Coumarin-Caged Compounds of 1-Naphthaleneacetic Acid as Light-Responsive Controlled-Release Plant Root Stimulators

Abstract

Six coumarin-caged compounds of 1-naphthaleneacetic acid (NAA) comprising different substituents on the coumarin moiety were synthesized and evaluated for their photophysical and chemical properties as light-responsive controlled-release plant root stimulators. The 1H NMR and HPLC techniques were used to verify the release of NAA from the caged compounds. After irradiation at 365 nm, the caged compounds exhibited the fastest release rate at t 1/2 of 6.7 days and the slowest release rate at t 1/2 of 73.7 days. Caged compounds at high concentrations (10–5 and 10–6 M) significantly stimulate secondary root germination while free NAA at the same level is toxic and leads to inhibition of secondary root germination. The cytotoxicity of the caged compounds against fibroblasts and vero cells were evaluated, and the results suggested that, at 10–5–10–6 M, caged compounds exhibited no significant cytotoxicity to the cells. Thus, the caged compounds of NAA in this study could be of great benefit as efficient agrochemicals.

Multiple Roles of Mesoporous Silica in Safe Pesticide Application by Nanotechnology: A Review

“…The developed formulation was only effective for insects with transparent body structure due to the relatively short absorption wavelength of the insecticide. Very recently, coumarin-caged compounds of 1-naphthaleneacetic acid have been synthesized and used as light-responsive plant root stimulators …”

“…Very recently, coumarin-caged compounds of 1-naphthaleneacetic acid have been synthesized and used as light-responsive plant root stimulators. 100 In general, research related to light-responsive pesticide nanoformulations has been rarely reported. The currently developed mesoporous silica-based pesticide nanoformulations primarily feature good photostability to protect the pesticides from photodegradation, rather than the light-responsive characteristics.…”

Caged Phytohormones: From Chemical Inactivation to Controlled Physiological Response

“…In the latest publication on caged-auxins, Keawchangwat presented the synthesis of caged NAA with coumarin-based photoremovable protecting groups (Figure , 6a – 6f ) . Prepared compounds with hydroxy-, chloro-, and methylenedioxy substituents on the coumarin phenyl moiety showed strong fluorescence with an emission wavelength maxima between 425 and 492 nm.…”

“…In the latest publication on caged-auxins, Keawchangwat presented the synthesis of caged NAA with coumarin-based photoremovable protecting groups (Figure 6, 6a−6f). 93 Prepared compounds with hydroxy-, chloro-, and methylene-dioxy substituents on the coumarin phenyl moiety showed strong fluorescence with an emission wavelength maxima between 425 and 492 nm. In vitro photolysis of compounds 6a−6f in 1 M HEPES/MeOH media (20:80) exposed to 365 nm UV light (6 W) resulted in a progressive release of NAA, being the most effective and rapid for 6e (10th day 60% release of NAA) followed by 6a.…”

The mechanism of coumarin inhibits germination of ryegrass (Lolium perenne) and its application as coumarin–carbon dots nanocomposites

“…As an important class of allelochemicals, coumarin compounds have allelopathic effects on many plants 5,6 . which include damage to the cell membrane, abnormalities in hormone levels, and changes in plant cell division and photosynthesis 7–9 .…”