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Oregano is a common culinary herb used as spice in different parts of the world. Origanum is a genus of Lamiaceae family with many species. Two species Origanum majorana L. and Origanum vulgare L. have therapeutic properties. Besides using as a spice in food, the herb has been used in treatment of some conditions including colds, respiratory allergies, gastrointestinal disorders, diabetes mellitus, wound healing and as a tranquilizer, in alternative medicine for centuries. Until now, numerous reports on its biological and pharmacological properties and also analysis of its extracts or oils have published. According to reliable scientific studies, Origanum spp. have a strong antioxidant and antimicrobial effects against common human and foodborne pathogens. Based on frequent biochemical analysis of extracts and essences of the herb, phenolic compounds especially phenolic acids and flavenoids are probable responsible agents. These days, investigations are focused on antidiabetic, antihypertensive, anti-inflammatory, cytotoxicity and antimutagenic action of genus Origanum, besides the antioxidant and antibacterial activities.

New synthetic routes to three possible stereoisomers of hyodeoxycholic (3 alpha, 6 alpha-dihydroxy-5 beta-cholanic) acid are described. The principal reactions involved were inversion at C-3 of 3 alpha-hydroxy-6-oxo derivatives with diethyl azodicarboxylate-triphenylphosphine-formic acid and with N,N-dimethylformamide, without allomerization to the more stable 5 alpha form. On the basis of physical and chromatographic data, previously reported 3 beta, 6 alpha-dihydroxy-5 beta-cholanic acid and its methyl ester are shown to be C-3 epimeric mixtures. The 13C nuclear magnetic resonance spectra were of key importance in characterizing the stereoisomers and estimating their purity.

The complete set of the eight theoretically possible stereoisomeric 3,6,7-trihydroxy-5 beta-cholanic acids, four of which are new, related to hyocholic and muricholic acids were prepared from chenodeoxycholic acid. The principal reactions used were 1) cis-dihydroxylation of delta 6-compounds with osmium tetroxide/N-methylmorpholine N-oxide; 2) trans-dihydroxylation of 6 alpha, 7 alpha-epoxy compounds with boron trifluoride etherate in N,N-dimethyl-formamide; 3) inversion of equatorial 3 alpha-hydroxylated compounds to the corresponding 3 beta-epimers with diethyl azodicarboxylate/triphenylphosphine/formic acid; and 4) stereoselective reduction of 7-keto derivatives with zinc borohydride (or sodium borohydride) and by metallic potassium/tert-amyl alcohol.