Oleanolic acid or oleanic acid is a naturally occurring triterpenoid, widely distributed in food and medicinal plants, related to betulinic acid. It can be found in Phytolacca americana (American pokeweed), and Syzygium spp, garlic, etc. It is relatively non-toxic, hepatoprotective, and exhibits antitumor and antiviral properties.
Oleanolic acid was found to exhibit strong anti-HIV activity, the related compound betulinic acid was used to create the first commercial maturation inhibitor drug. It was first studied and isolated from several plants, including Rosa woodsii (leaves), Prosopis glandulosa (leaves and twigs), Phordendron juniperinum (whole plant), Syzygium claviflorum(leaves), Hyptis capitata (whole plant), and Ternstromia gymnanthera (aerial part). Other Syzygium species including java apple (Syzygium samarangense) and rose apples contain it.