Chemical constituents from the roots of Fallopia multiflora var. Ciliinerve

Phytochemical investigations on the roots of Fallopia multiflora var. Ciliinerve led to the isolation of eighteen compounds, including six chromones [2-methyl-5- carboxymethyl-7-hydroxychromone (1), 2-methyl-5-methylcarboxymethyl-7- hydroxychromone (2), 2,5-dimethyl-7-hydroxychromone (3), 2-methyl-5-hydroxymeth-yl-7-hydroxychromone (4), 2-methyl-5-carboxylicacid-7-hydroxy-chromone (5), and 2,5-dimethyl-7-hydroxychromone-7-O-β-D-glucopyranoside (6)], three lignans [Isolariciresinol (8), 5-[4-(3,4-dimethoxyphenyl)-2,3-dimethylbutyl]-1,3-benzodioxole (9), and isolariciresinol-9-O-β-D-xylopyranoside (10)], four anthraquinones [physcion-8-O-β-D-glucopyranoside (11), emodin-8-O-β-D-glucopyranoside (12), Rhein (13), and Chrysophanol (14)], three isobenzofurans [5,7-dihydroxy-isobenzofuran (15), 5-methoxy-7-hydroxy-isobenzofuran (16), and 5-methoxy-isobenzofuran-7-O-β-D-glucoside (17)], one phenolic acid [2,5-diacethylhy-droquinone (7)], and one pyran [Zanthopyranone (18)]. Among them, compounds 1, 3, 6, 13 and 14 were reported from F. multiflora var. Ciliinerve for the first time, compounds 2, 8, 10 and 15–17 were isolated from the genus Fallopia for the first time, and compounds 4, 9 and 18 were isolated for the first time from Polygonaceae family. Furthermore, the isolation of compounds 5 and 7 were reported for the first time in plants. Their structures were identified by spectroscopic methods and compared with those previously published. The chemotaxonomic significance of these isolated compounds has also been discussed.     

Chemical constituents from the rhizome of Anemone hupehensis

A phytochemical investigation on the rhizome of Anemone hupehensis resulted in the isolation of thirteen compounds, including six neolignan glycosides (1-6), two phenylpropanoid glycosides (7, 8), a phenolic glycoside (9) and four triterpenoid saponins (10-13). The structures of the isolated compounds were elucidated on the basis of spectroscopic data. This is the first report of neolignan glycoside, phenylpropanoid glycoside, and phenolic glycoside from genus Anemone. This is also the first study to report compounds 1-5 and 7-9 from family Ranunculaceae. All the compounds, except 10 were isolated from A. hupehensis for the first time. The chemotaxonomic significance of the isolated compounds was discussed.     

New heterocyclic compounds from Ranunculus ternatus Thunb.

Five new heterocyclic compounds, 5-α-d-fructofuranosylmethyl-furfural (1), 5-β-d-fructofuranosylmethyl-furfural (2), 5-β-d-fructopyranosylmethyl-furfural (3), 4-(2-((2S-2,3-dihydroxypropoxy)methyl)-5-formyl-1H-pyrrol-1-yl)butanoic acid (4), and 3S,4S-4,5,8-trihydroxy-3-(prop-1-en-2-yl)isochroman-1-one (5), were obtained from the root of Ranunculus ternatus Thunb., which is a traditional Chinese anti-tuberculosis medicine. Their structures were elucidated by UV, IR, HRESIMS, NMR data, and the comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Notably, compounds 1–3 are rarely occurring furfural fructosides in natural sources. These heterocyclic compounds could be further studied for the synthetic chemists and pharmacologists due to the source and structural properties.     

A new bicyclic sesquiterpenoid from Merremia yunnanensis

A new sesquiterpenoid, 1α,4β,8β,9β-eudesmane-tetrol-1-O-β-D-glucopyranoside (1), together with nine known compounds (2–10), were isolated from Merremia yunnanensis. The structures of these compounds were elucidated by spectroscopic methods and compared to data in the literature. All these compounds (1–10) were firstly isolated from this plant, and compounds 3, 5, 7, and 10 were reported from the Merremia genus for the first time. The significance of the chemotaxonomy for these compounds is described herein.     

