Carbohydrates play essential roles in nature, such as in cell–cell communication, cell growth and immunoresponse. However, the synthesis of structurally well-defined carbohydrates, especially large-sized glycans, is a challenging task. Here we report an automated solution-phase multiplicative synthesis of complex glycans enabled by preactivation-based, multicomponent, one-pot glycosylation and continuous multiplying amplification. This was achieved by making a dual-mode automated solution-phase glycan synthesizer. Using this synthesizer, a library of oligosaccharides covering various glycoforms and glycosidic linkages was assembled rapidly, either in a general promoter-activation mode or in a light-induced-activation mode. The automated synthesis of a fully protected fondaparinux pentasaccharide (an anticoagulant) was realized on the gram scale. Furthermore, automated ten-component tandem reactions were performed, allowing the assembly of arabinans up to a 1,080-mer using this automated multiplicative synthesis strategy. The complexity of carbohydrate structures makes their synthesis challenging. Now, an automated glycan synthesizer is reported which is capable of preparing a library of bioactive oligosaccharides, including a fully protected fondaparinux pentasaccharide. Furthermore, the synthesizer can rapidly assemble arabinans up to 1,080-mer size, starting from monosaccharide building blocks.

Mycobacterial arabinogalactan (AG) is an essential cell wall component of mycobacteria and a frequent structural and bio-synthetical target for anti-tuberculosis (TB) drug development. Here, we report that mycobacterial AG is recognized by galectin-9 and exacerbates mycobacterial infection. Administration of AG-specific aptamers inhibits cellular infiltration caused by Mycobacterium tuberculosis (Mtb) or Mycobacterium bovis BCG, and moderately increases survival of Mtb-infected mice or Mycobacterium marinum-infected zebrafish. AG interacts with carbohydrate recognition domain (CRD) 2 of galectin-9 with high affinity, and galectin-9 associates with transforming growth factor β-activated kinase 1 (TAK1) via CRD2 to trigger subsequent activation of extracellular signal-regulated kinase (ERK) as well as induction of the expression of matrix metalloproteinases (MMPs). Moreover, deletion of galectin-9 or inhibition of MMPs blocks AG-induced pathological impairments in the lung, and the AG-galectin-9 axis aggravates the process of Mtb infection in mice. These results demonstrate that AG is an important virulence factor of mycobacteria and galectin-9 is a novel receptor for Mtb and other mycobacteria, paving the way for the development of novel effective TB immune modulators.

To investigate the chemical components from the stems of Casearia velutina Bl.,the constituents were isolated by repeated chromatography with silica gel,Sephadex LH-20,and ODS columns.The structures were elucidated by spectroscopic analysis.Eleven triterpenoids and its glycosides were isolated from the crude extract of C.velutina,and their structures were identified as friedelin-2,3-1actone (1),friedelane (2),epifriedelanol (3),friedelin (4),2α,3α,19α-trihydroxy-urs-12-cn-28-oic acid (5),2α,3β,19α-trihydroxy-urs-12-en-28-oic acid (6),2α,3α,23-trihydroxy-urs-12-en-28-oic acid (7),2α,3α,23-trihydroxyolean-12-en-28-oic acid (8),2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid (9),2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid-28-O-β-D-glucopyranosyl ester (10),and 3β,19α-dihydroxy-urs-12-en-28-oic acid 3-O-α-L-arabinopyranoside (11).All the compounds described above were isolated from this species for the first time.Compound 1 is a rarely occurred secofriedelolactone in Flacourtiaceae.

Chemical investigation of the stems of Casearia velutina led to the isolation and structural elucidation of three new acylated glycosides, casearicosides A-C (1-3), together with 13 known compounds. The structures of the new compounds were established by spectroscopic and chemical methods. These isolates were evaluated for protective effects against H(2)O(2)-induced impairment in PC12 cells and inhibitory activity against snake venom phosphodiesterase I. A brief chemotaxonomy of the genus Casearia is also discussed.

Investigations of two Flacourtiaceae plants, Bennettiodendron leprosipes and Flacourtia ramontchi, resulted in the isolation and structural elucidation of six new constituents including two phenolic glycosides ( 1 and 2), one lignan ( 3), two lignan glycosides ( 4 and 5), and a monoterpene glycoside ( 6), together with 22 known compounds ( 7- 28). The structures of the new compounds were elucidated by spectroscopic analysis and chemical methods. The selected isolates 1, 2, 8- 10, 22- 26, and some phenolic glycosides 29- 42 previously isolated from another Flacourtiaceae plant, Itoa orientalis, were tested against snake venom phosphodiesterase I (PDE I) activity. The result indicated that 22, 30, 32, 34, and 40 exhibited moderate inhibitory activities against PDE I with the values ranging from 13.15 to 20.86 %, and 1, 8, 10, 25, 31, 33, 35, 38, 39, and 41 showed weak inhibitory activity.

