Ranunculin is a

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

found in many members of the

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

, including species of

Helleborus Commonly known as hellebores (), the Eurasian genus ''Helleborus'' consists of approximately 20 species of herbaceous or evergreen perennial flowering plants in the family Ranunculaceae, within which it gave its name to the tribe of Hellebo ...

Anemone ''Anemone'' () is a genus of flowering plants in the buttercup family Ranunculaceae. Plants of the genus are commonly called windflowers. They are native to the temperate and subtropical regions of all regions except Australia, New Zealand, and ...

Clematis ''Clematis'' is a genus of about 380 species within the buttercup family, Ranunculaceae. Their garden hybrids and cultivars have been popular among gardeners, beginning with ''Clematis'' 'Jackmanii', a garden staple since 1862; more cultivars ...

and most commonly

Ranunculus ''Ranunculus'' is a large genus of about 1750 species of flowering plants in the family Ranunculaceae. Members of the genus are known as buttercups, spearworts and water crowfoots. The genus is distributed worldwide, primarily in temperate an ...

. Glycosides are common in plants, where they serve as defense mechanisms against

herbivores A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

and

microorganisms A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

. When plant cell wall structures are damaged,

glycosidase In biochemistry, glycoside hydrolases (also called glycosidases or glycosyl hydrolases) are a class of enzymes which catalyze the hydrolysis of glycosidic bonds in complex sugars. They are extremely common enzymes, with roles in nature inclu ...

enzymes

hydrolyze Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

the inactive glycoside into its components- a sugar and practically any other molecule, which is called the

aglycone An aglycone (aglycon or genin) is the chemical compound remaining after the glycosyl group on a glycoside is replaced by a hydrogen atom. For example, the aglycone of a cardiac glycoside would be a steroid A steroid is an organic compoun ...

. Ranunculin is a

glucoside A glucoside is a glycoside that is chemically derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. Th ...

, which indicates that

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

is the specific sugar attached its aglycone

protoanemonin Protoanemonin (sometimes called anemonol or ranunculol) is a toxin whose glyosidic precursor ranunculin is found in many plants of the buttercup family (Ranunculaceae). When the plant is wounded or macerated, ranunculin is enzymatically broken ...

Toxicity

Ranunculin is very stable in

acidic An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the ...

medium and fresh plant tissues, but in

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

solution or damaged plant cells is hydrolyzed into the unstable toxin

and glucose.

Protoanemonin release

References

{{reflist, refs= {{cite journal , last1=Bai , first1=Yili , last2=Benn , first2=Michael , last3=Majak , first3=Walter , last4=McDiamid , first4=Ruth , title=Extraction and HPLC Determination of Ranunculin in Species of the Buttercup Family , journal=Journal of Agricultural and Food Chemistr , date=August 15, 1996 , volume=44 , issue=8 , pages=2235-2238 , doi=10.1021/jf950626m , url=https://doi.org/10.1021/jf950626m , access-date=March 28, 2025, url-access=subscription {{cite book, editor1-first=Artur, editor1-last=Berger, editor2-first=Helmut, editor2-last=Wachter, title=Hunnius Pharmazeutisches Wörterbuch, edition=8, publisher=Walter de Gruyter Verlag, year=1998, language=German, isbn=3-11-015793-4 {{cite journal , last1=Moriarty , first1=Robert , last2=Romain , first2=C , last3=Karle , first3=I , last4=Karle , first4=J , title=The Structure of Anemonin , journal=Journal of the American Chemical Society , date=July 1, 1965 , volume=87 , issue=14 , pages=3251-3252 , doi=10.1021/ja01092a047 , url=https://doi.org/10.1021/ja01092a047 , access-date=April 12, 2025, url-access=subscription Glucosides Furanones Ranunculaceae