Institute of Applied Science

IAS




Master of Science: Semisi Meo

Semisi Meo


    

Degree: Master of Science in Chemistry

Researcher: Semisi Meo

Thesis title: The study of natural products from sponge Jaspis coriacea and a new Fijian ascidian Polyandrocarpa species.

Supervisor: Prof. William Aalbersberg

Thesis Abstract:

 

An investigation of the chemistry of the Fiji marine invertebrates yielded new natural products and interesting changes in the production of the metabolites.

Chemical investigation of a new Fijian War Club marine ascidian Polyandrocarpa sp has resulted in the isolation of two new 2-aminoimidazolone derived compounds, polyandrocarpamine A (97) and polyandrocarpamine B (108). The structures of these unique metabolites were determined by interpretation of spectroscopic data. The natural products were assigned Z geometries about the exocyclic double bond (C-5/C-7) on the basis of 13C/1H long-range coupling constants, which were measured using a gHSQMBC experiment.

Investigation into the bengamide ratio mix in the sponge Jaspis coriacea collected from Suva Harbor, Fiji showed some degree of variation at different times of the year. There were some contradicting results obtained from this study as compared to previous collections of the same sponge in Fiji. A consistency in bengamide mix was evident in the warmer month collection (November and February) and greater variation in bengamide mix occured during the cooler month collection (May and August). The mechanism behind changes in bengamide ratio mix it either influenced environmentally or genetically cannot be determined by the data. Samples examined showed presence of extra isomeric bengamide compounds which signifies that there still are some bengamide variants to be elucidated and characterized.

1 of 2 research sites: Fish patch and Dennis patch on Suva reef.

(97) Polyandrocarpamine A

Semisi at his research site.   

 The sponge, Jaspis coriacea.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



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