Thirty-one substituted hydrazones of nalidixic acid hydrazide were synthesized and characterized by spectral techniques. These compounds were evaluated for various biological activities, namely, fungicidal, insecticidal, and nitrification inhibitory activities. The antifungal activity was evaluated against five pathogenic fungi, namely, Rhizoctonia bataticola , Sclerotium rolfsii , Rhizoctonia solani , Fusarium oxysporum , and Alternaria porii . They showed maximum inihibition against A. porii with ED(50) = 34.2-151.3 microg/mL. The activity was comparable to that of a commercial fungicide, hexaconazole (ED(50) = 25.4 microg/mL). They were also screened for insecticidal activity against third-instar larvae of Spodoptera litura and adults of Callosobruchus maculatus and Tribollium castaneum . Most of them showed 70-100% mortality against S. litura through feeding method at 0.1% dose. These compounds were not found to be effective nitrification inhibitors.
A number of substituted Schiff bases were synthesized and characterized by (1)H NMR and mass spectrometry. These compounds were screened for antifungal activity in vitro against pathogenic fungi, namely, Sclerotium rolfsii and Rhizoctonia bataticola, and for their effect on nitrification inhibition under laboratory conditions. Maximum antifungal activity was exhibited by (2,4-dichlorobenzylidene)-(2,4,5-trichlorophenyl)-amine and (3-nitrobenzylidene)-(2,4,5-trichlorophenyl)-amine against both fungi (ED(50) with range from 3 to 24 microg/mL). Maximum nitrification inhibition (NI) was exhibited by (2,4-dichlorobenzylidene)-(2-fluorophenyl)-amine, (4-fluorophenyl)-(3-nitrobenzylidene)-amine, (2,6-dichlorobenzylidene)-(4-fluorophenyl)-amine, and (2,6-dichlorobenzylidene)-(3 fluorophenyl)-amine (NI in the range 91-96%).
Novel nalidixic acid-based 1,3,4-thia(oxa)diazoles, their thio ethers, sulfones, bis mercapto, and Mannich bases were synthesized and characterized by Infrared spectra, 1 H NMR,
13C NMR, and elemental analysis. These compounds were evaluated for their antibacterial activity against two Gram-positive and three Gram-negative bacteria. The preliminary bioassay showed that most of the compounds had better antibacterial activity than the parent compounds, 1,3,4-thia(oxa)diazoles, at the dosage 50 lg ⁄ mL toward five test bacteria. Four Mannich bases of nalidixic acid-based 1,3, 4-thiadiazole exhibited maximum antibacterial activity against Bacillus subtilis, Klebsiella pneumoniae, and Pseudomonas aeruginosa with minimum inhibitory concentration in the range of 6.25-125 lg ⁄ mL.
The study revealed that a few compounds possessed good activity against three different pests namely certain fungus, soil bacteria and insect, among which, compound 37 (R' = 4-chlorophenyl) behaved the best.
Background
Application of nanotechnology for crop protection in the form of nanopesticide has attracted significant interest in modern agriculture for the management of devastating polyphagous pests. In the present work, highly stable, ready-to-use water-based nanoformulations of hydrazine-based pesticides were evaluated for their Insect Growth Regulatory potential against the polyphagous insect pest—Spodoptera litura. Also, the nanoformulations were screened for their antifungal behaviour against plant pathogenic fungi; Colletotrichum gloeosporioides, Rhizoctonia solani, Fusarium solani, and Alternaria solani.
Results
Nanoformulation of sulfonyl acyl hydrazine derivative, NF7, emerged as the best insect growth regulator with GI90 value 0.010 mg L−1 followed by NF4 and NF6 with GI90 0.012 and 0.013 mg L−1, respectively. Results of diet incorporation method showed enhanced efficacy of nanoformulations when compared with topical application method. Antifungal screening showed that many nanoformulations displayed at least 50% growth inhibition for treatment dosage 50–200 mg L−1 against the fungal pathogens tested (C. gloeosporioides, R. solani, F. solani, and A. solani). NF6, NF7, and NF8 were more potent antifungal agents at lower treatment dosages, while at high doses (400 and 800 mg L−1), 100% growth inhibition at concentration was observed against R. solani and F. solani, except NF1 having 64% growth inhibition against F. solani.
Conclusion
Results presented here are very promising and deliver new nanoformulations of diacyl and sulfonyl acyl hydrazine-based derivatives to be employed as nanopesticide for sustainable crop protection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.