Cafestol from green coffee beans

The chemistry of atractyloside has been reviewed. A further relative (87) of cafestol has been isolated from green coffee beans. Sideritis (Labiatae) species have continued to attract attention as a source of diterpenoids. The comparative phytochemistry of Canary Island species has been reviewed. A number of 15-hydroxykaurenes (88)—(90) have been isolated from S. crispata, S. ilicifolia, and S. tragoriganum together with the atisine (91) and beyerene (92) derivatives, ent-18-Acetoxy-3/8,7a,15/S-trihydroxykaur-16-ene has also been obtained from S. scardica. 

The furanoids, kahweol and cafestol, isolated from green coffee beans (4) have been found to induce increased GST activity and inhibit 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary tumor formation (9) and hamster cheek pouch carcinogenesis (10,11). The presence of the fiiran moiety was determined to be essential for enzyme induction. When the furan ring in cafestol was saturated by hydrogenation, its activity as a GST enzyme inducer was lost (S). 

Many diterpenoid alcohols are cyclic compounds occurring as free substances, but also as fatty acid esters or glycosides. The toxicity of latex of many plant species from the spurge family (Euphorbiaceae) is caused by the presence of phorbol esters such as 13-acetyl-12-myristoyl-phorbol. Cafestol, kahweol (8-25) and related diterpenoids (16-O-methylcafestol, 16-0-methylkahweol and other compounds) are found in green coffee Coffea spp., Rubiaceae) beans (mainly esterified to fatty acids at the C-16 or C-17 position) and unfiltered coffee prepared from roasted coffee seeds, such as Turkish coffee. Kahweol is specific to C. arabica coffee, where it occurs in concentrations of about 5890 mg/kg of fresh weight and 5200 mg/kg in the endosperm and perisperm, respectively, while 16-O-methylcafestol occurs only in robusta coffee (C. canephora). The amount of cafestol in C. arabica is about... 

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