Soft Corals Biodiversity in the Egyptian Red Sea: A Comparative MS and NMR Metabolomics Approach of Wild and Aquarium Grown Species

Abstract

Marine life has developed unique metabolic and physiologic capabilities and advanced symbiotic relationships to survive in the varied and complex marine ecosystems. Herein, metabolite composition of the soft coral genus Sarcophyton was profiled with respect to its species and different habitats along the coastal Egyptian Red Sea via (1)H NMR and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) large-scale metabolomics analyses. The current study extends the application of comparative secondary metabolite profiling from plants to corals revealing for metabolite compositional differences among its species via a comparative MS and NMR approach. This was applied for the first time to investigate the metabolism of 16 Sarcophyton species in the context of their genetic diversity or growth habitat. Under optimized conditions, we were able to simultaneously identify 120 metabolites including 65 diterpenes, 8 sesquiterpenes, 18 sterols, and 15 oxylipids. Principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS) were used to define both similarities and differences among samples. For a compound based classification of coral species, UPLC-MS was found to be more effective than NMR. The main differentiations emanate from cembranoids and oxylipids. The specific metabolites that contribute to discrimination between soft corals of S. ehrenbergi from the three different growing habitats also belonged to cembrane type diterpenes, with aquarium S. ehrenbergi corals being less enriched in cembranoids compared to sea corals. PCA using either NMR or UPLC-MS data sets was found equally effective in predicting the species origin of unknown Sarcophyton. Cyclopropane containing sterols observed in abundance in corals may act as cellular membrane protectant against the action of coral toxins, that is, cembranoids.

Recent Advances in NMR-Based Metabolomics

“…91 A total of 120 metabolites including 65 diterpenes, 8 sesquiterpenes, 18 sterols, and 15 oxylipids were identified. A number of these contributed to the differentiation of species and their unique habitats.…”

Cembranoids of Soft Coral Sarcophyton from Acidified Coral Reef Environment at Shallow Water CO2 vents in Volcano Island, Banda Neira, Indonesia

“…The content of cembranoid is highly dependent upon environmental factors, as the ecological relationship with the number of predators and spatial competitors (Slattery, Starmer, & Paul, 2001). Soft coral that was taken from natural coral reefs was detected to contain diverse cembranoid compounds than cultivated aquariums (Farag et al, 2016). Our previous finding also showed cembranoid was produced in higher concentration at healthier coral reef environment (Januar, Hendrarto, Chasanah, & Wright, 2011;Januar, Marraskuranto, Patantis, & Chasanah, 2012;Januar et al, 2015).…”

“…Meanwhile, cembranoid content also depends on the genetic diversity of soft coral. Previous studies on Sarcophyton glaucum found that each genetic clade (Clade A to F) contains a combination of 8 cembranoid chemotypes (Aratake et al, 2012;Farag et al, 2016). Furthermore, multivariate statistics for cembranoid quantity was successfully validated to be a profiling taxonomic approach between soft coral Lobophytum, Sinularia, and Sarcophyton (Farag et al, 2017).…”

Metabolomics reveals biotic and abiotic elicitor effects on the soft coral Sarcophyton ehrenbergi terpenoid content

“…Examination of the loading plot indicated that the distant clustering of ZnCl 2 and SA elicited coral samples was almost exclusively due to mass signals m/z 361, 383 and 743 eluted at retention time ( R t ) 5.32 corresponding to sarcophytonolide I and assigned as [M + H] + , [M + Na] + and [2 M + Na] + , respectively. Details on metabolites identification strategy has previously been published 38 . Hierarchical cluster analysis, similar to PCA, is an unsupervised data analysis method that establishes relationships among similar groups of samples allowing for analysis of the results in a fairly easier way.…”

“…Although different Sarcophyton species were subjected to extensive chemical and biological studies 38 , to our knowledge there are no reports regarding the chemical composition of the corals in response to elicitation using large scale untargeted analytical techniques. Metabolomics, defined as the comprehensive profiling of all metabolites within a given sample in a particular physiological state, provide a holistic measure of the global changes occurring post elicitation.…”