New Sulphated Flavonoids from Wissadula periplocifolia (L.) C. Presl (Malvaceae)

In Vitro Antioxidant and In Vivo Hepatoprotective Properties of Wissadula periplocifolia Extract

Wissadula periplocifolia (L.) Thwaites is a traditional medicinal plant belonging to the family Malvaceae, used in folk medicine for inflamed snake bites and bee stings. The current study was designed to investigate the in vitro antioxidant and in vivo anti-inflammatory and hepatoprotective activities of 80% ethanol extract of W. periplocifolia and its different fractions. The crude ethanolic extract (CEE) was then serially fractionated with petroleum ether fraction (PEF), chloroform fraction (CHF), and aqueous fraction (AQF). The antioxidant activity was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, anti-inflammatory activity was determined in the xylene-induced ear edema model, and hepatoprotective activity was measured in the paracetamol-induced hepatic injury model. PEF showed a significant scavenging effect with an IC50 value of 33.5 μg/mL, followed by CEE (IC50 = 42.2 μg/mL), CHF (IC50 = 77 μg/mL), and AQF (IC50 = 80 μg/mL), compared to standard butylated hydroxytoluene (IC50 = 14.8 μg/mL). Both doses of CEE (250 and 500 mg/kg) could reduce ear edema by 41.3 and 50%, respectively, compared to standard diclofenac sodium (76.09%). Moreover, CEE significantly reduces the elevated liver enzymes (ALT, AST, and ALP), compared to control. Nevertheless, it elevated blood protein and reduced the blood bilirubin level (p < 0.01), compared to control. Histopathological studies also indicated significant protection of the liver from paracetamol-induced liver damage. In conclusion, W. periplocifolia could be a good source of antioxidant and hepatoprotective phytochemicals; meanwhile, toxicological and pharmacokinetic studies are recommended.

α-Glucosidase inhibition of sesquiterpenoids from the heartwood of Mansonia gagei

Nine undescribed sesquiterpenoids, along with ten known compounds, were isolated from the ethyl acetate extract of Mansonia gagei heartwood. Their structures were determined by spectroscopic data analysis (FTIR, 1D, 2D NMR, and HRESIMS), and their absolute configurations were established by ECD calculation. The isolated compounds were evaluated for their inhibitory effect against α-glucosidase from yeast. The results showed that mansonone U, mansonialactam, heliclactone and mansonone S exhibited exceptionally potent activities when compared to the positive control, acarbose, with IC₅₀ values of 12.38 ± 0.71, 0.20 ± 0.05, 13.12 ± 2.85, and 12.05 ± 1.91 μM, respectively. Among them, mansonialactam possessed the most potent inhibitory activity against yeast α-glucosidase, and it showed an uncompetitive inhibition mode.

New Insights of Biological Functions of Natural Polyphenols in Inflammatory Intestinal Diseases

The intestine is critically crucial for nutrient absorption and host defense against exogenous stimuli. Inflammation-related intestinal diseases, including enteritis, inflammatory bowel disease (IBD), and colorectal cancer (CRC), are heavy burdens for human beings due to their high incidence and devastating clinical symptoms. Current studies have confirmed that inflammatory responses, along with oxidative stress and dysbiosis as critical pathogenesis, are involved in most intestinal diseases. Polyphenols are secondary metabolites derived from plants, which possess convincible anti-oxidative and anti-inflammatory properties, as well as regulation of intestinal microbiome, indicating the potential applications in enterocolitis and CRC. Actually, accumulating studies based on the biological functions of polyphenols have been performed to investigate the functional roles and underlying mechanisms over the last few decades. Based on the mounting evidence of literature, the objective of this review is to outline the current research progress regarding the category, biological functions, and metabolism of polyphenols within the intestine, as well as applications for the prevention and treatment of intestinal diseases, which might provide ever-expanding new insights for the utilization of natural polyphenols.

New Sesquiterpene Glycosides from the Flowers of Aster koraiensis and Their Inhibition Activities on EGF- and TPA-Induced Cell Transformation

In total, four new eudesmane-type sesquiterpene glycosides, askoseosides A-D (1-4), and 18 known compounds (5-22) were isolated from the flowers of Aster koraiensis via chromatographic techniques. Chemical structures of the isolated compounds were identified by spectroscopic/spectrometric methods, including NMR and HRESIMS, and the absolute configuration of the new compounds (1 and 2) was performed by electronic circular dichroism (ECD) studies. Further, the anticancer activities of the isolated compounds (1-22) were evaluated using the epidermal growth factor (EGF)-induced as well as the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation assay. Among the 22 compounds, compounds 4, 9, 11, 13-15, 17, 18, and 22 significantly inhibited both EGF- and TPA-induced colony growth. In particular, askoseoside D (4, EGF: 57.8%; TPA: 67.1%), apigenin (9, EGF: 88.6%; TPA: 80.2%), apigenin-7-O-β-d-glucuronopyranoside (14, EGF: 79.2%; TPA: 70.7%), and 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol (22, EGF: 60.0%; TPA: 72.1%) showed higher potent activities.

