Flavonol glycosides from Eschscholtzia californica

Chemical constituents of the aerial parts of Mitracarpus hirtus (L.) DC (Rubiaceae)

A phytochemical investigation of the aerial parts of Mitracarpus hirtus afforded thirteen compounds, including a new naphthoquinone di-glycoside (1), three isopentenyl isoflavones (2-4), four flavonoids (5-8), three iridoid glycosides (9 - 11) and two coumarins (12 and 13). Their structures were elucidated based on extensive spectroscopic analyses, chemical methods, and the comparison with the literature. Among them, compound 1 possesses a 2-(3-methylnaphthalen-2-yl)acetic acid core with two glucosyl groups, compounds 2-4 are the first three representatives from the Rubiaceae family, and compounds 9-11 and 13 were isolated from Mitracarpus genus for the first time. Additionally, compounds 2-4 displayed potent antibacterial activities against Helicobacter pylori G27/HP159/JRES00015 (MIC = 4-16 μg/mL) , comparable to metronidazole. To date, wighteone (2) is the most active isoflavone with favourable predicted ADMET properties reported against H. pylori.

New ψ-Santonin Derivatives from Crossostephium chinense and Their Anti-Proliferative Activities against Leishmania major and Human Cancer Cells A549

Previously, we reported two cytotoxic ψ-santonin-amino acid conjugates isolated from the EtOAc layer of Crossostephium chinense. However, a further phytochemical investigation seems to be required because of the few reports of similar derivatives. In this study, we targeted the 1-BuOH layer, which resulted in the isolation of seven new ψ-santonin derivatives (1-7) together with ten known compounds (8-17). The structures of 1-7 were elucidated based on spectroscopic methods, including 1D and 2D NMR experiments (1H, 13C, DEPT, COSY, HSQC, and HMBC), IR spectrum, and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). The stereochemistry of new compounds was confirmed by NOESY and ECD calculations. All isolated compounds were evaluated by in vitro experiments for their anti-proliferative activities against Leishmania major, human lung cancer cell line A549, and Vero cells. As a result, most of the ψ-santonin derivatives, especially 1-5, showed significant cytotoxicity against L. major with a lower IC50 than the positive control we used (miltefosine).

Antioxidant and Anti-Aging Phytoconstituents from Faucaria tuberculosa: In Vitro and In Silico Studies

Research targeting natural cosmeceuticals is now increasing due to the safety and/or limited side effects of natural products that are highly valued in cosmetology. Within a research program exploring botanical sources for valuable skincare antioxidant components, the current study investigated the phytochemical content and the biological potential of Faucaria tuberculosa. Phytochemical investigation of F. tuberculosa extract resulted in purification and characterization of six phytoconstituents, including a new one. The structure of the new constituent was elucidated as (-) catechin-(2→1',4→2')-phloroglucinol (4). The structural identity of all isolated compounds were confirmed on the basis of extensive physical and spectral (1D, 2D-NMR and HRESIMS) investigations. The ethanolic extract exhibits a rich content of total phenolics (TPC) and total flavonoids (TFC), estimated as 32 ± 0.034 mg GAE/g and 43 ± 0.004 mg RE/g, respectively. In addition, the antioxidant (ABTS and FRAP), antihyaluronidase and antityrosinase activities of all purified phytoconstituents were evaluated. The results noted (-) catechin-(2→1',4→2') phloroglucinol (4) and phloroglucinol (1) for their remarkable antioxidant activity, while isorhamnetin 3-O-rutinoside (3) and 3,5-dihydroxyphenyl β-D-glucopyranoside (2) achieved the most potent inhibitory activity against tyrosinase (IC50 22.09 ± 0.7 µM and 29.96 ± 0.44 µM, respectively) and hyaluronidase enzymes (IC50 49.30 ± 1.57 µM and 62.58 ± 0.92, respectively) that remarkably exceeds the activity of the standard drugs kojic acid (IC50 = 65.21 ± 0.47 µM) and luteolin, (IC50 = 116.16 ± 1.69 µM), respectively. A molecular docking study of the two active compounds (3 and 2) highlighted their high potential to bind to the active sites of the two enzymes involved in the study.

Antimicrobial and antioxidant properties and quantitative screening of phytochemicals of Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures

The antioxidant and antimicrobial activities of Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures against a range of foodborne bacteria were investigated to determine the major components and to analyse the action spectrum and antimicrobial effectiveness of the extracts. Results demonstrated a significant antioxidant activity of Fraxinus excelsior L. and a lower activity of Eschscholtzia californica Cham. and a good chemical phenolic composition with the highest content of flavonoids. The Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures demonstrated a middle-high antimicrobial activity against, respectively, 66.67% and 43.33% of all tested bacteria. The inhibitory activity showed a moderate effect on the growth of the sensitive strains in presence of extracts minimum inhibitory concentration. The synergistic actions of bioactive compounds detected in the extracts might be on the basis of antioxidant and biological activities observed and should be used in pharmaceutical, food preservation, alternative medicine and natural therapies fields.

