LCD), a Chinese medicine formula, is commonly used to treat ulcerative colitis (UC) in clinics.

Purpose

This study aimed to identify the major components in LCD and its prototype and metabolic components in rat biological samples.

Methods

The chemical constituents in LCD were identified by establishing a reliable ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF/MS) method. Afterwards, the rats were orally administered with LCD, and the biological samples (plasma, urine, and feces) were collected for further analyzing the effective compounds in the treatment of UC.

Result

A total of 104 compounds were discriminated in LCD, including 26 flavonoids, 20 organic acids, 20 saponins, 8 amino acids, 5 oligosaccharides, 5 tannins, 3 lignans, 2 alkaloids, and 15 others (nucleosides, glycosides, esters, etc.). About 50 prototype and 94 metabolic components of LCD were identified in biological samples. In total, 29 prototype components and 22 metabolic types were detected in plasma. About 27 prototypes and 96 metabolites were discriminated in urine, and 34 prototypes and 18 metabolites were identified in feces.

Conclusion

The flavonoids, organic acids, and saponins were the major compounds of LCD, and this study promotes the further pharmacokinetic and pharmacological evaluation of LCD.

Production of biologically active hydroxytyrosol rich extract via catalytic conversion of tyrosol

An effective and economical process was established to produce hydroxytyrosol, a naturally occurring orthodiphenolic antioxidant molecule found in olive oil from its monophenolic precursor tyrosol. The approach proposed in the present work presents an environment-friendly method based on wet hydrogen peroxide catalytic oxidation with montmorillonite KSF as an inexpensive and environmentally benign solid acid at room temperature. The influence of the principal operating parameters including concentration of tyrosol, H₂O₂, and catalyst used were studied. The antioxidant activity was realized by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. High antioxidant activity was detected according to the high hydroxytyrosol production (IC₅₀ = 0.7 μg mL⁻¹). The bactericidal and fungicidal properties of hydroxytyrosol rich extract were investigated using the NCCLS broth dilution and EN 1276 standard methods. Positive bactericidal and fungicidal effects of concentrations ranging between 1–0.5 g L⁻¹ and 4–2 g L⁻¹ were obtained.

An effective and economical process was established to produce hydroxytyrosol, a natural antioxidant molecule.

Use of Herbarium Voucher Specimens To Investigate Phytochemical Composition in Poisonous Plant Research

Poisonous plants cause large losses to the livestock industry through death, reduced production efficiency, reproductive dysfunction, and compromised harvesting of rangeland and pasture forages. Research investigating poisonous plants is complex because there are hundreds of genera of toxic plants representing thousands of species. To investigate the effects of poisonous plants on livestock, a clear understanding of the taxonomic identity of the plant and the ability to collect the plant in sufficient quantities for scientific studies is required. Subsequently, the active principles must be defined and investigated in the taxa of interest to better predict risk and make recommendations to reduce losses. Herbaria are collections of preserved plant specimens and are an important resource in poisonous plant research. Voucher specimens have often been used in the identification of the plant for the experimental reproduction of suspected livestock poisoning associated with a spontaneous case. More recently, herbarium specimens have been used to investigate the chemical composition of toxic plants as well as the distribution of different chemotypes over the landscape. The primary purpose of this review is to highlight the chemical analysis of herbarium specimens in poisonous plant research.

Identification and Characterization of a-Glucosidase Inhibition Flavonol Glycosides from Jack Bean (Canavalia ensiformis (L.) DC

Although the intake of jack bean (Canavalia ensiformis (L.) DC.), an underutilized tropical legume, can potentially decrease the risk of several chronic diseases, not much effort has been directed at profiling the polyphenolics contained therein. Hence, this work aimed to identify and quantify the dominant jack bean polyphenolics, which are believed to have antioxidant and other bioactivities. Four major compounds were detected and identified as kaempferol glycosides with three or four glycoside units. Their structures were established based on UV-visible, 1D, 2D NMR, and HR-ESI-MS analyses. Specifically, kaempferol 3-O-α-l-rhamnopyranosyl (1→6)- β-d-glucopyranosyl (1→2)-β-d-galactopyranosyl-7-O-[3-O-o-anisoyl]-α-l-rhamnopyranoside was detected for the first time, while the other three compounds have already been described in plants other than jack bean. This new compound was found to have a higher α-glucosidase inhibition activity compared to acarbose.

Chemical composition, antioxidant activities, in an allergic asthma model, of Olea europaea L. leaf extracts from Collo (Skikda, Algeria)

This study is an attempt to characterize the chemical composition and antioxidant activity of olive leaves variety (namely Bouricha variety) that is very widespread in the East of Algeria. The aqueous extract (AE) of leaves was initially analyzed for its phenolic profile. Using the liquid chromatography coupled to tandem mass spectrometry analysis, it was possible to identify the predominant components in the AE of the leaves. This extract was hydrolyzed with acid and gave hydroxytyrosol (HT). AE and HT were evaluated for their 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power and total antioxidant activity by phosphomolybdenum method. The antioxidant and anti-asthmatic activities of these extracts were examined in a model of experimental asthma in Wistar rats. For measuring the intensity of the airway inflammation, oxidative stress parameters were analyzed in lungs and a histological study of this tissue was performed. The obtained results showed that the sensitization of the ovalbumin (OVA) group induced lung inflammation and severe lipid peroxidation (LPO) revealed by a significant increase in malondialdehyde (MDA) levels and a decrease in the non-enzymatic and enzymatic antioxidant systems. However, the administration of AE and HT extracts significantly improved the antioxidant state in asthma disease and provided evidence for the relation between phenolic compounds and the high antioxidant activity of olive leaves extracts, especially HT more than AE.

