Chemical Constituents from Fruit Hulls of Garcinia mangostana ( Cuttiferae

从山竺(Garcinia mangostana)果壳中分离得到6个化合物,通过MS,1D 1NMR以及与文献对照鉴定它们为4个(口山)酮类化合物:α-mangostin(1),β-mangostin(2),γ-mangostin(3),5,9-dihydroxy-8-methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano-[3,2-b]-xanthen-6-one(4),以及表儿茶素(epicatechin,5)和一个双苄类化合物egonol(6).其中化合物5和化合物6为首次从该植物中分离得到.对化合物1～5进行抗HIV-1 RT活性筛选结果表明,化合物2和化合物5在浓度200 μg/ml的条件下,其对HIV-1 RT抑制率分别为41.97%和47.72%;同一实验结果显示化合物1,3和4没有抑制HIV-1 RT作用.

Chemical Constituents from the Leaves and Stems of Schisandra lancifolia

A new nortriterpenoid, 20-hydroxymicrandilactone D (1) and a novel lignan glycoside, lancilignanside A (2) were isolated from leaves and stems of Schisandra lancifolia, together with three known nortriterpenoids (3-5) and nine known phenolics (6-14). The structures of new compounds 1 and 2 were determined by detailed analysis of their 1D and 2D NMR spectra, and chemical evidences. In addition, compounds 1-2, 6-7, and 9-11 showed anti-human immunodeficiency virus (HIV)-1 activities with 50% effective concentration (EC50) in the range of 3.0-99.0 mu g/ml. Compound 12 was not bioactive in this assay with EC50 more than 200 mu g/ml.

Chemical Constituents from the Leaves and Stems of Schisandra rubriflora

Six new nortriterpenoids, schirubridilactones A-F (1-6). as well as 14 known compounds, were isolated from the leaves and stems of Schisandra rubriflora. The Structures of 1-6 were elucidated oil the basis of spectroscopic methods including HSQC, HMBC, H-1-H-1 COSY, and ROESY NMR experiments. The relative stereochemistry of I was confirmed through single-crystal X-ray analysis. In addition, compounds 1-6 showed anti-HIV-1 activity with EC50 values in the range 14.3-80.8 mu g/mL and Selectivity indices in the range 2.2-9.0.

Estimation of the natural purification rate of a eutrophic lake after pollutant removal

Pollution resulting from increased human activities is threatening Lake Donghu, its effects being characterized by serious eutrophication. A steady increase of phosphorus loading is the most important factor of the lake eutrophication. Pollution external control projects are being implemented and will be accomplished before the year 2010. In order to predict the restoration rate by the lake's self-purification after the projects of external control, a model of predicting the removal rate of total phosphorus (TP) from lake water is developed, and a brief method of estimating the release and export rate of sediment phosphorus is suggested. Results show that, on the premise of external loading fully controlled. The restoration needs about 55 years or more. Obviously, the great P pool in the sediment will be a limiting factor of preventing the improvement of water quality after the external loading is under control. Based on the estimation we conclude that after the external control projects before 2010, in order to restore the lake in a few years, although highly cost, the first step must be the sediment dredging to remove internal loading. The second step is diverting water of River Changjiang into the lake to accelerate the improvement of lake water. Otherwise, removal of pollutant sources will become meaningless. (c) 2006 Elsevier B.V. All rights reserved.

Physico-chemical properties of alkaline phosphatases released by a planktonic crustacean, Daphnia magna (Cladocera)

Our studies investigated the physico-chemical properties of alkaline phosphatase excreted by D. magna. This cladoceran mainly released alkaline phosphatase, though it also released a small amount of acid phosphatase. The alkaline phosphatase showed a broad pH optimum (8.05-10.0), and had a broad optimum temperature (30-35 degrees C) with a temperature coefficient (Q(10)) of 2.45. The K-m of the enzyme is 0.15 +/- 0.02 mM when p-nitrophenyl phosphate is used as a substrate, and the V-max is 0.43 +/- 0.01 mu M pNP mg(-1) DW h(-1). Even though alkaline phosphatase had been incubated in chloroform saturated with WC medium for 13 days, its activity was 54% that of the original. The enzyme was strongly inactivated by EDTA, and appeared to be zinc dependent. The alkaline phosphatase activity remained constant when D. magna was fed different quantities of Chlorella sp. The sensitivity of D. magna phosphatase activity to phosphate was time-dependent. During the first 16 hrs, the enzyme was insensitive to phosphate addition, after 24 hrs incubation the enzyme became sensitive to phosphate addition.