Geraniin is a dehydro
ellagitannin
The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl ...
found in
geraniums.
It is found for instance in ''
Geranium thunbergii
''Geranium thunbergii'' (Thunberg's geranium) is a cranesbill species that iscommonly known as Japanese geranium or Japanese cranesbill. It is one of the most popular folk medicines and also an official antidiarrheic drug in Japan.Structure of ...
'', which is one of the most popular folk medicines and also an official antidiarrheic drug in Japan. It can also be found in the rind of ''
Nephelium lappaceum
Rambutan (; taxonomic name: ''Nephelium lappaceum'') is a medium-sized tropical tree in the family Sapindaceae. The name also refers to the edible fruit produced by this tree. The rambutan is native to Southeast Asia. It is closely related to se ...
'' (rambutan).
It mediates
apoptosis by cleavage of
focal adhesion kinase
PTK2 protein tyrosine kinase 2 (PTK2), also known as focal adhesion kinase (FAK), is a protein that, in humans, is encoded by the ''PTK2'' gene. PTK2 is a focal adhesion-associated protein kinase involved in cellular adhesion (how cells stick to ...
through up-regulation of
Fas ligand expression in human
melanoma cells.
[
Geraniin has also been shown to possess immunomodularity properties, as it inhibits ]tumor necrosis factor-alpha
Tumor necrosis factor (TNF, cachexin, or cachectin; formerly known as tumor necrosis factor alpha or TNF-α) is an adipokine and a cytokine. TNF is a member of the TNF superfamily, which consists of various transmembrane proteins with a homolog ...
, and NF-κB
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular ...
in ovarian cancer cells.
Geraniin was studied for its anticancer activity and shown to target apoptosis via inactivation of PI3K/Akt/mTOR signaling pathway involving NF-κB when treated against HT-29 human colorectal adenocarcinoma cells.
It is formed with one hexahydroxydiphenic acid
Hexahydroxydiphenic acid is an organic compound with the formula HO)3C6HCO2Hsub>2. It is the oxidatively coupled derivative of gallic acid It is a white solid, although samples are typically brown owing to oxidation.
left, 142px, Ellagic acid. ...
unit, one modified hexahydroxydiphenic acid unit ( dehydrohexahydroxydiphenic acid or DHHDP) and one gallic acid
Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. I ...
unit linked to a glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
molecule. It is forming an equilibrium mixture of six-membered hemi-ketal and five-membered hemi-ketal forms.
Chebulagic acid is formed from geraniin through a glutathione
Glutathione (GSH, ) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, pe ...
-mediated conversion.[Glutathione-mediated conversion of the ellagitannin geraniin into chebulagic acid. Tanaka T, Kouno I and Nonaka G.I, Chemical and pharmaceutical bulletin, 1996, volume 44, no 1, pages 34-40, ]
References
{{ellagitannin
Dibenzofurans
Ellagitannins