Flavonoid glycosides and the chemosystematics of Eucalyptus camaldulensisis

Leaf flavonoid glycosides of Eucalyptus camaldulensis were identified as kaempferol 3-glucoside and 3-glucuronide; quercetin 3-glucoside, 3-glucuronide, 3-rhamnoside, 3-rutinoside and 7-glucoside, apigenin 7-glucuronide and luteolin 7-glucoside and 7-glucuronide. Two chemical races were observed based on the flavonoid glycosides. These races correspond to the northern and southern populations of species growing in Australia. The Middle Eastern species examined were found to belong to the southern Australian chemical race. The major glycosides of E. occidentalis proved to be quercetin and myricetin 3-glucuronide.     

Three new flavonoid glycosides from the aerial parts of Graptophyllum grandulosum Turril (Acanthaceae)

Grandulosides A-C, three new flavonoid glycosides, were isolated from the aerial parts of Graptophyllum grandulosum Turill and identified as chrysoeriol-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (1), chrysoeriol-7-O-[4′′′-O-acetyl-β-d-apiofuranosyl-(1 → 2)]-β-d-xylopyranoside (2) and 7-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-(4′′-Sodium hydrogeno sulfate) glucopyranoside (3). Four known compounds, chrysoeriol-7-O-β-d-xyloside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (5), luteolin-7-O-β-d-apiofuranosyl-(1 → 2)-β-d-xylopyranoside (6) and sucrose (7) were also obtained. The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D-NMR (¹H, ¹³C) and 2D-NMR (COSY, NOESY, HSQC and HMBC) and by comparison with the literature data.     

Spirostanol glycosides from Asparagus plumosus

Three spirostanol glycosides were isolated from a methanol extract of the leaves of Asparagus plumosus and characterized.     

Twelve pregnane glycosides from Cynanchum atratum

Eleven new 14,15-seco-pregnane-type steroidal glycosides, cynanosides P₁-P₅, Q₁-Q₃, R₁-R₃, and a novel 12,13-seco-14,18-nor-pregnane-type steroidal glycoside, cynanoside S, were isolated from the roots of Cynanchum atratum, together with four known compounds, atratoside C, sublanceoside E₃, chekiangensoside C and cynatroside B. Their structures were determined on the basis of spectroscopic analysis and chemical evidence.     

Two acylated flavanone glycosides from Nierembergia hippomanica

Two new acylated flavanone glycosides have been isolated from Nierembergia hippomanica and identified by spectral data as pinocembrin 7-O-β-(3?-O-acetyl)neohesperidoside and pinocembrin 7-O-β-(6″-O-acetyl)neohesperidoside.     

Iridoid glycosides from Galium verum

From the aerial parts of Galium verum in flower, asperuloside and V₁ iridoid were isolated. From the mother liquor obtained on recrystallizatio     

Sesquiterpene lactone glycosides from Crepis capillaris

Four new sesquiterpene lactone glucosides, in addition to known compounds, have been isolated from the roots of Crepis capillaris and their structures elucidated on the basis of spectral analysis and hydrolytic studies.     

Acylated flavonoid and phenylethanoid glycosides from Marrubium velutinum

From the aerial parts of Marrubium velutinum, one acylated flavonoid glycoside, chrysoeriol 7-O-(3",6"-di-O-E-p-coumaroyl)-beta-D-glucopyranoside, and two tetrasaccharidic phenylethanoid glycosides, velutinosides I-II, have been isolated together with ten known flavonoids and seven known phenylethanoid glycosides. The structures of the isolated compounds were established by means of NMR, MS, and UV spectral analyses.     

Three acylated flavone glycosides from Sideritis ozturkii Aytac & Aksoy

From the aerial parts of Sideritis ozturkii, three new flavonoids, chrysoeriol 7-O-[2'-O-caffeoyl-O-acetyl-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside], chrysoeriol 7-O[2'-O-caffeoyl-beta-D-glucopyranosyl-(1 -->2)-beta-D-glucopyranoside] and chrysoeriol 7-O[2'-O-p-coumaroyl-6'-beta-O-acetyl-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside] named as ozturkosides A, B and C, respectively, were isolated, along with three known phenylethanoid glycosides, verbascoside, leucoseptoside A, martynoside and five known diterpenoids, 7-epicandicandiol, linearol, sidol, sideroxol, epoxyisolinearol. The structures were elucidated mainly by spectroscopic methods.     

