Evaluation of urease inhibitory and free radical scavenging activities of Microsorum pustulatum (G. Frost) copel leaves (Polypodiaceae)

Abstract

Microsorum pustulatum is an epiphytic fern. Young leaves and stems are edible, used in wound healing (ulcer), treatment of inflammation and skin infections. This study is reporting the effect of the leaves extracts and fractions of Microsorum pustulatum on the urease enzyme as well as their free radical scavenging activity. The leaves extracts were obtained by successive cold maceration in n-hexane, acetone and 70% aqueous ethanol. Phytochemical screening was done using standard methods. Urease inhibition assay was done using the modified Berthelot method with thiourea as reference standard urease inhibitor. The free radical scavenging activity was assayed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) with ascorbic acid as reference standard. The organic (AOP) and aqueous (AAP) fractions were obtained by chloroform-water partitioning of the most active acetone extract. The acetone extract (anti-urease=51.6%, DPPH radical scavenging= 49.9%) and its AOP fraction (anti-urease= 43.3%, DPPH radical scavenging= 70.31%) were observed to have good urease inhibition and free radical scavenging effect when compared with standard at the same 1mg/ml test concentration. The trend in median DPPH radical inhibition concentration: AOP (IC50 = 0.09 mg/ml) > AAP (IC50=0.64 mg/ml) was also observed. The phyto-constituent present in the screened leaf extract are saponins, tannins, phlobatannins, phenolic, flavonoids, terpenoids, steroids, carbohydrates. In conclusion the result validates the traditional use of Microsorum pustulatum leaves in treatment of disease such as ulcer, chronic inflammation etc. caused by pathogenic microorganism (Helicobacter pyroli, Proteus mirabilis etc.) that needs urease for survival and to curb inflammation in oxidative stress state. Also acetone extract of the plant can be used as additive to urea base fertilizer in the development of ecofriendly urease inhibitors and increase in crop production.