Plant growth inhibitors: Patchoulane‐type sesquiterpenes from Cyperus rotundus L.

Abstract

Two sesquiterpene ketones, cyperotundone and α -cyperone, were isolated from dried tubers of purple nutsedge ( Cyperus rotundus L.) as major constituents: ≈ 0.26% and 0.1% of dried tuber, respectively. These allelochemicals affect plant growth, but we consider that these terpenoids undergo modification when they are released into the rhizosphere from the donor plant. For the structure-activity relationship study, cyperotundone was oxidized with selenium dioxide in acetic acid to 4-patchoulene-2,3-dione and 4-patchoulene-2,3,6-trione. Subsequent hydrogenation of 4-patchoulene-2,3-dione and 4-patchoulene-2,3,6-trione gave hydroxylated derivatives, cyperotundon-2-ol and 3-hydroxy-4-patchoulene-2,6-dione, respectively. 4-Patchoulene-2,3-dione inhibited the hypocotyl growth of lettuce seedlings but promoted radicle elongation at 0.1 − 2 mg L − 1 concentration without chlorosis. Moreover, this radicle elongation recovered with the addition of galactose and was not antagonized by gibberellin A 3 . The effect of 4-patchoulene-2,3,6-trione showed a similar chlorosis, caused by 3,6,9-sugetriol triketone, against lettuce seedlings. These ketones did not show the radicle elongation.

Regulation of Cell Division and Growth in Roots of Lactuca sativa L. Seedlings by the Ent-Kaurene Diterpenoid Rabdosin B

“…Numerous mono-and sesquiterpenes have been identified as allelochemicals and their modes of action have been investigated (Muller 1966;Rice 1984;Duke and Oliva 2002;Macías et al 2004Macías et al , 2007Morimoto and Komai 2005;Nishida et al 2005;Cantrell et al 2007). However, there are fewer reports concerning the phytotoxic properties of diterpenoids (Macías et al 1999(Macías et al , 2000.…”

Allelochemicals: sources, toxicity and microbial transformation in soil —a review

“…Living organisms encode enzymes that detoxify the ROS (Testa, 1995). So, the biological activities of new compounds would differ from the original ones (Morimoto and Komai, 2005). First allelochemical naphthoquinone juglone, isolated from black walnut tree was in fact an artefact obtained during the isolation procedure from the plant (Williamson and Weidenhamer, 1990).…”

“…Precursor of juglone released from the plant as a glucoside, is converted to juglone and degraded into other derivatives by microorganisms. Two allelochemicals cyperotundone and -cyperone and their derivatives isolated from tubers of purple nutsedge were modified after released into the rhizosphere, and their allelopathic effects were also rendered on lettuce seed germination and seedlings (Morimoto and Komai, 2005).…”

New Patchoulane-Type Sesquiterpenes from the Rhizomes of Cyperus rotundus

“…Its HR-DART-MS gave a pseudo-molecular ion peak at m/z H-NMR spectrum of 1 revealed some signals common to patchoulane-type sesquiterpenes, namely the two geminal methyl groups H-12 and H-13 (δ 0.85 and 1.03, respectively; each 3H, s), the methyl group H-15 at δ 0.94, appearing as a doublet (3H, J = 6.5 Hz) and coupling with the methine proton H-10 (δ 2.12, 1H, dq, J = 10.5 and 6.5 Hz), and the vinyl methyl group H-14 at δ 1.67, appearing as a broad singlet. Comparison of the above with data in the literature 4,6,12 suggested that 1 was a cyperene-related compound with patchoulane skeletone bearing two acetoxyl groups. These assignments were supported by 2D NMR techniques.…”