Aim Isolation and structural elucidation of the constituents from the dried flower buds of Magnolia biondii Pamp. Methods Column chromatography and TLC were used to isolate chemical constituents. Spectroscopic methods...Aim Isolation and structural elucidation of the constituents from the dried flower buds of Magnolia biondii Pamp. Methods Column chromatography and TLC were used to isolate chemical constituents. Spectroscopic methods were employed for structural elucidation. Results One benzo furanoid neolignan （licarin B） and two bisepoxy lignans （magnolin, fargesin） were isolated and identified. Conclusion Licarin B is the first reported benzofuranoid lignan from the family Magnoliaceae.展开更多
Five caffeoyl conjugates were isolated from the ethyl acetate soluble fraction of Erigeron breviscapus (Van.) Hand_Mazz for the first time. Along with them, nine other chemical constituents were also identified. O...Five caffeoyl conjugates were isolated from the ethyl acetate soluble fraction of Erigeron breviscapus (Van.) Hand_Mazz for the first time. Along with them, nine other chemical constituents were also identified. One new caffeoyl conjugate, erigoster A (1) with a novel basic skeleton was mainly assigned by the using a combination of two_dimensional NMR techniques.展开更多
Every developing country has to meet the challenge of overcoming a condition of subalterrnity. After the victory of the Revolution in 1959, Cuba tackled this challenge in a very original way, prioritizing the developm...Every developing country has to meet the challenge of overcoming a condition of subalterrnity. After the victory of the Revolution in 1959, Cuba tackled this challenge in a very original way, prioritizing the development of scientific and technical know-how and of an advanced scientific system. Moreover, it pursued this goal with an extremely open attitude, using characteristic Cuban resourcefulness while at the same time taking advantage of every possible support and collaboration. While the country was increasingly integrated into the Soviet system and the Council for Mutual Economic Assistance （COMECON）, and therefore benefited from a close collaboration with the Soviet Union and the Eastern European countries＇ higher education and scientific systems, nevertheless it constantly sought collaboration with scientists and institutions in other countries as well, in particular in the Western world. The most meaningful instance of this collaboration is the development since the 1980s of an advanced biotechnological and biomedical system, which was created independently by the Soviet Union. Quite remarkably, when the socialist system collapsed, though Cuba faced a critical situation, the strategic choice was made not to cut support to this scientific sector, but rather to reinforce it. At present Cuba produces and exports advanced and in some cases unique vaccines and drugs, and this sector ranks as third in the country＇s source of current hard currency.展开更多
文摘Aim Isolation and structural elucidation of the constituents from the dried flower buds of Magnolia biondii Pamp. Methods Column chromatography and TLC were used to isolate chemical constituents. Spectroscopic methods were employed for structural elucidation. Results One benzo furanoid neolignan （licarin B） and two bisepoxy lignans （magnolin, fargesin） were isolated and identified. Conclusion Licarin B is the first reported benzofuranoid lignan from the family Magnoliaceae.
文摘Five caffeoyl conjugates were isolated from the ethyl acetate soluble fraction of Erigeron breviscapus (Van.) Hand_Mazz for the first time. Along with them, nine other chemical constituents were also identified. One new caffeoyl conjugate, erigoster A (1) with a novel basic skeleton was mainly assigned by the using a combination of two_dimensional NMR techniques.
文摘Every developing country has to meet the challenge of overcoming a condition of subalterrnity. After the victory of the Revolution in 1959, Cuba tackled this challenge in a very original way, prioritizing the development of scientific and technical know-how and of an advanced scientific system. Moreover, it pursued this goal with an extremely open attitude, using characteristic Cuban resourcefulness while at the same time taking advantage of every possible support and collaboration. While the country was increasingly integrated into the Soviet system and the Council for Mutual Economic Assistance （COMECON）, and therefore benefited from a close collaboration with the Soviet Union and the Eastern European countries＇ higher education and scientific systems, nevertheless it constantly sought collaboration with scientists and institutions in other countries as well, in particular in the Western world. The most meaningful instance of this collaboration is the development since the 1980s of an advanced biotechnological and biomedical system, which was created independently by the Soviet Union. Quite remarkably, when the socialist system collapsed, though Cuba faced a critical situation, the strategic choice was made not to cut support to this scientific sector, but rather to reinforce it. At present Cuba produces and exports advanced and in some cases unique vaccines and drugs, and this sector ranks as third in the country＇s source of current hard currency.
