Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2003
Publication Date: 11/17/2003
Citation: SALAH, M., BEDIR, E., TOYANG, N., KHAN, I., HARRIES, M.D., WEDGE, D.E. 2003.ANTIFUNGAL CLERODANE DITERPENES FROM MACARANGA MONANDRA (L) MUELL. ET ARG. (EUPHORBIACEAE). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY. 51:7607-7610. Interpretive Summary: Chemical extracts of equatorial rain forest tree, Macaranga monandra, of Cameroon showed antifungal activity to several Colletotrichum spp. using a simple bioautographic screening technique. Two clerodane-type diterpenes were separated, identified, and shown to possess antifungal activity to Phomposis viticola and Botrytis cinerea in a 96-well plate assay. However, because of their low antifungal activity we believe these compounds do not play a direct role in defense against fungal pathogenesis.
Technical Abstract: Hexane and EtOAc phases of MeOH extract of Macaranga monandra showed fungal growth inhibition of Colletotrichum acutatum, C. fragariae and C. gloeosporioides, Fusarium oxysporum, Botrytis cinerea, Phomopsis obscurans and P. viticola. Bioassay-guided fractionation led to the isolation of two active clerodane-type diterpenes that were elucidated by spectral methods (1D-, 2D NMR and MS) as kolavenic acid and 2-oxo-kolavenic acid. A 96-well microbioassay revealed that kolavenic acid and 2-oxo-kolavenic acid produced moderate growth inhibition in Phomopsis viticola and Botrytis cinerea.