Isolation And Characterization Of Allelochemicals From Chlorophyta Ulva Pertusa

There are tight relations and complicated reciprocities in marine ecosystem. The research, which on the function and structure of the marine allelochemicals, has becoming a hot topic in marine chemical ecology. The allelochemicals could inhibit the growth of other species and accelerate the growth of biology which release the allelochemicals . As an elementary producer in food chain, algae was preyed on by animals and microbe. In order to capture space and ensure multiply, algae could produce the allelochemicals.Ulva pertusa, a kind of marine macroalgae, is a preponderant algae in Chinese sea area. The research in prophase has showed that Ulva pertusa has allelopathic effects on red microalgae. Based on former studies, allelochemicals were screened, isolated and identified from Ulva pertusa, and their allelopathic effects were evaluated also.From the extracts, 18 compounds were isolated by column chromatogram on silica gel VLC, Sephadex LH-20 and RP-18, followed by reverse-phase HPLC and recrystalization. Among them, 12 structures of the compounds were elucidated by use of spectroscopic methods (UV, IR, NMR, MS) and according to the physicochemical properties: cholesterol(1), Ergosterol(2), fucosterol(3), ethyl 4-hydroxybenzoate(4), vanillin(5), uracil(6), adenine(7), guanosine(8), uridine(9), cyclo-(Ala-Val)(10), stearic acid(11), 9,12-octadecadienoic acid(12). Compound 2, 4, 6, 7, 8, 9 and 10 were firstly isolated from Ulva pertusa.The primary biological activities of the compounds were evaluated on the models of cell cytoclasis , brine shrimp and growth inhibition of red tide microalgae. The results showed that compounds 2, 8, 9, 11 and 12 have obvious cytoclasis in P388 cells; compound 5, 11 and 12 has death effects on brine shrimp.The allelochemicals in algae were discovered. It has made an academic and applied progress in the chemical ecology and biologic prevention and cure on red tide.