Hypericin and Pseudohypericin

The aromatic polycyclic diones hypericin and pseudohypericin, which are present in plants of the family Hypericum (St. John s wort), have been accredited with anti-HIV activity for more than a decade. They possess the capacity to inactivate HIV virions directly as well as to interfere with their assembly or processing. Hypericin has received continued interest as a potential therapeutic agent and was more recently found to interact with preintegration complexes (PICs) and thus affect the proviral DNA integration process (De Clercq, 2000). 

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Extracts of hypericum may vary considerably in terms of the quantity and ratio of their constituents based on the extraction process used. Maximum extraction of hypericin and pseudohypericin is obtained with an 80% methanol solvent at 80°C (Wagner and Bladt 1994). Hyperforin is a lipophilic constituent of hypericum that is present in the oil extract (Chatterjee et al. 1998a). It is not very stable, but its presence is sustained by hot maceration of the flowers and storage in the absence of air (Maisenbacher and Kovar 1992). 

The pharmacokinetics of hypericin and pseudohypericin piasma have been studied as weii (Brockmoiier et ai. 1997). Human subjects receiving piacebo, or 900, 1800, or 3600 mg of a standardized hypericum extract (LI 160), which contained 0, 2.81, 5.62, and 11.25 mg of totai hypericin and pseudohypericin, achieved maximum total plasma concentrations at 4 hours (0.028, 0.061, and 0.159 mg/L, respectively). The half-lives of absorption, distribution, and elimination were 0.6, 6.0, and 43.1 hours, respectively, using 750 pg of hypericin, and are slightly different for 1578 pg of pseudohypericin (1.3, 1.4, and 24.8 hours, respectively) (Kerb et ai. 1996). The systemic availability of the hypericum extract LI 160 is between 14 and 21%. Comparable results are found in another study using LI 160 (Staffeldt et ai. 1994). Long-term dosing of 3 x 300 mg per day showed that steady-state levels of hypericin are reached after 4 days. 

Kerb R, Brockmoiier J, Staffeldt B, Ploch M, Roots I. (1996). Single-dose and steady-state pharmacokinetics of hypericin and pseudohypericin. Antimicrob Agents Chemother. 40(9) 2087-93. Kim HL, Streltzer J, Goebert D. (1999). St. John s wort for depression a meta-analysis of well-defined clinical trials. J Nerv Ment Dis. 187(9) 532-38. 

Staffeldt B, Kerb R, Brockmoller J, Ploch M, Roots I. (1994). Pharmacokinetics of hypericin and pseudohypericin after oral intake of the hypericum perforatum extract LI 160 in healthy volunteers. J Geriatr Psychiatry Neurol. 7(suppl 1) S47-53. 

Takahashi I, Nakanishi S, Kobayashi E, Nakano H, Suzuki K, Tamaoki T. (1989). Hypericin and pseudohypericin specifically inhibit protein kinase C possible relation to their antiretroviral activity. Biochem Biophys Res Common. 165(3) 1207-12. 

This herbal product has the most data available to support its usefulness as an antidepressant. Nevertheless, only minimal information is available about its pharmacology and its relative risk-benefit ratio. At least seven different biologically active chemicals have been isolated from crude extracts of hypericum. Several are ubiquitous in the plant kingdom. The exceptions are hypericin and pseudohypericin, which have been assumed to be responsible for any antidepressant activity of this product. Nevertheless, there is the potential for one or more of these seven compounds and their metabolites to mediate desired or undesired effects, particularly when used in combination with other medications (i.e., herb-drug interactions). 

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... 

Draves AH, Walker SE. Analysis of the hypericin and pseudohypericin content of commercially available St John s Wort preparations. Can J Clin Pharmacol 2003 10(3) 114-118. 

The pharmacological activity of SJW extracts has recently been reviewed (55-58). Recent reports have shown that the antidepressant activity of Hypericum extracts can be attributed to the phloroglucinol derivative hyperforin (59-62), to the naphthodianthrones hypericin and pseudohypericin (18,63-65), and to several flavonoids (66-69). The role and the mechanisms of action of these different compounds are still a matter of debate. But, taking these previous findings together, it is likely that several constituents are responsible for the clinically observed antidepressant efficacy of SJW. 

Single- and multiple-dose pharmacokinetic studies with extracts of SJW were performed in rats and humans, which focused on the determination of plasma levels of the naphthodianthrones hypericin and pseudohypericin and the phloroglucinol derivative hyperforin. Results from pharmacokinetic... 

A placebo-controlled, randomized clinical trial with monitoring of hypericin and pseudohypericin plasma concentrations was performed to evaluate the increase in dermal photosensitivity in humans after application of high doses of SJW extract (Table 2) (73). The study was divided into a single-dose and a multiple-dose part. In the single dose crossover study, each of the 13 volunteers received either placebo or 900, 1800, or 3600 mg of the SJW extract LI 160. Maximum total hypericin plasma concentrations were observed about four hours after dosage and were 0, 28, 61, and 159ng/mL, respectively. Pharmacokinetic parameters had a dose relationship that appeared to follow linear kinetics (73). 

In another study, the concentrations of hypericin and pseudohypericin in serum and skin blister fluid after oral intake (single and steady state) of... 

