Synthesis and plant growth inhibitory activity of N-trans-cinnamoyltyramine: its possible inhibition mechanisms and biosynthesis pathway

Figures & data

Scheme 1. Synthesis of N-trans-cinnamoyltyramine (1) from trans-cinnamic acid (2) and tyramine (3).

Table 1. The ¹³C NMR spectroscopic data for the natural N-trans-cinnamoyltyramine and the synthesized N-trans-cinnamoyltyramine.

Position	δ ^13C^a
	Natural	Synthetic
1	154.4	154.3
2	115.5	115.5
3	129.9	129.9
4	130.9	130.9
5	Same as 3	Same as 3
6	Same as 2	Same as 2
7	34.7	34.8
8	40.9	41.0
9	165.6	165.8
10	120.6	120.5
11	141.0	141.1
12	134.8	134.8
13	127.8	127.8
14	128.8	128.8
15	129.6	129.7
16	Same as 14	Same as 14
17	Same as 13	Same as 13

Note: ¹³C NMR spectra of both natural and synthesized NTCT were recorded at 500 MHz on a Bruker Avance DRX500 and AV800 spectrometers equipped with HCN (hydrocyanic acid) triple-resonance cryogenic probe and Z-gradient coil with CDCl₃ (deuterated chloroform) as the solvent.

^aδ values are reported in ppm using solvent as internal standard. For numbering, see Figure 1.

Scheme 2. Proposed biosynthesis pathway of N-trans-cinnamoyltyramine.

Figure 1. N-trans-cinnamoyltyramine.

Figure 2. Analogs of N-trans-cinnamoyltyramine.

Figure 3. Effects of N-trans-cinnamoyltyramine on hypocotyl (shoot) and root growth of cress seedlings. ED₅₀ values represent the effective dose to reduce the representative parameter (shoot or root growth) by 50%. Means followed by the same letter are not significantly different using Duncan’s multiple range test at P ≤ .001).

Figure 4. Effects of N-trans-cinnamoyltyramine on hypocotyl (shoot) and root growth of barnyardgrass seedlings. ED₅₀ values represent the effective dose to reduce the representative parameter (shoot or root growth) by 50%. Means followed by the same letter are not significantly different using Duncan’s multiple range test at P ≤ .001.

Figure 5. ED₅₀ values of N-trans-cinnamoyltyramine on shoot and root growth of cress and barnyardgrass seedlings (results of repeated studies using four replications). Vertical bars indicate the standard error of the means. Means followed by the same letter are not significantly different using Duncan’s multiple range test at P ≤ .001.

Figure 6. Effects of N-trans-cinnamoyltyramine on hypocotyl and root growth of cress (A) and barnyardgrass (B) seedlings following 48 hours of incubation at various concentrations.