Iclal Saracoglu

Cytotoxic and antioxidative activities of Plantago lagopus L. and characterization of its bioactive compounds

Bioactivity guided isolation and characterization of phytoconstituents from the aerial parts of Plantago lagopus L. were performed to give a new insight into the usage of Plantago species in traditional medicine. The extract showed strong radical scavenging effects against DPPH, nitric oxide (NO) and superoxide (SO) radicals comparable to that of known antioxidants 3-t-butyl-4-hydroxyanisole, ascorbic acid (vitamin C), and quercetin in addition to its cytotoxic activities against HEP-2 (human larynx epidermoid carcinoma) and RD (human rhabdomyosarcoma) cell lines based on MTT assay for growth inhibition. The gallic acid equivalent total phenolic content of the plant was found to be 79.94 mg/g dry extract. Phenylethanoid glycosides, verbascoside and calceorioside A were isolated from the most active fraction and both compounds showed strong radical scavenging activity against tested radicals and cytotoxicity against HEP-2, RD and MCF-7 (human breast adenocarcinoma) cell lines. In addition apoptotic cell death was observed in histological analysis. Taken together, these findings suggest that verbascoside and calceorioside A may be used in cancer prevention.

Effects of phenylpropanoid and iridoid glycosides on free radical-induced impairment of endothelium-dependent relaxation in rat aortic rings

The protective effect of phenylpropanoid glycosides, forsythoside B and alyssonoside, and the iridoid glycoside lamiide, isolated from the aerial parts of Phlomis pungens var. pungens, against free radical-induced impairment of endothelium-dependent relaxation in isolated rat aorta was investigated. Aortic rings were exposed to free radicals by the electrolysis of the physiological bathing solution. Free radical-induced inhibition of the endothelium-dependent relaxation in response to acetylcholine was countered by incubation of the aortic rings before electrolysis with the aqueous extract (200 microg/ml), phenylpropanoid fraction (100 microg/ml) and iridoid fraction (150 microg/ml) of P. pungens var. pungens. Major components of the phenylpropanoid fraction forsythoside B and alyssonoside also prevented the inhibition of the acetylcholine response, at 10(-4) M concentration. However, the major component of iridoid fraction lamiide was found ineffective at the same concentration. The protective activity of phenylpropanoid glycosides against the free radical-induced impairment of endothelium-dependent relaxation may be related to their free radical scavenging property.

Phlinosides A, B and C, three phenylpropanoid glycosides from Phlomis linearis.

Three new phenylpropanoid glycosides, phlinosides A, B and C were isolated from a methanolic extract of the aerial parts of Phlomis linearis. On the basis of chemical and spectral evidence their structures were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-glucopyranosyl-(1----2)-a lpha-L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, 3,4 dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-alpha- L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha- L-rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, respectively.

Phlinosides D and E, phenylpropanoid glycosides, and iridoids from Phlomis linearis

Two new phenylpropanoid glycosides, phlinosides D and E were isolated from the methanolic extract of the aerial parts of Phlomis linearis, along with the known iridoid glucosides, lamiide, ipolamiide and auroside (= 5-hydroxy-8-epiloganin). On the basis of chemical and spectral evidence the structures of phlinosides D and E were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-al pha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside, respectively.

Two phenethyl alcohol glycosides from Scutellaria orientalis subsp. Pinnatifida

Two new phenethyl alcohol glycosides, darendoside A and B (= deacyl martynoside) were isolated from the methanolic extract of the aerial parts of Scutellaria orientalis subsp. pinnatifida, along with four known glycosides, syringin, martynoside, leucosceptoside A and verbascoside. On the basis of chemical and spectral evidence the structures of darendoside A and B were determined as beta-(4-hydroxyphenyl)ethyl O-beta-D-apiofuranosyl-(1-->2)-O-beta-D-glucopyranoside and beta-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-L-rhamnopyranosyl-(1-->3)-O-beta-D-glucopyranoside (= deacyl martynoside), respectively.

