Pharmacokinetics in mouse and comparative effects of frondosides in pancreatic cancer

The frondosides are triterpenoid glycosides from the Atlantic sea cucumber Cucumaria frondosa. Frondoside A inhibits growth, invasion, metastases and angiogenesis and induces apoptosis in diverse cancer types, including pancreatic cancer. We compared the growth inhibitory effects of three frondosides and their aglycone and related this to the pharmocokinetics and route of administration. Frondoside A potently inhibited growth of pancreatic cancer cells with an EC50 of ∼1 μM. Frondoside B was less potent (EC₅₀ ∼2.5 μM). Frondoside C and the aglycone had no effect. At 100 μg/kg, frondoside A administered to CD₂F₁ mice as an i.v. bolus, the Cp_max was 129 nM, Cl_tb was 6.35 mL/min/m², and half-life was 510 min. With i.p. administration the Cpmax was 18.3 nM, Cl^tb was 127 mL/min/m² and half-life was 840 min. Oral dosing was ineffective. Frondoside A (100 μg/kg/day i.p.) markedly inhibited growth cancer xenografts in nude mice. The same dose delivered by oral gavage had no effect. No evidence of acute toxicity was seen with frondoside A. Frondoside A is more potent inhibitor of cancer growth than other frondosides. The glycoside component is essential for bioactivity. Frondoside A is only effective when administered systemically. Based on the current and previous studies, frondoside A appears safe and may be valuable in the treatment of cancer.