Assessment of Toxicity and Absorption of the Novel AA Derivative AA-Pme in SGC7901 Cancer Cells In Vitro and in Zebrafish In Vivo

BACKGROUND: Asiatic acid (AA; 2α,3β,23-trihydroxyurs-12-ene-28-oic acid) is an active compound derived from Centella asiatica, a traditional medicinal plant used widely in many Asian countries, particularly for the treatment of cancer. However, the modified AA derivative N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-l-proline methyl ester (AA-PMe) has shown markedly better anti-tumor activity than AA. MATERIAL/METHODS: We evaluated the toxicity of AA and AA-PMe on zebrafish morphology, mortality, and hatching rate and determined the effect on SGC7901 cancer cells by acute toxicity assay. AA-PMe absorption in vitro in SGC7901 cells and in vivo in zebrafish was determined by establishing a highly accurate and reproducible HPLC protocol. RESULTS: In zebrafish, the toxicity of AA-PMe was lower than AA, with an acute toxic dose of AA-PMe above 25 μM, compared to acute toxicity at doses above 10 μM for AA. However, chronic toxicity of AA-PMe began occurring at doses below 25 μM but became apparent for AA at doses below 10 μM. Although low doses of AA-PMe were tolerated acutely, it became chronically toxic during zebrafish development, resulting in morphological abnormalities, including peripheral and abdominal edema, hemorrhage, abnormal body shape, enlarged yolk sac, and reduced motility. At low concentrations, absorption of AA-PMe by cells and zebrafish embryos occurred in a dose-dependent manner, but this stabilized as the concentration increased. CONCLUSIONS: This pharmacokinetic study outlines the cellular and organismal effects of AA-PMe and suggests a theoretical basis that may underlie its mechanism of action.