Alkaloids from Higher Plants

Murrayastine (13), C16H17NO3 (M 271.1191) was isolated from the dried bark of Mur ray a euchrestifolia as a syrupy liquid by Furukawa et al 41). Its uv absorption spectrum 224, 247, 255, 298, 332 and 336 nm) and ir spectrum showed the presence of carbazole skeleton. NMR data showed the presence of one aryl methyl (8 2.47), and three aryl methoxy (83.95, 3.96 and 4.00) groups. The me/a-coupled H-4 (87.32) and H-2 (8 6.65) signals and their enhancements after irradiation of the aromatic C-methyl showed that C-2 and C-4 were unsubstituted and that the methyl occupied position 3. Presence of the ortho coupled signal of H-5 (/ = 8 Hz) showed that both C-5 and C-6 were unsubstituted. Hence murrayastine could be formulated as l,7,8-trimethoxy-3-methyl carbazole which has been confirmed by synthesis vide p. 97). 

Murrayaline (14) C HisNOa (M 269.1002), m.p. 248-50° was isolated as a pale yellow prism from the bark of M. euchrestifolia 41). Its 

The isolation of carbazole (1), 3-methylcarbazole (2), and several oxidized derivatives of 3-methylcarbazole from taxonomically related higher plants of the genera Glycosmis, Glausena, and Murraya (family Rutaceae) indicates that the aromatic methyl group of the biogenetic key intermediate 3-methylcarbazole can be eliminated oxidatively (5,6). Most of the carbazole alkaloids isolated from the 

parviflora (Sims) Little G. mauritiana Tanaka G. montana Pierre 

Micromelum ceylanicum Wight M. hirsutum Oliver Ekebergia senegalensis Fuss. 

Cimicifuga simplex Wormsk. ex EXI. StreptoverticilUum ehimense S. mobaraense 

staurosporeus Anaya Actinomadura madurae A. melliaura Arcyria denudata Aspergillus flavus A. tubingensis Nocardia aerocoligenes Nocardiopsis dassonvillei Nocardiopsis sp. 

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Fig. 1. The characteristic types of peptide alkaloids from higher plants.

Fig. 10. Macrocyclic spermidine and spermine alkaloids from higher plants.

On the other hand, their occurrence in plants is restricted to some specific genera or even species from different families without a distribution pattern. The only exception is Pilocarpus Vahl (Rutaceae) in which all the species are known to accumulate imidazole alkaloids. No new sources from these alkaloids from higher plant have been reported since 1990. 

Antitumor compounds, among them cyclic peptides, terpenoids, and alkaloids isolated from higher plants 99YZ529. 

Several hypotheses have been proposed for the biogenesis of carbazole alkaloids (see Chapter 3 of this review). However, there is no deep experimental knowledge of the biosynthesis of this class of alkaloids. A comparison of the structural features of carbazole alkaloids isolated from higher plants suggests that 3-methylcarbazole (2) may represent the key intermediate in their biosynthesis (Scheme 1.1). 

While 1- and 2-oxygenated tricyclic carbazole alkaloids were isolated primarily from higher plants, various tricyclic carbazole alkaloids, which are 3-oxygenated or 3,4-dioxygenated, were obtained from alternative natural sources, such as microbial, marine, and mammalian sources. 

Wu, W. N., Beal, J. L., Clark, G. W. and Doskotch, R. W. 1976. Antimicrobial agents from higher plants. Additional alkaloids and antimicrobial agents from Thalictrum rugosum. Lloydia, 39 65-75. 

Another observation of similar importance is the first isolation of an alkaloid of the peptide type from higher plants. Ergosine (20) (and ergosinine) as well as agroclavine were found in Ipomoea argyrophylla Vatke (21). 

Alkaloids are an important class of compounds that have pharmacological effects on various tissues and organs of humans and other animal species. More than 16,000 are known and most are derived from higher plants. Alkaloids have also been isolated from microorganisms, from marine organisms such as algae, dinoflagellates, and puffer fish, as well as from terrestrial animals, such as insects, salamanders, and toads. 

Two new types of polyhydroxylated alkaloids containing dihydroxypyrrolidine moieties as glycosidase inhibitors from higher plants 02H(57)1539. 

A lot of anticancerous agents have been isolated from natural sources especially from microorganisms and plants. However, there is no one special type of compound for cancer therapy various types of substances are effective for various types of cancers and tumors, for instance, alkaloids, lignans, terpenes and steroids [1]. In this report, concentrates on those antitumor compounds isolated from higher plants. 

In this chapter, cyclic peptide alkaloids are discussed in Section II and cyclic oligopeptides from higher plants are discussed in Section III. 

In this chapter we describe cyclopeptide alkaloids, spermine and spermidine alkaloids, long-chain acid amides, and the cyclic oligopeptides isolated from higher plants since 1985. 

With a year production of 300-500 tons (26), the Cinchona alkaloids (quinine 1 and quinidine 2) probably form one of the largest markets of fine chemicals derived from higher plants. They are extracted from stem and rootbark of Cinchona trees, containing 5-18Z of alkaloid, with an average of about 8X (27). Because of the high demand a number of attempts have been made to develop a commercial synthesis (28 and references cited therein) of the quinoline alkaloids. Although successful syntheses have been reported they could not be commercialized. 

Natural products have a history of providing novel, clinically useful anticancer drugs and a number of these have come from higher plants (ref. 1-21). In addition, many of these compounds have served as prototypes for the development of novel analogs of clinical importance. Some specific examples are colchicine (ref. 22) and its derivatives, the podophyllotoxins (ref. 23) including the clinically-effective epipodophyllotoxin derivatives etoposide and teniposide (ref. 24), and the Vinca alkaloids, vincristine, vinblastine, and vindesine (ref. 25,26). More recently indicine N-oxide, homoharringtonine and taxol have entered clinical trials (ref. 13,21). The discovery of natural products with potential as anticancer drugs has recently been reemphasized by the NCI. 

There are probably over 25,000 alkaloids derived from higher plants as presented in the Didionary of Alkaloids. This modest volume offers a brief... 

On the other hand, alkaloids in which cinnamic acid and various phen-ylpropanoids like caffeic acid and other acids combine with polyamines as amides are also isolated from higher plants. Among them, about eighty alkaloids contain spermidine as a base, and about thirty alkaloids contain spermine as a base [5]. These alkaloids are known as polyamine alkaloids. Some representatives of these alkaloids are described in the next section. 

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