• YAKHAK HOEJI
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• v.26 no.1
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• pp.1-8
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• 1982

Derivation of triterpenoids and then the screening for corticomimetics among them is our primary interest. $C_{11}$-oxo-triterprenoids except glycyrrhetinic acid are rarely found in the plant kingdom. Based on the facts that $C_{3}$ and $C_{11}$-Oxo-group are essential for the corticoid-like-activity through its competitive inhibition on the corticoid-5.betha.-reductase, it was attempted to produce artificial inhibitor on the enzyme by introducing $C_{11}$-oxo group to the triterpenoids of oleanene series such as oleanolic acid and hederagenin. We could obtain the $C_{11}$-oxo-oleanolic acid m.p. $264-6^{\circ}$, uv ${\lambda}max$ 249 and $C_{11}$-oxo-hederagenin amorp. uv ${\lambda}max$ 251 by acetylation, $CrO_{3}$-oxid., and deacetylation. Glycyrrhetinic acid, a natural 11-oxo-compound and the other 11-oxo-derivatives of oleanolic acid and hederagenin were compared in their inhibitory activity on the corticoid-5.betha.-reductase. The inhibitory activity of those compound were decreased in the order of $C_{11}$-oxo-oleanolic acid, $C_{11}$-oxo- hederagenin, glycyrrhetinic acid. This suggests more strong corticomimetic activity of those artificially derived $C_{11}$-oxo-oleanolic acid and $C_{11}$-oxa-hederagenin. Their Ki value were $4.6{\times}10^{-4}M$ and $5.8{\times}10^{-4}M$ respectively.

• Archives of Pharmacal Research
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• v.8 no.4
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• pp.237-242
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• 1985

11-Keto-derivatives of pomolic acid, $\beta$-boswellic acid and presenegenin were compared with those of oleanolic acid, hederagenin and glycyrrhetinic acid in respects of inhibitions on corticoid-5.betha.-reductase and anti-inflammatory activities. Hyddrophilicity of ring A and hydrophobicity of rings C/D enhanced the inhibition on the enzyme. However, the former induced edema and the latter caused to exhibit anti-inflammatory activity.

• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.178-183
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• 1986

It was our working hypothesis that introduction of 11-keto groups to 12-oleanene/ursene series of triterpenoids should endow them with corticoid-like activities, since pharmacological actions of glycyrrhetinic acid (GA) are known to be caused by inhibition on $corticoid-{\delta}^4-reductase$. 11-Keto-triterpenoids derived artificially in these studies, such as 11, 19-diketo-18, 19-secoursolic acid methyl ester(I), $11-keto-{\beta}-boswellic$ acid derivatives (IIa-IIc), 11-Keto-presenegenin dimethyl ester (III), II-keto-oleanolic acid derivatives (IVa-IVd) and 11-keto-hederagenin (V) possess the fundamental functions of ${\alpha},\;{\beta}-unsaturated$ ketone on C-11 and hydroxyl group on C-3, as like GA (VI). Additionally, they involve the carboxyl groups on rings A (II, III), D (I, III, IV, V) and E (VI), and the hydroxyl groups on rings A (III, V) and C (III). All the compounds competitively inhibited $corticoid-5{\beta}-reductase$, and the highest inhibitory potency appeared in I. All of them except $3,\;11-diketo-{\beta}-boswellic$ acid methyl ester (IIc) were more effective about five times to twice than GA. On carrageenin-induced edema test, compounds I and IVa-IVd showed anti-inflammatory activities, but III enhanced rather edema. Structure-activity relations were found in the aspects of hydrophilicity of ring A and hydrophobicity of rings C/D. The more they were hydrophilic in ring A and hydrophobic in rings C/D, the more they inhibited the enzyme. And the more they were hydrophobic in rings C/D, the more they exhibited antiiflammatory activities. However, the increased hydrophilicity in ring A resulted in increasing edema, probably due to a nonspecific inhibition on $aldosterone-5{\beta}-reductase$.