Identification and quantification of cannabinol as a biomarker for local hemp retting in an ancient sedimentary record by HPTLC-ESI-MS.

Cannabis products have been used in various fields of everyday life for many centuries, and applications in folk medicine and textile production have been well-known for many centuries. For traditional textile production, hemp fibers were extracted from the stems by water retting in stagnant or slow-moving waters. During this procedure, parts of the plant material' among them phytocannabinoids' are released into the water. Cannabinol (CBN) is an important degradation product of the predominant phytocannabinoids found in Cannabis species. Thus, it is an excellent indicator for present as well as ancient hemp water retting. In this study, we developed and validated a simple and fast method for the determination of CBN in sediment samples using high-performance thin-layer chromatography (HPTLC) combined with electrospray ionization mass spectrometry (ESI-MS), thereby testing different extraction and cleanup procedures' as well as various sorbents and solvents for planar chromatography. This method shows a satisfactory overall analytical performance with an average recovery rate of 73%. Our protocol enabled qualitative and quantitative analyses of CBN in samples of a bottom sediment core' having been obtained from a small lake in Northern India, where intense local retting of hemp was suggested in the past. The analyses showed a maximum CBN content in pollen zone 4 covering a depth range of 262-209 cm, dating from approximately 480 BCE to 1050 CE. These findings correlate with existing records of Cannabis-type pollen. Thus, the method we propose is a helpful tool to track ancient hemp retting activities. Graphical Abstract.

Mapping Natural Dyes in Archeological Textiles by Imaging Mass Spectrometry.

Organic dyes of animal and plant origin have often been used by our ancestors to create textiles with polychromic ornamental patterns, and dyestuff analyses reveal how ancient cultures used these natural colorants. Mass spectrometry can characterize ancient colorants from these textiles, but its combination with separation techniques such as liquid chromatography requires the destruction of the pattern to extract organic dyes from the fabrics. In this study we applied mass spectrometry imaging (MS imaging) on colorful patterned textiles to show the spatial distribution of indigo-type and anthraquinone-type dyes. We evaluated different sample preparation techniques for matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-MS imaging, e.g. the production of imprints in TLC (thin layer chromatography) aluminum sheets and the embedding of the material in Technovit7100 to produce thin sections. Our protocol enabled the detection of indigo-type dyes directly on a historic textile of more than 2,000 years old embedded in Technovit7100. This is the first-time application of MALDI-TOF-MS imaging to map different organic dyestuffs on archeological remains.

Homopiperazine-rhodamine B adducts of triterpenoic acids are strong mitocans.

Parent pentacyclic triterpenoic acids such as ursolic-, oleanolic, glycyrrhetinic, betulinic and boswellic acid were converted into their acetylated piperazinyl amides that were coupled with rhodamine B. SRB assays to evaluate their cytotoxicity showed all of these triterpene-homopiperazinyl-rhodamine adducts 16-20 being highly cytotoxic for a panel of human tumor cell lines even in nanomolar concentrations while being significantly less cytotoxic for non-malignant cells. Interestingly enough, these compounds were even more cytotoxic than previously prepared piperazinyl analogs, thus making the homopiperazinyl spacer a very interesting scaffold for the development of biologically active compounds. Extra staining experiments showed that the cytostatic effect of compounds 18 and 20 onto A2780 cancer cells is due to their ability to act as a mitocan.

Betulinic acid derived hydroxamates and betulin derived carbamates are interesting scaffolds for the synthesis of novel cytotoxic compounds.

The betulinic acid-derived hydroxamates 5-18, the amides 19-24, and betulin-derived bis-carbamates 25-28 as well as the carbamates 31-40 and 44-48 were prepared and evaluated for their antiproliferative activity in a photometric sulforhodamine B (SRB) assay against several human cancer cell lines and nonmalignant mouse fibroblasts (NIH 3T3). While for 3-O-acetyl hydroxamic acid 5 EC50 values as low as EC50 = 1.3 µM were found, N,O-bis-alkyl substituted hydroxamates showed lowered cytotoxicity (EC50 = 16-20 µM). In general, hydroxamic acid derivatives showed only reduced selectivity for tumor cells, except for allyl substituted compound 13 (EC50 = 5.9 µM for A2780 human ovarian carcinoma cells and EC50 > 30 µM for nonmalignant mouse fibroblasts). The cytotoxicity of betulinic acid derived amides 19-24 and of betulin derived bis-carbamates 25-28 was low, except for N-ethyl substituted 25. Hexyl substituted 39 showed EC50 = 5.6 µM (518A2 cells) while for mouse fibroblasts EC50 > 30 was determined.

