Alkaloids from the Tunicate Polycarpa aurata from Chuuk Atoll

Abstract

Two new alkaloids, polycarpine (1) and N,N-didesmethylgrossularine-1 (4), have been isolated from extracts of the ascidian Polycarpa aurata collected in Chuuk, Federated States of Micronesia. Three degradation products of 1 were also isolated. The structures of 1, 2, and 4 were determined by X-ray crystallography. The dimeric disulfide 1 inhibited the enzyme inosine monophosphate dehydrogenase, but the inhibition could be reversed by addition of excess dithiothreitol suggesting that 1 reacts with sulfhydryl groups on the enzyme.

Synthesis and Antibacterial Activity of Bis[2-amino-4-phenyl-5-thiazolyl] Disulfides

“…6,7) A large number of compounds having disulfide linkage have been isolated from different plants and animals. Among these, polycarpine dimeric disulfides were the first to be isolated as unusual bioactive secondary metabolites from marine ascidians (urochordates), 8,9) having 2-aminoimidazole rings linked by disulfide bridges 10) (Fig. 1).…”

Structure of Thioviridamide, a Novel Apoptosis Inducer from Streptomyces olivoviridis

“…Thioamide-containing natural products, (4-methoxyphenyl)-N-methyl-2-oxothioacetamide [6] and cycasthioamide [7] have been isolated from a tunicate Polycarpa aurata and a cycad Cycas revoluta, respectively. Each of these compounds, however, contains only one thioamide group.…”

Synthesis of thieno- and benzocyclohepta[b]indoles: Gewald reaction and regioselective cycloaddition of acetylenic esters

“…[1][2][3][4][5][6] The antidepressant activity of cyclohepta[b]indole 7 has stimulated considerable interest and had been the starting point for the synthesis of a large number of polycyclic indole derivaties. [8][9][10] Alkaloids that feature an indole nucleus such as prenylated indoles, carbazoles, indoloquinoline and cyclohepta [b]indole alkaloids often exhibit biological activities such as e.g.…”

“…15,16 In this class of compounds a heteroaromatic ring is fused to the side [b] of the carbazole ring. However, there is a growing number of cyclohepta [b]indoles that contain aromatic or heteroaromatic rings fused to the [6,7]-or [4,5] side of the cyclohepta [b]indoles nucleus. For example, among the various benzo cyclohepta [b]indoles, a series of simple benzo [6,7]cyclohepta [b]indoles and benzo [5,6]cyclohepta [b]indoles such as 2 or 3, have been tested as candidates for the treatment of cytotoxicity and CDK inhibitory Figure 1.…”

“…For example, among the various benzo cyclohepta [b]indoles, a series of simple benzo [6,7]cyclohepta [b]indoles and benzo [5,6]cyclohepta [b]indoles such as 2 or 3, have been tested as candidates for the treatment of cytotoxicity and CDK inhibitory Figure 1. Examples of (1): ellipticine; (2): of a benzo [6,7]cyclohepta [b]indole; (3): a benzo [5,6]cyclohepta [b]indole; (4) a benzo [4,5]cyclohepta [b]indole.…”