Antifungal compounds in Geraldton waxflower tissues

L. A. Terry, D. C. Joyce and B. P. S. Khambay

Abstract

Geraldton waxflower is the most economically important native Australian cut flower export. Infection of waxflower by Botrytis cinerea can lead to unacceptable levels of flower abscission after harvest. An investigation was conducted into the nature and identities of constitutive antifungal compounds in flowers and leaves. Antifungal activity against B. cinerea (pathogen) and Cladosporium cladosporioides (bioassay organism) was observed in leaf and flower extracts. Leaf tissue contained less antifungal activity than flower tissue. Four antifungal compounds were common to the three different waxflower cultivars studied. Two antifungal compounds were identified as the sesquiterpene, globulol, and the monoterpene, grandinol. At least two unidentified phenolic compounds also demonstrated strong antifungal activity. Notwithstanding general similarities in antifungal profiles, it was evident from TLC bioassays that variations exist in some antifungal compounds between different waxflower cultivars.

Keywords: Botrytis cinerea; thin layer chromatography bioassay.

Australasian Plant Pathology 32(3) 411 - 420 (2003) doi:10.1071/AP03042