A fast and reliable detection of indigo in historic and prehistoric textile samples.

We present a method requiring no sample preparation for the direct identification of indigoid colorants in tiny amounts in ancient historic fabrics using ASAP®-MS. Exact determinations were completed in less than 1 min. Copyright © 2015 John Wiley & Sons, Ltd.

Resveratrol derived butyrylcholinesterase inhibitors.

Novel polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them are good inhibitors of butyrylcholinesterase; one of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.

Does one keto group matter? Structure-activity relationships of glycyrrhetinic acid derivatives modified at position C-11.

Several triterpenoic acids display a remarkable cytotoxicity on tumor cells. Glycyrrhetinic acid - the main content of the licorice root - possesses an apoptotic effect on tumor cells. Previous studies pointed out the presence of a keto group at position C-11 in glycyrrhetinic acid derivatives as the main reason for its apoptotic activity. Several pairs of derivatives were synthesized differing only at position C-11. These compounds were tested in a sulforhodamine B colorimetric assay for cytotoxicity screening on 12 tumor cell lines and mouse embryonic fibroblasts (NIH3T3). Our results show that there is no direct relation between the existence of the C-11 keto group and the apoptotic activity of the compounds.

Conversions at C-30 of glycyrrhetinic acid and their impact on antitumor activity.

The extracts of the roots of licorice have been used in traditional and folk medicine to treat a broad variety of maladies. The main ingredient of these extracts is glycyrrhicinic acid. Its aglycon, glycyrrhetinic acid, has many biological activities, among them a pronounced cytotoxicity against tumor cells. In this study we varied glycyrrhetinic acid at position C-30 to get "simple" derivatives, for example esters, amides and a nitrile. The influence of these changes on the cytotoxic activity is noteworthy and was determined by a colorimetric sulphorhodamine B test using 7 human tumor cell lines and mouse embryonic fibroblasts (NIH3T3) for comparison. A Trypan blue test as well as an acridine orange/ethidium bromide test was used to discover the ability of the compounds to induce apoptosis.

Synthesis and biological evaluation of antitumor-active arglabin derivatives.

Arglabin derivatives varied at the endo- or exo-cyclic double bond were synthesized and studied in a colorimetric sulforhodamine B assay for their cytotoxicity. Variations on the endocyclic double bond led to compounds of reduced cytotoxicity whereas derivatives from the reaction of the α-methylene-γ-butyrolactone moiety led to compounds of similar or only slightly reduced cytotoxicity but different, cell line-dependent selectivity. In addition, arglabin is an excellent starting material for the synthesis of the guaianolide arborescin.

Synthesis and antitumor activity of ring A modified glycyrrhetinic acid derivatives.

Triterpenoic acids show many pharmacological effects, among them an antiinflammatory or an antitumor activity. One of these, glycyrrhetinic acid (1) is of interest because of its antitumor profile. Glycyrrhetinic acid is not only cytotoxic but also triggers apoptosis in various human tumor cell lines. To improve the cytotoxicity of parent 1 we set out to synthesize new derivatives of it--differing in structure and lipophilicity. These compounds were tested in a sulforhodamine B assay for cytotoxicity, and screened for their ability to induce apoptosis using an acridine orange/ethidium bromide assay and trypan blue staining. The most active compound, 34, a benzyl glycyrrhetinate holding an extra 3-N-(3-aminopropyl)glycyl substituent showed IC(50) between 1.96 and 5.14 µm for five human cancer cell lines and triggers apoptosis in 80% of the cells.

