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Subject: Chemistry × End date: 2018 × Start date: 2018 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Chemical derivatization and biological evaluation of major constituent of ajwain (Trachyspermum ammi L.)
    (Punjab Agricultural University, Ludhiana, 2018) Gaba, Jyoti; Sharma, Sunita
    Ajwain is a herbal plant with important medicinal properties. In the present study, chemical composition of essential oil of two types of ajwain seeds (small and bold) has been determined with GC-MS analysis. Thymol (72.03, 71.80%) was found to be the major constituent followed by γ-terpinene (13.53%) and p-cymene (14.16%) in small and bold seeds respectively. Proximate composition studies estimated percentage of nutrients viz. protein (15.01, 12.81), total minerals (12.28, 6.26), moisture (30.90, 6.67), fat (6.10, 13.05), fibre (21.50, 25.30) and carbohydrates (31.21, 35.91) in small and bold seeds respectively. Specific mineral composition analysis showed phosphorus (0.13, 0.126) and potassium (1.03, 1.09) in per cent whereas Fe (560, 221), Zn (59.60, 56.40), Cu (2.30, 3.80) and Mn (76.80, 61.30) were detected in ppm. Various phytochemicals viz alkaloids, saponins, steroids, tannins, coumarins, flavonoids, phytosterols, phenols, chalcones and glycosides were present in different solvent extracts in both types of ajwain. Out of thymol and ajwain oil, former was found to be more effective antioxidant at all the tested concentrations. Different derivatives of thymol viz. formylated thymol (II), chalcone (III), pyrazoline derivatives (IV-VIII), dihydropyrimidinone (IX), mannich bases (X-XII), azo derivatives (XIII-XVIII), imine derivatives (XIX-XXI), thymol hydrazide (XXII), oxadiazole derivative (XXIII), triazole derivative (XXIV), hydrazones (XXV-XXVII), β-lactam derivatives (XXVIII-XXX) were synthesized. All synthesized compounds were characterized by their IR, 1H NMR and 13C NMR spectra. Ajwain essential oil, thymol and its derivatives were screened for antifungal activity against fungi viz. Fusarium moniliforme, Rhizoctonia solani, Dreschlera maydis and insecticidal activity against stored grain pest of chickpea Callosobruchus chinensis. Compounds II, XX and XXI were found to be the most effective compounds against all three tested fungi and insect. None of the synthesized compounds exhibited better antifungal activity as compared to standards.
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    ThesisItemOpen Access
    Isolation, chemical derivatizations and biological activities of sesquiterpenolides from chicory and costus roots
    (Punjab Agricultural University, Ludhiana, 2018) Ravinder Singh; Chahal, K.K.
    The dissertation incorporates the Isolation, chemical derivatizations and biological activities of sesquiterpenolides from chicory and costus roots. The roots of chicory/costus were room dried and extracted by Soxhlet extractor using sequential extraction method with hexane, dichloromethane and methanol as the solvents. GC-MS analysis showed the presence of 22 and 35 compounds in chicory and costus hexane extracts. Isoalantolactone, dehydrocostus lactone and alantolactone were isolated as pure compounds from root extracts via extensive column chromatography over silica gel. Reduction of these isolated compounds was carried out using sodium borohydride. Allylic oxidation of isoalantolactone and dehydrocostus lactone was carried out selenium dioxide-TBHP and selenium dioxide impregnated silica gel-TBHP. Decomposition of pyrazoline derivatives of sesquiterpene lactones under heat, microwave and thermo-sonication were carried out. Chicory/costus root extracts, isolated and derivatized compounds were tested for in vitro antioxidant and antifungal activities against three rice pathogens at different concentrations. The antioxidant potential was evaluated using five different methods viz. DPPH, Hydroxyl, Nitric oxide, superoxide radical scavenging and FRAP assay methods. All the extracts showed promising antioxidant and antifungal activity. Methanol extract of chicory was most active amongst all tested extracts whereas dihydroxy dehydrocostus lactone was the most active sesquiterpenolide amongst tested compounds. Antifungal activity of hexane extract was better than all tested extracts. Isoalantolacone was most effective sesquiterpenoid out of all isolated and derivatized compounds. Field evaluation of bioactive extract revealed that chicory and costus roots hexane extracts were highly effective in controlling disease under field conditions.
