Cyanogenesis in Aralia spinosa (Araliaceae).

A systematic survey of Aralia spinosa (Araliaceae), covering an entire growing season and including aboveground organs at various developmental stages, revealed that only about half of all samples collected showed cyanogenesis. Cyanogenesis was detected in inflorescences and leaves but is apparently restricted to certain harvest times or developmental stages. The structurally unusual triglochinin, characterized by a hex-2-enedioic acid partial structure, was the only cyanogenic glycoside detected. This is the first description of triglochinin in this species and in the family of Araliaceae. Triglochinin is biogenetically derived from tyrosine, which is in good agreement with the few cyanogenic glycosides previously detected in members of the Araliaceae family. Triglochinin was identified, characterized, and quantified by modern chromatographic methods, and the amount of enzymatically releasable hydrocyanic acid was determined qualitatively and quantitatively. Two isomers of triglochinin were detected chromatographically at minor levels. The isomeric pattern agreed well with literature data from other triglochinin-containing plants. This was confirmed in the two species, Triglochin maritima and Thalictrum aquilegiifolium, which were comparatively studied. In the case of A. spinosa, inflorescence buds harvested in July showed the highest content of triglochinin, just under 0.2% on a dry weight basis. The detection of triglochinin adds to the knowledge of toxicological properties and the dereplication of U(H)PLC/MS² data provides a comprehensive phytochemical profile of A. spinosa.

Novel Piperidine and 3,4-dihydro-2H-pyrrole Alkaloids from Tilia platyphyllos and Tilia cordata Flowers.

Lime flowers, traditionally used for medical purposes for the treatment of symptoms of the common cold and mental stress, consist of the dried inflorescences including the floral bracts of Tilia cordata, Tilia platyphyllos, Tilia × vulgaris, or mixtures thereof. During phytochemical investigations, 6 different alkaloids - not described until now - were detected in T. cordata and T. platyphyllos flowers. They have been isolated and characterized as alkaloids with a dihydro-pyrrole and a piperidine substructure, respectively. Compounds 1A: and 1B: (tiliines A and B) are characterized as 2 diastereomers containing a 2-methyl-3,4-dihydro-2H-pyrrol-3-ol, connected via a C-10 alkyl chain to a O-glucosylated hydroquinone moiety. Compounds 2A: and 2B: (tiliamines A and B) are diastereomers of a 2-methyl-substituted piperidin-3-ol, coupled via a C-9 alkyl chain again to an O-glucosylated hydroquinone moiety. Compounds 3A: and 3B: (tilacetines A and B) are 3-O-acetylated derivatives of tiliamines. Quantification of the 6 alkaloids by HPLC-ESI-qTOF analysis indicated the presence of all alkaloids in T. cordata flowers and T. platyphyllos flowers, bracts, and leaves, with tiliines A and B and tilacetines A and B being the major compounds. Acetone/water turned out be the best extraction solvent for the alkaloids, but ethanol and ethanol/water mixtures also can be used for effective extraction. Furthermore, the alkaloids are found in hot water extracts, which are typically used in the traditional medicine.

Aqueous Root Extract from Ononis spinosa Exerts Anti-adhesive Activity against Uropathogenic Escherichia coli.

Extracts from Ononis spinosa are traditionally used for urinary tract infections due to diuretic and anti-inflammatory activity. A potential influence on the virulence of uropathogenic Escherichia coli has not been investigated until now. The following study aimed to investigate the influence of an aqueous O. spinosa extract on uropathogenic E. coli and uropathogenic E. coli host cell interaction. A hot water extract from the roots of O. spinosa (O. spinosa extract) was characterized by LC-qTOF-MS. The influence of O. spinosa extract on the proliferation of uropathogenic E. coli UTI89 and on cell viability against human T24 bladder cells was investigated. Anti-adhesive activity of O. spinosa extract was assessed by flow cytometry, evaluating the adhesion of fluorescent-labelled UTI89 to T24 bladder cells. Internalization of uropathogenic E. coli into T24 cells was monitored by an invasion assay. O. spinosa extract was characterized by the presence of isoflavones, isoflavanones, licoagrosides, pterocarpans, tartaric acid derivatives, and saponines. O. spinosa extract had no influence on the proliferation of uropathogenic E. coli (125 - 1000 µg/mL) and did not influence the cell viability of T24 cells. Bacterial adhesion to T24 cells was significantly (p > 0.001) inhibited by O. spinosa extract in a concentration-dependent manner (125 - 1000 µg/mL) during coincubation. Preincubation of uropathogenic E. coli or T24 cells with O. spinosa extract reduced bacterial adhesion, but to a lower extent than during coincubation. Consequently, the reduced bacterial adhesion also leads to a reduced internalization of uropathogenic E. coli uropathogenic E. coli into the host cell. O. spinosa extract does not interact with FimH-mediated uropathogenic E. coli adhesion to host cells. From these data, the traditional use of O. spinosa extracts for urinary tract infections seems to be rationalized.

An Unsuccessful Attempt to Confirm the Occurrence of 4'-O-ß- d-Glucosyl-9-O-(6″-deoxysaccharosyl)olivil in Valerian Root.

The lignan 4'-O-ß- d-glucosyl-9-O-(6″-deoxysaccharosyl)olivil had previously been discovered in a methanolic extract of valerian root (Valeriana officinalis agg.) and characterized as a potent partial agonist at the A1 adenosine receptors. Today, countless scientific sources, webpages, and press articles mention this compound and discuss it as an active constituent for the sedative effect of this herbal drug. As no second report confirmed the occurrence of this lignan in valerian root during the 20 years since its first description in 1998, we intended to re-prove its presence by means of LCMS using other genuine or added lignans as a quantitative benchmark. Whilst those lignans were clearly detectable in methanolic valerian extracts of all six investigated batches of valerian root, no positive proof of 4'-O-ß- d-glucosyl-9-O-(6″-deoxysaccharosyl)olivil was achieved. Our result suggests that this compound does not occur regularly in valerian root in the amounts expected from the single report on the occurrence of this compound.

Influence of Cranberry Extract on Tamm-Horsfall Protein in Human Urine and its Antiadhesive Activity Against Uropathogenic Escherichia coli.

LC-MS characterized cranberry extract from the fruits of Vaccinium macrocarpon inhibited under in vitro conditions the bacterial adhesion of Escherichia coli strain 2980 uropathogenic E. coli (UPEC strains UTI89, NU14) to T24 bladder cells and adhesion of UPEC strain CFT073 to A498 kidney cells in a concentration-dependent manner. Within a biomedical study, urine samples from 16 volunteers (8 male, 8 female) consuming cranberry extract for 7 d (900 mg/d) were analyzed for potential antiadhesive activity against UPEC by ex vivo experiments. Results indicated inhibition of adhesion of UPEC strain UTI89 to human T24 bladder cells. Subgroup analysis proved significant inhibition of bacterial adhesion in case of urine samples obtained from male volunteers while female urine did not influence the bacterial attachment. Differences between antiadhesive capacity of urine samples from male/female volunteers were significant. Protein analysis of the urine samples indicated increased amounts of Tamm-Horsfall protein (THP, syn. uromodulin) in the active samples. Inhibition of bacterial adhesion by the urine samples was correlated to the respective amount of THP. As it is known that THP, a highly mannosylated glycoprotein, strongly interacts with FimH of UPEC, this will lead to a decreased interaction with uroplakin, a FimH-binding transmembrane protein of urothelial lining cells. From these data it can be concluded that the antiadhesive effect of cranberry after oral intake is not only related to the direct inhibition of bacterial adhesins by extract compounds but is additionally due to an induction of antiadhesive THP in the kidney.

Phytochemical Characterization of Low Molecular Weight Constituents from Marshmallow Roots (Althaea officinalis) and Inhibiting Effects of the Aqueous Extract on Human Hyaluronidase-1.

