Further Insight into Polycyclization Cascades of Acyclic Geranylfarnesol and its Acetate by Squalene-hopene Cyclase from Alicyclobacillus acidocaldarius.

The enzymatic reactions of geranylfarnesol (8) and its acetate 9, classified as sesterterpenes (C25), using squalene-hopene cyclase (SHC) were investigated. The enzymatic reaction of 8 afforded 6/6-fused bicyclic 20, 6/6/6-fused tricyclic 21, and 6/6/6/6-fused tetracyclic compounds 22 and 23 as the main products (35% yield), whereas that of 9 afforded two 6/6/6-fused tricyclic compounds 24 and 25 in a high yield (76.3%) and a small amount (5.0%) of 26 (the acetate of 22). A significantly higher conversion of 9 indicates that the arrangement of the substrate in the reaction cavity changed. The lipophilic nature and/or the bulkiness of the acetyl group may have changed its binding with SHC, thus placing the terminal double bond of 9 in the vicinity of the DXDD motif of SHC, which is responsible for the proton attack on the double bond to initiate the polycyclization reaction. The results obtained for 8 are different to some extent than those reported by Shinozaki et al. The products obtained in this study were deprotonated compounds; however, the products reported by Shinozaki et al. were hydroxylated compounds.

[Gastroprotective properties of gefarnate analogs with oxygen atoms in alcohol chain].

We assessed the effects of some gefarnate analogs on gastric ulcer prophylaxis (adrenaline ulcers) and ulcer healing (acetic ulcers) and some secretory parameters in rats. Acute ulcers were induced in male Wistar rats by intraperitoneal injection of 2 mg/kg adrenaline hydrochloride. Rats were killed after 24 hours. Chronic gastric ulcers were induced in rats by application of 100% acetic acid to the serosal surface of the stomach on 60 sec. Gefarnate analogs introduced intraperitoneally or intragastrically. Gefarnate analogs dose-dependently increase the healing of gastric ulcers and have a marked prophylaxis effects especially in the case of adrenaline ulcers.

Acyclic and incompletely cyclized triterpene alcohols in the seed oils of theaceae and gramineae.

The triterpene alcohol constituents of the non-saponifiable lipids of two Theaceae seed oils, sasanqua and camellia oils, and two Gramineae seed oils, wheat germ and rice bran oils, were investigated. This led to the isolation and characterization of one acyclic and eight incompletely cyclized triterpene alcohols. They are camelliol A, camelliol B, camelliol C, achilleol A, helianol, isohelianol, sasanquol, graminol A [(13R, 14R)-3,4-seco-25(10->9)abeo-8alpha,9beta,10al phapodioda-4,17,21 -trien-3-ol], and (2Z,6Z,10Z,14E,18E)-farnesyl-farnesol. Two other compounds isolated were characterized as (2Z,6Z,10E,14E)-geranylfarnesol, a sesterterpene alcohol, and phytol, a diterpene alcohol. Graminol A and (2Z,6Z,10E,14E)-geranylfarnesol are considered to be new natural products.