Squalene is a natural dehydrotriterpenic hydrocarbon (C30H50) with six double bonds, known as an intermediate in the biosynthesis of phytosterol or cholesterol in plants or animals. We have briefly reviewed the natural sources for squalene and focused on the main methods and techniques to obtain and to determine it. Some of its applications in different fields of human activity are also mentioned.

The aim of this study was to establish the best ultrasound assisted extraction (UAE) conditions of saponins from Hedera helix L. leaves and to evaluate the in vitro biocompatibility of the extracts richest in saponins. Different parameters, such as extraction time, temperature, ultrasound power, solvent to plant material ratio, and solvent concentration, were investigated. The most efficient extraction conditions were a temperature of 50 °C, an ultrasound amplitude of 40%, an extraction time of 60 min, a plant material to solvent ratio of 1:20 (w:v), and 80% ethanol as solvent. In vitro cytotoxicity of the extracts richest in saponins and their influence on the DNA content of L929 (NCTC) fibroblasts were tested. Until 200 µg/mL, the studied extracts were cytocompatible with L929 fibroblast cell lines at 48 h of treatment. These in vitro cell culture results provide useful information for further applications of Hedera helix extracts in a pharmaceutical field.

In this study, we present a strategy for valorizing lignocellulosic wastes (licorice root and willow bark) that result from industrial extraction of active principles using water as green solvent and aqueous NaOH solution. The wastes were submitted to severe ultrasound (US) and microwave (MW) treatments. The aim of these treatments was to extract the remaining active principles (using water as a solvent) or to prepare them for cellulose enzymatic hydrolysis to hexoses (performed in an NaOH aqueous solution). The content of glycyrrhizic acid and salicin derivatives in licorice root and willow bark wastes, respectively, were determined. The best results for licorice root were achieved by applying the US treatment for 5 min at 25 °C (26.6 mg glycyrrhizic acid/gDM); while, for willow bark, the best results were achieved by applying the MW treatment for 30 min at 120 °C (19.48 mg salicin/gDM). A degradation study of the targeted compounds was also performed and showed good stability of glycyrrhizic acid and salicin derivatives under US and MW treatments. The soluble lignin concentration prior to enzymatic hydrolysis, as well as the saccharide concentration of the hydrolyzed solution, were determined. As compared with the MW treatment, the US treatment resulted in saccharides concentrations that were 5% and 160% higher for licorice root and willow bark, respectively.

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