Synthesis, Characterization and Biological Evaluation of some new Isoxazole and Pyrazole compounds for Anti-obesity drug

 

Bhagyashree Agrawal*, Bhaskar Kumar Gupta, Satish Kumar Sahu

Department of Pharmaceutical Chemistry, School of Pharmacy, CEC, Bilaspur, 495004, Chhattisgarh India.

Institute of Pharmaceutical Sciences and Research, People’s University,

Bhopal, 462037, Madhya Pradesh, India.

 

ABSTRACT:

The discipline of medicinal chemistry is dedicated to the discovery and development of new agents for treating diseases. Most of this activity directed to new natural or synthetic organic compounds. Development of organic compounds has grown beyond traditional synthetic methods. It now includes the new exciting new field of biotechnology using cells biochemistry to synthesize new compounds. Chemical synthesis is purposeful execution of chemical reactions to get a product or several products. Chemical synthesis is purposeful execution of chemical reactions to get a product or several products. The requirement is to synthesize novel molecules having good potential with high therapeutic index. Keeping in view the diverse therapeutic activities of Chalcones for the preparation of bioactive heterocycles, it was contemplated to synthesize a novel series of Chalcones. Attention has been focused on the substitution of acetophenone and benzaldehydes to achieve new anti-obesity profiles.

 

 

 

INTRODUCTION: 

Chalcones or 1,3-diaryl-2-propen-1-ones, belong to the flavonoid family. Chemically they consist of open-chain flavonoids in which the two aromatic rings are joined by a three-carbon α, β-unsaturated carbonyl system. Chalcones are abundant in edible plants and are considered to be precursors of flavonoids and iso-flavonoids. A vast number of naturally occurring chalcones are polyhydroxylated in the aryl rings. The radical quenching properties of the phenolic groups present in many Chalcones have raised interest in using the compounds or Chalcone rich plant extracts as drugs or food preservatives^1-3. Obesity and Diabetes are major threat to public health, despite tremendous progress in medicinal chemistry. The impact is more acute in developing countries due to nonavailability of desired medicines. 

 

Obesity is a serious health threatening factor in an urbanized society, which increases the risk of other diseases, such as type 2 diabetes, cardiovascular disease, hypertension etc. high energy intake and low energy expenditure, accompanied by changing lifestyles, have increased the prevalence of obesity and this increase is expected to continue. Orlistat and Sibutramine have been accepted in us for long term use and Diethylpropion, phendimetrazine and phentermine for short term use.

 

Figure 1: Structure of Chalcone

 

Depending on the substitution of the two aromatic rings the Chalcones can display different spectra of activity. For instance, (E)-Chalcones containing 4-alkylthio- or 4-alkoxy side chains and 4’-N-piperidine or 4’-N-methylpiperidine groups, as para substituents, exhibited a narrow spectrum of antibacterial activity, being affective against Gram-positive bacteria⁴.

 

The compounds with the backbone of Chalcones have been reported to possess various biological activities such as antimicrobial, anti-inflammatory, antiplatelet, antimalarial, antiviral, antileishmanial, anticancer, antioxidant, antitubercular, antihyperglycemic, inhibition of leukotriene B4, inhibition of tyrosinase and inhibition of aldose reductase activities^5-8. The presence of a reactive unsaturated ketone function in Chalcone is found to be responsible for their antimicrobial activity^9-10.

 

Obesity is a serious health threatening factor in an urbanized society, which increases the risk of other diseases, such as type 2 diabetes, cardiovascular diseases, hypertensions etc. The requirement is to synthesize novel molecules having good potential with high therapeutic index. Keeping in view the diverse therapeutic activities of Chalcones for the preparation of bioactive heterocycles, it was contemplated to synthesize a novel series of Chalcones^11-14. Attention has been focused on the substitution of acetophenone and benzaldehydes to achieve new anti-obesity profiles.

