Alkaloid, noun: An ingredient in coffee: Compound containing nitrogen that is found in many plants. This includes caffeine at a ratio of 0.8 to 2.5%. In addition, coffee also includes low amounts of trigonelline, theobromine and theophylline. Roasting breaks down 75% of trigonelline, forming the vitamin niacin (nicotinic acid). One cup of coffee covers approximately one tenth of an adult’s daily requirement of niacin.