tailieunhanh - Chemical transformation of ent-kaurane-type diterpenoids from Croton tonkinensis Gagnep: I - Hydrolysis, Acetylation, and Oxidation of ent-18-acetoxy-7B-hydroxykaur-16-en-15-one

In our studies on the phytochemistry and biological activities of Croton tonkinensis Gagnep. (Euphorbiaceae) oriented by traditional medicine interesting biological activities of the plant were demonstrated in correlation with the ent-kaurane-type diterpenoid constituents. The high accumulation of the active principle ent-18-acetoxy-7 -hydroxykaur-16-en-15-one (1) led to our recent study on the chemical modification of this lead compound. In this paper the transformations of 1 into several derivatives by hydrolysis, acetylation, and oxydation were reported. The cytotoxic activity against of the transformation products Hep-G2 and LU cells was evaluated | Journal of Chemistry Vol. 45 3 P. 382 - 385 2007 CHEMICAL TRANSFORMATION OF ENT-KAURANE-TyPE DITERPENOIDS FROM CRQTQN TQNKINENSIS GAGNEP. I - HyDROLySIS ACETyLATION AND OXIDATION OF ENT-18-ACETOXy-7p-HyDROXyKAUR-16-EN-15-ONE Received 28 August 2006 PHAN MINH GIANG LE THI HONG DƯNG PHAN TONG SON Laboratory of Chemistry of Natural Products Faculty of Chemistry College of Natural Science Vietnam National University Hanoi Vietnam SUMMARY In our studies on the phytochemistry and biological activities of Croton tonkinensis Gagnep. Euphorbiaceae oriented by traditional medicine interesting biological activities of the plant were demonstrated in correlation with the ent-kaurane-type diterpenoid constituents. The high accumulation of the active principle ent-18-acetoxy-7f-hydroxykaur-16-en-15-one 1 led to our recent study on the chemical modification of this lead compound. In this paper the transformations of 1 into several derivatives by hydrolysis acetylation and oxydation were reported. The cytotoxic activity against of the transformation products Hep-G2 and LU cells was evaluated. Keywords Croton tonkinensis Euphorbiaceae ent-kaurane-type diterpenoid chemical transformation cytotoxicity I - INTRODUCTION Croton tonkinensis Gagnep. Euphorbiaceae is a small plant of 1 - 2 m high and known in Vietnamese as Kho sam Bac Bo or Kho sam cho la 1 - 3 . The plant occurs widely and also cultivated as a medicinal plant in northern Vietnam. Its dried leaves Folium Tonkinensis have been used in Vietnamese traditional medicine to treat boils abscesses impetigo abdominal pain dyspepsia dysentry gastric and duodenal ulcers. Moreover it is a component of recipes applied to cure urticaria leprosy psoriasis vaginitis due to trichomonas and genital organs prolapse. The studies on phytochemistry and biological activities of C. tonkinensis were oriented by traditional medicine. The anti-inflammatory activity of the 382 plant was assessed using the nuclear factor kappa B NF-kB reporter gene .