An Investigation of the Anti-Depressive Properties of Phenylpropanoids and Flavonoids in Hemerocallis citrina Baroni

The World Health Organization predicts that over the next several years, depression will become the most important mental health issue globally. Growing evidence shows that the flower buds of Hemerocallis citrina Baroni (H. citrina) possess antidepressant properties. In the search for new anti-depression drugs, a total of 15 phenylpropanoids and 22 flavonoids were isolated and identified based on spectral data (1D and 2D NMR, HR-ESI-MS, UV) from H. citrina. Among them, compound 8 was a novel compound, while compounds 1–4, 6, 9, 10, 15, 17, 24–26, 28, and 37 were isolated for the first time from Hemerocallis genus. To study the antidepressant activity of phenylpropanoids and flavonoids fractions from H. citrina, macroporous resin was used to enrich them under the guidance of UV characteristics. UHPLC-MS/MS was applied to identify the constituents of the enriched fractions. According to behavioral tests and biochemical analyses, it showed that phenylpropanoid and flavonoid fractions from H. citrina can improve the depressive-like mental state of chronic unpredictable mild stress (CUMS) rats. This might be accomplished by controlling the amounts of the inflammatory proteins IL-6, IL-1β, and TNF-α in the hippocampus as well as corticosterone in the serum. Thus, the monomer compounds were tested for their anti-neuroinflammatory activity and their structure–activity relationship was discussed in further detail.

Bioactive compounds and therapeutic role of Brassica oleracea L. seeds in rheumatoid arthritis rats via regulating inflammatory signalling pathways and antagonizing interleukin-1 receptor action

CONTEXT

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by aggressive and systematic polyarthritis.

OBJECTIVE

The present study aimed to isolate and identify the phenolic constituents in Brassica oleracea L. (Brassicaceae) seeds methanolic extract and evaluates its effect against rheumatoid arthritis in rats referring to the new therapy; interleukin-1 receptor antagonist (IL-1RA).

MATERIALS AND METHODS

The GC/MS profiling of the plant was determined. Arthritis induction was done using complete Freund's adjuvant. Arthritis severity was assessed by percentage of edema and arthritis index. IL-1 receptor type I gene expression, interleukin-1β (IL-1β), oxidative stress markers, protein content, inflammatory mediators, prostaglandin-E2 (PGE2), genetic abnormalities and the histopathological features of ankle joint were evaluated.

RESULTS

For the first time twelve phenolic compounds had been isolated from the seeds extract. Treatment with extract and IL-1RA improved the tested parameters by variable degrees.

CONCLUSIONS

RA is an irreversible disease, where its severity increases with the time of induction. Brassica oleracea L. seeds extract is considered as a promising anti-arthritis agent. IL-1 RA may be considered as an unusual therapeutic agent for RA disease. More studies are needed to consider the seeds extract as a nutraceutical agent and to recommend IL-1RA as a new RA drug.

Flavonoids from the peels of Citrus unshiu Markov. and their inhibitory effects on RANKL-induced osteoclastogenesis through the downregulation of c-Fos signaling in vitro

Phytochemical investigation of Citrus unshiu peels led to the isolation of eight new flavonols (7-9, 11-15) and sixteen known compounds (1-6, 10, 16-24). Their structures were elucidated using spectroscopic analysis (1D, 2D NMR, and HR-MS). Besides, all isolated compounds (1-24) were evaluated for their inhibitory effects on receptor activator of RANKL-induced osteoclastogenesis in BMMs. Among them, dimethylmikanin (1), quercetogetin (2), 3,3',4',5,7,8-hexamethoxyflavone (3), 3-methoxynobiletin (4) showed a significant inhibitory effect on RANKL-induced osteoclast differentiation at a concentration of 10 μM. Moreover, 3-methoxynobiletin (4) suppressed RANKL-induced osteoclastogenesis by decreasing the number of osteoclasts and osteoclast actin-ring formation in a dose-dependent manner without causing any cytotoxic effects on BMMs. At the molecular level, 3-methoxynobiletin (4) inhibited RANKL-induced c-Fos expression and subsequently NFATc1 activation, as well as the expression of osteoclastogenesis-related marker genes c-Src and CtsK. These findings suggested that 3-methoxynobiletin (4) attenuated osteoclast differentiation by inhibiting RANKL-mediated c-Fos signaling and that it may have therapeutic potential for treating or preventing bone resorption-related diseases, such as osteoporosis.

Flavonol glycosides from Fissistigma maclurei

Two new flavonol glycosides, fissmacosides A (1) and B (2) along with two known flavonol glycosides, kaempferol 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside (3) and kaempferol 3-O-β-d-glucopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→6)-[4-(E)-feruloyl]-β-d-galactopyranoside (4) were isolated from the methanol extract of the leaves of Fissistigma maclurei Merr. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-, 2D-NMR, and MS data.

