Gigactonine is a naturally occurring

diterpene Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary ...

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

first isolated from '' Aconitum gigas''. It occurs widely in the

Ranunculaceae Ranunculaceae (, buttercup or crowfoot family; Latin "little frog", from "frog") is a family (biology), family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 spec ...

plant family. The polycyclic ring system of this

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

contains nineteen carbon atoms and one nitrogen atom, which is the same as in

aconitine Aconitine is an alkaloid toxin produced by various plant species belonging to the genus ''Aconitum'' (family Ranunculaceae), commonly known by the names wolfsbane and monkshood. Aconitine is notorious for its toxic properties. Structure and rea ...

and this is reflected in its

preferred IUPAC name In chemical nomenclature, a preferred IUPAC name (PIN) is a unique name, assigned to a chemical substance and preferred among all possible names generated by IUPAC nomenclature. The "preferred IUPAC nomenclature" provides a set of rules for choo ...

History

Gigactonine was reported in 1978 after its isolation from ''Aconitum gigas''. Although a novel structure at that time, it was recognised to be related to known diterpene alkaloids including

delsoline Delsoline and delcosine are two closely related naturally occurring diterpene alkaloids first isolated from '' Delphinium consolida''. They occur widely in the Ranunculaceae plant family. The polycyclic ring system containing nineteen carbon ato ...

, which is

methylated Methylation, in the chemical sciences, is the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These term ...

on its 4-hydroxymethyl

primary alcohol A primary alcohol is an alcohol in which the hydroxy group is bonded to a primary carbon atom. It can also be defined as a molecule containing a “–CH2OH” group. In contrast, a secondary alcohol has a formula “–CHROH” and a tertiary ...

sidechain.

Synthesis

Although individual members of this class of alkaloids have been extensively studied, their chemical complexity has limited the number which have been individually synthesised. Similarly, their full biosynthetic pathway is only known in outline in most cases.

Natural occurrence

Gigactonine has been reported as the main alkaloid in the flowers of ''

Aconitum lycoctonum ''Aconitum lycoctonum'' (wolf's-bane or northern wolf's-bane) is a species of flowering plant in the genus ''Aconitum'', of the family Ranunculaceae, native to much of Europe and northern Asia.Flora Europaea''Aconitum lycoctonum''/ref> It is fou ...

'' and has been isolated from ''

Delphinium ''Delphinium'' is a genus of about 300 species of annual and perennial flowering plants in the family (biology), family Ranunculaceae, native species, native throughout the Northern Hemisphere and also on the high mountains of tropical Africa. T ...

'' including '' Delphinium ajacis'' and other ''

Consolida ''Consolida'' is a genus of about 40 species of annual flowering plants in the family Ranunculaceae, native to western Europe, the Mediterranean and Asia. Phylogenetic studies show that ''Consolida'' is actually an annual clade nested within the ...

'' species in the Ranunculaceae plant family.

Biochemistry

Compounds related to aconitine are widely studied for their properties in biological systems and these have been reviewed. For example, gigactonine has been reported to have

hERG hERG (the human '' Ether-à-go-go''-Related Gene) is a gene () that codes for a protein known as Kv11.1, the alpha subunit of a potassium ion channel. This ion channel (sometimes simply denoted as 'hERG') is best known for its contribution t ...

-inhibiting activity.

References

{{Ion channel modulators Diterpene alkaloids HERG blocker