Two new antioxidant active polyketides from Penicillium citrinum, an endolichenic fungus isolated from Parmotrema species in Sri Lanka

Abstract

Bioassay guided fractionation of the ethyl acetate
extract of a laboratory culture of Penicillium citrinum, an
endolichenic fungal strain isolated from a Parmotrema
species in Sri Lanka, led to the isolation of two new fungal
polyketides (1 and 2). The structures of these compounds
were determined on the basis of their 1D NMR, 2D NMR and
FABMS spectroscopic data. The two compounds (1 and 2)
showed radical scavenging activity with IC50 values of 159.7
± 22.3 μg/mL and 68.6 ± 4.3 µg/mL, respectively in DPPH
antioxidant assay. The antioxidant activity of compound 2 was
comparable to the standard antioxidant compound butylated
hydroxytoluene (BHT).