Structure of ulososide A,a new triterpenoid glycoside from theUlosa sp. sponge

A new triterpenoid glycoside, (20S,22S,23R,24S)-3,22,23-trihydroxy-3-O-[O-(-D-glucuronopyranosyl)-(16)-(-D-glucopyranosyl)]-14-nor-24-methyllanost-8(9)-en-31-oic acid (ulososide A), has been isolated from the sponge Ulosa sp. and characterized.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1326–1329, July, 1994.     

A New Furostanol Saponin from Dioscorea futshauensis

A new furostanol saponin presenting moderate bioacitivity of inducting morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R.Kunth by bioacitivity-guided fractionation. The structure was established as 26-O-β-D-glucopyranosyl-3β,26-diol-23(S)-methoxyl-(25R)-furost-5,20(22)-diene-3-O-[α-L-rhamnopyranosyl(1→2)-β-D-glucopyranosyl(1→3)]-β-D-glucopyranoside on the basis of chemical evidencesand spectral analysis,especially by 2D-NMR techniques.     

Two New Steroidal Glycosides from Liriope muscari

Liriope muscari (Decn.) Bailey (Liliaceae) is a folk medicinal plant used as a substitute of Ophiopogon japonicus (Thunb.) Ker-Gawl., mainly distributing in Quanzhou, Fujian Province, China1. Previously, we reported the isolation and identification of two…     

A new enzyme catalysis: 3,4-dioxidation of some aryl β-d-glycopyranosides by fungal pyranose dehydrogenase

Quinone-dependent pyranose dehydrogenase presents a new tool for versatile conversions of numerous carbohydrates to their di- and tricarbonyl derivatives. This enzyme purified from the basidiomycete Agaricus meleagris catalysed dioxidation of several aromatic β-d-glucopyranosides and a β-d-xylopyranoside into the corresponding 3,4-didehydro-β-d-aldopyranosides (β-d-aldopyranosid-3,4-diuloses) in high yields, typically >80% for 4-nitrophenyl glycosides. These new compounds were doubly hydrated in aqueous solution. According to in situ NMR investigations, the reaction intermediates were the corresponding 3- and 4-dehydro compounds. The analogous anomeric α-glycosides underwent one-step oxidation only at C-3 to 3-dehydro-α-d-aldopyranosides (α-d-pyranosid-3-uloses).     

A validated solid-liquid extraction method for the HPLC determination of polyphenols in apple tissues Comparison with pressurised liquid extraction

A solid-liquid extraction procedure followed by reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a photodiode array detector (DAD) for the determination of polyphenols in freeze-dried apple peel and pulp is reported. The extraction step consists in sonicating 0.5 g of freeze-dried apple tissue with 30 mL of methanol-water-acetic acid (30:69:1, v/v/v) containing 2 g of ascorbic acid/L, for 10 min in an ultrasonic bath. The whole method was validated, concluding that it is a robust method that presents high extraction efficiencies (peel: >91%, pulp: >95%) and appropriate precisions (within day: R.S.D. (n = 5) <5%, and between days: R.S.D. (n = 5) <7%) at the different concentration levels of polyphenols that can be found in apple samples. The method was compared with one previously published, consisting in a pressurized liquid extraction (PLE) followed by RP-HPLC-DAD determination. The advantages and disadvantages of both methods are discussed.     

石香薷中两个新黄酮甙的研究

石香薷中两个新黄酮甙的研究郑尚珍，孙丽萍，沈序维王毅（西北师范大学化学系，兰州，７３００７０）（中国科学院兰州化学物理研究所）关键词石香薷，唇形科，黄酮甙唇形科植物石香薷（ＭＯｓｌａｃｈｉｎｅｎｓｉｓＭａｘｉｍ）作为中药，用来治疗暑湿感冒、头痛、腹痛...     

Synthesis of Floridoside

Floridoside (2-O-glycerol-α-D-galactopyranoside) is a natural glycerol glycoside found in red algae and is believed to play important roles in carbon storage, transport, and assimilation and in the regulation of osmotic balance. We describe here a rapid, high-yield, and high-stereoselectivity synthesis of floridoside in which the key step involves the 1,2-cis O-glycosylation of 1,3-dibenzylglycerol with ethyl 2,3,4,6-tetra-O-benzyl-1-thio-β-D-galactopyranoside using iodonium dicollidine perchlorate (IDCP) or N-iodosuccinimide/trimethylsilyl triflate (NIS/TMSOTf) as promoters.     

A phenolic glycoside from Fagopyrum dibotrys (D.Don) Hara

A new phenolic constituent along with five known compounds were isolated from Fagopyrum dibotrys(D.Don)Hara.The new compound was characterized as 1,3-dimethoxy-2-O-β-xylo-pyranosyl-5-O-β-glucopyranosyl-benzene,by spectroscopic analysis and enzymatic hydrolysis.     

One-step syntheses of alkyl glycosides and alkyl-substituted DNA oligomers by chemoselective glycosidations using DNA bases

The simple and practical synthesis of alkyl glycosides by novel chemoselective glycosidations using natural resources, DNA and RNA nucleosides, was realized, and the one-step synthesis of chemoselectively modified DNA oligomers using the glycosidation method was also demonstrated.