Lupeol anti-inflammatory activity

The triterpene-enriched fraction of the supercritical CO2 extract of the dried flowers of Calendula officinalis (Asteraceae) inhibited the croton oil-induced ear edema in mice. Of the identified compounds, the faradiol monoesters, lupeol, F-taraxasterol and a mixture of taraxasterol/ 5-amyrin were tested for their anti-inflammatory activity. Faradiol, obtained by hydrolysis of the extract, was the most active compound. It showed a dose-dependent effect with a potency that equals that of indomethacin at 0.14 fimol/cm2 (48% and 47% edema inhibition, respectively). The esterification of faradiol resulted in a reduction of more than 50% in the activity (only 31% inhibition was observed at 0.14 pmol/cm2), whereas 4/-taraxasterol, a C-16P dehydroxylated derivative of faradiol, was less active (47% inhibition at a dose of 0.28 pmol/cm2) [43]. 

The volatile oil has antiseptic and astringent properties (gosselin). The essential of bay inhibits the in vitro growth of E. coli (non-toxigenic strain 0157 H7). In animal models of inflammation, lupeol, from the leaves of P. racemosa var. ozua, and abietic acid from the leaves of P. racemosa var. grisea have shown anti-inflammatory activity in rats when applied topically or by the oral route. 

Among five triterpenoids isolated from Calendula officinalis flowers, P-amyrin (119), faradiol (232), i /-taraxasterol (238), taraxasterol (239), and lupeol (238), the diol 232 was the most active. It showed a dose-dependent effect with a potency that equals that of indomethacin (5) in the topical anti-inflammatory assay with croton oil [33]. Esterification at C-3 of 232 with a fatty acid reduced the activity by more than 50% [33] consistent with our observation in the TPA-induced assay described above. The anti-inflammatory properties, as determined by croton oil-induced edema of mouse ear, of faradiol-3-O-myristate (233) and its 3-O-palmitate (234), the main components of lipophilic extracts of C. officinalis flowers, were shown to be contribute significantly to the pronounced antiphlogistic activity of the lipophilic extracts of C. officinalis flowers [34]. 

The hydrophobic triterpenoids a-amyrin and lupeol (both having a 3-hydroxy as the only polar group) and their palmitate and linoleate esters are similarly potent and relatively selective inhibitors (IC50 = 4-9 pM). These triterpenoids are in vivo anti-inflammatory agents, and their relatively selective PICA inhibition activity suggests that PKA could be involved in the inflammatory process although the responsible mechanisms are not yet clear [90]. 

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