Apigenin
Apigenin is a flavonoid found in passion flower. It has shown antihistaminic effects, but is mainly used in sunscreens for protection from ultraviolet light. Apigenin has been used in dyeing wool, giving it an intense yellow color that will not wash away with soap.
References
Leung, Albert Y. 1980. Encyclopedia of Common Natural Ingredient used in Food, Drugs and Cosmetics. John Wiley and Sons, N Y. 409 pp.
Weiner, Michael and A. Janet Weiner. 1980. Weiner's Herbal The Guide to Herb Medicine. Stein and Day, New York. 224 pp.
Windholz, Martha, Susan Budavani, et. al. 1976. The Merck Index. Merck and Co., Inc. New Jersey.