Alkaloids from Chinese Traditional Medicinal Plants

These alkaloids are widely used today in the treatment of hypertension. Medicinally, the most important alkaloids of Veratrum are the polyesters of protoverine (87) that have hypotensive properties. Plants from Veratrum and Fritillaria have been used in Chinese traditional medicine (Han et al., 1988). 

The club moss Huperezia serrata has long been used in Chinese traditional medicine. An alkaloid from this plant, huperzine A (60) is one of the few drugs that appears to... 

Another approach to the generation of an iminium cation suitable for cyclization is the protonation of dihydropyridine derivatives. One example can be found in Scheme 48, where treatment of compound 243 with acid induced its cyclization to indoloquinolizine 244, a precursor in the first total synthesis of (i)-tangutorine 245, an alkaloid isolated from a traditional Chinese medicinal plant <2001TL6593>. 

The structures of sclerophytins A 17 and B 18, isolated from the soft coral Sclerophytum capitalis, were revised on basis of spectroscopic re-evaluation . Two unusual flavonoid tetrahydrofuranyl skeletons, namely tephrorin A 19 and B 20, were identified from Tephrosia purpurea . An alkaloid cartormin 21 was isolated and identified from Carthamus tinctorius, a plant used widely as a traditional Chinese medicine, <00TL1955>. 

Evodiamine (16) is an indoloquinazoline alkaloid of mixed biosynthetic origin and possesses three nitrogen atoms arising from tryptophan and Af-methyl-anthranilic acid residues [78]. It is chief alkaloid from fruits of Evodia rutaecarpa Bentham (Rutaceae), a plant widely used by traditional Chinese medicine [79]. 

Febrifugine was first isolated from roots of Dichroa febrifuga Lour. (Saxifragaceae), a Chinese medicinal plant traditionally used to treat malaria fevers. This alkaloid showed potent anti-Plasmodium activity, which was superior to quinine, and tmacceptable side effects, such as hepatotoxicity and severe emesis [128,129]. Its properties not only precluded its use as drug but also encouraged the synthesis of safer analogues [127]. 

Incarvillea sinensis has been used in traditional Chinese medicine as a drug to treat rheumatism and relieve pain. Incarvillateine is a monoterpene alkaloid isolated from this plant. When intraperitoneally... 

The anthelmintic activity of the quinolizidine alkaloids has been reviewed [394]. It is well recognised that quinolizidine alkaloids deter or repel insects and non-insect herbivores [394], These compounds can interfere with protein biosynthesis and some bind to acetylcholine receptors with high affinity. (-)-N-methylcytisine (233) and (-)-anagyrine (234) were isolated from the roots of Sophora flavescens, a plant used in traditional Chinese medicine as an anthelmintic. N-methyl cytisine was twice as active as anagyrine but only half as active as (-)cytisine and nicotine [395,396] The alkaloids (3-6 pg) inhibited reproduction of B. xylophilus in the cotton balls assay. 

Pyrido[l,2-fl]azepine core is common to a group of alkaloids extracts from Stemona plants (Stemonaceae). Stemona together Pentastemona, Croomia, and Stichoneuron are four genera of Stemonaceae. The roots of three species, Stemona tuberosa, Stemona japonica, and Stemona sessifolia, have been used for centuries in traditional Chinese medicine for a variety of purposes such as treatment of cough, bronchitis, tuberculosis, pertussis, and as antiparasitic agents [1-5],... 

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