Phytotoxic Activity of Salvia x jamensis J. Compton.

In a previous paper we described the platelet antiaggregating activity of the surface exudate of Salvia x jamensis J. Compton [1]. This exudate also showed a good antigerminative activity against Papaver rhoeas L. and Avena sativa L. [2]. Bioguided fractionation of the exudate with column chromatography on Sephadex LH-20 and silica gel yielded eight active components. These were identified as the known compounds 15, 16-epoxy-cleroda-3-en-7α, 10β-dihydroxy- 12,17; 19,18-diolide (1), isopimaric acid (2), 14-α-hydroxy-isopimaric acid (3), 3-β-hydroxyisopimaric acid (4), 7,8-β-dihydrosalviacoccin (5), hautriwaic acid (6), betulinic acid (7), cirsiliol (8). Various concentrations of these substances were used for dose-response studies. Seed germinability was assessed by determining the final cumulative percentage of germination at the end of tests; germination progress was followed by the calculation of other indices, i.e. the speed of germination, the speed of accumulated germination and the coefficient of the rate of germination [3]. The lethal concentrations needed to reduce germinability by 50% (LC Dipartimento di Scienze Farmaceutiche, Universidad de Salerno, Salerno, Italia. 50) and by 90% (LC90 [1] Bisio A, Romussi G, Russo E, De Tommasi N, Mascolo N, Alfieri A, Bonito MC, Cicala C. (2008) Platelet Antiaggregating Activity and Chemical Constituents of Salvia x jamensis J. Compton. Natural Products Communications 3, 881-884. ) were predicted by linear interpolation between the two adjacent values corresponding respectively to 50% and 90% response of the total germination of the seeds for each tested substance [4]. The compounds most active in inhibiting the germination of both the tested species were 4, 5, 6, and 7. They were not significantly different from each other, but significantly different from the other compounds and from control. [2] Bisio A, Russo E, Romussi G, Fraternale D, Ricci D, Giampieri L, Bucchini A., De Tommasi N, Cafaggi S.(2008) Preliminary results of herbicidal activity of Salvia spp. against common weeds. FITOMED 2008, III Congresso Intersocietà sulle Piante Medicinali, Salerno, 25-27 giugno 2008. [3] Chiapusio G,Sanchez A M, Reigosa M J, Gonzalez L, Pellissier F. 1997. Do germination indices adequately reflect allelochemical effects on the germination process?. Journal of Chemical Ecology. 23, 2445-2453 [4] Dayan FE, Romagni JG, Duke SO. 2000. Investigating the mode of action of natural phytotoxins. Journal of Chemical Ecology. 9, 2079-2094.