SYNTHESIS, SPECTRAL CHARACTERIZATION, AND IN-VITRO ANTIOXIDANT ACTIVITY SCREENING OF SOME NOVEL 2-HYDROXY QUINOLINE DERIVATIVES
HTML Full TextSYNTHESIS, SPECTRAL CHARACTERIZATION, AND IN-VITRO ANTIOXIDANT ACTIVITY SCREENING OF SOME NOVEL 2-HYDROXY QUINOLINE DERIVATIVES
Pradeep Kumar M. R. * and Hunashal R. D.
Department of Pharmaceutical Chemistry, KLE College of Pharmacy, A Constituent Unit of KLE Academy of Higher Education and Research [KAHER], Hubli, Karnataka, India.
ABSTRACT: In an attempt of synthesizing some novel and potent antioxidant activity having compounds, here some novel quinoline derivatives are reported. Initially using Vilsemeir-Hack reagent method 7-methyl or 8-methyl substituted 2-cholro-3-formylquinolines (Ia, b) were prepared. Further 7-methyl or 8-methyl substituted 2-hydroxy quinoline-3-carbaldehyde (IIa, b) were synthesized by the reaction of compound (I) on microwave irradiation with 4M HCl, which on further treatment with different substituted hydrazides yielded the novel Schiff bases of quinoline III (a-f). Purity of the synthesized compounds was determined by TLC and melting point. The structure of all newly synthesized compounds was confirmed by spectral studies such as IR, 1H NMR, 13C NMR, and mass spectroscopy. All the synthesized compounds were screened for in-vitro antioxidant activity by free radical scavenging activity by DPPH assays method and ferric ion reduction method using ascorbic acid as the standard drug. Screening results showed that all compounds are exhibiting moderate to good activity. Especially compounds III b, III d, and III f showed significant antioxidant activity.
Keywords: Quinoline, Antioxidant, DPPH method, Ferric ion reduction method, Ascorbic acid
INTRODUCTION: Oxidation processes are essential for the energy management of all living organisms and are therefore maintained under strict control by several cellular mechanisms 1. Free radicals are molecules, ions, or atoms with unpaired electrons in their outermost shell of electrons 2. These are constantly formed in human body, can become toxic when generated in excess or during the deficiency of naturally occurring antioxidant defenses. High levels of free radicals can cause damage to biomolecules such as lipids, proteins, enzymes and DNA in cells and tissues.
This may result in many diseases such as cancer, diabetes, cardiovascular, autoimmune diseases, neurodegenerative disorders and other diseases through the violent reactivity of the free radicals 3-5. Antioxidants are important compounds that reduce or neutralize the free radicals, thus protecting the cells from oxidative injury 6. Therefore, considerable research has been directed towards the development and identification of new antioxidants to prevent radical-induced damage.
Quinoline ring system is a ubiquitous pharma-cophore and an essential structural fragment of a large number of natural and synthetic compounds possessing versatile pharmacological activities like antidiabetic 7, anti-HIV 8, antioxidant 9, anti-inflammatory 10, antifungal 11, antimicrobial 12,13, antihypertensive 14, analgesic 15, antiparasitic 16, antitubercular 17, 18, 19, antiviral 20, anticonvulsant 21, 22, antimalarial 23, anticancer 24, 25, 26, etc. These results encouraged us to synthesize some novel quinoline derivatives for antioxidant activity.
In continuation of our research work on quinolines to explore their potent therapeutic properties 27, 28, 29, here we have reported the synthesis, spectral characterization, and in-vitro antioxidant screening of some novel quinoline derivatives.
In this research work, initially, compounds I (a, b) were synthesized by the microwave irradiation of 7 or 8-substituted-2-cholro-3-formylquinolines with 4M HCl. IR spectra of these compounds showed characteristic peaks at around 3180 cm-1 (OH), 1680 cm-1 (C=O), 1600 cm-1 (C=N), Further a novel series of quinoline derivatives III (a-f) were synthesized by the reaction between compounds II (a, b) and different hydrazides. IR spectra of these compounds showed characteristic peaks at around 3400 cm-1 (OH), 3100 cm-1 (NH), 1660 cm-1 (C=O), 1600 cm-1 (C=N). 1H NMR spectra of these compounds showed characteristic peaks at around δ 2.1, 8.32 and 12.24 ppm due to protons of CH3, CH=N, and OH respectively. 13 C NMR spectra of these compounds showed characteristic peaks at around δ 22, 135, and 160 ppm due to carbon of CH3, CH=N, and C=O respectively.
