Quinic acids from Aster caucasicus and from transgenic callus expressing a beta-amyrin synthase.

Several different classes of secondary metabolites, including flavonoids, triterpenoid saponins and quinic acid derivatives, are found in Aster spp. (Fam. Asteraceae). Several Aster compounds revealed biological as well as pharmacological activities. In this work, a phytochemical investigation of A. caucasicus evidenced the presence of quinic acid derivatives, as well as the absence of triterpene saponins. To combine in one species the production of different phytochemicals, including triterpenes, an Agrobacterium-mediated transformation of A. caucasicus was set up to introduce A. sedifolius β-amyrin synthase (AsOXA1)-encoding gene under the control of the constitutive promoter CaMV35S. The quali-quantitative analysis of transgenic calli with ectopic expression of AsOXA1 showed, in one sample, a negligible amount of triterpene saponins combined with higher amount of quinic acid derivatives as compared with the wild type callus

Anti-angiogenic activity evaluation of secondary metabolites from Calycolpus moritzianus leaves.

Angiogenesis is a crucial step in many pathological conditions like cancer, inflammation and metastasis formation; on these basis the search for antiangiogenic agents has widened. In order to identify new compounds able to interfere in the Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1, also known as Flt-1) recognition by VEGFs family members, we screened Calycolpus moritzianus (O. Berg) Burret leaves extracts by a competitive ELISA-based assay. MeOH and CHCl3 extracts and several their fractions demonstrated to be able to prevent VEGF or PlGF interaction with Flt-1, with an inhibition about 50% at concentration of 100 μg/mL. Phytochemical and pharmacological investigation of the active fractions led to the isolation of flavonoids, and terpenes

Impact of ploidy change on secondary metabolites and photochemical efficiency in Solanum bulbocastanum.

Plants are well known for producing a wide diversity of natural compounds and several strategies have been proposed to enhance their production. Among them, somatic chromosome doubling may represent an effective and inexpensive method. The objective of the current study was to investigate the effect of polyploidization on the leaf metabolic profile and content of tetraploids produced from a wild diploid (2n=2x=24) potato species, Solanum bulbocastanum Dun. Photochemical efficiency of tetraploids was also analyzed. Results from HPLC-DAD and LC/MS analyses provided evidence that tetraploid genotypes displayed either a similar or a lower phenylpropanoids, tryptophan, tyrosine and α-chaconine content compared with the diploid parent. Similarly, no significant differences were found among genotypes both for measures of gas and for chlorophyll fluorescence, except for non-photochemical quenching (NPQ). Steroidal saponins content revealed superiority of some tetraploids with respect to the diploid parent, suggesting perturbations in the mechanism regulating the biosynthesis of such compounds following polyploidization. Lack of superiority may be attributed to the time required for adjustment, adaptation and evolution after the genomic shock induced by polyploidization, as well as the fact that an optimum ploidy level for each species may be crucial. Our results suggest that polyploidization as a strategy to enhance metabolite production cannot be generalized

A new glucosidic iridoid from Isodon rubescens

One new glucosidic iridoid, 6-O-veratroylbarlerin, was isolated from the chloroform/methanol extractof Isodon rubescens (Hemsl.) H.Hara, Lamiaceae aerial parts, along with the known compounds apigeninand caffeic acid. The structure of the new compound was elucidated on the basis of 1D and 2D NMRexperiments and ESI-MS technique

Enhanced biosynthesis of bioactive abietane diterpenes by overexpressing AtDXS or AtDXR genes in Salvia sclarea hairy roots

Diterpenoids are important compounds for plant survival and have beneficial properties for humans. Bioactive abietanic diterpenes are synthesized in roots of Salvia sclarea (e.g. aethiopinone, 1-oxoaethiopinone, salvipisone, and ferruginol), but at a very low level (about 1 % of root dry weight). To enhance the biosynthesis of this interesting class of compounds, heterologous AtDXS (d-xylulose 5-phosphate synthase) or AtDXR (1-deoxy-d-xylulose 5 phosphate reductoisomerase) genes, encoding the up-stream enzymes of the plastidial 2-C-methyl-D-erythritol 4-phosphate (MEP)-dependent terpenoid pathway, were ectopically expressed in S. sclarea hairy roots. Quantitative targeted metabolic analysis (HPLC–DAD) revealed that three independent root lines, expressing different levels of DXS or DXR transcripts and proteins, synthesized a significant higher content of abietanic diterpenes, compared to the control hairy root line transformed with the empty vector. The increase was gene-dependent, since the overexpression of the AtDXR triggered a 4.4-fold increase in aethiopinone, an abietane quinone-type tricyclic diterpene. In addition, aethiopinone was proved to be cytotoxic to different solid tumor cell lines, with the highest effect on human melanoma A375 cell line (IC50 11.4 µM). Overall these results show that it is possible to boost the metabolic flow towards the synthesis of abietanic diterpenes in S. sclarea hairy roots by overexpressing genes involved in the first steps of the MEP-pathway and provide new insights for the large-scale production of this class of compounds, with potential application in cancer treatment

A Novel Tirucallane-type Triterpene and Sesquiterpene from Trichilia maynasiana

One new tirucallane-type triterpene 3β, 24-dihydroxytirucallan-7,25-diene, 24-sulfate (1), one new sesquiterpene 7-epi-10-hydroxychabrol-1(2)-en-4,5-dione A (2), together with three known tirucallanes, and four aromadendranes were isolated from the leaves of Trichilia maynasiana C. DC.. Their structures were determined by means of NMR spectroscopy, mass spectrometric analysis, and chemical methods

Phenolic compounds from clinopodium tomentosum (Kunth) govaerts (Lamiaceae)

Phytochemical investigation of the leaf extracts of Clinopodium tomentosum (Kunth) Govaerts (Lamiaceae) allowed the isolation of one new compound, named 2-O-benzoyl-3-O-cinnamoyl tartaric acid, along with twelve known compounds, dihydrodehydroconiferyl alcohol 9'-O-β-D-glucopyranoside, blumenol c glucoside, syringaresinol 4'-O-β-D-glucopyranoside, hesperetin, pinocembrin 7-O-rutinoside, clinopodic acid E, caffeic acid, p-coumaric acid, caffeic acid methyl ester, caffeic acid ethyl ester, rosmarinic acid, and rosmarinic acid methyl ester. Their structural characterization was obtained on the basis of extensive spectroscopic analyses, including mono- and bidimensional nuclear magnetic resonance (1D and 2D NMR) experiments and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS)