C-glycosylanthocyanidins synthesized from C-glycosylflavones

Nine C-glycosyldeoxyanthocyanidins, 6-C-β-glucopyranosyl-7-O-methylapigeninidin, 6-C-β-glucopyranosyl-7-O-methylluteolinidin, 6-C-β-(2″-O-β-glucopyranosylglucopyranosyl)-7-O-methylapigeninidin, 6-C-β-(2″-O-β-glucopyranosylglucopyranosyl)-7,4′-di-O-methylapigeninidin, 8-C-β-glucopyranosylapigeninidin, 8-C-β-(2″-O-α-rhamnopyranosylglucopyranosyl)apigeninidin, 8-C-β-(2″-O-α-(4″′-O-acetylrhamnopyranosyl)glucopyranosyl)apigeninidin, 6,8-di-C-β-glucopyranosylapigeninidin (8), 6,8-di-C-β-glucopyranosyl-4′-O-methylluteolinidin (9), have been synthesized from their respective C-glycosylflavones (yields between 14% and 32%) by the Clemmensen reduction reaction using zinc-amalgam. The various precursors (C-glycosylflavones) of the C-glycosylanthocyanidins were isolated from either flowers of Iris sibirica L., leaves of Hawthorn ‘Crataegi Folium Cum Flore’, or lemons and oranges. This is the first time C-glycosylanthocyanidins have been synthesized. The structures of all flavonoids including the flavone rotamers were elucidated by 2D NMR techniques and high-resolution electrospray MS. The distribution of the various structural forms of 8 and 9 are different at pH 1.1, 4.5, and 7.0, however, the two pigments undergoes similar structural transformations at the various pH values. Pigments 8 and 9 with C-C linkages between the sugar moieties and the aglycone, were found to be far more stable towards acid hydrolysis than pelargonidin 3-O-glucoside, which has the typical anthocyanidin C-O linkage between the sugar and aglycone. This stability may extend the present use of anthocyanins as nutraceuticals, pharmaceuticals or colorants.     

Flavonoids in the species of Cyrtomium (Dryopteridaceae) and related genera

Flavonoids in 19 Cyrtomium, three Cyrtogonellum and two Phanerophlebia taxa were surveyed. Major flavonoids were flavonol O-glycosides based on kaempferol, quercetin, and sometimes myricetin, and C-glycosylflavones, such as isovitexin, vitexin, isoorientin, orientin and their O-glycosides. The C-methylflavanones, farrerol and cyrtominetin, and their 7-O-glucosides were isolated from Cyrtomium devexiscapulae and Cyrtomium laetevirens. Flavanones have been reported from Cyrtomium falcatum sensu lato. Though C. falcatum sensu lato is divided into four taxa, i.e. C. falcatum subsp. falcatum, C. falcatum subsp. australe, C. falcatum subsp. littorale, and C. devexiscapulae, the occurrence of the flavanones was restricted to C. devexiscapulae, and they did not occur in C. falcatum sensu stricto.     

Leaf press juice from Bryophyllum pinnatum (Lamarck) Oken induces myometrial relaxation

Aims

The use of preparations from Bryophyllum pinnatum (Lamarck) Oken (Kalanchoe pinnata (Lamarck) Persoon) in tocolysis is supported by clinical evidence. We studied here the effect of B. pinnatum leaf press juice and its chemical fractions on the response of human myometrial strips. No data are available if the influence on myometrial strips of the juice differs from that of its components in the chemical fractions, in order to increase the pharmacological effect.

Methodology

In vitro study to test the effect of repeated addition of B. pinnatum leaf press juice (BPJ) and its chemical components in several dilutions (undiluted, 1-10%) on myometrium strips hang up in a myograph chamber. Chemical analysis is including HPLC, MPLC with Sephadex LH-20 and TLC.

Results

All test solutions are inhibiting contractility by reducing the amplitude and the area under the curve (AUC) of the contractions. Undiluted BPJ and its undiluted chemical fraction 4 are reducing most effective these two parameters: the amplitude was at 78% of the baseline (95% CI (77-89); p < 0.05) at the second addition of the BPJ and at 70% (95% CI (50-90); p < 0.05) of the first addition of fraction 4; the AUC was at 82% (95% CI (69-95); p < 0.05) of the baseline at the first addition of the press juice and at 51% (95% CI (27-74); p < 0.05) at the first addition of fraction 4. The BPJ decreased amplitude and AUC significantly faster and increased frequency significantly faster than the control. Fractions could be tentatively assigned to bufadienolids, flavonoids and cinnamic acids. Fraction 4, accounted for flavonoids, increased the frequency of the contractions most effectively: 557% of the baseline (95% CI (316-797); p < 0.05) at the first addition.

Conclusion

Leaf juice of B. pinnatum and its flavonoid fraction are most effective in relaxing myometrial strips by inducing frequency.     