Extract RE was obtained from the roots of Althaea officinalis in a yield of 8.1%, related to the dried plant material, by extraction with MeOH-H2O (1:1), followed by precipitation with EtOH to remove high molecular weight constituents. Phytochemical investigation of RE revealed the presence of N-phenylpropenoyl-l-amino acid amides 1-5, 8% glycine betaine 6, about 9% total amino acids with proline as the main compound, and about 61% mono- and oligomeric carbohydrates with sucrose as the main compound. Further fractionation revealed the presence of a hypolaetin diglycoside (12) and four hypolaetin glycosides (7-9 and 11) with O-sulfocarbohydrate moieties; additionally, 4'-O-methylisoscutellarein-8-O-ß-d-(3″-O-sulfo)glucuronopyranoside (10) and the diglycosylated coumarin haploperoside D (13) were identified. The hypolaetin-O-sulfoglycosides 7-10 are new natural products. RE inhibited the enzymatic activity of surface-displayed human hyaluronidase-1 on Escherichia coli F470 cells with an IC50 of 7.7 mg/mL. RE downregulated mRNA expression of hyal-1 in HaCaT keratinocytes at 125 and 250 µg/mL, respectively. These data contribute to a deeper phytochemical understanding of marshmallow root extracts and to the positive influence of extracts used for therapy of irritated and inflamed buccal tissue and cough.

Antidiabetic Activities of an LC/MS Fingerprinted Aqueous Extract of Fagonia cretica L. in Preclinical Models.

Diabetes mellitus is a chronic disease and one of the most important public health challenges facing mankind. Fagonia cretica is a medicinal plant used widely in the Punjab in Pakistan. A recent survey has demonstrated that traditional healers and herbalists frequently use this plant to treat diabetes. In the current study, the traditional medicine was prepared as a tea, and the profile of the main metabolites present in the traditional medicine was analysed via LC/MS/MS. The extract was shown to contain a number of phenolic glycosides including quercetin-3-O-rutinoside, kaempferol-3-O-rutinoside, kaempferol-3-O-glycoside, kaempferol-3(6'-malonylglucoside), isorhamnetin-3-O-rutinoside, and isorhamnetin 3-(6″-malonylglucoside) in addition to two unidentified sulphonated saponins. The traditional medicine inhibits α-glucosidase in vitro with an IC50 of 4.62 µg/mL. The hypoglycaemic effect of the traditional medicine was evaluated in normoglycaemic and streptozotocin-treated diabetic rats, using glibenclamide as an internal control. The preparation (250 or 500 mg/kg body weight) was administered once a day for 21 consecutive days. The dose of 500 mg/kg was effective in the management of the disease, causing a 45 % decrease in the plasma glucose level at the end of the experimental period. Histological analysis of pancreatic sections confirmed that streptozotocin/nictotinamide treatment caused destruction of pancreatic islet cells, while pancreatic sections from the treatment groups showed that both the extract and glibenclamide partially prevented this deterioration. The mechanism of this protective effect is unclear. However, such a finding suggests that ingestion of the tea could confer additional benefits and should be investigated further.

Occurrence of Benzoic Acid Esters as Putative Catabolites of Prunasin in Senescent Leaves of Prunus laurocerasus.

Prunus laurocerasus is an evergreen shrub containing large quantities of the cyanogenic glycoside prunasin (1) in its leaves, which decomposes to prunasin amide (2) or glucose-1-benzoate (4) when the leaves become chlorotic as a result of senescence or pseudosenescence. This study was aimed at the systematic identification of senescence-associated metabolites to contribute further insight into the catabolism of 1. LC-ESIMS profiles of senescent and green leaves were analyzed by principal component analysis. In senescent leaves, the concentrations of 36 compounds were increased significantly including several benzoic acid derivatives, of which prunasin amide-6'-benzoate (5) and prunasin acid-6'-benzoate (6) were isolated and identified. The observed metabolic changes were also induced by treatment of P. laurocerasus shrubs with exogenous ethylene. The data presented support an oxidative catabolism of 1 without release of hydrogen cyanide and the remobilization of its nitrogen in the course of senescence. The results are discussed in the context of functional diversification and drug discovery, where senescent plant material represents a widely unexplored source for the discovery of natural products.

Isolation and Quantification of Oligomeric and Polymeric Procyanidins in the Aerial Parts of St. John's Wort (Hypericum perforatum).