 

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Body mass index (BMI), a measurement which compares weight and height, defines people as overweight (pre-obese) if their BMI is between 25 and 30kg/m²and obese when it is greater than 30kg/m². Obesity is most commonly caused by a combination of excessive food energy intake, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes endocrine disorders, medications or psychiatric illness. Only one anti-obesity medication Orlistat (Xenical) is currently approved by the FDA for long termuse. It reduces intestinal fat absorption by inhibiting pancreatic lipase.  Rimonabant (Acomplia), a second drug works via a specific blockade of the endocannabinoid system. It has been developed from the knowledge that cannabis smokers often experience hunger, which is often referred to as "the munchies". It had been approved in Europe for the treatment of obesity but has not received approval in the United States or Canada due to safety concerns¹⁵. The European Medicines Agency in October 2008 recommended the suspension of the sale of Rimonabant as the risks seem to be greater than the benefits. Sibutramine (Meridia), which acts in the brain to inhibit deactivation of the neurotransmitters, thereby decreasing appetite was withdrawn from the United States and Canadian markets in October 2010 due to cardiovascular concerns¹⁶. Anti-obesity drugs operate through one or more of the following mechanisms¹⁷:

·       Suppression of the appetite. Catecholamines and their derivatives (such as phentermine and other amphetamine-based drugs) are the main tools used for this, although other classes of drugs such as anti-depressants and mood stabilizers have been anecdotally used for appetite suppression (bupropion and topiramate). Drugs blocking the cannabinoid receptors may be a future strategy for appetite suppression.

·       Increase of the body's metabolism.

·       Interference with the body's ability to absorb specific nutrients in food. For example, Orlistat (also known as Xenical) blocks fat breakdown and thereby prevents fat absorption. The OTC fiber supplements glucomannan and guar gum have been used for the purpose of inhibiting digestion and lowering caloric absorption.

 

MATERIALS AND METHODS:

Materials:

All the chemicals are of analytical grade and laboratory grade as needed and are provided by institution authorities. The instruments and animals required are also provided by institution authorities.

 

Methods:

Synthesis of proposed derivatives:

Sodium hydroxide (30%) was dissolved in distilled water, rectified spirit (0.007 M) was added to 500 ml capacity bolt head flask provided with mechanical stirrer. The flask was immersed in bath of crushed ice to obtain 20±2ºC temperature. Substituted acetophenones (0.007 M) (3-hydroxyacetophenone,2-hydroxyacetophenone and 4-hydroxyacetophenone) was dissolved in the above mixture with stirring followed by addition of substituted benzaldehydes (0.007M)(4-methoxybenzaldehyde,3,4-dimethoxybenzaldehyde-3,4methelyenedioxybenzaldehyde). The temperature of the mixture was maintained at about 20ºC (the limits are 15-30ºC) and the reaction mixture was stirred at 500 rpm for 6hrs. Rection mixture was kept at 8ºC overnight. The product was filtered using Buchner funnel, washed with cold water and dried in air. Recrystallisation was done using Ethanol. The completion of reaction was monitored by TLC. The proposed scheme for synthesis is as follows:

 

Figure 2: Scheme for the Synthesis of Proposed Pyrazole and Isoxazole Derivatives

 

Synthesis of Substituted Isoxazole derivatives: (4IA-4IE)¹⁸

Addition and cyclization:

A mixture of substituted Chalcones (1.0mol) (3A-3E) respectively and hydroxylamine hydrochloride (1.0mol) with sodium acetate in ethanol (25ml) was taken in a round bottom flask. The reaction mixture was refluxed for 7 hrs. on a water bath followed with addition of ice-cold water at room temperature. The mixture was kept overnight at 8⁰C. The precipitates were filtered, washed with distilled water and dried. The product was recrystallized with ethanol to get the final product. The completion of reaction was monitored by TLC.

 

Synthesis of Substituted Pyrazole derivatives: (4II A-4II E)^19-20

Addition and cyclization:

A mixture of substituted Chalcones (1.0mol) (3A-3E) respectively and hydrazine hydrate (1.0mol) with sodium acetate in ethanol (25ml) was taken in a round bottom flask. The reaction mixture was refluxed for 8 hrs. on a water bath followed with addition of ice-cold water at room temperature. The mixture was kept overnight at 8⁰C. The precipitates were filtered, washed with distilled water and dried. The product was recrystallized with ethanol to get the final product. The completion of reaction was monitored by TLC.

