Phytochemical profile and in vitro anti-inflammatory activity of aqueous leaf extract of Sri Lankan variety of Psidium guajava L

Abstract

The leaves of Psidium guajava L. (Common name: Guava/Yellow Guava/ Lemon Guava) have proven medicinal values. The aims of this study were, to evaluate the phytochemical constituents and the anti-inflammatory properties of freeze-dried aqueous leaf extract Sri Lankan variety of P. guajava L. Phytochemical investigation was done with standard qualitative tests and revealed the presence of terpinoids, alkaloids, carbohydrates, flavonoids, tannins, phenols, glycosides, and proteins. The anti-inflammatory activity was determined by two in vitro models: inhibition of heat induced denaturation (which is an index of anti-inflammatory activity) of egg albumin and Bovine serum albumin. The percentage inhibition of denaturation of egg albumin (R2 = 0.612, p = 0.01) and Bovine serum albumin (R2 = 0.621, p = 0.01) were dose dependent. The maximum inhibition was observed at 125 µg/ml (IC50 = 15.625 µg/ml) for egg albumin and at 500 µg/ml (IC50 = 50 µg/ml) for Bovine serum albumin. The anti-inflammatory effect obtained in Bovine serum albumin denaturation test was comparable to reference drug, Diclofenac sodium and in egg albumin denaturation test it was higher approximately 30 fold higher than the reference drug. It is concluded that the aqueous leaf extract of the Sri Lankan variety of P. guajava L. possesses marked anti-inflammatory activity in vitro and this is a novel finding.