Animal studies Early pharmacokinetic studies in mice report that maximum plasma concentrations of hypericin and pseudohypericin were reached at six hours and were maintained for at least eight hours. The aqueous-ethanolic SJW extract used in this study contained 1.0 mg of hypericin (77). 

Butterweck V, Petereit F, Winterhoff H, Nahrstedt A. Solubilized hypericin and pseudohypericin from Hypericum perforatum exert antidepressant activity in the forced swimming test. Planta Med 1998 64 291-294. 

Brockmoeller J, Reum T, Bauer S, Kerb R, Huebner WD, Roots I. Hypericin and pseudohypericin and effects on sensitivity in humans. Pharmacopsychiatry 1997 30 94-101. 

Kerb R, Brockmoeller J, Staffeldt B, Ploch M, Roots I. Single-dose and steady state pharmacokinetics of hypericin and pseudohypericin. Antimicrob Agents Chemother 1996 40 2087-2093. 

Stock S, Hoelzl J. Pharmacokinetic tests of (14C)-labeled hypericin and pseudohypericin from Hypericum perforatum and serum kinetics of hypericin in man. Planta Med 1991 57 A61. 

Women use herbal and dietary supplements at higher rates than men do. This rise in use of alternative therapies places women at increased risk of significant drug interactions, specifically drug-herb and drug-nutrient interactions (83 9). For instance, St. John s wort, a popular antidepressant, contains at least seven groups of chemical compounds. These include naphthodianthrons (hypericin and pseudohypericin), flavonoids (quercetin, hyperoside, and rutin). 

Hypericum perforatum (devil s scourge, goat weed, rosin rose, St. John s wort, Tipton weed, witch s herb) contains the naphthodianthrones hypericin and pseudohypericin, flavonoids, such as hyperoside, isoquercitin, and rutin, and phloroglucinols, such as adhyperforin and hyperforin. It is effective in mUd to moderate depression (1). 

It was once thought that hypericin was the main active ingredient in St. John s wort. In 1994, it was reported that hypericin inhibited MAO-A (11). Further studies have shown that hypericin and pseudohypericin do not inhibit MAO-A, and hypericum extracts only inhibit MAO at extremely high concentrations (5). Furthermore, hypericin did not display a significant (>25%)... 

Two pharmacokinetic studies have examined the pharmacokinetics of hypericin and pseudohypericin (41,42). Standardized hypericum extract LI 160 (Jarsin 300 , Lichtwer Pharma GmbH, Berlin) was used in both trials. In Part I of the studies, subjects in both trials were administered a single dose of either 300, 900, or 1800 mg of the extract (one, three, or six coated tablets) at 10- to 14-day intervals. Each dose contained 250, 750, or 1500 p.g of hypericin and 526, 1578, or 3156 p,g of pseudohypericin, respectively. The doses were administered on an empty stomach in the morning after a 12-hour fast. Subjects fasted for an additional 2 hours after administration. Multiple plasma levels of hypericin and pseudohypericin were measured for up to 120 hours after administration. In addition, urine samples were collected in the study performed by Kerb and colleagues. After a 4-week washout from Part I, subjects were given one coated tablet containing 300 mg of hypericum extract three times a day (8 am, 1 pm, and 6 pm) before meals for 14 days. Blood samples were obtained over the 2-week dosing period. 

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). 

Lavie G, Valentine F, Levin B, et al. Studies of the mechanisms of action of the antiretroviral agents hypericin and pseudohypericin. Proc Natl Acad Sci USA 1989 86 5963-5967. 

Emit of detection was 4 ng mL and the limit of quantitation was 10 ng mL Bauer et al. described HPLC combined with UV detection for the determination of hyperforin and HPLC combined with fluori metric detection for the determination of hypericin and psudohypericin in human plasma. They used liquid-liquid extraction. The limit of quantitation was 10 ng mL for hyperforin and 0.25 ng mL for both hypericin and pseudohypericin. 

Bauer S, Stormer E, Graubaum HJ, Roots 1. Determination of hyperforin, hypericin and pseudohypericin in human plasma using high-performance liquid chromatography analysis with fluorescence and ultraviolet detection. J Chromatogr B 2001 765 29-35. 

L., family Hypericaceae. Hypericum contains flavonoids, xanthones, naphthodianthrones such as hypericin and pseudohypericin and phloroglucinols, e.g. hyperforin. Hypericin has anti-HIV activity and is responsible for the photosensitivity reaction which has been documented for St. John s Wort in cattle and... 

A difference is observed between the 7lag of hypericin compared to pseudohypericin. These differences may be a function of the dosage form given. Pseudohypericin may be released from the dosage form more quickly than hypericin. Also, hypericin and pseudohypericin may be absorbed in different locations in the gastrointestinal tract. Another explanation may be that hypericin may undergo first-pass hepatic metabolism (Staffeldt et ah, 1994). 

Hypericin and pseudohypericin content of plasma and urine has been measured using HPLC with a spectrofluorometric detector (Kerb et al., 1996 Liebes et al., 1991). HPLC with a UV photometric detector has also been used to analyze plasma (Staffeldt et al., 1994). 

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