Stability, hyperforin

As with drugs and purified biomarkers, thermal- and photostability of botanical products are the factors that must be considered. Commercial dried extract and capsules of SJW were evaluated under harmonized test conditions (25). Photostability testing showed all the constituents to be photosensitive in the tested conditions. However, different opacity agents and pigments influenced the stability of the constituents. Amber containers had little effect on the photostability of the investigated constituents. Long-term thermal stability testing showed a shelf life of less than four months for hyperforins and hypericins, even when ascorbic and citric acids were added to the formulation. 

Sample stability was also assessed. No stability issue was found when spiked brain homogenates were stored at room temperature (4 h), or in the processed samples over 48 h. The stability of hyperforin was also tested over three freeze-thaw cycles, which again did not reveal any significant degradation of the drug. 

In the recent years, a number of analogues more polar than hyperforin have been characterized in II. perforatum [50-52]. Due to the limited stability of hyperforin(s), the question rises however, whether those compounds are genuine metabolites or artifacts produced during the isolation and purification procedures. Figure (7) illustrates some of the oxidative degradation products of hyperforin which have been isolated from St. John s Wort. 

Cmde dried or fresh herb, fresh or dried flowers in olive oil, extracts, tinctures, synthetic hypericin, and so on. Hypericum oil, prepared by maceration of fresh flowers in sunlight for several weeks (usually in olive oil) acquires a red hue usually ascribed to hypericin or lipophilic substituted compounds with a hypericin-like color and fluorescence. Hyperforin is found in freshly macerated oil but is unstable, breaking down within 30-90 days stability can be increased to 6 months in storage by excluding air and using alternate preparation methods. ... 

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