Autofluorescence-Based Investigation of Spatial Distribution of Phenolic Compounds in Soybeans Using Confocal Laser Microscopy and a High-Resolution Mass Spectrometric Approach

In this research, we present a detailed comparative analysis of the bioactive substances of soybean varieties k-11538 (Russia), k-11559 (Russia), k-569 (China), k-5367 (China), k-5373 (China), k-5586 (Sweden), and Primorskaya-86 (Russia) using an LSM 800 confocal laser microscope and an amaZon ion trap SL mass spectrometer. Laser microscopy made it possible to clarify in detail the spatial arrangement of the polyphenolic content of soybeans. Our results revealed that the phenolics of soybean are spatially located mainly in the seed coat and the outer layer of the cotyledon. High-performance liquid chromatography (HPLC) was used in combination with an amaZon SL BRUKER DALTONIKS ion trap (tandem mass spectrometry) to identify target analytes in soybean extracts. The results of initial studies revealed the presence of 63 compounds, and 45 of the target analytes were identified as polyphenolic compounds.

Comparative Study of the Pharmacological Properties of Luteolin and Its 7,3′-Disulfate

The global spread of the metabolic syndrome, oncological and viral diseases forces researchers to pay increased attention to the secondary metabolites of marine hydrobionts, which often have a high therapeutic potential in the treatment of these pathologies and are effective components of functional food. The flavone luteolin (LT), as one of the most widely distributed and studied plant metabolites, is distinguished by a diverse spectrum of biological activity and a pleiotropic nature of the mechanism of action at the molecular, cellular and organismal levels. However, there is still practically no information on the spectrum of biological activity of its sulfated derivatives, which are widely represented in seagrasses of the genus Zostera. In the present work, a comparative study of the pharmacological properties of LT and its 7,3′-disulfate was carried out with a brief analysis of the special role of sulfation in the pharmacological activity of flavonoids.

Phytochemical Constituents of Aquilaria malaccensis Leaf Extract and Their Anti-Inflammatory Activity against LPS/IFN-γ-Stimulated RAW 264.7 Cell Line

This study aims to identify the major phytochemical constituents in Aquilaria malaccensis (Thymelaeaceae) ethanolic leaf extract (ALEX-M) and elucidate their ability to suppress nitric oxide (NO) production from a murine macrophage-like cell line (RAW 264.7) stimulated by lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Dichloromethane (DCM) and ethyl acetate (EtOAc) fractions of ALEX-M were subjected to column chromatography. Eight known compounds were isolated for the first time from this species. Compounds were identified using spectroscopic techniques (IR, UV, HRESIMS, and 1D and 2D NMR). Anti-inflammatory activity of both extract and isolated compounds were investigated in vitro. The fractions offered the isolation of epifriedelanol (1), 5-hydroxy-7,4'-dimethoxyflavone (2), luteolin-7,3',4'-trimethyl ether (3), luteolin-7,4'-dimethyl ether (4), acacetin (5), aquilarinenside E (6), iriflophenone-2-O-α-l-rhamnopyranoside (7), and iriflophenone-3-C-β-glucoside (8). The findings suggest the pharmacological potential of the crude extract (ALEX-M) and its isolates as natural anti-inflammatory agents, capable of suppressing NO production in RAW 264.7 cells stimulated by LPS/IFN-γ.

Antiplasmodial Activity of Vachellia xanthophloea (Benth.) P.J.H. Hurter (African Fever Tree) and Its Constituents

Vachellia xanthophloea is used in Zulu traditional medicine as an antimalarial remedy. A moderate antiplasmodial activity was previously reported for extracts of the plant against D10 Plasmodium falciparum. This study aimed to identify the phytochemicals responsible for the antiplasmodial activity of the leaf extract. The compounds were isolated by chromatography and their structures were determined using spectroscopic and spectrometric methods. The antiplasmodial activity was evaluated using a parasite lactate dehydrogenase assay and cytotoxicity was determined using a resazurin assay. The ethyl acetate fraction inhibited P. falciparum with IC50 = 10.6 µg/mL and showed minimal cytotoxicity (98% cell viability at 33 µg/mL). The chromatographic purification of this fraction afforded sixteen compounds, including two new flavonoids. A 1:1 mixture of phytol and lupeol was also isolated from the hexane fraction. All the compounds were reported from V. xanthophloea for the first time. Among the isolated metabolites, methyl gallate displayed the best activity against P. falciparum (IC50 = 1.2 µg/mL), with a 68% viability of HeLa cells at 10 µg/mL. Therefore, methyl gallate was responsible for the antiplasmodial activity of the V. xanthophloea leaf extract and its presence in the leaf extract might account for the folkloric use of the plant as an antimalarial remedy.

Spatial Distribution of Polyphenolic Compounds in Corn Grains (Zea mays L. var. Pioneer) Studied by Laser Confocal Microscopy and High-Resolution Mass Spectrometry

Desirable changes in the biochemical composition of food plants is a key outcome of breeding strategies. The subsequent localization of nutritional phytochemicals in plant tissues gives important information regarding the extent of their synthesis across a tissue. We performed a detailed metabolomic analysis of phytochemical substances of grains from Zea mays L. (var. Pioneer) by tandem mass spectrometry and localization by confocal microscopy. We found that anthocyanins are located mainly in the aleurone layer of the grain. High-performance liquid chromatography in combination with ion trap tandem mass spectrometry revealed the presence of 56 compounds, including 30 polyphenols. This method allows for effective and rapid analysis of anthocyanins by plotting their distribution in seeds and grains of different plants. This approach will permit a more efficient screening of phenotypic varieties during food plant breeding.