MATERIALS AND METHODS:
General Considerations: The various chemicals used in the synthesis of the titled compounds were purchased from Sigma-Aldrich Pvt. Ltd, Spectrochem Pvt. Ltd, S.D. Fine Chem Pvt. Ltd. Absolute ethanol and DMF utilized were purified according to the literature.
Melting points of all synthesized compounds were determined by open capillary method and are uncorrected. FTIR spectra were recorded on Bruker Alpha-T by using KBr pellets. The 1HNMR were recorded on Bruker Avance II NMR 400 MHz instruments using DMSO as solvent and TMS as internal standard; chemical shifts are expressed as δ values (ppm). Elemental analysis was carried out for the synthesized compounds. All the physicochemical data are given in Table 1.
Antioxidant Activity Screening:
Free Radical Scavenging Activity by DPPH Assays Method: 30 DPPH (1, 1-diphenyl-2-picryl-hydrazil) is stable free radical. Methanol solution of DPPH is used to evaluate the antioxidant activity of several synthetic compounds. Antioxidant on interaction with DPPH, both transfer electron or hydrogen atom to DPPH, thus neutralizing its free radical character and convert it to1, 1-diphenyl-2-picryl hydrazine. The degree of discoloration indicates the scavenging activity of the drug. The change in absorbance produced at 517 nm has been used as a measure of its antioxidant activity. For this method 10, 20, 30, 40, 50 μg/ml concentrations of ligands and ascorbic acid were prepared. From this stock solution, 1ml has been pipette out, and 5ml methanol solution of DPPH was added, shaken well, and the mixture was incubated at 37 °C for 30 min absorbance of all samples measured against blank 517 nm. The absorbance of the DPPH reagent alone was taken as control. The % radical scavenging activity can be calculated following formula:
% free radical Scavenging activity = Absorbance of control - Absorbance of sample × 100 / Absorbance of control
All the synthesized compounds were subjected to anti-oxidant activity screening using this method, and results are shown in Table 2.
Ferric Ion Reduction Method: 31 The reaction mixture containing 1, 10-o-phenanthroline (0.5 mL), ferric chloride 1mL (0.02 mM) and test compound (solution of different concentration of synthesized compounds and ascorbic acid as standard drug) in a final volume of 5 mL with methanol was incubated for 15-20 min at ambient temperature and absorbance was measured at 510 nm. In another set, sodium dithionate (0.3 mM) was added instead of the compounds, and absorbance was taken as equivalent to 100% reduction of all the ferric ions present.
Anti-oxidant activity by ferric ion reduction method can be calculated by the following formula:
% Activity = [At /As] × 100
Where, As = absorbance by standard drug solution at 510 nm; At = absorbance by the sample solution at 510 nm.
All the synthesized compounds were subjected for anti-oxidant activity screening using this method and results are shown in Table 3.
SCHEME
RESULTS:
General Procedure for the Synthesis of 7/ 8-methyl-2-hydroxyquinoline-3-carbaldehyde II (a, b): A mixture of 7 or 8-methyl-2-chloro-3-formylquinolines (0.01 mol) and 4M HCl solution (30 ml) was subjected for Microwave irradiation (120 W) for 6 min. Yellow solid was precipitated on cooling. This was poured into a beaker containing crushed ice (80 g), filtered, dried, and recrystallised from glacial acetic acid.
II a: IR (KBr) cm-1: 3190.12 (OH), 1601.03 (C=O), 1622.14 (C=N). 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.13 (s, 3H, CH3), 7.21 (d, 1H, C6-H of quinoline), 7.42 (d, 1H, C8-H of quinoline), 7.90 (d, 1H, C5-H of quinoline), 8.38 (s, 1H, C4-H of quinoline), 10.26 (s, 1H, CHO), 12.63 (s, 1H, OH). Mass (m/z): 187.19
II b: IR (KBr) cm-1: 3189.11 (OH), 1684.76 (C=O), 1621.17 (C=N). 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.1 (s, 3H, CH3), 7.28 (d, 1H, C6-H of quinoline), 7.51 (d, 1H, C8-H of quinoline), 7.89 (d, 1H, C5-H of quinoline), 8.32 (s, 1H, C4-H of quinoline), 10.43 (s, 1H, CHO), 12.25 (s, 1H, OH).
Mass (m/z): 187.19.
