cinobufagin and bufadienolide

Toads in the family Bufonidae contain bufadienolides in their venom, which are characterized by their chemical diversity and high pharmacological potential. American trypanosomiasis is a neglected disease that affects an estimated 8 million people in tropical and subtropical countries. In this research, we investigated the chemical composition and antitrypanosomal activity of toad venom from

Topics: Amphibian Venoms; Animals; Antineoplastic Agents; Antiprotozoal Agents; Bufanolides; Bufonidae; Cell Line, Tumor; Chlorocebus aethiops; Humans; Mass Spectrometry; MCF-7 Cells; Panama; Skin; Trypanosoma cruzi; Vero Cells

Cinobufagin, a bufadienolide of toad venom of Bufo bufo gargarizans, is used as a cardiotonic, central nervous system (CNS) respiratory agent, as well as an analgesic and anesthetic. However, several research showed that bufadienolide has a few side effects on the CNS, such as breathlessness or coma. Although cinobufagin was shown to display pharmacological effects in various models, the toxic effect of cinobufagin is elusive in brain cell models. The aim of this study was to explore whether cinobufagin affected viability, Ca

Topics: Amphibian Venoms; Animals; Astrocytes; Brain; Bufanolides; Bufo bufo; Calcium; Calcium Signaling; Cell Line; Cell Survival; Cytosol; Endoplasmic Reticulum; Homeostasis; Humans; Neurons; Reactive Oxygen Species; Thapsigargin; Type C Phospholipases

Drying is a useful technique for extending the shelf-life of biological products and enabling long-term storage; however, improper drying can reduce the chemical quality of the products. In this study, we used ultra-performance liquid chromatography-triple quadrupole/mass spectrometry (LC-MS/MS) and multivariate statistical analysis to investigate the effects of four drying methods (V: vacuum-drying at 60°C, F: freeze-drying, H: air-drying at 60°C and R: air-drying at room temperature) on the levels of 36 bufadienolides in toad venom. Vacuum-drying at 60°C produced the highest quality dried toad venom in terms of total bufadienolide content, whereas traditional air-drying at room temperature (RT) to dehydrate the toad venom led to a dramatic loss in free and conjugated bufadienolides, reaching up to 60% and 70%, respectively. Assaying for free bufadienolides ranked the drying methods as V≈F>H>R, whereas assaying for conjugated bufadienolides slightly changed the order to V>F≈H>R. Furthermore, we identified 21 bufadienolides as biomarkers responsible for the decline in the quality of dried toad venom, whose loss varied from 1.5-fold to 100-fold. Of these biomarkers, group I bufadienolides that contain 16-OAc (e.g., cinobufagin and its hydroxyl or arginine ester derivatives) were characteristic components and were reduced to trace levels (loss of more than 10-fold) following traditional air-drying at RT. This might be attributed to the fact that most enzyme-sensitive bufadienolides were biotransformed or degraded at room temperature but were retained using other drying methods.

Topics: Amphibian Venoms; Animals; Biomarkers; Bufanolides; Bufonidae; Chromatography, High Pressure Liquid; Desiccation; Drugs, Chinese Herbal; Freeze Drying; Medicine, Chinese Traditional; Multivariate Analysis; Tandem Mass Spectrometry; Temperature

Microbial transformation of a cytotoxic bufadienolide, cinobufagin (1), was performed by Syncephalastrum racemosum. The six metabolites obtained were identified as 7beta-hydroxycinobufagin ( 2), 12beta-hydroxycinobufagin (3), cinobufotalin (4), 5,12beta-dihydroxycinobufagin (5), 4beta,11alpha-dihydroxycinobufagin (6), and 4beta,12alpha-dihydroxycinobufagin (7), respectively, on the basis of spectroscopic studies. Metabolites 2 and 5-7 were characterized as new compounds, and 2-7 proved to be cytotoxic against Bel-7402 human hepatoma cells.

Topics: Antineoplastic Agents; Biotransformation; Bufanolides; Drug Screening Assays, Antitumor; Humans; Mucorales; Nuclear Magnetic Resonance, Biomolecular

A new bufadienolide, 12-oxo-desacetylcinobufagin, was obtained from the biotransformation of cinobufagin by Alternaria alternata in fairly low yield (0.34%). Its structure was established on the basis of (1)H-NMR, (13)C-NMR, 2D-NMR, and MS spectral data.

Topics: Alternaria; Bufanolides; Molecular Structure

Resibufogenin, cinobufagin, and bufalin are cytotoxic steroids isolated from the Chinese drug Chan'su. Biotransformation of these three bufadienolides by Nocardia sp. NRRL 5646 was investigated. Notably, resibufogenin was converted to 3-acetyl 15beta-hydroxyl bufotalin, via an unprecedented 14beta,15beta-epoxy ring cleavage and a regio-selective acetoxylation. This product showed significantly increased cytotoxic activity. The regio-selective acetylation of the 3-OH was also involved in the other reactions. The structures of metabolites were established by ESI-LC/MS and 2D NMR techniques. The in vitro cytotoxic activities against human cancer cell lines of the substrates and the transformed products were determined by the MTT method and their structure-activity relationship (SAR) was discussed. This investigation provided a useful approach to prepare new bufadienolides and the SAR research.

Topics: Acetylation; Antineoplastic Agents; Biotransformation; Bufanolides; Cell Line, Tumor; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Nocardia; Spectrometry, Mass, Electrospray Ionization; Stereoisomerism; Structure-Activity Relationship

Hydroxylation is an important route to synthesize more hydrophilic compounds of pharmaceutical significance. Microbial hydroxylation offers advantages over chemical means for its high specificity. In this study, a fungal strain Alternaria alternata AS 3.4578 was found to be able to catalyze the specific 12beta-hydroxylation of a variety of cytotoxic bufadienolides. Cinobufagin and resibufogenin could be completely metabolized by A. alternata to generate their 12beta-hydroxylated products in high yields (>90%) within 8 h of incubation. A. alternata could also convert 3-epi-desacetylcinobufagin into 3-epi-12beta-hydroxyl desacetylcinobufagin as the major product (70% yield). C-3 dehydrogenated products were detected in these reactions in fair yields, while their accumulation was relatively slow. The 12beta-hydroxylation of bufadienolides could be significantly inhibited by the substitution of 1beta-, 5-, or 16alpha-hydroxyl groups, and the 14beta,15beta-epoxy ring appeared to be a necessary structural requirement for the specificity. For the biotransformation of bufalin, a 14beta-OH bufadienolide, this reaction was not specific, and accompanied by 7beta-hydroxylation as a parallel and competing metabolic route. The biotransformation products were identified by comparison with authentic samples or tentatively characterized by high-performance liquid chromatography-diode array detection-atmospheric pressure chemical ionization-mass spectrometry analyses.

Topics: Alternaria; Biotransformation; Bufanolides; Cholenes; Chromatography, High Pressure Liquid; Hydroxylation; Kinetics; Spectrometry, Mass, Electrospray Ionization; Substrate Specificity