Two octahydro-protoberberine alkaloids, alangiifoliumines A (1) and B (2), and two new protoemetine derivatives, alangiifoliumines C (3) and D (4), together with 11 known compounds, have been isolated from the stems of Alangium salviifolium. While the structures of these compounds were elucidated by spectroscopic methods, the absolute configurations of the new alkaloids were determined by conformational analysis and time-dependent density functional theory–electronic circular dichroism spectra calculations on selected stereoisomers. Compounds 1 and 2 represent the first 5,8,8a,9,12,12a,13,13a-octahydro-protoberberine derivatives, in which the aromatic ring D was reduced to cyclohexene. All the compounds isolated were evaluated for their cytotoxic activity against three human cancer cell lines: A-549, HeLa, and SKOV-3. Alkaloids 1, 3, and 6–14 exhibited inhibitory effects against all three human cancer cell lines, with half-maximal inhibitory concentration (IC50) values in the range of 3 nM to 9.4 μM.

Applying remote sensing techniques to develop the retrieval models and further to obtain the spatiotemporal information of water quality parameters is necessary for understanding, managing, and protecting lake ecosystems. This study aimed to calibrate and validate the retrieval models for estimating the concentrations of chlorophyll a (C CHL), suspended particulate matter (C SPM), and dissolved organic carbon (C DOC) with the in situ hyperspectral measurements in Poyang Lake, China in 2010 and 2011. The model calibration and validation results indicated that: (1) for C CHL retrieval, significantly strong and moderate correlations existed between the measured and estimated values (with the correlation coefficient r = 0.92 and r = 0.76) using the exponential model and the three-band model, respectively, with biased estimation observed for the exponential model; (2) for retrieving C SPM , there was a strong correlation between the measured and estimated values (r = 0.95) using the exponential model; and (3) no significant correlation between measured and estimated C DOC values was found with our developed models. More work is needed to allow the water quality of Poyang Lake to be accurately and steadily estimated, especially for C CHL and C DOC .

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