Potential of black pepper as a functional food for treatment of airways disorders

The potential of black pepper (Piper nigrum) to cause bronchodilation was examined using in vivo and in vitro assays. HPLC fingerprint analysis of the crude extract of Piper nigrum (Pn.Cr) and its fractions showed piperine, piperidine, eugenol and catechin as plant constituents. In anaesthetized rats, Pn.Cr and piperine relieved carbachol (CCh)-induced bronchospasm. In isolated guinea-pig trachea, Pn.Cr and piperine inhibited CCh and K⁺ (80 mM)-induced contractions, potentiated isoprenaline concentration-response curves (CRCs) and suppressed Ca²⁺ CRCs. In guinea-pig atria, Pn.Cr and piperine showed stimulatory and inhibitory effects on rate and force of contraction. Its fractions showed similar activities with varied potency in the in vivo and in vitro assays. These results suggest that black pepper and piperine cause bronchodilation through dual inhibition of phosphodiesterase enzyme and Ca²⁺ influx, which substantiate its potential as a functional food ingredient for airway disorders.