Proanthocyanidins (condensed tannins) constitute a class of oligomeric and polymeric polyphenols with flavan-3-ols as monomeric building blocks. Despite the high impact of proanthocyanidins, these polyphenols are mostly quantified by colorimetric methods or by chromatographic determination of the flavan-3-ols as cleavage products or low molecular oligomers as lead compounds. For St. John's wort (Hyperici herba) from Hypericum perforatum, a protocol for preparative isolation of oligomeric and polymeric proanthocyanidins from an acetone-water extract by chromatography on Sephadex®LH20 in combination with preparative high-performance liquid chromatography on the diol stationary phase was developed, yielding procyanidin reference clusters with a defined degree of polymerization from 3 to 10. Identity and purity of these clusters was proven by high-performance liquid chromatography (RP18 and diol phase) and mass spectrometry. For identification and quantification of proanthocyanidin clusters from St. John's wort, an ICH-Q2 (International harmonized guideline for analytical validation) validated high-performance liquid chromatography method with fluorimetric detection was developed using an acetone-water extract of the herbal material, purified by solid-phase extraction for the removal of naphthodianthrones. The method enabled the quantification of procyanidin clusters with a degree of polymerization from 2 to 10. Analysis of nine batches of Hyperici herba from different sources indicated a high variability of proanthocyanidin content in the range from 8 to 37 mg/g. In all of the batches investigated, the trimer cluster DP3 was the dominant proanthocyanidin (about 40 %), followed by DP 4 (about 15 %) and DP5 (about 12 %). Monitoring of procyanidin distribution during seasonal growth of fresh plants of H. perforatum indicated the highest proanthocyanidin content in young plants (about 50 mg/g) and a time-dependent decrease during the growing season to about 16 mg/g. The highest proanthocyanidin content was found in young leaves and flowers, while the fruits were proanthocyanidin-free; older parts of the stem and the herb had a lower proanthocyanidin content. From these data, it can be concluded that proanthocyanidins serve as part of the plant defense system in the reproductive organs.

Bioassay-Guided Fractionation of a Leaf Extract from Combretum mucronatum with Anthelmintic Activity: Oligomeric Procyanidins as the Active Principle.

Combretum mucronatum Schumach. & Thonn. is a medicinal plant widely used in West African traditional medicine for wound healing and the treatment of helminth infections. The present study aimed at a phytochemical characterization of a hydroalcoholic leaf extract of this plant and the identification of the anthelmintic compounds by bioassay-guided fractionation. An EtOH-H2O (1:1) extract from defatted leaves was partitioned between EtOAc and H2O. Further fractionation was performed by fast centrifugal partition chromatography, RP18-MPLC and HPLC. Epicatechin (1), oligomeric proanthocyanidins (OPC) 2 to 10 (mainly procyanidins) and flavonoids 11 to 13 were identified as main components of the extract. The hydroalcoholic extract, fractions and purified compounds were tested in vitro for their anthelmintic activity using the model nematode Caenorhabditis elegans. The bioassay-guided fractionation led to the identification of OPCs as the active compounds with a dose-dependent anthelmintic activity ranging from 1 to 1000 µM. Using OPC-clusters with a defined degree of polymerization (DP) revealed that a DP ≥ 3 is necessary for an anthelmintic activity, whereas a DP > 4 does not lead to a further increased inhibitory effect against the helminths. In summary, the findings rationalize the traditional use of C. mucronatum and provide further insight into the anthelmintic activity of condensed tannins.

Covalent modification of human serum albumin by the natural sesquiterpene lactone parthenolide.

The reactivity of parthenolide (PRT), a natural sesquiterpene lactone from Tanacetum parthenium (Asteraceae), with human serum albumin (HSA) was studied by UHPLC/+ESI-QqTOF MS analysis after tryptic digestion of albumin samples after incubation with this compound. It was found that the single free cysteine residue, C34, of HSA (0.6 mM) reacted readily with PRT when incubated at approximately 13-fold excess of PRT (8 mM). Time-course studies with PRT and its 11ß,13-dihydro derivative at equimolar ratios of the reactants revealed that PRT under the chosen conditions reacts preferably with C34 and does so exclusively via its α-methylene-γ-lactone moiety, while the epoxide structure is not involved in the reaction.

