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20214
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Subject: Chemistry × End date: 2021 × Start date: 2021 × Thesis Type: Ph.D ×
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    Synthesis and derivatization of substituted 3,5-dimethoxy-4-hydroxy benzaldehydes and their biological activities
    (Punjab Agricultural University, Ludhiana, 2021) Sahni, Tanvi; Sharma, Sunita
    Naturally occurring phenolic aldehyde 3,5-dimethoxy-4-hydroxybenzaldehyde (syringaldehyde) was derivatized to synthesize compounds like Schiff Bases (I-IX), β-lactams (X-XI), azo derivatives (XII-XV), hydrazones of azo derivatives (XVI-XXVII), hydrazones (XXVIII-XXXI), thiosemicarbazones (XXXII- XXXIII), ,β-unsaturated compounds (XXXIV-XXXVIII) and esters (XXXIX-XLIX). Characterization of synthesized compounds was done using UV-visible, FT-IR, 1H and 13C NMR. All the synthesized compounds were evaluated for antioxidant potential i.e. DPPH, FRAP and Phosphomolybdate assay), microbial potential against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Klebsiella sp. and Enterobacter sp. and fungicidal potential against four pathogenic fungi of maize against Rhizoctonia solani, Dreschlera maydis, Fusarium verticillioides and Macrophomina phaseolina. In the DPPH assay, syringaldehyde and compounds (VI, VII, XXXVIII and XXXIX) were more effective than standard BHT while none of the compound was more effective than standard ascorbic acid. In FRAP assay, compounds (VII, X, XI, XVIII, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII) were effective than ascorbic acid and BHT standards while none of the compound was more effective than ascorbic acid in terms of phosphomolybdate assay. Compounds (VIII, X, XI, XV, XXI, XXIV and XXXIX) were more effective than ampicillin against B. subtilis. Compounds (I, II, III, VI, VIII, IX, X, XI, XII, XIII, XIV, XV, XVIII, XXI, XXII, XXIII, XXIV, XXV, XXVII and XXXIX) showed greater zone of inhibition than ampicillin against P. aeruginosa. Microbial potential at par with ampicillin against E.coli was showed by compounds (VIII, XI, XXI and XXII). Four compounds (XV, XXI, XXII and XXVI) were more effective than ampicillin against Enterobacter sp. while none of compound was found more effective than ampicillin against Klebsiella sp. Antifungal potential of Compound (VI) was found at par with carbendazim 50 WP against R. solani. Mycelial growth of D. maydis was inhibited by fourteen compounds more than carbendazim 50 WP but less than Mancozeb 75 WP. None of the compound was effective than carbendazim 50 WP against F. verticillioides and M. phaseolina.
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    ThesisItemOpen Access
    Evaluation of synthesized ferrite nanocomposites with N-doped graphene and carbon microspheres for the removal of heavy metals and organic pollutants
    (Punjab Agricultural University, Ludhiana, 2021) Manmeet Kaur; Manpreet Kaur
    Magnetic ferrites and their nanocomposites with nitrogen doped graphene oxide (N-GO) and hollow mesoporous silica have received immense interest as adsorbents and photocatalysts for water decontamination. This work reports facile strategy for the synthesis and evaluation of N-GO, MFe2O4 NPs (M= Mg, Ca), MFe2O4-NGO (M= Mg, Ca) and hollow mesoporousnanocomposites for the removal of Pb(II), Ni(II), As(III), CR dye and PNP from contaminated water.NCs of NGO with MFe2O4 NPs were prepared using ultra sonication method. For dual core shell nanocomposite, hollow mesoporous SiO2 core was synthesized using polyethylene glycol (PEG) and cetyltrimethyl ammonium bromide (CTAB) as cotemplates. Synthesized SiO2 was used as template over which MgFe2O4 NPs were loaded using sodium dodecyl sulphate (SDS) as a surfactant to synthesize MgFe2O4@SiO2 core-shell nanocomposite. This nanocomposite was further loaded with N-GO in order to design NGO@MgFe2O4@SiO2 dual core nanocomposite by ultra sonication method. Structural, magnetic and surface properties of the nanocomposites were analyzed using various physicochemical techniques. The effectiveness of NPs and nanocomposites for the removal of Pb(II), Ni(II) and As(III) and photodegradation of CR and PNP was studied.MgFe2O4@SiO2 displayed maximum heavy metal removal whereas, NGO@MgFe2O4@SiO2 dual corenanocomposite exhibited maximum photocatalytic degradation for organic pollutants. The mechanism of adsorption and photocatalysis from spiked water was investigated by batch experiment studies.The adsorption data was best fitted into Langmuir adsorption isotherm and followed pseudo-second-order kinetic model.The degradation mechanism for CR and PNP was proposed on the basis of mass spectrometric analysis of products formed during photodegradation. Also, the comparative photocatalytic activity of spiked distilled water and contaminated water revealed reduction in photocatalysis of 17% and 22% in the contaminated water. The synthesis of NCs of MgFe2O4 NPs with doped carbon material and core-shell synthesis using SiO2 core provide new synthetic strategy for further modification of pristine ferrite NPs for future applications.
