To further investigate on the structure-activity relationships of immunosuppressive Astin C, seventeen analogues 1–17 were designed and synthetized via amino acid substitution strategy by the solid-phase peptide synthesis method for the first time. In comparison with Astin C (IC₅₀ = 12.6 ± 3.3 μM), only compounds 2 (IC₅₀ = 38.4 ± 16.2 μM), 4 (IC₅₀ = 51.8 ± 12.7 μM), 5 (IC₅₀ = 65.2 ± 15.6 μM), and 8 (IC₅₀ = 61.8 ± 12.4 μM) exhibited immunosuppressive activity in the Lymph node cells of mice. These results showed that the Astin C analogues containing _D-amino acid residues, hydrophobic long-chain alkyl substituents, and aryl substituents performed better than those carrying hydrophilic amino acid residues and short-chain alkyl substituents. Moreover compounds 15, 16, and 17 had no immunosuppressive activity, which suggested that cis-3,4-dichlorinated proline played an important role in the immunosuppressive activity of Astin C.

对免疫抑制阿斯廷C的结构-活性关系进一步调查，17个类似物1 - 17设计并synthetized经由通过首次固相肽合成方法的氨基酸取代的策略。与Astin C（IC ₅₀  = 12.6±3.3μM）相比，仅化合物2（IC ₅₀  = 38.4±16.2μM），4（IC ₅₀  = 51.8±12.7μM），5（IC ₅₀  = 65.2±15.6μM），和8（IC ₅₀ = 61.8±12.4μM）在小鼠的淋巴结细胞中表现出免疫抑制活性。这些结果表明，含有_D-氨基酸残基，疏水性长链烷基取代基和芳基取代基的Astin C类似物的性能优于带有亲水性氨基酸残基和短链烷基取代基的那些。此外化合物15，16和17没有免疫抑制活性，这表明顺式-3,4-二氯代脯氨酸阿斯廷C的免疫抑制活性中起重要作用