Hypolipidemic and cardioprotective effects of Ulva lactuca ethanolic extract in hypercholesterolemic mice

CONTEXT

Hypercholesterolemia has significant cardiac consequences, since it is among the major risk factors of ischemic heart diseases.

OBJECTIVE

The aim was searching the cardioprotective effect of chemical constituents from the sea lettuce Ulva lactuca upon hypercholesterolemic regime in mice.

MATERIAL AND METHODS

Mice were randomly divided into three groups: untreated group, hypercholesterolemic group, and mice receiving 1% cholesterol associated with U. lactuca ethanolic extract.

RESULTS

In vitro study demonstrated that algal extract has antioxidant efficacy attributable to the presence of phenolic compounds. Additionally, the alga alleviated cardiotoxicity, as shown by the improvement of haematological parameters, white cell viability, heart oxidative stress, plasma biochemical parameters and index of atherogenesis. Gene expression of the proinflammatory cytokines TNF-α, IL-1β and IL-6 significantly decreased in the heart of U. lactuca supplemented hypercholesterolemic animals.

CONCLUSION

It was established that the green alga, thanks to its bioactive compounds, effectively counteracts cardiotoxic effects of hypercholesterolemic regime.

A new isoflavane-4-ol derivative from Melilotus officinalis (L.) Pall

A new isoflavane derivative, melilofficinaside together with seven other metabolites including coumarin, uridine, methyl-α-d-fructofuranoside, and flavonoid glucosides were isolated from the aerial parts of Melilotus officinalis (L.) Pall.

Evaluation of phenolic composition and antioxidant activity changes in olive flowers during development using HPLC/DAD and LC-MS/MS

Olive fruit and leaves have been extensively studied for their chemical compositions and biological activities. However, less attention has been given to its flowers. The present research was achieved on Tunisian olive flowers. It aimed at studying the effects of flower development on phenolic compounds and antioxidant activity. The extracts were analyzed using high performance liquid chromatography coupled to diode array detection (HPLC/DAD) and coupled to mass spectrometry (LC-MS/MS). The HPLC/DAD analysis indicated that oleuropein aglycon (from 1.158 to 3.746 g/kg), followed by hydroxytyrosol (from 0.168 to 1.581 g/kg) and oleoside (from 0.143 to 1.325 g/kg) were the predominant phenolics in olive flowers extracts during development stages. Twenty compounds have been identified, revealing the complex profile of olive flowers, composed, in order of abundance, by secoiridoids, phenolic alcohols, lignans, flavonoids and phenolic acids. Total phenolic contents increased from 2.455 to 8.541 g/kg Gallic acid equivalent per kg of fresh flowers during all steps of the flower development. A correlation between antioxidant activity and total phenolic contents was determined.

Flavonoid compounds from the red marine alga Alsidium corallinum protect against potassium bromate-induced nephrotoxicity in adult mice

Potassium bromate (KBrO₃ ), an environmental pollutant, is a well-known human carcinogen and a potent nephrotoxic agent. Currently, natural products have built a well-recognized role in the management of many diseases induced by pollutants. As potent natural sources of bioactive compounds, marine algae have been demonstrated to be rich in novel secondary metabolites with a broad range of biological functions. In this study, adults male mice were orally treated for 15 days with KBrO₃ (0.5 g/L) associated or not with extract of Alsidium corallinum, a red Mediterranean alga. In vitro study demonstrated that algal extract has antioxidant efficacy attributable to the presence of flavonoids and polyphenols. Among these, Liquid chromatography-mass spectrometry analysis showed A. corallinum is rich in kaempferol, apigenin, catechin, and quercetin flavonoids. In vivo study showed that supplementation with the alga significantly prevented KBrO₃ -induced nephrotoxicity as indicated by plasma biomarkers (urea, uric acid, and creatinin levels) and oxidative stress related parameters (malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, vitamin C, hydrogen peroxide, protein oxidation products) in kidney tissue. The corrective effect of A. corallinum on KBrO₃ -induced kidney injury was also supported by molecular and histopathological observations. In conclusion, it was established that the red alga, thanks to its bioactive compounds, effectively counteracts toxic effects of KBrO₃ and could be a useful coadjuvant agent for treatment of this pollutant poisonings. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1475-1486, 2017.

