所有地质试样(沉积物、石油、煤等),不论年代和起源如何,都含有茉烷类的五环三萜。经结构测定,地质茉烷类中多数的骨架碳原子包括侧链不超过35。这在植物中是很少存在的(C_29 C_30)。在细菌中发现的细菌茉烷四醇是第一个具C_35的生物茉烷类,有与地质茉烷类相同的骨架。在微生物中,这类前体的广泛分布可以解释为什么地质菜烷类的普 All geological samples (sediments, petroleum, coal, etc.), regardless of age and origin, contain pentamantane pentacyclic triterpenes. Structurally, most of the backbone carbon atoms in the germane include no more than 35 side chains. This is rare in plants (C_29 C_30). The bacteria found in bacteria, jasmonetane, are the first biomastrins with C_35 and have the same backbone as the geosmins. In microorganisms, the widespread distribution of such precursors can explain why the camptothecins are common