Metabolomic profiling and biological investigation of the marine sponge-derived bacterium Rhodococcus sp. UA13.

INTRODUCTION: Marine sponge-associated actinomycetes are potent sources of bioactive natural products of pharmaceutical significance. They also contributed to the discovery of several clinically relevant antimicrobials. OBJECTIVE: To apply the non-targeted metabolomics approach in chemical profiling of the sponge-derived bacterium Rhodococcus sp. UA13, formerly recovered from the Red Sea sponge Callyspongia aff. Implexa, along with testing for the anti-infective potential of its different fractions. METHODOLOGY: Metabolomic analysis of the crude extract was carried out using liquid chromatography with high resolution electrospray ionisation mass spectrometry (LC-HR-ESI-MS) for dereplication purposes. Besides, the three major fractions (ethyl acetate, methanol, and n-butanol) obtained by chromatographic fractionation of the crude extract were evaluated for their anti-infective properties. RESULTS: A variety of metabolites, mostly peptides, were characterised herein for the first time from the genus Rhodococcus. Among the tested samples, the n-butanol fraction showed potent inhibitory activities against Staphylococcus aureus, Candida albicans, and Trypanosoma brucei brucei with IC50 values of 9.3, 6.7, and 8.7 µg/mL, respectively, whereas only the ethyl acetate fraction was active against Chlamydia trachomatis (IC50  = 18.9 µg/mL). In contrast, both fractions did not exert anti-infective actions against Enterococcus faecalis and Leishmania major, whereas the methanol fraction was totally inactive against all the tested organisms. CONCLUSION: This study showed the helpfulness of the established procedure in metabolic profiling of marine actinomycetes using liquid chromatography mass spectrometry (LC-MS) data, which aids in reducing the complex isolation steps during their chemical characterisation. The anti-infective spectrum of their metabolites is also interestingly relevant to future drug development.

Bombacaceae: a phytochemical review.

CONTEXT: Bombacaceae is a small family of the order Malvales and contains about 28 genera and 200 species. Members of this family are not only showy ornamentals but they possess significant economical and commercial reputation as well. In addition, various plant parts of several species are widely used as foods and traditional medicines in many parts of the world. OBJECTIVE: Chemical analyses of Bombacaceae species have recently yielded a number of important phytocompounds belonging to different classes. Hence, this work represents a comprehensive appraisal of the phytochemical studies conducted on Bombacaceae plants. MATERIALS AND METHODS: Searches were conducted using electronic databases (e.g., Medline, Pubmed, Academic Journals, and Springer Link); general web searches were also undertaken using Google applying some related search terms "e.g., Bombacaceae, phytochemical studies of Bombacaeae plants, and chemical investigation of Bombacaeae", journals and scientific theses. The bibliographies of papers relating to the review subject were also searched for further relevant references. RESULTS: Chemical investigations were concentrated primarily on certain species leaving fertile fields for further phytopharmacological research. CONCLUSION: The reviewed findings present Bombacaceae species as an untapped reservoir of phytocompounds which may play a supportive role in the pharmaceutical field and will be of high chemotaxonomic value within this recently separated family.