Anigozanthos

At first sight the title compounds characterized by the general formula 111, are rather unrelated to diarylheptanoids. At closer look, however, the two classes of compounds can be linked by a very plausible biosynthetic hypothesis first forwarded by Thomas (80) and shown in the following scheme below. 9-Phenylphenalenones were isolated from Haemodorum (74), Lachnates (75, 76), Xiphidium (77), Wachendoifia (78), and Anigozanthos (79) (Haemodoraceae) species. 

Anigozanthos preissii Endl. root cell culture anigopreissin A (51) dimer (C28H20O6) NA [79]... 

Dihydroxyanigorufone Anigozanthos rufus (45) red needles Conostylis setosa (47)... 

Cooke, R. G., and R. L. Thomas Colouring Matters of Australian Plants. XVIII. Constituents of Anigozanthos rufus. Austral. J. Chem. 28, 1053 (1975). 

Constit. of Anigozanthos rufus. Phytoalexin. Fine needles (Me2CO/petrol). Mp 241-243°. 

Holscher D, Schneider B (1996) A resveratrol dimer from Anigozanthos preissii and Musa cavendish. Phytochemistry 43 471-473... 

The ratio of sucrose-derived hexoses, fructose and glucose, in the floral nectar of Anigozanthos flavidus (Haemodoraceae) was observed to be different from 1 1, which cannot be explained by the simple action of inver-tases. Various NMR techniques were used to investigate how such an unbalanced ratio of the two nectar hexoses can be formed. In vivo MRI (e.g. cyclic J cross-polarization) was used to detect carbohydrates in vascular bundles and H-1 spin echo imaging non-invasively displayed the architecture of tepal nectaries and showed how they are connected to the vascular... 

Polyketides with one or two phenylpropa-noid moieties and only one carbon derived from malonyl-Co A are the raspberry aroma/>-hydroxy-phenylbutan-2-one, the curcuminoids of turmeric Curcuma), and phenylphenalenones from Musa dmd Anigozanthos species (Fig. 23). Curcuminoids and phenylphenalenones contain two phenylpropanoid moieties on both sides of the acetate-derived carbon and are therefore classified as diaryIheptanoids. These two groups of natural products are pigments due to their conjugated system of 7i-electrons. Curcuminoids are widely used as spices and also have antiinflammatory, antioxidative, and anti-cancer properties (Joe et al., 2004). 

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