This review discusses the antioxidant potential of oleanolic acid, a triterpene compound present in many medicinal and edible plants. The authors analyze various studies that confirm numerous pharmacological properties of this compound, such as its anticancer, antidiabetic, neuroprotective, osteoprotective, anti-obesity, and anti-inflammatory effects. OA, as a natural antioxidant, plays an important role in neutralizing reactive oxygen species, which contribute to the oxidative stress that is responsible for the development of many diseases, including cancer and cardiovascular and neurodegenerative diseases. This article also presents natural sources of OA, including grapes, olives, and apples, and discusses the mechanisms of its antioxidant action, including the inhibition of lipid peroxidation and the modulation of signaling pathways related to inflammatory processes. In addition, there are research results that indicate the therapeutic benefits of OA in the treatment of diabetes and neurodegenerative diseases, as well as its potential to protect the heart, liver, and kidneys from oxidative damage. In conclusion, OA has potent antioxidant properties that can be used in the prevention and treatment of many diseases related to oxidative stress. This article also presents the possibility of increasing the bioavailability of OA through the use of nanoparticle and liposome technology.

During the last few decades more and more attention has been paid to triterpenes—a group of compounds with five- or four-ring skeleton and carboxyl, hydroxyl or oxo groups. Triterpenes with unsubstituted C-3 hydroxyl group can be easily transformed into appropriate ketones and then into oximes. The carbonyl group can be created not only from the hydroxyl group at C-3 position, but also at C-2, C-12 or C-28 positions. Several methods of creation of two = NOH groups within one molecule of triterpene are known. There are also known triterpenes with two carbonyl groups, e.g. at C-3 and C-11 positions, which differ in reactivity: among them only C-3 group can be transformed into oxime. A reactive hydroxyimine group can undergo the action of acylating agents, such as carboxylic acids or their derivatives, also the ones with significant pharmacological activity. Acyl derivatives of triterpenic oximes exhibit important pharmacological activity. The biological tests performed with the use of cell cultures inoculated with viruses showed inhibitory activity of some triterpenic acyloximes against type 1 HSV (H7N1), ECHO-6 and HIV-1 viruses. Another acylated oximes derived from triterpenes shown cytotoxic or antiproliferative activity against many lines of cancer cells. In many cases the pharmacological effects of the tested acyloxyiminotriterpenes were comparable to those of appropriate standard drugs. One of the newest application of acyl derivatives of triterpenic oximes is their ability to form organogels.