Chemical Constituents of Propolis from Myanmar and Their Preferential Cytotoxicity Against a Human Pancreatic Cancer Cell Line
J. Nat. Prod, July 2, 2009
A methanolic extract of propolis obtained in Myanmar was found to inhibit PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions (NDM), with a PC50 value of 9.3 μg/mL.
Bioactivity-guided fractionation of the extract led to the isolation of two new cycloartane-type triterpenes, (22Z,24E)-3-oxocycloart-22,24-dien-26-oic acid (1) and (24E)-3-oxo-27,28-dihydroxycycloart-24-en-26-oic acid (2), together with 13 cycloartanes (3−13) and four known prenylated flavanones (14−17).
Among these, compound 1 exhibited the most potent preferential cytotoxicity (PC50 4.3 μM) in a concentration- and time-dependent manner. Furthermore, 1 induced apoptosis-like morphological changes of PANC-1 cells within 24 h of treatment.