Rhodymenia palmata

Unlike the xylans already discussed, Rhodymenia palmata /3-D-xylan contains mixed (l- 3) and (l- 4) linkages. On reaction with a cellulase that had /S-D-xylanase activity,74 a series of (l- 4) and mixed-linkage xylosaccharides was produced that included (1 - 4)-0-xylo-biose, -triose, -tetraose, and a mixed-linkage trisaccharide, namely, 32-0-/3-D-xylosyl-xylobiose (17). endo-(l - 4)-/3-D-Xylanase has been shown62 to catalyze... 

Barry and Dillon184 prepared a polysaccharide from the red seaweed Rhodymenia palmata by extracting the plant with dilute hydrochloric acid and precipitating the product with alcohol. This substance gave... 

B. H. Howard, Hydrolysis of the soluble pentosans of wheat flour and Rhodymenia palmata by ruminal micro-organisms, Biochem. J., 67 (1957) 643—651. 

H. Bjomdal, K. E. Eriksson, P. J. Garegg, B. Lindberg, and B. Swan, Studies on the xylan from the red seaweed Rhodymenia palmata, Acta Chem. Scand., 19 (1965) 2309-2315. 

Rhodymenia palmata or Irish Dulse is a purplish-red, flat, membranous, palmately cleft or dichdtomous red alga growing on the tissues of other algse along northern shores of the Atlantic between the low- and high-tide marks. 

Porphyra laciniata (Lightfoot) Agardh. Rhodymenia palmata (L.) Greville... 

The marine algal D-xylan obtained from Rhodymenia palmata has been shown250-251 to be composed of /3-d-(1 — 3)- and /3-D-(l — 4)-linked D-xylose residues in a single D-xylan chain, and it is suscep-... 

Structures of Xylo-oligosaccharides Isolated from Enzymic Hydrolyzates of Rhodymenia palmata D-Xylan... 

This starch differs in that no amylose is present, but it resembles amylopectins in many of its properties. There is little evidence for starch in oAer red algae [e.g., Rhodymenia palmata (dulse)]. In this alga, the major polysaccharide is a water-soluble xylan made up of random 1,3-and 1,4-linked units. Other 1,3-, 1,4-, and mixed 1,3- and 1,4-xylans have been isolated from a number of red algae (Percival, 1970, 1979). 

C15H26O13 414.363 Constit. of the cell walls of Penicillus dumetosus, Rhodymenia palmata and several other green algae. 

Isol. from a partial enzymatic hydrolysate of the seaweed polysaccharide rhodyme-nan from Rhodymenia palmata. 

A xylan from esparto grass 63, 64) is a singly branched chain of about 76 D-xylopyranose units linked jS-D-1— 4 in the main chain but with a 1—>3 link at the point of branching. From the cell wall of pear wood, another similarly single-branched xylan is obtained which has about 115 D-xylo-pyranose units, but it contains, in addition, a terminal D-glucopyranosyl-uronic acid unit at one point 65), The xylan from the red seaweed 57,58) Rhodymenia palmata seems to be composed only of D-xylopyranose units... 

True xylans have been found in algae. The xylan from the red seaweed Rhodymenia palmata contains 80% of u-(i -> 4) links and 20% of fi-v-(i - 3) links, while the green seaweed Caulerpa filiformis contains a xylan with only p-v-(i -> 3) links. 

The species Rhodymenia palmata is consumed imder the name dulse because it is rich in protein (about 40% of dry weight) and vitamins however, apart from the oxy-lipins mentioned earlier, there are very few publications on the secondary metabolites of Rhodymeniales. Among these, the identification of 3-formylindole in the species Botryodadia leptopoda is noteworthy because this derivative could come from /5-indole acetic add (lAA, auxin), an important plant growth hormone (Bano et al., 1986). More recently, p-sulfo-oxyphenylpyruvic add has been identified in Ceratodictyon spongiosum harvested in the Philippines. This acid, which exists mainly in the enolic form, is isolated mixed with p-hydroxyphenylpyruvic add (Bugni et al, 2002). 

No halogenated terpene has yet been found in a Rho-dymeniale, but the presence of iodinated derivatives of tyrosine in Rhodymenia palmata (mono- and diiodotyro-sine, thyroxine) has been known for more than 50 years (Scott, 1954). 

Idler, D.R. and Wiseman, P. (1970) Sterols in red algae (Rhodophyceae) variation in the desmosterol content of dulse (Rhodymenia palmata). Comp. Biochem. Physiol. 35,679-687. 

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