Perspectives on Fragment-based Drug Discovery: A Strategy Applicable to Diverse Targets.

Fragment-Based Drug Discovery (FBDD) is a strategy to develop potent lead molecules and is frequently used in drug discovery projects of the pharmaceutical industry. This method starts from identifying a small-molecule fragment, which usually binds weakly to the target and follows with a hit-to-lead step in which the fragment is grown into potent molecules that bind tightly to the target to affect its function. Quite a few drugs and compounds in clinical trials are developed using this approach, making FBDD a powerful strategy in drug discovery. FBDD can be applied to multiple targets and the hit rate in screening can be used in target druggability assessment. In this minireview, we provide a summary of the development of FBDD. In addition to giving a brief summary of the methods used in fragment screening, we highlight some methods that are critical in fragment growth. Biophysical methods and careful chemical modification of the fragments are the key elements in FBDD. We show several strategies that can be utilized in FBDD. We emphasize that NMR spectroscopy such as 19F-NMR and 1H-5N-HSQC experiment and X-ray crystallography are important in FBDD due to their roles in fragment screening and understanding the binding modes of the fragment hits, which provides a strategy for fragment growth.

Isolation, characterization and application of a cellulose-degrading strain Neurospora crassa S1 from oil palm empty fruit bunch.

BACKGROUND: Oil palm empty fruit bunch (EFB) is a lignocellulosic waste produced in palm oil industry. EFB mainly consists of cellulose, hemicellulose (mainly xylan) and lignin and has a great potential to be reused. Converting EFB to fermentable sugars and value-added chemicals is a much better choice than treating EFB as waste. RESULTS: A cellulase-producing strain growing on oil palm empty fruit bunch (EFB) was isolated and identified as Neurospora crassa S1, which is able to produce cellulases using EFB as the sole carbon source. The strain started to secret cellulases into the medium after 24 h of cultivation at 30°C and reached its maximal cellulase activity at 240 h. Mass spectroscopy (MS) analysis showed that more than 50 proteins were secreted into the medium when EFB was used as the sole carbon source. Among them, 7 proteins were identified as putative enzymes associated with cellulose degradation. The whole cell culture of Neurospora crassa S1 was used to hydrolyze acid-treated EFB, giving a total sugar yield of 83.2%, which is comparable with that (82.0%) using a well-known cellulase producer Trichoderma reesei RUT-C30 (ATCC56765). CONCLUSION: Neurospora crassa S1 is a commercially promising native cellulase producer for EFB hydrolysis especially when the sugars obtained are to be fermented to products that require use of non-genetically engineered strains.

Efficient production of fermentable sugars from oil palm empty fruit bunch by combined use of acid and whole cell culture-catalyzed hydrolyses.

Empty fruit bunch (EFB) of oil palm trees was converted to fermentable sugars by the combined use of dilute acids and whole fungal cell culture-catalyzed hydrolyses. EFB (5%, w/v) was hydrolyzed in the presence of 0.5% H2 SO4 and 0.2% H3 PO4 at 160 °C for 10 Min. The solid fraction was separated from the acid hydrolysate by filtration and subjected to enzymatic hydrolysis at 50 °C using the whole cell culture of Trichoderma reesei RUT-C30 (2%, w/v), which was prepared by cultivation at 30 °C for 7 days to reach its maximal cellulase activity. The combined hydrolyses of EFB gave a total sugar yield of 82.0%. When used as carbon sources for cultivating Escherichia coli in M9 medium at 37 °C, the combined EFB hydrolysates were shown to be more favorable or at least as good as pure glucose for cell growth in terms of the higher (1.1 times) optical density of E. coli cells. The by-products generated during the acid-catalyzed hydrolysis did not seem to obviously affect cell growth. The combined use of acid and whole cell culture hydrolyses might be a commercially promising method for pretreatment of lignocellulose to get fermentable sugars.

Two new coumarins from Micromelum falcatum with cytotoxicity and brine shrimp larvae toxicity.

