Combination of Fenugreek and Quinoa Husk as Sources of Steroidal and Triterpenoid Saponins: Bioactivity of Their Co-Extracts and Hydrolysates.

Saponins, both steroidal and triterpenoid, exhibit distinct bioactivities. However, they are not commonly found together in natural sources; instead, sources tend to be rich in one type or another and mainly in the form of saponins rather than the sapogenin aglycones. Developing co-extracts containing both saponin or sapogenin types would be a strategy to harness their respective bioactivities, yielding multibioactive extracts. Therefore, this study evaluates the bioactivity (hypolipidemic, antioxidant, and anti-inflammatory activities) of co-extracts from fenugreek seeds (steroidal-rich saponins) and quinoa husk (triterpenoid-rich saponins), co-extracted at varying proportions, alongside their respective sapogenin-rich hydrolysates. Pancreatic lipase inhibition increased with fenugreek content in co-extracts, especially in sapogenin-rich variants. The latter substantially interfered with cholesterol bioaccessibility (90% vs. 15% in sapogenin-rich extracts). Saponin-rich co-extracts exhibited reduced cytokine release with increased fenugreek content, while sapogenin-rich counterparts showed greater reductions with higher quinoa husk content. Limited cellular antioxidant activities were observed in all extracts, with improved post-hydrolysis bioactivity. Therefore, simultaneous co-extraction of steroidal and triterpenoid sources, such as fenugreek and quinoa husk, as well as their subsequent hydrolysis, are innovative strategies for obtaining multibioactive natural extracts.

Effects of a Mealworm (Tenebrio molitor) Extract on Metabolic Syndrome-Related Pathologies: In Vitro Insulin Sensitivity, Inflammatory Response, Hypolipidemic Activity and Oxidative Stress.

The mealworm (Tenebrio molitor Linnaeus 1758) is gaining importance as one of the most popular edible insects. Studies focusing on its bioactivities are increasing, although alternative forms of consumption other than the whole insect or flour, such as bioactive non-protein extracts, remain underexplored. Furthermore, the incidence of metabolic syndrome-related pathologies keeps increasing, hence the importance of seeking novel natural sources for reducing the impact of certain risk factors. The aim was to study the potential of a non-protein mealworm extract on metabolic syndrome-related pathologies, obtained with ethanol:water (1:1, v/v) by ultrasound-assisted extraction. We characterized the extract by gas-chromatography mass-spectrometry and assessed its hypolipidemic potential, its ability to scavenger free radicals, to attenuate the inflammatory response in microglial cells, to affect mitochondrial respiration and to enhance insulin sensitivity in mouse hepatocytes. The extract contained fatty acids, monoglycerides, amino acids, certain acids and sugars. The mealworm extract caused a 30% pancreatic lipase inhibition, 80% DPPH· scavenging activity and 55.9% reduction in the bioaccessibility of cholesterol (p = 0.009). The extract was effective in decreasing iNOS levels, increasing basal, maximal and ATP coupled respiration as well as enhancing insulin-mediated AKT phosphorylation at low insulin concentrations (p < 0.05). The potential of a non-protein bioactive mealworm extract against metabolic syndrome-related pathologies is shown, although further studies are needed to elucidate the mechanisms and relationship with compounds.

Microwave-Assisted Acid Hydrolysis vs. Conventional Hydrolysis to Produce Sapogenin-Rich Products from Fenugreek Extracts.

The acid hydrolysis of saponins is commonly performed by conventional heating to produce sapogenin-rich products of bioactive interest, but alternative hydrolysis methods and their impact on bioactivity have been unexplored. We compared the conventional method with microwave-assisted acid hydrolysis (MAAH) of a commercial saponin-rich extract from a typical saponin source, fenugreek, focusing on the study of temperature (100, 120, 130, 140, 150 °C) and time (10, 20, 30, 40 min) of hydrolysis. The impact of these factors was assayed on both the sapogenin yield and the bioactivity of the hydrolyzed products, specifically their antioxidant and lipase inhibitory activities. The highest sapogenin content (34 g/100 g extract) was achieved by MAAH at 140 °C and 30 min, which was higher than conventional hydrolysis at both reference conditions (100 °C, 60 min, 24.6 g/100 g extract) and comparative conditions (140 °C, 30 min, 17 g/100 g extract) (p < 0.001). Typical steroid artifacts from sapogenins were observed in very small amounts, regardless of the method of hydrolysis. Antioxidant activity of MAAH hydrolyzed extracts (around 80% DPPH inhibition) was barely affected by time and temperature, but pancreatic lipase inhibitory activity was higher (>65%) at lower MAAH temperature (<130 °C) and time (<30 min) of hydrolysis. MAAH is shown as a valid alternative to produce selective sapogenin-rich extracts from fenugreek with minor impact on their bioactivities, and whose magnitude can be modulated by the hydrolysis conditions.

Effect of Defatting and Extraction Solvent on the Antioxidant and Pancreatic Lipase Inhibitory Activities of Extracts from Hermetia illucens and Tenebrio molitor.

The production of specific insect extracts with bioactive properties for human health is an emerging and innovative field for the edible insects industry, but there are unexplored extraction factors that might modulate the bioactivity of the extracts. Ultrasound-assisted extracts from T. molitor and H. illucens were produced. Effects of defatting pre-treatment and extraction solvent were evaluated on extraction yield, antioxidant activity and pancreatic lipase inhibitory effect. Chemical characterisation of defatted extracts from H. illucens was performed by GC-MS-FID. Non-defatted extracts showed higher extraction yields. Defatted extracts had similar extraction yields (around 3%). Defatted extracts had higher antioxidant activity, T. molitor being stronger than H. illucens. Antioxidant activity of T. molitor methanol extract was higher than the rest of solvents. Aqueous ethanol improved the antioxidant activity of H. illucens extracts. All extracts inhibited lipase, but no significant effect of defatting and solvent was observed for T. molitor. A significant higher inhibitory activity was observed for H. illucens, the strongest being defatted 100% and 70% ethanol H. illucens extracts. H. illucens extracts contained free amino acids and disaccharides, together with minor fractions of lipids, sterols and organic acids. These results evidence the potential of extracts obtained from edible insects as antioxidants and inhibitors of the pancreatic lipase, a simultaneous multibioactivity that might be favoured by the defatting pre-treatment of the samples and the solvent of extraction.