Molecular mechanism of apoptosis induction in Jurkat E6-1 cells by Tribulus terrestris alkaloids extract

The present study demonstrates apoptosis-inducing potential and mechanism of action of Tribulus terristris alkaloid extract in Jurkat E6-1 cancer cell line. Liquid Chromatography-Mass Spectrometry and High Resolution-Mass Spectrometry analysis identified the presence of four N-feruloyltyramine derivatives, namely trans-N-feruloyl-3-hydroxytyramine (1), trans-N-coumaroyltyramine (2), trans-N-feruloyltyramine (3) and trans-N-feruloyl-3-ethoxytyramine (4) in the alkaloid extract. Compounds 2 and 3 have not been yet reported in the alkaloid extract of T. terristris. In silico analysis revealed therapeutic potential of N-feruloyltyramine derivatives and strong binding efficiency to both chains of Tumor Necrosis Factor Receptor 1. Treatment of alkaloids extract to Jurkat E6-1 clone induced dose-dependent cytotoxicity (LC₅₀ 140.4 μg mL^-1). Jurkat cells treated with alkaloids extract at sub-lethal concentration showed DNA fragmentation, enhancement in caspase-3 activity and phosphatidylserine translocation (apoptosis indicator) compared to control cells. Gene expression analysis using Human Apoptosis RT² Profiler PCR Array analysis upon alkaloid treatment was found to significantly alter expression of critical genes such as TNFR1, FADD, AIFM, CASP8, TP53, DFFA and NFKB1. These genes are predicted to mediate apoptotic cell death via both intrinsic and extrinsic apoptosis pathway. In summary, we report the identification of new N-feruloyltyramine derivatives from alkaloid extract of T. terristris fruit with probable anti-leukemic and pharmacological potential.