Extraction optimization and in vitro and in vivo anti-postprandial hyperglycemia effects of inhibitor from Phoenix dactylifera L. parthenocarpic fruit

Phoenix dactylifera L. plays an important role in social, economic, and ecological Tunisian sectors. Some date palms produce parthenocarpic fruit named Sish. The aqueous ethanolic extract from P. dactylifera parthenocarpic dates demonstrated a potent inhibition of the enzymes related to type II diabetes. In this work, extraction optimization of amylase inhibitors was carried out using Box-Behnken Design. Bioactivity-guided fractionation of the 70% aqueous ethanol extract was performed to identify the active compounds. The physicochemical results by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed the presence of 13 phenolic compounds. The in vitro study showed that the extract exhibited a more specific inhibitor of α-glucosidase than α-amylase with an IC₅₀ value of 0.6 and 2.5mg/mL, respectively. The in vivo study of this extract effect on the postprandial hyperglycemia activity showed a decrease in plasma glucose levels after 30min stronger than the Acarbose effect. These results confirmed the anti-postprandial hyperglycemia activity of the aqueous ethanolic extract from P. dactylifera parthenocarpic dates, which could lend support for its pharmaceutical use.

Anti-oxidant, anti-inflammatory, analgesic and antipyretic activities of grapevine leaf extract (Vitis vinifera) in mice and identification of its active constituents by LC-MS/MS analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Vitis vinifera is used in traditional medicine for diarrhea, hepatitis and stomachaches. The objective of this study was to investigate the anti-oxidant, anti-inflammatory, analgesic and antipyretic properties of the hydroalcoholic leaf extract of Vitis vinifera (EVV) on experimental models to provide scientific basis for its use.

MATERIALS AND METHODS

The EVV was chemically characterized by LC-MS/MS analyses. The in vitro antioxidant activities of the EVV extract were measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and Ferric reducing antioxidant power assay (FRAP). Analgesic activity using acetic acid induced writhing and formalin test in mice, anti-inflammatory activity using carrageenan induced paw oedema and acetic acid-induced vascular permeability in mice, and antipyretic activity using Brewer's yeast induced pyrexia in rats were evaluated at 100mg/kg, 200mg/kg, and 400mg/kg doses of the extract.

RESULTS

The extract (EVV) was found to contain resveratrol, quercetin, catechin, flavone, flavonols, anthocyanin, gallic acid and epicatechin. EVV produced significant dose-response anti-inflammatory activity against carrageenan-induced paw edema. EVV at dosages of 100, 200 and 400mg/kgbw significantly reduced carrageenan-induced paw edema by 34.48% (P<0.05), 36.20% (P<0.05), and 41.37% (P<0.05) at 5h after carrageenan injection, respectively. Also EVV extract reduces significantly acetic acid-induced vascular permeability in mice dose dependently. EVV (100, 200 and 400mg/kgbw) produced significant dose-response analgesic activity in the formalin test. However, the low percentage inhibition (50%) suggests that it is not a centrally acting analgesic. Extract at dosages of 100, 200 and 400mg/kg bw, p.o. significantly reduced acetic acid-induced writhing by 48.15% (p<0.05), 57.97% (p<0.05), and 68.09% (p<0.05), respectively. The extract also caused marked dose-dependent inhibition of formalin-induced pain in the second phase (p<0.05). Statistical significant reduction in rectal temperatures was observed in standard group at 21 and 23h, and in 200mg/kg and 400mg/kg doses of the extract at 23h (p<0.05) compared with the 19h.

CONCLUSIONS

The results obtained indicated potential analgesic, anti-inflammatory and antipyretic effects of them hydroalcoholic leaf extract of V. vinifera observed at doses tested which support the claim for the traditional use of the plant in the treatment of various inflammatory and pain diseases.

A New Flavonol Triglycoside from Eustoma grandiflorum

A new flavonol triglycoside, kaempferol 3- O-α-L-rhamnopyranosyl (1→6)-(3- O- E- p-coumaroyl)-β-D-galactopyranoside-7- O-α-L-rhamnopyranoside (1: Eustograndifloside A) was isolated from the flower of Eustoma grandiflorum in addition to eight known flavonols (2: kaempferol 3- O-α-L-rhamnopyranosyl (1→6)-(4- O- E- p-coumaroyl)-β-D-galactopyranoside-7- O-α-L-rhamnopyranoside, 3: kaempferol 3- O-β-robinobioside-7- O-α-L-rhamnopyranoside, 4: isorhamne-tin 3- O-α-L-rhamnopyranosyl (1→2) [α-L-rhamnopyranosyl (1→6)]-(4- O- E- p-coumaroyl)-β-D-galactopyranoside-7- O-α-L-rhamnopyranoside, 5: kaempferol 3- O-α-L-rhamnopyranosyl (1→2) [α-L-rhamnopyranosyl (1→6)]-(4- O- E- p-coumaroyl)-β-D-galactopyranoside-7- O-α-L-rhamnopyranoside, 6: kaempferol 3- O-β-robinobioside, 7: quercetin 3- O-β-robinobioside, 8: isorhamnetin 3- O-β-robinobioside, and 9: kaempferol 7- O-α-L-rhamnopyranoside) and two known secoiridoid glycosides (10: swertiamarin and 11: sweroside). The structure elucidation of these compounds was accomplished through analyses of spectroscopic, including 1D and 2D NMR, and ESIMS data.

