DPPH radical-scavenging effect on some constituents from the aerial parts of <Emphasis Type="Italic">Lippia triphylla</Emphasis>

Lippia triphylla (L'Her) O. Kuntze (Verbenaceae; common name, Lemon Verbena) is used in Peru as a spice and herb tea for the prevention of arteriosclerosis. From the aerial parts of this plant, 25 known compounds—3 phenylpropanoid glucosides, 7 flavonoids, 5 phenylethanoid glycosides, 5 lignans, 2 sesquiterpenoids, and 3 triterpenoids—were isolated, and their chemical structures were elucidated on the basis of physical and spectral data. Among them, 19 aromatic compounds were examined for their scavenging effect on the stable free radical 1,1-diphenyl-2-picrylhydrazyl—4 phenylethanoid glycosides and 5 lignans indicated a potent scavenging effect. Of note, the EC₅₀ values of two phenylethanoid glycosides reached almost thrice that of α-tocopherol.     

Chromone and flavonol glycosides from <Emphasis Type="Italic">Delphinium hybridum</Emphasis> cv. “Belladonna Casablanca”

One new chromone and six known flavonol glycosides were isolated from the stems and leaves of Delphinium hybridum cv. “Belladonna Casablanca” (Ranunculaceae). The new chromone glycoside was elucidated as 2-methyl-chromone-5,7-diol 7-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (1). The six known flavonol glycosides were designated as compounds 2–5, being kaempferol-type glycosides, and compounds 6 and 7, being quercetin-type glycosides. The structures of these glycosides were determined by two-dimensional nuclear magnetic resonance (2D NMR) spectroscopic analysis and chemical evidence.     

Two new maltol glycosides and cyanogenic glycosides from <Emphasis Type="Italic">Elsholtzia rugulosa</Emphasis> Hemsl.

Two new maltol glycosides, maltol 6′-O-β-d-apiofuranosyl-β-d-glucopyranoside and maltol 6′-O-(5-O-p-coumaroyl)-β-d-apiofuranosyl-β-d-glucopyranoside, were isolated from Elsholtzia rugulosa Hemsl. along with 11 known compounds including prunasin and amygdalin. The structures were determined on the basis of spectroscopic and chemical evidence. This is the second example of isolation of cyanogenic glycosides from Lamiaceous plants.     

Two new glycosides from Viburnum plicatum Thunb. ex Murray var. plicatum f. plicatum

Two new glycosides, named plicatumoside A (1) and (+)-neomedioresinol 4,4′-di-O-β-d-glucopyranoside (2), together with 13 known compounds, were isolated from the leaves of Viburnum plicatum Thunb. ex Murray var. plicatum f. plicatum. Their structures were established on the basis of NMR, MS, and chemical data.     

New benzophenone and quercetin galloyl glycosides from <Emphasis Type="Italic">Psidium guajava</Emphasis> L.

New benzophenone and flavonol galloyl glycosides were isolated from an 80% MeOH extract of Psidium guajava L. (Myrtaceae) together with five known quercetin glycosides. The structures of the novel glycosides were elucidated to be 2,4,6-trihydroxybenzophenone 4-O-(6″-O-galloyl)-β-d-glucopyranoside (1, guavinoside A), 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6″-O-galloyl)-β-d-glucopyranoside (2, guavinoside B), and quercetin 3-O-(5″-O-galloyl)-α-l-arabinofuranoside (3, guavinoside C) by NMR, MS, UV, and IR spectroscopies. Isolated phenolic glycosides showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage-like cell line, RAW 264.7.     

Three new flavonoid glycosides from Oxytropis myriophylla

Three new flavonoids, myriophylloside I, II and III, were isolated from Oxytropis myriophylla (Leguminosae), together with four known flavonoid glycosides: isorhamnetin-3-O-β-d-glucoside, isorhamnetin-3-O-α-l-arabinosyl(1→6)-β-d-glucoside, quercetin and rutin. The structural elucidations of all the compounds were based on extensive spectroscopic methods, including HRESIMS and 2D-NMR experiments (HSQC, HMBC, ¹H–¹H COSY and HSQC-TOCSY), UV, IR and chemical evidence, together with comparison with reference values.     

