Biomaterial Database

Galloyl esters from rhubarb are potent inhibitors of squalene epoxidase, a key enzyme in cholesterol biosynthesis. 2000

I Abe, and T Seki, and H Noguchi, and Y Kashiwada

Galloyl glucoses and galloyl proanthocyanidins obtained from rhubarb (Rhei Rhizoma, Rheum palmatum L., Polygonaceae); e.g. 1,2,6-tri-O-galloyl-beta-D-glucose (IC50 = 0.63 microM), 1,6-di-O-galloyl-2-O-cinnamoyl-beta-D-glucose (IC50 = 0.58 microM), procyanidin B-2 3,3'-di-O-gallate (IC50 = 0.54 microM), and procyanidin B-5 3,3'-di-O-gallate (IC50 = 0.55 microM), were found to be potent inhibitors of rat squalene epoxidase (SE). The inhibition at submicromolar level was far more potent than that of chemically synthesized substrate analogs. It was demonstrated for the first time that the cholesterol-lowering effect of rhubarb may be attributed to the potent inhibition activities of SE, a rate-limiting enzyme of cholesterol biogenesis.

UI	MeSH Term	Description	Entries
D010105	Oxygenases	Oxidases that specifically introduce DIOXYGEN-derived oxygen atoms into a variety of organic molecules.	Oxygenase
D010946	Plants, Medicinal	Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.	Herbs, Medicinal,Medicinal Herbs,Healing Plants,Medicinal Plants,Pharmaceutical Plants,Healing Plant,Herb, Medicinal,Medicinal Herb,Medicinal Plant,Pharmaceutical Plant,Plant, Healing,Plant, Medicinal,Plant, Pharmaceutical,Plants, Healing,Plants, Pharmaceutical
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D004952	Esters	Compounds derived from organic or inorganic acids in which at least one hydroxyl group is replaced by an –O-alkyl or another organic group. They can be represented by the structure formula RCOOR’ and are usually formed by the reaction between an acid and an alcohol with elimination of water.	Ester
D005707	Gallic Acid	A colorless or slightly yellow crystalline compound obtained from nutgalls. It is used in photography, pharmaceuticals, and as an analytical reagent.	3,4,5-Trihydroxybenzoic Acid,Acid, Gallic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012250	Rheum	A plant genus of the family POLYGONACEAE. Members contain chrysophanic acid, rhein, EMODIN, and other ANTHRAQUINONES. The roots were formerly used as PURGATIVES.	Rhubarb,Chinese Rhubarb,Da Huang,Rheum officinale,Rheum rhaponticum,Rheum tanguticum,Huang, Da,Rhubarb, Chinese
D050603	Squalene Monooxygenase	The second enzyme in the committed pathway for CHOLESTEROL biosynthesis, this enzyme catalyzes the first oxygenation step in the biosynthesis of STEROLS and is thought to be a rate limiting enzyme in this pathway. Specifically, this enzyme catalyzes the conversion of SQUALENE to (S)-squalene-2,3-epoxide.	Squalene Epoxidase,Squalene Monooxygenase (2,3-Epoxidizing),Epoxidase, Squalene,Monooxygenase, Squalene