Dracocephalum palmatum S. and Dracocephalum ruyschiana L. Originating from Yakutia: A High-Resolution Mass Spectrometric Approach for the Comprehensive Characterization of Phenolic Compounds

Dracocephalum palmatum S. and Dracocephalum ruyschiana L. contain a large number of target analytes, which are biologically active compounds. High performance liquid chromatography (HPLC) in combination with an ion trap (tandem mass spectrometry) was used to identify target analytes in extracts of D. palmatum S. and D. ruyschiana L. originating from Yakutia. The results of initial studies revealed the presence of 114 compounds, of which 92 were identified for the first time in the genus Dracocephalum. New identified metabolites belonged to 17 classes, including 16 phenolic acids and their conjugates, 18 flavones, 5 flavonols, 2 flavan-3-ols, 1 flavanone, 2 stilbenes, 10 anthocyanins, 1 condensed tannin, 2 lignans, 6 carotenoids, 3 oxylipins, 2 amino acids, 3 sceletium alkaloids, 3 carboxylic acids, 8 fatty acids, 1 sterol, and 3 terpenes, along with 6 miscellaneous compounds. It was shown that extracts of D. palmatum are richer in the spectrum of polyphenolic compounds compared with extracts of D. ruyschiana, according to a study of the presence of these compounds in extracts, based on the results of mass spectrometric studies.

Sidastrum paniculatum (L.) Fryxell (Malvaceae): A Promising Source of Bioactive Sulfated Flavonoids Against Aedes aegypti L

Aedes aegypti L. is known as the most relevant vector mosquito for viruses such as yellow fever, chikungunya, dengue, and Zika, especially in places with unplanned urbanization, and erratic water supply. Plants used in folk medicine have become a useful source of active compounds with the potential to control the dissemination of Ae. aegypti. Compounds isolated from Malvaceae sensu lato have been previously reported as larvicides, repellents, and insecticides. Recent studies have demonstrated the anti Ae. aegypti activity of sulfated flavonoids, an uncommon type of flavonoid derivatives. This research reports the phytochemical investigation of Sidastrum paniculatum (L.) Fryxell, a Malvaceae species with the potential against Ae. aegypti. Chromatographic procedures resulted in the isolation of the compounds: stearic acid (1), N-trans-feruloyltyramine (2), acacetin (3), apigenin (4), tiliroside (5), along with the sulfated flavonoids: wissadulin (6), 7,4'-di-O-methyl-8-O-sulfate flavone (7), yannin (8), beltraonin (9a), 7-O-sulfate isoscutellarein (paniculatumin) (9b), and condadin (10). This is the first report of compound 7-O-sulfate isoscutellarein (9b). The structures were elucidated by spectroscopic analysis (NMR, LC-HRMS and FT-IR). The sulfated flavonoids identified were submitted to a ligand-based and structure-based virtual screening against two targets: 1YIY (from adult Ae. aegypti) and 1PZ4 (from Ae. aegypti larvae). The results indicated that when the O-sulfate group is bearing the position 7, the structures are potentially active in 1PZ4 protein. On the other hand, flavonoids with the O-sulfate group bearing position 8 were showed to be more likely to bind to the 1YIY protein. Our findings indicated that S. paniculatum is a promising source of sulfated flavonoids with potential against Ae. aegypti.

Research of Dracocephalum palmatum S. and Dracocephalum ruyschiana L. originating from Yakutia and identification of metabolites by tandem mass spectrometry

Dracocephalum palmatum Stephan and Dracocephalum ruyschiana L. contains a large number of target analytes, which are biologically active compounds. High performance liquid chromatography (HPLC) in combination with a BRUKER DALTONIKS ion trap (tandem mass spectrometry) was used to identify target analytes in extracts of D. palmatum Stephan and D. ruyschiana L., originating from Yakutia. The results of initial studies revealed the presence of 61 compounds, of which 53 were identified for the first time in genus Dracocephalum. These are flavones: Apigenin 8-C-pentoside-6-C-hexoside, Apigenin 7-sulfate; Chrysin 6-C-glucoside, Chrysin glucuronide; flavanols: Kaempferol, Dihydrokaempferol, Astragalin; flavan-3-ol (epi)Catechin, phenolic acids: Methylgallic acid; Hydroxy methoxy dimethylbenzoic acid; Ellagic acid; Caffeoylshikimic acid; Prolithospermic acid; 3,4-O-dicaffeoylquinic acid; salvianolic acid G; stilbenes pinosylvin and resveratrol; anthocyanins Petunidin, Pelargonidin-3-O-glucoside; Peonidin-3-O-glucoside; Cyanidin 3-(acetyl)hexose; perillic acid; lignans: Hinokinin, Dimethyl-secoisolariciresinol, Podophyllotoxin, carotenoids: Apocarotenal, 5,8-epoxy-alpha-carotene; etc.

The isolation of water-soluble natural products - challenges, strategies and perspectives

Covering period: up to 2019Water-soluble natural products constitute a relevant group of secondary metabolites notably known for presenting potent biological activities. Examples are aminoglycosides, β-lactam antibiotics, saponins of both terrestrial and marine origin, and marine toxins. Although extensively investigated in the past, particularly during the golden age of antibiotics, hydrophilic fractions have been less scrutinized during the last few decades. This review addresses the possible reasons on why water-soluble metabolites are now under investigated and describes approaches and strategies for the isolation of these natural compounds. It presents examples of several classes of hydrosoluble natural products and how they have been isolated. Novel stationary phases and chromatography techniques are also reviewed, providing a perspective towards a renaissance in the investigation of water-soluble natural products.

