Piperine

Piperine is the alkaloid responsible for the pungency of black pepper and long pepper, along with chavicine (an isomer of piperine). It has also been used in some forms of traditional medicine and as an insecticide. Piperine forms monoclinic needles, is slightly soluble in water and more so in alcohol, ether or chloroform: the solution in alcohol has a pepper-like taste. It yields salts only with strong acids. The platinichloride B₄•H₂PtCl₆ forms orange-red needles. ("B" denotes one mole of the alkaloid base in this and the following formulae.) Iodine in potassium iodide added to an alcoholic solution of the base in presence of a little hydrochloric acid gives a characteristic periodide, B₂•HI•I₂, crystallising in steel-blue needles, mp. 145°C. Anderson first hydrolysed piperine by alkalis into a base and an acid, which were later named piperidine and piperic acid respectively. The alkaloid was synthesised by the action of piperoyl chloride on piperidine.