Bibenzyl Compound Research Articles

Determination of chrysotoxine in rat plasma by liquid chromatography–tandem mass spectrometry and its application to a rat pharmacokinetic study

Chrysotoxine (CTX), a naturally occurring bibenzyl compound isolated from Dendrobium species, has been reported to have neuroprotective effects. To evaluate its pharmacokinetics in rats, a rapid, sensitive and specific high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method has been developed and validated for the quantification of CTX in rat plasma. Samples were pretreated using a simple liquid-liquid extraction with ethyl acetate and the chromatographic separation was performed on a C18 column with acetonitrile-water (90:10, v/v) as the mobile phase. CTX and the internal standard (wogonin) were detected using a tandem mass spectrometer in positive multiple reaction monitoring mode. Method validation revealed excellent linearity over the range 0.5-1000 ng/mL together with satisfactory intra- and inter-day precision, accuracy and recovery. Stability testing showed that CTX spiked into rat plasma was stable for 8 h at room temperature, for up to two weeks at -20 °C, and during three freeze-thaw cycles. Extracted samples were also observed to be stable over 24 h in an auto-sampler. The method was successfully used to investigate the pharmacokinetic profile of CTX after oral (100 mg/kg) and intravenous (25 mg/kg) administration in rats. CTX showed rapid excretion and low bioavailability in rats.

Identification of the metabolites of gigantol in rat urine by ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

Gigantol is a typical bibenzyl compound isolated from Dendrobii Caulis that has been widely used as a medicinal herb in China for the treatment of diabetic cataract, cancer and arteriosclerosis obliterans and as a tonic for stomach nourishment, saliva secretion promotion and fever reduction. However, few studies have been carried out on its in vivo metabolism. In the present study, a rapid and sensitive method based on ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) in positive ion mode was developed and applied to identify the metabolites of gigantol in rat urine after a single oral dose (100 mg/kg). Chromatographic separation was performed on an Acquity UPLC HSS T3 column (100 × 2.1 mm i. d., 1.8 µm) using acetonitrile and 0.1% aqueous formic acid as mobile phases. A total of 11 metabolites were detected and identified as all phase II metabolites. The structures of the metabolites were identified based on the characteristics of their MS, MS(2) data and chromatographic retention times. The results showed that glucuronidation is the principal metabolic pathway of gigantol in rats. The newly identified metabolites are useful to understand the mechanism of elimination of gigantol and, in turn, its effectiveness and toxicity. As far as we know, this is the first attempt to investigate the metabolic fate of gigantol in vivo.

Gigantol, a bibenzyl from Dendrobium draconis, inhibits the migratory behavior of non-small cell lung cancer cells.

Lung cancer is one of the most common causes of cancer death due to its high metastasis potential. The process of cancer migration is an early step that is required for successful metastasis. The discovery and development of natural compounds for cancer therapy have garnered increasing attention in recent years. Gigantol (1) is a bibenzyl compound derived from the Thai orchid, Dendrobium draconis. It exhibits significant cytotoxic activity against several cancer cell lines; however, until recently, the role of 1 on tumor metastasis has not been characterized. This study demonstrates that 1 suppresses the migratory behavior of non-small cell lung cancer H460 cells. Western blot analysis reveals that 1 down-regulates caveolin-1 (Cav-1), activates ATP-dependent tyrosine kinase (phosphorylated Akt at Ser 473), and cell division cycle 42 (Cdc42), thereby suppressing filopodia formation. The inhibitory effect of 1 on cell movement is also exhibited in another lung cancer cell line, H292, but not in normal human keratinocytes (HaCat). The inhibitory activity of 1 on lung cancer migration suggests that this compound may be suitable for further development for the treatment of cancer metastasis.

