Residues of St. John’s Wort (Hypericum perforatum) Tea Infusions/Water Extracts as a Valuable Source of Tocotrienols: An Extraction Study

Hypericum perforatum L., commonly known as St. John’s wort, is a widely distributed herbaceous plant utilized in traditional and phytomedicinal applications, particularly for its hydrophilic bioactive compounds. It is often used for treating early depressive states. In this study, we focused on reporting the tocotrienols—lipophilic phytochemicals with health-promoting properties—in St. John’s wort. H. perforatum flowerheads predominantly contained tocotrienols compared with tocopherols (54 and 30 mg/100 g dry weight, respectively). The major tocotrienols (T3) were δ-T3 and α-T3 (34.0 and 17.6 mg/100 g dry weight, respectively). Tocopherols and tocotrienols are lipophilic phytochemicals that cannot be present in St. John’s wort water extracts (tea infusions), but they can be recovered from the remaining residues of H. perforatum tea infusions by using hydroethanolic solutions. A 50.0% (v/v) hydroethanolic solution was not effective in the recovery of tocochromanols. The greatest increase in the extractability of tocochromanols was observed for 70.0–80.0% (v/v) hydroethanolic extracts, while increasing the ethanol concentration from 90.0% to 96.2% (v/v) only slightly improved extractability (not statistically significant). For each ethanol concentration, the recovery was proportionally higher for tocotrienols than for tocopherols. Residues of H. perforatum tea infusions can be proposed as valuable by-products rich in tocotrienols.