THE EFFECTS OF AQUEOUS EXTRACTS OF Spirulina platensis ON THE GUINEA PIG TRACHEAL AND ILEAL SMOOTH MUSCLES

  Spirulina is a well-known dietary supplement that has been shown to have antiviral properties, anticancer properties and antioxidant effect. However, its use as a treatment for asthma is still controversial. There were reports which state that Spirulina can cause constipation and diarrhea too. To date, no study has been done on the effects of Spirulina extracts on the airway smooth muscles and gastrointestinal tract. The objective of this study was to investigate the effect of Spirulina aqueous extracts on the isolated guinea pig tracheal and ileal smooth muscles. 

              The algae powder was soaked in water. The aqueous extract was dried in vacuo using a rotary evaporator. The dried extracts was redissolved in water and stored at – 20^oC before use for the testing. Male guinea pigs were killed by cervical dislocation. The trachea and the ileum will be removed and transferred to a dish containing Kreb’s solution. The organs were mounted in an organ bath perfused with Kreb’s solution. Various concentrations of algae extracts were added to the Kreb’s solution to determine the effect of the extract on the contractility of smooth muscle. The contractions or relaxations of the muscle induced by the extracts and drugs were recorded.   

 

  The results revealed that Spirulina aqueous extract had neither significant contractile nor relaxant effect on the guinea pig tracheal smooth muscles. However, it produced a sustained dose-dependent contractile effect on the guinea pig ileum. The contractions were not affected by histamine (H₁) receptor antagonist, mepyramine and muscarinic antagonist, atropine. This suggests that the contraction observed in the presence of Spirulina aqueous extract is not due to the activation of histaminergic or muscarinic receptors.

 

  In conclusion, Spirulina aqueous extract causes no effect on guinea pig tracheal smooth muscles. However, it contracts the guinea pig ileum. The contraction caused by the Spirulina extracts is not due to the activation of muscarinic or histaminergic pathways. Thus this suggests that there are other possible mechanisms of action by which Spirulina aqueous extracts caused the contractile effect. The action of Spirulina on bronchioles needs to be investigated and long term effect of consumption of Spirulina on the airway reactivity should be studied.