Polyphenolic burden and in vitro antioxidant properties of Moringa oleifera root extracts

ntroduction: Moringa oleifera is a small tree with very significant nutritional but alsopharmacological properties and various preparations from almost all parts of the plant (leaves,fruit, stems, bark, roots) are used in folk medicine for treating several ailments. This study aimedto investigating the polyphenolic burden and in vitro antioxidant properties of M. oleifera rootextracts, obtained with solvents covering a range of polarities.Methods: Lyophilised Moringa oleifera roots were extracted with solvents of increasing polarity,including ethyl acetate, butanol, methanol and water. The generated extracts were screened forpolyphenolic load and antioxidant activities, by determining the total polyphenol, total f lavonoid,total f lavanol, antiradical activity and reducing power. Liquid chromatography-mass spectrometrywas also employed to obtain some evidence regarding the nature of the main constituents.Results: The results indicated that both aqueous and methanolic extracts were the richestin total polyphenols, but the aqueous extract also exhibited high reducing power. The liquidchromatography-diode array-mass spectrometry analysis also revealed that the major substancesoccurring in the aqueous extract were relatively polar molecules, but the mass spectral data wereambiguous to assign tentative structures.Conclusion: Polar solvents, such as water, may be effectively used to recover high amounts of M.oleifera root phenolics, which possess important antioxidant properties.&nbsp

Real-Time Abnormal Event Detection for Enhanced Security in Autonomous Shuttles Mobility Infrastructures

Autonomous vehicles (AVs) are already operating on the streets of many countries around the globe. Contemporary concerns about AVs do not relate to the implementation of fundamental technologies, as they are already in use, but are rather increasingly centered on the way that such technologies will affect emerging transportation systems, our social environment, and the people living inside it. Many concerns also focus on whether such systems should be fully automated or still be partially controlled by humans. This work aims to address the new reality that is formed in autonomous shuttles mobility infrastructures as a result of the absence of the bus driver and the increased threat from terrorism in European cities. Typically, drivers are trained to handle incidents of passengers’ abnormal behavior, incidents of petty crimes, and other abnormal events, according to standard procedures adopted by the transport operator. Surveillance using camera sensors as well as smart software in the bus will maximize the feeling and the actual level of security. In this paper, an online, end-to-end solution is introduced based on deep learning techniques for the timely, accurate, robust, and automatic detection of various petty crime types. The proposed system can identify abnormal passenger behavior such as vandalism and accidents but can also enhance passenger security via petty crimes detection such as aggression, bag-snatching, and vandalism. The solution achieves excellent results across different use cases and environmental conditions. Document type: Articl

Glycerol and Glycerol-Based Deep Eutectic Mixtures as Emerging Green Solvents for Polyphenol Extraction: The Evidence So Far

The acknowledgement that uncontrolled and excessive use of fossil resources has become a prime concern with regard to environmental deterioration, has shifted the orientation of economies towards the implementation of sustainable routes of production, through the valorization of biomass. Green chemistry plays a key role in this regard, defining the framework of processes that encompass eco-friendly methodologies, which aim at the development of highly efficient production of numerous bioderived chemicals, with minimum environmental aggravation. One of the major concerns of the chemical industry in establishing sustainable routes of production, is the replacement of fossil-derived, volatile solvents, with bio-based benign ones, with low vapor pressure, recyclability, low or no toxicity, availability and low cost. Glycerol is a natural substance, inexpensive and non-toxic, and it is a principal by-product of biodiesel industry resulting from the transesterification process. The ever-growing market of biodiesel has created a significant surplus of glycerol production, resulting in a concomitant drop of its price. Thus, glycerol has become a highly available, low-cost liquid, and over the past decade its use as an alternative solvent has been gaining unprecedented attention. This review summarizes the utilization of glycerol and glycerol-based deep eutectic mixtures as emerging solvents with outstanding prospect in bioactive polyphenol extraction

Hydroxypropyl-β-Cyclodextrin as a Green Co-Solvent in the Aqueous Extraction of Polyphenols from Waste Orange Peels

