Olean-11,13(18)-dien-3β,30-diol dihemiphthalate (3), which was derived from glycyrrhetinic acid (GA), has been reported to produce a potent of anti-inflammatory effect in in vivo assays. Using 3 as a lead compound, we attempted to synthesize some modified compounds which varied in the following; i) the position of a carboxyl group in the phthalate moiety, ii) the number of carboxyls attached to the benzoyl group, iii) conversion of benzene ring to another ring system, iv) the linkage form between the benzene ring and oleanene skeleton at position 3 and/or 30. These were screened for their inhibitory activity against interleukin-1β (IL-1β)-induced prostaglandin E2 (PGE2) production in normal human dermal fibroblasts (NHDF). Although conversion of the ortho-carboxyl group of 3 into the meta-position or the para-position led to an increase in inhibitory activity, the elimination or increase of the carboxyl group resulted in loss of the inhibitory activity. Conversion of the ester bond to the amide bond at position 3 and/or 30 of 3 did not contribute to a significant increase in inhibitory activity. On the other hand, among the derivatives possessing an anthranilic acid moiety at position 30 of 3β-O-acetyl-olean-11,13(18)-dien-30-oic acid (20), 3β-hydroxy-30-nor-olean-11,13(18)-dien-20β-[N-(2-carboxyphenyl)]carboxamide (30) showed the most potent inhibitory activity (IC50 1.0 μM) in this series.
由
甘草次酸(GA)衍生得到的olean-11,13(18)-二烯-3β,30
-二醇二半
琥珀酸酯(3),已被报道在体内实验中表现出强效的抗炎作用。基于3作为先导化合物,我们试图合成一些结构修饰的化合物,它们在以下方面有所不同:i)
邻苯二甲酸部分中羧基的位置,ii)连接到苯甲酰基团的羧基数目,iii)将苯环转换为另一种环系,iv)苯环与氧化醇骨架在3和/或30位置的连接形式。这些化合物被筛选其抑制正常人皮肤成纤维细胞(NHDF)中白介素-1β(IL-1β)诱导的
前列腺素E2(
PGE2)产生的活性。尽管将3的邻羧基组转换为间位或对位位置增加了抑制活性,但消除或增加羧基组导致抑制活性丧失。将3的3和/或30位置的酯键转换为酰胺键并没有显著增加抑制活性。另一方面,在3β-O-乙酰基-氧化醇-11,13(18)-二烯-30-
羧酸(20)的30位置含有
邻氨基苯甲酸部分的衍
生物中,3β-羟基-30-去氧化醇-11,13(18)-二烯-20β-[N-(2-羧基苯基)]羧酰胺(30)显示出这一系列中最强的抑制活性(IC50 1.0 μM)。