Isolation and In Silico Anti-COVID-19 Main Protease (Mpro) Activities of Flavonoids and a Sesquiterpene Lactone from Artemisia sublessingiana

The emergence of the COVID-19 pandemic declared the huge need of humanity for new and effective antiviral drugs. The reported antimicrobial activities of Artemisia sublessingiana encouraged us to investigate the ethanol extract of its aerial parts which led to the isolation of six flavonoids and a sesquiterpenoid. The structures of the isolated compounds were elucidated by EI-MS, 1D, and 2D NMR spectroscopic methods to be (1) eupatilin, (2) 3′,4′-dimethoxyluteolin, (3) 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone, (4) hispidulin, (5) apigenin, (6) velutin, and (7) sesquiterpene lactone 8α,14-dihydroxy-11,13-dihydromelampolide. The isolated compounds were in silico examined against the COVID-19 main protease (Mpro) enzyme. Compounds 1–6 exhibited promising binding modes showing free energies ranging from −6.39 to −6.81 (kcal/mol). The best binding energy was for compound 2. The obtained results give hope of finding a treatment for the COVID-19 pandemic.

Chemical Constituents from the Aerial Parts of Elsholtzia ciliata and Their Protective Activities on Glutamate-Induced HT22 Cell Death

A new phenolic glucoside, (7E,9E)-3-hydroxyavenalumic acid-3-O-[6'-O-(E)-caffeoyl]-β-d-glucopyranoside (1), and three new acetylated flavone glycosides, acacetin-7-O-[β-d-glucopyranosyl(1″″→2″)-4‴-O-acetyl-α-l-rhamnopyranosyl(1‴→6″)]-β-d-glucopyranoside (3), acacetin-7-O-[6″″-O-acetyl-β-d-glucopyranosyl(1″″→2″)-3‴-O-acetyl-α-l-rhamnopyranosyl(1‴→6″)]-β-d-glucopyranoside (5), and acacetin-7-O-[3″″,6″″-di-O-acetyl-β-d-glucopyranosyl(1″″→2″)-4‴-O-acetyl-α-l-rhamnopyranosyl(1‴→6″)]-β-d-glucopyranoside (7), as well as 34 known compounds (2, 4, 6, and 8-38) were isolated from the aerial parts of Elsholtzia ciliata. The chemical structures of the new compounds were determined by spectroscopic/spectrometric data interpretation using NMR and HRESIMS. The neuroprotective effect of the isolated compounds was evaluated by a cell viability assay on HT22 murine hippocampal neuronal cells. Among them, 23 compounds, including new substances 1 and 3, exhibited neuroprotective effects against glutamate-induced HT22 cell death. In particular, compounds 2, 16, 17, 20, 22, 28, 29, and 31 presented potent neuroprotective effects with EC₅₀ values of 1.5-8.3 μM.

Acacetin, a flavone with diverse therapeutic potential in cancer, inflammation, infections and other metabolic disorders

BACKGROUND

Acacetin is a di-hydroxy and mono-methoxy flavone present in various plants, including black locust, Damiana, Silver birch. Literature information revealed that acacetin exhibits an array of pharmacological potential including chemopreventive and cytotoxic properties in cancer cell lines, prevents ischemia/reperfusion/myocardial infarction-induced cardiac injury, lipopolysaccharide (LPS), 1-methyl-4-phenyl pyridinium ion (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced neuroinflammation, LPS and sepsis-induced lung injury, rheumatoid and collagen-induced arthritis, inhibit the microbial growth, obesity, viral-mediated infections as well as hepatic protection.

PURPOSE

This review highlights the therapeutic potential of acacetin, with updated and comprehensive information on the biological sources, chemistry, and pharmacological properties along with the possible mechanism of action, safety aspects, and future research opportunities.

STUDY DESIGN

The information was retrieved from various search engines, including Pubmed, SciFinder, Science direct, Inxight:drugs, Google scholar, and Meta cyc.

RESULT

The first section of this review focuses on the detailed biological source of acacetin, chromatographic techniques used for isolation, chemical characteristics, the method for the synthesis of acacetin, and the available natural and synthetic derivatives. Subsequently, the pharmacological activities, including anti-cancer, anti-inflammatory, anti-viral, anti-microbial, anti-obesity, have been discussed. The pharmacokinetics data and toxicity profile of acacetin are also discussed.

CONCLUSION

Acacetin is a potent molecule reported for its strong anti-inflammatory and anti-cancer activity, however further scientific evidence is essential to validate its potency in disease models associated with inflammation and cancer. There is limited information available for toxicity profiling of acacetin; therefore, further studies would aid in establishing this natural flavone as a potent candidate for research studies at clinical setup.