Local and traditional uses, phytochemistry, and pharmacology of Sophora japonica L.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora japonica (Fabaceae), also known as Huai (Chinese: ), is a medium-sized deciduous tree commonly found in China, Japan, Korea, Vietnam, and other countries. The use of this plant has been recorded in classical medicinal treatises of ancient China, and it is currently recorded in both the Chinese Pharmacopoeia and European Pharmacopoeia. The flower buds and fruits of S. japonica, also known as Flos Sophorae Immaturus and Fructus Sophorae in China, are most commonly used in Asia (especially in China) to treat hemorrhoids, hematochezia, hematuria, hematemesis, hemorrhinia, uterine or intestinal hemorrhage, arteriosclerosis, headache, hypertension, dysentery, dizziness, and pyoderma. To discuss feasible trends for further research on S. japonica, this review highlights the botany, ethnopharmacology, phytochemistry, biological activities, and toxicology of S. japonica based on studies published in the last six decades.

MATERIALS AND METHODS

Information on the S. japonica was collected from major scientific databases (SciFinder, PubMed, Elsevier, SpringerLink, Web of Science, Google Scholar, Medline Plus, China Knowledge Resource Integrated (CNKI), and "Da Yi Yi Xue Sou Suo (http://www.dayi100.com/login.jsp)" for publications between 1957 and 2015 on S. japonica. Information was also obtained from local classic herbal literature, government reports, conference papers, as well as PhD and MSc dissertations.

RESULTS

Approximately 153 chemical compounds, including flavonoids, isoflavonoids, triterpenes, alkaloids, polysaccharides, amino acids, and other compounds, have been isolated from the leaves, branches, flowers, buds, pericarps, and/or fruits of S. japonica. Among these compounds, several flavonoids and isoflavonoids comprise the active constituents of S. japonica, which exhibit a wide range of biological activities in vitro and in vivo such as anti-inflammatory, antibacterial, antiviral, anti-osteoporotic, antioxidant, radical scavenging, antihyperglycemic, antiobesity, antitumor, and hemostatic effects. Furthermore, flavonoids and isoflavonoids can be used as quality control markers for quality identification and evaluation of medicinal materials and their preparations. Information on evaluating the safety of S. japonica is very limited, so further study is required. To enable safer, more effective, and controllable therapeutic preparations, more in-depth information is urgently needed on the quality control, toxicology data, and clinical value of crude extract and active compounds of S. japonica.

CONCLUSIONS

S. japonica has long been used in traditional Chinese medicine (TCM) due to its wide range of biological activities, and is administered orally. Phytochemical and pharmacological studies of S. japonica have increased in the past few years, and the extract and active components of this plant can be used to develop new drugs based on their traditional application as well as their biological activities. Therefore, this review on the ethnopharmacology, phytochemistry, biological activities, and toxicity of S. japonica offers promising data for further studies as well as the commercial exploitation of this traditional medicine.

Phenolic Profiles, Phytchemicals and Mineral Content of Decoction and Infusion of Opuntia ficus-indica Flowers

Opuntia flowers are a natural source of biologically active compounds and they have been used as medicinal plant for a long time. Despite the various uses reported for the decoction and infusion of these flowers, their characterization has been discarded. In this study, the decoction and infusion prepared from Opuntia ficus-indica were analyzed with respect to their content in minerals and phytochemicals in order to evaluate its nutritional characteristics. The obtained data proved that these preparations are a rich source of minerals mainly K and Ca. Moreover, the phytochemical analysis revealed that they have important polyphenols, flavonoids and tannins contents with the infusion that presented the highest polyphenol levels. LC-MS analyses of decoction and infusion allowed the characterization of 20 phenolic compounds. It is mainly identified by the presence of flavonols glycosides.

New Flavonol Glycoside from the Leaves of Ventilago africana

A new flavonol diglycoside, rhamnocitrin-3- O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside, was isolated from the leaves of Ventilago Africana. in addition to 11 known flavonoids. Their structures were determined by spectroscopic methods including 1D- and 2D-NMR, and HR-ESI-MS analysis. The isolated compounds were evaluated for their antioxidant activity by using DPPH radical-scavenging assay. Compounds 4, 7–9 have discrete to good antioxidant potential with EC50 values ranging from 20.9 to 40.4 μM. compared with ascorbic acid (EC50 60 μM) used as positive control.

Phenolic profile characterization of Chemlali olive stones by liquid chromatography-ion trap mass spectrometry

Aqueous methanol extracts of Chemlali olive stones were analyzed by reverse phase high-performance liquid chromatography (HPLC) with diode array detection and mass spectrometry [LC-MS/MS]. Oleoside, oleoside 11-methyl ester, nuezhenide, oleoside 11-methyloleoside, nuezhenide 11-methyloleoside, oleuropein, and glycosides of tryosol and hydroxytyrosol glycosides were identified in stones of Chemali olives. The antioxidant activity observed for the extract of the olive stones (IC50 = 13.84 μg/mL, TEAC = 0.436 mM) may be due to the high content of phenolic compounds, of which the main compounds are nuezhenide (325.78 mg/100g), methoxy derivative of nuezhenide (132.46 mg/100g), and nuezhenide-11-methyloleoside (82.91 mg/100g). These results suggest the use of olive stones as sources of natural antioxidants.

Triterpenoid glycosides from the leaves of Meliosma henryi

Seven triterpenoid glycosides, named meliosmosides A-G, were isolated from the leaves of Meliosma henryi Diels (Sabiaceae). Their structures were elucidated by different spectroscopic methods including 1D and 2D NMR experiments as well as HRESIMS analysis. Isolated compounds were evaluated for their cytotoxic activity against KB cell line.