There is, to-date, an expanding interest concerning the use of cyclodextrins as green food-grade co-solvents in the aqueous extraction of polyphenols, however, data regarding polyphenol extraction from waste orange peels (WOP) are lacking. On this ground, hydroxypropyl β-cyclodextrin (HP-β-CD), a highly water-soluble cyclodextrin, was used to develop a simple and straightforward methodology for the effective recovery of WOP polyphenols. Process optimization by response surface showed that maximum total polyphenol recovery (26.30 ± 1.49 mg gallic acid equivalents g−1 dry mass) could be accomplished with 15 mM HP-β-CD at 40 °C. On the other hand, integration of ultrasonication pretreatment was found unsuitable, as it resulted in reduced polyphenol yield. Examination of solvent acidity indicated that polyphenol extraction may be enhanced at pH 4, but the difference was non-significant (p > 0.05) compared to yields attained at pH 2, 3, and 5. Extraction of WOP polyphenols with HP-β-CD was shown to provide significantly higher hesperidin yield compared to 60% (v/v) aqueous ethanol, which suggested selectivity of HP-β-CD toward this polyphenolic metabolite

Effect of Methyl β-cyclodextrin on Radical Scavenging Kinetics of Olive Leaf Extracts and Interactions with Ascorbic Acid

Olive leaf (OLL) extracts contain a high load of antioxidant polyphenols with significant pharmacological potency. In this study, the use of a novel natural deep eutectic solvent enabled the effective extraction of OLL polyphenols and their testing as radical scavengers, in the presence or absence of methyl β-cyclodextrin (m-β-CD), using descriptive kinetics. Testing was extended to include interactions with ascorbic acid—a natural powerful antioxidant—by implementing a response surface methodology. The kinetic study showed that m-β-CD may hinder the radical scavenging effect of OLL extracts, yielding lower stoichiometry upon reaction with the radical probe 2,2-diphenyl-1-picrylhydrazy (DPPH). The extension of the reaction time to determine the total stoichiometry confirmed this effect. As a further concurrence, the interactions of OLL extracts with ascorbic acid showed lower radical scavenging performance in the presence of m-β-CD. These results were discussed on the grounds of the role that m-β-CD may play in similar systems

Development of a Low-Temperature and High-Performance Green Extraction Process for the Recovery of Polyphenolic Phytochemicals from Waste Potato Peels Using Hydroxypropyl β-Cyclodextrin

Potato peels (PP) are a major agri-food side-stream originating from potato processing, but to date, their green valorization as a bioresource of antioxidant polyphenols is limited to extraction processes involving mainly water/ethanol-based solvents, whereas other eco-friendly methodologies are scarce. This study aimed at developing a simple, straight-forward and green extraction methodology to effectively recover PP polyphenols, using hydroxypropyl β-cyclodextrin (HP-β-CD). After an initial assay to identify the optimal HP-β-CD concentration that would provide increased extraction yield, optimization based on response surface methodology enabled maximization of the extraction performance, providing a total polyphenol yield of 17.27 ± 0.93 mg chlorogenic acid equivalent g−1 dry mass, at 30 °C. Testing of temperatures higher than 30 °C and up to 80 °C did not favor higher yields. The extracts obtained with HP-β-CD were slightly richer in polyphenols than extracts prepared with conventional solvents, such as aqueous ethanol and methanol, displaying similar antioxidant characteristics. The major polyphenols that could be identified in the extracts were neochlorogenic, chlorogenic, caffeic and ferulic acids. The outcome of this study demonstrated that HP-β-CD may be used as a highly effective green means of recovering PP polyphenols, at near-ambient temperature

Polyphenolic burden and in vitro antioxidant properties of Moringa oleifera root extracts

ntroduction: Moringa oleifera is a small tree with very significant nutritional but alsopharmacological properties and various preparations from almost all parts of the plant (leaves,fruit, stems, bark, roots) are used in folk medicine for treating several ailments. This study aimedto investigating the polyphenolic burden and in vitro antioxidant properties of M. oleifera rootextracts, obtained with solvents covering a range of polarities.Methods: Lyophilised Moringa oleifera roots were extracted with solvents of increasing polarity,including ethyl acetate, butanol, methanol and water. The generated extracts were screened forpolyphenolic load and antioxidant activities, by determining the total polyphenol, total f lavonoid,total f lavanol, antiradical activity and reducing power. Liquid chromatography-mass spectrometrywas also employed to obtain some evidence regarding the nature of the main constituents.Results: The results indicated that both aqueous and methanolic extracts were the richestin total polyphenols, but the aqueous extract also exhibited high reducing power. The liquidchromatography-diode array-mass spectrometry analysis also revealed that the major substancesoccurring in the aqueous extract were relatively polar molecules, but the mass spectral data wereambiguous to assign tentative structures.Conclusion: Polar solvents, such as water, may be effectively used to recover high amounts of M.oleifera root phenolics, which possess important antioxidant properties