Chemotypic variation of non-volatile constituents of Artemisia afra (African wormwood) from South Africa

Artemisia afra (African wormwood) is a popular medicinal plant of southern Africa and is an excellent candidate for commercialisation. This current study was aimed at exploring the phytochemistry and chemical variation of non-volatile compounds within wild populations of A. afra, and developing chromatographic quality control protocols for raw materials based on the identification of marker compounds. Chromatographic data, from samples representing 12 distinct populations, were obtained using liquid chromatography-mass spectrometry. An untargeted chemometric approach revealed three clusters. Marker compounds for each cluster, revealed through discriminant analysis, were isolated and identified using NMR spectroscopy, as acacetin (1) (Group 1), chrysoeriol (2) (Group 2), and 3,5-di-O-caffeoylquinic acid (3) and scopoletin (4) (Group 3). In addition, (3) and rutin (5), (both reported for the first time from A. afra), and (1), (2), (4) and 4-caffeoylquinic acid (6) were established as reliable markers for species identification, since they were abundant in most samples. Quantitative analysis using a validated method established (4) as the dominant compound in the samples (1080-19,600 μg/g dry weight (d.w.)), followed by (5) (49.5-2490 μg/g d.w.). A high performance thin layer chromatography (HPTLC) method was developed. The Rf values and colours of the bands corresponding to the marker compounds were recorded so that these compounds could be easily identified for quality control purposes. Multivariate analysis of the data using the rTLC online application confirmed the presence of different chemical groupings within the samples. It was deduced that quantitative, rather than qualitative differences, characterised the samples. Future research should focus on comparing the efficacy of the various chemical clusters in multi-target biological assays aligned to the traditional use of the plant.

Isolation and evaluation of trypanocidal activity of sesquiterpenoids, flavonoids, and lignans in Artemisia sieversiana collected in Mongolia

Artemisia sieversiana is an annual herbaceous plant distributed throughout Central and East Eurasia and is regarded as an undesirable forage plant in Mongolia. It affects livestock, so information about its chemical composition is needed. We isolated three new sesquiterpenoids (1-3) and known compounds from A. sieversiana and investigated their activities. The absolute configuration of 1 was established using single-crystal X-ray diffraction crystallography, and its configuration differed from those of reported compounds with similar structures. Two additional new sesquiterpenoids (2 and 3) with similar structures were identified, and their configurations were determined. The trypanocidal activities of the isolated compounds (1-18) against Trypanosoma congolense and the pathogen responsible for fatal trypanosomosis in animals were estimated. Flavonoids and lignans were identified as active compounds with IC₅₀ values ranging from 2.9 to 90.2 µM.

New antimicrobial and cytotoxic benzofuran glucoside from Senecio glaucus L

The ethyl acetate fraction of the dried aerial parts of Senecio glaucus L. exhibited significant antimicrobial activity against some of selected bacteria and fungi. Also, it showed potent cytotoxicity against PANC-1 cancer cell lines under glucose deficient medium. The ethyl acetate fraction was subjected to different chromatographic techniques for isolation of the bioactive compounds. A new benzofuran glucoside; 2,3-dihydro-3β-hydroxyeuparin 3-O-glucopyranoside (1) was isolated. Additionally, two known flavonoid compounds isorhamentin 3-O-β-D-glucoside (2), and isorhamentin 3-O-β-D-rutinoside (3) were first identified in S. glaucus. Compound 1 exhibited potent antimicrobial activities against two Gram-positive bacteria, one Gram-negative bacteria, and two fungi. Also, it displayed potent cytotoxic activity against PANC-1 cancer cell lines under glucose deficient medium (IC50 7.5 μM). However, the isolated flavonoid glycosides (2 & 3) showed moderate antimicrobial activities against two Gram-positive bacteria, two Gram-negative bacteria, four fungi, and did not show any cytotoxic activity against PANC-1.

Two New Flavonoids from the Leaves of Baccharis oblongifolia (Ruiz and Pav.) Pers. (Asteraceae)

In this work, two new flavonoids, oblongifolioside A (1) and oblongifolioside B (2), along with eight known compounds (3–10), are isolated from the leaves of Baccharis oblongifolia (Asteraceae). The new structures are established through spectroscopic data and the known compounds are identified by comparison with data reported in the literature. The compounds (1–10) are evaluated in relation to their antiradical properties. Compounds 1 and 2 are found to exhibit high antiradical activity compared to their respective non-acylated flavonoids.