Four rare isoryanodane diterpenoids namely itols A–D (1–4) and two isoryanodane glucosides (5 and 6) were isolated from the bark and twigs of Itoa orientalis. Their structures were determined by NMR and MS techniques and the structure of 1 was confirmed by a single-crystal X-ray diffraction. These six diterpenoids obviously showed insecticidal activity against Spodoptera exigua, with LC50 28.62 ppm for 1 and 52.76 ppm for 2, respectively. In anti-inflammatory assay, compounds 1 and 4–6 showed anti-COX-2 activity, with inhibitory rates of 54.7–78.3% at 10 μM.

Eight new benzoylated gentisyl alcohol (=2-(hydroxymethyl)benzene-1,4-diol) glucosides, itosides A-H (1-8), together with the new pyrocatechol (= benzene- 1,2-diol) glycoside itoside 1 (9) were isolated front the bark and twigs of Itoa orientalis (Flacourtiaceae). In itosides B-D (2-4), the gentisyl alcohol moiety was esterified by 1-hydroxy-6-oxocyclohex-2-ene-1-carboxylic acid, while itosides E-H (5-8) contained instead an additional 2-hydroxybenzoic acid moiety. The compounds were accompanied by the known derivatives 4-hydroxytremulacin (10), poliothyrsoside (11), poliothyrsin (12). homaloside D (13), tremulacin, and pyrocatechol beta-D-glucopyranoside. The structures of the new compounds were elucidated by spectral and chemical methods.

目的研究爪哇脚骨脆Casearia velutina茎及枝条的化学成分。方法采用多种现代色谱手段对其化学成分进行分离,利用理化性质并结合光谱数据鉴定化合物结构。结果分离鉴定了9个化合物,分别为:丁香酸葡萄糖苷(Ⅰ)、儿茶素(Ⅱ)、腺嘌呤核苷(Ⅲ)、(2R,3S,4R,5R)-直链肌醇(Ⅳ)、5-p-trans-coumaroylquinic acid(Ⅴ)、3′-O-methylquercetin3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside(Ⅵ)、(3S,6R)-trans-linalool-3,7-oxideglucoside(Ⅶ)、蔗糖(Ⅷ)、果糖(Ⅸ)。结论该9个化合物均为首次从爪哇脚骨脆中分离得到。

AIM:To investigate the chemical constituents from the leaves of Itoa orientalis Hemsl..METHODS:Chromatography of silica gel,Sephadex LH-20 and ODS and spectral analysis of MS,1D and 2D NMR were respectively used to isolate and identify the constituents.RESULTS:Five compounds were isolated from the leaves of Itoa orientalis Hemsl..and identified as β-D-galactopyranoside,2,3-bis[(1-oxo-9,12,15-octadecatrienyl)oxy]propyl(1),β-D-galactopyranoside,2,3-bis[(1-oxo-hexadecyl)oxy]propyl-6-O-α-D-galactopyranyl(2),β-D-galactopyranoside,(2S)-3-[[(9Z,12Z)-1-oxo-9,12-octadecadienyl]oxy]-2-[[(9Z,12Z,15Z)-1-oxo-9,12,15-octadecatrienyl]oxy]propyl-6-O-α-D-galactopyranosyl(3),gingerglycolipid A(4)and(3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetrol 3-O-β-D-glucopyranoside(5).CONCLUSION:All compounds were isolated from the genus for the first time,among which the NMR data of compound 1 was firstly reported.

挪挪果Flacoutia ramontchii L.,又名大果刺篱木,在当地也称为山李子等,为大风子科刺篱木属常绿乔木,多生于海拔200～1700 m的常绿阔叶林中或以壳斗科Fagaceae植物为主的常绿阔叶林中[1],主产广西、贵州及云南等省区[2].

伊桐Itoa orientalis Hemsl.又名栀子皮、野厚朴等,为大风子科伊桐属植物,常绿乔木,主要分布于我国的西南和广西地区,在民间主要用于风湿痹痛,跌打损伤,肝炎及贫血等症状,药用其根和树皮,名为大黄树[1].