Vitamin K1 (phylloquinone) content of green vegetables: effects of plant maturation and geographical growth location

The vitamin K 1 (phylloquinone) content of five vegetables (cabbage, Swiss chard, leaf lettuce, spinach, and kale) was determined by reversed-phase high-performance liquid chromatography. The plants were grown from seeed at two different locations (Boston, MA; Montreal, Canada) and analyzed with respect to maturation, soil conditions, and climatological effects. The green vegetables were found to be excellent sources of vitamin K 1 (5-16 μg/g). For most vegetables except cabbage, vitamin K 1 contents increased during maturation