Lycorine is a

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

line

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

found in various

Amaryllidaceae The Amaryllidaceae are a family of herbaceous, mainly perennial and bulbous (rarely rhizomatous) flowering plants in the monocot order Asparagales. The family takes its name from the genus ''Amaryllis'' and is commonly known as the amaryllis fa ...

species, such as the cultivated bush lily (''

Clivia miniata ''Clivia miniata'', the Natal lily or bush lily, is a species of flowering plant in the genus ''Clivia'' of the family Amaryllidaceae, native to woodland habitats in South Africa (Eastern Cape, Mpumalanga and KwaZulu-Natal provinces) as well as ...

''), surprise lilies ('' Lycoris''), and daffodils ('' Narcissus''). It may be highly poisonous, or even lethal, when ingested in certain quantities. Regardless, it is sometimes used medicinally, a reason why some groups may harvest the very popular ''Clivia miniata''.

Source

Lycorine is found in different species of ''Amaryllidaceae'' which include flowers and bulbs of daffodil, snowdrop (''Galanthus'') or spider lily (''Lycoris''). Lycorine is the most frequent alkaloid of ''Amaryllidaceae''. The earliest diversification of ''Amaryllidaceae'' was most likely in North Africa and the Iberian peninsula and that lycorine is one of the oldest in the Amaryllidaceae alkaloid biosynthetic pathway.

Mechanism of action

There is currently very little known about the mechanism of lycorine. There are tentative ideas about how lycorine metabolizes due to a study done on

beagle The beagle is a breed of small scent hound, similar in appearance to the much larger foxhound. The beagle was developed primarily for hunting hare, known as beagling. Possessing a great sense of smell and superior tracking instincts, the ...

dogs. Lycorine inhibits

protein synthesis Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside Cell (biology), cells, homeostasis, balancing the loss of cellular proteins (via Proteolysis, degradation or Protein targeting, export) through the product ...

, and may inhibit

ascorbic acid Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...

biosynthesis Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. ...

, although studies on the latter are controversial and inconclusive. Presently, it serves some interest in the study of certain

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...

s, the principal organism on which lycorine is tested. It is known that lycorine weakly inhibits

acetylcholinesterase Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme Enzymes () are proteins that a ...

(AChE) and ascorbic acid biosynthesis. The

IC50 The half maximal inhibitory concentration (IC50) is a measure of the potency of a substance in inhibiting a specific biological or biochemical function. IC50 is a quantitative measure that indicates how much of a particular inhibitory substance ...

of lycorine was found to vary between the different species it can be found in, but a common deduction from the experiments on lycorine was that it had some effect on inhibiting AChE. Lycorine exhibits

cytostatic Cytostasis (cyto – cell; stasis – stoppage) is the inhibition of cell growth and multiplication. Cytostatic refers to a cellular component or medicine that inhibits cell division. Cytostasis is an important prerequisite for structured multic ...

effects by targeting the

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over ...

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...

rather than by inducing

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 cancer cells, though lycorine was found to apoptosis at different stages in a cells cycle.

Biosynthesis

One possible synthesis of lycorine could come from O-Methylnorbelladine, which can be seen in the image to the right.

Toxicity

Poisoning by lycorine most often occurs through the ingestion of daffodil bulbs. Daffodil bulbs are sometimes confused with

onions An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the onion ...

, leading to accidental poisoning. In a study of dosage used on beagle dogs, the first sign of nausea was observed at as little of a dose of 0.5 mg/kg and occurred within a 2.5 hour span. The effective dose to induce

emesis Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteriti ...

in the dogs was seen to be 2.0 mg/kg and lasted no longer than 2.5 hours after administration.

Symptoms

Symptoms of lycorine toxicity are

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

, and

convulsion A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is sometimes used as a s ...

Current research

Lycorine has been seen to have promising biological and pharmacological activities such as antibacterial, antiviral, or anti-inflammatory effects and may have anticancer properties. It has displayed various inhibitory properties towards multiple cancer cell lines that include, lymphoma, carcinoma, multiple myeloma, melanoma, leukemia, human A549 non-small-cell lung cancer, human OE21 esophageal cancer and more. Lycorine has many derivatives used for anti-cancer research such as lycorine hydrochloride (LH) which is a novel anti-ovarian cancer agent, and data has shown that LH effectively inhibited mitotic proliferation of Hey1B cells with very low toxicity. This drug could be used for effective anti-ovarian cancer therapy in the future.

References

External links

* * {{Acetylcholine metabolism and transport modulators Isoquinoline alkaloids Quinoline alkaloids Diols Phenanthridines Plant toxins Acetylcholinesterase inhibitors Protein synthesis inhibitors