Pyura

These are perhaps the most diverse group of aromatic alkaloids isolated from ascidians. Their structures span a range of complexity, starting with 6-bromoindole-3-aldehyde (105) (previously reported from a marine Pseudomonas sp.), and the brominat quinazolinedione (106) from Pyura sacciformis [76]. 

Endean R. 1955a. Studies of the blood and test of some Australian ascidians. II The test of Pyura stlonifera (Heller). Aust J Mar Freshw Res 6 139-156. 

Wardrop A.B. 1970. The structure and formation of test of Pyura stolonifera (Tunicate). Protoplasma 70 73-86. 

Halocynthia roretzi is consumed in Japan, and Pyura chilensis in Chile. It has recently been shown that Pyura chikr sis could be a vector of domoic acid during toxic diatom blooms (Lopez-Rivera et al., 2009). 

Lopez-Rivera, A., Pinto, M., Insinilla, A., Isla, B.S., Uribe, E., Alvarez, G., Lehane, M., Furey, A., and James, K.J. (2009) The occurrence of domoic acid linked to a toxic bloom in a new potential vector the tunicate Pyura chilensis (piure). Toxicon, 54, 754—762. 

In the order Stolidobranchia, the two families Molgulidae and Pyuridae have led to a limited number of publications on their metabolites. Most published work on Molgulidae concerns the tunichromes of Molgida manhattensis (see above). For Pyuridae, the current works concern mainly the four genera Cynthia, Halocynthia, Pyura and Microcosmus, but the overall picture remains fragmented. 

Among alkaloids, a derivative of quinazoline and an antifungal and antibacterial chloroindole have been found in Pyura sacdformis and Cynthia savignyi. 

Liebrich, W, Brown, A.C., and Botes, D.P. (1995) Cadmium-binding proteins from a tunicate, Pyura stdonfrra. Comp. Biochem. Physiol., me. iS-42. 

Niwa, H., Yoshida, Y, and Yamada, K. (1988) A brominated quinazolinedione from the marine tunicate Pyura sacdfcarmis. J. Nat. Prod., 51, 343-344. 

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