PLS-Prediction and Confirmation of Hydrojuglone Glucoside as the Antitrypanosomal Constituent of Juglans Spp.

Naphthoquinones (NQs) occur naturally in a large variety of plants. Several NQs are highly active against protozoans, amongst them the causative pathogens of neglected tropical diseases such as human African trypanosomiasis (sleeping sickness), Chagas disease and leishmaniasis. Prominent NQ-producing plants can be found among Juglans spp. (Juglandaceae) with juglone derivatives as known constituents. In this study, 36 highly variable extracts were prepared from different plant parts of J. regia, J. cinerea and J. nigra. For all extracts, antiprotozoal activity was determined against the protozoans Trypanosoma cruzi, T. brucei rhodesiense and Leishmania donovani. In addition, an LC-MS fingerprint was recorded for each extract. With each extract's fingerprint and the data on in vitro growth inhibitory activity against T. brucei rhodesiense a Partial Least Squares (PLS) regression model was calculated in order to obtain an indication of compounds responsible for the differences in bioactivity between the 36 extracts. By means of PLS, hydrojuglone glucoside was predicted as an active compound against T. brucei and consequently isolated and tested in vitro. In fact, the pure compound showed activity against T. brucei at a significantly lower cytotoxicity towards mammalian cells than established antiprotozoal NQs such as lapachol.

Extracts from Rhododendron ferrugineum do not exhibit grayanotoxin I: an analytical survey on grayanotoxin I within the genus Rhododendron.

For quantitative determination of grayanotoxin I (1) in plant material, a GC/MS method was developed after trimethylsilyl derivatisation of the analytes. Forskolin (5) was used as an internal standard for quantification. ICH-compliant method validation indicated sufficient specificity, precision, quantitation (15 µg/mL) and detection (5 µg/mL) limits. Regression analysis showed that a non-linear (polynomial) model was preferable to a linear one. For isolation of grayanotoxin I reference material from Rhododendron ponticum leaves, an efficient two-step fast centrifugal partition chromatography isolation protocol is described. A survey of 17 different plant species from the genus Rhododendron revealed high grayanotoxin I content for R. catawbiense, R. ponticum, R. degronianum subsp. yakushimanum, R. × sochadzeae, R. moupinense, R. galactinum, and R. mucronatum var. ripense. The content of this compound in leaf material from R. ponticum decreased rapidly during drying process. Grayanotoxin I was not detected in different batches of fresh leaves and fruits from R. ferrugineum. In contrast to the claims of German health authorities, this traditionally used herb therefore cannot be evaluated as toxic due to the presence of grayanotoxin I.

Phenylpropanoid-substituted procyanidins and tentatively identified procyanidin glycosides from hawthorn (Crataegus spp.).

The rational use of hawthorn leafs and flowers from Crataegus spp. for declining cardiac performance is mainly due to flavon-C-glycosides and oligomeric procyanidins (OPC). From OPC-enriched extracts from different batches, a dimeric phenylpropanoid-substituted procyanidin (cinchonain II b, 1) was isolated and characterized by MS, CD, and NMR. Also the presence of higher oligomeric cinchonains (degree of polymerization 3 to 8) in hawthorn extracts was shown by a specific ultrahigh-pressure liquid chromatography-ESI-qTOF-MS method. Interestingly, strong evidence for the occurrence of oligomeric procyanidin hexosides was found by ultrahigh-pressure liquid chromatography-ESI-qTOF-MS analysis which additionally revealed the presence of peaks indicative of dimeric procyanidin hexosides by their exact mass, which were clearly distinguishable from the cinchonain II type peaks.

Aqueous extract from Equisetum arvense stimulates the secretion of Tamm-Horsfall protein in human urine after oral intake.

