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

Synthesis of cyclopropyl-substituted furans by Brønsted acid promoted cascade reactions

Chloroacetic acid promotes an efficient and diastereoselective intramolecular cascade reaction of electron-deficient ynenones to deliver products featuring a 2,3,5-trisubstituted furan bearing a fused cyclopropyl substituent at the 5-position. Synthetically relevant polycyclic building blocks featuring rings of various sizes and heteroatoms have been synthesized in high yield using this mild acid-catalyzed reaction

Revisiting capsaicin and nonivamide : their analogs exert strong inhibitory activity against cholinesterases

The scientific community has long been interested in capsaicin, and the extensive hunt for AChE and BChE enzyme inhibitors is still ongoing. In this investigation analogs of capsaicin, such as the pharmaceutical nonivamide, which is preferred in clinical settings for the topical treatment of pain, were explored in the search for appropriate inhibitors. Thus, to test their inhibitory effect on AChE and BChE, we synthesized a short series of derivatives derived from vanillylamide. Consequently, it was discovered that compounds 12, 34, and 35, which have Ki values in the sub-micromolar concentration range, are especially effective inhibitors. Compound 12 demonstrated dual mixed-type (competitive/uncompetitive) inhibitory activity for both enzymes; compound 34 showed selective mixed-type inhibitory activity for AChE, and compound 35 was found to have selective uncompetitive activity for AChE

Arylsulfonamido-alkyl-sulfamates act as inhibitors of bovine carbonic anhydrase II

A small library of arylsulfonamido-alkyl sulfamates was prepared by a two-step synthesis from readily available starting materials. The compounds were tested for their ability to inhibit bovine carbonic anhydrase II. Several of them were found as good competitive inhibitors holding Ki values as low as Ki = 0.9 μM (compound 47b). The activity was influenced by the substitution pattern of the arylsulfonamide moiety as well as the length of the spacer to the distal sulfamate group. Molecular docking studies were used to substantiate these findings. For the aryl-substituted analogues, the increase in inhibitory activity for compounds with a shorter spacer can be explained by stabilization via aromatic π-interactions. For the cyclopropyl or methylsulfonyl substituted analogues, their inhibitory activity can be attributed to their reduced steric hindrance. These results provide a basis for designing effective CA II inhibitors

Ethylenediamine derived carboxamides of betulinic and ursolic acid as potential cytotoxic agents

Two easily accessible, natural occurring triterpenoids, betulinic and ursolic acid, were used as starting materials for the synthesis of novel cytotoxic agents. A set of 28 ethylenediamine-spacered carboxamides was prepared holding an additional substituent connected to the ethylenediamine group. The compounds were screened in SRB assays to evaluate their cytotoxic activity employing several human tumor cell lines. Betulinic acid-derived carboxamides 17–30 showed significantly higher cytotoxicity than their ursolic acid analogs 3–16. In particular, compounds 25 and 26 were highly cytotoxic, as indicated by EC50 values lower than 1 μM.Publikationsfond ML

Stable triterpenoid iminium salts and their activity as inhibitors of butyrylcholinesterase

Amides derived from platanic acid (30-nor-lupane skeleton) were converted in two steps into 21-aza-17,19-ethano-19-nor-urs-20-en-21-ium chlorides. These ursane-skeleton iminium salts are first in their class, and some of them proved as selective inhibitors of the enzyme butyrylcholinesterase while holding no inhibitory activity for acetylcholinesterase.Publikationsfonds ML

Platanic acid derived amides are more cytotoxic than their corresponding oximes

Albeit platanic acid has been known since 1956, its potential to act as a valuable starting material for the synthesis of cytotoxic agents has been neglected for many years. Hereby we describe the synthesis of a small library of amides and oximes derived from 3-O-acetyl-platanic acid, and the results of their screening as cytotoxic agents for several human tumor cell lines. As a result, while the cytotoxicity of the oximes was diminished as compared to the parent amides, the homopiperazinyl amide 5 held the highest cytoxicity (EC50 = 0.9 μM for A375 human melanoma cells). Extra FACS and cell cycle measurements showed compound 5 to act onto A375 cells rather by apoptosis than by necrosis.Publikationsfonds ML

Synthesis of rhodamine-conjugated lupane type triterpenes of enhanced cytotoxicity

Various conjugates with rhodamines were prepared by starting with betulinic acid (BA) and platanic acid (PA). The molecules homopiperazine and piperazine, which were identified in earlier research, served as linkers between the rhodamine and the triterpene. The pentacyclic triterpene’s ring A was modified with two acetyloxy groups in order to possibly boost its cytotoxic activity. The SRB assays’ cytotoxicity data showed that conjugates 13–22, derived from betulinic acid, had a significantly higher cytotoxicity. Of these hybrids, derivatives 19 (containing rhodamine B) and 22 (containing rhodamine 101) showed the best values with EC50 = 0.016 and 0.019 μM for A2780 ovarian carcinoma cells. Additionally, based on the ratio of EC50 values, these two compounds demonstrated the strongest selectivity between malignant A2780 cells and non-malignant NIH 3T3 fibroblasts. A375 melanoma cells were used in cell cycle investigations, which showed that the cells were halted in the G1/G0 phase. Annexin V/FITC/PI staining demonstrated that the tumor cells were affected by both necrosis and apoptosis

On the influence of the rhodamine substituents onto the cytotoxicity of mitocanic maslinic acid rhodamine conjugates

Maslinic acid was converted via a di-acetylated piperazinyl amide into rhodamine conjugates differing in their alkyl moieties. These conjugates were submitted to cytotoxicity assays employing a panel of human tumor cell lines. These conjugates held high cytotoxicity but also some selectivity especially for A2780 cells. Thereby, a propyl substituted rhodamine conjugate showed EC50 values as low as EC50 = 0.01 μM and was approx. 15 times more cytotoxic for the cancer cells than for non-malignant fibroblasts (NIH 3 T3). Cytotoxicity obviously parallels the lipophilicity of the residue and suggests - since the compounds act as mitocanes - an interaction of the conjugates with the inner mitochondrial membrane