Radames J. Álvarez-Zapata’s research while affiliated with Autonomous University of Campeche and other places

The influence of silver nanoparticles (AgNPs) on microbial biofilm colonization on natural calcareous rocks was studied in the Campeche marine intertidal environment in southeast Mexico. The biofilm formation was assessed by color spectrophotometer measurements represented in the CIELAB color space, digital image analysis, confocal laser scanning microscopy, biochemical biomarkers, and enumeration of morphologically characterized cells by FlowCAM®. Coupons were exposed with or without polydimethylsiloxane (PDMS) coatings and without or with various concentrations of AgNPs. Initial colonizers on all surfaces were diatoms of the species Coscinodiscus centralis. After 60 days’ exposure to the marine environment, other genera of microalgae and cyanobacteria were observed. Biofilm formation was reduced on all coated coupons to a greater or lesser extent than bare rock, indicating that these nanomaterials’ presence altered biofilms’ formation on calcareous rock negatively on microbial communities’ essentials for ecosystem health.

Natural products (NPs) are specialized metabolites from natural sources, such as plants, animals, fungi, and bacteria, that have had an important role in the discovery and development of new drugs. For many years, bioassay-guided isolation has been the most used strategy for the isolation of bioactive NPs. Chemometrics is the science of relating the measurements made in a system or chemical process to the application of mathematical and statistical methods. Recently, chemometric techniques have been widely used in NP studies, including the detection of bioactive NPs from medicinal plants, chemotaxonomy, determination of geographical origin of medicinal plants and herbal products, and for quality control purposes. In this review, we propose a chemometric-enhanced strategy as a new approach for speeding up the isolation of bioactive NPs while reducing the quantities of biological material and organic solvents used.

This work describes the use of Colubrina greggii as a model to investigate the use of chemometric analysis combined with data from a leishmanicidal bioassay, using Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures (O-PLS), to detect biologically active natural products in crude extracts from plants having little or no phytochemical information. A first analysis of the HPLC-UV profiles of the extract and its semi-purified fractions using both Principal Component Analysis (PCA) and Orthogonal Partial Least Squares (O-PLS) indicated that the components at tR 48.2, 48.7, 51.8min correlated with the variation in bioactivity. However, a further O-PLS analysis of the HPLC-UV profiles of fractions obtained through a final semi-preparative HPLC purification showed two components at tR 48.7 and 49.5min which correlated with the variation of the bioactivity in a high performance predictive model, with high determination coefficient, high correlation coefficient values (R(2) and Q(2)=0.99) and a low root mean square error (RMSE=0.018). This study demonstrates that the association of chemometric analysis with bioassay results can be an excellent strategy for the detection and isolation of bioactive metabolites from phytochemically unknown plant crude extracts.