Characterization of complete genome and small RNA profile of pagoda yellow mosaic associated virus, a novel badnavirus in China

A new badnavirus was discovered from pagoda trees showing yellow mosaic symptoms on the leaves by high throughput sequencing of small RNAs. The complete genome of this virus was determined to comprise 7424 nucleotides, and the virus shared 40.4-45.1% identity with that of other badnaviruses. The genome encodes five open reading frames (ORFs) on the plus strand, which includes three conserved badnaviral ORFs. These results suggest that this virus is a new member of the genus Badnavirus in the family Caulimoviridae. The virus is tentatively named pagoda yellow mosaic associated virus (PYMAV). Phylogenetic analysis suggested that this virus together with gooseberry vein banding virus (GVBV) and grapevine vein-clearing virus (GVCV) forms a separate group that is distinct two other well characterized badnaviral groups. Additionally, the viral derived small RNA (vsRNA) profile of PYMAV was analyzed and compared with that of viruses within the same family. Results showed that the most abundant PYMAV vsRNAs were 21-nt, whereas other viruses in the same family have a predominance of 22- or 24-nt vsRNA. The percentage of sense PYMAV vsRNA was almost equal to that of antisense vsRNA, whereas vsRNAs of other viruses in the family display preferences toward the sense strand of their genome. Furthermore, PYMAV vsRNAs were symmetrically distributed along the genome with no obvious vsRNA generating hotspots.

Variation in chemical composition and allelopathic potential of mixoploid Trigonella foenum-graecum L. with developmental stages

This study was conducted to evaluate the influence of developmental stages (vegetative, flowering and fruiting) of mixoploid fenugreek aerial parts on their chemical composition and allelopathic potential, assessed on lettuce germination and seedling growth. Aqueous and organic extracts significantly delayed germination, reduced its rate and affected seedling growth. Ethyl acetate and methanol extracts of aerial parts harvested at vegetative stage were the most toxic for lettuce germination and seedling growth, respectively. LC-MS/MS analysis of T. foenum-graecum aerial parts methanolic extract showed nine different flavonol glycosides (quercetin and kaempferol glucosides). Chemical composition of aerial parts differed with the developmental stage; indeed, at the vegetative and fruiting stages, analysis revealed the presence of 9 compounds as compared to only 6 compounds at the flowering stage. Thus, it is necessary to follow the qualitative changes of allelochemicals production at different developmental stages to identify the most productive one.

Flavonoid glycosides from the stem bark of Margaritaria discoidea demonstrate antibacterial and free radical scavenging activities

One new flavonoid glycoside, along with three known flavonoid glycosides were isolated from the stem bark of Margaritaria discoidea, which is traditionally used in the management of wounds and skin infections in Ghana. The new flavonoid glycoside was elucidated as hydroxygenkwanin-8-C-[α-rhamnopyranosyl-(1 → 6)]-β-glucopyranoside (1) on the basis of spectroscopic analysis. The isolated compounds demonstrated free-radical scavenging as well as some level of antibacterial activities. Microorganisms including Staphylococcus aureus are implicated in inhibiting or delaying wound healing. Therefore, any agent capable of reducing or eliminating the microbial load present in a wound as well as decreasing the levels of reactive oxygen species may facilitate the healing process. These findings therefore provide some support to the ethnopharmacological usage of the plant in the management of wounds.

Two new flavonol glycosides from the Tibetan medicinal plant Aconitum tanguticum

Two new flavonol glycosides characterized as quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)-α-l-(4-O-trans-p-coumaroylrhamnopyranosyl)-(1 → 6)]-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (1) and kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)-α-l-(4-O-trans-p-coumaroyl rhamnopyranosyl)-(1 → 6)]-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (2), together with two known flavonol glycosides quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)- [α-l-rhamnopyranosyl-(1 → 6)]-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (3) and kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (4), were isolated from the whole plant of Aconitum tanguticum (Maxim.) Stapf. The structures of the new compounds were elucidated by spectroscopic methods, and the total (1)H and (13)C NMR chemical shifts were assigned.

Enhanced profiling of flavonol glycosides in the fruits of sea buckthorn (Hippophae rhamnoides)

Use of enhanced LC-MS/MS methods to identify common glycosyl groups of flavonoid glycosides enabled better characterization of the flavonoids in fruits of sea buckthorn (Hippophae rhamnoides). The saccharide moieties of 48 flavonol O-glycosides detected in a methanol extract were identified by these methods. Several of the flavonol glycosides were acylated, two of which were isolated and found to be new compounds. Their structures were determined using spectroscopic and chemical methods as isorhamnetin 3-O-(6-O-E-sinapoyl-β-D-glucopyranosyl)-(1→2)-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (24) and isorhamnetin 3-O-(6-O-E-feruloyl-β-D-glucopyranosyl)-(1→2)-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (30). Analysis of the acylated glycosyl groups of 24 and 30 by serial mass spectrometry provided evidence to suggest the acylation position of 11 other minor flavonol glycosides acylated with hydroxycinnamic or hydroxybenzoic acids. The nitric oxide scavenging activities of 24 and 30 were compared with those of other flavonoids and with ascorbic acid and the potassium salt of 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3-oxide (carboxy-PTIO).

