LC-MS/MS identification and cytotoxic assessment of jaspamide and its congeners from the sponge Jaspis diastra

Abstract

Jaspamide (jasplakinolide; NSC-613009) is a cytotoxic cyclic polypeptide that was initially isolated from the sponge Jaspis cf. Johnston. It displayed anti-tumor, anti-fungal and insecticidal activities, among others. Herein, an LC-MS/MS approach for the identification of jaspamide (1) and its congeners in the extracts of the sponge Jaspis diastra, collected from the Mauritius waters, is described. Based on the interpretation of LC-MS/MS data and using the proposed fragmentation pattern of jaspamide (1) as a model, jaspamide (1) and its congeners were identified in the extracts. Jaspamide (1), Q, R and Z₁ were identified in hexane and ethyl acetate extracts whereas jaspamide (1) and Z₁ were identified in the methanol extract. The cytotoxic evaluation of the extracts revealed that the ethyl acetate extract was more active than the hexane and methanol extracts with IC₅₀ values of 1.60 ± 0.48 μg mL⁻¹ on A172, 1.71 ± 0.42 μg mL⁻¹ on TERA1, 1.05 ± 0.02 μg mL⁻¹ on DLD1 and 0.75 ± 0.04 μg mL⁻¹ on HaCaT. Subsequent fractionation of this extract by column chromatography resulted in the isolation of a precipitate (JC-1) which was characterized by 1D and 2D NMR as jaspamide (1). Semi-preparative HPLC of JC-1 resulted in a purified jaspamide (1) (JC-1P). The purity of JC-1P was determined by analytical HPLC using commercial jaspamide with a purity of ≥97% as the reference. JC-1P with a purity of 87.63 ± 1.33% displayed IC₅₀ values of 1.30 ± 0.05 μg mL⁻¹ on A172, 2.59 ± 0.33 μg mL⁻¹ on TERA1, 0.68 ± 0.11 μg mL⁻¹ on DLD1 and 0.82 ± 0.19 μg mL⁻¹ on HaCaT.