Triterpenoids of Cnidosculus urens

The ethanol extract of Cnidosculus urens yielded β-amyrin cinnamate and germanicol acetate. Also, using ¹³C NMR spectroscopy, mixtures of β-amyrin, germanicol and lupeol as well as their acetates were identified.     

Maculatin: An isomer of uvedalin epoxide from Polymnia maculata

The isolation of a new germacranolide, maculatin IIc or IId, from Polymnia maculata Cav. is reported.     

β-Citraurin epoxide,a new carotenoid from valencia orange peel

A new minor carotenoid, β-citraurin epoxide (3-hydroxy-5,6-epoxy-5,6-dihydro-8′-apo-β-caroten-8′-al) and several isomers of violaxanthin (5,6,5′,6′-diepoxy-5,6,5′,6′-tetrahydro-β,β-caroten-3,3′-diol) have been identified in Valencia orange peel. The previously reported occurrence of apo-10′-violaxanthal (3-hydroxy- 5,6-epoxy-5,6-dihydro-10′-apo-β-caroten-10′-al) and apo-12′-violaxanthal (3-hydroxy-5,6-epoxy-5,6-dihydro- 12′-apo-β-caroten-12′-al) has been confirmed, and their syntheses are described. The quantitative determination of the carotenoids has also been performed.     

A new sesquiterpene lactone from Elephantopus scaber

A methanolic extract of the plant Elephantopus scaber was found to contain lupeol, stigmasterol and a new germacranolide dilactone 11,13-dihydrodeoxyelephantopin.     

Irreversible protein binding of norethisterone (norethindrone) epoxide.

14,15-3H-Norethisterone-4 beta, 5 beta-epoxide, a metabolite of norethisterone, was incubated with several proteins and nucleic acids. After 30 min incubation 0.19 nmol of the epoxide were irreversibly bound per mg albumin which contains free sulfhydryl groups; proteins without SH-groups, such as concanavalin A, gamma-globulin, DNA and RNA, did not irreversibly bind norethisterone epoxide. A superoxide (O2) generating enzyme system comprised of xanthine oxidase and hypoxanthine was capable of catalyzing the irreversible binding of the parent compound, norethisterone, to albumin, indicating that an oxidation product was formed which reacted with the protein. When norethisterone epoxide was incubated for 60 min with hepatic microsomes of rats in absence of NADPH, about 2.0 nmol of the epoxide were irreversibly incorporated per mg microsomal protein. This binding was increased to 5.2 nmol by addition of a NADPH regenerating system. Addition of glutathione and cytosol decreased only the NADPH-dependent protein binding; phenobarbital pretreatment of rats induced this NADPH-dependent binding of norethisterone epoxide to microsomal protein by a factor of 2. In presence of NADPH, binding of the epoxide to microsomal protein depended on substrate concentration used. The results indicate that norethisterone epoxide is able to chemically react with proteins. In addition, hepatic microsomal enzymes convert the epoxide to another metabolite which also can react with proteins.     

Two new flavone glycosides from Cirsium lineare

An examination of four species of Cirsium disclosed the presence of two new flavonoids in C. lineare. The structure of one was 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (cirsilineol) 4′-monoglucoside and the other 5,3′,4′-trihydroxy-6,7-dimethoxyflavone (cirsiliol) 4′-monoglucoside. Luteolin 7-glucoside was found in C. suffultum, and pectolinarin and linarin in C. kamtschaticum and C. pectinellum.     

A new dihydrobenzofuran from Liatris provincialis

A chloroform extract of Liatris provincialis Godfrey gave as a minor component a new dihydrobenzofuran, whose structure was established as I.     

Latex extractables of Calotropis gigantea

The hexane and methanol soluble extract of the latex coagulum of Calotropis gigantea afforded two new triterpene esters, viz. 3′-methylbutanoates of α-amyrin and ψ-taraxasterol, besides the known 3′-methylbutanoates of three triterpene alcohols. The compositions of the alkane fraction, total triterpene alcohol fraction, and free, acetyl and 3′-methylbutanoyl triterpene alcohol fractions of the extract were determined.     

An acetylenic epoxide and a ferulate from Coreopsis longula

The aerial parts of Coreopsis longula gave, in addition to known compounds, a new acetylenic epoxide, hepta-deca-1,9E,15E-trien-11,13-diyn-7,8-epoxide, while the roots afforded a new ferulate, coniferyl ferulate.     

Diterpenes from Palafoxia texana

The investigation of Palafoxia texana afforded in addition to the known compound jesromotetrol two new rosene derivatives: 3β-acetoxy-jesromotetrol and 3β,19-diacetoxy-jesromotetrol. The structures were determined by spectroscopic methods and chemical transformations.