Abstract

Syrian sage, Salvia syriaca L. (family Labiatae), is a common perennial weed in wheat fields in Jordan. The weed has a pronounced allelopathic activity on many agronomic crops. As part of our research on identifying growth inhibitors in plants, we tested the growth inhibitory effects of the aqueous weed extract on different plant species from different botanical families. Then we evaluated certain isolated compounds from the weed for their growth inhibitory activity on wheat seedlings. Oleanolic and ursolic acids showed remarkable growth inhibition of wheat seedlings as they reduced the lengths of shoots and roots of wheat seedlings when tested at 0.2 mg/1 (200 ppm). The compounds: 3 α hydroxy-11α-methoxy-17, 22-seco-17(28), 12-ursadien-22-oic acid (a), 1 β, 3 β dihydroxy-11 α methoxy-17, 22-seco-17(28), 12-ursadien-22-oic acid (b), and 1β, 3b-11α-trihydroxy-17, 22-seco-17(28) and 12-ursadien-22-oic (c) did not show growth inhibitory activity on the test plant.