Three new flavonol glycosides from Fissistigma pallens

Three new flavonol glycosides, fissflavosides A-C (1-3), together with six known flavonol glycosides, kaempferol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside (4), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (5), kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (6), rhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (7), rutin (8), and isorhamnetin 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside (9) were isolated from the methanol extract of the Fissistigma pallens leaves. Their chemical structures were determined by 1D-, 2D-NMR, and MS data as well as in comparison with reported data in the literature. Compounds 1-9 showed weak cytotoxic activity on three human cancer cell lines, HT-29, A-2058, A-549 with IC₅₀ ranging from 134.6 to 162.6 µM. In addition, the antioxidant capacities of compounds were also tested by ORAC assay. All compounds showed significant antioxidant with trolox equivalents ranging from 4.4 to 8.6 µM at the concentration of 1.0 µM. The results indicated 7 and 8 having meaningful reducing capacity of copper (I) ions of 2.7 to 6.9 µM at the concentrations of 1 and 2 µM.

Chemical Constituents from Ethanoic Extracts of the Aerial Parts of Leea aequata L., a Traditional Folk Medicine of Myanmar

We aimed at reporting the chemical constituents and antimicrobial activities of Leea aequata L., a traditional folk medicine used in Myanmar for the treatment of wounds and skin diseases. A new neolignan, (7S,8R)-9'-O-acetylcedrusin (1), a new lactam, (3S,4S)-4-chloro-3-hydroxypiperidin-2-one (2), along with 21 known compounds, including five lignans (3-7), four flavonoid glycosides (8-11), and others (12-23), were isolated from the ethanoic extract of the aerial parts of L. aequata. The structures of the new compounds were determined by NMR, MS, and ECD spectra. For all the antimicrobial tests of the 23 compounds, only 3,4,5-trihydroxybenzoic acid ethyl ester (17) showed weak inhibitory activities against Escherichia coli and Salmonella enterica subsp. enterica.

Chemical Constituents of Phoebe poilanei and Their Cytotoxic Activity

Two new flavonol glycosides, rhamnocitrin 3- O-α-L-rhamnopyranosyl-(1→6)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (1) and quercetin 3- O-6- Z- p-coumaroyl-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranoside (2), along with 3 flavonol glycosides, isoquercitrin (3), rutin (4), and quercetin 3- O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (5), and two known sesquiterpenes, alismol (6) and spathulenol (7), were isolated from the leaves of Phoebe poilanei Kosterm. Their chemical structures were elucidated by analyses of their high-resolution electrospray ionization mass spectral data and nuclear magnetic resonance spectral data and comparison with those reported in the literature. Two sesquiterpenes 6 and 7 were found to exhibit moderate cytotoxic activity with IC50 values ranging from 21.6 to 29.8 µM.

Antimicrobial activities of flavonoid glycosides from Graptophyllum grandulosum and their mechanism of antibacterial action

BACKGROUND

The search for new antimicrobials should take into account drug resistance phenomenon. Medicinal plants are known as sources of potent antimicrobial compounds including flavonoids. The objective of this investigation was to evaluate the antimicrobial activities of flavonoid glycosides from Graptophyllum grandulosum, as well as to determine their mechanism of antibacterial action using lysis, leakage and osmotic stress assays.

METHODS

The plant extracts were prepared by maceration in organic solvents. Column chromatography of the n-butanol extract followed by purification of different fractions led to the isolation of five flavonoid glycosides. The antimicrobial activities of extracts/compounds were evaluated using the broth microdilution method. The bacteriolytic activity was evaluated using the time-kill kinetic method. The effect of extracts on the red blood cells and bacterial cell membrane was determined by spectrophotometric methods.

RESULTS

Chrysoeriol-7-O-β-D-xyloside (1), luteolin-7-O-β-D-apiofuranosyl-(1 → 2)-β-D-xylopyranoside (2), chrysoeriol-7-O-β-D-apiofuranosyl-(1 → 2)-β-D-xylopyranoside (3), chrysoeriol-7-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-(4"-hydrogeno sulfate) glucopyranoside (4) and isorhamnetin-3-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside (5) were isolated from G. grandulosum and showed different degrees of antimicrobial activities. Their antibacterial activities against multi-drug-resistant Vibrio cholerae strains were in some cases equal to, or higher than those of ciprofloxacin used as reference antibiotic. The antibacterial activities of flavonoid glycosides and chloramphenicol increased under osmotic stress (5% NaCl) whereas that of vancomycin decreased under this condition. V. cholerae suspension treated with flavonoid glycosides, showed a significant increase in the optical density at 260 nm, suggesting that nucleic acids were lost through a damaged cytoplasmic membrane. A decrease in the optical density of V. cholerae NB2 suspension treated with the isolated compounds was observed, indicating the lysis of bacterial cells. The tested samples were non-toxic to normal cells highlighting their good selectivity index.

CONCLUSIONS

The results of the present study indicate that the purified flavonoids from G. glandulosum possess antimicrobial activities. Their mode of antibacterial activity is due to cell lysis and disruption of the cytoplasmic membrane upon membrane permeability.

