Octanoyl-6-O-ascorbic acid: an efficient antioxidant with potent solubilising properties The case of active constituents from Saint John’s wort.

This paper describes the use of octanoyl-6-O-ascorbic acid to protect all the characteristic constituents of Saint John’s wort (Hypericum perforatum L.) from oxidation processes. Given the intrinsic ability of octanoyl-6-O-ascorbic acid to form micelles, aqueous solubility of the constituents has also been increased. Thermal and photostability of SJW commercial dried extract in the presence of octanoyl-6-O-ascorbic acid were evaluated according to ICH test conditions. ASC8 increased the stability of the constituents of the extract, in particular naphtodianthrones; and a very high increment of shelf life of phloroglucinols was also evidenced in the accelerated test. In addition, octanoyl-6-O-ascorbic acid improved the solubility of total phloroglucinols. Octanoyl-6-O-ascorbic acid could represent an appropriate and auxiliary excipient to improve the technological and biopharmaceutical characteristics of SJW extract.