General procedure for the synthesis of compounds III (a-f): A mixture of compound II (a, b) (0.005 mol) in 25 ml of absolute ethanol, substituted hydrazides (0.005 mol), and a catalytic amount of glacial acetic acid was added. The mixture was refluxed for 6 h. A solid compound was obtained on cooling the reaction mixture. It was filtered, dried, and recrystallized from ethanol and DMF mixture to get the final compounds III (a-f).
III a: IR (KBr) cm-1: 3406.16 (OH), 3159.24 (NH), 1649.61 (C=O), 1604.17 (C=N). 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.18 (s, 3H, CH3), 7.35 - 8.38 (m, 9H, C4, C5, C6, C8-H of quinoline, CH=N & C2, C3, C5, C6-H of pyridine), 12.09 (s, 1H, NH), 12.31 (s, 1H, OH). Mass (m/z): 306.32
III b: IR (KBr) cm-1: 3406.37 (OH), 3159.33 (NH), 1644.21 (C=O), 1615.18 (C=N), 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.19 (s, 3H, CH3), 7.34 (s, 2H, C3 & C4-H of pyridine), 7.48 (s, 1H, C8-H of quinoline), 7.77 (s, 2H, C2 & C5-H of pyridine), 7.86 (s, 1H, C6-H of quinoline), 8.13 (s, 1H, C5-H of quinoline), 8.34 (s, 1H, CH=N), 8.55 (s, 1H, C4-H of quinoline), 11.68 (s, 1H, NH), 12.26 (s, 1H, OH). 13C NMR (400 MHz, DMSO-d6, δ ppm): 22.08 (CH3), 161.98 (quinoline- C2), 160.16 (C=O), 151.30 (quinoline C9), 145.26 (CH=N), 141.75 (pyridine- C4), 136.43 (quinoline- C4), 131.62 (quinoline- C7), 127.58 (pyridine- C3 and -C5), 126.03 (quinoline- C5), 122.18 (pyridine- C2 and -C6), 121.39 (quinoline- C8), 120.55 (quinoline- C6), 118.32 (quinoline- C10), 115.36 (quinoline- C3). Mass (m/z): 306.11
III c: IR (KBr) cm-1: 3410.17 (OH), 3106.34 (NH), 1681.02 (C=O), 1613.05 (C=N), 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.13 (s, 3H, CH3), 7.35 (d, 1H, C8-H of quinoline), 7.41 (d, 1H, C6-H of quinoline), 7.56 (s, 1H, C5-H of quinoline), 8.35(s, 1H, C4-H of quinoline), 8.59(s, 2H, NH2), 8.76(s, 1H, CH=N), 11.24 (s, 1H, NH), 12.31 (s, 1H, OH). Mass (m/z): 260.07
III d: IR (KBr) cm-1: 3414.22 (OH), 3136.17 (NH), 1658.38 (C=O), 1605.94 (C=N), 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.12 (s, 3H, CH3), 7.36 (d, 1H, C8-H of quinoline), 7.47 (d, 1H, C6-H of quinoline), 7.58 (s, 1H, C5-H of quinoline), 8.29 (s, 1H, C4-H of quinoline), 8.62 (s, 2H, NH2), 8.79 (s, 1H, CH=N), 11.52 (s, 1H, NH), 12.19 (s, 1H, OH).Mass (m/z): 260.31
III e: IR (KBr) cm-1: 3412.44 (OH), 3109.38 (NH), 1643.25 (C=O), 1611.36 (C=N), 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.1 (s, 3H, CH3), 7.25 (s, 2H, C3 & C4-H of pyridine), 7.38 (s, 1H, C8-H of quinoline), 7.64 (s, 2H, C2 & C5-H of pyridine), 7.80(s, 1H, C6-H of quinoline), 7.97 (s, 1H, C5-H of quinoline), 8.58 (s, 1H, CH=N), 8.85 (s, 1H, C4-H of quinoline), 11.18 (s, 1H, NH), 12.24 (s, 1H, OH). Mass (m/z): 306.28
III f: IR (KBr) cm-1: 3419.66 (OH), 3143.20 (NH), 1642.53 (C=O), 1621.08 (C=N), 1H NMR (400 MHz, DMSO-d6, δ ppm): 2.14 (s, 3H, CH3), 7.45-8.78 (m, 9H, C4, C5, C6, C8-H of quinoline, CH=N & C2, C3, C5, C6-H of pyridine), 11.25 (s, 1H, NH), 12.42 (s, 1H, OH).13C NMR (400 MHz, DMSO-d6, δ ppm): 22.13 (CH3), 162.39 (quinoline- C2), 161.43 (C=O), 150.98 (quinoline C9), 141.88 (CH=N), 139.62 (pyridine- C4), 137.04 (quinoline- C4), 131.28 (quinoline- C7), 128.06 (pyridine- C3 and -C5), 122.02 (quinoline- C5), 122.13 (pyridine- C2 and -C6), 121.88 (quinoline- C8), 120.52 (quinoline- C6), 118.34 (quinoline- C10), 115.96 (quinoline- C3). Mass (m/z): 306.14
