HPTLC and FTIR Fingerprinting of Olive Leaves Extracts and ATR-FTIR Characterisation of Major Flavonoids and Polyphenolics.
TL;DR: In this paper, the effect of spontaneous microbial maceration on the release and extraction of the flavonoids and phenolics from olive leaves was analyzed using ATR-FTIR spectroscopy.
Abstract: The aim of this study was to analyse the effect of spontaneous microbial maceration on the release and extraction of the flavonoids and phenolics from olive leaves. Bioprofiling based on thin-layer chromatography effect-directed detection followed by ATR-FTIR spectroscopy proved to be a reliable and convenient method for simultaneous comparison of the extracts. Results show that fermentation significantly enhances the extraction of phenolic compounds and flavonoids. The polyphenolic content was increased from 6.7 µg GAE (gallic acid equivalents) to 25.5 µg GAE, antioxidants from 10.3 µg GAE to 25.3 µg GAE, and flavonoid content from 42 µg RE (rutin equivalents) to 238 µg RE per 20 µL of extract. Increased antioxidant activity of fermented ethyl acetate extracts was attributed to the higher concentration of extracted flavonoids and phenolic terpenoids, while increased antioxidant activity in fermented ethanol extract was due to increased extraction of flavonoids as extraction of phenolic compounds was not improved. Lactic acid that is released during fermentation and glycine present in the olive leaves form a natural deep eutectic solvent (NADES) with significantly increased solubility for flavonoids.
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TL;DR: In this article , a cold methanolic extract of Olea europaea leaves was used to identify the bioactive constituents and antibacterial activity of the leaves of the plant.
4 citations
TL;DR: In this article , a polyphenols-rich plant extract has been obtained from olive-tree leaves, and its ability to contribute to reducing four metals, namely, Ag, Cu, Cr, and Sn, that are present in scrap PCBs has been studied.
Abstract: Recycling printed circuit boards (PCBs) is becoming a source of precious metals and an alternative to conventional mining. This phenomenon is now known as "urban mining." In this work, a polyphenols-rich plant extract has been obtained from olive-tree leaves, and its ability to contribute to reducing four metals, namely, Ag, Cu, Cr, and Sn, that are present in scrap PCBs has been studied. Three reductants (NaBH4, Fe°, and the olive-tree leaves extract) have been used to recover these valuable metals. An attempt has been made to minimize the concentration of the first two, replacing them with a natural, cheaper, and less toxic reductant. To achieve this goal, a computer-assisted factorial, composed, centered, orthogonal, and rotatable statistical design of experiments (FCCORD) has been used to build the experimental matrix to be carried out in the laboratory and, next, for the statistical treatment of the results. The results show that it is possible to achieve only a partial recovery of the four metals (silver, copper, chromium, and tin) from PCBs leachates by using sodium borohydride, iron, and the extract separately. In other words, none of these three reductants alone can completely remove any of the four metals in the leachate. Nevertheless, using the statistical design of experiments, the total recovery of the four metals has been achieved by combining the three reductants in the appropriate concentrations. Hence, polyphenols-rich plant extracts in general and olive-tree leaves extract in particular can be regarded as promising coadjuvants in the rising field of urban mining.
3 citations
TL;DR: The results obtained indicate the growth stimulation of Lb.