 

Table 1: Proposed structures of synthesized compounds

Comp Code	Proposed Structure	IUPAC Names
4I A		4-(3-(4-methoxyphenyl)isoxazol-5-yl)phenol
4I B		3-(3-(4-methoxyphenyl)isoxazol-5-yl)phenol
4I C		2-(3-(4-methoxyphenyl)isoxazol-   5-yl)phenol
4I D		4-(3-(3,4-dimethoxyphenyl)isoxazol-5-yl)phenol
4I E		4-(3-(benzo[d][1,3]dioxol-5-yl)isoxazol-5-yl)phenol
4II A		4-(3-(4-methoxyphenyl)-1H-pyrazol-5-yl)phenol
4II B		3-(3-(4-methoxyphenyl)-1H-pyrazol-5-yl)phenol
4II C		2-(3-(4-methoxyphenyl)-1H-pyrazol-5-yl)phenol
4II D		4-(3-(3,4-dimethoxyphenyl)-1H-pyrazol-5-yl)phenol
4II E		4-(3-(benzo[d][1,3]dioxol-5-yl)-1H-pyrazol-5-yl)phenol

 

Physicochemical characterization of synthesized compounds:

Melting point:

Melting points were determined by open capillary tube. Melting Point Apparatus (Programmable Melting Point Apparatus Model; 10MPA12, Make; DBK Instruments, India) with a thermometer fitted at its one point and samples in the other point. The temperature, at which the partly melted substance was observed in the capillary tube, considered the melting range of synthesized compound.

 

Structure elucidation of the synthesized conjugates:

a)   Fourier Transform Infrared spectrum (FTIR):FT-IR spectra were recorded on MB 3000 (Make; ABB Bomem, Canada) spectrometer.

b)   Nuclear magnetic resonance studies: ¹H NMR spectra were recorded on Avance II 400 (Make; Bruker, France) NMR Spectrometer.

c)   Mass Spectral Studies: Mass spectra were recorded on Jeol SX-102 (Make; Waters, Massachusetts) spectrometer.

 

In-Vivo Activity of synthesized compound:

In-vivo antiobesity activity:

In-vivoantiobesity activity of synthesized compounds was determined by High fat diet induced obesity model. Female wistar rats (150±30g) were given high fat diet (Protein-14.7%, Carbohydrates-44.2%, Lipid-15.8%, Fiber-2.5%, Vit.mixture-1.2%, Water-19%) for 20 days. Animals were divided into thirteen groups, each comprising of three rats, including a control and standard group. Saline of 0.9% conc. was given to the animals of control group. Sibutramine (5mg/kg/p.o) was given as standard drug with 0.9% saline and high fat diet. The synthesized compounds (dose of each compound was calculated to equivalent to 100 mg/kg body weight p.o) was administered in suspended in 0.9% saline. The body weight (gm) was recorded on day one and then on alternate days for 20 days using digital weighing balance.

 

Table 2. Groups for preclinical study

Group no.	Type	Treatment
1	Standard	Sibutramine+ High Fat Diet
2	Control	Saline Solution
3	Diet Control	High Fat Diet
4-13	Test	Synthesized compounds + High Fat Diet

 

RESULT:

Substituted Chalcone derivatives were synthesized, 5 such compounds were synthesized. Substituted Isoxazole and Pyrazole derivatives were synthesized using substituted acetophenone and substituted benzaldehydes via cyclization of synthesized chalcones.10 such compounds were synthesized.

 

Physico-chemical parameters were determined experimentally obtained by Melting range, % Yield. R_f value of the compounds was determined by TLC usingsilica gel-G. Themaximum R_fvalue, wasobtainedin Chloroform: Methanol: Benzene in the ratio of 2:3:5 and theminimum R_fvalue, wasobtainedin Chloroform: Ethylacetate in the ratio of 2:3. (shown in Table 3).

 

Table 3. Physico-chemical data of synthesized compounds

Compound Code	% Yield	Melting Point (oC)	Rf value
4I A	51%	90-95	0.79
4I B	55%	95-100	0.66
4I C	57%	96-101	0.68
4I D	60%	100-105	0.71
4I E	57%	101-106	0.81
4II A	58%	170-175	0.73
4II B	55%	160-165	0.47
4II C	56%	161-166	0.66
4II D	55%	180-185	0.88
4II E	51%	166-171	0.78

 

Structures of all the synthesized compounds have been established on the basis of their consistent IR (in table 4), ¹H-NMR (in table 6) and Mass spectral analysis (in table 5).

