Oleanolic acid or oleanic acid is a naturally occurring pentacyclic triterpenoid related to betulinic acid. It is widely distributed in food and plants where it exists as a free acid or as an aglycone of triterpenoid saponins.[2]
Oleanolic acid biosynthesis starts with mevalonate to create squalene. Squalene monooxygenase in the next step oxidases the squalene and forms an epoxide resulting in 2,3-oxidosqualene.[5] Beta-amyrin synthase creates beta-amyrin by a ring formation cascade.[5][6] After the formation of beta amyrin, CYP716AATR2, also known as a cytochrome p450 enzyme, oxidizes carbon 28 turning it into alcohol.[6] CYP716AATR2 converts the alcohol to aldehyde and finally to a carboxylic acid forming oleanolic acid.[6]
Pharmacological research
Oleanolic acid is relatively non-toxic, hepatoprotective, and exhibits antitumor and antiviral properties.[7] Oleanolic acid was found to exhibit weak anti-HIV[8] and weak anti-HCV activities in vitro, but more potent synthetic analogs are being investigated as potential drugs.[9]
A 2002 study in Wistar rats found that oleanolic acid reduced sperm quality and motility, causing infertility. After withdrawing exposure, male rats regained fertility and successfully impregnated female rats.[11] Oleanolic acid is also used as standard for comparison of hyaluronidase, elastase and matrix-metalloproteinase-1 inhibition of other substances in primary research (similar to diclofenac sodium for comparison of analgesic activity).[12][13]
^Mengoni F, Lichtner M, Battinelli L, Marzi M, Mastroianni CM, Vullo V, Mazzanti G (February 2002). "In vitro anti-HIV activity of oleanolic acid on infected human mononuclear cells". Planta Medica. 68 (2): 111–114. doi:10.1055/s-2002-20256. PMID11859458.
^Yu F, Wang Q, Zhang Z, Peng Y, Qiu Y, Shi Y, et al. (June 2013). "Development of oleanane-type triterpenes as a new class of HCV entry inhibitors". Journal of Medicinal Chemistry. 56 (11): 4300–4319. doi:10.1021/jm301910a. PMID23662817.