The effect of 2-hydroxypropyl β-cyclodextrin on the stability of polyphenolic compounds from Moringa oleifera Lam leaf extracts in a natural low-transition temperature mixture

Polyphenol extracts from Moringa oleifera leaves (MoL) were obtained with a glycerol-based low-transition temperature mixture (LTTM) and a combination of LTTM with 2-hydroxypropyl β-cyclodextrin (HP-β-CD). The extracts were maintained at 4, 22 and 50 °C for 18 days and the antiradical activity (AAR) was recorded to detect modifications in the antioxidant activity of the extracts. AAR displayed a constant decline at every temperature tested, following pseudo first-order kinetics and the decay constants suggested that the presence of HP-β-CD had a protective action, slowing down AAR decline. The analysis of the polyphenolic profiles using liquid chromatography-diode array-mass spectrometry revealed that after storage for 18 days at 50 °C, the major quercetin glycosides occurring in MoL were extensively degraded. Based on the detection of protocatechuic acid in the stored extracts, putative pathways of flavonol glycoside degradation were proposed. It was concluded that the decomposition of these components was mainly responsible for the AAR decline observed

Sustainable Exploitation of Waste Orange Peels: Enrichment of Commercial Seed Oils and the Effect on Their Oxidative Stability

The current project aimed at examining the effect of the enrichment of commercial seed oils with waste orange peel (WOP) extracts on their polyphenolic profiles and resistance against oxidation. Polyphenol-containing WOP extracts were produced using a novel combination of ethanol and triacetin, and they were incorporated into seed oils (sunflower, soybean, corn oil), at a level of 36.87 mg per kg of oil. The oils were then stored at 60 °C, for 58 days. By performing a Rancimat test, it was shown that enrichment of sunflower, soybean, and corn oils with WOP extracts did not provoke any prooxidant effects, but, to the contrary, exerted an antioxidant action, with protection factors varying from 1.01 to 1.61. Furthermore, in all cases examined, it was demonstrated that, during the storage period, the stabilizing effect of WOP extract against oxidation was comparable to that observed in oil samples containing 200 mg BHT per kg oil. This outcome was ascertained by measuring the onset of peroxide value, thiobarbituric-acid-reactive substances, and the TOTOX value. Furthermore, it was revealed that the Trolox-equivalent antiradical activity of the enriched oils exhibited a decline at the end of the examination period, a fact most probably attributed to the depletion of the antioxidants occurring in the oils. It was concluded that the method proposed might be a means of stabilizing commercial seed oils against oxidation, and of enhancing their nutritional value by enriching them with natural polyphenols

Evaluation of Pulsed Electric Field Polyphenol Extraction from Vitis vinifera, Sideritis scardica and Crocus sativus

This study exploited the application of pulsed electric field (PEF) on the recovery of polyphenols from aerial parts of Sideritis scardica, tepals of Crocus sativus, and fruits of Vitis vinifera. Short pulses of 10 μs in a period of 1 ms were applied to the plant material, while different electric field intensities, 1.2 to 2.0 kV/cm were tested to optimize the procedure. The content in total polyphenols and the polyphenolic profile of the plant extracts were evaluated. Along with PEF samples, control samples were prepared for comparison. PEF treatment enhanced the recovery in total polyphenols for all the three plants examined. A significant increase was noticed in each plant tested and PEF condition applied, though lower electric field intensities up to 1.4 kV/cm proved to be more effective. Under the optimum electric field intensities, 1.4 kV/cm for V. vinifera and 1.2 kV/cm for S. scardica and C. sativus, increases of 49.15%, 35.25%, and 44.36% in total polyphenol content, respectively, were achieved. Additionally, an 85% increase of quercetin 3-rutinoside for V. vinifera, a 56% of apigenin 7-O-glucoside for S. scardica, and a 64% increase for kaempferol 3-O-glucoside for C. sativus were obtained