 

Table 4: Infrared spectral characterization of the synthesized derivatives

Compound code	Characteristic peaks of IR spectra
4IA	3232 (O-H str.), 3225 (C-H str. aliphatic), 1609 (C=O str.), 1520 (C=N str. aromatic), 1483 (C=C str. aromatic), 1319 (C-O-N str. aromatic), 810 (C-Hdef. aromatic)
4IB	3082(O-H str.),3225 (C-H str.aliphatic),1609 (C=O str.),1520 (C=N str. aromatic),1483 (C=C str. aromatic),1319 (C-O-N str. aromatic),810 (C-H def. aromatic)
4IC	C 3082(O-H str.),3225 (C-H str.aliphatic),1609 (C=O str.),1520 (C=N str, aromatic),1483(C=C str. aromatic),1319 (C-O-N str. aromatic),810 (C-H def. aromatic)
4ID	2920 (O-H str.),1682 (aromatic C=C str.),1612 (aromatic C=N str.),1599 (C=O str.), 1348 (C-O-N str. aromatic),866 (C-H def. aromatic),1058 (C-O-C str. asymmetric),746 (C-H bend asymmetric)
4IE	2920 (O-H str.),1682 (aromatic C=C str.),1612 (C=N str. aromatic),1599 (C=O str.),1348 (C-O-N str. aromatic),866 (C-H def. aromatic),1148 (C-O-C str. asymmetric),765 (C-H bend asymmetric)
4IIA	3246 (O-H str.),3236 (aromatic N-H str.), 3229 (C-H str.),3022 (C-H str. aliphatic),1522 (C=C str.),1420 (aromatic C=N str.),820 (C-H bend)
4IIB	3246 (O-H str.), 3236 (aromatic N-H str.), 3229 (C-H str.), 3025 (C-H str. aliphatic), 1690 (C=C str.), 1425 (aromatic C=N str.), 901 (C-H bend)
4IIC	3246 (O-H str.), 3236 (aromatic N-H str.), 3229 (C-H str.), 3025 (C-H str. aliphatic), 1416 (aromatic C=N str.), 1352 (C=C str.), 910 (C-H bend)
4IID	3082 (O-H str.), 3232 (C-H str.), 1609 (N-H bend), 1520 (C=C str.), 1120 (C-O-C str. asymmetric), 876 (C-H bend)
4IIE	3082 (O-H str.), 3225 (C-H str.), 1609 (N-H bend), 1520 (C=C str.), 1495 (C-O-C str. asymmetric), 947 (C-H bend)

 

Table 5: Mass spectral characterization of the synthesized derivatives

Table 6: ¹H NMR spectral characterization of the synthesized derivatives

Compound Code	1H NMR (δ, ppm)
4IA	8.51-7.61 (r, 4H, aromatic ring), 6.83-7.53 (m, 6CH, aromatic ring), 5.0 (d, COH in ring), 5.4 (m,1H, CH), 2.87-3.73 (s, OCH3)
4IB	8.51-7.61 (r, 4H, aromatic ring), 6.95-7.37 (m, 6CH, aromatic ring), 5.0 (d, COH in ring), 5.3 (m,1H, CH), 2.87-3.73 (s, OCH3)
4IC	8.51-7.61 (r, 4H, aromatic ring), 6.88-7.37 (m, 6CH, aromatic ring), 5.0 (d, COH in ring), 5.3 (m,1H, CH), 2.18-3.73 (s, OCH3)
4ID	8.51-7.61 (r, 4H, aromatic ring), 6.93-7.31 (m, 6CH, aromatic ring), 5.0 (d, COH in ring), 5.3 (m,1H, CH), 2.18-3.73 (s,2 OCH3)
4IE	8.51-7.61 (r, 4H, aromatic ring), 6.7-7.31 (m, 6CH, aromatic ring), 5.0 (d, COH in ring), 5.3 (m,1H, CH), 5.9 (d, CH2)
4IIA	6.7-7.37 (m, 4CH, aromatic ring), 7.5 (r, 4H, aromatic ring), 5.0 (d, COH in ring), 2.87-3.7 (s, OCH3), 13.7 (r, NH)
4IIB	6.8-7.37 (m, 4CH, aromatic ring), 7.5 (r, 4H, aromatic ring), 5.0 (d, COH in ring), 2.87-3.7 (s, OCH3), 13.7 (r, NH)
4IIC	6.79-7.37 (m, 4CH, aromatic ring), 7.5 (r, 4H, aromatic ring), 5.0 (d, COH in ring), 2.87-3.7 (s, OCH3), 13.7 (r, NH)
4IID	6.79-7.31 (m, 4CH, aromatic ring), 7.6 (r, 4H, aromatic ring), 5.0 (d, COH in ring), 2.87-3.7 (s, 2OCH3), 13.7 (r, NH)
4IIE	6.79-7.31 (m, 4CH, aromatic ring), 7.6 (r, 4H, aromatic ring), 5.0 (d, COH in ring), 5.9 (d,CH2 in ring), 13.7 (r, NH)

