Background: The involvement of debilitating side effects of allopathic antiasthmatic
drugs provides a strong impetus for the development of new herbal therapeutics.
Myrica nagi Thunb. (Syn. Kaiphal) of Myricaceae family is a known drug of the Ayurveda
system used for the treatment of several diseases including asthma.
Methods: The present study deals with the preparation and phytochemical screening of polar,
non-polar and methanolic extracts of Myrica nagi bark followed by the evaluation of their
antiasthmatic activity using four different animal experimental models: acetylcholine induced
bronchospasm in conscious guinea pigs, acetylcholine induced contraction on isolated guinea
pig tracheal chain preparation, compound 48/80 induced mast cell degranulation using rat,
and trypsin and egg albumin induced bronchospasm in conscious rat.
Results: Polar extract of M. nagi bark (200 mg/kg, p.o.) exerted strong antiasthmatic effects
near to Ketotifen (1 mg/kg, p.o) as standard drug. Polar extract of M. nagi bark (200 µg/ml)
significantly inhibited Ach induced contraction of isolated guinea pig tracheal chain preparation.
Pre-incubation of rat peritoneal mast cells with test drugs (methanolic, non polar and polar
extracts) showed dose dependent significant reduction of % mast cell degranulation. Polar
extract (200mg/kg) & Methanolic extract (200mg/kg) of M. nagi bark treated animals showed
significantly lesser serum bicarbonate level, higher tidal volume, lower level of eosinophils
Conclusion: The results of present investigation suggest that the polar extracts of Myrica
nagi bark have better antiasthmatic activity than the non polar and methanolic extract.