Document Type: Research article
Department of Pharmaceutical Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Protein Technology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran.
Department of Chemistry, College of sciences, Yazd University, Yazd, Iran.
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R. Iran
In this work, linear and cyclic disulfide heptapeptides of Longicalycinin A have been successfully synthesized by solid phase methodology with Fmoc /t-Bu and solution phase, respectively. 2-Chlorotrityl chloride resin (2-CTC) was used as a solid support. The synthesized linear disulfide analogue of Longicalycinin A was cleaved from the resin as a protected peptide. The final deprotection was performed by treatment with TFA 95% containing scavengers to achieve the deprotected linear disulfide analogue of Longicalycinin A which was characterized by different instrumental methods using LC-MS and FT-IR. Macrocyclization of deprotected linear peptide was done by an oxidating reagent. Linear and cyclic disulfide heptapeptides of Longicalycinin A were evaluated their toxic activity against cell lines of HepG2 and HT-29 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reagent in MTT assay. The synthetic analogues showed a relative good activity against cell lines of HepG2 and HT-29 with IC50 values from 10.33 µg/mL to 12.45 µg/mL, in comparison to the standard drug 5-fluorouracil (5-FU). Safety profiles of the synthesized linear and cyclic disulfide analogues of Longicalycinin A were also examined on skin fibroblast cells. Between the linear and cyclic disulfide heptapeptides of Longicalycinin A, the cyclic peptide showed a considerable toxic activity on the cancerous cell lines along with a low safety result on normal cells. Therefore, the linear disulfide heptapeptide of Longicalycinin A would be encouraging to develop new anticancer agents.