THE SEARCH FOR GERMINATION STIMULANTS IN PLANT-DERIVED SMOKE EXTRACTS

Aqueous extracts of plant-derived smoke stimulates seed germination. To isolate the active compound(s), smoke extracts of Passerina vulgaris and Themeda triandra were subjected to bioassay-guided fractionation. Purification steps included liquid-liquid partitioning, semi-preparative HPLC, two TLC systems and analytical HPLC. Each purification step was examined using the lettuce seed germination bioassay. Biologically active fractions were selected for further purification. Active fractions from the last HPLC purification step were analysed by high-resolution GC-MS. Twelve compounds were identified, of which seven were present in both the P. vulgaris and T. triandra extracts. Four of the compounds that were commercially available were tested in the lettuce seed bioassay and were found to be inactive.