Flavone C-glycosides from the flowers of Trollius chinensis and their anti-complementary activity

Phytochemical investigation of ethanol extract from the flowers of Trollius chinensis Bunge resulted in the isolation of two new flavone C-glycosides (1-2), along with 10 known compounds (3-12). The structures of the new compounds were established as 6‴-(3-hydroxy-3-methylglutaroyl)-2″-O-β-d-galactopyranosyl orientin (1) and 6‴-(3-hydroxy-3-methylglutaroyl)-2″-O-β-d-galactopyranosyl vitexin (2) on the basis of various spectroscopic analysis (including different 1D and 2D NMR spectroscopies, high-resolution electrospray ionization mass spectrometry) and chemical evidences. Bioassay showed that eight flavonoids inhibited complement activation on the classic pathway in vitro, with their IC50 values ranging from 0.88 to 4.02 mM, which may contribute to the applications of the herb in treatment of acute respiratory distress syndrome, etc.

Antioxidant capacity and HPLC-DAD-MS profiling of Chilean peumo (Cryptocarya alba) fruits and comparison with German peumo (Crataegus monogyna) from southern Chile

Liquid chromatography (LC) coupled with UV detection and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the generation of chemical fingerprints and the identification of phenolic compounds in peumo fruits and aerial parts from southern Chile. Thirty three compounds (19 of these detected in C. alba and 23 in C. monogyna) were identified, mainly flavonoid glycosides, phenolic acids, anthocyanins and flavonoid aglycons. Total phenolic content and total flavonoid content was measured for both species, and were higher in the extracts from C. monogyna fruits and aerial parts than extracts from C. alba. The fruits of Cryptocarya alba (Chilean peumo) presented high antioxidant capacity (9.12 ± 0.01 mg/mL in the DPPH assay), but was three times lower to that of Crataegus monogyna (German peumo) (3.61 ± 0.01 mg/mL in the DPPH assay).

The Passiflora tripartita (Banana Passion) fruit: a source of bioactive flavonoid C-glycosides isolated by HSCCC and characterized by HPLC–DAD–ESI/MS/MS

The banana passion fruit (Passiflora tripartita Breiter, Passifloraceae) known as “tumbo” is very appreciated in tropical and subtropical countries of South America. Methanolic extracts from peel and the fruit juice of P. tripartita growing in Chile were analyzed for antioxidant capacity as well as for flavonoid and phenolic content. A chromatographic method was developed for the rapid identification of the main phenolics in the samples by HPLC-DAD and HPLC-MS. The fast fingerprint analysis allowed the detection of eighteen flavonoid C-glycosides and four flavonoid O-glycoside derivatives which were characterized by UV spectra and ESI-MS-MS analysis. Several of the C-glycosides detected are structurally related to the orientin derivative 4′-methoxy-luteolin-8-C-(6″acetyl)-β-D-glucopyranoside (31), fully elucidated by spectroscopic methods. The antioxidant derivative 31 along with schaftoside, vicenin II, orientin and vitexin were isolated from the fruit extract by high-speed countercurrent chromatography (HSCCC). A suitable method for the preparative isolation of flavonol C-glycosides from “tumbo” extracts by HSCCC is reported. The pulp of the fruits showed good antioxidant capacity (12.89 ± 0.02 μg/mL in the DPPH assay). The peel presented the highest content of flavonoids (56.03 ± 4.34 mg quercetin/100 g dry weight) which is related to the highest antioxidant power (10.41 ± 0.01 μg/mL in the DPPH assay).

Two new flavonol glycosides from the leaves of Elaeagnus pungens

The leaves of Elaeagnus pungens were extracted with 70% ethanol and successively purified by column chromatography. Seven constituents were obtained and characterized, all of which belong to the class of flavonol glycosides. Their structures were elucidated on the basis of spectroscopic methods including 1D/2D NMR and MS analysis techniques. The seven flavonol glycosides were determined as kaempferol 3-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 6)-[α-l-rhamnopyranosyl(1 → 2)]-β-d-galactopyranoside (1), isorhamnetin 3-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside (2), together with five known compounds, respectively. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliu-m bromide assay in vitro showed that the isolated flavonol glycosides showed no proliferation activity in the asthma airway smooth muscle cells, comparing with solvent as the control group.

Comparative study on hypocholesterolemic and antioxidant activities of various extracts of fenugreek seeds

The hypocholesterolemic and antioxidant activities of various extracts (water, methanol, ethyl acetate, hexane, dichloro-methane) of fenugreek seeds were investigated in cholesterol-fed rats. Only the ethyl acetate extract reduced total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) compared with those of rats fed a cholesterol-rich diet (HCD). Furthermore, the content of thiobarbituric acid-reactive substances (TBARS), and catalase and superoxide dismutase (SOD) in liver, heart and kidney decreased significantly after oral administration of the ethyl acetate extract, compared with those of HCD-fed rats. The phenolic and flavonoïd contents were highest in the methanol and the ethyl acetate extracts. These results showed that the ethyl acetate extract of the fenugreek seeds had a significant hypocholesterolemic effect and antioxidant activity in cholesterol-fed rats, whether this is partly due to the presence of flavonoïds in the extract needs further study.