Two new coumarins, 7-methoxy-8-(2-hydroxmethyl-1-O-isovaleryl-4-butenyl)-coumarin (1) and 7-methoxy-8-(1-hydroxy-2-O-ß-glucopyranosyl-3-methyl-4-butene-1-yl)coumarin (2), and twelve known coumarins 3-14 were isolated from the stem bark of Micromelum falcatum. The structures of compounds 1-14 were elucidated by extensive spectroscopic data analyses. The toxicity of compounds 1-14 was tested using a brine shrimp assay and in vitro antiproliferative assay against mammary cancer (F10) and lung cancer (HvEvc) cell lines by the MTT method. Some compounds had moderate activities. All compounds were also tested against the microorganisms Bacillus subtilis, Bacillus thuringiensis and Escherichia coli, but no activity was observed.

[Studies on the chemical constituents of Scyphiphora hydrophyllacea (II)].

OBJECTIVE: To study the chemical constituents of Scyphiphora hydrophyllacea. METHODS: The compounds were isolated and purified by repeated column chromatography on silica and Sephadex LH-20 gel and their structures were identified by spectral analysis. RESULTS: Six compounds were identified as friedelin (1), syringic acid (2), isoscopoletin (3), fraxetol (4), casuarinondiol (5) and guaiacylglycerol-beta-ferulic acid ether (6). CONCLUSION: All of these six compounds are isolated from Scyphiphora hydrophyllacea for the first time.

Complete 1H and 13C NMR assignments of four new steroidal glycosides from a gorgonian coral Junceella juncea.

Four new cholest-type steroidal glycosides, junceellosides A-D, isolated from the EtOH/CH(2)Cl(2) extracts of the South China Sea gorgonian coral Junceella juncea, were identified. Complete assignments of the (1)H and (13)C NMR chemical shifts for these compounds were achieved by means of one- and two-dimensional NMR techniques, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectra.

Complete assignments of 1H and 13C NMR data for 10 phenylethanoid glycosides.

Ten phenylethanoid glycosides, including two new ones, isolated from the aerial parts of the mangrove plant Acanthus ilicifolius were identified. The first complete assignments of the 1H and 13C NMR chemical shifts for these glycosides were achieved by means of 2D NMR techniques, including 1H-1H COSY, TOCSY, HSQC and HMBC spectra.

[Preventive and treatment effect of composite Rhodiolae on acute lung injury in patients with severe pulmonary hypertension during extracorporeal circulation].

OBJECTIVE: To investigate the possibility of early prevention and treatment of acute lung injury by using composite Rhodiolae (CR) in patients with severe pulmonary hypertension during extracorporeal circulation. METHODS: Seventy-six patients with severe pulmonary hypertension screened out by color 2D-Doppler ultrasonography were randomly divided into the treated group (n = 40) and the control group (n = 36). The general treatment for the two groups, including preoperational preparation, operational procedure and conventional drug therapy, was the same. To the treated group, CR was administered 4 g every day (half the dose in children) at 7-10 day before and 5-7 day after the operation. The life signs, pulmonary ventilation parameters, arterial blood gas analysis were monitored and blood levels of TXB2, 6-keto-PGF1 alpha in both groups were determined in the fixed time points. RESULTS: The various parameters in the treated group were all better than those in the control group (P < 0.05 or P < 0.01), the occurrence rate of acute lung injury and its mortality in the treated group were 7.5% (3/40) and 0% (0/3) respectively, while in the control group were 19.4% (7/36) and 43% (3/7) respectively. CONCLUSION: CR has good preventive and treatment effect in treating complicated acute lung injury during extracorporeal circulation (cardiopulmonary bypass) in patients with pulmonary hypertension.

New aliphatic alcohol and (Z)-4-coumaric acid glycosides from Acanthus ilicifolius.

From the aerial parts of Acanthus ilicifolius, a new aliphatic alcohol glycoside (ilicifolioside C) and two new (Z)-4-coumaric acid glycosides, (Z)-4-coumaric acid 4-O-beta-D-glucopyranoside and (Z)-4-coumaric acid 4-O-beta-D-apiofuranosyl-(1"-->2')-O-beta-D-glucopyranoside were isolated. The structural elucidations were based on the analyses of spectroscopic data. Z-Form 4-coumaric acid glycosides were first isolated from plant.