Chrysophanol anthrone

Aromatic natural products of polyketide origin are less prevalent in plants compared with microorganisms. The majority of the plant constituents that contain aromatic stmctures are known to arise from the shikimate pathway (see below). Unlike those derived from the shikimate pathway, aromatic products of the polyketide pathway invariably contain a meta oxygenation pattern because of their origin from the cyclization of polyketides. Phenolic compounds such as chrysophanol-anthrone (Bl), and emodin-anthrone (B2), and the anthraquinones, aloe-emodin (B3) and emodin (B4) (Fig. 2), are products of the polyketide pathway and are found to occur in some plants of the genera Cassia (Leguminosae) (21), Rhamnus (Rhamnaceae) (22), and Aloe (Liliaceae) (23). The dimer of emodin-anthrone (B2), namely hypericin, (B5) is a constituent of the antidepressant herbal supplement, St. John s wort (Hypericumperforatum, Hy-pericaceae) (24). 

The competitive incorporation of chrysophanol (78) and chrysophanol-anthrone (79) was carried out by using different isotopes ( H and " C) for the two precursors. It was shown that chrysophanol and chrysophanolanthrone differ slightly in their specific incorporations (4.14 and 3.71%, respectively). 

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. 

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