Effects of green synthesis of sulfur nanoparticles from Cinnamomum zeylanicum barks on physiological and biochemical factors of Lettuce (Lactuca sativa)

In this study, the effect of green synthesized sulfur nanoparticle (SNP) at different concentration (0, 0.01, 0.1, 1 and 10 mg/ml) on some physiological, phytochemical and biochemical traits of lettuce plants was investigated. For the first time, SNP were green synthesized using Cinnamomum zeylanicum barks extract. Our results indicated that the treatment of lettuce plants with 1 mg/ml of SNP improved the growth and photosynthetic parameters of lettuce plants than related control. Some other physiological parameters such as proline, glycine betaine and soluble sugars levels along with some phytochemical parameters like anthocyanin, total phenol, flavonoids and tannin contents were enhanced after treatment of the plants with same concentration of SNP. On the other hand, specific activity of antioxidant enzymes (catalase, ascorbate peroxidase and polyphenol oxidase) and stress markers level, MDA and H2O2 were reduced in the same treated lettuce plants. However, a concentration of 10 mg/ml of SNP exhibited toxicity on lettuce plants with inducing oxidative stress markers (H2O2 and MDA) and consequently reducing plant growth and biomass. This oxidative stress tend to diminish some physiological, phytochemical and biochemical parameters in treated lettuce plants. Overall, it can be concluded that the green synthesis SNP at an optimal concentration of 1 mg/ml improved physiological parameters in the lettuce plants making them potent to tolerate stressful conditions. However, higher concentration of SNP (10 mg/ml) indicated toxic effects on all of the physiological parameters.

Structural characterization of bioactive compounds in Cotula cinerea extracts by ultra-high-performance liquid chromatography with photodiode array and high-resolution time-of-flight mass spectrometry detectors

RATIONALE

Cotula cinerea of the Asteraceae family is a traditional Moroccan plant with various biological activities such as analgesic, cytotoxic and antioxidant effects which are often related to the presence of secondary metabolites. The present work aims to screen and identify the main phytochemicals compounds of Cotula cinerea extracts.

METHODS

A method was developed that coupled a rapid and simple ultra-high-performance liquid chromatography system with both photodiode array and high-resolution time-of-flight mass spectrometry detectors (UHPLC-PDA/TOF-HRMS) for the identification of the main secondary metabolites of three investigated extracts (hexane, AcOEt and n-BuOH).

RESULTS

A total of 30 phytocomponents pertaining to phenolic compounds and terpenoids have been detected, identified and quantified. Among these were previously reported free and conjugated coumaric and caffeic acids along with free and conjugated flavones and flavonols with kaempferol, quercetin, luteolin and apigenin aglycones. In addition, sulfated flavonoids were identified in the investigated extracts and are reported in this work for the first time in Cotula cinerea. The obtained results have been discussed in relation to the biological activities of the corresponding extracts.

CONCLUSIONS

This study proposed a practical strategy for rapidly screening and identifying secondary metabolites of Cotula cinerea and provided new information on the phytochemicals of this Saharan plant. This work has therefore provided useful results for further pharmacological studies and the design of new drugs based on this species and will facilitate the utilization of Cotula cinerea in the clinic and its safety evaluation. It is also hoped that the information presented here might stimulate further studies that will possibly lead to development of therapeutic agents from this plant.

Acute and repeated dose 28-day oral toxicity of Chrysobalanusicaco L. leaf aqueous extract

Chrysobalanus icaco L. is a native plant of Brazil used as a food source and traditionally for the treatment of various diseases. The aim of study was performed the phytochemical analysis by UPLC-DAD-ESI-QTOF-MS/MS, and evaluated acute and repeated dose oral toxicities of the C. icaco L. leaf aqueous extract (AECi). The acute toxicity study was performed using a dose of AECi 2000 mg/kg, while the repeated dose toxicity study, the AECi was administered daily at doses of 100, 200 and 400 mg/kg, for 28 days. Behavior and mortality of animals were observed during the test period and body weight, as well water and eating consumption. Hematological, biochemical parameters and histopathological examinations were carried out. Phytochemical analysis of the AECi revealed the presence of flavonoids and tannins. Oral single dose of 2000 mg/kg of AECi resulted in no mortalities or abnormal clinical signs. Studies of repeated dose toxicity promoted a reduction in the body weight of treated animals and an increase of hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in both, males and females. Histopathological analyzes showed alterations in the livers of animals treated with AECi. Thus, this study recommends the population take care when using this species, especially during prolonged periods.

Sulfated flavanones and dihydroflavonols from willow

Phytochemical profiling of a hybrid species of willow, Salix × alberti L. (S. integra Thunb. × Salix suchowensis W.C. Cheng ex G.Zhu) revealed four sulfated flavonoids, which were then isolated from young stem tissue. The structures of dihydroflavonols (flavanonols) taxifolin-7-sulfate (1) and dihydrokaempferol-7-sulfate (2) and flavanones, eridictyol-7-sulfate (3) and naringenin-7-sulfate (4) were elucidated through NMR spectroscopy and high-resolution mass spectrometry. The identified sulfated flavanones and dihydroflavonols have not been previously seen in plants, but the former have been partially characterised as metabolites in mammalian metabolism of dietary flavonoids. In addition to providing full spectroscopic characterisation of these metabolites for the first time, we also compared the in vitro antioxidant properties, via the DPPH radical scavenging assay, of the parent and sulfated flavanones, which showed that 7-sulfation of taxifolin and eriodictyol attenuates but does not remove anti-oxidant activity.

