Ficine

Soya Proteins. Early attempts to make albumen substitutes from soya protein also ran into problems. A bean flavour tended to appear in the finished product. A solution to these problems has been found. Whipping agents based on enzyme modified soy proteins are now available. The advantage of enzymatic modification is that by appropriate choice of enzymes the protein can be modified in a very controlled way. Chemical treatment would be far less specific. In making these materials the manufacturer has control of the substrate and the enzyme, allowing the final product to be almost made to order. The substrates used are oil-free soy flakes or flour or soy protein concentrate or isolate. The enzymes to use are chosen from a combination of pepsin, papain, ficin, trypsin or bacterial proteases. The substrate will be treated with one or more enzymes under carefully controlled conditions. The finished product is then spray dried. 

We have chosen to classify the new bases according to their sources and that often has led to homogeneous subsets. To gain concision, we have treated the similar structures of ficine, vochysine, and phyllospadine in the same section even though the Moraceae, Vochysiaceae, and Zosteraceae are unrelated. 

Although unrelated, these three families are the source of unique alkaloids that share common features. They are ficine (61) and isoficine (62) from Ficus pantoniana King (Moraceae) (107), vochysine (63) from the fruit of Vochysia guianensis (Aubl.) Poir. (Vochysiaceae) (108), and phyllospadine (64) from the seaweed Phyllospadix iwatensis Makino (Zosteraceae) (109). 

Although no experiment has yet been reported to support the idea, it seems clear that a majority of the pyrrolidine alkaloids arise from the ornithine, pu-trescine, and proline pool. This could be the case for ficine (61) and isoficine (62), vochysine (63), and phyllospadine (64) but also of the Darlingia alkaloids, which share common features with hygrine this assertion probably also holds for the ruspolinone (25) and odorine-roxburghlin (59) families. Peripentadenine, isolated from a plant of the family Elaeocarpaceae, bears resemblance to other alkaloids of the elaeocarpus type such as isoelaeocarpicine (124) (161). It cannot be excluded, however, that spermidine may be a biosynthetic intermediate instead of putrescine. The question of the origin of ant alkaloid substances remains so far without an obvious answer. 

The syntheses of flavanoid alkaloids also rest on A-l-pyrroline chemistry and on Friedel-Crafts-type reactions. In Govindachari s pioneering synthesis of ficine (167), pyrrolidine 126 is formed by condensation of trimethoxybenzene and y-aminobutyric acid in the presence of PPA (Scheme 19). Although the mechanism of this reaction has not been precisely determined, it may involve a A-l-pyrrolinium cation. These conditions were later used by Koch et al. in their synthesis of vochysine (Scheme 20) (108). 

Taschini, P. and MacDonald, D. (1987) Protease digestion step in immunohistochemical procedures ficin as a substitute for trypsin. Lab. Med. 18, 532-536. 

Plant Proteases. These include the well known proteases papain, bromelain and ficin. Most plant enzymes are available as comparatively unpurified powder extracts, although papain is notable for being available in a stabilized and purified liquid form. Prospects for increased supply of plant enzymes, in response to greater use in traditional applications or for new processes, depend on several factors. Tlie influence of cultivation conditions, growth cycle and climate requirements make new supplies long term projects. 

The greatest variety of industrial enzymes are presently derived from microbial sources, with a lesser diversity coming from plant and animal sources 34), Enzymes derived from plant sources and which are used extensively in the food industry include papain, bromelain, ficin, and amylases. Animal enzymes of economic importance include trypsins, lipases, and gastric proteases. 

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... 

Details of the extraction methods for ficine (4) and isoficine (5) were not given. Phyllospadine (6) was isolated from the flavonoid-containing n-butanol-soluble extract from dried plant material (4). The alkaloids from Vochysia and Buchenavia were isolated by conventional procedures, utilizing acid-base extraction and subsequent column or thin-layer chromatography using silica gel or alumina (5,6). 

The fiavonoidal moiety of ficine was deduced from its UV spectrum, which was very similar to chrysin (37), and the bathochromic shift indicated a saturated alkyl substituent on ring A. Treatment with Gibb s reagent to detect the presence of a proton para to a phenolic OH (17) gave a positive result for 5 but not 4. Although no molecular ion could be seen in the mass spectrum, the peaks obtained were equivalent to the sum of the individual spectra of chrysin (37) and... 

A -methylpyrrole. It was assumed that pyrolysis occurred at the inlet temperature and that ficine and isoficine consisted of chrysin substituted with M-methylpyr-role at positions 8 and 6, respectively. The presence of chrysin as part of the molecule was confirmed by its formation from 4 by alkaline hydrolysis. 

Cleavage of ficine (4) to yield the parent flavonoid has been achieved, using pyrolysis or mild alkali in methanol (5). Vochysine (7) has been cleaved in the presence of alcohol to give the parent flavan (7). The nitrogenous part of the molecule cannot be detected after cleavage as it breaks down under alkaline conditions. 

Interconversion of ficine (4) and isoficine (5) has been carried out by refluxing in 70% HCl (3). The mechanism involved was thought to be due to a Wessely-Moser rearrangement. 

Proteins free-sulfvdrvl ficin (MW 23,88-25,000, from Ficus spp., Moraceae, Ang. MI). 

Additional examples of type d (Scheme 5.1) bifunctional reactants are provided by the alkaline-earth metal ion complexes of lariat ethers 8-10, bearing a sulfhydryl side arm, instead ofthe phenolic hydroxyl of a calixcrown [23,24]. Here the acyl-receiving and acyl-releasing unit, like in papain and ficin, is a sulfhydryl group. 

In the course of investigations using 4-chloro-7-nitrobenzofurazan as a reactivity probe for identifying the active sites of a number of enzymes such as papain, ficin, and bromelain, the intermediacy of Meisenheimer adducts derived from direct attack of thiolate groups located in the protein has been assumed on the basis of the spectral changes accompanying the process of replacement of the chloro group.232,233... 

---