Temperature-Dependent Olive Pomace Extraction for Obtaining Bioactive Compounds Preventing the Death of Murine Cortical Neurons.

High-pressure and temperature extraction (HPTE) can effectively recover bioactive compounds from olive pomace (OP). HPTE extract obtained by extracting OP with ethanol and water (50:50 v/v) at 180 °C for 90 min demonstrated a pronounced ability to preserve intracellular calcium homeostasis, shielding neurons from the harmful effects induced by N-methyl-d-aspartate (NMDA) receptor (NMDAR) overactivation, such as aberrant calpain activation. In this study, the extraction temperature was changed from 37 to 180 °C, and the extracts were evaluated for their antioxidant potency and ability to preserve crucial intracellular Ca2+-homeostasis necessary for neuronal survival. Additionally, to verify the temperature-induced activity of the extract, further extractions on the exhausted olive pomace were conducted, aiming to identify variations in the quality and quantity of extracted phenolic molecules through HPLC analysis. The results revealed a significant increase in bioactive compounds as a function of temperature variation, reaching 6.31 ± 0.09 mgCAE/mL extract for the extraction performed at 180 °C. Subsequent extraction of the exhausted residues yielded extracts that remained active in preventing calcium-induced cell death. Moreover, despite increased antiradical power, extracts re-treated at 180 °C did not display cell protection activity. Our results indicate that the molecules able to maintain physiological Ca2+-homeostasis in murine cortical neurons in conditions of cytotoxic stimulation of NMDAR are wholly recovered from olive pomace only following extraction performed at 180 °C.

A Bioactive Olive Pomace Extract Prevents the Death of Murine Cortical Neurons Triggered by NMDAR Over-Activation.

We have recently demonstrated that bioactive molecules, extracted by high pressure and temperature from olive pomace, counteract calcium-induced cell damage to different cell lines. Here, our aim was to study the effect of the same extract on murine cortical neurons, since the preservation of the intracellular Ca2+-homeostasis is essential for neuronal function and survival. Accordingly, we treated neurons with different stimuli in order to evoke cytotoxic glutamatergic activation. In these conditions, the high-pressure and temperature extract from olive pomace (HPTOPE) only abolished the effects of N-methyl-d-aspartate (NMDA). Particularly, we observed that HPTOPE was able to promote the neuron rescue from NMDA-induced cell death. Moreover, we demonstrated that HPTOPE is endowed with the ability to maintain the intracellular Ca2+-homeostasis following NMDA receptor overactivation, protecting neurons from Ca2+-induced adverse effects, including aberrant calpain proteolytic activity. Moreover, we highlight the importance of the extraction conditions used that, without producing toxic molecules, allow us to obtain protecting molecules belonging to proanthocyanidin derivatives like procyanidin B2. In conclusion, we can hypothesize that HPTOPE, due to its functional and nontoxic properties on neuronal primary culture, can be utilized for future therapeutic interventions for neurodegeneration.

Bioactive compounds and antioxidant potential for polyphenol-rich cocoa extract obtained by agroindustrial residue.

Processing of cocoa (Theobroma cacao L.) beans responsible for agricultural exports leads to large amounts of solid waste that were discarded, however, this one presents high contents of metabolites with biological activities. The major objective of this study was to valorise cocoa agroindustrial residue obtained by hydraulic pressing for extract rich in antioxidants. For it, the centesimal composition of residue was investigated, the green extraction was carried out from the residue after, the bioactive compounds, sugar contents and screaming by HPTLC were quantified for extract. The extract has a total polyphenol content of 229.64 mg/g and high antioxidant activity according to ABTS 225.0 µM/g. HTPLC analysis confirmed the presence in the extract, residue of terpenes, sesquiterpenes, flavonoids and antioxidant activity. These results, as a whole, suggest that the extract from the cocoa residue has interesting characteristics to alternative crops with potential industrial uses.

Immobilization of Aspergillus ficuum tannase in calcium alginate beads and its application in the treatment of boldo (Peumus boldus) tea.

Tannase (tannin acyl hydrolase, E.C. 3.1.1.20) is an enzyme that catalyzes the hydrolysis of ester and depside linkages in hydrolysable tannins such as tannic acid, releasing gallic acid and glucose. It has several commercial applications in food industry, among which are gallic acid production, reduction of tannin content in fruit juices, and preparation of instantaneous tea. In this study we immobilized Aspergillus ficuum tannase in calcium alginate beads and then used it to treat boldo (Peumus boldus) tea. Such a technique allowed entrapping tannase with a 75% efficiency and appreciably increasing its thermal and pH stability compared with the free enzyme. Storage stability and reuse of the immobilized enzyme were very promising, in that about 60% of starting enzyme activity was retained after bead storage for 90 days at 4 °C or after six cycles of use. Boldo tea treatment with immobilized tannase for 120 min at 40 °C led to 31 and 60% removals of tannins and epigallocatechin gallate, an increase of about two orders of magnitude in gallic acid content, 56 and 109% increases in total flavonoids and epigallocatechin contents, a 42.8% increase in antioxidant activity and significant enhancements of tea color, clarity and pH.

Antioxidant activity and biological evaluation of olive pomace extract.

The antiradical power of the methanol extracts of olive pomace (Taggiasca cultivar) achieved by high-pressure-high-temperature reactor were investigated using ABTS•(+) and DPPH• assays. The highest antioxidant activity was quantified at 90 min of contact time and 180°C of extraction temperature (64.19 ± 0.16 µg(TE) L(-1) and 15.80 ± 0.62 µg(DPPH) µL(extract) (-1)). The extract with high-antioxidant power resulted to be effective to counteract key aspects of cellular oxidation sensitive mechanisms and inflammation associated to vascular diseases. A linear correlation (p < 0.05) between total polyphenol contents and antioxidant capacity was given by the ABTS•(+) method (R (2) = 0.9184) and DPPH assay (R (2 )= 0.7062).