C-glycosylflavones from Oryza sativa

Eight flavone C-glycosides isolated from rice plant were found to act as probing stimulants for planthoppers. They have been identified as the known compounds schaftoside, neoschaftoside, carlinoside, isoorientin 2″-glucoside and the new constituents neocarlinoside (6-C-β-D-glucopyranosyl-8-C-β-L-arabinopyranosylluteolin), isoscoparin 2″-glucoside (chrysoeriol 6-C-β-D-(2-O-β-D-glucopyranosyl)glucopyranoside) and its 6?-p-coumaric and ferulic acid esters.     

Flavonoid profiles in the Heliohebe group of New Zealand Veronica (Plantaginaceae)

The Heliohebe group of Veronica (sect. Hebe) consists of five species occurring in the South Island of New Zealand. These species and a hybrid were analysed for their flavonoids. Five flavone glycosides were isolated and identified by NMR spectroscopy and three additional glycosides were detected by LC–UV–MS. Luteolin 7-O-, 3′-O- and 4′-O-glucosides and apigenin 7-O-glucoside were present in all six taxa investigated, 6-hydroxyluteolin glycosides were found in five and a luteolin caffeoylglycoside in four taxa, while a hypolaetin 7-O-glycoside was detected only in Veronica pentasepala. The 3′-O- and 4′-O-glucosides of luteolin are also common in other species of Veronica sect. Hebe (restricted to the Southern Hemisphere), but are rare in Northern Hemisphere species of Veronica and thus act as good chemotaxonomic markers for the section. The relatively simple flavonoid profiles found in the Heliohebe group are plesiomorphic and consistent with the group's status as sister to the Hebe clade. Based on the detected flavonoids, two groups could be distinguished within the Heliohebe clade: (1) Veronica hulkeana, Veronica lavaudiana and Veronica raoulii, characterised by luteolin caffeoylglycoside, and (2) V. pentasepala and Veronica scrupea, where this compound is replaced by a 6-hydroxyluteolin dihexoside.     

New C-glycosylflavones from Mollugo distica

Four C-glycosylflavones isolated from Mollugo distica were identified as 8-C-β-d-glucopyranosyl-genkwanin, 8-C-α-l-arabinopyranosylgenkwanin and their 2″-rhamnosides.     

New C-glycosylflavones from Cerastium arvense

Three C-glycosylflavones isolated from Cerastium arvense have been identified as 6-C-xylosyl-apigenin (cerarvensin), its 7-O-glucoside and isovitexin 7,2″-di-O-glucoside.     

Leaf essential oil composition of 10 species of Ocotea (Lauraceae) from Monteverde,Costa Rica

The leaf essential oils of 10 species of Ocotea (Lauraceae) from Monteverde, Costa Rica (Ocotea floribunda, Ocotea holdridgeana, Ocotea meziana, Ocotea sinuata, Ocotea tonduzii, Ocotea valeriana, Ocotea veraguensis, Ocotea whitei, and two undescribed species, Ocotea new species “los llanos”, and Ocotea new species “small leaf”) have been obtained by hydrodistillation and analyzed by GC–MS in order to discern the differences and similarities between the volatile chemical compositions of these species. The principal common constituents of the 10 species of Ocotea were α-pinene, β-pinene, β-caryophyllene, and germacrene-D.     

Isolation of anti-Candida albicans compounds from Markhamia obtusifolia (Baker) Sprague (Bignoniaceae)

An increase in clinical cases of Candidiosis globally as well as fungal resistance to drugs prompted the search for novel anti-Candida albicans agents from plant sources. Leaf extracts of Markhamia obtusifolia were screened for activity against C. albicans in vitro. An acetone extract obtained following serial exhaustive extraction contained mainly the active components with at least four active zones on the bioautogram. Bioassay guided fractionation of this extract led to the isolation of three compounds which inhibited the growth of three C. albicans strains. Based on spectroscopy studies (NMR and MS), the compounds were identified as 3β-hydroxyurs-12-en-28-oic acid, ursolic acid (1) 3β, 19α-dihydroxyurs-12-en-28-oic acid, pomolic acid (2) and 2β, 3β, 19α -trihydroxy-urs-12-en-28-oic acid, 2-epi-tormentic acid (3). The most active compound was 3β, 19α-dihydroxy-12-ursen-28-oic acid (2) with a minimum inhibitory concentration (MIC) value of 12.5 µg/mL for C. albicans isolated from dog and 25.0 µg/mL for C. albicans from cat and ATCC 90028 at 24 h following incubation. However, at 48 h of incubation MICs were > 400 µg/mL for all the three compounds isolated. This study indicated that M. obtusifolia could be a potential source of active principles against C. albicans.     

C-glycosylflavones from roots of glycine max

Chemical investigation of the roots of Glycine max yielded six C-glycosylflavones identified on the basis of spectral data as carlinoside, isocarlinoside, vitexin, vitexin 2″-O-rhamnoside, isoschaftoside and a new compound 6,8-di-C-hexosylgenkwanin.