Biomedical subjects

F Pinar Sahin

Publications and source records attributed to F Pinar Sahin.

4 recordsLinked to original sources

PubMed2006

ent-7alpha,18-Hydroxykaur-16-ene ethanol solvate.

The ent-kaurene diterpene in the title compound, 7-epicandicandiol ethanol solvate, C20H32O2.C2H6O, was isolated from the aerial parts of Sideritis ozturkii Aytaç & Aksoy. The molecule has the usual conformation and stereochemistry found in related ent-kaurene derivatives. The methyl-substituted ring junction has a trans arrangement and the other junction is cis. The six-membered rings have chair or slightly distorted chair conformations and the five-membered ring has an envelope conformation. Intermolecular hydrogen bonds link the 7-epicandicandiol and ethanol molecules into two-dimensional networks, part of which comprise co-operative O-H...O-H...O-H... chains.

Crystallography, X-Ray↗

PubMed2004

Molecular cloning and characterization of a glucosyltransferase catalyzing glucosylation of curcumin in cultured Catharanthus roseus cells.

Catharanthus roseus cell suspension cultures are capable of converting exogenously supplied curcumin to various glucosides. The glucosylation efficiency is enhanced by addition of methyl jasmonate (MJ) to the cultures prior to curcumin administration. Two cDNAs encoding UDP-glucosyltransferases (CaUGT1 and CaUGT2) were isolated from a cDNA library of cultured C. roseus cells, using a PCR method directed at the conserved UDP-binding domain of plant glycosyltransferases. The sequence identity between their deduced amino acid sequences was 27%. The expression of both genes was up-regulated by addition of MJ to the cell cultures although the mRNA level of CaUGT1 was much lower than that of CaUGT2. The corresponding cDNAs were expressed in Escherichia coli as fusion proteins with maltose-binding protein. The recombinant CaUGT1 exhibited no glucosylation activity with either curcumin or curcumin monoglucoside as substrate, whereas the recombinant CaUGT2 catalyzed the formation of curcumin monoglucoside from curcumin and also conversion of curcumin monoglucoside to curcumin diglucoside. The use of the recombinant CaUGT2 may provide a useful new route for the production of curcumin glucosides.

Catalysis↗

PubMed2004

Three acylated flavone glycosides from Sideritis ozturkii Aytac & Aksoy.

From the aerial parts of Sideritis ozturkii, three new flavonoids, chrysoeriol 7-O-[2'''-O-caffeoyl-O-acetyl-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside], chrysoeriol 7-O[2'''-O-caffeoyl-beta-D-glucopyranosyl-(1 -->2)-beta-D-glucopyranoside] and chrysoeriol 7-O[2'''-O-p-coumaroyl-6'''-beta-O-acetyl-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside] named as ozturkosides A, B and C, respectively, were isolated, along with three known phenylethanoid glycosides, verbascoside, leucoseptoside A, martynoside and five known diterpenoids, 7-epicandicandiol, linearol, sidol, sideroxol, epoxyisolinearol. The structures were elucidated mainly by spectroscopic methods.

Chromatography, Liquid↗

PubMed2003

Molecular cloning and characterization of a cDNA encoding a novel apoplastic protein preferentially expressed in a shikonin-producing callus strain of Lithospermum erythrorhizon.

A cDNA (LEPS-2) encoding a novel cell wall protein was cloned from shikonin-producing callus tissues of Lithospermum erythrorhizon by differential display between a shikonin-producing culture strain and a non-producing strain. The LEPS-2 cDNA encoded a polypeptide of 184 amino acids. The deduced amino acid sequence exhibited no significant homology with known proteins. Expression of LEPS-2 gene as well as accumulation of LEPS-2 protein was highly correlated with shikonin production in L. erythrorhizon cells in culture. In the intact plant, expression of LEPS-2 was detected only in the roots where shikonin pigments accumulated. Cell fractionation experiments and immunocytochemical analysis showed that the protein was localized in the apoplast fraction of the cell walls. The shikonin pigments were also stored on the cell walls as oil droplets. These results indicate that expression of the LEPS-2 is closely linked with shikonin biosynthesis and the LEPS-2 protein may be involved in the intra-cell wall trapping of shikonin pigments.

Amino Acid Sequence↗