Improvement of the cytotoxicity and tumor selectivity of glycyrrhetinic acid by derivatization with bifunctional amino acids.

Glycyrrhetinic acid (GA) is a major ingredient of the dried extract of licorice roots; its antitumor activity is low compared to other members of the triterpenoic family. For example, oleanolic acid, betulin or betulinic acid are more cytotoxic with a pronounced activity for tumor cells. GA, however, is easily to earn, cheap and shows apoptotic effects on tumor cells--like the other triterpenoic acids. These facts bring GA and derivatives in the focus of our scientific interest. Here we tried to improve the poor cytotoxicity of GA by simple derivatization. Thus, we selected various glutamyl and aspartyl substituents for the synthesis of C(3) esters of GA methyl ester. A short (3-5 steps) synthesis was elaborated that allowed to access more effective compounds. One compound, methyl 3ß 3-(O-benzyl-L-glutamyl)-11-oxo-olean-12-en-30-oate (5), having a glutamyl substituent with a benzyl protected side chain showed up to 67-fold higher cytotoxicity and an up to 140-fold better selectivity towards tumor cells than parent GA. All compounds were evaluated by a sulforhodamine B assay as well as by a trypan blue test and extra acridine orange/ethidium bromide tests for apoptosis.

Amplification of the inhibitory activity and reversal of the selectivity of miglitol by C(2')-monofluorination.

Selective monofluorination of the α-glycosidase inhibitor and antidiabetic agent miglitol at positions C(2') or C(6) creates competitive inhibitors of glycosidases. Introducing a fluorine substituent at position C(6) results in a reduced binding to the enzyme whereas fluorination at C(2') produces an inhibitor with an activity four times higher than the parent compound. This compound is selective for the α-galactosidase from green coffee beans. Its screening against a panel of human cell lines showed a low cytotoxicity, therefore, making this compound an interesting candidate for further clinical investigations.

Synthesis and biological activity of some antitumor active derivatives from glycyrrhetinic acid.

Aminoalkyl substituted derivatives were synthesized starting from glycyrrhetinic acid methyl ester and screened for antitumor activity in a panel of 15 human cancer cell lines by an SRB assay. The most compound 7 possesses an aminohexyl side chain, induces apoptosis and shows IC50 values of 0.6-3.0 µM.

Synthesis, cytotoxicity and liposome preparation of 28-acetylenic betulin derivatives.

Several novel betulin derivatives were prepared and evaluated for their antitumor activity. 3-O-acetylbetulinic aldehyde served as an ideal starting material for the synthesis of 28-acetylenic derivatives. These compounds were further transformed into pyrazoles and 1,2,3-triazoles. Also, the synthesis of 3-amino substituted butenolides was carried out. The compounds were screened for their antitumor activity in a panel of 15 human cancer cell lines in a sulforhodamine B (SRB) assay. Several compounds showed a noteworthy antitumor activity. In addition, the possibility of encapsulation into liposomes was examined, thereby resulting in an increased cytotoxicity. The results from a trypan-blue test and from DNA laddering provided evidence for an apoptotic cell death.

Synthesis of an antitumor active endoperoxide from 11-keto-beta-boswellic acid.

An endoperoxide was synthesized starting from 11-keto-beta-boswellic acid and screened for antitumor activity in a panel of 15 human cancer cell lines by an SRB assay. The compound induces apoptosis and shows an average IC(50) value of 0.4-4.5 microM.

Synthesis and biological evaluation of antitumour-active betulin derivatives.

The reaction of betulinic aldehydes with various carbon nucleophiles gave a series of new betulin derivatives, among them epoxides, glycidic derivatives and beta-hydroxy carbonyl compounds. Subsequent transformations of the beta-hydroxy carbonyls lead to 1,3-diketo- and alpha,beta-unsaturated betulin derivatives. These compounds were assayed for cytotoxicity using 15 human cancer cell lines and a colorimetric SRB-assay. Several compounds revealed significant antitumour activity.

Synthesis of monomeric and dimeric acridine compounds as potential therapeutics in Alzheimer and prion diseases.

