Pseudohypericin structure

St. John s wort and some individual constituents of the preparations have been administered orally, topically, and intravenously in various pharmaceutical formulations, including tinctures, teas, capsules, purified components, and tablets. These botanical preparations of St. John s wort are prepared from plant components (i.e., flowers, buds, and stalk) whose content of the wide array of structurally diverse bioactive constituents may differ (Table 1 and Fig. 2). Many commercial tablet and capsule formulations of St. John s wort are standardized using the ultraviolet absorbance of the naphtho-dianthrones, hypericin, and pseudohypericin, to contain 0.3% hypericin content. Thus, a 300 mg dose of St. John s wort contains approximately 900 pg hypericin per dose. Despite the standardization of dosage forms... 

Figure 3 Structures of (A) hypericin (B) pseudohypericin (C) hyperforin (D) flavo-noids (R=H quercetin R=a-L-rhamnosyl quercitrine R=P-D-glucosyl isoquerci-trine R=P-D-galactosyl hyperoside R=P-D-rutinosyl rutin R=P-o-glucuronide miquelianin) and (E) procyandin B2.

Neither hypericin, pseudohypericin, their glucuronic acid conjugates, nor their sulfate conjugates were detected in the urine (42). The chemical structure and molecular size (>500 Da) of hypericin and pseudohypericin suggest metabolism via hepatic glucuronidization followed by biliary excretion (42). 

Fig. 2. The structure of hypericin and its formation by photooxidation from protohypericin. In pseudohypericin, -CHOHCH3 is substituted for the CHj groups. In cyclopseudohypericin ring closure has occurred. In fagopyrin the CH3 groups are substituted by -CH3CjH8(CH3)ON.

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