Antigenotoxic properties of Paliurus spina-christi Mill fruits and their active compounds

Background

Paliurus spina-christi Mill. (PS) fruits are widely used for different medical purposes in Turkey. Like in many medicinal herbs the studies concerning their activity, the activities of PS are also not well clarified. The aim of this study is to evaluate the antigenotoxicity of the compounds isolated and identified from the extracts of PS fruits.

Methods

The active compounds were separated, isolated, and determined by chromatographic methods and their structural elucidation was performed by Nuclear Magnetic Resonance (NMR) methods. The compounds were obtained from either ethyl acetate (EA) or n-butanol extracts. The cytotoxicities of the compounds using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the antigenotoxic activities of the compounds using the alkaline single cell gel electrophoresis techniques (comet assay) were evaluated in Chinese hamster lung fibroblast (V79) cell lines.

Results

The isolated major compounds were identified as (+/−) catechins and gallocatechin from EA fraction and rutin from n-butanol fraction of PS fruits. Their chemical structures were identified by ¹H-NMR, ¹³C-NMR, HMBC, and HMQC techniques. Half-maximal inhibitory concentration of catechins, gallocatechin, and rutin were found to be 734 μg/mL, 220 μg/mL, and 1004 μg/mL, respectively. The methanolic extract of PS (1-100 μg/mL) alone did not induce DNA single-strand breaks while catechins (1-100 μg/mL), gallocatechin (1-50 μg/mL), and rutin (1-50 μg/mL) significantly reduced H₂O₂-induced DNA damage.

Conclusion

It has been suggested that PS fruits and their compounds catechins, gallocatechin and rutin may have beneficial effects in oxidative DNA damage. It seems that PS fruits may be used in protection of the disorders related to DNA damage.

Effects of Hepatoprotective Compounds from the Leaves of Lumnitzera racemosa on Acetaminophen-Induced Liver Damage in Vitro

Phytochemical investigation of the n-BuOH fraction of the mangrove plant Lumnitzera racemosa WILLD. (Combretaceae) led to the isolation of one new flavonoid glycoside; myrcetin 3-O-methyl glucuronate (1), one new phenolic glycoside; lumniracemoside (2) and one new aliphatic alcohol glycoside; n-hexanol 1-O-rutinoside (3), in addition to seven known compounds (4-10). The structures of these compounds were determined by spectroscopic analyses (UV, IR, high resolution-electrospray ionization (HR-ESI)-MS, one- and two-dimensional (1D- and 2D)-NMR). Compound 7 showed the highest hepatoprotective activity against acetaminophen-induced hepatotoxicity using human HepG2 cells at protection % value of 34.2±3.1%, while compounds 1, 2, 3, 6, and 9 showed weak to moderate hepatoprotective activity (11.6-18.9%). Almost all of these compounds showed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity compared with the standard Trolox. These results suggest the usefulness of this plant extract and the isolated compounds as promising hepatoprotective agents.

Chemical constituents of Solanum coagulans and their antimicrobial activities

The present study aimed at determining the chemical constituents of Solanum coagulans and their antimicrobial activities. The compounds were isolated by various chromatographic techniques and their structures were elucidated on the basis of extensive spectroscopic analysis, chemical methods, and comparison with reported spectroscopic data. One new phenolic glycoside, methyl salicylate 2-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1), together with 12 known compounds (2-13), were isolated from the aerial parts of Solanum coagulans. Compound 1 was a new phenolic glycoside, and 2-6 were isolated from Solanum genus for the first time. The antimicrobial activities of the isolated compounds were also evaluated. Compound 7 showed remarkable antifungal activity against T. mentagrophytes, M. gypseum and E. floccosum with MIC values being 3.13, 1.56 and 3.13 μg·mL(-1), respectively.

Phenolic Compounds from the Flowers of Bombax malabaricum and Their Antioxidant and Antiviral Activities

Three new phenolic compounds 1-3 and twenty known ones 4-23 were isolated from the flowers of Bombax malabaricum. Their chemical structures were elucidated by spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D- and 2D-NMR) and chemical reactions. The antioxidant capacities of the isolated compounds were tested using FRAP and DPPH radical-scavenging assays, and compounds 4, 6, 8, 12, as well as the new compound 2, exhibited stronger antioxidant activities than ascorbic acid. Furthermore, all of compounds were tested for their antiviral activities against RSV by the CPE reduction assay and plaque reduction assay. Compounds 4, 10, 12 possess in vitro antiviral activities, and compound 10 exhibits potent anti-RSV effects, comparable to the positive control ribavirin.

