The seed oils from Acacia arabica varieties - Telia babul, Vediana and Cupressiformis were found to contain unique occurrence of unusual fatty acids, 9,10-epoxy-octadec-cis-12-enoic acid (coronaric acid, 9.0%, 7.0% and 7.5%), 7-(2-octacyclopropen-1-yl)heptanoic acid (malvalic acid, 2.5%, 2.1% and 2.2%) and 8-(2-octacyclopropen-1-yl)octanoic acid (sterculic acid, 2.1%, 1.1% and 1.8%), respectively along with the other normal fatty acids. These fatty acids were determined and characterized by UV, FTIR, H-1 NMR, MS, GLC-techniques and chemical degradations. (C) 2002 Elsevier Science B.V. All rights reserved.