 

Compound 4II E have shown good anti-obesity activity against Diet induced Obesity Model (gain in body weight were found to be 6.55±1.138 gm) which is the minimum weight gain in experiment. Sibutramine (standard drug) have shown the significant weight gain results. Compounds 4I A,4I C ,4II A,4II B,4II C have shown the moderate gain of body weight and are considered as less significant compounds as shown (in table 7).

 

 

Table 7: Result of In-vivo Anti-obesity activity

S. No.	Groups	Weight on day 1(gm)	Weight on day 20(gm)	Weight gain (gm)
1.	4I A	161.24±3.185	170.24±2.027	9.0±1.158
2.	4I B	157.58±3.296	167.58±2.138	10.0±1.267
3.	4I C	159.11±3.317	168.61±2.249	9.50±1.068
4.	4I D	162.18±3.428	169.68±2.350	7.5±1.078
5.	4I E	161.93±3.519	169.28±2.461	7.35±1.168
6.	4II A	155.91±3.601	164.91±2.572	9.0±1.029
7.	4II B	158.71±3.711	168.24±2.683	9.53±1.208
8.	4II C	164.83±3.821	174.53±2.794	9.7±1.307
9.	4II D	166.58±3.918	174.08±2.813	7.5±1.105
10.	4II E*	157.88±3.056	164.38±2.918	6.55±1.138
11.	Sibutramine (Standard)	163.24±3.489	171.56±4.360	8.32±1.129
12.	Diet Control	160.33±3.094	185.83±4.524	25.50±1.429
13.	Control	156.12±3.562	158.23±4.154	2.11±1.407

Data presented as Mean±SEM , n=3, p<0.05   * Indicate most potent compound

 

DISCUSSION:

Substituted Isoxazoles and Pyrazoles were synthesized from substituted Chalcones. Overall, 10 such compoundswere synthesized.  Melting range of the compounds were determined by open capillary tube method. Mostofthecompoundswereobtained in yieldsofabove 50%. The compounds were eluteda long with the solvent system to a distanceof more than 0.60cm. Structures of all the synthesized compounds have been established on the basis of their consistent IR, ¹H-NMR and Mass spectral analysis.

 

Figure 3: FT-IR/¹H-NMR/Mass spectra of most potent compound

 

CONCLUSION:

Some Chalcone derivatives were synthesized and further substituted Isoxazole and Pyrazole derivatives were synthesized and structure of all the synthesized compounds have been established on the basis of their consistent IR, ¹H-NMR and Mass spectral data. In accordance with the data obtained from in-vivo activity, it was concluded that all the synthesized compounds have shown moderate activity.The results of present study have suggested that the Isoxazole and Pyrazole derivatives have excellent scope for further development as commercial anti-obesity agents.

 

CONFLICT OF INTEREST:

The authors have no conflicts of interest regarding this investigation.

 

ACKNOWLEDGMENTS:

The authors would like to thank College of Pharmacy IPS Academy Indore (M.P.) for successful conduction of the work.

 

REFERENCES:

1.      Nowakowska. Z. A review of anti-infective and anti-inflammatory chalcones. European Journal of Medicinal Chemistry.  2007; 42: 125–137.

2.      Vibhute YB.Nalwar YS.Khansole SV.Vibhute AY. Sayyed MA.Mokle SS. et al. Synthesis of some new bioactive Chalcone and Flavone. Research Journal of Pharmacy and Technology. 2009; 2(4): 846-849.   

3.      Kumar P. Kumar A.Fernendes J. et al.Synthesis and Biological Activity of Some Novel Quinolinyl Chalcones Derived from N-Substituted 2-Quinolones. Research Journal of Pharmacy and Technology. 2013; 6(12): 1336-1339.

