Alkaloids from the leaves of Uncaria rhynchophylla and their inhibitory activity on NO production in lipopolysaccharide-activated microglia.
Two new isomeric alkaloids, 18,19-dehydrocorynoxinic acid B (1) and 18,19-dehydrocorynoxinic acid (2), were isolated from the CHCl3 extract of the leaves of Uncaria rhynchophylla, together with four known rhynchophylline-type alkaloids, corynoxeine (3), isocorynoxeine (4), rhynchophylline (5), and isorhynchophylline (6), and an indole alkaloid glucoside, vincoside lactam (7). The structures of compounds 1 and 2 were elucidated by spectroscopic methods including UV, IR, HREIMS, 1D and 2D NMR, and CD experiments. The activity assay showed that compounds 3-6, with a C-16 carboxylic ester group, and 7 exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary cultured rat cortical microglia (IC 50: 13.7-19.0 microM). However, only weak inhibitory activity was observed for compounds 1 and 2, with a C-16 carboxylic acid group (IC 50: >100 microM).
Yuan
Dan
D
Department of Traditional Chinese Medicines, Shenyang Pharmaceutical UniVersity, 103 Wenhua Road, Shenyang 110016, People's Republic of China. yuandan_kampo@163.com
Ma
Bin
B
Wu
Chunfu
C
Yang
Jingyu
J
Zhang
Lijia
L
Liu
Suiku
S
Wu
Lijun
L
Kano
Yoshihiro
Y
D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D000818:Animals; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017628:Microglia / Q000187:drug effects; D015394:Molecular Structure; D009569:Nitric Oxide / Q000096:biosynthesis*; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D032070:Uncaria / Q000737:chemistry*
C531543:18,19-dehydrocorynoxinic acid; C531542:18,19-dehydrocorynoxinic acid B; D000470:Alkaloids; D004365:Drugs, Chinese Herbal; D008070:Lipopolysaccharides; D009569:Nitric Oxide