Olive oleanolic acid

Triterpenic Acids. The following pentacyclic mono- and dihydroxy triterpenic acids are present in virgin olive oil (35, 43, 44) 3p-hydroxy-17-carboxy-5-12-olea-nene (oleanolic acid) 3 3,2a-dihydroxy-17-carboxy-5-12-oleanene (maslinic acid) 3p-hydroxy-17-carboxy-8-12-ursene (ursolic acid) 2a,3p-dihydroxy-17-carboxy-5-12-ursene (2a-hydroxyursolic acid) and deoxyursolic acid (structure not fully elucidated). 

Triterpenols and sterols are present as free or esterified with fatty acids (oleic acid and linoleic acid as the most relevant). Total content of triterpens is between 100-300 mg/100 g of oil. 24-Methylen-cycloartanol and cycloartenol are dominant. Erythrodiol, uvaol and triterpenic acids (ursolic, oleanolic acids etc) have been described in the imsaponifiable fraction of olive oil. The terpenoid fraction is complex and many constituents are still imdefined. 

Oleanolic acid has long been known as a constituent of olive oil. Methyl- and dimethylsterols are important in identifying fats and oils (cf. Fig. 3.44). 

The presence of oleanolic acid (a triterpenic acid, of the a-amyrin series), as a consistent component of the olive fruit and of its oil, has long been known (Canzoneri, 1906 Parisi and De Vito, 1931 Scurti and Tomasi, 1912). More recent is the identification of maslinic (Cag-lioti, 1961) and crategolic (Vioque et al., 1961) acids. The presence has yet to be confirmed in vegetable oils —in particular, olive oil— of other terpenic acids such as ursolic and betulinic (Mazuelos Vela, 1964 Thiers et al., 1959) these acids are very probably in free form in the oil. 

Continued efforts are still ongoing to find economical ways to isolate and purify these compounds [20], Furthermore, rme sees in olive pomace a source for squalene (16) [32], tocopherols (17) [33], D-marmitol (18) [34], triterpenes oleanolic (19) and maslinic (20) acids [35], pectic polysaccharides [13], hemicelluloses [36], and oligosaccharides [34]. 

Other nonphenolic compounds have also been extracted from olive leaves such is the case with terpenic acids including oleanolic, ursolic, and maslinic acids, which were extracted by Albi et al. [259]. Both maceration and Soxhlet extraction using hexane as extractant were used to remove terpenic dialcohols, triglycerides, a-tocopherol, ester waxes, squalene, and (3-carotene, among other substances [260]. The extraction efficiency was similar, the differences between the two methods never exceeding 5%. 

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