Rhein

Synonym(s):Rheic acid;Rhubarb yellow;4,5-Dihydroxyanthraquinone-2-carboxylic acid;9,10-Dihydro-4,5-dihydroxy-9,10-dioxo-2-anthracenecarboxylic acid;Cassic acid

CAS NO.：478-43-3
Empirical Formula: C15H8O6
Molecular Weight: 284.22
MDL number: MFCD00009618
EINECS: 207-521-4
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 00:24:37

What is Rhein?

The Uses of Rhein

Rhein is used to inhibit growth factor beta-1 induced plasminogen activator inhibitor-1 in endothelial cells. It acts as an antibacterial agent against Staphylococcus aureus. It is also used as a laxative. Further, it is employed as a pharmaceutical intermediate.

The Uses of Rhein

Found in the free state and as glucoside in Rheum spp, Polygonaceae (rhubarb) and in Senna leaves. A potential antioxidant resource: endophytic fungi from medicinal plants.

The Uses of Rhein

Rhein was used to induce necrosis-apoptosis switch in injured pancreatic acinar cells.

Definition

ChEBI: Rhein is a dihydroxyanthraquinone.

General Description

Yellow needles (from methanol) or yellow-brown powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Rhein forms a red potassium salt and a pink sodium salt.

Hazard

Low toxicity by ingestion.

Fire Hazard

Flash point data for Rhein are not available; however, Rhein is probably combustible.

Biochem/physiol Actions

Constituent that is enriched in rhubarb with anti-inflammatory, anti-osteoarthritic, and anti-cancer activity. It reduces IL-1β production and secretion, caspase-3 activity, inducible nitric oxide synthase activity, and phosphorylation of c-Jun and c-Jun NH2-terminal kinase (JNK).

Safety Profile

A poison by intravenous route. Low toxicity by ingestion. When heated to decomposition it emits acrid smoke and irritating vapors.

Storage

Store at -20°C

Properties of Rhein

Melting point:	≥300 °C (lit.)
Boiling point:	346.72°C (rough estimate)
Density	1.3269 (rough estimate)
refractive index	1.4413 (estimate)
storage temp.	2-8°C
solubility	DMSO (Slightly), Methanol (Slightly)
form	neat
pka	3.17±0.20(Predicted)
form	Solid
color	Yellow to Dark Orange
Water Solubility	<0.1 g/100 mL at 17 ºC
λmax	432nm(MeOH)(lit.)
Merck	14,8176
BRN	2222155
Stability:	Hygroscopic
CAS DataBase Reference	478-43-3(CAS DataBase Reference)
EPA Substance Registry System	2-Anthracenecarboxylic acid, 9,10-dihydro-4,5-dihydroxy-9,10-dioxo- (478-43-3)

Safety information for Rhein

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H315:Skin corrosion/irritation H319:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P264:Wash hands thoroughly after handling. P264:Wash skin thouroughly after handling. P271:Use only outdoors or in a well-ventilated area. P280:Wear protective gloves/protective clothing/eye protection/face protection. P302+P352:IF ON SKIN: wash with plenty of soap and water. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.