Modulatory Effects of Eschscholzia californica Alkaloids on Recombinant GABAA Receptors

The California poppy (Eschscholzia californica Cham.) contains a variety of natural compounds including several alkaloids found exclusively in this plant. Because of the sedative, anxiolytic, and analgesic effects, this herb is currently sold in pharmacies in many countries. However, our understanding of these biological effects at the molecular level is still lacking. Alkaloids detected in E. californica could be hypothesized to act at GABAA receptors, which are widely expressed in the brain mainly at the inhibitory interneurons. Electrophysiological studies on a recombinant α 1 β 2 γ 2 GABAA receptor showed no effect of N-methyllaurotetanine at concentrations lower than 30 μM. However, (S)-reticuline behaved as positive allosteric modulator at the α 3, α 5, and α 6 isoforms of GABAA receptors. The depressant properties of aerial parts of E. californica are assigned to chloride-current modulation by (S)-reticuline at the α 3 β 2 γ 2 and α 5 β 2 γ 2 GABAA receptors. Interestingly, α 1, α 3, and α 5 were not significantly affected by (R)-reticuline, 1,2-tetrahydroreticuline, codeine, and morphine-suspected (S)-reticuline metabolites in the rodent brain.

Chemical constituents from Kandelia candel with their inhibitory effects on pro-inflammatory cytokines production in LPS-stimulated bone marrow-derived dendritic cells (BMDCs)

Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), including one new sesquiterpene glycoside, kandelside (1), three megastigman glycoside compounds (7-9), 16 known phenolic compounds (2-6 and 10-19). Structures of the isolated compounds were elucidated based on spectral data comparison with reported values. Isolated compounds were also evaluated for their inhibitory effects on the production of pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among these compounds, compound 9 exhibited strong inhibitory activity against IL-6 production (IC50=0.07 ± 0.05 μM) and moderate inhibitory activity against TNF-α production (IC50=49.86 ± 1.02 μM), but exhibited no activity on IL-12 p40 production. Compounds 5 and 6 significantly inhibited IL-12 p40, IL-6, and TNF-α production with IC50 values of 11.68 ± 0.38, 44.52 ± 1.08, and 28.73 ± 0.96 μM, respectively.

Carboxymethyl- and carboxyl-catechins from ripe Pu-er tea

Ripe Pu-er tea, a special microbial postfermented tea originated from Yunnan Province, China, since ancient times, is made from green Pu-er tea prepared from the leaves of Camellia sinensis var. assamica (Theaceae). Chemical investigation on thearubigin (n-BuOH-soluble) fraction of the commercial ripe Pu-er tea, led to the identification of four new flavan-3-ol derivatives, 8-carboxymethyl-(+)-catechin (1), 8-carboxymethyl-(+)-catechin methyl ester (2), 6-carboxymethyl-(+)-catechin (3), and 6-carboxyl-(-)-gallocatechin (4), together with 18 known compounds, including other three flavan-3-ol derivatives (5-7), 10 flavonoid glycosides (8-17), two hydrolyzable tannins (18 and 19), two quinic acid derivatives (20-21), and a purine alkaloid (22). Flavonoid glycosides 8-11 are reported from tea plants for the first time. The thearubigin fraction of ripe Pu-er tea was qualitatively analyzed by HPLC, and gallic acid was found to be the major component. Compounds 4, 6-17, 21 and 22 were tested for their acute activities on insulin sensitivity in differentiated 3T3-L1 adipocytes, but none of them showed significant bioactivity at a concentration of 10 μM.

Structure of constituents isolated from the flower buds of Cananga odorata and their inhibitory effects on aldose reductase

Three new terpenoid derivatives, canangaterpenes IV-VI, were isolated from the flower buds of Cananga odorata, cultivated in Thailand, together with eight known flavonoids. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of the isolated compounds on aldose reductase were also investigated. Several terpenoid derivatives and flavonoids were shown to inhibit aldose reductase.

Polyacetylenes and anti-hepatitis B virus active constituents from Artemisia capillaris

Three new polyacetylenes, 8-(Z)-decene-4, 6-diyne-1, 3, 10-triol (1), 1, 3S, 8S-trihydroxydec-9-en-4, 6-yne (2), 3S, 8S-dihydroxydec-9-en-4, 6-yne 1-O-β-D-glucopyranoside (3), and one new glucosyl caffeoate, 1-O-ethyl-6-O-caffeoyl-β-D-glucopyranose (4), together with 34 known compounds were isolated from Artemisia capillaris. The structures of the new compounds were determined by extensive spectroscopic analyses including 1D and 2D NMR, HRESIMS, [α]D and CD experiments. Among them, 19 compounds showed activity inhibiting HBsAg secretion; 20 compounds showed activity inhibiting HBeAg secretion; and 25 compounds possessed inhibitory activity against HBV DNA replication according to our anti-HBV assay on HepG 2.2.15 cell line in vitro. The most active compound 12 could inhibit not only the secretions of HBsAg and HBeAg, but also HBV DNA replication with IC50 values of 15.02 μM (SI=111.3), 9.00 μM (SI=185.9) and 12.01 μM (SI=139.2).

