Betulinic acid is a naturally occurring pentacyclic triterpenoid which has antiretroviral, antimalarial, and anti-inflammatory properties, as well as a more recently discovered potential as an anticancer agent, by inhibition of topoisomerase.

[1] It is found in the bark of several species of plants, principally the white birch (Betula pubescens)[2] from which it gets its name, same as the bracket fungus Fomitopsis betulina, but also the ber tree (Ziziphus mauritiana), selfheal (Prunella vulgaris), the tropical carnivorous plants Triphyophyllum peltatum and Ancistrocladus heyneanus, Diospyros leucomelas, a member of the persimmon family, Tetracera boiviniana, the jambul (Syzygium formosanum),[3] flowering quince (Pseudocydonia sinensis, former Chaenomeles sinensis KOEHNE),[4] rosemary,[5] and Pulsatilla chinensis.

In neuroectodermal tumor cells, betulinic acid–induced apoptosis is accompanied by caspase activation, mitochondrial membrane alterations and DNA fragmentation.

[11] Betulinic acid induces apoptosis by direct effects on mitochondria, leading to cytochrome c release, which in turn regulates the "downstream" caspase activation.

[13] Alternatively, Rieber suggested betulinic acid exerts its inhibitory effect on human metastatic melanoma partly by increasing p53.

[14] The study also demonstrated preferential apoptotic effect of betulinic acid on C8161 metastatic melanoma cells, with greater DNA fragmentation and growth arrest and earlier loss of viability than their nonmetastatic C8161/neo 6.3 counterpart.

[18] A major inconvenience for the future clinical development of betulinic acid and analogues resides in their poor solubility in aqueous media such as blood serum and polar solvents used for bioassays.

Moreover, some C-28 amino acids and C-3 phthalates derivatives exhibited higher cytotoxic activity against cancer cell lines with improved selective toxicity and water solubility.

Recently, Gauthier et al. synthesized a series of 3-O-glycosides of betulinic acid which exhibited a strongly potent in vitro anticancer activity against human cancer cell lines.