L-Ascorbic acid（AA,vitamin C） exhibits a high concentration in the brain.The transportation of AA in brain is mainly mediated by the glucose transporter 1（GLUT1） and the Na+-dependent vitamin C transporter SVCT2.While L-ascorbic acid C6-O conjugation has been investigated as a tool to enhance brain drug delivery,C5-O conjugation and C5-O & C6-O conjugation as brain targeting tools have not been reported.In this letter,ibuprofen was linked directly to C5-O,C6-O and C5-O & C6-O positions of L-ascorbic acid with eater bonds,providing prodrug 1,2 and 3,respectively,to improve their targeting abilities in the brain.Prodrug 1,2 and 3 were synthesized in facile ways with good yields.And the preliminary evaluation in vivo illustrated that prodrug 2 had a better targeting ability than prodrug 1. Moreover,prodrug 3,whose C5-O & C6-O positions were both modified,had good targeting ability for brain which will provide an important evidence for our further study on C5-0- & C6-0- di-derivatives of L-ascorbic acid.
Oleanolic acid 1 exists widely in food,medicinal herbs and other plants and possesses many attractive biological activities. Recently,some oleanolic derivatives were reported to have interesting anti-tumor activities.Herein,using association principle of drug design,OA disaccharide 17 was designed and synthesized by coupling a-L-rhamnopyranosyl-(1→2)-a-L-arabinopyranosyl disaccharide moiety,which has proved to be a unique sugar sequence with strongly antitumor activity,and modified OA with a nitrile at C-17.
Shu Chen PeiJian Bo WuFan LeiShan QianLi HaiYong Wu
A series of l-oxacephem analogs were synthesized and their antibacterial properties against five strains of Gram-positive and Gram-negative bacteria were evaluated in vitro while ceftazidine was selected as control. Some of the tested compounds, compound 2c in narticular,showed more active aeainst three selected strains than the standard.
