Chemical constituents of Thai Piper ribesoides and their antiausterity activities against the PANC-1 human pancreatic cancer cell line

Abstract

A methanolic extract of Thai Piper ribesoides showed preferential cytotoxicity against PANC-1 human pancreatic cancer cells under a nutrient-deprived condition, with a PC₅₀ value of 24 μg/mL. Phytochemical investigation of this bio-active extract led to the isolation of six compounds (1-6), including two new polyoxygenated cyclohexane derivatives, named ribesoidones A and B (1 and 2). The structural elucidation of the new compounds was achieved by a combination of HREIMS, NMR, and circular dichroism spectroscopic analyses. Isolated compounds were tested for their antiausterity activity against PANC-1 human pancreatic cancer cell line. Among these, compounds 1, 3, and 4 displayed potent preferential cytotoxic activity with PC₅₀ values of 5.5-7.2 μM. Ribesoidone A (1) was also found to inhibit PANC-1 colony formation under normal nutrient-rich conditions.

Keywords: Cyclohexanones; PANC-1; Piper ribesoides; Preferential cytotoxicity.