Two new cembranoids from the leaves of Croton longissimus Airy Shaw

Two new cembrane-type diterpenoids (1 and 2) along with five known compounds (3-7) were isolated from leaves of Croton longissimus collected in Thailand. Their structures were elucidated from spectroscopic evidence and compound 4 was found by HPLC analysis to be identical to oblongionoside B-a compound isolated from Croton oblongifolius-including the absolute configuration at the C-9 position.

Distinct chemotypes of Tephrosia vogelii and implications for their use in pest control and soil enrichment

Tephrosia vogelii Hook. f. (Leguminosae) is being promoted as a pest control and soil enrichment agent for poorly-resourced small-scale farmers in southern and eastern Africa. This study examined plants being cultivated by farmers and found two chemotypes. Chemotype 1 (C1) contained rotenoids, including deguelin, rotenone, sarcolobine, tephrosin and α-toxicarol, required for pest control efficacy. Rotenoids were absent from chemotype 2 (C2), which was characterised by prenylated flavanones, including the previously unrecorded examples (2S)-5,7-dimethoxy-8-(3-hydroxy-3-methylbut-1Z-enyl)flavanone, (2S)-5,7-dimethoxy-8-(3-methylbut-1,3-dienyl)flavanone, (2S)-4'-hydroxy-5-methoxy-6″,6″-dimethylpyrano[2″,3″:7,8]flavanone, (2S)-5-methoxy-6″,6″-dimethyl-4″,5″-dihydrocyclopropa[4″,5″]furano[2″,3″:7,8]flavanone, (2S)-7-hydroxy-5-methoxy-8-prenylflavanone, and (2R,3R)-3-hydroxy-5-methoxy-6″,6″-dimethylpyrano[2″,3″:7,8]flavanone. The known compounds (2S)-5-methoxy-6″,6″-dimethylpyrano[2″,3″:7,8]flavanone (obovatin 5-methyl ether) and 5,7-dimethoxy-8-(3-hydroxy-3-methylbut-1Z-enyl)flavone (Z-tephrostachin) were also found in C2. This chemotype, although designated Tephrosia candida DC. in collections originating from the World Agroforestry Centre (ICRAF), was confirmed to be T. vogelii on the basis of morphological comparison with verified herbarium specimens and DNA sequence analysis. Sampling from 13 locations in Malawi where farmers cultivate Tephrosia species for insecticidal use indicated that almost 1 in 4 plants were T. vogelii C2, and so were unsuitable for this application. Leaf material sourced from a herbarium specimen of T. candida contained most of the flavanones found in T. vogelii C2, but no rotenoids. However, the profile of flavonol glycosides was different to that of T. vogelii C1 and C2, with 6-hydroxy-kaempferol 6-methyl ether as the predominant aglycone rather than kaempferol and quercetin. The structures of four unrecorded flavonol glycosides present in T. candida were determined using cryoprobe NMR spectroscopy and MS as the 3-O-α-rhamnopyranosyl(1→6)-β-galactopyranoside-7-O-α-rhamnopyranoside, 3-O-α-rhamnopyranosyl(1→2)[α-rhamnopyranosyl(1→6)]-β-galactopyranoside, 3-O-α-rhamnopyranosyl(1→2)[α-rhamnopyranosyl(1→6)]-β-galactopyranoside-7-O-α-rhamnopyranoside, and 3-O-α-rhamnopyranosyl(1→2)[(3-O-E-feruloyl)-α-rhamnopyranosyl(1→6)]-β-galactopyranosides of 6-hydroxykaempferol 6-methyl ether. Tentative structures for a further 37 flavonol glycosides of T. candida were assigned by LC-MS/MS. The correct chemotype of T. vogelii (i.e. C1) needs to be promoted for use by farmers in pest control applications.

Spectaflavoside A, a new potent iron chelating dimeric flavonol glycoside from the rhizomes of Zingiber spectabile Griff

The rhizomes of Zingiber spectabile yielded a new dimeric flavonol glycoside for which the name kaempferol-3-O-(4″-O-acetyl)-α-L-rhamnopyranoside-(I-6,II-8)-kaempferol-3-O-(4″-O-acetyl)-α-L-rhamnopyranoside; spectaflavoside A (1) was proposed, along with kaempferol and its four acetylrhamnosides (2-6), demethoxycurcumin (7) and curcumin (8). The structure of spectaflavoside A was elucidated by spectroscopic methods including, 1D and 2D NMR techniques. This is the first report on the occurrence of a dimeric flavonol glycoside in the Zingiberaceae and the second in nature. Spectaflavoside A was found to be a potent iron chelating agent.

Investigations into the phenolic constituents of dog's mercury (Mercurialis perennis L.) by LC-MS/MS and GC-MS analyses

INTRODUCTION

Dog's mercury (Mercurialis perennis L.) is a traditional European medicinal plant considered as a rich source of bioactive natural products. Yet phytochemical data of the plant are scant.

OBJECTIVE

This study aimed to identify the hydrophilic phenolic constituents from M. perennis by aqueous and hydroalcoholic extraction.

METHODOLOGY

Extracts of herbal parts were investigated in-depth by HPLC(DAD)-MS/MS and GC/MS analyses. In addition, a novel compound was isolated and fully characterised by 1- and 2D-NMR experiments.

