A compound having the formula: ##STR1## wherein R.sup.1 is a straight chain, branched chain or cyclic lower alkyl group which may be substituted by a carboxyl group, and each of R.sup.2 and R.sup.3 which may be the same or different, is a hydrogen atom, a hydroxyl group, a methoxy group or an acetoxy group, and R.sup.4 is a hydroxyl group, a methoxy group or an acetoxy group; or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.
一种化合物的
化学式为:##STR1## 其中R.sup.1是一种直链、支链或环状低烷基,可以被羧基取代;R.sup.2和R.sup.3各自可以相同或不同,是氢原子、羟基、甲氧基或乙酰氧基;R.sup.4是羟基、甲氧基或乙酰氧基;或其药学上可接受的盐、生理
水解酯或溶剂化物。