Starting from substituted 9-chloroacridines, a series of quinacrine and spacered dimeric acridine compounds was prepared. Their ability to interrupt the protein association of prion- and Alzheimer-specific proteins and Ab peptides was explored using a fast screening system based on FACS analysis. The bis-acridines displayed a higher activity than the corresponding monomers. Among these derivatives, best results were obtained with the 2,4-dimethoxy-6-nitro compound 7h for Abeta-peptides and the 2-methoxy-6-nitro compound 7f for PrP.

Antitumoractive endoperoxides from triterpenes.

A series of triterpene endoperoxides was synthesized and screened for antitumor activity in a panel of 15 human cancer cell lines by a sulforhodamine-B (SRB) assay. The compounds induce apoptosis and show excellent antitumor activity.

Synthesis of dimeric quinazolin-2-one, 1,4-benzodiazepin-2-one, and isoalloxazine compounds as inhibitors of amyloid peptides association.

The synthesis of dimeric compounds derived from quinazolin-2-one and 1,4-benzodiazepin-2-one possessing a piperazine or homopiperazine spacer was investigated. In addition, a piperazine spacered bis-isoalloxazine and a bis-riboflavin compound were prepared and their ability to interrupt the association of prion proteins and Alzheimer-specific Abeta peptides was investigated using a fast screening system based on flow cytometry. The bis-isoalloxazine 14 was identified as a new lead structure.

Alkylthio bridged 44 cve triangular platinum clusters: synthesis, oxidation, degradation, ligand substitution, and quantum chemical calculations.

Acetylplatinum(II) complexes trans-[Pt(COMe)Cl(L)2] (L = PPh3, 2a; P(4-FC6H4)3, 2b) were found to react with dialkyldisulfides R2S2 (R = Me, Et, Pr, Bu; Pr = n-propyl, Bu = n-butyl), yielding trinuclear 44 cve (cluster valence electrons) platinum clusters [(PtL)3(mu-SR)3]Cl (4). The analogous reaction of 2a-b with Ph2S2 gave SPh bridged dinuclear complexes trans-[{PtCl(L)}2(mu-SPh)2] (5), whereas the addition of Bn2S2 (Bn = benzyl) to 2a ended up in the formation of [{Pt(PPh3)}3(mu3-S)(mu-SBn)3]Cl (6). Theoretical studies based on the AIM theory revealed that type 4 complexes must be regarded as triangular platinum clusters with Pt-Pt bonds whereas complex 6 must be treated as a sulfur capped 48 ve (valence electrons) trinuclear platinum(II) complex without Pt-Pt bonding interactions. Phosphine ligands with a lower donor capability in clusters 4 proved to be subject to substitution by stronger donating monodentate phosphine ligands (L' = PMePh2, PMe2Ph, PBu3) yielding clusters [(PtL')3(mu-SR)3]Cl (9). In case of the reaction of clusters 4 and 9 with PPh2CH2PPh2 (dppm), a fragmentation reaction occurred, and the complexes [(PtL)2(mu-SMe)(mu-dppm)]Cl (12) and [Pt(mu-SMe)2(dppm)] (13) were isolated. Furthermore, oxidation reactions of cluster [{Pt(PPh3)}3(mu-SMe)3]Cl (4a) using halogens (Br2, I2) gave dimeric platinum(II) complexes cis-[{PtX(PPh3)}2(mu-SMe)2] (14, X = Br, I) whereas oxidation reactions using sulfur and selenium afforded chalcogen capped trinuclear 48 ve complexes [{Pt(PPh3)}3(mu3-E)(mu-SMe)3] (15, E = S, Se). All compounds were fully characterized by means of NMR and IR spectroscopy, microanalyses, and ESI mass spectrometry. Furthermore, X-ray diffraction analyses were performed for the triangular cluster 4a, the trinuclear complex 6, as well as for the dinuclear complexes trans-[{Pt(AsPh3)}2(mu-SPh)2] (5c), [{Pt(PPh3)}2(mu-SMe)(mu-dppm)]Cl (12a), and [{{PtBr(PPh3)}2(mu-SMe)2] (14a).