| Nansi Lake is the important regulation and storage zone of the eastern route of the South-to-North Water Diversion Project. To ensure the water quality of transfer project and the ecological safety of the basin, the basin pollution control strategy of "Treatment, Recycle, Restoration" was conducted in the past few years. The purification function of ecosystem is the principle of restoration strategy, and the restoration measure have had been carried out with large scale wetland rehabilitation and reconstruction project. After years of operation, the monitoring data indicated that the wetland ecosystem made significant contribution to the basin pollutants removal, non-point pollution buffer, and ecological restoration. However, with the remarkable achievements, there are still some challenges during the wetland rehabilitation and reconstruction including the long term efficient and sustainability of constructed wetland and the large financial gap of the ecological compensation for occupied cropland. Under such circumstances, the utilization of wetland plant resource become a crucial technology that would support the wetland rehabilitation and the long term sustainability of constructed wetland, and the idea status of ecosystem reconstruction is self-support drove by wetland resource utilization. The scientific problem that we intend to address in this study is how to develop an appropriate utilization pattern that could match the characteristics of constructed wetland plant resource. To solve this problem, a novel constructed wetland plant resource utilization pathway in the perspective of antitumor activity natural products was proposed.An analysis of the sources of drugs indicates that natural products play a highly significant role in the drug discovery and development process. Over 50% of all anticancer drugs are natural product or are derived from natural product with semi-synthetic modification. However, due to the low concentration of activities natural products in plant, a large amount of biomass is required when plant is used as raw material in industry scale. Therefore, it is a feasible approach to screen natural products as sources of human health care industry from constructed wetland plant species.In this study, several field surveys were conducted to investigate the wetland plant resource of Nansi Lake area. A total 126 species of 116 genus from 46 families were recorded.Four wetland plant species with different ecological types were selected based on the field investigation of Nansi Lake area. They are Nymphoides peltatum (Gmel.) O. Kuntze, Potamogeton crispus L, Nelumbo nucifera Gaertn and Alternanthera philoxeroides (Mart.) Griseb. Total secondary metabolites of these plants were extracted, then the antitumor activities of the extracts was evaluated by MTT assay with human prostate cancer cell line PC3 and human osteosarcoma cell line U2OS. The result showed that the extracts of N. nucifera, P. crispus and N. peltatum possess the relative high tumor inhibition activity, according the current utilization situation P. crispus and N.peltatum were selected for further study.The total secondary metabolites of N. peltatum were extracted and then grouped by MCI chromatography based on polarity, and repartitioned into three parts according to HPLC analysis data. The result of MTT assay indicates that 10% H2O-MeOH group of N. peltata extracts had a significant inhibition effect on PC3 and U2OS cell lines in a concentration-dependent manner, and the PC3 cells were more sensitive to the extracts. Then, further column chromatography was conducted on 10% H2O-MeOH group to isolate its main constituents. Based on Q-TOF-MS/MS spectra data combined with the Agilent TCM database, METLIN database, and spectrum data of standard compounds, four main constituents of 10% H2O-MeOH group were identified as ephedrine, ephedradine C,4-hydroxy-coumarine, and Delta-1-dehydrotanshinone. These compounds have been primarily reported to be associated with N. peltata.The total secondary metabolites of P.crispus were extracted, and separated into three parts by extraction with petroleum ether, ethyl acetate, and n-butyl alcohol respectively. Then, the cytotoxicity assay was carried out with ES-2 human ovarian cancer cell line and MDA-MB-231 human breast cancer cell line. The results indicated that the P. crispus EtOAc extract showed anti-tumor activities against MDA-MB-231 cells, and then morphological observation, cell cycle and death analysis were conducted to evaluate the cytotoxic activity. Results showed that the P. crispus EtOAc extract could change the cell morphology and block the MDA-MB-231 cell cycle at S phase, and the mechanism of cell death were apoptosis and necrosis. Six compounds were isolated from P. crispus EtOAc extract, This study provide scientific base for a potential utilization of constructed wetland plant P.crispus and has implications for sustainable running of constructed.In order to further explore the efficient utilization of plant resources from constructed wetlands, the potential anti-metastatic effects of flavonoids from P. crispus, were investigated in human ovarian cancer cells ES-2. Two major flavonoids, luteolin-3’-O-p-D-glucopyranoside and flavone-6-C-β-D-glucopyranoside, were isolated from P. crispus and identified. The anti-metastatic effects of two flavonoids on cell proliferation, cell morphology, cell cycle, apoptosis, and cell migration and invasion were then investigated; reverse transcriptase polymerase chain reaction assays were also conducted to examine gene expression. Luteolin-3’-O-β-D-glucopyranoside inhibited ES-2 cell migration and invasion and suppressed the expression of two matrix metalloproteinases (MMPs), MMP-2and MMP-9, in vitro. Flavone-6-C-β-D-glucopyranoside had no significant inhibitory effects on ES-2 cells. The results demonstrated the potential anti-metastatic properties of a P. crispus flavonoids, and provided a scientific approach to the screening of promising natural resources from constructed wetlands for use in the pharmaceutical and Healthcare industries.In sum, the exploration of constructed wetland plant resource utilization of Nansi Lake was conducted in the perspective of anti-tumor natural products. Two typical wetland plant species were evaluated from several aspects to screen the antitumor activity and the separation and isolation technology pathway of activity constituents was established as well. This study suggested a novel perspective of constructed wetland plant resource utilization pattern of Nansi Lake basin, and the results of this study confirmed the feasibility of this new utilization pattern as well. |
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