Chrysotoxine, a novel bibenzyl compound selectively antagonizes MPP+, but not rotenone, neurotoxicity in dopaminergic SH-SY5Y cells

Chrysotoxine is a naturally occurring bibenzyl compound found in medicinal Dendrobium species. We previously reported that chrysotoxine structure-specifically suppressed 6-hydroxydopamine (6-OHDA)-induced dopaminergic cell death. Whether chrysotoxine and other structurally similar bibenzyl compounds could also inhibit the neurotoxicity of 1-methyl-4-phenyl pyridinium (MPP+) and rotenone has not been investigated. We showed herein that chrysotoxine inhibited MPP+, but not rotenone, induced dopaminergic cell death in SH-SY5Y cells. The overproduction of reactive oxygen species (ROS), mitochondrial dysfunction as indexed by the decrease in membrane potential, increase in calcium concentration and NF-κB activation triggered by MPP+ were blocked by chrysotoxine pretreatment. The imbalance between the pro-apoptotic signals (Bax, caspase-3, ERK and p38 MAPK) and the pro-survival signals (Akt/PI3K/GSK-3β) induced by MPP+ was partially or totally rectified by chrysotoxine. The results indicated that ROS inhibition, mitochondria protection, NF-κB modulation and regulation of multiple signals determining cell survival and cell death were involved in the protective effects of chrysotoxine against MPP+ toxicity in SH-SY5Y cells. Given the different toxic profiles of 6-OHDA and MPP+ as compared to rotenone, our results also indicated that DAT inhibition may partially account for the neuroprotective effects of chrysotoxine.

Chrysotoxine, a novel bibenzyl compound, inhibits 6-hydroxydopamine induced apoptosis in SH-SY5Y cells via mitochondria protection and NF-κB modulation

Some naturally occurring bibenzyl compounds have been reported as free radical scavengers. The present study tested our hypothesis that bibenzyl compounds may be neuroprotective against apoptosis induced by the neurotoxins. Five structurally similar bibenzyl derivatives were tested for their protective effect against 6-hydroxydopamine (6-OHDA) induced toxicity in the human neuroblastoma cell line SH-SY5Y. The results showed that one bibenzyl compound, namely chrysotoxine, significantly attenuated 6-OHDA-induced cell death. The subsequent mechanism study demonstrated that chrysotoxine significantly attenuated 6-OHDA-induced apoptosis characterized by DNA fragmentation and nuclear condensation in a dose-dependent manner. 6-OHDA-induced intracellular generation of reactive oxygen species (ROS), activation of p38 MAPK and ERK1/2, and mitochondrial dysfunctions, including the decrease of membrane potential, increase of intracellular free Ca 2+, release of cytochrome c, imbalance of Bax/Bcl-2 ratio and activation of caspase-3 were strikingly attenuated by chrysotoxine pretreatment. Meanwhile, chrysotoxine counteracted NF-κB activation by blocking its translocation to the nucleus, thereby preventing up-regulation of inducible nitric oxide synthase (iNOS) and intracellular NO release. The data provide the first evidence that chrysotoxine protects SH-SY5Y cells against 6-OHDA toxicity possibly through mitochondria protection and NF-κB modulation. Chrysotoxine is thus a candidate for further evaluation of its protection against neurodegeneration in Parkinson's disease.

A new bibenzyl compound from Dendrobium gratiosissmum

A new bibenzyl compound from Dendrobium gratiosissmum

New Bibenzyl Cannabinoid from the New Zealand Liverwort Radula marginata

AbstractFor Abstract see ChemInform Abstract in Full Text.

New bibenzyl cannabinoid from the New Zealand liverwort Radula marginata.

The ether extract of the New Zealand liverwort Radula marginata afforded a new cannabinoid type bibenzyl compound named perrottetinenic acid, and two new bibenzyls, together with a known cannabinoid, perrottetinene. Their structures were established by two dimensional (2D) NMR spectral data. The structure of perrottetinenic acid was a similar to that of Delta(1)-tetrahydrocannabinol, a known hallucinogen. Cannabinoid type bibenzyls have been isolated from liverwort Radula perrottetii, though have not previously been reported from the liverwort R. marginata.

Moscatilin from Dendrobium nobile, a naturally occurring bibenzyl compound with potential antimutagenic activity.

