Centranthus ruber (L.) DC. and Tropaeolum majus L.: Phytochemical Profile, In Vitro Anti-Denaturation Effects and Lipase Inhibitory Activity of Two Ornamental Plants Traditionally Used as Herbal Remedies.

Ornamental plants often gain relevance not only for their decorative use, but also as a source of phytochemicals with interesting healing properties. Herein, spontaneous Centranthus ruber (L.) DC. and Tropaeolum majus L., mainly used as ornamental species but also traditionally consumed and used in popular medicine, were investigated. The aerial parts were extracted with methanol trough maceration, and resultant crude extracts were partitioned using solvents with increasing polarity. As previous studies mostly dealt with the phenolic content of these species, the phytochemical investigation mainly focused on nonpolar constituents, detected with GC-MS. The total phenolic and flavonoid content was also verified, and HPTLC analyses were performed. In order to explore the potential antiarthritic and anti-obesity properties, extracts and their fractions were evaluated for their anti-denaturation effects, with the use of the BSA assay, and for their ability to inhibit pancreatic lipase. The antioxidant properties and the inhibitory activity on the NO production were verified, as well. Almost all the extracts and fractions demonstrated good inhibitory effects on NO production. The n-hexane and dichloromethane fractions from T. majus, as well as the n-hexane fraction from C. ruber, were effective in protecting the protein from heat-induced denaturation (IC50 = 154.0 ± 1.9, 270.8 ± 2.3 and 450.1 ± 15.5 µg/mL, respectively). The dichloromethane fractions from both raw extracts were also effective in inhibiting pancreatic lipase, with IC50 values equal to 2.23 ± 0.02 mg/mL (for C. ruber sample), and 2.05 ± 0.02 mg/mL (T. majus). Obtained results support the traditional use of these species for their beneficial health properties and suggest that investigated plant species could be potential sources of novel antiarthritic and anti-obesity agents.

Seeds of Centranthus ruber and Valeriana officinalis Contain Conjugated Linolenic Acids with Reported Antitumor Effects.

Conjugated linolenic acids (CLNs) are naturally occurring fatty acids that are believed to have anticancer properties. In this study, we examined various plant seeds from herbs to discover seed oils containing CLNs. The ultraviolet spectra of total lipids from these seeds were measured. An absorption maximum around 270 nm was observed in seed oils belonging to the Valerianaceae family (Centranthus ruber and Valeriana officinalis). When the fatty acid compositions of these seed oils were measured, CLNs were detected. By silica column chromatography, neutral lipids (NLs), glycolipids, and phospholipids were eluted from seed oils of C. ruber and V. officinalis. Then, fatty acid compositions of these fractions were measured. This revealed that most of the CLNs in these seed oils existed in the NL fraction. When the NL fractions of these seed oils were reacted with lipase, CLNs showed good sensitivity to lipase hydrolysis. This suggested that the CLNs in the seed oils of C. ruber and V. officinalis existed predominantly at the sn-1,3 position of triacylglycerol and less at the sn-2 position. These results suggested that the CLNs from the seed oils of C. ruber and V. officinalis could easily be taken up by cancer cells as free fatty acids and had good potential as antitumor substances.

Purification of two valepotriates from Centranthus ruber by centrifugal partition chromatography: From analytical to preparative scale.

Considering chemical complexity of plant crude extracts, purification of natural products is a rate limiting process to identify new compounds as well as to obtain standard references for quantitative or qualitative purposes. In the present work, a centrifugal partition chromatography (CPC) method was developed to isolate and produce high quality reference standards of valtrate and 7-homovaltrate from Centranthus ruber L. roots. These two compounds are controversial aglycon iridioids regulated by the legislation on plant-based dietary supplements. A new biphasic solvent system suitable for CPC separation of valepotriates was developed. It was composed of methanol/hexane/water (5/5/0.8, v/v/v). It yielded a partition coefficient near 1 and a theoretical selectivity of 1.3 between both targeted compounds. Optimization of CPC experimental parameters at the analytical scale (50 mL- and 100 mL-column capacity) enabled compounds' separation with a flow rate of 8 mL/min at 2500 rpm. Then a scale up from a 100 mL-column capacity to a 1000 mL-column capacity has been studied using the "free-space between peaks" concept. It allowed an injected quantity 16 times higher in comparison to the maximal loading capacity of the 100 mL-column. Both valtrate and 7-homovaltrate were recovered in one single step with a purity over 97%. Further MS and NMR characterization allowed to confirm unambiguously the compounds' structures. The highly efficient CPC separation developed in this work provides valepotriates in amounts suitable for further study and strong bases for future industrial development.