TABLE 1: PHYSICO-CHEMICAL DATA OF THE SYNTHESIZED COMPOUNDS III (a-f)
Compound | Molecular formula | M.P °C | %Yield | Solubility |
III a | C17H14N4O2 | 256-258 | 64 | DMSO |
III b | C17H14N4O2 | 236-238 | 58 | DMSO |
III c | C17H14O3S | 228-230 | 70 | DMSO |
III d | C17H14N4OS | 270-272 | 66 | DMSO |
III e | C17H14N5O4 | 262-264 | 59 | DMSO |
III f | C17H14 N5O4 | 244-246 | 62 | DMSO |
TABLE 2: IN-VITRO ANTIOXIDANT ACTIVITY SCREENING RESULTS OF NEWLY SYNTHESIZED COMPOUNDS III (a-f) BY DPPH RADICAL SCAVENGING ASSAY
S. no. | Compound | Mean abs ± S.E.M | % inhibition |
1 | III a | 0.5230±0.0012 | 56.20 |
2 | III b | 0.5120±0.0014 | 59.10 |
3 | III c | 0.5530±0.0008 | 52.60 |
4 | III d | 0.5996±0.0009 | 58.80 |
5 | III e | 0.5328±0.0010 | 52.10 |
6 | III f | 0.5410±0.0006 | 57.30 |
7 | Ascorbic acid | 0.5260±0.05 | 68.50 |
TABLE 3: IN-VITRO ANTIOXIDANT ACTIVITY SCREENING RESULTS OF NEWLY SYNTHESIZED COMPOUNDS BY FERRIC REDUCING ACTIVITY
S. no. | Compound | Ferric reducing activity (100µg/mL) % |
1 | III a | 0.38 |
2 | III b | 0.46 |
3 | III c | 0.34 |
4 | III d | 0.44 |
5 | III e | 0.40 |
6 | III f | 0.42 |
7 | Ascorbic acid | 0.0865 |
DISCUSSION: A novel series of 2-hydroxy quinoline derivatives III (a-f) have been synthesized by reacting 7 or 8-substituted -2-hydroxy-3-formylquinolines I (a, b) with substituted hydrazides. The purity of the synthesized compounds was confirmed by TLC. The structure of all the newly synthesized compounds was confirmed by physicochemical and spectral data.
All the compounds were screened for their in–vitro antioxidant activities using free radical scavenging activity by DPPH assays method and ferric ion reduction method using ascorbic acid as the standard drug. Compounds III b, III d, and III f showed significant antioxidant activity.
CONCLUSION: In series III (a-f) it is evidently observed that the antioxidant activity of the compounds has been greatly influenced by the presence of methyl as a substituent on the quinoline nucleus. Quinoline moiety and its Schiff bases do contribute for the observed activity but the presence of methyl at 7th/8th position of quinoline contributed to its significant antioxidant activity. The preliminary antioxidant activity screening result of these compounds depicted them as potential antioxidant leads endowed with moderate to excellent activity. Further enhancement in the activity can be achieved by slight modifications in the ring substituent.
ACKNOWLEDGEMENT: The authors are thankful to The Principal KLE College of Pharmacy, Hubli, for providing the necessary facilities to carry out this research work. We also thank The Director, SAIF, Punjab University, Chandigarh, Punjab, India, and The Director, USIC, Karnataka University, Dharwad, India, for providing spectral data.
CONFLICTS OF INTEREST: No conflict of interest.
REFERENCES:
- Slusarczyk S, Hajnos M, Skalicka-Woźniak K, Matkowski A: Antioxidant activity of polyphenols from Lycopus lucidus Food Chemistry 2009; 113: 134-38.
- Dakubo GD: Mitochondrial Genetics and Cancer; Springer-Verlag Berlin Heidelberg: Berlin, Germany, 2010; doi: 10.1007/978-3-642-11416-8.