Flavonol glycosides from the leaves of <Emphasis Type="Italic">Indigofera zollingeriana</Emphasis>

Two new flavonol glycosides were isolated from the 1-butanol (1-BuOH)-soluble fraction of a methanol (MeOH) extract of the leaves of Indigofera zollingeriana, along with four flavonol glycosides and three known megastigmane glucosides. The structures of the new compounds were elucidated by spectroscopic analyses as kaempferol 3-O-β-d-(2″-O-β-d-apiofuranosyl)glucopyranoside 7-O-α-l-rhamnopyranoside and 3-O-β-d-(2″-O-β-d-apiofuranosyl, 6″-O-α-l-rhamnopyranosyl)glucopyranoside 7-O-α-l-rhamnopyranoside.     

Two new neolignan glycosides from leaves of <Emphasis Type="Italic">Osmanthus heterophyllus</Emphasis>

Two new neolignan glycosides, (7R, 8R)-threo-guaiacylglycerol-8-O-4′-sinapyl ether 7-O-β-d-glucopyranoside (1) and (7S, 8R)-5-methoxydehydrodiconiferyl alcohol 4-O-β-d-glucopyranoside (2), and four known ones (3–6), were isolated from the leaves of Osmanthus heterophyllus. The structures of compounds 1–6 were established on the basis of spectral and chemical data.     

Aromatic monoterpenoid glycosides from the seeds of Paeonia ostii

Phytochemical investigation into the seeds of Paeonia ostii T. Hong et J. X. Zhang (Paeoniaceae) led to the identification of three new aromatic monoterpenoid glycosides, named paeostisides A–C (1–3), along with one known compound. Their structures were identified by spectroscopic analysis and chemical method.     

A new flavonol galloylrhamnoside and a new lignan glucoside from the leaves of <Emphasis Type="Italic">Koelreuteria henryi</Emphasis> Dummer

A new flavonol galloylrhamnoside, kaempferol 3-O-(2″,3″-di-O-galloyl)-α-l-rhamnopyranoside, and a new lignan glycoside, hinokinin 7-O-β-d-glucopyranoside were isolated from the leaves of Koelreuteria henryi, along with 18 known compounds, including six flavonol glycosides (3–8), three lignans (9–11), four chlorophyll derivatives (12–15), two steroids (16, 17), and three aromatic compounds (18–20). The structures were determined on the basis of spectral analysis and chemical evidence. The scavenging effect of 1–8 and 20 on the stable free radical 1,1-diphenyl-2-picrylhydrazyl was examined. Compounds 1, 5, 6, and 20 showed more potent activity than that of trolox.     

Flavonoid glycosides and limonoids from Citrus molasses

Molasses of tangerine orange (Citrus unshiu Markovich) is obtained as a waste product in the course of tangerine orange juice production. This molasses is expected to be a useful source of organic compounds such as flavonoids and limonoids. To elucidate a use for this molasses waste, we isolated and identified its organic constituents. Two new flavanonol glycosides were isolated from tangerine orange molasses, along with several flavonoids such as hesperidine, narirutin, eriodictyol, 3′,4′,5,6,7,8-hexamethoxy-3-O-β-d-glucopyranosyloxyflavone, and 3′,4′,5,6,7,8-hexamethoxy- 3-β-d-[4-O-(3-hydroxy-3-methylglutaloyl)]-glucopyranosyloxyflavone, and limonoids such as limonin, nomilin, and cyclic peptide, citrusin III. The structures of the new flavanonol glycosides were determined as (2R,3R)-7-O-(6-O-α-l-rahmnopyranosyl-β-d-glucopyranosyl)-aromadendrin and 7-O-(6-O-α- l-rahmnopyranosyl-β-d-glucopyranosyl)-3,3′,5,7-tetrahydroxy-4′-methoxyflavanone by means of spectral analyses using ¹H-NMR, ¹³C-NMR, and 2D-NMR. Of these compounds, flavanone glycoside, hesperidin and narirutin were isolated as the main constituents. Thus, molasses is a promising source of flavonoid glycosides.     

