Botanical Distribution

The first flavonoidal alkaloids to be isolated were ficine (4) and isoficine (5) in 1965 from Ficus pantoniana King. (Moraceae) (i). These alkaloids have not 

Most recently a series of piperidinyl-flavonoid alkaloids have been isolated from two Buchenavia spp. (Combretaceae) (6). The leaves of B. macrophylla Eichl. yielded buchenavianine (8) and iV-demethylbuchenavianine (9). The fruits 

IV-demethylcapitavine (12), and 5,7-dihydroxy-6-(iV-methyl-2 -piperidinyl)fla-vanone (13). The seeds of B. capitata Eichl. were found to contain three other such alkaloids. These were named capitavine (14), 5,7,4 -trihydroxy-6-(N-meth- 

13 (R = H) 5,7-Dihydroxy-6-(A -methyl-2 -piperidinyl)flavanone 16 (R = OH) 5,7,4 -Trihydroxy-6-(Af-methyl-2 -piperidinyl)flavanone 

The flavonoidal alkaloids have thus been found widely scattered throughout the higher plants. In view of the ubiquitous occurrence of flavonoids and the simplicity of the nitrogenous component in the compounds so far isolated, it is quite possible that they may occur in more species. The occurrence of the flavonoid alkaloids in Buchenavia but not Terminalia has been used to confirm the taxonomic distinction between these genera (6). 

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Owing to the frequency with which the botanical attribution of ipecacuanha has been changed, and to the considerable number of substitutes which have from time to time appeared, it is difficult to summarise briefly the botanical distribution of the ipecacuanha alkaloids, and readers interested in this subject may be referred to Staub for information and references. Freise states that emetine and the allied bases are to be found in certain Rubiaceous spp. not usually regarded as sources of these alkaloids, and Orazi has stated that the roots of Bourreria... 

Xylan occurs in practically all land plants and is said to be present in some marine algae.6 In both wide botanical distribution and abundance in nature it closely follows cellulose and starch. It is most abundant in annual crops, particularly in agricultural residues such as corn cobs, corn stalks, grain hulls and stems. Here it occurs in amounts ranging from 15 to 30%. Hard woods contain 20 to 25% xylan while soft woods contain 7 to 12 %. Spring wood has more pentosan than summer wood. 7 Low strength vegetable fibers of commerce such as jute, sisal, Manila... 

Jaroszewski JW, Strom-Hansen T, Hansen SH, Thastrup O and Kofod H (1992) On the botanical distribution of chiral forms of gossypol. Planta Med 58, 454-458. 

Cyclopentanes, including Iridoids.—A summary of the botanical distribution, structure, and properties of the iridoids and seco-iridoids has been compiled, including about 80 natural products. "... 

Volume 14 of this series presents three interesting reviews of research on alkaloids. Chapter I, by Paul L. Schiff, Jr. is a monumental effort, presenting a selective, comprehensive tabular review of research on the bisbenzylisoquinoline alkaloids, with an analysis of the respective alkaloid types. The chapter should serve as a very useful tool for the bench research scientist who is involved in the isolation and elucidation of structures of bisbenzylisoquinoline alkaloids. Moreover, the data in these tables provides the botanical distribution and occurrence (family, genus, species) of the various classes of these alkaloids. The alkaloids are also categorized by their molecular weights and structural types. 

For some time now several research laboratories have been intensively researching this family, inspired by its broad and varied botanical distribution, the interesting chemical nature of its secondary metabolites, the complexity of the biogenetic processes which produce diem, and most of all by the different types of pharmacological action displayed by preparations of its constituents. In Latin America (Mexico, Central America, the Caribbean and South America) this study is particularly momentous due in the main to a socio-economic and cultural climate which has not in the past lent itself either to sound development or the rational exploitation of the resources of the various countries involved. 

In the last group alone, there are more than 160 members, some of which are toxic. Many other alkaloids, some of great complexity, can be found in plants and frequently are referred to by the plant name. Thus, the Amaryllidaceae (exemplified by the common narcissus plant) alkaloids are a rich collection of complex stmctures. From the moss family Lycopodiaceae are obtained a group known as the Lycopodium alkaloids. Many miscellaneous alkaloids also are known. The book by Aniszewski is an excellent source of information on other types of alkaloids, their botanical distribution, and their biological and other features. 

I. include isoflavones, isoflavanones, isoflavans, iso-flav-3-enes, rotenoids, pterocarpans, coumestans, 3-aryl-4-hydroxycoumarins, 2 -hydroxy-3-arylcoumar-ins, 2-arylbenzofurans, a-methyldeoxybenzoins and individual compounds like lisetin and ambanol (see separate entries). I. have a restricted botanical distribution, occurring chiefty in the subfamily Papilionoi-deae of the Leguminoseae, and sometimes in the subfamily Caesalpinioideae. Their occasional presence in other families has also been reported (Rosaceae, Mor-aceae, Amaranthaceae, Podocarpaceae, Chenopodia-ceae, Cupressaceae, Iridaceae, Myristicaceae, Stemo-naceae). I. have also been reported from microbial cultures (e.g. T.Hazato et al. J.Antibiot. Tokyo 32 (1979) 217-222), but in all cases the culture media contained soybean meal, so the possibility remains that these 1. are of plant origin. 

Among the questions which arise when considering absolute configuration of coumarins in relation to biosynthesis are Do the changes in absolute configuration correlate with the nature of the chemical transformations in the various steps of coumarin biosynthesis Does the absolute configuration of oxidized isopentenyl substituted coumarins correlate with their botanical distribution Is there a simple biosynthetic model which can accommodate the occurrence of the different coumarin enantiomers as well as racemates ... 

In the following sections, the plants and their alkaloid contents are presented according to their botanical distribution. 

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