Microbial alkaloids

Keywords Alkaloid Microbial transformation Biotransformation Cinchona ... 

Enzymatic transformation of alkaloids, microbial and in vitro, 18, 323 (1981) Ephreda bases, 3, 339 (1953)... 

Experimental procedures have been described in which the desired reactions have been carried out either by whole microbial cells or by enzymes (1—3). These involve carbohydrates (qv) (4,5) steroids (qv), sterols, and bile acids (6—11) nonsteroid cycHc compounds (12) ahcycHc and alkane hydroxylations (13—16) alkaloids (7,17,18) various pharmaceuticals (qv) (19—21), including antibiotics (19—24) and miscellaneous natural products (25—27). Reviews of the microbial oxidation of aUphatic and aromatic hydrocarbons (qv) (28), monoterpenes (29,30), pesticides (qv) (31,32), lignin (qv) (33,34), flavors and fragrances (35), and other organic molecules (8,12,36,37) have been pubflshed (see Enzyp applications, industrial Enzyt s in organic synthesis Elavors AND spices). 

Biotransformations are carried out by either whole cells (microbial, plant, or animal) or by isolated enzymes. Both methods have advantages and disadvantages. In general, multistep transformations, such as hydroxylations of steroids, or the synthesis of amino acids, riboflavin, vitamins, and alkaloids that require the presence of several enzymes and cofactors are carried out by whole cells. Simple one- or two-step transformations, on the other hand, are usually carried out by isolated enzymes. Compared to fermentations, enzymatic reactions have a number of advantages including simple instmmentation reduced side reactions, easy control, and product isolation. 

H. lizuka and A. Naito, Microbial Transformation of Steroids and Alkaloids, University Park Press, State College, Pa., 1967. 

Some of the potential uses of the fats and oils found in plants have been reviewed and some uses of carbohydrate-based polymers briefly discussed. Plants contain a whole variety of other chemicals including amino acids, terpenes, flavonoids, alkaloids, etc. When the potential for these naturally occurring materials are combined with the secondary products that can be obtained by fermentation or other microbial processes or by traditional chemical transformations, the array of chemicals that can readily be created from renewable resources is huge. In this section a few of the more interesting examples are considered. 

Abstract Alkaloids are very much important molecules, not only for chemical reasons but also because of their diverse biological activities. Up to now several reviews have been published explaining the use of biotransformation or microbial transformation techniques to modify alkaloids, which added several advantages over the classical chemical transformation systems. This chapter is a critical update of the microbial transformations reported in the last couple of years, targeting novel biocatalysts from microbes. 

Fig.l Molecular structures of some alkaloids that have been used and reported in microbial transformations in the last few years... 

This review presents a critical analysis of recent updates of the research work that has been reported in last couple of years in the fields of microbial transformation or biotransformation using microbes to modify alkaloids. 

Table 1 shows examples of some of the microorganisms involved in different biotransformation processes [11]. The following sections cite some more recent examples of microbial transformation of biologically important compounds, especially alkaloids and nitrogen-containing compounds. 

Cinchona alkaloids have been used as drugs for the treatment of several diseases. Quinine is very popular as an antimalarial drug against the erythrocyte stage of the parasite [34]. Recently, Shibuya et al. (2003) reported the microbial transformation of four Cinchona alkaloids (quinine, quini-dine, cinchonidine, and cinchonine) by endophytic fungi isolated from Cin-... 

Rathbone DA, Bruce NC (2002) Microbial transformation of alkaloids. Curr Opin Microbiol 5(3) 274-281... 

Izuka H, Naito A (1981) Microbial conversion of steroids and alkaloids. University of Tokyo Press/Springer, Berlin... 

Hartman RE et al. (1964) Microbial hydroxylation of indole alkaloids. Appl Microbiol 12 138-140... 

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