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the commercial name for the glandules on the glumes of the fruit system (cones) and perianth of female hop blossoms (Humulus lupulus); also, the secretion from these glandules.
Solidified lupulin is a brownish yellow, sticky, coarse-grained powder containing essential oil, bitters, the alkaloid humulene, humulotannic acid, valerianic acid, gum, resin, wax, and a yellow pigment. Lupulin is used in brewing to give beer a pleasant, slightly bitter flavor, but it can also be toxic. A dose of 1-2 g may be mildly poisonous.