Chemometric methods have provided an efficient and powerful tool for the quality control and authentication of different herbs.

Reinvestigation of the Red Sea sponge Suberea mollis afforded two new bromotyrosine-derived alkaloids, subereamollines A (1) and B (2), two new brominated phenolic compounds, subereaphenols B (7) and C (9), and the known compounds aerothionin (3), homoaerothionin (4), 11,19-dideoxyfistularin-3 (5), aeroplysinin-1 (6), and aeroplysinin-2 (8). The structure determination of the isolated compounds was assigned using one- and two-dimensional NMR spectra and HRFABMS data. The antimicrobial and antioxidant activities of the isolated compounds have been evaluated. Aeroplysinin-1 displayed significant antimicrobial activity against S. aureus, P. aerugenosa, and K. pneumoniae. The isolated compounds were examined for their antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay. Among the tested compounds, only subereaphenols B and C displayed a significant effect.

This work describes a simple model developed for the authentication of monofloral Yemeni Sidr honey using UV spectroscopy together with chemometric techniques of hierarchical cluster analysis (HCA), principal component analysis (PCA), and soft independent modeling of class analogy (SIMCA). The model was constructed using 13 genuine Sidr honey samples and challenged with 25 honey samples of different botanical origins. HCA and PCA were successfully able to present a preliminary clustering pattern to segregate the genuine Sidr samples from the lower priced local polyfloral and non-Sidr samples. The SIMCA model presented a clear demarcation of the samples and was used to identify genuine Sidr honey samples as well as detect admixture with lower priced polyfloral honey by detection limits >10%. The constructed model presents a simple and efficient method of analysis and may serve as a basis for the authentication of other honey types worldwide.

Chemical investigation of the Red Sea sponge Pseudoceratina arabica has led to the isolation and identification of seven brominated compounds including two new bromotyramine derivatives, hydroxymoloka'iamine (2) and moloka'iakitamide (6), and a new brominated phenolic compound, ceratinophenol A (5), together with the known compounds moloka'iamine (1), ceratinamine (3), 5-bromo-2,3-dihydroxy-6-methoxybenzaldehyde (4), and psammaplysin-A (7). Biological evaluation of these metabolites indicated that moloka'iamine and moloka'iakitamide possess significant parasympatholytic effects on isolated rabbit heart and jejunum. This finding has important implications for further biological investigation of this class of compounds. Moreover, these compounds showed weak antibacterial and antifungal activities.