Studies on plants containing indole alkaloids. VI. Minor bases of Uncaria rhynchophylla Miq.

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

“…Along with these, such minor indole alkaloids as geissoschizine methyl ether (3), dihydrocorynantheine (4), and corynantheine (5) have been obtained (Fig. (1)) [9]. 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.…”

“…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].…”

Advances in chemistry and bioactivity of the genus Uncaria

“…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). The pyridino-indoloquinolizidinones 14a-c were reported in the leaves of this species (Phillipson et al, 1978).…”

Crystal Structure of Akuammigine Picrate Hydrate

“…On the basis of new 1 H-NMR data, the configuration of the MeÀC(19) group was assigned a and the configuration at C(20) of akuammigine was tacitly revised (thus epiallo) [20], and later the perils of assigning configuration of indole alkaloids based on chemical degradation were discussed [21]. Next, an equilibrium of two akuammigine conformers was observed by temperature-dependent 13 C-NMR [22] and was corroborated by circular dichroism (CD) [23] [24]. A third conformer, where ring D adopts a boat conformation, was invoked to give a better explanation of 1 H-NMR coupling constants [25].…”

“…[39] cell cultures, Asian Uncaria rhynchophylla Miq. [23], U. bernaysii F. Muell. [40], and U. attenuata Korth.…”