Studies on plants containing indole alkaloids. VIII. Indole alkaloid glycosides and other constituents of the leaves of Uncaria rhynchophylla Miq.

Advances in chemistry and bioactivity of the genus Uncaria

“…Hyperin (quercetin galactoside, 43d) and trifolin (kaempferol galactoside, 43e) were isolated from the leaves (Aimi et al, 1982). Hyperin was also reported from the branch (Han et al, 2000) and the stem (Jeoung et al, 2002).…”

“…Vallesiachotamine (17), vincoside lactam (16b), and strictosamide (16c) were also isolated from the same plant. These alkaloids have the unusual 15β-H stereochemistry (Aimi et al, 1982). Geissoschizine methyl ether (18) was isolated as a minor alkaloid from U. rhynchophylla (Aimi et al, 1977).…”

Antioxidant and Free Radical-Scavenging Activity of Choto-san and Its Related Constituents

“…Chotoko, the main medicinal plant in Choto-san, also contains many phenolic compounds including epicatechin, caffeic acid, and quercetin. 12,13) Previous studies have reported the antioxidant and free radical-scavenging activities of Chotoko. 9,10) Recently, the inhibitory effects of Choto-san and the hooks and stems of U. sinensis on free radical-induced lysis of rat red blood cells have been reported.…”

Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

“…Oxindole alkaloids, such as rhynchophylline (6), corynoxeine (7), isorhynchophylline (8), and isocorynoxeine (9), have been isolated mainly from the aerial parts, namely, hooks, stems, and leaves. From the : Corynoxeine (7) : Isorhynchophylline (8) : Isocorynoxeine (9) Corynanthé-type Oxindoles (1) : Hirsuteine (2) : Dihydrocorynantheine (4) : Corynantheine (5) leaves of this plant, glycoindole alkaloids, namely, strictosamide (10), vincoside lactam (11), and rhynchophine (12), have been isolated [10]. Geissoschizine (13), a demethyl derivative of 3, is one of the key intermediates in the biosynthesis of monoterpenoid indole alkaloids [1,11].…”

“…or related compounds, such as common monoterpenoid indole alkaloids [1]. By fragmentation of the aglycon of strictosamide (10) or that of vincoside lactam (11), the C4 unit was eliminated and subsequent oxidation (aromatization) of the D-ring produced nauclefidine (84). To prove this structure, the total synthesis of 84 was carried out.…”