- Torreggiani A and Tamba M: Free radical scavenging and metal chelating activity of some therapeutic heterocyclic agents. Trends in Heterocyclic Chemistry 2005; 10: 115-37.
- Karalı N, Güzel O, Ozsoy N, Ozbey S and Salman A: Synthesis of new spiroindolinones incorporating a benzothiazole moiety as antioxidant agents. European Journal of Medicinal Chemistry 2010; 45: 1068-77.
- Patil VP, Markad VL, Kodam, KM and Waghmode SB: Facile preparation of tetrahydro-5H-pyrido[1,2,3]-1,4-benzoxazines via reductive cyclization of 2-(8-quinolinyloxy) ethanones and their antioxidant activity. Bioorganic and Medicinal Chemistry Letters 2013; 23: 6259-63.
- Azam F: Therapeutic potential of free radical scavengers in neurological disorders in handbook of free radicals: formation, types and effects; Chapter 2; Kozyrev D, Slutsky V, Eds; Nova Science Pub. Inc.: Hauppauge, NY, USA, 2010, 57-97.
- Nikookar H, Mohammadi-Khanaposhtani M, Imanparast S, Faramarzi MA, Ranjbar PR, Mahdavi M and Larijani B: Design, synthesis and in vitro α-glucosidase inhibition of novel dihydropyrano [3,2-c] quinoline derivatives as potential anti-diabetic agents. Bioorganic Chemistry 2018; 77: 280-286.
- Wadhwa P, Jain P, Jadhav H and Rudrawar S: Quinoline, coumarin and other heterocyclic analogues based HIV-1 integrase inhibitors. Current Drug Discoveries Technology 2018; 15(1): 2-19.
- Joao PSF, Susana MC, Filipe AAP, Artur MSS and Ver LMS: Synthesis of 2-aroylfuro [3,2-c] quinolones from quinolone-based chalcones and evaluation of their antioxidant and anticholinesterase activities. New Journal of Chemistry 2020; 44: 6501-09.
- Chih-Hua T, Chun-Wei T, Shin-I P, Yeh-Long C, Cherng-Chyi T and Chih-Mei C: Discovery of Pyrazolo[4,3-c]quinolines Derivatives as Potential Anti-Inflammatory Agents through Inhibiting of NO Production. Molecules 2018; 23: 1036
- Kumar S, Goel N, Afzal O, Ali MR and Bawa S: In-vitro antibacterial/ antifungal screening of 2- chloroquinoline scaffold derivatives. Journal of Antibiotics Research 2015; 1(1): 1-11.
- Senerovic L, Opsenica D, Moric I, Aleksic I, Spasić M and Vasiljevic B: Quinolines and quinolones as antibacterial, antifungal, anti-virulence, antiviral and anti-parasitic agents. Advances in Experimental Medicine and Biology 2019; 1282: 37-69.
- Thakare PP, Shinde AD, Chavan AP, Nyayanit NV, Bobade VD and Mhaske PC: Synthesis and biological evaluation of new 1,2,3‐triazolyl‐pyrazolyl‐quinoline derivatives as potential antimicrobial agents. Chemistry Select 2020; 5(15): 4722-27.
- Nithyanantham M, Ramaiah S, Navaneetharaman A, Vedachalam G and Joseph TL: Synthesis, anticonvulsant and antihypertensive activities of 8-substituted quinoline derivatives. Biological and Pharmaceutical Bulletin 2004; 27(10): 1683-87.
- Atef MA, Ali D, Wafaa El-E, Sally AElA and Sebaey M: Synthesis, characterization and evaluation of anti-inflammatory and analgesic activity of some novel quinoline based thiazolidinone heterocycles. Egyptian Journal of Chemistry 2018; 67-77.
- Goyal S, Binnington B, McCarthy SDS, Desmaele D, Ferrie L and Figadere B: Inhibition of in-vitro Ebola infection by anti-parasitic quinoline derivatives [version 1; peer review: 2 approved] F1000Research 2020; 9: 268.
- Shruthi TG, Sangeetha S and Sumesh E: Design, synthesis and study of antibacterial and antitubercular activity of quinoline hydrazone hybrids. Heterocyclic Communications 2020, 26(1): 137-47.
- Kumar MRP, Joshi SD, Dixit SR and Kulkarni VH: Synthesis, antibacterial and antitubercular activities of some novel quinoline derivatives. Indian Journal of Heterocyclic Chemistry 2014; 23: 353-58.