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    ThesisItemOpen Access
    Physico-chemical studies on synthesized graphene oxidemagnesium ferrite based nanocomposites and their adsorption potential for Ni (II) ion
    (Punjab Agricultural University, Ludhiana, 2018) Navneet Kaur; Manpreet Kaur
    Role of magnetic nanocomposites for the remediation of waste-water is a thrust area of research. In the present study, hybrid graphene oxide (GO) based inverse spinel magnesium ferrite (MgFe2O4) nanocomposites (NCs) with bentonite/charcoal/chitosan were synthesized using facile sonication method. p-XRD patterns confirmed the presence of spinel ferrite phase in the NCs with the crystalline size 8-32 nm. FT-IR spectra displayed absorption bands corresponding to GO, MgFe2O4 NPs and bentonite/charcoal/chitosan in the NCs along with red shift of bands corresponding to C=O, C=C and O-H stretching. TGA confirmed higher stability of NCs over pristine GO. MgFe2O4 NPs imparted appreciable saturation magnetization to the NCs (4.03-11.10 emug-1). SEM and TEM revealed high porosity and immobilization of clusters of MgFe2O4 NPs onto GO sheets in the NCs. BET surface area of the NCs ranged from 58.34 to 165.29 m2g-1 and was markedly higher than pristine MgFe2O4 NPs. Removal of Ni (II) ions was studied by batch adsorption method. Langmuir, Temkin and Freundlich models were followed in perfect way. Maximum adsorption capacity from Langmuir model ranged between71.43-111.11 mgg-1 for NCs. Kinetic data fitted pseudo-second-order equation. Thermodynamic parameters revealed spontaneous and endothermic removal using NCs; whereas using GO the removal was exothermic. Percentage removal of Ni (II) was maximum for MgFe2O4 NPs and their binary NCs with GO. Effect of co-existing ions on Ni (II) adsorption was studied in Pb-Cd-Ni-Zn system. NCs possessed higher removal potential for Pb (II) as compared to Ni (II) due to the lower hydration energy of the former. For electroplating waste-water the optimum adsorbent dose required for complete metal ion removal was higher than that for spiked water because of presence of other interfering ions.
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    ThesisItemOpen Access
    Chemistry of sesquiterpenoids from essential oil of Cyperus scariosus and their antioxidant and antifungal potential
    (Punjab Agricultural University, Ludhiana, 2018) Amit Kumar; Chahal, K.K.
    The present investigation deals with Chemistry of sesquiterpenoids from essential oil of Cyperus scariosus and their antioxidant and antifungal potential. The roots of C. scariosus were grounded and subjected to hydro-distillation using Clevenger apparatus to extract the essential oil. The essential oil was analysed by gas chromatography-mass spectrometry. A total of 30 compounds, accounting for 93.30 % of the total essential oil, were identified. Longiverbenone, nootkatone, caryophyllene oxide and cyperene were found to be the major compounds present. The C. scariosus roots were also extracted by Soxhlet extractor using three different solvent i.e. hexane, dichloromethane and methanol. Total of 55, 67 and 25 compounds were present in hexane, dichloromethane and methanol extracts respectively. Cyperene, isolated from essential oil was chemically derivatized into cyperotundone, cyperene alcohol, cyperenol, cyperenal and cyperene epoxide. The structures of the compounds were elucidated on the basis of FTIR, 1H NMR and 13C NMR spectroscopy. C. scariosus essential oil, various extracts, isolated and derivatized compounds were tested for antifungal and antioxidant activities at different concentrations viz.0.05, 0.1, 0.25, 0.5 and 1.0 mg/mL respectively. All the extracts and essential oil showed significant antifungal activity. Essential oil was most active as compared to other tested components against all plant pathogens. The antioxidant activity of C. scariosus essential oil, various extracts, isolated and derivatized compounds was carried out in vitro using involving 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging potential, inhibition of nitric oxide radical generation and ferric reducing antioxidant power assay. Methanol extract of C. scariosus showed highest antioxidant activity in all the methods tested as compared to essential oil, hexane and dichloromethane extracts. Cyperenol showed highest antioxidant activity as compared to isolated and derivatized compounds.