A new cytotoxic bufadienolide from Chinese medicine Chansu

A new cytotoxic bufadienolide was isolated from the traditional Chinese medicine-Chansu. The structure of new compound was elucidated on the basis of spectral methods including 2D NMR. And it showed strong in vitro cytotoxic activity against Hela cells with IC50 of 8.06 × 10^-2μmol/L.

Simultaneous Determination of Bufadienolides and Qualitative Evaluation for Venenum Bufonis by High Performance Liquid Chromatography

A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides（resibufogenin, einobufagin, cinobufaginol, arenobufagin, bufalin, bufotalin, gamabufotalin, cinobufotalin, ψ-bufaranogin, desacetylcinobufagin, telocinobufagin and resibufogenol） in Venenum Bufonis. The chromatographic separation was performed on a Dikma C18 analytical column via gradient elution with an aqueous solution of acetonitrile and 0.3% acetic acid at a flow rate of 0.8 mL/min. The method was validated to be acceptable in consideration of linearity（r2 〉 0.9992） and recovery（ranged from 98.9% to 102.0%）. The limits of detection of the bufadienolides were from 0.48 ng for bufalin to 6.00 ng for cinobufotalin. The intra-day and inter-day precisions of the method were evaluated and were less than 3.0%. The method was successfully used to analyze 19 batches of Venenum Bufonis, and the similarity values between batches were calculated by Similarity Evaluation System for Chromatographic Fingerprint of TCM（Version 2004A, Chinese Pharmacopoeia Committee, Beijing）. The results show that the contents of bufadienolides in the medicine and the similarity values based on these bufadienolides varied significantly from batch to batch. This proposed method could be utilized to qualify and control Venenum Bufonis to ensure its safety and efficacy in application.

An integrated strategy for comprehensive characterization of metabolites and metabolic profiles of bufadienolides from Venenum Bufonis in rats

Comprehensive characterization of metabolites and metabolic profiles in plasma has considerable significance in determining the efficacy and safety of traditional Chinese medicine(TCM)in vivo.However,this process is usually hindered by the insufficient characteristic fragments of metabolites,ubiquitous matrix interference,and complicated screening and identification procedures for metabolites.In this study,an effective strategy was established to systematically characterize the metabolites,deduce the metabolic pathways,and describe the metabolic profiles of bufadienolides isolated from Venenum Bufonis in vivo.The strategy was divided into five steps.First,the blank and test plasma samples were injected into an ultra-high performance liquid chromatography/linear trap quadrupole-orbitrap-mass spectrometry(MS)system in the full scan mode continuously five times to screen for valid matrix compounds and metabolites.Second,an extension-mass defect filter model was established to obtain the targeted precursor ions of the list of bufadienolide metabolites,which reduced approximately 39%of the interfering ions.Third,an acquisition model was developed and used to trigger more tandem MS(MS/MS)fragments of precursor ions based on the targeted ion list.The acquisition mode enhanced the acquisition capability by approximately four times than that of the regular data-dependent acquisition mode.Fourth,the acquired data were imported into Compound Discoverer software for identification of metabolites with metabolic network prediction.The main in vivo metabolic pathways of bufadienolides were elucidated.A total of 147 metabolites were characterized,and the main biotransformation reactions of bufadienolides were hydroxylation,dihydroxylation,and isomerization.Finally,the main prototype bufadienolides in plasma at different time points were determined using LC-MS/MS,and the metabolic profiles were clearly identified.This strategy could be widely used to elucidate the metabolic profiles of TCM preparations or Chinese patent medicines in vivo and provide critical data for rational drug use.

A new bufadienolide with cytotoxic activity from the Chinese traditional drug Ch'an Su

AIM: To study the bufadienolides in the Chinese traditional drug "Ch'an Su" and their cytotoxic activity. METHOD: Various chromatographic techniques were used to isolate the constituents, and their structures were elucidated through physical and spectroscopic data. RESULTS: Twenty compounds were isolated, and eighteen were evaluated in vitro for their cytotoxic activity against A-549 and K-562 cells. CONCLUSION: Compound 1(bufalin 3β-acrylic ester) was a new bufadienolide and exhibited the most potent activity against the two tumor cell lines with IC50 values of 7.16 and 6.83 nmol·L–1. The relationships between structure and activity are discussed.

