Synthesis and Antioxidant Activity of Polyhydroxylated trans-Restricted 2-Arylcinnamic Acids
Abstract
:1. Introduction
2. Results and Discussion
2.1. Chemistry
Comp. | R1 | R2 | R3 | R4 | R5 | R6 | Total OH | Type of Phenolic Fragments in Rings A/B | Antioxidant Activity a | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|
DPPH● | O2●▬ (µM) | HO● (µM) | ||||||||||
EC50 (µM) | TEC50 b (min) | |||||||||||
3a | H | H | H | H | H | H | 0 | –/– | na c | nd c | na | 201.0 ± 8.0 |
3b | H | H | H | H | H | OH | 1 | –/phenol | na | nd | na | 133.7 ± 16.1 |
3c | H | H | H | OH | H | H | 1 | –/phenol | na | nd | na | 134.2 ± 5.6 |
3d | H | H | H | OH | H | OH | 2 | –/resorcinol | 41.30 ± 0.35 | 32.25 ± 2 | na | 120.9 ± 9.8 |
3e | H | H | OH | H | H | OH | 2 | –/hydroQ c | 6.74 ± 0.30 | 3.5 ± 0.1 | na | 122.9 ± 2.0 |
3f | H | H | H | H | OH | OH | 2 | –/catechol | 6.26 ± 0.58 | 4 ± 0.1 | 372.9 ± 8.5 | 108.9 ± 14.0 |
3g | H | H | H | OH | OH | H | 2 | –/catechol | 5.81 ± 0.29 | 2.75 ± 0.1 | 109.7 ± 5.3 | 59.4 ± 0.4 |
3h | H | H | OH | OH | OH | H | 3 | –/pyrogallol | 4.47 ± 0.07 | 3 ± 0.1 | 11.1 ± 0.1 | 100.6 ± 2.1 |
3i | OH | OH | H | H | H | H | 2 | catechol/– | 7.62 ± 0.28 | 31.75 ± 1.5 | 233.6 ± 0.9 | 118.7 ± 2.6 |
3j | OH | OH | H | H | H | OH | 3 | catechol/phenol | 8.04 ± 0.32 | 26 ± 0.75 | 238.0 ± 5.4 | 79.1 ± 0.6 |
3k | OH | OH | H | OH | H | H | 3 | catechol/phenol | 7.34 ± 0.25 | 33 ± 2 | 230.7 ± 4.9 | 64.5 ± 0.8 |
3l | OH | OH | H | OH | H | OH | 4 | catechol/resorcinol | 5.43 ± 0.36 | 26.5 ± 0.75 | 269.2 ± 12.8 | 68.9 ± 0.8 |
3m | OH | OH | OH | H | H | OH | 4 | catechol/hydroQ c | 3.33 ± 0.04 | 10 ± 0.5 | nd | 58.8 ± 1.1 |
3n | OH | OH | H | H | OH | OH | 4 | catechol/catechol | 3.52 ± 0.05 | 13 ± 0.5 | 137.2 ± 3.9 | 84.6 ± 2.3 |
3o | OH | OH | H | OH | OH | H | 4 | catechol/catechol | 2.76 ± 0.12 | 6.5 ± 0.25 | 64.9 ± 1.9 | 42.6 ± 1.8 |
3p | OH | OH | OH | OH | OH | H | 5 | catechol/pyrogallol | 2.09 ± 0.11 | 9 ± 0.75 | 11.3 ± 0.5 | 58.6 ± 0.9 |
Trolox | – | – | – | – | – | – | 1 | phenol | 9.34 ± 0.07 | 5.75 ± 0.25 | na | 109.6 ± 7.8 |
CA | – | – | H | OH | OH | H | 2 | catechol | 9.48 ± 0.17 | 9 ± 0.75 | 126 ± 10.6 | 73.0 ± 1.8 |
PCA | OH | OH | – | – | – | – | 2 | catechol | 8.85 ± 0.24 | 28.25 ± 1.25 | 233.5 ± 3.0 | 117.7 ± 1.8 |
GA | – | – | – | – | – | – | 3 | pyrogallol | 5.32 ± 0.34 | 10 ± 0.5 | 29.1 ± 1.0 | 146.9 ± 4.0 |
CA:PCA | – | – | – | – | – | – | 2 | catechol + catechol | 13.28 ± 0.54 | 10 ± 0.5 | 143.9 ± 5.7 | 135.7 ± 13.1 |
2.2. In Vitro Antioxidant Capacity Assays
2.2.1. DPPH● Radical Scavenging Assay
2.2.2. O2●▬ Radical Anion Scavenging Activity
2.2.3. HO● Radical Scavenging Activity
2.3. Quantum Chemistry Computations
Compound | BDE a | IP b | PDE c | PA d | ETE e |
---|---|---|---|---|---|