[A novel screening system for Pseudomonas aeruginosa quorum sensing inhibitors].

Quorum sensing is an important gene regulatory mechanism in Pseudomonas aeruginosa and controls the expression of numerous virulence factors. We designed and constructed a screening system for quorum-sensing inhibitors. We developed the system by using the lasI and rhlA promoters fused with promoterless sacB as reporters. Using this system we screened a number of Chinese herb extracts, and identified three herb extracts containing inhibitors to the quorum-sensing system and to its regulated genes. The screening system developed was highly efficient and sensitive. It could serve as a useful tool to identify herb compounds that block infections but unlikely render antibiotic resistance in pathogens.

11-Methoxyviburtinal, a new iridoid from Valeriana jatamansi.

Five compounds of iridoids, lignan and phenylpropanoid glycosides were isolated from the roots of Valeriana jatamansi by column chromatography. Their structures were elucidated as 11-methoxyviburtinal (1), baldrinal (2), prinsepiol-4-omicron-beta-D-glucoside (3), coniferin (4), and hexacosanic acid (5) by spectroscopic analysis. 11-Methoxyviburtinal was a new compound, and others were isolated from the plant for the first time.

Sedative, anticonvulsant and behaviour modifying effects of Centranthus longiflorus ssp. longiflorus: a study of comparison to diazepam.

The aqueous extract of Centranthus longiflorus ssp. longiflorus (CLE) was investigated for sedative, anticonvulsant and behaviour modifying activity using thiopental sleeping, caffeine induced convulsion and forced swimming depression tests. When the effects of the aqueous extract of CLE (100 mg/kg) was compared to diazepam, it showed similar sedative and anticonvulsant effects to those produced by diazepam (5 mg/kg).

A new triterpene lactone from the roots of Patrinia scabiosaefolia.

A new triterpene lactone named patrinolide A (1) has been isolated from the roots of Patrinia scabiosaefolia (Valerianaceae). Its structure was determined to be 11beta,21beta-dihydroxy-3-oxooleanan-28,13beta-olide on the basis of spectral analysis, including 2D-NMR techniques. Key words: Patrinia scabiosaefolia, Valerianaceae, Lactone, Patrinolide, 11beta,21beta-dihydroxy-3-oxooleanan-28,13beta-olide.

Determination of iridoid glycosides by micellar electrokinetic capillary chromatography-mass spectrometry with use of the partial filling technique.

A fast and easy method was sought for determination of the iridoid glycosides catalpol, ketologanin, verbenalin, loganin, 8-epi-loganic acid, geniposidic acid and 10-cinnamoyl catalpol in plant samples. The method involved micellar electrokinetic capillary chromatography (MEKC) coupled on-line to mass spectrometry. The partial filling technique and electrospray ionization were used. Seven iridoid glycosides could be separated with use of MEKC under basic conditions. However, 8-epi-loganic acid and geniposidic acid could not be detected simultaneously with the five neutral iridoid glycosides by mass spectrometry. Therefore, only the neutral iridoid glycosides were screened from plant samples. Catalpol, verbenalin, loganin and possibly 10-cinnamoyl catalpol were found in an examination of seven plant species in the genera Plantago, Veronica, Melampyrum, Succisa, and Valeriana. Aucubin, which was not included in the sample mixture used in method development because of overlapping with catalpol in MEKC, was also detected. The limits of detection for the iridoid glycosides, both at the UV and at the mass spectrometer, are given.