Two new acetylated flavonoid glycosides from Centaurium spicatum L

Two new acetylated flavonol glycosides, quercetin 3-O-[(2,4-diacetyl-α-l-rhamnopyranosyl)-(1→6)]-2,4-diacetyl-β-d-galactopyranoside (1) and quercetin 3-O-[(2,4-diacetyl-α-l-rhamnopyranosyl)-(1→6)]-3,4-diacetyl-β-d-galactopyranoside (2), in addition to two known acetylated quercetin glycosides quercetin 3-O-[(2,3,4-triacetyl-α-l-rhamnopyranosyl)-(1→6)-β-d-galactopyranoside (3) and quercetin 3-O-[(2,3,4-triacetyl-α-l-rhamnopyranosyl)-(1→6)-3-acetyl-β-d-galactopyranoside (4), were isolated from the aerial part of Centaurium spicatum (L.) Fritsch (Gentianaceae). Structure elucidation, especially the localization of the acetyl groups, and complete ¹H and ¹³C NMR assignments of these biologically active compounds were carried out using one- and two-dimensional NMR measurements, including ¹H- and ¹³C-NMR, DEPT-135, H–H COSY, HMQC and HMBC, in addition to HR-FAB/MS experiments.     

Five new glycosides from <Emphasis Type="Italic">Hypericum erectum</Emphasis> Thunb.

Five new glycosides, quercetin 3′-O-β-d-galactopyranoside (1), quercetin 3-O-(2″-acetyl)-β-d-glucopyranoside (2), 4,6-dihydroxy-2-methoxyphenyl 1-O-β-d-glucopyranoside (3), 4-hydroxy-2,6-dimethoxyphenyl 1-O-α-l-rhamnopyranosyl (1 → 6)-β-d-glucopyranoside (4) and 3-methyl-but-2-en-1-yl β-d-glucopyranosyl (1 → 6)-β-d-glucopyranoside (5), were isolated from Hypericum erectum Thunb. Their structures were established on the basis of spectral and chemical data.     

Constituents from leaves of Apocynum venetum L.

An analysis using HPLC–MS revealed that an extract from dried leaves of Apocynum venetum L. contained more than 15 kinds of phenolic constituents. Two malonated flavonol glycosides were further isolated, and their structures were determined to be quercetin 3-O-(6′′-O-malonyl)-β-d-glucoside (1) and quercetin 3-O-(6′′-O-malonyl)-β-d-galactoside (2) by NMR spectroscopic analysis. This is the first report describing the isolation of these malonated flavonol glycosides from A. venetum L. Both glycosides showed strong scavenging activity against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical.     

New isoflavone glycosides from <Emphasis Type="Italic">Iris spuria</Emphasis> L. (Calizona) cultivated in Egypt

Two new isoflavone glycosides, tectorigenin 7-O-β-d-glucopyranoside-4′-O-[β-d-glucopyranosyl-(1″″ → 6′′′)-β-d-glucopyranoside] (1) and iristectorigenin B 4′-O-[β-d-glucopyranosyl-(1′′′ → 6″)-β-d-glucopyranoside] (2), together with 11 known compounds, including six isoflavones, tectorigenin 7-O-β-d-glucopyranoside-4′-O-β-d-glucopyranoside (3), tectorigenin 4′-O-[β-d-glucopyranosyl-(1′′′ → 6″)-β-d-glucopyranoside] (4), tectorigenin 7-O-β-d-glucopyranoside (5), genistein 7-O-β-d-glucopyranoside (6), tectorigenin 4′-O-β-d-glucopyranoside (7), and tectorigenin (8); two phenolic acid glycosides, vanillic acid 4-O-β-d-glucopyranoside (9) and glucosyringic acid (10); a phenylpropanoid glycoside, E-coniferin (11); an auronol derivative, maesopsin 6-O-β-d-glucopyranoside (12); and a pyrrole derivative, 4-(2-formyl-5-hydroxymethylpyrrol-1-yl) butyric acid (13), were isolated from fresh Iris spuria (Calizona) rhizomes. The structures of these compounds were established on the basis of spectroscopic and chemical evidence. Inhibitory effects on the activation of Epstein–Barr virus early antigen were examined for compounds 1–8 and 12.     