Abstract: Nutraceuticals are experiencing a high-rise use nowadays, which is incomparable to a few years ago, due to a shift in consumers’ peculiarity tendencies regarding the selection of alternatives to Western medicine, potential immunity boosters, or gut-health promoters. Nutraceuticals’ compositions and actual effects should be proportional to their sought-after status, as they are perceived to be the middle ground between pharma rigor and naturally occurring actives. Therefore, the health benefits via nutrition, safe use, and reduction of potential harm should be the main focus for manufacturers. In this light, this study assess the nutritional profile (proteins, fats, fibers, caloric value, minerals) of a novel formulated nutraceutical, its physico-chemical properties, FTIR spectra, antioxidant activity, anthocyanins content, and potential hazards (heavy metals and microbiological contaminants), as well as its cytotoxicity, adherence, and invasion of bacteria on HT-29 cells, as well as its evaluation of beneficial effect, potential prebiotic value, and duplicity effect on gut microbiota in correlation with Regulation (EC) No 1924/2006. The results obtained indicate the growth stimulation of Lb. rhamnosus and the inhibitory effects of E.coli, Ent. Faecalis and Lc. lactis. The interaction between active compounds suggested a modulator effect of the intestinal microbiota by reducing the number of bacteria that adhere to epithelial cells or by inhibiting their growth.
2 citations
TL;DR: In this article , a novel composite food preservative for fresh-cut lettuce using flavonoids and chitosan from sea buckthorn leaves (SBL) was created, and the effect of FSL-1 concentration on the physicochemical properties, including their film-forming ability, antioxidant capacity and ability to prevent bacterial growth, was analyzed.
Abstract: The purpose was to create a novel composite food preservative for fresh-cut lettuce using flavonoids and chitosan from sea buckthorn leaves (SBL). Sea buckthorn leaves were extracted with ethanol as the extraction solvent and ultrasonic-assisted extraction to obtain flavonoid from sea buckthorn leaf crude (FSL), and then the FSL was secondarily purified with AB-8 resin and polyamide resin to obtain flavonoid from sea buckthorn leaf purified (FSL-1). Different concentrations of FSL-1 and chitosan were made into a composite preservative (FCCP) by magnetic stirring and other methods, containing 1% chitosan preservative (CP) alone, 0.5–2 mg/ml of FSL-1 and 1% chitosan composite preservative (FCCP-1, FCCP-2, FCCP-3, and FCCP-4), and the FSL-1 concentrations were analyzed the effect of FSL-1 concentration on the physicochemical properties of the composite preservatives, including their film-forming ability, antioxidant capacity and ability to prevent bacterial growth, was analyzed. To further investigate the effect of the combined preservatives on fresh-cut lettuce, different FCCPs were applied to the surface was stored at 4°C for 7 days. Then the changes in weight loss, hardness, browning index, total chlorophyll content, SOD and MDA were analyzed. It was used to assess the physicochemical indicators of fresh-cut lettuce throughout storage. According to the results of Fourier transform infrared spectroscopy, FSL-1 and chitosan interacted to form hydrogen bonds, and the contact angle and viscosity of FCCP increased on both horizontal glass and polystyrene plates, indicating the good film-forming properties of the composite preservation solution. With the diameter of the antibacterial zone of Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes being (21.39 ± 0.22), (17.43 ± 0.24), (15.30 ± 0.12), and (14.43 ± 0.24) mm, respectively. It was proved that the antibacterial activity of FCCP became stronger with the increase of FSL-1 concentration and had the best antibacterial effect on S. aureus. The complex preservative showed the best scavenging effect on ferric reducing antioxidant capacity, DPPH radicals (96.64%) and 2,2’-Azinobis- (3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals (99.42%) when FSL-1 was added at 2 mg/ml. When fresh-cut lettuce was coated with FCCP for the same storage time, various indicators of lettuce such as weight loss, hardness, browning index, SOD activity and MDA content were better than the control group showing good potential in fresh-cut vegetables and fruits preservation. FCCP holds great promise for food safety quality and shelf-life extension as a new natural food preservative. The waste utilization of sea buckthorn leaves can greatly improve his utilization and economic benefits.
TL;DR: In this paper , a method is presented that aims to reduce the estimated wall times for DFT calculations that result in the same or higher degree of accuracy in the second derivatives over energy than is the case with the regular computational route (i.e., optimizing the reaction system at a lower model and then recalculating the energies at a higher level of theory).