Iridoid content and biological activities of Veronica cuneifolia subsp. cuneifolia and V. cymbalaria

Context: The genus Veronica L. (Plantaginaceae) is represented by 79 species, 26 of which are endemic in Turkey. Some Veronica species are used for the treatment of different inflammatory diseases and cancer in traditional medicine. In addition, chemotaxonomy of the genus is important for the reclassification of the family Plantaginaceae after different phylogenetic studies. Objective: Veronica cuneifolia subsp. cuneifolia D. Don and V. cymbalaria Bodard were studied from the view point of iridoid glucosides which are known as chemotaxonomical markers for this genus. Radical scavenging and cytotoxic activities of the extracts were also determined in this study. Material and methods: Major compounds, isolated from iridoid fractions of V. cuneifolia subsp. cuneifolia were used as the standard compounds for HPLC after determination of their structures, and investigated for their presence in iridoid fractions of V. cymbalaria. Additionally, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and SO radical scavenging and cytotoxic activities against three cancer and a noncancerous cell lines of both extract were also tested using the MTT method. Results: While aucubin, catalpol, verproside, amphicoside, verminoside, and veronicoside were obtained from V. cuneifolia subsp. cuneifolia, two more iridoid glucosides, 6-O-veratroylcatalposide and 6-O-isovanilloylcatalpol, were isolated from V. cymbalaria. Comparing both species, V. cuneifolia subsp. cuneifolia showed stronger radical scavenging and cytotoxic activities than V. cymbalaria. Discussion: Our results demonstrated that the iridoid contents of both species were very close to each other confirming to the chemotaxonomic studies on Veronica species and their different bioactivity range make the plants interesting from the view point of natural drug discovery research.

Chlorinated Iridoid Glucosides from Veronica longifolia and Their Antioxidant Activity

From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely, asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol ester verproside (5a) or to catalpol (5), respectively. The configuration of the previously known vanilloyl analogue, urphoside B, was shown to be the 6β-epimer (6c) of the structure originally reported. Longifoliosides A (6a) and B (6b) were found to exhibit radical-scavenging activity against nitric oxide, superoxide, and 2,2-diphenyl-1-picrylhydrazyl radicals.

Iridoid glucosides from Veronica pectinata var. glandulosa

Abstract A new highly oxygenated iridoid glucoside, urphoside B (1) was isolated from the Veronica pectinata var. glandulosa together with seven known iridoid glucosides, aucubin, catalpol, veronicoside, catalposide, verproside, amphicoside and 6-O-veratroyl catalpol. The planar as well as the stereo structures of the isolated compounds were determined by means of extensive 1D- and 2D-NMR spectroscopy and confirmed by HR-Mass.

Neolignan Glucosides From Phlomis Chimerae Boiss

From the aerial parts of the plant Phlomis chimerae, a new neolignan glucoside, (-)-4-O-methyldihydrodehydrodiconiferyl alcohol-9′-O-β-ᴅ-glucopyranoside (1) was characterized along with the known neolignan glucosides, (D)-4-O-methyldehydrodiconiferyl alcohol-9′-O-β-ᴅ-glucopyranoside (= longifloroside A) (2) and (-)-dihydrodehydrodiconiferyl alcohol-9-O-β-ᴅ-glucopyranoside (3). The structure of the new compound was established on the basis of spectroscopic evidence

Phenylethanoid Glycosides from Phlomis integrifolia Hub.-Mor.

Abstract Two new phenylethanoid glycosides integrifoliosides A (2) and B (3), along with a known phenylethanoid glycoside alyssonoside (1) and a flavone glucoside chrysoeriol-7-O-β-ᴅ-glucopyranoside (4) were isolated from the aerial parts of Phlomis integrifolia. The structures of the new compounds were identified as 3,4-dihydroxy-β-phenylethoxy-O-β-ᴅ-apiofuranosyl- (1 →4)-α-ʟ-rhamnopyranosyl-(1 →3)-4-O-feruloyl-β-ᴅ-glucopyranoside (2) and 3-hydroxy-4-methoxy-β-phenylethoxy-O-β-ᴅ-apiofuranosyl-(154)-α-ʟ-rhamnopyranosyl-(1→3)-4-O-feruloyl-β-ᴅ-glucopyranoside (3), on the basis of spectroscopic (UV, IR, 1D- and 2D-NMR, and HR-FABMS) methods.