Lignan glycosides from the leaves of <Emphasis Type="Italic">Osmanthus heterophyllus</Emphasis>

Seven known lignan glycosides were isolated from the leaves of Osmanthus heterophyllus: (+)-syringaresinol 4-O-β-d-glucopyranoside, (+)-syringaresinol 4, 4′-O-di-β-d-glucopyranoside, (+)-medioresinol 4, 4′-O-di-β-d-glucopyranoside, (+)-medioresinol 4-O-β-d-glucopyranoside, (+)-pinoresinol 4, 4′-O-β-d-glucopyranoside, (+)-epipinoresinol 4-O-β-d-glucopyranoside and phillyrin. Their structures were determined on the basis of spectral data.     

Prenylated flavonoid glucoside and two aliphatic alcohol glycosides from the leaves of Euodia meliaefolia (Hance) Benth.

A new prenylated flavonoid (1) and two new aliphatic glycosides (2, 3) have been isolated from leaves of Euodia meliaefolia (Hance) Benth., together with three known compounds, (2R,3R)-5,7,4′-trihydroxy-8-(3-methylbut-2-enyl)dihydroflavonol 7-O-β-d-glucopyranoside (phellamurin) (4), (2R,3R)-dihydroquercetin 3′-O-β-d-glucopyranoside (5), and (7R,8S)-dihydrodiconiferyl alcohol 4-O-β-d-glucopyranoside (6). Their structures were determined on the basis of the results of spectroscopic analysis.     

Novel phenolic glycosides,adenophorasides A–E,from Adenophora roots

Five novel phenolic glycosides, adenophorasides A (1), B (2), C (3), D (4), and E (5), were isolated from commercial Adenophora roots, together with vanilloloside (6), 3,4-dimethoxybenzyl alcohol 7-O-β-d-glucopyranoside (7), and lobetyolin (8). The structures of the new compounds (1–5) were characterized as 4-hydroxy-3-methoxyphenylacetonitrile 4-O-β-d-glucopyranoside (1), 4-hydroxy-3-methoxyphenylacetonitrile 4-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (2), 4-hydroxy-3-methoxyphenylacetonitrile 4-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (3), 4-hydroxyphenylacetonitrile 4-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (4), and 4-hydroxy-3-methoxybenzyl alcohol 4-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (5), respectively, by means of spectroscopic and chemical analyses.     

Glycosides from whole plants of Glechoma hederacea L.

From dried whole plants of Glechoma hederacea L. (Labiatae), seven known glycosides were isolated and identified: (6R,7E,9R)-megastigma-4,7-dien-3-one 9-O-β-d-glucopyranoside (1), apigenin 7-O-neohesperidoside (2), chrysoeriol 7-O-neohesperidoside (3), (+)-pinoresinol 4,4′-bis-O-β-d-glucopyranoside (4), (+)-syringaresinol 4,4′-bis-O-β-d-glucopyranoside (5), (+)-lariciresinol 4,4′-bis-O-β-d-glucopyranoside (6), and (7R,8R)-threo-7,9,9′-trihydroxy-3,3′-dimethoxy-8-O-4′-neolignan 4-O-β-d-glucopyranoside (7).     

Two new dimeric secoiridoid glycosides from the fruits of Ligustrum lucidum

Two new secoiridoid glycosides, ligusides A and B (1 and 2), as well as seven known compounds (3–9), were isolated from the fruits of Ligustrum lucidum. Their structures were elucidated on the basis of spectroscopic and chemical analysis.