tailieunhanh - BIOLOGICALLY ACTIVE NATURAL PRODUCTS: AGROCHEMICALS - CHAPTER 4

Từ một cuộc khảo sát cho hoạt động allelopathic tiềm năng của một số 25 hydrophytes thân thảo có nguồn gốc từ Mỹ phía đông nam, chúng tôi tìm thấy hai loài trong Nymphaeceae để có các hoạt động ức chế lớn nhất. Nuphar lutea là loài hoạt động tích cực nhất và tích cực hơn khoảng 10 lần so với Nymphaea odorata, thứ hai hoạt động được đo bằng cây giống rau diếp và tăng trưởng Lemna xét nghiệm nhỏ. Sinh thử nghiệm hướng cô lập của các thành phần thực vật ức chế sự tăng trưởng từ N | 4 Phytochemical Inhibitors from the Nymphaeceae Nymphaea odorata and Nuphar lutea Stella D. Elakovich Stacy Spence and Jie Yang CONTENTS Introduction Nuphar lutea Nymphaea odorata Conclusions Acknowledgments References KEY WORDS Nymphaeceae Nymphaea odorata Nuphar lutea hydrophytes allelopathy growth inhibition alkaloids gallotannins. ABSTRACT From a survey for potential allelopathic activity of some 25 herbaceous hydrophytes native to the southeastern . we found two species in the Nymphaeceae to possess the greatest inhibitory activity. Nuphar lutea was the most active species and was some 10 times more active than Nymphaea odorata the second most active as measured by lettuce seedling and Lemna minor growth assays. Bioassay-directed isolation of plant growth inhibitory constituents from N. odorata led to the isolation of five allelochemicals of moderate activity. These included gallic acid myricitrin myricetin 1 2 3 4 6-pentagalloyl-D-glucose and 2 3 4 6-tetragalloyl-D-glucose. Examination of alkaloids from N. lutea showed 6 6 -dihydroxythiobinupharidine to be highly inhibitory of lettuce seedling radicle elongation at concentrations greater than 2 ppm. Nupharolutine a second alkaloid isolated that was of similar structure was inactive. Literature reports of phytochemicals present in N. odorata and N. lutea as well as in other members of the Nymphaeceae are examined. Introduction In our work in the area of allelopathy the influence of one plant on another we have been working with aquatic and wetland plants native to the southeast . We have examined more than 25 different aqueous extracts from these plants to determine their allelopathic The plant species examined are listed in Table . Species of Eleocharis were included as they often appear in monoculture in their undisturbed natural habitats and 1999 by CRC Press LLC TABLE Plants Native to the southeastern . Examined