Prodigiosin: a promising biomolecule with many potential biomedical applications.

Pigments are among the most fascinating molecules found in nature and used by human civilizations since the prehistoric ages. Although most of the bio-dyes reported in the literature were discovered around the eighties, the necessity to explore novel compounds for new biological applications has made them resurface as potential alternatives. Prodigiosin (PG) is an alkaloid red bio-dye produced by diverse microorganisms and composed of a linear tripyrrole chemical structure. PG emerges as a really interesting tool since it shows a wide spectrum of biological activities, such as antibacterial, antifungal, algicidal, anti-Chagas, anti-amoebic, antimalarial, anticancer, antiparasitic, antiviral, and/or immunosuppressive. However, PG vehiculation into different delivery systems has been proposed since possesses low bioavailability because of its high hydrophobic character (XLogP3-AA = 4.5). In the present review, the general aspects of the PG correlated with synthesis, production process, and biological activities are reported. Besides, some of the most relevant PG delivery systems described in the literature, as well as novel unexplored applications to potentiate its biological activity in biomedical applications, are proposed.

Simple colorimetric method to determine the in vitro antioxidant activity of different monoterpenes.

The development of simple, fast and reproducible techniques that provide information about the antioxidant activity (AA) of different compounds is essential to screen and discover new molecules with potential applications in the therapeutic, cosmetic, toxicological and food fields. Here, a novel and simple colorimetric method ("BCB assay") is proposed for measuring the AA of chemical compounds by protection of the reporter dye Brilliant Cresyl Blue (BCB) from loss of color due to oxidation by hypochlorite (a physiological oxidant). The decay in BCB blue color (λmax = 634 nm) in the presence of hypochlorite occurred in only 5 min and was used to track the AA of different molecules. Particularly, the AA of monoterpenes was demonstrated and used to quantify them at milimolar concentrations. Natural antioxidants like vitamins C and E, resveratrol, dithiothreitol, N-actyl-l-cysteine and glutathione were used as controls to validate the assay. Linalool, geraniol and 1,8-cineole were tested and showed in vitro AA in a concentration-dependent manner. The monoterpene concentrations providing 50% protection against oxidation (AA50) were 2.3, 36.2 and 135.0 mM for linalool, geraniol and 1,8-cineole respectively, suggesting interesting AA. The method provides a useful, fast, simple and low-cost tool to determine the in vitro AA of different molecules.