A bibenzyl compound that possesses antimutagenic activity was isolated from the storage stem of Dendrobium nobile. The isolated compound suppressed the expression of the umu gene following the induction of SOS response in Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compound was mainly localized in the n-hexane extract fraction of the processed D. nobile. This n-hexane fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compound. EI-MS and (1)H and (13)C NMR spectroscopy were then used to delineate the structure of the compound that confers the observed antimutagenic activity. Comparison of the obtained spectrum with that found in the literature indicated that moscatilin is the secondary suppressive compound. When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, moscatilin suppressed 85% of the umu gene expression compared to the controls at <0.73 micromol/mL, with an ID(50) value of 0.41 micromol/mL. Additionally, moscatilin was tested for its ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), UV irradiation, 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), benzo[a]pyrene (B[a]P), and aflatoxin B(1) (AFB(1)). With all of the aforementioned chemicals or treatments, moscatilin showed a dramatic reduction in their mutagenic potential. Interestingly, moscatilin almost completely suppressed (97%) the AFB(1)-induced SOS response at concentrations <0.73 micromol/mL, with an ID(50) of 0.08 micromol/mL. Finally, the antimutagenic activities of moscatilin against furylfuramide and Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain. The results those experiments indicated that moscatilin demonstrated a dramatic suppression of the mutagenicity of only Trp-P-1 but not furylfuramide.

Role of stilbenes in the natural durability of wood: Fungicidal structure-activity relationships

The fungicidal bioactivity of a number of ( E)-4-hydroxy-3′- and/or 4 - ́ substituted stilbenes and related analogues was measured against the white-rot fungus Coriolus versicolor and the brown-rot fungi Gloeophyllum trabeum and Poria placenta using the agar plate technique. The bioactivity of didecyldimethylammonium chloride (DDAC), an effective wood preservative, was also determined for comparison purposes. Only DDAC and a (reduced) bibenzyl derivative with a 4′-hydrogen showed fungicidal activity against the white-rot fungus. Against the two brown-rot fungi all stilbenes with a 4′-hydrogen and also a (reduced) bibenzyl compound with a 4′-hydrogen had greater activity than DDAC. A quantitative structure-activity relationship study found that stilbene brown-rot bioactivity was linearly related to hydrophobicity. The results of this study and a review of the prior literature suggests that stilbene phytoalexins may be modified in vivo by partial methylation to further enhance their bioactivity.

The Chemical Constituents of the Liverwort Mylia Nuda

AbstractTwo diterpenoids, (+)‐labda‐7,14‐dien‐13‐ol and (+)‐manoyl oxide, and one bis(bibenzyl) compound, isomarchantin C, were isolated as the major components from the Taiwanese liverwort Mylia nuda. The spectral evidence is discussed in this paper. In addition, several monoterpenes and sesquiterpenes were also identified by GC/MS.

Synergism of free radical initiators with self‐extinguishing additives in vinyl aromatic polymers

AbstractVinyl aromatic polymers such as polystyrene can be made nonflammable by the addition of halogen compounds. The amount of halogen required to make such polymers nonflammable can now be greatly reduced by the addition of small amounts of certain free radical initiators. Normally about 5 phr of acetylene tetrabromide (parts of additive per hundred parts of polymer) must be added to polystyrene to obtain a self‐extinguishing polymer. Only 0.5 phr of acetylene tetrabromide is required if 0.5 phr dicumyl peroxide is added. This synergistic effect has been observed with a series of peroxides, hydroperoxides, azo compounds, quinone imines, benzothiazole sulfenamides, disulfides, and a bibenzyl compound. The synergistic mechanism seems to be based on a series of reactions involving attack of the polymer by the initiator and subsequent reaction between polymer fragments and the halogen compound. The result is a delay in the loss of halogen from the polymer mass and thus a more efficient use of the halogen additive for flame quenching. Known inhibitors of free radical reactions have a detrimental effect on the synergistic mechanism.