Several biological processes in prokaryotic and eukaryotic organisms require the presence of glycolipids (biosurfactants), compounds with both hydrophilic and hydrophobic groups in their structure. They constitute the backbone of different metabolic functions and biological structures such as cell membranes. Besides being structural components, glycolipids show surface activity in the interfaces and are mainly produced by microorganisms. Interest in biosurfactants has increased considerably in recent times due to their applications in the environmental, oil, food, and pharmaceutical industries, since they have unique properties such as low toxicity, high biodegradability, environmentally friendly, foaming capacity, high selectivity and specificity at extreme temperatures, pH and salinity, as well as biological activity. All of these properties are considered advantages over other chemical surfactants, and therefore glycolipids are considered a good alternative, given the current interest on sustainable development. The present work shows a general view of bio-surfactants of microbial origin, particularly of glycolipids, referring to several studies on their biological activity that have revealed their great potential in the medical-biological field, discovering interesting possibilities for their therapeutic application in the near future.

Cactus pears (Opuntia ficus-indica) are draught resistant plants originated in Mexico. Their flattened stem segments, called cladodes, have moisture, protein and fibre contents of 92, 1-2 and 4-6% respectively, and a pectin content in the range of 0.8-3.3% depending on the species. They also contain certain concentration of carotenoids which are of special interest because of their antioxidant activity. This work is aimed to identify and quantify the main carotenoids present in the stems and to evaluate the effect of thermal treatments on the antioxidant activity and concentration of carotenoids and phenolic compounds. The carotenoids -cryptoxanthin, -carotene and lutein were identified in the cladodes, the latter having the highest concentration. Thermal treatments increased the extractability of these pigments and the antioxidant activity was related to the carotenoids concentration. Total phenolic content decreased after the thermal treatments; however this result had little effect on the antioxidant activity. Mucilage present in the stems decreased the extractability of the carotenoids.

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The interest in cacao flavanols is still growing, as bioactive compounds with potential benefits in the prevention of chronic diseases associated with inflammation, oxidative stress and metabolic disorders. Several analytical methodologies support that the flavanols in cacao-derived products can be absorbed, have bioactive properties, and thus can be responsible for their beneficial effects on human health. However, it must be considered that their biological actions and underlying molecular mechanisms will depend on the concentrations achieved in their target tissues. Based on the antioxidant properties of cacao flavanols, this review focuses on recent advances in research regarding their potential to improve metabolic syndrome risk factors. Additionally, it has included other secondary plant metabolites that have been investigated for their protective effects against metabolic syndrome. Studies using laboratory animals or human subjects represent strong available evidence for biological effects of cacao flavanols. Nevertheless, in vitro studies are also included to provide an overview of these phytochemical mechanisms of action. Further studies are needed to determine if the main cacao flavanols or their metabolites are responsible for the observed health benefits and which are their precise molecular mechanisms.