Polysubstituted Isoflavonoids from Spatholobus suberectus,Flemingia macrophylla,and Cudrania cochinchinensis

Four hitherto unknown polysubstituted isofiavonoids,including three isofiavans:7,4'-dihydroxy-8,2',3'-trimethoxyisofiavan(1),7,2',4'-trihydroxy-8,3'-dimethoxyisofiavan(2),and 7,2',4'-trihydroxy-5-methoxyisofiavan(3),and one prenylated isofiavone cudraisofiavone M(4)were isolated from the ethanol extracts of Spatholobus suberectus(for 1 and 2),Flemingia macrophylla(for 3),and Cudrania cochinchinensis(for 4),respectively.Their structures were estab­lished on the basis of extensive spectroscopic analysis.Compounds 1 and 4 exhibited weak cytotoxic activity against five human cancer cell lines(HL-60,A-549,SMMC-7721,MCF-7,and SW-480).

Aristolane‑type Sesquiterpenoids from Nardostachys chinensis and Revised Structure of Aristolanhydride

Four hitherto unknown aristolane-type sesquiterpenes,including one novel 8,9-secoaristolane,namely secoaristolenedioic acid(1),two aristolone derivatives,namely 1α,2β-dihydroxyaristolone(2),9-epidebilon(3),and one rare aristolane-chalcone hybrid,namely 3′-hydroxynardoaristolone A(4)were isolated from the ethanol extract of the roots and rhizomes of Nardostachys chinensis.Their structures were elucidated on the basis of extensive spectroscopic analysis.In addition,the structure of aristolanhydride,recently isolated from the same species,was corrected by reanalysis of the published NMR data.

Using Support Vector Machine to Predict Eco-environment Burden:A Case Study of Wuhan,Hubei Province,China

Objective The human socio-economic development depends on the planet＇s natural capital. Humans have had a considerable impact on the earth, such as resources depression and environment deterioration. The objective of this study was to assess the impact of socio-economic development on the ecological environment of Wuhan, Hubei Province, China, during the general planning period 2006-2020. Methods Support vector machine （SVM） model was constructed to simulate the process of eco-economic system of Wuhan. Socio-economic factors of urban total ecological footprint （TEF） were selected by partial least squares （PLS） and leave-one-out cross validation （LOOCV）. Historical data of socio-economic factors as inputs, and corresponding historical data of TEF as target outputs, were presented to identify and validate the SVM model. When predicted input data after 2005 were presented to trained model as generalization sets, TEFs of 2005, 2006,…, till 2020 were simulated as output in succession. Results Up to 2020, the district would have suffered an accumulative TEF of 28.374 million gha, which was over 1.5 times that of 2004 and nearly 3 times that of 1988. The per capita EF would be up to 3.019 gha in 2020. Contusions The simulation indicated that although the increase rate of GDP would be restricted in a lower level during the general planning period, urban ecological environment burden could not respond to the socio-economic circumstances promptly. SVM provides tools for dynamic assessment of regional eco-environment. However, there still exist limitations and disadvantages in the model. We believe that the next logical step in deriving better dynamic models of ecosystem is to integrate SVM and other algorithms or technologies.

Prenylated Coumarins from Heracleum stenopterum,Peucedanum praeruptorum,Clausena lansium,and Murraya paniculata

Four hitherto unknown prenylated coumarins,namely 600-O-b-D-apiofuranosylapterin(1),40-O-isobutyroylpeguangxienin(2),6-(3-methyl-2-oxobutyroyl)-7-methoxycoumarin(3),and 6-hydroxycoumurrayin(4),were isolated from the ethanol extract of Heracleum stenopterum,Peucedanum praeruptorum,Clausena lansium,and Murraya paniculata,respectively.Their chemical structures were established on the basis of extensive spectroscopic analysis.Compound 2 exhibited in vitro cytotoxic activity against five human cancer cell lines(HL-60,A-549,SMMC-7721,MCF-7,and SW-480)with IC50 values ranging from 15.9 to 23.2μM.

New Iboga‑Type Indole Alkaloids from Tabernaemontana divaricata

Two hitherto unknown iboga-type indole alkaloids,namely(3R)-7,19-di-epi-3-methoxytabernoxidine(1)and(3R,19R)-19-hydroxy-3-(2-oxopropyl)voacangine(2),together with eight known alkaloids(3-10),were isolated from the twigs and leaves of Tabernaemontana divaricata.Their structures were established on the basis of spectroscopic data interpretation,single crystal X-ray diffraction analysis and circular dichroism spectrum.

Derrisisoflavones H-K and One Isoflavan Derivative from Derris robusta

Four hitherto unknown prenylated isoflavonoids,named derrisisoflavones H-K(1-4)and one new isoflavan,namely 6-hydroxyisosativan(5),were isolated from the ethanol extract of Derris robusta.Their structures were elucidated on the basis of extensive spectroscopic studies.To our knowledge,derrisisoflavones J(3)and K(4)are the first examples of hydroxyethylated isoflavonoid.

Pterocarpadiols A–D, Rare 6a,11b-Dihydroxypterocarpans from Derris robusta

Four hitherto unknown 6a,11b-dihydroxypterocarpans,namely pterocarpadiols A–D(1–4),were isolated from the ethanol extract of the twigs and leaves of Derris robusta.Their structures were elucidated on the basis of extensive spectroscopic analysis.Pterocarpadiols A–D are a kind of very rare 6a,11b-dihydroxypterocarpans,and their presence as markers may be helpful in chemotaxonomical classification.

ORGANIC/INORGANIC HYBRID EPOXY NANOCOMPOSITES BASED ON OCTA(AMINOPHENYL)SILSESQUIOXANE

Octa（aminophenyl）silsesquioxane （OAPS） was used as the curing agent of diglycidyl ether of bisphenol-A （DGEBA） epoxy resin. A study on comparison of DGEBA/OAPS with DGEBA/4,4＇-diaminodiphenyl sulfone （DDS） epoxy resins was achieved. Differential scanning calorimetry was used to investigate the curing reaction and its kinetics, and the glass transition of DGEBA/OAPS. Thermogravimetric analysis was used to investigate thermal decomposition of the two kinds of epoxy resins. The reactions between amino groups and epoxy groups were investigated using Fourier transform infrared spectroscopy. Scanning electron microscopy was used to observe morphology of the two epoxy resins. The results indicated that OAPS had very good compatibility with DGEBA in molecular level, and could form a transparent DGEBA/OAPS resin. The curing reaction of the DGEBA/OAPS prepolymer could occur under low temperatures compared with DGEBA/DDS. The DGEBA/OAPS resin didn＇t exhibit glass transition, but the DGEBA/DDS did, which meant that the large cage structure of OAPS limited the motion of chains between the cross-linking points. Measurements of the contact angle indicated that the DGEBA/OAPS showed larger angles with water than the DGEBA/DDS resin. Thermogravimetric analysis indicated that the incorporation of OAPS into epoxy system resulted in low mass loss rate and high char yield, but its initial decomposition temperature seemed to be lowered.