| 1. |
- Ibewuike, Joseph C, et al.
(författare)
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Antiinflammatory and antibacterial activities of C-methylflavonols from Piliostigma thonningii
- 1997
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Ingår i: Phytotherapy Research. - 0951-418X .- 1099-1573. ; 11:4, s. 281-284
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Tidskriftsartikel (refereegranskat)abstract
- Newly described C-methylflavonols, 6,8-di-C-methylquercetin 3-methyl ether, 6-C-methylquercetin 3,7-dimethyl ether, 6,8-di-C-methylquercetin 3,7-dimethyl ether together with the known compounds quercetin, quercitrin, 6-C-methylquercetin 1-methyl ether, 6-C-methylquercetin 3,7,3'-trimethyl ether, 6,8-di-C-methylkaempferoI 3-methyl ether and 6,8-di-C-methylkaempferol 3,7-dimethyl ether isolated from the leaves of Piliostigma thonningii, were tested for their ability to inhibit prostaglandin synthesis in vitro and antibacterial activity against Staph, aureus, The influence of the B ring 3',4' diol group on the activity of C-methylflavonols in the inhibition of prostaglandin synthesis differ from that observed for a series of flavonoids without C-methyl groups, The antibacterial activity in the series mirror those of methylated antimicrobial flavonoids, The traditional uses of the plant in infections and inflammatory conditions were rationalized on the basis of the activities of these compounds.
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| 2. |
- Ibewuike, Jospeh C, et al.
(författare)
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Piliostigmin, a 2-phenoxychromone, and C-methylflavonols from Piliostigma thonningii
- 1996
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Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422 .- 1873-3700. ; 43:3, s. 687-690
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Tidskriftsartikel (refereegranskat)abstract
- Piliostigmin, a 2-phenoxychromone, and three C-methylflavonols, 6,8-di-C-methylquercetin 3-methyl ether, 6-C-methylquercetin 3,7-dimethyl ether and 6,8-di-C-methylquercetin 3,7-dimethyl ether, were isolated from the leaves of Piliostigma thonningii, together with the known compounds quercetin, quercitrin, 6-C-methylquercetin S-methyl ether, 6-C-methylquercetin 3,7,3'-trimethyl ether, 6,8-di-C-methyllraempferol 3-methyl ether and 6,8-di-C-methyllraempferol 3,7-dimethyl ether. The structures of the new compounds were established by spectral methods, especially 2D NMR. Complete C-13 assignments using HMBC experiments are reported for the four latter C-methylflavonols.
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