Abstract
In this study, we employed a previously developed in vivo assay system to determine whether the flowers and leaves of Syringa vulgaris (S. vulgaris; commonly known as "lilac") can prevent blood stasis syndrome, known as oketsu in Japanese. This syndrome is considered an important pathology in traditional Chinese and Japanese medicine, and is related to diseases such as peripheral vascular disorders, blood vessel inflammation, and platelet aggregation, whose severities are augmented owing to lipid peroxidation, free radicals, and oxidative stress. The assay system employed in this study monitored the blood flow decrease in the tail vein of mice subjected to sensitization with hen egg white lysozyme. Through bioassay-guided fractionation of different S. vulgaris extracts, five polyphenols were isolated and identified. Among them, quercetine 3-glucoside, quercetin 3-rutinoside, and acteoside were identified as active compounds, as they significantly mitigated blood flow reduction. These findings indicate that the polyphenols obtained from S. vulgaris could be useful for preventing oketsu and improve the quality of life of individuals with disorders and diseases such as gynecopathy, cold sensitivity, poor circulation, allergy, and lifestyle-related diseases.