Partial synthesis of C-ring derivatives from oleanolic and maslinic acids. Formation of several triene systems by chemical and photochemical isomerization processes

Gastroprotective and ulcer-healing activity of oleanolic acid derivatives: In vitro–in vivo relationships

“…Some 0.20 g of 1 was treated with m-chloroperbenzoic acid in dichloromethane affording after column chromatography 0.07 g (31%) of 7. The spectroscopic data are in agreement with those reported by García-Granados et al (2004). The obtention of compounds 5-6 can be explained considering that the experimental conditions favoured formation of other products in addition to the 3-oxo derivatives.…”

Biotransformation of oleanolic and maslinic methyl esters by Rhizomucor miehei CECT 2749

“…Its spectroscopic data were consistent with a structure of methyl 2a,3b-dihydroxyoleana-9(11),12-dien-28-oate, a compound previously synthesised by our group from compound 4 with NBS/AIBN (Garcia-Granados et al, 2004). A possible mechanism to explain the formation of the 9(11)-double bond of this metabolite (9) could be similar to that proposed for metabolite 5.…”

“…This substrate (6) was achieved by treating of methyl oleanolate (3) with NBS/AIBN (Garcia-Granados et al, 2004). Thus, the microbial incubation of 6 with R. miehei for 13 days resulted in the recovery of 62% of the substrate (6), and the isolation of metabolite 5 (11%), and a new metabolite 7 (8%) (Fig.…”

“…Next, we proceeded as described above in the incubation of substrate 3 with the same microorganism. The resulting mixture of compounds was chromatographed on a silica-gel column to provide 378 mg of starting material (4, 63%), 74 mg of methyl 2a,3b,30-trihydroxyolean-12-en-28-oate (8, 12%), 41 mg of methyl 2a,3b-dihydroxyoleana-9(11),12-dien-28-oate (9, 7%) (Garcia-Granados et al, 2004). The rest of the fractions (50 mg, 8%) were acetylated with Ac 2 O (2 ml) in pyridine (4 ml).…”

Ursolic Acid and Its Derivatives as Bioactive Agents

“…Liposomal ursolic acid (LUA) was used as a fresh drug in normal young volunteers and in individuals with developed solid tumours in order to determine the highest permitted level (MTD), dose-limiting toxicities (DLTs), and UA pharmacokinetics. A total sample of LUA (11,22,37,56,74,98 and 130 mg/m2) was given to 63 subjects (4 patients, 35 healthy participants and 24 adults). For the first season, clinical information revealed that LUA had manageable 98 mg/m 2 MTD toxicity.…”