Stability of Danggwisu-san (Dangguixu-san) Water Extract, a Herbal Medicine, Under Various Storage Conditions

Objectives Danggwisu-san (Dangguixu-san) is a herbal prescription frequently used to treat pain or swelling caused by contusion. To determine the expiration period through scientific methodology, stability of Danggwisu-san (Dangguixu-san) water extract, a herbal medicine, was examined under various storage conditions and periods. Methods Danggwisu-san (Dangguixu-san) was stored either at room temperature ($23{\pm}2^{\circ}C$), under a refrigerating condition ($4^{\circ}C$) or under a freezing condition ($-18{\pm}2^{\circ}C$) for 0, 1, 2, 3 or 4 weeks and then freeze-dried. Total phenol and total flavonoid amounts were investigated; contents of amygdalin (Prunus persica), paeoniflorin (Paeonia lactiflora), and glycyrrhizin (Glycyrrhiza uralensis) - the marker compounds of Danggwisu-san (Dangguixu-san) - were also analyzed through high performance liquid chromatography (HPLC). Results No significant change in total phenol and total flavonoid amounts was observed under the indicated storage conditions. Moreover, the contents of marker compounds, i.e. amygdalin, paeoniflorin, and glycyrrhizin, did not alter significantly under the indicated conditions, as well. Conclusions Danggwisu-san (Dangguixu-san) was found to be stable up until 4 weeks under the indicated conditions. Further studies on efficacy and long-term stability are warranted to establish the expiration period of Danggwisu-san (Dangguixu-san).