Abstract
A series of porphyrin derivatives <b>2a–f</b> was synthesized, namely, 5,10,15,20-<i >meso</i>tetrakis[<i >p</i>-methoxyphenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2a</b>), 5,10,15,20-<i >meso</i>tetrakis[2,6-dichloro-phenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2b</b>), 5,10,15,20-<i >meso</i>tetrakis[4-hydroxy-3,5-dimethoxyphenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2c</b>), 5,10,15,20-<i >meso</i>tetrakis[3,4-dimethoxyphenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2d</b>), 5,10,15,20-<i >meso</i>tetrakis[2,4-dichlorophenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2e</b>), and 5,10,15,20-<i >meso</i>tetrakis[3,4,5-trimethoxyphenyl]-21<i >H</i>,23<i >H</i>-porphyrin (<b >2f</b>), in high yields using a new method via a capping mechanism. These dyes were used as a model to study the free radical-induced damage of biological membranes and the protective effects of these porphyrins. It was demonstrated that these dyes were effective in the inhibition of the free radical-induced oxidative haemolysis of rat blood cells. Dyes <b >2d</b> and <b >2f</b> which bear methoxy functionality exhibited markedly higher antihaemolysis activity than the other analogs. Molecular modeling methods using ZINDO/INDO-1, with a configuration interaction of 26, and TD-DFT using the energy functional B3LYP and the basis set DGTZVP were used to study the vertical electronic excitations of porphyrins <b >2a–f</b> and it was shown that the <svg style="vertical-align:-3.39069pt;width:30.674999px;" id="M1" height="16.450001" version="1.1" viewBox="0 0 30.674999 16.450001" width="30.674999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x1D706" d="M529 97q-70 -109 -136 -109q-41 0 -56 94q-23 144 -37 284q-38 -88 -99 -202.5t-93 -156.5q-26 -8 -76 -19l-9 21q71 78 145.5 193t124.5 232q-5 84 -15 128q-12 55 -29.5 75.5t-42.5 20.5q-21 0 -45 -13l-8 24q16 17 46 30t55 13q43 0 70 -46.5t40 -169.5
q27 -249 51 -392q7 -46 23 -46q24 0 70 60z" /></g> <g transform="matrix(.012,-0,0,-.012,9.45,16.25)"><path id="x6D" d="M797 0h-214v26q46 5 58 17.5t12 63.5v167q0 116 -88 116q-48 0 -112 -52q3 -18 3 -42v-195q0 -46 11 -58t53 -17v-26h-214v26q48 5 59.5 17t11.5 60v172q0 115 -88 115q-47 0 -109 -52v-235q0 -47 10 -59.5t48 -17.5v-26h-211v26q50 5 62.5 17t12.5 60v207q0 48 -9 59.5
t-52 18.5v23q79 14 139 41v-81q3 2 29 20.5t44 29.5q45 28 81 28t66 -22t46 -61q25 20 83 57q39 26 76 26q59 0 93 -40t34 -113v-193q0 -49 10.5 -60.5t54.5 -16.5v-26z" /></g><g transform="matrix(.012,-0,0,-.012,19.159,16.25)"><path id="x61" d="M433 39l-85 -51q-27 0 -47 20q-16 16 -24 44q-5 -3 -24 -16.5t-27 -18.5t-23 -13.5t-25 -12t-19 -3.5q-52 0 -86 36.5t-34 85.5q0 71 81 99q128 43 155 65v17q0 54 -23 83.5t-62 29.5q-28 0 -45 -19t-29 -66q-7 -23 -29 -23q-15 0 -29 13t-14 30t31 40q25 19 68.5 40.5
t81.5 29.5q49 0 82 -27q45 -39 45 -123v-185q0 -60 35 -60q18 0 36 11zM275 84v156q-12 -6 -49 -23t-41 -19q-31 -14 -46 -31t-15 -43q0 -35 22.5 -55.5t48.5 -20.5q19 0 42 10.5t38 25.5z" /></g><g transform="matrix(.012,-0,0,-.012,24.383,16.25)"><path id="x78" d="M474 0h-214v26q32 4 39 12t-5 28l-74 117q-39 -58 -64 -106q-16 -25 -10 -35t44 -16v-26h-186v26q46 6 64 17t48 49t85 120l-87 136q-23 36 -40 47t-58 16v26h199v-26q-31 -4 -36.5 -12.5t9.5 -29.5l59 -93q37 56 58 94q13 23 7 30t-40 11v26h183v-26q-47 -5 -65 -13.5
t-45 -39.5q-24 -29 -78 -110l97 -148q28 -43 46.5 -55.5t63.5 -18.5v-26z" /></g> </svg> calculated using TD-DFT method was in excellent agreement with the experimental results, while the ZINDO method was inferior. Moreover, excellent correlation between the LUMO energy and cytotoxicity of dyes <b >2a–f</b> was found.
Highlights
Meso-substituted porphyrins were widely used as key components in constructing porphyrin-based model systems as well as molecular materials [1,2,3,4]
Studies pertaining to the kinetics and mechanisms of natural antioxidants [16,17,18] have demonstrated that simple structural modification of resveratrol, an antioxidant in red wine, significantly enhances its antioxidant activity [19,20,21,22] and cytotoxicity towards cancer cells [23]. With this background in mind, we report results from the synthesis of a series of porphyrin derivatives and an in vitro study of their protective effects on free radicalinduced haemolysis of rat red blood cells (RBCs)
The six porphyrin derivatives 2a–f are not novel, they were synthesized via a new method, the capping mechanism, which led to significantly high-yield porphyrins, and these dyes were screened for antioxidant and antitumor activity in which dyes 2d and 2f which bears methoxy functionality exhibited markedly higher anti-haemolysis activity than the other analogs
Summary
Meso-substituted porphyrins were widely used as key components in constructing porphyrin-based model systems as well as molecular materials [1,2,3,4]. Studies pertaining to the kinetics and mechanisms of natural antioxidants [16,17,18] have demonstrated that simple structural modification of resveratrol, an antioxidant in red wine, significantly enhances its antioxidant activity [19,20,21,22] and cytotoxicity towards cancer cells [23] With this background in mind, we report results from the synthesis of a series of porphyrin derivatives and an in vitro study of their protective effects on free radicalinduced haemolysis of rat red blood cells (RBCs). Since the lipid peroxidation is a free radical chain reaction and one initiating radical could induce up to fifty propagation reactions, the RBC membrane is quickly damaged, leading to haemolysis. The dyes studied were 5,10,15,20-mesotetrakis[p-methoxyphenyl]-21H,23H-porphyrin (2a), 5,10,15,20-mesotetrakis[2,6-dichlorophenyl]-21H,23H-porphyrin (2b), 5,10,15,20mesotetrakis[4-hydroxy-3,5-dimethoxyphenyl]-21H,23H-porphyrin (2c), 5,10,15,20-mesotetrakis[3,4-dimethoxyphenyl]21H,23H-porphyrin (2d), 5,10,15,20-mesotetrak-is[2,4-dichloro-phenyl]-21H,23H-porphyrin (2e), and 5,10,15,20-mesotetrakis[3,4,5-trimethoxy-phenyl]-21H,23H -porphyrin(2f )
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
