The free radical scavenging effect of crude methanolic
extract of G. velutinus was determined using the DPPH
method. The extracts of leaves and bark show EC50 values
of 155 lg/mL and 204 lg/mL respectively, where the EC50 values
of trolox and ascorbic acid are 5 lg/mL and 4 lg/mL. The
results show that at 10 lg/mL concentration of trolox and
ascorbic acid shows maximum inhibition of DPPH i.e., 91%
and 96% respectively, while at the same concentration bark
and leaf extracts show very low inhibition of DPPH. Methanolic
leaf extract of G. umbrosus was reported to have promising
antioxidant activity with EC50 value of 263 lg/mL