Chemical constituents from the stem bark of Acer tegmentosum

A new phenolic glycoside, 4-hydroxyphenylethyl-1-O-β-D-[6′-O-(4-hydroxybenzoyl)]-glucopyranoside (1) was isolated from the stem bark of Acer tegmentosum, along with seven known phenolic compounds (2–8). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. Compounds 3 and 4 were found in the family Aceraceae for the first time.     

Isolation and identification of an anticancer compound from the bark of Acer tegmentosum Maxim

In this study, we investigated the anticancer activity of a newly isolated compound from Acer tegmentosum Maxim (ATM) in HepG2 cells. This compound was isolated by reverse-phase high-performance liquid chromatography (RP-HPLC) in a butanol-soluble fraction, which was shown to have the strongest anticancer activity. The isolated compound was identified as salidroside using multiple nuclear magnetic resonance (NMR) techniques, including ¹H, ¹³C, correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC), as well as electrospray ionization mass spectroscopy (ESI/MS). The activity of salidroside was evaluated in HepG2 cells by analyzing cell proliferation, cell cycle distribution, Hoechst 33342 staining, and Western blots of apoptotic regulatory proteins. The results show that salidroside, an anticancer compound from ATM, exhibits strong apoptotic activity in HepG2 cells. Therefore, ATM extracts could be used as chemotherapeutic agent to induce apoptosis in hepatoblastoma cells.     

Two new flavonoid glycosides from Iris tectorum

Phytochemical investigation of the ethanol extract of rhizomes of Iris tectorum resulted in the isolation and characterization of two new flavonoid glycosides, tectorigenin-7-O-β-d-fucopyranoside (1), 3,5,4′-trihydroxy-7,3′-dimethoxyflavanone-5-O-α-l-rhamnopyranoside (2), together with two known ones (3, 4). The rhamnose substituent at C-5 displayed uncommon connection in naturally occurring flavonoid glycosides. Their structures were elucidated on the basis of extensive spectroscopic analysis. All of the isolates were evaluated for their in vitro inhibitory activity against aldose reductase.     

A new flavonoid from the bark of Ulmus pumila L

A new flavonoid (6), together with eight (1–5 and 7–9) known flavonoids, were isolated from the n-butyl alcohol soluble portion of the EtOH extract of Ulmus pumila L. The chemical structures of the compounds were determined by using spectroscopic methods and further supported by comparison with previously literature values. Among them, flavonoids 4, 6 and 9 were isolated for the first time from the family Ulmaceae. Furthermore, the chemotaxonomic significance of the isolates was also discussed.     

Two flavonoid glycosides and a miscellaneous flavan from the bark of Guibourtia coleosperma

Two flavonoid glycosides, 7-O-beta-D-xylopyranosyl-epicatechin and epicatechin-(4beta-->8)-7-O-beta-D-xylopyranosyl-epicatechin both as their acetate and methyl ether acetate derivatives and a miscellaneous flavan Epicatechin-(7,8-bc)-9beta-(3-methoxy-4-acethoxyphenyl)-dihydro-2(3H)-pyranone as its acetate derivative were isolated from the bark of Guibourtia coleosperma. Their structures were established by spectroscopic methods.     

Three new compounds from the bark of Antiaris toxicaria

Three new compounds, namely (+)-pranferol (1), antiarone M (2), and anticerol A (3), together with 9 known compounds, were obtained from the bark of Antiaris toxicaria. Their chemical structures were elucidated on the basis of spectroscopic methods including UV, IR, (HR) ESI–MS, ¹H, ¹³C NMR, HSQC, ¹H-¹H COSY, HMBC and X-ray crystallographic technique. The absolute configurations of compounds 1 and 2 were determined by modified mosher method and CD spectrum.     

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.     

元宝槭树叶中的黄酮苷

从槭树科植物元宝槭(AcertruncatumBunge)树叶中分离得到6个黄酮苷化合物。通过波谱分析鉴定其结构分别为:kaempferol-3-O-α-L-rhamnopyranoside(1);quercetin-3-O-β-D-galactopyranoside(2);quercetin-3-O-α-L-rhamnopyranoside(3);quercetin-3-O-α-L-arabinopyranoside(4);isorhamnetin-3-O-α-L-arabinopyranoside(5);myricetin-3-O-α-L-rhamnopyranoside(6)。     

A new chromane derivative from the stem bark of Scyphocephalium ochocoa

A new chromane, 5,8-dihydroxy-2-(10′-phenyldecyl)chroman-4-one (1) was isolated from the stem bark of Scyphocephalium ochocoa, along with three known compounds (2–4). The structure of compound 1 was determined with help of spectroscopic data including IR, UV, HREIMS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. Furthermore, the chemotaxonomic significance of these compounds along with other compounds previously isolated from Scyphocephalium ochocoa was discussed.     

Two flavonoid glycosides from the bark of Prosopis juliflora

Two new glycosides, kaempferol 4′-methyl ether 3-O-β-d-galactopyranoside and retusin 7-O-neohesperidoside, have been characterized from the stem bark of Prosopis juliflora.     

Astringent tannins of Acer species

All 25 species of Acer examined contain condensed (proanthocyanidins) and hydrolysable (gallo- and/or ellagi-) tannins, but each of these varies ov     

Systematic aspects of the astringent tannins of Acer species

Leaves of a further 25 species of Acer, mostly from Asia and N. America, show similar levels of astringency and distribution of condensed and hydrolysable tannins to those previously examined. The results are tabulated and discussed in accordance with de Jong's recent rearrangement of the genus.     

A fluorescence quenching test for the detection of flavonoid transformation

A novel fluorescence quenching test for the detection of flavonoid degradation by microorganisms was developed. The test is based on the ability of the flavonoids to quench the fluorescence of 1,6-diphenyl-1,3,5-hexatriene (DPH). Several members of the anthocyanidins, flavones, isoflavones, flavonols, flavanones, dihydroflavanones, chalcones, dihydrochalcones and catechins were tested with regard to their quenching properties. The anthocyanidins were the most potent quenchers of DPH fluorescence, while the flavanones, dihydroflavanones and dihydrochalcones, quenched the fluorescence only weakly. The catechins had no visible impact on DPH fluorescence. The developed test allows a quick and easy differentiation between flavonoid-degrading and flavonoid-non-degrading bacteria. The investigation of individual reactions of flavonoid transformation with the developed test system is also possible.     

Zanoxyline—a new alkaloid from stem bark of Zanthoxylum oxyphyllum

The EtOH extract of stem bark of Zanthoxylum oxyphyllum yielded rhetsinine and a new alkaloid 1-(4′methoxy benzyl)-6,7-dimethoxy N:N dimethyl 1,2,3,4 tetrahydroisoquinolinium hydroxide provisionally named zanoxyline.     

Seven new vernocuminosides from the stem bark of Vernonia cumingiana Benth

Seven new stigmastane-type steroidal glycosides, vernocuminosides H-N, have been isolated from the stem bark of Vernonia cumingiana Benth. The structures of these compounds were determined by NMR spectrometric methods including HSQC, HMBC, ¹H-¹H COSY, and NOE, as well as circular dichroism experiments. Anti-inflammatory activities of vernocuminosides I and K-N were determined.