4.      Avila HP. Smania EFA. and Monache FD. et al. Structure–activity relationship of antibacterial chalcones. Bioorganic & Medicinal Chemistry. 2008; 16: 9790–9794.

5.      Bhat IK, Kumar A.Kumar P.Riyaz EK et al. Synthesis and Biological Evaluation of Some Novel Pyrimidine Derivatives Derived from Chalcones. Research Journal of Pharmacy and Technology. 2014; 7(9): 995-998.  

6.      Lunkad AS, Kothawade SN, Jadhav DV. Chaudhari PS., Bornare SP. Et al. Synthesis and Antimicrobial Activity of Some New Chalcones Containing Benzofuran and Benzofuran Schiff Bases. Research Journal of Pharmacy and Technology.  2015; 8(3): 276-279.

7.      Kumar A. Shetty P. Amrutha CL. et al. Synthesis and Antimicrobial Evaluation of Some Novel Derivatives of Coumarin Moiety. Research Journal of Pharmacy and Technology. 2016; 9(5): 545-548.

8.      Kumar A. Fernandes J. Kumar P. et al. Synthesis and Biological Evaluation of Some Novel Pyrazoline incorporated 2-Quinolones. Research Journal of Pharmacy and Technology. 2016; 9(12):2257-2260.

9.      Jin C. Liang Y.He H and Fu L.et al. Synthesis and antitumor activity of novel chalcone derivatives. Biomedicine & Pharmacotherapy. 2011; 10: 1–3.

10.   Yesuthangam Y.Pandain S.Venkatesan K.Gandhidasan R. Murugesan R. et al.The photogeneration of reactive oxygen species and photo induced plasmid DNA cleavage by novel synthetic chalcones. Journal of Photochemistry. 2011; 3(1): 1–9.

11.   Kumar P,Kumar, A.,Pinto J.S.,Synthesis and Biological Evaluation of Pyrimidine Derivatives Via Pyrrolyl Chalcones. Research Journal of Pharmacy and Technology. 2017; 10(5): 1392-1394.

12.   Kumar P., Kumar A., D’Souza S., Synthesis and Antimicrobial Evaluation of Different Substituted Phenylpropenone Pyrrolyl Chalcones. Research Journal of Pharmacy and Technology. 2017; 10(5): 1426-1428.

13.   Revanasiddappa B.C., Kumar M.V., Nayak P., Ali A., Jisha M. Synthesis, Antibacterial and Antifungal Evaluation of Novel Pyrazoline Derivatives.  Research Journal of Pharmacy and Technology. 2017; 10(5): 1481-1484.

14.   Singh K., Kumari S., Gupta Y.K. Synthesis and Antimicrobial Activity of New Pyrazoles and Chalcones Derived from Cyclic Imides. Research Journal of Pharmacy and Technology. 2017; 10(12): 4483-4488.

15.   Kalirajan R., Sivakumar S.U., Jubie S., Gowramma B. and Suresh B. Synthesis and Biological evaluation of some heterocyclic derivatives of Chalcones. International Journal of ChemTech Research.  2009; 1(1): 27-34.

16.   Tuskaev V.A., Oganesyan E.T. and Mutsueva S.K., Synthesis of 1-phenyl-3-(chromon-3-yl)-2-propen-1-one derivatives: a new group of biologically active compounds. European Journal of Medicinal Chemistry. 2002; 36(2):27–29.

17.   Tripathi K.D., Essential of Medical Pharmacology. Jaypee Brothers. 5, 2003, 254–273.

18.   Satyanarayana M., Tiwari P., Tripathi B.K., Srivastava A.K. and Pratap R. Synthesis and antihyperglycemic activity of chalcone based aryloxypropanolamines. Bioorganic & Medicinal Chemistry. 2004; 12: 883–889.

19.   Rojas J., Domınguez J.N., CharrisJ.E.,LoboG.,Paya M. and Ferrandiz. Synthesis and inhibitory activity of dimethylamino-chalcone derivatives on the induction of nitric oxide synthase. European Journal of Medicinal Chemistry. 2002; 37: 699–705.

20.   Prasad Y.R., Rao A.L. and Rambabu R., Synthesis and Antimicrobial Activity of some Chalcone Derivatives. European Journal of Chemistry. 2008; 5(3): 461-466.

 

 

Accepted on 16.12.2022           © RJPT All right reserved

Research J. Pharm. and Tech 2023; 16(8):3837-3842.