Geraniin is a dehydroellagitannin found in geraniums. It is found for instance in Geranium thunbergii, 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).Rapid isolation of geraniin from Nephelium lappaceum rind waste and its anti-hyperglycemic activity. Uma D. Palanisamy, Lai Teng Ling, Thamilvaani Manaharan, and David Appleton, Food Chemistry, 1 July 2011, Volume 127, Issue 1, Pages 21–27,
It mediates apoptosis by cleavage of focal adhesion kinase 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, and NF-κB in ovarian cancer cells. Wang X, et al. Geraniin suppresses ovarian cancer growth through inhibition of NF-κB activation and downregulation of Mcl-1 expression. J Biochem Mol Toxicol. 2017 Sep;31(9)
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 unit, one modified hexahydroxydiphenic acid unit (dehydrohexahydroxydiphenic acid or DHHDP) and one gallic acid unit linked to a glucose 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-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