Anthrone glycosides

Aloin (= Barbaloin) (anthrone glycoside) Abeferox, A. perryi, A. vera (Liliaceae) [leaf], Frangula alnus, Frangula purshiana (Rhamnaceae) PS - eEF-2 [purgative]... 

E Cascarae cortex (5-7) samples are characterized by anthrone glycosides two pairs of yellow fluorescent cascarosides A/B (Rf 0.05-0.15) and cascarosides C/D (R, 0.2-0.25). The cascarosides A/B dominate. The amount of yellow fluorescent aloin (T2), deoxyaloin (R, 0.65) and the red-brown fluorescent aglycones emodin, aloe-emodin, chrysophanol (solvent front) varies. Four blue fluorescent naphthalide derivatives are detectable in the R, range 0.3-0.45. 

C15H10O5. Mr 270.24, orange needles, mp. 223 - 225 °C, uv 430 nm (C2H5OH), soluble in ether, benzene, and hot ethanol. A. is named after the aloe, the concentrated leaf juices of various Aloe species (A. ferox, A. barbadensis, Liliaceae) and occurs additionally in free form and as the corresponding anthrone glycosides in Rhamnus, Rheum, Rumex, and Cassia species. In addition to laxative action it also exhibits an antileukemic effect and is used as starting material for the synthesis of anthracycline antibiotics. 

SoiMiooideo. A group of yellow, homo- and heterodi-meric anthrone glycosides, the aglycones (sennidins) of which are derived from the monomers ifaein and aloe-emodin. 

S. A-G occur in the leaves and fruits of Cassia species (C. senna, C. angustifolia, Fabaceae) and in rhubarb roots, sometimes as oxalyl derivatives (senno-sides E, F). S. are mostly formed from the corresponding anthrone glycosides when the senna leaves are dried. Drugs containing S. are used in therapy for acute constipation (see table, p. 581). 

Should all plant anthraquinones and their derivatives prove to arise by the same route as the anthraquinones of Ruhia tinctoruniy it follows that the medicinally employed purgative properties residing in various anthrone glycosides [119], Hke the adrenergic properties of the ergot alkaloids must now be considered as biological properties of hemiterpenoid derivatives. 

Since the therapeutic applications of reserpine (XLV) as a hypotensive and sedative agent and methoserpidine as a hypotensive agent with greatly reduced sedative properties [251-254], of ergotamine (LVIII) in the treatment of migraine [255], of ergometrine in obstetrics [256], of the anthrone glycosides... 

Polygonum multifolrum Thunb. P. chinensis L. He Shou Wu Huo Tan Mo Cao (Hill buckwheat) (root, stem, leaf) Chrysophenol, emodin, emodin methyl ester, rhein, glycoside rhaphantin, lecithin, parietin, chrysophanic acid, anthron.33-49-54-442 A laxative, detoxicant for boils. Treat neurosis, neurasthenia, insomnia, hypercholesterolemia. 

Adinolfi, M, Lanzetta, R, Marciano, C E, Parrilli, M, Giuliu, A D, A new class of anthraquinone-anthrone-C-glycosides from Asphodelus ramosus tubers. Tetrahedron, Al, 4435-4440, 1991. 

Cascara bark should contain not less than 8.0% of hydroxyanthracenes. Not less than 60% of this mixture must be in the form of cascarosides which are complex mixed O and C glycosides based on the anthrone nucleus. Loss of the O -glucose gives rise to secondary glycosides notably Aloin A-rB, which also are found in Aloes. 

There are two different mechanisms of action for the various anthrones which are seen as the main active metabolites with specific activity on the colon. One mechanism involves the anthrone influencing the motility of the colon through an inactivation of the enzyme Na-r/K-i-ATP-ase which results in an inhibition of the Na-r pump and of Cl-channels in the colonic membrane. This results in the speeding up of transit time through the bowel. A second mechanism involves enhanced fluid secretion into the lumen of the bowel by stimulation of mucous and chloride. The resulting net transfer of fluid into the intestinal lumen triggers reflex defecation. There is a delay of 6-12 hours from administration of the laxative until defecation occurs due to the time taken for the glycosides to reach the colon and be transformed into the active anthrones. 

The use of fresh bark, which contains free anthrones, may cause severe vomiting, intestinal cramping, and possibly spasms (Anonymous, 1996). Therefore, the bark requires either storage for at least 1 yr before use or artificial conversion by heat to allow oxidation of the harsh laxative constituents, the emodin glycosides (anthrones), to less active monomeric forms (Tyler, 1994 Anonymous, 1996). 

Anthrone or its tautomer anthrol or its hydroxy derivatives (i.e., the aglycones) are found to exert purgative effects. However, the anthraquinone glycosides are usually present in several herbal drugs, such as senna, cascara, rhubarb and aloes. 

The glycosidic bond of glycolipids is readily hydrolyzed by acid, and the carbohydrates liberated can be analyzed by instrumental methods, e.g., gas chromatography (GC), liquid chromatography (LC), or colorimetric procedures can be used. In one colorimetric procedure, the total amount of hexose units in a glycolipid can be quantified by reaction with anthrone in concentrated sulfuric acid and determination by the absorbance at 635 nm. 

Anthraquinones are the most widespread group of natural quinones. They occur in higher plants, fungi, lichens and some inseds. Anthraquinones are accompanied by derivatives of anthranol, anthrahydroquinone (9-155) and their oxo forms anthrone and oxanthrone (9-156), which are, as glycosides, precursors of anthraquinone pigments. 

Plants of the genus Aloe contain a reduced form of aloe-emodin as the C-glucoside of the corresponding anthrone, which is called aloin. Lemon yellow aloin is a mixture of two isomers. The major product (S)-aloin or (S)-P-D-glucopyranoside-aloe-emodin is referred to as aloin A (or barbaloin, 9-162), the (l )-isomer is aloin B (isobarbaloin). Related glycosides called aloinosides a and b contain a-L-rhamnopyranose bound by an O-glycosidic bond to the hydroxymethyl group at C-3. 

---