Ginsenoside Rb₁ (or Ginsenoside Rb1 or GRb₁ or GRb1) is a chemical compound belonging to the

ginsenoside Ginsenosides or panaxosides are a class of natural product steroid glycosides and triterpene saponins. Compounds in this family are found almost exclusively in the plant genus ''Panax'' (ginseng), which has a long history of use in traditional med ...

family. Like other ginsenosides, it is found in the plant genus ''

Panax The ''Panax'' (ginseng) genus belongs to the Araliaceae (ivy) Family (biology), family. ''Panax'' species are characterized by the presence of ginsenosides and gintonin. ''Panax'' is one of approximately 60 plant genera with a classical disjunct ...

'' (

ginseng Ginseng () is the root of plants in the genus ''Panax'', such as South China ginseng (''Panax notoginseng, P. notoginseng''), Korean ginseng (''Panax ginseng, P. ginseng''), and American ginseng (''American ginseng, P. quinquefol ...

), and has a variety of potential health effects including

anticarcinogen An anticarcinogen (also known as a carcinopreventive agent) is a substance that counteracts the effects of a carcinogen or inhibits the development of cancer. Anticarcinogens are different from anticarcinoma agents (also known as anticancer or ant ...

ic,

immunomodulatory Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as ''activation immunotherapies,'' while immunothera ...

, anti‐inflammatory, antiallergic, antiatherosclerotic,

antihypertensive Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke, heart failure, kidney failure and myocardial infa ...

, and

antidiabetic Drugs used in diabetes treat types of diabetes mellitus by decreasing glucose levels in the blood. With the exception of insulin, most GLP-1 receptor agonists ( liraglutide, exenatide, and others), and pramlintide, all diabetes medications a ...

effects as well as antistress activity and effects on the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

Pharmacological effects

A 1998 study by

Seoul National University Seoul National University (SNU; ) is a public university, public research university in Seoul, South Korea. It is one of the SKY (universities), SKY universities and a part of the Flagship Korean National Universities. The university's main c ...

reported that GRb₁ and GRg₃ (ginsenosides Rb₁ and Rg₃) significantly attenuated glutamate-induced neurotoxicity by inhibiting the overproduction of

nitric oxide synthase Nitric oxide synthases (NOSs) are a family of enzymes catalyzing the production of nitric oxide (NO) from L-arginine. NO is an important cellular signaling molecule. It helps modulate vascular tone, insulin secretion, airway tone, and peristal ...

among some other findings regarding their neuroprotective properties. In 2002, the Laboratory for Cancer Research in

Rutgers University Rutgers University ( ), officially Rutgers, The State University of New Jersey, is a Public university, public land-grant research university consisting of three campuses in New Jersey. Chartered in 1766, Rutgers was originally called Queen's C ...

showed that GRb₁ and GRg₁ have neuroprotective effect for

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s, while ginsenoside Re did not exhibit any activity. GRb₁ and GRg₁ are proposed to represent potentially effective

therapeutic agents Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the m ...

for

spinal cord injuries A spinal cord injury (SCI) is damage to the spinal cord that causes temporary or permanent changes in its function. It is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. Symptoms of ...

. The protection that GRg₁ (ginsenoside Rg₁) and GRb₁ offer against

Alzheimer’s disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

symptoms in mice was first published by researchers in 2015. The GRg₁ affected three metabolic pathways: the

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

of lecithin,

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s and

sphingolipid Sphingolipids are a class of lipids containing a backbone of sphingoid bases, which are a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sp ...

s, while GRb₁ treatment affected

lecithin Lecithin ( ; from the Ancient Greek "yolk") is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues which are amphiphilic – they attract both water and fatty substances (and so ar ...

and amino acid metabolism. It was reported in 2017 that GRb₁ improved cardiac function and remodelling in heart failure in mice. The treatment of H-ginsenoside Rb₁ potentially attenuated

cardiac hypertrophy Ventricular hypertrophy (VH) is thickening of the walls of a ventricle (lower chamber) of the heart. Although left ventricular hypertrophy (LVH) is more common, right ventricular hypertrophy (RVH), as well as concurrent hypertrophy of both ventr ...

and

myocardial fibrosis Cardiac fibrosis commonly refers to the excess deposition of extracellular matrix in the cardiac muscle, but the term may also refer to an abnormal thickening of the heart valves due to inappropriate proliferation of cardiac fibroblasts. Fibrotic c ...

Proposed biosynthesis

The biosynthesis of GRb₁ in ''Panax ginseng'' starts from

farnesyl diphosphate Farnesyl pyrophosphate (FPP), also known as farnesyl diphosphate (FDP), is the precursor to all sesquiterpenes, which comprises thousands of compounds. These include all sesquiterpenes as well as sterols and carotenoids. It is also used in the syn ...

(FPP), which is converted to

squalene Squalene is an organic compound. It is a triterpene with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as '' Squalus'' is a genus of sharks). ...

with

squalene synthase Squalene synthase (SQS) or farnesyl-diphosphate:farnesyl-diphosphate farnesyl transferase is an enzyme localized to the membrane of the endoplasmic reticulum. SQS participates in the terpenoid, isoprenoid biosynthetic pathway, catalyzing a two-s ...

(SQS), then to

2,3-oxidosqualene (''S'')-2,3-Oxidosqualene ((''S'')-2,3-epoxysqualene) is an intermediate in the synthesis of the cell membrane sterol precursors lanosterol and cycloartenol, as well as saponins. It is formed when squalene is oxidized by the enzyme squale ...

with squalene epoxidase (SE). The 2,3-oxidasqualene is then converted to dammarenediol-II by

cyclization A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where ...

, with dammarenediol-II synthase (DS) as the

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

. The dammarenediol-II is converted to

protopanaxadiol Protopanaxadiol (PPD) is an organic compound that is an aglycone of ginsenosides, a group of steroid glycosides. It is a dammarane-type tetracyclic terpene sapogenin found in ginseng (''Panax ginseng'') and in notoginseng (''Panax pseudoginseng ...

and then to ginsenoside Rd. Finally, GRb₁ is synthesized from ginsenoside Rd, catalysed by UDPG:ginsenoside Rd

glucosyltransferase Glucosyltransferases are a type of glycosyltransferase that enable the transfer of glucose. Examples include: * glycogen synthase * glycogen phosphorylase Glycogen phosphorylase is one of the phosphorylase enzymes (). Glycogen phosphorylase c ...

(UGRdGT), a biosynthetic

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

of GRb₁ first discovered in 2005.''''

References

{{reflist Biosynthesis Triterpene glycosides