Observations on the nature of vitamin P and the vitamin P potency of certain foodstuffs

Abstract

Hesperidin and hes-peretin, prepn. from orange meal, increased capillary resistance in man when given by mouth in aqueous suspension, but neither can be regarded as vit. P. Hesperidin was more than twice as active as the aglycone; the prepn. contained no significant quantities of chalcone. Certain water soluble extracts were much more active but the active principles are as yet unknown. The vit. P potency of many fruits and vegetables was detd. and did not parallel ascorbic acid content. Vit. P potency as assessed by capillary resistance is destroyed by boiling in air or by shaking with charcoal; a slow but gradual loss was observed in a prepn. of black currants stored at 20[degree] in the dark in absence of oxygen. Loss of vit. P activity from fruit prepn. may be expected under ordinary storage conditions. Rutin was also active.