Antidiabetic triterpenoids from the leaves of Paeonia suffruticosa and Paeonia delavayi

Three new nor-oleanane triterpenoids, paeonenoides I-K (1-3), together with 13 known triterpenoids including nor-oleanane, oleanane, ursane, and cycloartane types, were isolated from the leaves of Paeonia suffruticosa and P. delavayi. The structures of the new compounds were elucidated with the aid of HRESIMS, 1D and 2D NMR, IR, and [α]_D spectroscopic methods. Nine compounds (5-6, 8-11, 13-14 and 16) showed inhibition against PTP1B with IC₅₀ values ranging from 36.5 to 192.6 μM, six compounds (5-6, 8-10 and 14) exhibited inhibitory activity against GPa with IC₅₀ values ranging from 39.8 to 108.0 μM, and five compounds (1, 6, 10, 15 and 16) could significantly stimulate GLP-1 secretion by 100.2–313.4% (20 μM). Docking study demonstrated that compounds 5 and 6 strongly bonded with Gpa and PTP1B by salt bridges, hydrogen bonds and hydrophobic interactions, verifying the importance of carboxyl and hydroxyl groups. Especially, compounds 5 and 14 could simultaneously inhibit PTP1B and GPa with IC₅₀ values of 57.8, 47.9 μM and 39.8, 45.2 μM, and compounds 6 and 10 could stimulate GLP-1 secretion by 293.6% and 313.4% at 20 μM.     

Bioactive constituents from the leaves of Croton tiglium

Fifteen compounds, including five new phorbol esters (1-5) and ten known metabolites were isolated from the leaves of Croton tiglium. The structures of new compounds 1-5 were determined by comprehensive analysis of the HRESIMS, IR, 1D and 2D NMR spectral data. The isolates were assayed for their larvicidal and α-glucosidase inhibitory activity; results suggested the new compounds 1-4 possessed significant insecticidal activity, inhibiting the Plutella xylostella with LC₅₀ values ranging from 0.081 to 0.114 μg/mL, while the sesquiterpenoids 11 and 15 showed noticeable α-glucosidase inhibitory activity with IC₅₀ values of 11.27 and 8.13 μM, respectively.     

Flavonoid glycosides from the aerial parts of Curcuma comosa

Four new flavonoid glycosides, curcucomosides A–D (1–4), three known flavonoid glycosides, 5–7, and four known diarylheptanoids, 8–11, were isolated from the ethanol extract of the aerial parts of Curcuma comosa. The structures of the new compounds were established as rhamnazin 3-O-α-l-arabinopyranoside (1), rhamnocitrin 3-O-α-l-arabinopyranoside (2), rhamnazin 3-O-α-l-rhamnopyranosyl-(1→2)-O-α-l-arabinopyranoside (3), and rhamnocitrin 3-O-α-l-rhamnopyranosyl-(1→2)-O-α-l-arabinopyranoside (4) by spectroscopic analysis and chemical reactions whereas those of the known compounds were identified by spectral comparison with those of the reported values.     

Chromone acyl glucosides and an ayanin glucoside from Dasiphora parvifolia

Two new chromone acyl glucosides, 5-hydroxy-7-O-(6-O-p-cis-coumaroyl-β-D-glucopyranosyl)-chromone (1) and 5-hydroxy-7-O-(6-O-p-trans-coumaroyl-β-D-glucopyranosyl)-chromone (2), and a new flavonoid glucoside, ayanin 3′-O-β-D-glucopyranoside (3) were isolated from aerial parts of Dasiphora parvifolia, together with flavonoid glycosides (4–10), catechins (11, 12), and hydrolysable tannins (13, 14). The chemical structures of these compounds were elucidated on the basis of spectroscopic data. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and the hyaluronidase inhibitory activity of these compounds were evaluated.     

Chemical constituents of the roots of Eupatorium chinense and their anti-inflammatory activities

In this study, three new compounds (1-3), together with fifteen known ones (4-18) were isolated from a petroleum ether extract of the roots of Eupatorium chinense. The structures of new compounds were elucidated by 1D, 2D nuclear magnetic resonance (NMR), circular dichroism spectrum (CD), mass spectrum (MS) along with other spectroscopy methods. In addition, twelve compounds were evaluated in vitro for their anti-inflammatory activities, while compounds 3 and 5 exhibited moderate activities with inhibition rates of 23.08 % and 25.19 %, respectively.     

Chemical constituents from the aerial parts of Impatiens hypophylla Makino var. hypophylla

Seven flavonoids such as luteolin (1), luteolin 7-O-β-glucopyranoside (2), luteolin 3'-O-β-glucopyranoside (3), chryseriol (4), apigenin (5), apigenin 7-O-β-glucopyranoside (6) and astragalin (7) and one coumarin, scopoletin (8) were isolated from the aerial parts of Impatiens hypophylla Makino var. hypophylla (Family: Balsaminaceae). Structures of these compounds were elucidated on the basis of spectroscopic methods. All these compounds were isolated for the first time from I. hypophylla var. hypophylla.     