Identification and biological evaluation of flavonoids from the fruits of Prunus mume

This Letter describes the identification of potent antioxidant and anti-osteoporosis agents from the fruits of Prunus mume. From the methanol extract, a novel flavan dimer, characterized as 2β,3β-epoxy-5,7,4'-trihydroxyflavan-(4α→8)-epicatechin (1), was isolated along with five known flavonoids (2-6). Their structures were determined based on extensive spectroscopic analysis, including IR, HRESIMS, 1D- and 2D-NMR, and CD spectra. The antioxidant activities of compounds 1-6 were evaluated in terms of their peroxyl radical-scavenging (Trolox equivalent) and reducing capacities. All isolates showed potent peroxyl radical-scavenging and reducing activities at concentrations of 1-10 μM. Among them, compounds 1 and 2 were the most active at 1 μM. Anti-osteoporosis activities were investigated using both murine osteoblastic MC3T3-E1 cells and osteoclastic RAW 264.7 cells. Compounds 2, 3, and 6 significantly stimulated the differentiation of osteoblastic MC3T3-E1 cells to increase collagen synthesis or mineralization functions of osteoblasts. Compounds 1, 3, 4, and 6 significantly suppressed tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastic RAW 264.7 macrophage cells.

Inhibitory effects of the constituents of Hippophae rhamnoides on 3T3-L1 cell differentiation and nitric oxide production in RAW264.7 cells

Three new flavonol glycosides, hippophaeosides A-C (1-3), together with 27 known constituents, were isolated from Hippophae rhamnoides L. leaves. Their structures were determined by spectroscopic analyses. Their inhibitory activities on 3T3-L1 preadipocyte differentiation and triglyceride accumulation in maturing adipocytes, and nitric oxide production in RAW264.7 cells were examined.

Medicinal flowers. XXXVIII. structures of acylated sucroses and inhibitory effects of constituents on aldose reducatase from the flower buds of Prunus mume

The methanolic extract from the flower buds of Prunus mume, cultivated in Zhejiang province, China, showed an inhibitory effect on aldose reductase. From the methanolic extract, five new acylated sucroses, mumeoses F-J, were isolated together with 29 known compounds. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of the isolated compounds on aldose reductase were also investigated. Acylated quinic acid analogs, which are one of the major compounds of the flower buds of P. mume, were shown to substantially inhibit aldose reductase. In particular, mumeic acid-A was found to exhibit a potent inhibitory effect [IC50=0.4 µm].

Acylated sucroses and acylated quinic acids analogs from the flower buds of Prunus mume and their inhibitory effect on melanogenesis

The methanolic extract from the flower buds of Prunus mume, cultivated in Zhejiang Province, China, showed an inhibitory effect on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. From the methanolic extract, five acylated sucroses, mumeoses A-E, and three acylated quinic acid analogs, 5-O-(E)-p-coumaroylquinic acid ethyl ester, and mumeic acid-A and its methyl ester, were isolated together with 13 known compounds. The chemical structures of the compounds were elucidated on the basis of chemical and physicochemical evidence. Inhibitory effects of the isolated compounds on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells were also investigated. Acylated quinic acid analogs substantially inhibited melanogenesis. In particular, 5-O-(E)-feruloylquinic acid methyl ester exhibited a potent inhibitory effect [inhibition (%): 21.5±1.0 (P<0.01) at 0.1 μM]. Moreover, its biological effect was much stronger than that of the reference compound, arbutin [inhibition (%): 10.6±0.6 (P<0.01) at 10 μM]. Interestingly, the obtained acylated quinic acid analogs displaying melanogenesis inhibitory activity showed no cytotoxicity [cell viability >97% at 10 μM]. It is concluded that acylated quinic acid analogs are promising therapeutic agents for the treatment of skin disorders.

Structures of acylated sucroses and an acylated flavonol glycoside and inhibitory effects of constituents on aldose reductase from the flower buds of Prunus mume

Five new acylated sucroses, mumeoses K-O, and a new acylated flavonol glycoside, mumeflavonoside A, were isolated from the flower buds of Prunus mume, cultivated in Zhejiang province, China. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of the isolated acylated sucroses and flavonol glycosides on aldose reductase were also investigated. Several flavonol glycosides including mumeflavonoside A were shown to inhibit aldose reductase.

Acetylcholinesterase Inhibitory Activities of Flavonoids from the Leaves ofGinkgo bilobaagainst Brown Planthopper

Ginkgo bilobais a traditional Chinese medicinal plant which has potent insecticidal activity against brown planthopper. The MeOH extract was tested in the acetylcholinesterase (AChE) inhibitory assay with IC50values of 252.1 μg/mL. Two ginkgolides and thirteen flavonoids were isolated from the leaves ofGinkgo biloba. Their structures were established on the basis of spectroscopic data interpretation. It revealed that the 13 isolated flavonoids were found to inhibit AChE with IC50values ranging from 57.8 to 133.1 μg/mL in the inhibitory assay. AChE was inhibited dose dependently by all tested flavonoids, and compound6displayed the highest inhibitory effect against AChE with IC50values of 57.8 μg/mL.