- Zahid Z, Sameer IS, Santosh NM and Deepak KL: Synthesis, biological evaluation and computational study of new quinoline hybrids as antitubercular agent. Letters in Drug Design & Discovery 2018; 15(9): 914.
- De la Guardia C, Stephens DE, Dang HT, Quijada M, Larionov OV and Lleonart R: Antiviral activity of novel quinoline derivatives against dengue virus serotype 2. Molecules 2018; 23(3): 672.
- Guo LJ, Wei CX, Jia JH, Zhao LM and Quan ZS: Design and synthesis of 5-alkoxy-[1,2,4] triazolo[4,3-a]quinoline derivatives with anticonvulsant activity. Eur J Med Chem 2009; 44: 954-58.
- Matada BS, Pattanashettar R and Yernale NG: A comprehensive review on the biological interest of quinoline and its derivatives. Bioorganic & Medicinal Chemistry 2021; 32: 115973.
- Bhaskaran S, Yohannan SM, Chacko YP, Somasekharan S, Stevan A, Sanja JA, Christian VA and Badiadka N: Quinoline derivatives as possible lead compounds for anti-malarial drugs: Spectroscopic, DFT and MD study. Arabian Journal of Chemistry 2020; 13 (1): 632-48.
- Selim MR, Zahran MA, Belal A, Abusaif MS, Shedid SA, Mehany ABM, Elhagali GAM and Ammar YA: Hybridized quinoline derivatives as anticancer agents: design, synthesis, biological evaluation and molecular docking. Anticancer Agents Medicinal Chemistry 2019; 19(4): 439-52.
- Jia L, Bian M, Guo-Hua G, Di W, Gui-Lan B and Li-Jun Y: Current research on anti-breast cancer synthetic compounds. Royal Society of Chemistry Advance 2018; 8: 4386-4416.
- Mohammed AMM, Magda AEl-Sayed, Waleed AB and Basem M: Cytotoxicity and molecular targeting study of novel 2-chloro-3- substituted quinoline derivatives as antitumor agents. Letters in Drug Design & Discovery 2019; 16(3): 273.
- Habbu PV, Pradeep Kumar MR, Mahadevan KM, Joshi SD, Rashmi NV, Kulkarni VH: Synthesis and screening of some novel 2-methyl-4-amino-tetrahydroquinoline derivatives for their hepatoprotective and anticonvulsant activity in rodents. Indian Journal of Heterocyclic Chemistry 2013; 23: 87-96.
- Kumar MRP and Hunashal RD: Synthesis, spectral characterization and in-vitro screening of some novel tetrahydroquinoline derivatives for their antitubercular, antioxidant activities. Saudi Journal of Medical and Pharmaceutical Science 2018; 4(1B): 151-55.
- Kumar MRP and Hunashal RD: Synthesis and in-vitro screening of some novel 6-substituted/ unsubstituted-2-phenyl-1,2,3,4-tetrahydro quinoline derivatives as potential antitubercular and antioxidant agents. European Journal of Biomedical & Pharmaceutical Science 2018; 5(3): 240-44.
- Braca A, Sortino C and Politi M: Anti-oxidant activity of flavonoids from Licania licaniae flora. Journal of Ethnopharmacology 2002; 79: 379-81.
- Szydlowska-Czerniak A, Dianoczki C, Recseg K, Karlovits G and Szlyk E: Determination of antioxidant capacities of vegetable oils by ferric-ion spectrophoto-metric methods. Talanta, 2008; 76: 899-905.
How to cite this article:
Kumar MRP and Hunashal RD: Synthesis, spectral characterization and in-vitro antioxidant activity screening of some novel 2-hydroxy quinoline derivatives. Int J Pharm Sci & Res 2021; 12(12): 6567-72. doi: 10.13040/IJPSR.0975-8232.12(12).6567-72.
All © 2021 are reserved by the International Journal of Pharmaceutical Sciences and Research. This Journal licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Article Information
43
6567-6572
484 KB
307
English
IJPSR
Pradeep Kumar M. R. * and Hunashal R. D.
Department of Pharmaceutical Chemistry, KLE College of Pharmacy, A Constituent Unit of KLE Academy of Higher Education and Research [KAHER], Hubli, Karnataka, India.
pradeepmrpk@yahoo.co.in
03 January 2021
03 May 2021
28 May 2021
10.13040/IJPSR.0975-8232.12(12).6567-72
01 December 2021