Curcumin (diferuloylmethane), a natural product from the rhizomes of Curcuma longa is a yellow colored polyphenolic

rhizomes of Curcuma longa is a yellow colored polyphenolic phytochemical which has been in use for a long time for the treatment of swelling, twisting and wounds. The Indian system of medicine uses curcumin, present in its raw form in the plant extract, as a wound healer and inhibitor of swelling. As a pure compound also, it has been found to possess antitumor, anti-cancer and anti-inflammatory activities. Several studies have clearly indicated that curcumin possesses a variety of pharmacological effects such as in wound-healing, anti-oxidant and anti-inflammatory activities. Certain recent studies indicated that curcumin may exert its anti-inflammatory properties by: a) suppressing the activation of NF-kappaB through inhibition of IKK activity, b) significantly inhibiting the LPS induced proinflammatory cytokines IL-1beta and IL-8 and c) inhibiting iNOS production and by scavenging NO radicals. There is some evidence that curcumin has anti-spasmodic effect on smooth muscle of dogs’ intestine in-vivo and vas-defrens of guinea pig in-vitro. Based on these inflammatory and anti-spasmodic properties of curcumin, we hypothesized that it could have anti-asthmatic activity as well because asthma is a chronic airway inflammatory disorder. Asthma pathogenesis involves airway inflammation coupled with airway hyperresponsiveness (AHR) to a variety of physical and pharmacological stimuli. The incidence of asthma is on the rise globally and is reaching epidemic proportions. The already existing remedies for asthma are known to possess detrimental side effects on prolonged use. Therefore, there is a need to explore for new anti-asthmatic agents, preferably a plant-based drug that has negligible side effects. For our study, we selected a guinea pig model because of its marked airway reactivity and a good similarity to the airways of asthmatic human subjects. To test the effect of curcumin, we sensitized the animals with ovalbumin (OVA) to develop the characteristic features of asthma: antigen induced airway constriction and airway hyperreactivity to histamine. We report here for the first time that curcumin inhibits allergen induced airway constriction and airway hyperreactivity to histamine in guinea pigs.