BACKGROUND: Within European traditional phytotherapy, extracts from different herbal plants are used for prevention and therapy of uncomplicated urinary tract infections and for flushing out of kidney grits. Besides increased urine flow by slight diuretic effects, also stimulation of Tamm-Horsfall protein (syn. THP, uromodulin) in the distal part of the kidney could explain reduced kidney gravel and anti-virulent activity against uropathogenic E. coli. PURPOSES: Evaluation of THP-inducing activity of extracts from Equisetum arvense, Levisticum officinalis, Ilex paraguariensis, Juniperus communis, Urtica dioica, and Taraxacum officinale by quantification of THP in urine samples after oral application to humans. STUDY DESIGN: 7 days p.o. application of the test intervention to healthy volunteers (n = 10 per intervention group) and analysis of urine samples at day 1 (untreated control values), and days 3, 6 and 8 on THP content by validated ELISA. Antiadhesive activity of urine samples was monitored by flow cytometry using UPEC strain NU14 against human T24 bladder cells. RESULTS: An aqueous extract from E. arvense, fully characterized by a specific LC-MS method, induced THP concentration in urine samples significantly during a 7-day p.o. application up to 300%, related to the untreated controls. Ex vivo investigation of the individual and pooled urine samples with elevated THP concentrations showed good correlation to antiadhesive effects against UPEC NU14 to T24 cells. Urine samples of the Equisetum treated volunteers had no effect on the proliferation and on biofilm formation of UPEC NU14. Silica excretion in the urine samples had no correlation to the respective THP levels. Monitoring of electrolyte content in the urine samples indicat ed diuretic effects of the intervention with Equisetum extract. Detailed phytochemical analysis of the Equisetum extract by LC-MS and LC-UV revealed an analytical protocol, which identified > 80 compounds from the extract by MS evaluations and 18 compounds by UV detection. This protocol will provide a valuable tool for future quality control of Equisetum extract. CONCLUSION: Aqueous extract from E. arvense significantly stimulates THP secretion in urine samples after 7 days of oral intake and inhibits the interplay between UPEC and bladder host cells. This could explain the therapeutic use of this herbal material for urinary tract infections and kidney gravel. Detailed phytochemical analysis of the Equisetum extract by LC-MS and LC-UV revealed an analytical protocol, which identified > 82% of all eluted compounds. This protocol will provide a valuable tool for future quality control of Equisetum extract.

Phytochemical and functional analysis of horseradish (Armoracia rusticana) fermented and non-fermented root extracts.

BACKGROUND: The roots of horseradish (Armoracia rusticana) are used for infections of respiratory airway and for urinary tract infections due to isothiocyanates (ITC), enzymatically formed during fermentation of glucosinolates by myrosinase. HYPOTHESIS/PURPOSE: The present study aims to present a comprehensive overview on the phytochemical composition of A. rusticana roots, especially concerning isothiocyanates and respective glucosinolates. The complex flavonoid spectrum of the herbal material is reviewed. Published data on in vitro activity of horseradish extracts and isolated compounds are summarized. These data indicate well-established use of horseradish as an antibacterial remedy against bacterial infections of the airway and urinary tract. STUDY DESIGN: To answer the question if other compounds from A. rusticana beside ITC contribute to the antibacterial activity, non-targeted LC-MS studies were performed with fermented and non-fermented horseradish extracts, and detailed phytochemical profiles were established. RESULTS: Comparative investigations on the antibacterial activity indicated that only ITC-containing extracts and fractions exert antibacterial activity. The huge variety of non-ITC compounds do not significantly contribute to the antibacterial activity, but can be used for analytical characterisation and quality control of the herbal material. Detailed phytochemical analysis additionally revealed a variety of compounds, not described until now for horseradish roots: the flavonol glycosides kaempferol-3-O-ß-d-xylopyranosyl-(1''' â†’ 2'')-ß-d-galactopyranoside, kaempferol-3-O-α-l-rhamnopyranosyl-(1''' â†’ 6'')-ß-d-glucopyranoside, kaempferol-3-O-ß-d-glucopyranoside, Kaempferol-3-O-ß-d-xylopyranosyl-7-O-ß-d-glucopyranoside, Kaempferol-3-O-ß-d-xylopyranosyl-(1'''' â†’ 2''')-ß-d-galactopyranoside-7-O-ß-d-glucopyranoside, the oxo-indole derivative spirobrassinin, the phenylthiazole 2-methylsulfanyl-4-phenyl-4,5-dihydro-1,3-thiazole, a series of lysophophatidylethanolamine and 13 different N-phenylpropenoyl-L-amino acids. CONCLUSION: The antibacterial effects of horseradish are only due to the presence of glucosinolates resp. the corresponding ITC, and the detailed overall composition of horseradish extracts has been reported.

