Biosynthesis of anthraquinones

PL Bartel, CB Zhu, JS Lampel, DC Dosch, NC Conners, WR Strohl, JM Beale, HG Floss. Biosynthesis of anthraquinones by interspecies cloning of actinorhodin biosynthesis genes in Streptomyces. clarification of actinorhodin gene functions. J Bacteriol 172 4816-4826, 1990. 

ABSTRACT This paper attempts to present a review on the study of phytochemical and pharmacological activities of plants from the genus Hedyotis (Rubiaceae) in the last seven decades, which include our work on Malaysian Hedyotis species. The structure-activity relationships of compounds isolated from this genus are compiled and discussed. Finally, there is also a brief discussion on the biosynthesis of anthraquinones, iridoid glycosides and alkaloids, which are the common constituents of Hedyotis species. 

Han, Y.S Heidjen, R.V.D. Lefeber, A.W.M Erkelens, C Verpoorte, R. Biosynthesis of anthraquinones in cell cultures of Cinchona Robusta proceeds via the methylerythritol 4-phosphate pathway. Phytochemistry. 2002,59,45-55. 

Leistner in Germany and Burnett in Great-Britain have performed much work on the biosynthesis of anthraquinones [5,23-28]. Two different pathways for the biosynthesis of anthraquinones in plants exist either the polyketide pathway or the shikimate pathway [5], Anthraquinones synthesised according to the former pathway are substituted in both ring A and C. Examples are emodin and chrysophanol. These polyketide-derived anthraquinones are found in Rhamnaceae, Polygonaceae and Leguminosae... 

Fig. (5). Biosynthesis of anthraquinones by the shikimate pathway based on the scheme proposed by Wijnsma and Verpoorte [4]...

Biosynthesis of Anthraquinones Distribution of Anthraquinones Biological Functions of Anthraquinones Economic Importance and Uses Anthrones and Anthrone Dimers Hypericin and Antihrone Dimers References... 

Fig, 6.15. Proposed biosynthesis of anthraquinones in species of Rubiaceae (modified from Inouye and Leismer, 1988 used with permission of the copyright owner, John Wiley Sons, Ltd., Chichester). 

Anthrones e.g., emodin anthrone (12) are probable intermediates in the biosynthesis of anthraquinones such as emodin from polyketide pathways (Fig. 6.22) and occur widely in nature. The position para to the carbonyl oxygen of the center (B) ring is sensitive to oxidation and, in many instances, oxidation products may be the major or only compounds isolated from plants which contain anthraquinones after storage (Leistner, 1985). 

Inoue, K., Y. Shiobara, H. Nayeshiro, H. Inouye, G. Wilson, and M. H. Zenk, Biosynthesis of anthraquinones and related compounds in Galium mollugo cell suspension cultures. Phytochemistry, 23, 307-311 (1984). 

Bartel PL, Zhu C-b, Lampel JS, Dosch DC, Connors NC, Strohl WR, Beale JM Jr, Floss HG. Biosynthesis of anthraquinones by interspecies cloning of accinorhodin biosynthesis genes in streptomycetes Claiification of actinorhodin gene functions, j Bacteriol 1990 172 4816-4826. 

This suspension culture of Morinda cells is being studied because the biosynthesis of anthraquinones and its glycosides can be triggered in the culture. Upon transfer of cells into darkness and a medium containing sucrose the chlorophyll decreases and the lipoquinones (including phylloquinone) disappear from the cells (Table 1). Simultaneously, anthraquinone pigments are formed (Fig. 4) and the cultured cells turn yellow and eventually red. Thus, in the suspension culture photoautotrophy correlates with lipoquinone synthesis while heterotrophy correlates with anthraquinone synthesis. This reflects the situation in the intact plants where lipoquinones are associated with chloroplast whereas anthraquinones occur in the roots. 

WILSON, M.H. ZENK. 1984. Biosynthesis of anthraquinones and related compounds in Galium mollugo cell suspension cultures. Phytochemistry 23 307-311. 

Isolation, Identification and Biosynthesis of Anthraquinones in Cell Suspension Cultures of Morinda citrifolia. Planta Med. Suppl. 1975, 214. 

Gatenbeck, S. Studies on the biosynthesis of anthraquinones in lower fungi. Svensk Kem. Tidskr. 72, 188 (i960). 

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