Kopsia indole alkaloids

Zhu, J., Guggisberg, A. and Hesse, M. 1986. Indole alkaloids from Kopsia haina-nensis. Planta Medica, 52 63-64. 

The monoterpenoid indole alkaloids constitute a laige group and careful investigation of plants, particularly from the Apocynaceae (Kopsia, Tabernaemontana, Alstonia, Leuconotis) and Rubiaceae (Uncaria, Mitragyna) have yielded many novel compounds. 

Pauciflorines A (268) and B (269) from Kopsia pauciflora are notable for being rare examples of plant-derived indole alkaloids which showed potent inhibitory activity (equivalent to that of the commercial compound, arbutin) towards melanin biosynthesis in cultured B16 melanoma cells at concentrations of 13 and 25 (ig/ml, respectively, without any cytotoxicity towards the cells [19,174,222]. 

The alkaloids of all other Kopsia species so far investigated belong to the tryptamine-secologanin indole alkaloid type commonly found in the Apocynaceae, of which Kopsia is a constituent genus. 

Jokela and Lounasmaa presented and C-NMR exact spectral data for seven types of ajmaline-type alkaloids from various species of the Dogbane family. These alkaloids are as follows ajmaline, 17-O-acetylajmaline, iso-ajmaline, isosandwichine, rauflorine, vincamajine, and vincamedine. Four steroidal alkaloids (conessine, holadysenterine, isoconessimine, and kurchessine) were found in the stem bark of Holarrhena antidysenterica Eleven indole alkaloids were isolated from the stem bark of Kopsia hainanensis Tsiang, which is a species of Kopsia, endemic in China. They are (—)-kopsinine, (—)-kopsinnic acid, (—)-kopsinoline, kopsinilam, kopsanome, (-h)-5,22-dioxokopsane, ebumamenine, (-i-)-ebumamine, (—)-isoebumamine, (-i-)-tubotaiwine, and (-i-)-kopsoffine. Moreover, from... 

Zhu J, Guggisberg A, Hesse M. Indole alkaloids from Kopsia hainanensis. Planta Med 1986 52 63. ... 

Yang Y, Zuo WJ, Zhao YX, Dong WH, Mei WL, Dai HF. Indole alkaloids from Kopsia hainanensis and evaluation of their antimicrobial activity. Planta Med 2012 78(17) 1881. ... 

New indole alkaloids (kopsihainin D, kopsihainin E, and kopsihainin F) isolated from the twigs of Kopsia hainanensis were tested biologically with Staphyllococcus aureus and showed significant antibacterial activity. " New alkaloids were significantly more active than known compounds from... 

Nitaphylline (572), was the only bisindole isolated from Kopsia teoi which otherwise provided a large number of new indole alkaloids. The mass spectrum... 

Six alkaloids (the kopsifolines), possessing the carbon skeleton corresponding to the novel venalstonine-like monomer in tenuiphylline, and constituting a new structural subclass of the monoterpenoid indole alkaloids, have since been obtained from another Malaysian Kopsia (361,362). 

In Fig. 4.5, other examples of indole alkaloids isolated from the genus Kopsia are depicted [36, 39—41]. In particular, the indoloazocine derivative lapideilectine B has been synthetized by Pearson and coworkers in 23 linear steps [42, 43]. 

Fig. 4.5 Structures of indole alkaloids present in plants of genus Kopsia...

The basic fraction of the ethanolic leaf extract of the Malaysian plant Kopsia griffithii exhibits a strong antileishmania activity. One of the two novel alkaloids isolated from this plant in 1998 was the indolizidino[8,7-fo]indole harmicine [17]. Synthetic approaches to harmicine became attractive owing to its pharmacological potential [18,19]. We applied our three-step pyrrolidine annulation strategy to the synthesis of harmicine (Scheme 15.5) [19]. 

Only one bisindole alkaloid, nitaphylline (313), was isolated from Kopsia teoi which otherwise provided a large number of new indoles. Nitaphylline [155,186] was shown to be a bisindole constituted from union of two kopsingine moieties. The mass-spectrum showed a molecular ion at m/z 910 with a significant peak at ndi 455 suggesting symmetrical cleavage of... 

A new monoterpene alkaloid, kinabalurine G (330) has been obtained from the leaf extract of Kopsia dasyrachis in addition to 11 known alkaloids and the novel pentacyclic indole, danuphylline vide infra) [223]. Analysis of the spectral data allowed assignment of the gross structure as well as determination of the stereochemistry at the various centers. Kinabalurine G (330) is the AZ-oxide of 9-hydroxy-S-skytanthine, which is unknown, although a 9-hydroxy-skytanthine of unknown stereochemistry has been previously reported from Tecoma stans [224]. 

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