Zerumbone 8,9-epoxide

Zingiber zerumbet Smith Qiu Jiang (Ginger) (rhizome)55-60 3".4"-0-diacetylafzelin, zerumbone, zerumbone epoxide, curcuminoids diferuloylmethane, feruloyl-p-coumaroylmethane, di-p-coumaroylmethane, essential oils, alpha-humulene.192-193-195 These compounds are cytotoxic. A tonic, stimulant, depurative, to treat asthma, stomachache, antimicrobial properties. This plant plays an important role in masculine rituals and it makes women sterile. 

The same substrate was incubated in A. niger, Aspergillus oryzae, Candida rugosa, Candida tropicalis, Mucor mucedo, Bacillus subtilis, and Schizosaccharomyces pombei however, any metabolites have been obtained. All microbes except for the last organism, zerumbone epoxide (409), prepared by mCPBA, bioconverted into two diastereoisomers, 27 ,65,75-dihydro- (411) and 2/ ,6/ ,7/ -derivative (412), whose ratio was determined by GC, and their enantio-excess was over 99% (Nishida and Kawai, 2007) (Figure 20.119). 

Formic acid catalyzed transannulation of the 8,9-epoxide (163), derived from natural zerumbone, has been shown to lead to a mixture of the bicyclo[6.3.0]undecane (164) and the hydroazulene (165 equation 72). 

Direct methods of converting humulene (332) into its 8,9-monoepoxide (337)t and into zerumbone (338) have proved to be very inefficient. Shirahama et al. have now brought about these conversions by indirect means. Thus, for the epoxide (337),169 humulene is first transformed to the acetate (339) by treatment with boron trifluoride etherate in glacial acetic acid followed by mono-epoxidation. Reduction of this acetate with LiAlH, followed by elimination with mesyl chloride in pyridine gives the epoxide (337). In the case of zerumbone (338),170 the readily... 

Alkaline Hydrogen Peroxide. ajS-Unsaturated ketones (123) were epoxidized with alkaline hydrogen peroxide to form 4/5,5/ -epoxyandrostane-6,17-diones (124). The presence of a 3j -hydroxy-group was found to be advantageous during epoxidation. Initial attempts to epoxidize zerumbone (125)... 

Humulenes (167) and (168), which were detected in various oils, presumably do not play an essential role in hop oil [odor threshold in water solution 120 ppb (71)]. Oxygen-containing humulene derivatives, among which epoxides (169) and (170) (77), humulol (174) (428) and ketones (176) and (177) (429) were identified, might contribute much to the hop character imparted to hop beverages (71). All these substances (167) to (173) as well as zerumbone (175) were first isolated from the essential oil of wild ginger (99, 100, 101). 

---