Flavonoids and phenolic acids from the aerial parts of Alyssum alyssoides L. (Brassicaceae)

Two phenolic acids (1 and 2) and seven flavonoids (3–9) were isolated from the aerial parts of Alyssum alyssoides (Brassicaceae). All these compounds (1–9) were isolated from this particular species for the first time. Their structures were identified, on the basis of MS and NMR spectra as: p-hydroxy-benzoic acid (1), 3-methoxy-4-hydroxybenzoic acid (vanillic acid) (2), kaempferol 3-O-β-D-glucopyranoside (astragalin) (3), kaempferol 3-O-(6″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (nicotiflorin) (4), quercetin 3-O-β-D-glucopyranoside (isoquercetin) (5), quercetin 3-O-β-D-galactopyranoside (hyperoside) (6), isorhamnetin 3-O-β-D-glucopyranoside (7), isorhamnetin 3-O-β-D-galactopyranoside (8) and isorhamnetin 3-O-(6″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (narcissin) (9). The chemotaxonomic significance of these compounds was summarized.     

Flavonoid glycosides from the leaves of Aphananthe aspera (Thunb.) Planch. (Cannabaceae) and their chemotaxonomic significance

From the leaves of Aphananthe aspera (Thunb.) Planch. (Family: Cannabaceae), six flavonol glycosides, such as quercetin 3-O-β-glucopyranoside (1), kaempferol 3-O-β-glucopyranoside (2), quercetin 3-O-rutinoside (3), kaempferol 3-O-rutinoside (4), quercetin 3-O-neohesperidoside (5) and kaempferol 3-O-neohesperidoside (6) were isolated and identified. Structure elucidation of these compounds was performed on the basis of NMR spectral data. All these compounds were isolated for the first time from the genus Aphananthe. Chemotaxonomic significance and distribution of these flavonoid derivatives among the genera of Cannabaceae are explained in detail.     

New C-2 diastereomers of flavanone glycosides conjugated with 3-hydroxy-3-methylglutaric acid from the pericarp of Citrus grandis (L.) Osbeck

Two new 3-hydroxy-3-methylglutaryl (HMG) flavanone 7-O-diglycosides, cigranosides A and B (1 and 2), the known naringenin 7-(2′′-α-rhamnosyl-6′′-(3′′′′-hydroxy-3′′′′-methylglutaryl)-glucoside (melitidin, 3), their common biosynthetic precursor flavanone 7-O-diglycoside (naringin, 4), and one known flavone 7-O-diglycoside (rhoifolin, 5) were isolated from the pericarp of Citrus grandis (L.) Osbeck. The structures of these compounds were elucidated by spectroscopic and chemical techniques. The relative ratios and absolute configurations of the C-2 diastereomers of compounds 1, 2 and 4 were determined by online normal-phase HPLC-CD using a Chiralcel column. The absolute configuration of the HMG fragment in compounds 1–3 was assigned to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. The NO inhibitory activities of compounds 1–5 were evaluated using lipopolysaccharide-induced RAW264.7 cells. Compounds 1–5 were not cytotoxic to RAW264.7 cells at 10 μM.     

Stilbene glucosides from the bulbs of Iris tingitana

Two new dimeric stilbene glucosides, tingitanol A (1) and tingitanol B (2) together with trans-resveratrol 3-O-glucopyranoside (3) in addition to three known isoflavones, 5-O-methylgenistein (4), 5-O-methylgenistein 7-O-β-d-glucopyranoside (5) and betavulgarin (6) have been isolated for the first time from the fresh bulbs of Iris tingitana Boiss. & Reut. Their structures were established on the basis of the spectral data and direct comparison with values from previously identified analogues. Additionally, the isolated compounds (1–6) were evaluated for the free radical scavenging activity.     

Cinnamate derivatives of fructo-oligosaccharides from Lindelofia stylosa

Phytochemical investigation on the whole plants of Lindelofia stylosa (Kar. and Kir.) has led to the isolation of eight fructo-oligosaccharide cinnamate esters 1-8. Six new compounds 1, 2, and 5-8 were isolated from the butanol extract of the plant. Compounds 1-4 belong to sucrose derivatives, while compounds 5-6 and 7-8 belong to 1-kestose- and nystose-type oligosaccharides, respectively. The fructo-oligosaccharides have been obtained from L. stylosa for the first time.     