Flavonoids from Halostachys caspica and their antimicrobial and antioxidant activities

Seven flavonoids have been isolated from the aerial parts of Halostachys caspica C. A. Mey. (Chenopodiaceae) for the first time. By means of physicochemical and spectrometric analysis, they were identified as luteolin (1), chrysin (2), chrysin 7-O-β-D-glucopyranoside (3), quercetin (4), quercetin 3-O-β-D-glucopyranoside (5), isorhamentin-3-O-β-D-glucopyranoside (6), and isorhamentin-3-O-β-D-rutinoside (7). All flavonoids were evaluated to show a broad antimicrobial spectrum of activity on microorganisms including seven bacterial and one fungal species as well as pronounced antioxidant activity. Among them, the aglycones with relatively low polarity had stronger bioactivity than their glycosides. The results suggested that the isolated flavonoids could be used for future development of antimicrobial and antioxidant agents, and also provided additional data for supporting the use of H. caspica as forage.

The selected flavonol glycoside derived from Sophorae Flos improves glucose uptake and inhibits adipocyte differentiation via activation AMPK in 3T3-L1 cells

Among nine flavonols (1-9) obtained from Sophorae Flos, we first isolated compounds 4, 5, 8, and 9. These isolates (1-9) were evaluated for the phosphorylation of AMPK and ACC. Administered at 10 μM, 9 possessed high potent activity. Compound 9 displayed a dose-dependent stimulation of glucose uptake in 3T3-L1 cells, and this increase was obviously attenuated by compound C, an AMPK inhibitor. In addition, 9 also phosphorylated AMPK and its downstream substrate ACC in 3T3-L1 cells in a time- and dose-dependent manner. Moreover, we discovered that compound C inhibits 9-stimulated ACC phosphorylation and motivated the 9-inhibited C/EBPα and PPARγ, and FAS gene expression, significantly. These results revealed the role of the AMPK downstream signaling pathway in 9-improved glucose metabolism in 3T3-L1 cells and 9-inhibited adipocyte differentiation. Differentiation was investigated by Oil Red O staining activity after 9 administration (0-20 μM) in 6 days. Compound 9 decreased mean droplet size in a dose-dependent manner. The results revealed that 9 blocked adipogenic conversion in 3T3-L1 cells together with several significant downregulating adipocyte-specific transcription factors, including PPARγ, C/EBPα, and SREBP1. It also reduced FAS gene expression in a dose-dependent manner, which is crucial for adipogenesis in vitro.

Acetylcholinesterase and Butyrylcholinesterase Inhibitory Compounds from Eschscholzia californica (Papaveraceae)

The roots and aerial parts of Eschscholzia californica Cham. (Papaveraceae) were extracted with ethanol. Repeated column chromatography, preparative TLC, and crystallization led to the isolation of fourteen isoquinoline alkaloids, the structures of which were determined on the basis of spectroscopic techniques and by comparison with literature values. One of the compounds isolated, 1-(3-hydroxy-4-methoxybenzyl)-2-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline (14), has not previously been isolated from a natural source. All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibition activity. None of the compounds isolated significantly inhibited both HuAChE and HuBuChE, but the two benzylisoquinoline alkaloids, reticuline 9 and 14, showed promising inhibitory activity against HuBuChE.

Phenolic glycosides from Kaempferia parviflora

Three phenolic glycosides were isolated together with two known flavonol glycosides from the H2O-soluble fraction of rhizomes of Kaempferia parviflora. Their structures were determined to be rel-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranoside] (1), its rel-5aS,10bR isomer (2), and (2R,3S,4S)-3-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranosyl]-3'-O-methyl-ent-epicatechin-(2alpha-->O-->3,4alpha-->4)-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside] (3). The structures were elucidated on the basis of analyses of chemical and spectroscopic evidence.

New megastigmane sesquiterpene and indole alkaloid glucosides from the aerial parts of Bupleurum chinense DC

A new megastigmane sesquiterpene glucoside named chaihuxinoside A (1), and a new indole diglucoside named chaihuxinoside B (9) were isolated from the aerial parts of Bupleurum chinense DC. along with eight known compounds. Structures of two new compounds were elucidated by a combination of chemical and spectroscopic methods. Chaihuxinosides A and B were characterized as 11-hydroxyl-4-en-3,9-dioxo- megastigmane-11-O-beta-D-glucopyranoside (1), and 3-carboxy-indole-10-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl ester (9), respectively.