3i | 324.4 | 826.2 | 169.0 | 759.2 | 684.8 |
3k | 323.7 | 803.8 | 192.5 | 760.3 | 683.1 |
3o | 306.4 | 796.1 | 189.2 | 749.3 | 676.6 |
3p | 290.2 | 795.2 | 118.3 | 677.4 | 732.3 |
Compound | Mulliken Spin Density | Natural Spin Density | ||||
---|---|---|---|---|---|---|
Radical Centre | Protocatechuic Fragment | Cinnamic Fragment | Radical Centre | Protocatechuic Fragment | Cinnamic Fragment | |
3i | 0.359 | 0.602 | 0.039 | 0.284 | 0.609 | 0.107 |
3k | 0.337 | 0.608 | 0.055 | 0.269 | 0.666 | 0.065 |
3o | 0.268 | 0.011 | 0.721 | 0.198 | 0.020 | 0.782 |
3p | 0.287 | 0.038 | 0.675 | 0.218 | 0.021 | 0.761 |
3. Experimental Section
3.1. General Remarks
3.2. Chemistry
3.2.1. General Procedure for One-Pot Synthesis of Polyhydroxy (E)-2-(1-Carboxy-2-phenylvinyl)-benzoic Acids 3a–p
(E)-2-(1-Carboxy-2-(2-hydroxyphenyl)vinyl)benzoic Acid (3b)
(E)-2-(1-Carboxy-2-(4-hydroxyphenyl)vinyl)benzoic Acid (3c)
(E)-2-(1-Carboxy-2-(2,4-dihydroxyphenyl)vinyl)benzoic Acid (3d)
(E)-2-(1-Carboxy-2-(2,5-dihydroxyphenyl)vinyl)benzoic Acid (3e)
(E)-2-(1-Carboxy-2-(2,3-dihydroxyphenyl)vinyl)benzoic Acid (3f)
(E)-2-(1-Carboxy-2-(3,4-dihydroxyphenyl)vinyl)benzoic Acid (3g)
(E)-2-(1-Carboxy-2-(3,4,5-trihydroxyphenyl)vinyl)benzoic Acid (3h)
(E)-2-(1-Carboxy-2-(2-hydroxyphenyl)vinyl)-4,5-dihydroxybenzoic Acid (3j)
(E)-2-(1-Carboxy-2-(2,4-dihydroxyphenyl)vinyl)-4,5-dihydroxybenzoic Acid (3l)
(E)-2-(1-Carboxy-2-(2,5-dihydroxyphenyl)vinyl)-4,5-dihydroxybenzoic Acid (3m)
(E)-2-(1-Carboxy-2-(2,3-dihydroxyphenyl)vinyl)-4,5-dihydroxybenzoic Acid (3n)
3.2.2. General Procedure for Derivatization of Polyhydroxy (E)-2-(1-Carboxy-2-phenylvinyl)benzoic Acids 3a–p
3.3. In Vitro Antioxidant Capacity Assays
3.3.1. 1,1-Diphenyl-2-picrylhydrazyl Radical Scavenging Assay (DPPH●)
3.3.2. Superoxide Anion Radical Scavenging Assay (O2●▬)
3.3.3. Hydroxyl Radical Scavenging Assay (HO●)
3.4. Statistical Analysis
3.5. Theoretical Approach
4. Conclusions
Supplementary Materials
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Miliovsky, M.; Svinyarov, I.; Prokopova, E.; Batovska, D.; Stoyanov, S.; Bogdanov, M.G. Synthesis and Antioxidant Activity of Polyhydroxylated trans-Restricted 2-Arylcinnamic Acids. Molecules 2015, 20, 2555-2575. https://doi.org/10.3390/molecules20022555
Miliovsky M, Svinyarov I, Prokopova E, Batovska D, Stoyanov S, Bogdanov MG. Synthesis and Antioxidant Activity of Polyhydroxylated trans-Restricted 2-Arylcinnamic Acids. Molecules. 2015; 20(2):2555-2575. https://doi.org/10.3390/molecules20022555
Chicago/Turabian StyleMiliovsky, Mitko, Ivan Svinyarov, Elena Prokopova, Daniela Batovska, Simeon Stoyanov, and Milen G. Bogdanov. 2015. "Synthesis and Antioxidant Activity of Polyhydroxylated trans-Restricted 2-Arylcinnamic Acids" Molecules 20, no. 2: 2555-2575. https://doi.org/10.3390/molecules20022555