BIOACTIVE OXYLIPINS FROM THE ENDOPHYTE KHUSKIA ORYZAE ISOLATED FROM THE MEDICINAL PLANT BIDENS ALBA
Randa Abdou* and Kamel Shaker
ABSTRACT
An endophytic fungus was isolated from the medicinal plant Bidens
alba and was identified as Khuskia oryzae on the basis of ITS sequence
comparison. The ethyl acetate extract of the fungal isolate obtained
exhibits antimicrobial activity in agar diffusion assays as well as
cytotoxic and antiproliferative effects. Activity-guided
chromatographic fractionation resulted in the isolation of the active
metabolites which were identified by different spectroscopic techniques as the bioactive
oxylipin called 8-oxo-(9E, 11E)-octadecadienoic acid and the oxygenated bioactive fatty acid
9-oxo-(10E, 12E)-octadecadienoic acid. A cytotoxic assay was performed for the compounds
and revealed the first to be of cytotoxic activity against HeLa cell lines with a CC50 value of
42.6 μg mL-1 and cytostatic activity against HUVEC and K-562 cancer cell lines with GI50
values of 40.7 μg mL-1 and 41.5 μg mL-1 respectively. The cytotoxic assay performed on 8-oxo-(9E, 11E) octadecadienoic acid showed cytotoxicity
against HeLa cell lines with a CC50 value of 33.3 μg mL-1 and cytostatic activity against
HUVEC and K-562 cell lines with a GI50 value of 30.8 μg mL-1 and 28.8 μg mL-1
respectively. In the antimicrobial assay performed against B. subtilis and A. terreus weak antibacterial and
antifungal activities were observed for 9-oxo-(10E, 12E)-octadecadienoic acid (inhibition zone 16 mm and 12 mm at a conc. of 250 μg mL-1 respectively), while moderate antibacterial
and antifungal activities were detected for 8-oxo-(9E, 11E)-octadecadienoic acid (inhibition
zone 20 mm and 16 mm at a conc of 250 μg mL-1respectively).
Keywords: oxylipin, endophyte, Khuskia oryzae, Bidens alba.
[Full Text Article]