Cinobufagin is a cardiotoxic bufanolide

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...

secreted by the Asiatic toad '' Bufo gargarizans''. It has similar effects to digitalis and is used in traditional Chinese medicine.

Isolation and purification

Cinobufagin, as well as other bufadienolides, can be isolated from the traditional Chinese medicine called ChanSu. ChanSu is made from a multitude of chemicals present in Bufo gargarizans secretions. Resibufogenin can be eluted out with silica gel column chromatography, using a 5:1 ratio of

cyclohexane Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohexan ...

to acetone for the solvent in the mobile phase. Subsequently, cinobufagin and bufalin can be separated and purified using an

HPLC High-performance liquid chromatography (HPLC), formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pa ...

column with a 72:28

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

to water solvent. Yang et al. confirmed this method of isolation for cinobufagin with Proton NMR.

Clinical significance

Cinobufagin has been shown to have clinical applications in cancer treatment as well as immunomodulatory and

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

properties. In human adrenocortical cells, cinobufagin inhibits the secretion of aldosterone and cortisol. Cinobufagin is able to inhibit the expression of the StAR protein as well as bind the transcription factor SF-1, which normally binds to the promoter for the StAR gene. This results in less StAR protein product and decreased levels of

aldosterone Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays a c ...

and

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in the adrenal gland ...

synthesis. Cinobufagin first binds to a Ca²⁺/K⁺ plasma membrane

ATPase ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are ...

, subsequently inducing the phosphorylation of extracellular signal-regulated kinases (ERK). Phosphorylated ERK then blocks the SF-1 transcription factor from binding to the promoter region of the StAR gene. Thus, cinobufagin plays important roles in regulation of

synthesis and

gene expression Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. The ...

. It is speculated that cinobufagin may have therapeutic roles in treatment of Cushing’s syndrome and

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

Immunology

In vitro, cinobufagin can stimulate the proliferation of immune cells including splenocytes, peritoneal macrophages, T helper cells and cytotoxic T cells. Additionally cinobufagin can modulate levels of

cytokines Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

produced by immune cells. Exposure to cinobufagin increases levels of interferon gamma and tumor necrosis factor alpha while decreasing overall levels of interleukin 4 and interleukin 10.

Analgesic properties

Cinobufagin has been shown to increase pain threshold levels in mice to thermal and mechanical stimuli. It is thought to trigger increased synthesis of β-END and the up-regulation of the mu opioid receptor in mouse tumor tissue thereby leading to pain relief. β-END binds the mu opioid receptor to cause the

effect.

Interaction with cancer cells and related biochemical pathways

C. elegans can catabolize cinobufagin into five distinct metabolites, each of which has been shown to have cytotoxic effects to HeLa cancer cells. Cinobufagin can induce cell cycle arrest at the G2 and M phases as well as induce

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

in osteosarcoma cells. Potentially, cinobufagin could be used to stop proliferation of osteosarcoma cells as well as to induce

them. At the protein level, cinobufagin treated osteoscarcoma cells showed an increase in the Bax and cleaved-PARP apoptotic proteins, while inhibiting the GSK-3β/ NF-κB signaling pathway. With regards to the induction of

, cinobufagin has been shown to selectively bind K⁺/Na⁺

s in

canine Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** '' Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the ...

kidney cells to trigger a signaling cascade which leads to

caspase Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cystei ...

dependent pathways for

. It is through the activation of

s that Cinobufagin can cause

References

{{Cardiac glycosides Vertebrate toxins Epoxides Bufanolides Secondary alcohols Acetate esters