Catnip (Nepeta cataria) and Indigestion: evidence and sources

Aim of the study The study was aimed to investigate the chemical composition and pharmacological basis for traditional use of essential oil of Nepeta cataria L. (Limiaceae) (Nc.Oil) in gastrointestinal and respiratory disorders. Materials and methods Chemical analysis was carried out through GC-EIMS, 13C NMR and Kovats Retention Indices while pharmacological study was carried out in isolated tissues preparations. Results Four major components; 1,8-cineol (21.00%), alpha-humulene (14.44%), alpha-pinene (10.43%) and geranyl acetate (8.21%) were identified among the 27 compounds in Nc.Oil. In isolated rabbit jejunum, Nc.Oil, papaverine and verapamil inhibited spontaneous and high K+(80 mM) precontractions, as well as shifted the Ca++ concentration-response curves (CRCs) to right, indicating calcium channel blocking activity. In isolated guinea-pig trachea, Nc.Oil and papaverine inhibited carbachol (1 microM) and K+ precontractions with similar potency, while verapamil was more potent against K+. Nc.Oil also potentiated isoprenaline inhibitory CRCs, similar to papaverine, indicating papaverine-like PDE inhibitor activity. In isolated guinea-pig atria, Nc.Oil caused cardiodepression at around 25-80 times higher concentrations, similar to papaverine. Conclusions These data indicate that Nepeta cataria possesses spasmolytic and myorelaxant activities mediated possibly through dual inhibition of calcium channels and PDE, which may explain its traditional use in colic, diarrhea, cough and asthma.

Nepeta cataria Linn (Family Labiatae), commonly known as catnip, is a herbaceous plant and is a native of southeast Europe, Orient, Southwest Asia and Western temperate Himalayas. Leaves and flowering tops, which contain tannin and volatile oil are aromatic, carminative, tonic, diaphoretic, refrigerant, emmenagogue, antiseptic, stimulant and useful in infantile colic and hysteria. Leaves are deltoid-oval with double layers of palisade, petiole about as long as blade, arc shaped in t.s., having vascular bundle flanked by 2 smaller bundles in two projection; stem hollow in the middle; leaves, petioles and stems contain glandular and uniseriate, multicellular non glandular hairs; TLC of alcoholic extract in Benzene: Chloroform (1:1) shows 8 spots and UV absorbance shows strong peak at 212 nm; extractive values and ash values were also determined.