Chemical Constituents from the Aerial Parts of Agastache rugosa and Their Inhibitory Activities on Prostaglandin E2 Production in Lipopolysaccharide-Treated RAW 264.7 Macrophages

A new flavone glucoside, acacetin-7-O-(3″-O-acetyl-6″-O-malonyl)-β-d-glucopyranoside (1), two new phenolic glucosides, (3R,7R)-tuberonic acid-12-O-[6'-O-(E)-feruloyl]-β-d-glucopyranoside (14) and salicylic acid-2-O-[6'-O-(E)-feruloyl]-β-d-glucopyranoside (15), and two new phenylpropanoid glucosides, chavicol-1-O-(6'-O-methylmalonyl)-β-d-glucopyranoside (17) and chavicol-1-O-(6'-O-acetyl)-β-d-glucopyranoside(18), as well as 26 known compounds, 2-13, 16, and 19-31, were isolated from the aerial parts of Agastache rugose. The structures of the new compounds were established by spectroscopic/spectrometric methods such as HRESIMS, NMR, and ECD. The anti-inflammatory effect of the isolated compounds was evaluated by measuring their inhibitory activities on prostaglandin E₂ (PGE₂) in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. New compounds 1, 15, 17, and 18 inhibited LPS-induced PGE₂ production with IC₅₀ values of 16.8 ± 0.8, 33.9 ± 4.8, 14.3 ± 2.1, and 48.8 ± 4.4 μM, respectively. Compounds 5, 7, 9-11, 13, 19, 20, 22, and 27-30 showed potent inhibitory activities with IC₅₀ values of 1.7-8.4 μM.

Sulphated flavones and pregnane-type steroids from Helicteres viscida

In our search for anti-inflammatory constituents from Vietnamese plants, the methanolic extract of Helicteres viscida was found to exhibit inhibitory effect on LPS-induced NO production in RAW264.7 cells. Phytochemical investigation of this plant led to isolation of four sulphated flavones (1-4), including one new compound 5,3',4'-trihydroxy-7-methoxy-8-O-sulphate flavone (1), and two pregnane-type steroids (5 and 6), including one new compound 7-epi-heligenin B (5). Their structures were elucidated by 1D and 2D NMR as well as HR-QTOF-MS experiments. Among isolated compounds, heligenin B (6) exhibited potent inhibitory effect on LPS-induced NO production in RAW264.7 cells with IC₅₀ of 1.23 ± 0.05 µM. The activity of 6 was comparable to that of the positive control cardamonin.

Larvicidal Compounds Extracted from Helicteres velutina K. Schum (Sterculiaceae) Evaluated against Aedes aegypti L

Helicteres velutina K. Schum (Sterculiaceae), a member of Malvaceae sensu lato, is a Brazilian endemic plant that has been used by the indigenous tribe Pankarare as an insect repellent. A previous study has reported the isolation of terpenoids, flavonoids and pheophytins, in addition to the larvicidal activity of crude H. velutina extracts derived from the aerial components (leaves, branches/twigs, and flowers). The present study reports the biomonitoring of the effects of fractions and isolated compounds derived from H. velutina against A. aegypti fourth instar larvae. A crude ethanol extract was submitted to liquid–liquid extraction with hexane, dichloromethane, ethyl acetate and n-butanol to obtain their respective fractions. Larvicidal evaluations of the fractions were performed, and the hexane and dichloromethane fractions exhibited greater activities than the other fractions, with LC₅₀ (50% lethal concentration) values of 3.88 and 5.80 mg/mL, respectively. The phytochemical study of these fractions resulted in the isolation and identification of 17 compounds. The molecules were subjected to a virtual screening protocol, and five molecules presented potential larvicidal activity after analyses of their applicability domains. When molecular docking was analysed, only three of these compounds showed an ability to bind with sterol carrier protein-2 (1PZ4), a protein found in the larval intestine. The compounds tiliroside and 7,4′-di-O-methyl-8-O-sulphate flavone showed in vitro larvicidal activity, with LC₅₀ values of 0.275 mg/mL after 72 h and 0.182 mg/mL after 24 h of exposure, respectively. This is the first study to demonstrate the larvicidal activity of sulphated flavonoids against A. aegypti. Our results showed that the presence of the OSO₃H group attached to C-8 of the flavonoid was crucial to the larvicidal activity. This research supports the traditional use of H. velutina as an alternative insecticide for the control of A. aegypti, which is a vector for severe arboviruses, such as dengue and chikungunya.

Effects of Supercritical Carbon Dioxide Extraction (SC-CO2) on the content of tiliroside in the extracts from Tilia L. flowers

Tiliroside is one of the main flavonoid compounds responsible for a wide spectrum of biological activity of Tilia L. Up to now, several extraction techniques have been reported for extracting this compound from Tilia L. In this work for the first time supercritical carbon dioxide extraction was used for this purpose. Experiments were performed using supercritical carbon dioxide with 5% and 10% of ethanol as solvent, aiming a recovery content of tiliroside, temperature from 45 to 80°C, pressure from 100 to 220 bar and time from 20 to 60 minutes. The statistically generated optimum extraction conditions to obtain the highest content of tiliroside were established as: pressure of 200 bar, temperature 65°C and 45-50 minutes for 5% ethanol concentration and pressure of 220 bar, temperature 65°C and 15 minutes for 10% ethanol concentration.

A liquid chromatography-electrospray ionization-tandem mass spectrometry method (LC-ESI-MS/MS) was used to determine the content of tiliroside in the obtained extracts. In addition, the total phenolic (TPC) and flavonoid (TFC) content and antioxidant activity (DPPH• method) were determined.