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    ThesisItemOpen Access
    Chemical derivatizations of major constituent of cumin (Cuminum cyminum) and their biological activity
    (Punjab Agricultural University, Ludhiana, 2021) Pardeep Kaur; Sharma, Sunita
    Cuminum cyminum is an annual herbaceous plant belonging to the family Apiaceae genus Cuminum. In the present study, chemical composition of essential oil and different solvent extracts of cumin of variety GC-4 was determined by GC-MS analysis. Cuminaldehyde was found to be the major constituent present in the essential oil and second major compound present in the different solvent extracts (except chloroform). The proximate analysis of cumin seeds showed that it contains 8.58±0.20, total minerals 8.62±0.05, crude protein 14.43±0.02, crude fibre 11.06±0.01, fats 15.00±0.04, total sugars 2.30±0.21 and total carbohydrates 40.01±0.06. Elemental investigation of cumin seeds showed that it contains micronutrients like Iron: 181.33, copper: 14.25, manganese: 25.75, zinc: 31.25, chromium: 10.15, nickel: 2.38, cobalt: 2.05, cadmium: 2.03, lead: 58.75, arsenic: 118.50 in parts per million concentrations. Phytochemical study revealed that various phytochemicals viz alkaloids, saponins, tannins, coumarins, amino acids, flavonoids, proteins, phenols and carbohydrates were present in different solvent extracts. Aqueous extract of cumin seeds was used as a bioreductant for the synthesis of silver nanoparticles. Different derivatives i.e. Schiff Bases, hydrazones, thiosemicarbazones, chalcones and pyrazolines of major constituent of essential oil namely cuminaldehyde (isolated from essential oil by column chromatography) were synthesized. Characterization of synthesized compounds was done using UV-visible, FT-IR, 1 H and 13C NMR. Essential oil, different solvent extracts, silver nanoparticles, cuminaldehyde and its derivatives were screened for their antioxidant (via DPPH assay), microbial (against Pseudomonas sp., Klebsiella sp. and Enterobacter sp.) and fungicidal potential (against Fusarium wilt, Ascochyta blight and Bortrytis gray mould. Cuminaldehyde derivatives were found more effective as compared to cumin essential oil, its major constituent, different solvent extracts of cumin seeds and silver nanoparticles synthesized from aqueous cumin seed extract.
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    Regioselective elaboration of isatin and their biological activity studies
    (Punjab Agricultural University, Ludhiana, 2021) Komalpreet Kaur; Utreja, Divya
    Regioselective elaboration of isatin at N-1 and C-3 position were carried out using different reagents. The synthesized isatin derivatives (2a-g and 4a-f) were characterized by 1HNMR, 1 HNMR-D2O, 13CNMR, FT-IR spectroscopies, mass spectrometery and elemental analysis. In vitro biological evaluation of synthesized isatin derivatives as antioxidant, antimicrobial and nematicidal agents had been carried out. The antioxidant evaluation using different models revealed that the compounds 1-decyl-indoline-2,3-dione (2g) and 3-heptyl-3-hydroxyindolin-2-one (4f) exhibited potent antioxidant potential due to the increase of electron donating character. The antimicrobial and nematicidal activity against Pseudomonas aeruginosa, Pseudomonas oryzihabitans, Xanthomonas campestris and Meloidogyne incognita pathogenic organisms revealed that the compounds isatin (1), 1-propyl-indoline-2,3-dione (2a) and 3-ethyl-3-hydroxyindolin-2-one (4a) exhibited potent inhibition potential against these pathogenic organisms as compared to other tested compounds. The in vitro results were further validated through in vivo studies on tomato and in silico studies which revealed that the tested compounds during investigation had shown novel interaction with the target binding sites and resulted in potent biological activity.