Synthesis and Structure-Activity Relationships of Phaffiaol and Related Antioxidants.
作者:Shuji JINNO、Takaaki OKITA
DOI:10.1248/cpb.46.1688
日期:——
Total synthesis of a novel long chain alkyl phenol, phaffiaol (1), a potent antioxidant isolated from Phaffia rhodozyma, was achieved via three reaction steps starting from 3, 5-dibromosalicylaldehyde (2). We also prepared several types of long chain alkyl phenol having different aromatic rings or different carbon length, and evaluated their antioxidative activity using the rabbit erythrocyte membrane ghost system. Amongst these compounds, the novel methoxy phenol derivatives (6c, d, 7) having a heptadecyl moiety at the ortho-position to the hydroxy group, were approximately 2 times more active than α-tocopherol. In addition, 4-methoxy-2-pentadexylphenol (10h), which has a 15-carbon length in the side chain moiety, showed the maximum activity.
The large tendency of catechol rings to adsorb on surfaces has been studied by STM experiments with molecular resolution combined with molecular‐dynamics simulations. The strong adhesion is due to interactions with the surface and solvent effects. Moreover, the thermodynamic control over the differential adsorption of 1 and the nonanoic solvent molecules has been used to induce a new temperature‐induced
Novel Cytotoxic, Alkylated Hydroquinones from <i>Lannea welwitschii</i>
作者:Amiram Groweiss、John H. Cardellina、Lewis K. Pannell、Duangchan Uyakul、Yoel Kashman、Michael R. Boyd
DOI:10.1021/np960435t
日期:1997.2.1
Two novel natural products, lanneaquinol (1) and 2'(R)-hydroxylanneaquinol (2), were isolated from the organic extract of the plant Lannea welwitschii (Hiern) Engl. Their structures were solved by spectroanalytical methods and confirmed by comparison to synthetic models. The absolute configuration of 2 was determined by the modified Mosher method. Both compounds exhibited modest cytotoxicity against