Abstract: Antioxidants are various types of compounds that represent a link between biology and chemistry. With the development of theoretical and computational methods, antioxidants are now being studied theoretically. Here, a novel method is presented that aims to reduce the estimated wall times for DFT calculations that result in the same or higher degree of accuracy in the second derivatives over energy than is the case with the regular computational route (i.e., optimizing the reaction system at a lower model and then recalculating the energies at a higher level of theory) by applying the inversion of theory level to the universal chemical scavenger model, i.e., phenol. The resulting accuracy and wall time obtained with such a methodological setup strongly suggest that this methodology could be generally applied to antioxidant thermodynamics for some costly DFT methods with relative absolute deviation.
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TL;DR: Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.
1,614 citations
TL;DR: A biotechnological production of rosmarinic acid with plant cell cultures has been proposed to act as a preformed constitutively accumulated defence compound in plants.
1,145 citations
TL;DR: New protocols for processing and determining phenolics in food matrices must be devised in order to release bound phenolics and for quality control in the growing functional food industry.
748 citations
TL;DR: In this article, short-chain, carboxylic acids can be divided into three groups as Al detoxifiers: strong (citric, oxalic, tartaric), moderate (malic, malonic, salicylic), and weak (succinic, lactic, formic, acetic, phthalic).
Abstract: Aluminum has long been recognized as a major limiting factor for root growth in acid subsoils, but little has been done to delineate toxic and nontoxic forms of soil-solution Al. In an effort to determine if the presence of organic acids in soil solutions affected Al phytotoxicity, short-term, split-root experiments were conducted with cotton (Gossypium hirsutum L.) taproots as the growth indicator. Based on pure solution experiments, short-chain, carboxylic acids can be divided into three groups as Al detoxifiers: (i) strong (citric, oxalic, tartaric), (ii) moderate (malic, malonic, salicylic), and (iii) weak (succinic, lactic, formic, acetic, phthalic). The Al detoxifying capacities of these acids were positively correlated with the relative position of OH/COOH groups on their main C chain, positions that favored the formation of stable 5- or 6-bond ring structures with Al. In addition, analyses of soil solutions from several eluviated acid horizons (E, EB, BE) revealed the presence of several organic acids whose concentrations were generally higher in forested than in cultivated soils. Based on these concentrations, total solution Al (as measured by ICAP) was partitioned into monomeric Al (Al³⁺ + hydroxy-Al species) and complexed Al (Al-organic acid complexes). The latter accounted for 93 and 76% of the total solution Al concentrations of the two acid subsoils into which elongation rate of cotton taproot was studied. Root growth was significantly correlated with monomeric Al but not with total Al in soil solutions.
712 citations
TL;DR: It is suggested that quercetin glucoside is actively absorbed from the small intestine, whereas quercettin rutinoside is absorbed fromThe colon after deglycosylation, suggesting that Absorption of other food components might also be enhanced by attachment of a glucose group.
Abstract: Flavonoids are antioxidants present in plant foods. They occur mainly as glycosides, i.e. linked with various sugars. It is uncertain to what extent dietary flavonoid glycosides are absorbed from the gut. We investigated how the nature of the sugar group affected absorption of one major flavonoid, quercetin. Quercetin linked with glucose, i.e. quercetin glucoside and quercetin linked with rutinose, i.e. quercetin rutinoside, both occur widely in foods. When we fed these compounds to nine volunteers, the peak concentration of quercetin (Cmax) in plasma was 20 times higher and was reached (Tmax) more than ten times faster after intake of the glucoside (Cmax = 3.5 ± 0.6 μM (mean ± SE); Tmax < 0.5 h) than after the rutinoside (Cmax = 0.18 ± 0.04 μM; Tmax = 6.0 ± 1.2 h). The bioavailability of the rutinoside was only 20% of that of the glucoside. We suggest that quercetin glucoside is actively absorbed from the small intestine, whereas quercetin rutinoside is absorbed from the colon after deglycosylation. Abso...
507 citations