C-glycosylflavone with rotational isomers from Vaccaria hispanica (Miller) Rauschert seeds

Five C-glycosylflavone were isolated from Vaccaria hispanica (Miller) Rauschert seeds. Their NMR spectra showed separate signals because of the existence of rotational isomers, which is an unusual phenomenon. The spectroscopic data revealed that compounds 1–5 were identified as apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-β-d-glucopyranoside (1), apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-(6′′′′-O-dihydroferuloyl)-β-d-glucopyranoside (2), apigenin 6-C-β-d-glucopyranosyl-7-O-(6′′′-O-dihydroferuloyl)-β-d-glucopyranoside (3) and isovitexin-2′′-O-arabinoside (4) and saponarin (5), respectively. The structure of ‘vaccarin’ was revised to apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-β-d-glucopyranoside and consequently 1 should be named ‘vaccarin’. Among the isolated compounds, 2 and 3 are new and named vaccarin E and vaccarin F, respectively.     

An aromatic amide C-glycoside and a cyclitol derivative from stem barks of Piper guineense Schum and Thonn (Piperaceae)

Two new compounds, an aromatic amide C-glycoside, 4-C-β-D-glucopyranosyl-3,5-dihydroxy-2-methoxybenzamide (1) and a cyclitol derivative, 4-O-caffeoyl-2-C-methoxycarbonyl-1-C-methyl-2,3,6-trihydroxycyclohexanecarboxylic acid (2), were isolated from the methanol soluble extract of the stem barks of Piper guineense Schum and Thonn, together with four known quinic acids derivatives including 3-O-caffeoyl-1-methylquinic acid (3), 3-O-feruloylquinic acid (4), ethyl-4-O-feruloylquinate (5), and 5-caffeoylquinic acid (6). Their structures were established on the basis of detailed spectroscopic analysis. The radical scavenging activity of the isolates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. Five of them were found to have significant radical scavenging activities, while compounds 2 and 3 displayed the highest activities with IC₅₀ values of 8.35 and 7.06 μM, respectively.     

Synthesis and biological evaluation of pyrano[4,3-b][1]benzopyranone derivatives as monoamine oxidase and cholinesterase inhibitors

A series of eighteen pyrano[4,3-b][1]benzopyranone derivatives (1a-9b) were synthesized, and structure-activity relationships of their monoamine oxidase (MAO) A and B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitory activities were evaluated. Most of the synthesized compounds exhibited weak inhibitory activity toward MAO-A, whereas compounds 2a, 2b, 4a, 4b, 5a, 5b, 6a, 6b, 8a and 8b showed potent inhibitory activities toward MAO-B. Intriguingly, compounds 5a, 5b, and 8a showed inhibitory activities comparable to pargylin, used as a positive control for MAO-B. Substitution of butoxy at the C3 position or of chlorine at the C8 position of pyrano[4,3-b][1]benzopyranone increased the inhibitory activity of the compound toward MAO-B. The results of a molecular docking study supported this structural effect. Most of the compounds exhibited no or slight inhibitory activity toward AChE and BChE, with exo type compounds bearing a butoxy group, such as compounds 2b, 5b and 8b, showing weak but distinct inhibitory activities toward BChE. This report is the first to identify pyrano[4,3-b][1]benzopyranone derivatives as potent and selective MAO-B inhibitors. 3-Butoxy-8-chloro-pyrano[4,3-b][1]benzopyranone (5b) may be useful as a lead compound for the development of MAO-B inhibitors.     

A pair of new lignan enantiomers from Croton tiglium

A pair of new 3′,7-epoxy-8,4′-oxyneolignan enantiomers [(+)-1 and (−)-1] as well as a known phenylpropanoid (2) were isolated from the seeds of Croton tiglium Linn. Their structures were established based on extensive spectroscopic analyses. The absolute configurations of (+)-1 and (−)-1 were determined by NMR data calculations and electronic circular dichroism calculations. All compounds were isolated from the genus Croton for the first time. Particularly, (+)-1 and (−)-1 were the first 3′,7-epoxy-8,4′-oxyneolignanes reported in Croton. The chemotaxonomic significance of these compounds was discussed.     

Naphthofuran precursors of sesquiterpenoid aldehydes in diseased Gossypium

Crude terpenoid fractions from stele tissues of Gossypium barbadense infected with Verticillium dahliae contained two prominent compounds that were nonaldehydic, but readily autooxidized to the terpenoid aldehydes hemigossypol and 6-methoxyhemigossypol. Spectral analyses, chemical studies, and comparisons with model compounds showed that these compounds were the sesquiterpenoids 3,4-dihydroxy-5-isopropy]-7-methy]-2H-naphtho[1,8-bc]furan (1a) and 3-hydroxy-5-isopropyl-4-methoxy-7-methyl-2H-naphtho[1,8-bc]furan (1b). The trivial names desoxyhemigossypol and desoxy-6-methoxyhemigossypol are proposed for (1a) and (1b). The sesquiterpenoid, previously isolated and named vergosin, is apparently desoxy-6-methoxyhemigossypol.