Persulfated flavonoids accelerated re-endothelialization and improved blood compatibility for vascular medical implants

Drug-eluting stents (DESs) have been used for the treatment of cardiovascular diseases including stenosis. However, in-stent restenosis, thrombosis, and delayed re-endothelialization represent challenges for their clinical applications. Here, we demonstrate a novel work to overcome these limitations through surface modification technology. The cobalt-chromium (Co-Cr) surface was modified with antioxidants such as gallic acid (GA) and rutin (Ru) and the corresponding persulfates derivatives (i.e., GAS, and RuS) through a simple conjugation procedure. Various analyses tools such as ATR-FTIR, XPS, water contact angle, SEM, and AFM characterized the functionalized surface. The surface characterization confirmed that the antioxidant and the additional persulfates were successfully bonded to the Co-Cr surface. The results of in vitro endothelial cells proved that the persulfates derivatives showed the highest tendency to get rapid re-endothelialization especially RuS. In addition, it showed inhibition to smooth muscle cells (SMCs) as compared to control Co-Cr substrate. The persulfates modified substrates reduced the amount of adsorbed fibrinogen and albumin with higher stability to fetal bovine serum. Moreover, platelet study also demonstrated that Ru and RuS presented lower platelet adhesion with round shape morphology, whereas the control Co-Cr adhere and activate many platelets with pseudopodium morphology. Moreover, these modification processes did not cause any inflammatory responses. In conclusion, it is believed that the persulfates flavonoids have a great potential in the field of drug-eluting stents and blood contacting medical implants to improve blood compatibility, suppress SMCs, and get rapid re-endothelialization.

Optimization of Extraction Conditions for Determination of Tiliroside in Tilia L. Flowers Using an LC-ESI-MS/MS Method

Tiliroside exhibits a wide spectrum of effects on the human body; considering expensive synthesis of tiliroside, linden trees seem to be a good source of this compound. For the first time, 46 various extraction methods were developed to receive tiliroside from Tilia L., including ultrasound-assisted extraction, maceration, maceration with stirring, accelerated solvent extraction, and extraction under reflux. The effects of extraction techniques, solvents, additives, and temperature on the content of tiliroside were studied using analytical and statistical methods. A new, rapid, simple, sensitive, and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed to determine the content of tiliroside in Tilia L. flowers. The LC-ESI-MS/MS analysis demonstrated the highest content of tiliroside in Tilia L. flowers obtained using accelerated solvent extraction (ASE) where 70% ethanol with addition of 1% acetic acid was used as a solvent (7.400 ± 0.019 mg of tiliroside per g dry extract).The results showed that the extracts of Tiliae inflorescentia contained large amounts of tiliroside; therefore, they are good sources of this compound. Moreover, ASE was found to be superior to other extraction techniques due to its high efficiency as well as considerable saving of time and solvent.

New Sulphated Flavonoids and Larvicidal Activity of Helicteres velutina K. Schum (Sterculiaceae)

Helicteres velutina K. Schum (Sterculiaceae), commonly known in Brazil as ‘pitó’, is traditionally used by indigenous peoples as insecticides and repellents. The present work reports on the the phytoconstituents from aerial parts of H. velutina and evaluation of the larvicidal potential of its extract. The compounds were isolated using chromatographic techniques and identified by NMR, IR and LC-HRMS. This study led to the isolation of a fatty acid, one aliphatic alcohol, four chlorophyll derivatives, one steroid, triterpenes, a lignan, and flavonoids, highlighting the new compounds in the literature, 5,4′-di-hydroxy-7-methoxy-8-O-sulphate flavone (mariahine) (15a) and 5,3′-di-hydroxy-7,4′-dimethoxy-8-O-sulphate flavone (condadine) (15b). The work presented here contributes to the chemotaxonomic knowledge of the Sterculiaceae family by describing the occurrence of sulphated flavonoids in this family for the first time. The crude ethanolic extract of H. velutina featured robust larvicidal activity against Aedes aegypti larvae, showing that the extract can be useful as a domestic larvicide, just as indicated by traditional use, to combat A. aegypti, a vector insect of severe viral diseases, such as dengue and Zika.

A Review on the Dietary Flavonoid Tiliroside

Among flavonoid derivatives, tiliroside is a flavonoid contained in several edible plants or specific plant parts (fruits, leaves, or roots). These parts are often widely used as both food and medicines, in the treatment of various ailments and, in some cases, as food supplements. Considering the easy access to many publications concerning tiliroside and the lack of a review that summarizes the current progress in studies on its safety, efficacy, and presence in the plant kingdom, we present here a review paper on tiliroside and its principal derivatives. The paper also highlights the basic knowledge regarding this molecule, its derivatives, and the analytical approaches used for extraction and quantification, as well as reports on the biological activities against different key enzymes linked to various human diseases. The reported information is also devoted to highlighting the concept "learn from nature to discover new products," particularly in the development of new drugs, food supplements, and nutraceuticals, starting from a natural lead compound such as tiliroside and improving its biological activities (and selectivities) against a specific target for therapeutic purposes.

Protective Effect of Artemisia argyi and Its Flavonoid Constituents against Contrast-Induced Cytotoxicity by Iodixanol in LLC-PK1 Cells

Preventive effects and corresponding molecular mechanisms of mugwort (Artemisia argyi) extract and its flavonoid constituents on contrast-induced nephrotoxicity were explored in the present study. We treated cultured LLC-PK1 cells with iodixanol to induce contrast-induced nephrotoxicity, and found that A. argyi extracts ameliorated the reduction in cellular viability following iodixanol treatment. The anti-apoptotic effect of A. argyi extracts on contrast-induced nephrotoxicity was mediated by the inhibition of mitogen-activated protein kinase (MAPK) phosphorylation and the activation of caspases. The flavonoid compounds isolated from A. argyi improved the viability of iodixanol-treated cells against contrast-induced nephrotoxicity. Seven compounds (1, 2, 3, 15, 16, 18, and 19) from 19 flavonoids exerted a significant protective effect. Based on the in silico oral-bioavailability and drug-likeness assessment, which evaluate the drug potential of these compounds, compound 2 (artemetin) showed the highest oral bioavailability (49.55%) and drug-likeness (0.48) values. We further investigated the compound–target–disease network of compound 2, and proliferator-activated receptor gamma (PPAR-γ) emerged as a predicted key marker for the treatment of contrast-induced nephrotoxicity. Consequently, compound 2 was the preferred candidate, and its protective effect was mediated by inhibiting the contrast-induced inflammatory response through activation of PPAR-γ and inhibition of MAPK phosphorylation and activation of caspases.