Cytotoxicity, genotoxicity, and gene expression changes induced by methanolic extract of Moringa stenopetala leaf with LC-qTOF-MS metabolic profile.

Moringa stenopetala (Baker f.) Cuf.and other Moringa species have traditionally been used to treat various diseases. The purpose of this study was to determine the cytotoxic and genotoxic effects of the methanolic extract of M. stenopetala leaf and its fractions on selected tumor cells. Cytotoxicity was determined by MTT assay. The comet assay was used toassess DNA damage, and gel electrophoresis was used to determine DNA fragmentation. Gene expression was analyzed by qPCR using two specific genes for each cancer cell line. Fractionation of the methanolic extract (E-1) on Diaion HP-20 yielded five fractions (Fr-2 to Fr-6); only Fr-4 and Fr-6 were cytotoxic to breast cancer cells (MCF-7; IC50 = 58.3 ± 0.93 and 35.8 ± 2.44 µg/mL, respectively), human hepatocellular carcinoma cells (HepG2; IC50 = 57.8 ± 1.57 and 39.3 ± 1.90 µg/mL, respectively), and Fr-4 was cytotoxic to human colon cancer cells (HCT-116; IC50 = 94.2 ± 4.9 µg/mL). In addition, exposure of the cancer cells to Fr-4 and Fr-6 resulted in a high level of DNA damage. Moreover, relative expression of MTAP and CDKN2A in MCF-7 were increased, whereas expression of p21 and p53 in HCT-116, and APC and TERT in HepG2 were decreased, similar to that of doxorubicin. LC-qTOF-MS was used to identify metabolites in E-1, the majority of which were enriched in Fr-4. Two terpenes (loliolide and dihydroactinidiolide), the majority of the flavonoids, and niazirin were about two fold enriched in Fr-4, whereas the majority of the lipids were 4-10 fold enriched. However, Fr-6 hardly showed compounds other than the two terpenes that were enriched 1.5 and 7 fold. The findings suggest that Fr-4 and Fr-6 are promising sources of compounds possessing cytotoxic and genotoxic properties.

Sesterterpenoids and other constituents of Salvia sahendica.

A new sesterterpene (1), a new norsesterterpene (3), and two new norditerpenes (4, 5) were isolated from the aerial parts of Salvia sahendica, together with 12 known compounds, comprising a sesterterpene, a sesquiterpene, a diterpene, two triterpenes, two steroidal compounds, and five flavonoids. The structures of the new compounds were established by spectroscopic data interpretation, and in the case of 4, its structure was confirmed by single-crystal X-ray analysis.

Regulation of dioxin receptor function by different beta-carboline alkaloids.

The dioxin receptor, also known as arylhydrocarbon receptor (AhR), is a ligand-activated transcription factor that mediates the toxicity of dioxins and related environmental contaminants. In addition, there is a growing list of natural compounds, mainly plant polyphenols that can modulate AhR function and downstream signaling with quite unknown consequences for cellular function. We investigate the potential of four different beta-carboline alkaloids to stimulate AhR signaling in human hepatoma cells and keratinocytes. Three test substances, namely rutaecarpine, annomontine and xestomanzamine A, increase AhR-driven reporter gene activity as well as expression of two AhR target genes in a dose-dependent and time-dependent manner. Additionally, the three test alkaloids stimulate cytochrome P450 (CYP) 1 enzyme activity without showing any antagonistic effects regarding benzo(a)pyrene-stimulated CYP1 activation. The AhR-activating property of the beta-carbolines is completely abrogated in AhR-deficient cells providing evidence that rutaecarpine, annomontine and xestomanzamine A are natural stimulators of the human AhR. The toxicological relevance of beta-carboline-mediated AhR activation is discussed.