Biomedical subjects

Rob Verpoorte

Publications and source records attributed to Rob Verpoorte.

8 recordsLinked to original sources

PubMed2006

Structure elucidation of the tetrahydrocannabinol complex with randomly methylated beta-cyclodextrin.

The low aqueous solubility of the bioactive cannabinoid tetrahydrocannabinol (THC) is a serious obstacle for the development of more efficient administration forms. In this study the aqueous solubility of THC was tested in the presence of alpha-, beta- and gamma-CD, and randomly methylated beta-CD (RAMEB). It was found that only RAMEB was able to increase the aqueous solubility of THC to a significant level. A THC concentration of about 14 mg/ml was reached by using a 24% (187 mM) RAMEB solution, which means an increase in solubility of four orders of magnitude. The resulting THC/RAMEB complex was investigated through phase-solubility analysis, complemented by (1)H NMR, NOESY- and UV-studies in order to obtain details on the stoichiometry, geometry and thermodynamics of the complexation. The binding ratio of THC to CD was found to be 2:1, with the second THC molecule bound by non-inclusion interactions. Based on the obtained results a model for the complex structure is presented. Stability of the complex under laboratory room conditions was tested up to 8 weeks. Results show that complexation with RAMEB seems to be promising for the development of water-based THC formulations.

Dronabinol↗

PubMed2006

Setting standards!

Explore the source record for details and available documents.

Anti-Infective Agents↗

PubMed2006

Evaluation of a vaporizing device (Volcano) for the pulmonary administration of tetrahydrocannabinol.

What is currently needed for optimal use of medicinal cannabinoids is a feasible, nonsmoked, rapid-onset delivery system. Cannabis "vaporization" is a technique aimed at suppressing irritating respiratory toxins by heating cannabis to a temperature where active cannabinoid vapors form, but below the point of combustion where smoke and associated toxins are produced. The goal of this study was to evaluate the performance of the Volcano vaporizer in terms of reproducible delivery of the bioactive cannabinoid tetrahydrocannabinol (THC) by using pure cannabinoid preparations, so that it could be used in a clinical trial. By changing parameters such as temperature setting, type of evaporation sample and balloon volume, the vaporization of THC was systematically improved to its maximum, while preventing the formation of breakdown products of THC, such as cannabinol or delta-8-THC. Inter- and intra-device variability was tested as well as relationship between loaded- and delivered dose. It was found that an average of about 54% of loaded THC was delivered into the balloon of the vaporizer, in a reproducible manner. When the vaporizer was used for clinical administration of inhaled THC, it was found that on average 35% of inhaled THC was directly exhaled again. Our results show that with the Volcano a safe and effective cannabinoid delivery system seems to be available to patients. The final pulmonal uptake of THC is comparable to the smoking of cannabis, while avoiding the respiratory disadvantages of smoking.

Administration, Inhalation↗

PubMed2006

Activity of quinones from teak (Tectona grandis) on fungal cell wall stress.

Teak ( Tectona grandis L.f., Verbenaceae) sawdust extract inhibited the growth of Aspergillus niger. Centrifugal partition chromatography was used to isolate the active compounds. By (1)H-NMR the active compounds were identified as deoxylapachol and tectoquinone. Two A. niger transgenic strains which show induction of 1,3 -alpha-D-glucan synthase were used as a cell wall damage model. The result showed that deoxylapachol from T. grandis extract induced fungal cell wall stress.

Antifungal Agents↗

PubMed2005

Metabolomics in the context of systems biology: bridging traditional Chinese medicine and molecular pharmacology.

The introduction of the concept of systems biology, enabling the study of living systems from a holistic perspective based on the profiling of a multitude of biochemical components, opens up a unique and novel opportunity to reinvestigate natural products. In the study of their bioactivity, the necessary reductionistic approach on single active components has been successful in the discovery of new medicines, but at the same time the synergetic effects of components were lost. Systems biology, and especially metabolomics, is the ultimate phenotyping. It opens up the possibility of studying the effect of complex mixtures, such as those used in Traditional Chinese Medicine, in complex biological systems; abridging it with molecular pharmacology. This approach is considered to have the potential to revolutionize natural product research and to advance the development of scientific based herbal medicine.

Drugs, Chinese Herbal↗

PubMed2005

Methyljasmonate accelerates catabolism of monoterpenoid indole alkaloids in Catharanthus roseus during leaf processing.

Variations in alkaloid pattern during drying of leaves (leaf processing) showed that treatment with methyljasmonate can induce formation of bisindole alkaloids as a result of catabolism of the monomeric alkaloids catharanthine and vindoline. A two-fold increase in 3',4'-anhydrovinblastine was shown in treated leaves especially from day 8 until day 21. Serpentine also increased in the same period under the treatment as a catabolic product of ajmalicine. Basic peroxidases that are responsible for the formation of anhydrovinblastine and serpentine showed high activity at days 8 and 21 in treated leaves, causing the increase in anhydrovinblastine and serpentine.

Acetates↗

PubMed2004

Alkaloid accumulation in Catharanthus roseus cell suspension cultures fed with stemmadenine.

Feeding stemmadenine to Catharanthus roseus cell suspension culture resulted in the accumulation of catharanthine, tabersonine and condylocarpine. Condylocarpine is not an intermediate in the pathway to catharanthine or tabersonine when it is fed to the cultures. The results support the hypothesis that stemmadenine is an intermediate in the pathway to catharanthine and tabersonine.

Alkaloids↗

PubMed2002

Tracheospasmolytic activity of viteosin-A and vitexicarpin isolated from vitex trifolia.

The n-hexane extract that has shown activity in the tracheospasmolytic bioassay was fractionated by solvent extraction and from the major active fraction two compounds were isolated and identified as viteosin-A and vitexicarpin. These compounds blocked spontaneous contraction of isolated male guinea pig trachea induced by histamine; however only vitexicarpin was active in a model using sensitized guinea pig trachea stimulated by ovalbumin up to minimum dose of 1.3 x 10(-5) M. The result suggests that vitexicarpin is able to block effects of histamine released from sensitized mast cells possibly by stabilizing the mast cells membrane function.

Animals↗