RESULTS

Several conjugates of caffeic, p-coumaric and ferulic acids together with glucaric or 2-hydroxyglutaric acids (depsides) were detected in the aqueous extracts from aerial plant parts by use of LC-MS/MS techniques as well UV-spectral data. By implementation of preparative chromatography on polyamide pretreated with formic acid followed by vacuum liquid chromatography on reversed-phase C(18) -silica, one of the predominant depsides was isolated as a pure compound. The NMR spectra ((1) H and (13) C NMR) together with 2D-hetereonuclear multiple bond correlation NMR experiments (gHMBC and gHSQC) and chiral GC investigation, allowed identification of this compound as (-)-(E)-caffeoyl-2-(R)-oxoglutarate. This structure was additionally supported by GC/MS data after silylation and methylation reactions. The hydroalcoholic extract from aerial parts was separated by solvent partition between ethyl acetate and n-butanol. The latter fraction (n-butanol) yielded a mixture of mono- and oligo-glycosides of kaempferol and quercetin, all of them being assigned by LC-MS/MS.

CONCLUSIONS

The present investigation constitutes the first comprehensive report on the hydrophilic constituents of the rarely studied plant Mercurialis and thus completes the phytochemical knowledge on M. perennis.

Identification of common glycosyl groups of flavonoid O-glycosides by serial mass spectrometry of sodiated species

Flavonoid O-glycosides are a ubiquitous and important group of plant natural products in which a wide variety of sugars are O-linked to an aglycone. Determining the identity of the sugars, and the manner in which they are linked, by mass spectrometry alone is challenging. To improve the identification of common O-linked di- and trisaccharides when analysing mixtures of flavonoid O-glycosides by liquid chromatography/mass spectrometry (LC/MS), the fragmentation of electrosprayed sodium adducts in an ion trap mass spectrometer was investigated. The sodium adducts [M + Na](+) of kaempferol 3-O-glycosides generated sodiated glycosyl groups by the neutral loss of kaempferol. The product ion spectra of these sodiated glycosyl groups differed between four isomeric kaempferol 3-O-rhamnosylhexosides and four isomeric kaempferol 3-O-glucosylhexosides in which the primary hexose was either glucose or galactose and bore the terminal glucose or rhamnose at either C-2 or C-6. Fragmentation of sodiated glycosyl groups from linear O-triglucosides and branched O-glucosyl-(1 → 2)-[rhamnosyl-(1 → 6)]-hexosides produced sodiated disaccharide residues, and the product ion spectra of these ions assisted the identification of the complete sugar. The product ion spectra of the sodiated glycosyl groups were consistent among flavonoid O-glycosides differing in the position at which the sugar was O-linked to the aglycone, and the nature of the aglycone. The abundance of sodiated species was enhanced by application of a pre-trap collision voltage, without the need to dope with salt, allowing automated LC/MS methods to be used to identify the glycosyl groups of common flavonoid O-glycosides, such as rutinosides, robinobiosides, neohesperidosides, gentiobiosides and sophorosides.

Acylated flavonol tri- and tetraglycosides in the flavonoid metabolome of Cladrastis kentukea (Leguminosae)

The foliar metabolome of Cladrastis kentukea (Leguminosae) contains a complex mixture of flavonoids including acylated derivatives of the 3-O-rhamnosyl(1→2)[rhamnosyl(1→6)]-galactosides of kaempferol and quercetin and their 7-O-rhamnosides, together with an array of non-acylated kaempferol and quercetin di-, tri- and tetraglycosides. Thirteen of the acylated flavonoids, 12 of which had not been reported previously, were characterised by spectroscopic and chemical methods. Eight of these were the four isomers of kaempferol 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E/Z-p-coumaroyl-β-d-galactopyranoside) and their 7-O-α-l-rhamnopyranosides, and three were isomers of quercetin 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E/Z-p-coumaroyl-β-d-galactopyranoside) - the remaining 4Z isomer was identified by LC-UV-MS analysis of a crude extract. The final two acylated flavonoids characterised by NMR were the 3E and 4E isomers of kaempferol 3-O-α-l-rhamnopyranosyl(1→2)[α-l-rhamnopyranosyl(1→6)]-(3/4-O-E-feruloyl-β-d-galactopyranoside)-7-O-α-l-rhamnopyranoside while the 3Z and 4Z isomers were again detected by LC-UV-MS. Using the observed fragmentation behaviour of the isolated compounds following a variety of MS experiments, a further 18 acylated flavonoids were given tentative structures by LC-MS analysis of a crude extract. Acylated flavonoids were absent from the flowers of C. kentukea, which contained an array of non-acylated kaempferol and quercetin glycosides. Immature fruits contained kaempferol 3-O-α-rhamnopyranosyl(1→2)[α-rhamnopyranosyl(1→6)]-β-galactopyranoside and its 7-O-α-rhamnopyranoside as the major flavonoids with acylated flavonoids, different from those in the leaves, only present as minor constituents. The presence of acylated flavonoids distinguishes the foliar flavonoid metabolome of C. kentukea from that of a closely related legume, Styphnolobium japonicum, which contains a similar range of non-acylated flavonoids.