Astragalin-induced cell death is caspase-dependent and enhances the susceptibility of lung cancer cells to tumor necrosis factor by inhibiting the NF-кB pathway

Flavonoids are naturally occurring polyphenolic compounds and are among the most promising anticancer agents. Here, we demonstrate that the flavonoid astragalin (AG), also known as kaempferol-3-O-β-D-glucoside, induces cell death. This was prevented by the caspase inhibitors z-DEVD-FMK and z-LEHD-FMK. AG-induced cell death was associated with an increase in the Bax:Bcl-2 ratio and amplified by the inhibition of extracellular signal-regulated kinase (ERK)-1/2 and Akt signaling. Meanwhile, AG suppressed LPS-induced NF-κB activation. Additional studies revealed that AG inhibited tumor necrosis factor-alpha (TNFα)-induced NF-κB activity. AG also potentiated TNFα-induced apoptosis in A549 cells. Furthermore, using a mouse xenograft model, we demonstrated that AG suppressed tumor growth and induced cancer cell apoptosis in vivo. Taken together, these results suggest that AG may be a promising cancer therapeutic drug that warrants further investigation into its potential clinical applications.

Sulphated Flavonoids: Biosynthesis, Structures, and Biological Activities

The great diversity of enzymatic reactions in plant secondary metabolism allows the continuous discovery of new natural compounds and derivatives. Flavonoids, for example, can be found as aglycone or as several sorts of glycosylated, acetylated, methylated, and sulphated derivatives. This review focuses on sulphated flavonoids, an uncommon group of flavonoid derivatives found in some plant families. This work presents a compilation of sulphated flavonoids and their natural sources reported in the literature. Biosynthetic aspects and biological activities have also been reviewed, showing that these particular kinds of natural compounds play an interesting role in plant metabolism, as well as being potential candidates for the development of new drugs.

Profiling of Phenolic Natural Products in the Seagrass Zostera noltei by UPLC-MS

Seagrasses are marine plants that play important ecological functions in coastal ecosystems. The species Zostera noltei is widely distributed along the European coasts thriving in a variety of environmental conditions. In this study, the phenolic natural products of Z. noltei have been analyzed quantitatively by using UPLC-MS. Plants from the Natural Park of the Bay of Cadiz (Spain) were shown to contain rosmarinic acid (1) and the flavonoids apigenin-7- O-glucoside (2), luteolin-7-sulfate (7), apigenin-7-sulfate (8), diosmetin-7-sulfate (9), and acacetin-7-sulfate (10). The analysis by UPLC-MS of extracts allowed the quantification of all the compounds and evidenced the intraspecific variations in the profile of natural products among plants collected at different dates and locations within the Bay. The flavonoids 2, and 7-10 were present in all the analyzed samples with a total flavonoid content in the range 12.8–72.3 mg/g dry wt, while rosmarinic acid (1) was only present in some samples, reaching up to 19.6 mg/g dry wt. A distinctive feature of plants from the Bay of Cadiz is the common presence of apigenin-7-sulfate (8) as major flavonoid, differing from plants from other regions whose major flavonoid is diosmetin-7-sulfate (9).

Regioselective ortho-Hydroxylations of Flavonoids by Yeast

Natural flavonoids, such as naringenin, hesperetin, chrysin, apigenin, luteolin, quercetin, epicatechin, and biochanin A, were subjected to microbiological transformations by Rhodotorula glutinis. Yeast was able to regioselectively C-8 hydroxylate hesperetin, luteolin, and chrysin. Naringenin was transformed to 8- and 6-hydroxyderivatives. Quercetin, epicatechin, and biochanin A did not undergo biotransformation. A metabolic pathway for the degradation of chrysin has been elucidated. The metabolism of chrysin proceeds via an initial C-8 hydroxylation to norwogonin, followed by A-ring cleavage to 4-hydroxy-6-phenyl-2H-pyran-2-one.

Sulfation pathways in plants

Plants take up sulfur in the form of sulfate. Sulfate is activated to adenosine 5'-phosphosulfate (APS) and reduced to sulfite and then to sulfide when it is assimilated into amino acid cysteine. Alternatively, APS is phosphorylated to 3'-phosphoadenosine 5'-phosphosulfate (PAPS), and sulfate from PAPS is transferred onto diverse metabolites in its oxidized form. Traditionally, these pathways are referred to as primary and secondary sulfate metabolism, respectively. However, the synthesis of PAPS is essential for plants and even its reduced provision leads to dwarfism. Here the current knowledge of enzymes involved in sulfation pathways of plants will be summarized, the similarities and differences between different kingdoms will be highlighted, and major open questions in the research of plant sulfation will be formulated.