Three New Alkaloids from the Leaves of Uncaria rhynchophylla |
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Authors: | Bin Ma Chun‐Fu Wu Jing‐Yu Yang Rui Wang Yoshihiro Kano Dan Yuan |
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Affiliation: | 1. Department of Traditional Chinese Medicines, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, P.?R. China (phone/fax: +86?24?2398?6502);2. Department of Pharmacology, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, P.?R. China |
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Abstract: | Three new alkaloids, 2′‐O‐β‐D ‐glucopyranosyl‐11‐hydroxyvincoside lactam ( 1 ), 22‐O‐demethyl‐22‐O‐β‐D ‐glucopyranosylisocorynoxeine ( 2 ), and (4S)‐corynoxeine N‐oxide ( 3 ) were isolated from the leaves of Uncaria rhynchophylla, together with four known tetracyclic oxindole or indole alkaloids, isocorynoxeine N‐oxide ( 4 ), rhynchophylline N‐oxide ( 5 ), isorhynchophylline N‐oxide ( 6 ), and dihydrocorynantheine ( 7 ), and an indole alkaloid glycoside, strictosidine ( 8 ). The structures of 1 – 3 were elucidated by spectroscopic methods including UV, IR, ESI‐TOF‐MS, 1D‐ and 2D‐NMR, as well as CD experiments. The activity assay showed that 8 (IC50=8.3 μM ) exhibited potent inhibitory activity on lipopolysaccharide(LPS)‐induced nitrogen monoxide (NO) release in N9 microglia cells. However, only weak inhibitory activities were observed for 1 – 7 (IC50>100 μM for 1 – 6 or >30 μM for 7 ). |
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Keywords: | Alkaloids Vincoside lactams, 11‐hydroxy‐ Isocorynoxeinic acids (4S)‐Corynoxeine N‐oxide Uncaria rhynchophylla Glucosides |
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