Indigo as a Plant Growth Inhibitory Chemical from the Fruit Pulp of Couroupita guianensis Aubl.

Abstract

Weed management is an important issue since weeds directly compete with crop plants for space, nutrients; serve as habitat for insect pests and diseases, and can create a significant annual reduction in crop productivity. This study focused on evaluating the contribution of the secondary metabolites of the fruit pulp of Couroupita guianensis Aubl. for its potential growth inhibitory effect. Crude extracts of C. guianensis fruit pulp were collected with different solvents and applied to test plants in petri dishes. The crude extracts of methanol and 1% dimethyl sulfoxide (DMSO) showed potential growth inhibitions with the 50% effective concentration (EC50) of 223 and 229 µg/mL in the bioassay experiment. In the greenhouse pot experiment, soil incorporated with oven-dried fruit pulp of C. guianensis was evaluated on cultivated plant species including Lactuca sativa L., Trifolium repens L., Medicago sativa L., Lolium multiflorum Lam., and Phleum pratense L. The incorporation of dried fruit pulp of C. guianensis into soil reduced shoot and root lengths and the germination percentage of test plants. It was observed that the monocot plants were more affected than the dicot plants. The fruit pulp of C. guianensis was subjected to reversed-phase high-performance liquid chromatography (HPLC) analysis to identify the active compounds. Indigo, identified as one of the candidate compounds of the C. guianensis, had high specific activity (i.e., strong inhibitory activity) in a phytotoxicity bioassay and could explain through the total activity concept the growth inhibitory effect of the C. guianensis on test plants. The results suggested that indigo has plant growth inhibitory effect, indicating the allelopathic potential of C. guianensis, which could be exploited in sustainable weed management.

Biogenic Synthesis and Characterization of Antioxidant and Antimicrobial Silver Nanoparticles Using Flower Extract of Couroupita guianensis Aubl.

“…This AgNP preparation had an approximate diameter of 4.5 nm with a spherical shape, which indicated that it was a good model to accurately describe the AgNP atomistic structure and its interactions with the molecules in the plant extract. To load the AgNP with the molecules commonly found in the plant extract of C. guianensis, we chose five molecules whose atomistic structures are reported in Figure 2: Couroupitine A, indigo, idirubin, nerol and isatin [51]. The structure of the AgNP obtained in the first step was inserted into the center of an empty cubic box that was 9 nm in size.…”

“…The obtained box was then filled with SPC water [52]. The system was simulated at 300 K for 100 ns while the Ag atoms positions were kept frozen, as was carried out previously [51][52][53][54]. The Gromos 54a7 force field was employed for the simulation of the adsorption of molecules over the AgNP surface [55][56][57].…”

“…The parameters for the molecules were retrieved from the Automated Topology Builder (ATB) [58] and the parameters for the AgNP were obtained from the work of Heinz et al [59]. The combination of these parameters has already been employed with good results for Au and Ag NPs [51][52][53][54]60]. All simulations were performed with the LAMMPS package [61] and the timestep used was 0.1 fs.…”

“…The XRD pattern was computed using the PLUMED package [64] and XRD script developed by Lodesani et al [65]. To load the AgNP with the molecules commonly found in the plant extract of C. guianensis, we chose five molecules whose atomistic structures are reported in Figure 2: Couroupitine A, indigo, idirubin, nerol and isatin [51]. The structure of the AgNP obtained in the first step was inserted into the center of an empty cubic box that was 9 nm in size.…”

Electrochemical Fingerprint Biosensor for Natural Indigo Dye Yielding Plants Analysis

“…Indigo was used to dye silk fabrics unearthed from the Western Han Dynasty tomb in Mawangdui, Changsha. Silk and cotton printing and dyeing products of the Tang Dynasty are preserved in Shosakura in Xinjiang and Japan, including batik cotton fabric with blue background and white flower [ 9 , 10 , 11 , 12 ].…”