Sevil Öksüz

Abietane diterpenoids and triterpenoic acids from Salvia cilicica and their antileishmanial activities

Bioguided-fractionation of an acetone extract of the roots of Salvia cilicica (Lamiaceae) led to isolation of two new diterpenes, 7-hydroxy-12-methoxy-20-nor-abieta-1,5(10),7,9,12-pentaen-6,14-dione and abieta-8,12-dien-11,14-dione (12-deoxy-royleanone), together with oleanolic acid, ursolic acid, ferruginol, inuroyoleanol and cryptanol. Their structures were determined spectroscopically, which included HREIMS and 2D NMR spectroscopic analysis. The new abietane derivatives showed appreciable in vitro antileishmanial activity against intracellular amastigote forms of both Leishmania donovani (IC(50) values of 170 and 120 nM, respectively) and Leishmania major (IC(50) values of 290 and 180 nM, respectively). The triterpenoic acids were found to be potently active against amastigote (IC(50) values of 7-120 nM) and moderately active against promastigote stages (IC(50) values of 51-137 nM) of the two Leishmania species.

Cytotoxic and antibacterial sesquiterpenes from Inula graveolens

Abstract A further study on the aerial parts of Inula graveolens afforded a new eudesmanolide, 11,13-dihydroivalin and four known sesquiterpene lactones, ivalin, inuviscolide, 8- epi -inuviscolide, 8- epi -xanthatin-1β,5β-epoxide, in addition to the previously isolated compounds. The structures were established by spectral methods and the compounds were evaluated for their cytotoxic and antibacterial activity.

Four diterpene esters from Euphorbia myrsinites.

The Turkish species Euphorbia myrsinites has yielded four new tetracyclic diterpene tetraesters from a cytotoxic acetone extract, in addition to the known cycloartane-type triterpenoids and betulin. The new compounds and their hydrolysis product have been extensively characterized by high field spectroscopic techniques, and were shown to be four new tetraesters of the parent alcohol, myrsinol.

Sesquiterpene acids from Inula Viscosa

Abstract In addition to known terpenoids and flavonoids two new sesquiterpene acids, viscic acid and viscosic acid, were obtained from the aerial parts of Inula viscosa.

Sesquiterpenoids and other constituents from Tanacetum cilicium.

Abstract The aerial parts of Tanacetum cilicium afforded five new closely related guaianolides; tanciloide, isotanciloide, tanciloide 8α-methylbutyrate, canin 8α-isovalerate, canin 8α-methylbutyrate and one new secoguaianolide, in addition to known compounds. The structures were elucidated by high field 1 H NMR spectroscopy.

Potent tyrosinase inhibitors from Trifolium balansae

Trifolium balansae (Leguminosae) yielded a phytylester, phytyl-1-hexanoate, three steroids, stigmast-5-ene-3β,26-diol, stigmast-5-ene-3-ol and campesterol, and an alcohol, pentacosanol which were reported for the first time from T. balansae. The structures of the isolates were determined by 1D and 2D NMR techniques and MS spectroscopy. Compounds 1–5 were tested for their enzyme tyrosinase activity. While compounds 1 and 5 did not show any inhibition against the enzyme tyrosinase, compounds 2, 3, and 4 exhibited potent inhibition against tyrosinase. Highly potent (IC50 = 2.39 μM) inhibition was found by compound 2, when compared with the standard tyrosinase inhibitors Kojic acid and L-mimosine.

Triterpenes of Centaurea ptosimopappoides

The roots of Centaurea ptosimopappoides afforded two new triterpenes; a new hopane derivative, 17β,21β-epoxy-16α-ethoxyhopan-3β-ol and a new baccharane type triterpene, 3β-acetoxy-17,24-dioxobaccharane. The known compounds, 17β,21β-epoxyhopan-3β-ol, 3β-acetoxyhop-17(21)-ene and 3β-acetoxy-erythrodiol were also isolated. In addition, the aerial parts yielded scopoletin, 7-oxositosterol, stigmasterol, α-amyrin and common sesquiterpene lactones of the genus Centaurea, 11,13-dihydro-desacetylcynaropicrin and cynaropicrin. The structures of the new compounds were determined by high field spectroscopic methods including 2D NMR techniques.

Guaianolides from Centaurea kotschyi

Abstract The aerial parts of Centaurea kotschyi (var. kotschyi ) afforded, besides three known sesquiterpene lactones, a new derivative of linichlorin B.

A guaianolide from Centaurea behen

Abstract Five sesquiterpene lactones of the guaianolide type were isolated from the leaves of Centaurea behen . One was identified as a new derivative of solstitialin A. The same extract also yielded a methylated flavone, circimaritin.

A sesquiterpene lactone from Achillea millefolium subsp. Millefolium

Abstract Aerial parts of Achillea millefolium subsp. millefolium yielded a new sesquiterpene lactone, achillifolin, together with known sesquiterpene lactones, dihydroparthenolide and dihydroreynosin. Known flavonoids, terpenoids and vanilic acid were also isolated.