Search

Amphidinolides C, F, and U, including C2‐C4 analogs, are highly cytotoxic marine macrolides, mainly isolated from dinoflagellates of the genus Amphidinium. All these polyketides share a 75 % or more similar structure, highlighted by a macrolactone ring, at least one trans‐2,5‐substituted‐THF motif and a characteristic polyenic side chain. From their isolation and absolute configurational assignment, the total synthesis of these marine macrolides represented an intense challenge to the organic synthesis community over the last 15 years, with around 14 research groups engaged in this inspiring task. In the first part of this review, we present the different approaches to the isolation and characterization of these natural products, including the most recent analogs, which may cast doubt on the biogenetic origin of these compounds. The various synthetic approaches to the total synthesis of C, F, and U amphidinolides are presented in a second part, focusing on key reactions and/or innovative strategies. The review concludes in a third section summarizing the successful approaches leading to the total synthesis of one of the members of this amphidinolide subfamily. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the chemical composition and antimicrobial and antioxidant activities of the essential oil from dried seeds of Xylopia aethiopica. The essential oil was obtained by hydrodistillation and analyzed by GC/FID and GC/MS. The essential oil yield was 1.35%. Forty-nine compounds were identified in the essential oil with 1,8-cineole (16.3%), β-pinene (14.8%), trans-pinocarveol (9.1%), myrtenol (8.3%), α-pinene (5.9%), and terpinen-4-ol (5.6%) as major components. The antimicrobial activity of this essential oil was studied using disk diffusion and broth microdilution methods on four bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) and one fungus (Candida albicans). The essential oil exhibited excellent activity against S. aureus, E. faecalis, and C. albicans and moderate activity against E. coli. Among all strains tested, C. albicans showed the best sensitivity with a MIC of 50 mg/mL. The antioxidant activity was examined using a DPPH-free radical scavenging assay. The essential oil of X. aethiopica showed low antioxidant activity (IC50 = 784.604 ± 0.320 mg/mL) compared to that of ascorbic acid and the reference compound (IC50 = 0.163 ± 0.003 mg/mL). The results indicate that consumption of X. aethiopica seeds can reduce the virulence of food-borne pathogens and their resistance to antibiotics. [ABSTRACT FROM AUTHOR]

Keywords: amphidinolides; polyketides; total synthesis; Suzuki cross-coupling; epoxides; protecting groups EN amphidinolides polyketides total synthesis Suzuki cross-coupling epoxides protecting groups 2017 2021 5 10/09/23 20231024 NES 231024 Graph Amphidinolide U is a moderately cytotoxic macrolide isolated from dinoflagellates of an I Amphidinium i species, with reported IC SB 50 sb values on L1210 and KB cell lines of 12 and 20 g/mL, respectively. 1994, 107 24 Ley, S V. Tackett, M N. Maddess, M L. Anderson, J C. Brennan, P E. Cappi, M W. Heer, J P. Helgen, C. Kori, M. Kouklovsky, C. Marsden, S P. Norman, J. Osborn, D P. Palomero, M. Á. Pavey, J B. J. Pinel, C. Robinson, L A. Schnaubelt, J. Scott, J S. Spilling, C D. Watanabe, H. Wesson, K E. Willis, M C. Chem. Eur. J. 2009, 15: 2874 25 Cid, M B. Pattenden, G. Synlett. Chem. 2006, 71: 5826 20 Mihelich, E D. Daniels, K. Eickhoff, D J. J. Am. Chem. Soc. 1981, 103: 7690 21 Corey, E J. Fuchs, P L. Tetrahedron Lett. Int. Ed. 2001, 40: 4544 29 Berthold, D. Breit, B. Chem. Eur. J. 2018, 24: 16770 30 Geist, E. Kirschning, A. Schmidt, T. Nat. [Extracted from the article]