Flavonol glycosides from Securidaca diversifolia

Twelve flavonol glycosides have been isolated from the leaves of Securidaca diversifolia. The separation of ten quercetin 3-glycosides and two kaempferol 3-glycosides was achieved by droplet counter-current chromatography (DCCC), preparative reversed-phase chromatography and gel chromatography. The structures were established on the basis of partial and total acid hydrolysis and spectral data (UV, ¹³C NMR, FAB, MS, D/CI MS). The four apiosides: quercetin 3-(2″-β-D-apiofuranosyl-β-D-glucopyranoside), 3-(2″-β-D-apiofuranosyl-β-D-galactoside), 3-(2″-β-D-apiofuranosyl-α-L-arabinopyranoside) and 3-(2″-β-D-apiofuranosyl-β-D-xylopyranoside) are new natural products. The structure of kaempferol 3-(2″-β-D-apiofuranosyl-β-D-glucopyranoside), previously isolated from Cicer arietinum, is confirmed.     

Trihydroxy-C18-acids and a labdane from rudbeckia fulgida

Extraction of Rudbeckia fulgida furnished 13αH-labd-8(17)-en-15-al-19-oic acid, two new C₁₈-acids tentatively formulated as 9 (S*),12 (S*),13 (S*)-trihydroxyoctadeca-10(E),15 (Z)-dienoic acid and 9 (S*),12 (S*),13 (S*)-trihydroxyoctadec-10 (E)-enoic acid, several known C₁₄-polyacetylenes and several flavone glycosides.     

Furostanol glycosides from Trigonella foenum-graecum seeds

Two new furostanol glycosides trigofoenosides A and D have been isolated from the Trigonella foenum-graecum seeds as their methyl ethers, A-1 and D-1. Their structures have been determined as (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (A-1) and (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-[β-D-glucopyranosyl (1 → 3)]-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (D-1).     

Melanogenesis inhibitory pregnane glycosides from Cynanchum atratum

Bioassay-guided fractionation of the methanolic extract from the roots of Cynanchum atratum has resulted in the isolation of three new pregnane glycosides (1–3) along with four known compounds (4–7). Their structures were identified by analysis of the spectroscopic data including extensive 2D NMR. All of the isolates were evaluated for their potential to inhibit the melanin production in α-melanocyte stimulating hormone (α-MSH)-activated B16 melanoma cells. Of these, compounds 4–7 dose-dependently inhibited the melanin production with the IC₅₀ values ranging from 4?μM to 33?μM.     

An acylated allose-containing 8-hydroxyflavone glycoside from Veronica filiformis

A novel flavone glycoside has been obtained from the whole plant of Veronica filiformis and identified by means of ¹³C NMR spectroscopy as isoscutellarein 4′-methyl ether 7-O-β-(6?-O-acetyl-2″-O-allosylglucoside). The related isoscutellarein glycoside is also present. This is the first report of 2-allosylglucose as a disaccharide unit of flavonoids. ¹³`C NMR data on some A-ring trioxygenated flavonoids are also presented.     

A comparative study of the flavonoids of Medicago radiata with other Medicago and related Trigonella species

The flavonoid glycosides of Medicago radiata as well as M. arabica, M. polymorpha, M. sativa, Trigonella coerulescens, T. foenum-graecum and T. spicata were studied in detail. Major glycosides identified were the 7-glucuronides of apigenin, luteolin, chrysoeriol and tricin, as well as lesser amounts of di- and triglucuronides of chrysoeriol and tricin. Also identified were the 3-robinobioside and 3,7-diglucoside of kaempferol, along with lesser amounts of quercetin-3,7-diglucoside, 4′,7-dihydroxyflavone, 3′,4′,7-trihydroxyflavone, formononetin and daidzein. Twelve other Medicago and Trigonella species were also studied for their flavonoid aglycones. The systematic position of M. radiata is discussed.     

Bitter phenylpropanoid glycosides from Conandron ramoidioides

A new bitter glycoside, conandroside and a known glycoside, acteoside were isolated from Conandron ramoidioides. On the basis of the chemical and spectral evidence, conandroside was shown to be 2-(3′,4′-dihydroxy-phenyl)-ethanol 1-O-β-D-xylosyl-(1 → 3)-β-D-(4-caffeyl)-glucoside.     

Three iridoid glycosides from Viburnum furcatum

Three new bitter iridoid glycosides having an 8,10,11-oxygen substituted iridoid skeleton with an isovaleryl moiety at C-1, have been isolated from the ether and ethyl acetate soluble fractions of the leaves of Viburnum furcatum. Two of them had a glucose moiety at C-11 of the iridoid skeleton and a p-coumaroyl group linked to C-6 of the sugar, and they were found to be geometrical isomers about the double bond of the p-coumaroyl2 moiety. The third one was characterized as a alloside of the same aglycone.