New cytotoxic C-3 dehydrated bufadienolides from the venom of Bufo bufo gargarizans

Three new C-3 dehydrated bufadienolides were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated as 5β,12β-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide （1）, 5β,12β- 12,14-dihydroxy-11 -oxobufa-2,20,22-trienolide （2）, and 5β,12β-12,14-dihydroxy-11 -oxobufa-2,20,22- trienolide （3） on the basis of extensive spectroscopic analysis, especially 1D NMR and 2D NMR data. In addition, all three compounds were tested for their cytotoxic activities against A549 and HepG2 cancer cell lines. Compounds 2 and 3 showed significant cytotoxicities with IC50 values less than 10 μmol/L on both cancer cells.

ISOLATION AND IDENTIFICATION OF CYTOTOXIC COMPONENTS FROM BRYOPHYLLUM PINNATUM

A potent cytotoxic bufadienolide orthoacetate has been Isolated from Bryophyllum pinnatum. Baaed on spectral study methods, its structure was identified as bersaldegenin 1,3, 5-orthoacetate.

Advancement in research of anti-cancer effects of toad venom(ChanSu) and perspectives

Toad venom, called as Chan Su in China, is a widely used traditional Chinese medicine(TCM) whose active components are mainly bufadienolides. Chan Su could exhibit cardiotonic, anti-microbial, anti-inflammatory and, most importantly, anti-cancer effects. In the present review, reports about the in vitro, in vivo and clinical anti-cancer effects of Chan Su or its representative component, bufalin, were summarized.And, reported anti-cancer mechanisms of cardenolides, structure analogues of bufadienolides, were also introduced. Based on the results got from research of Chan Su/bufalin and the results from cardenolides, possible signal network related to the anti-cancer effects of Chan Su/bufalin was predicted. Furthermore, future potential use of Chan Su in anti-cancer therapy was discussed.

Do predators prefer toxic animals?A case of chemical discrimination by an Asian snake that sequesters firefly toxins

Several Asian natricine snakes of the genus Rhabdophis feed on toads and sequester steroidal cardiac toxins known as bufadienolides(BDs)from them.A recent study revealed that species of the Rhabdophis nuchalis Group ingest lampyrine fireflies to sequester BDs.Although several species of fireflies are distributed in the habitat of the R.nuchalis Group,only lampyrine fireflies,which have BDs,are included in the diet of these snakes.Thus,we hypothesized that the R.nuchalis Group chemically distinguishes fireflies that have BDs from those that do not have BDs.We also predicted that the R.nuchalis Group detects BDs as the chemical cue of toxin source.To test these predictions,we conducted 3 behavioral experiments using Rhabdophis chiwen,which belongs to the R.nuchalis Group.In the first experiment,R.chiwen showed a moderate tongue flicking response to cinobufagin,a compound of BDs.On the other hand,the snake showed a higher response to the chemical stimuli of lampyrine fireflies(BD fireflies)than those of lucioline fireflies(non-BD fireflies).In the second experiment,in which we provided live BD and non-BD fireflies,the snake voluntarily consumed only the former.In the third,a Y-maze experiment,the snake tended to select the chemical trail of BD fireflies more frequently than that of non-BD fireflies.These results demonstrated that R.chiwen discriminates BD fireflies from non-BD fireflies,but the prediction that BDs are involved in this discrimination was not fully supported.To identify the proximate mechanisms of the recognition of novel toxic prey in the R.nuchalis Group,further investigation is necessary.

Chemical constituents from Kalanchoe hybrida and their cytotoxicity

Objective：Kalanchoe hybrida（Crassulaceae）is naturalized throughout all the island of Taiwan in China.The preliminary bioassay-guided fractionation of the crude extract of K.hybrida exhibited that the chloroform and n-butanol fractions possessed potent cytotoxicity against MCF-7,NCI-H460,and SF-268 tumor cell lines at 50μg/m L concentration.Therefore,K.hybrida was selected as a target and the chemical constituents from the chloroform and n-butanol fractions of the crude extracts of K.hybrida were identified.The potential constituents were examined for their cytotoxicity against the tumor cell lines.Methods：A combination of conventional chromatographic techniques was performed on the crude extract of K.hybrida.The chemical structures of the purified constituents were identified on the basis of spectroscopic and spectrometric analysis.Results：The purification results had led to the characterization of totally 37 compounds.The isolated compounds 1,2,and 4–12 were examined for their cytotoxicity in vitro,and bufadienolides 4–8 and flavonol glycoside 11 displayed significant cytotoxicity towards all the tested tumor cell lines among these tested compounds.Conclusion：The results indicated that these principles should be responsible for the bioactivity of corresponding partial fractions.The potential constituents could be further investigated to explore the new natural lead drugs.