Effects of Ultrasound-Assisted Extraction and Solvent on the Phenolic Profile, Bacterial Growth, and Anti-Inflammatory/Antioxidant Activities of Mediterranean Olive and Fig Leaves Extracts

Effect of olive leaf phytochemicals on the anti-acetylcholinesterase, anti-cyclooxygenase-2 and ferric reducing antioxidant capacity

In this study, the phytochemical profile of fifty olive leaves (OL) extracts from Spain, Italy, Greece, Portugal, and Morocco was characterized and their anti-cholinergic, anti-inflammatory, and antioxidant activities were evaluated. Luteolin-7-O-glucoside, isoharmnentin, and apigenin were involved in the acetylcholinesterase (AChE) inhibitory activity, while oleuropein and hydroxytyrosol showed noteworthy potential. Secoiridoids contributed to the cyclooxygenase-2 inhibitory activity and antioxidant capacity. Compounds such as oleuropein, ligstroside and luteolin-7-O-glucoside, may exert an important role in the ferric reducing antioxidant capacity. It should be also highlighted the role of hydroxytyrosol, hydroxycoumarins, and verbascoside concerning the antioxidant activity. This research provides valuable insights and confirms that specific compounds within OL extracts contribute to distinct anti-cholinergic, anti-inflammatory, and anti-oxidative effects.

High Antiparasitic and Antimicrobial Performance of Biosynthesized NiO Nanoparticles via Wasted Olive Leaf Extract

Background

Nowadays, recycling agricultural waste is of the utmost importance in the world for the production of valuable bioactive compounds and environmental protection. Olive leaf bioactive compounds have a significant potential impact on the pharmaceutical industry. These compounds possess remarkable biological characteristics, including antimicrobial, antiviral, anti-inflammatory, hypoglycemic, and antioxidant properties.

Methods

The present study demonstrates a green synthetic approach for the fabrication of nickel oxide nanoparticles (NiO-olive) using aqueous wasted olive leaf extract. Calcination of NiO-olive at 500°C led to the fabrication of pure NiO nanoparticles (NiO-pure). Different techniques, such as thermal gravimetric analysis (TGA), Fourier-transform infrared spectra (FTIR), ultraviolet-visible spectra (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM) fitted with energy-dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM), were used to characterize both NiO-olive and NiO-pure. The extract and nanoparticles were assessed for antiparasitic activity against adult ticks (Hyalomma dromedarii) and antimicrobial activity against Bacillus cereus, Pseudomonas aeruginosa, Aspergillus niger, and Candida albicans.

Results

From XRD, the crystal sizes of NiO-olive and NiO-pure were 32.94 nm and 13.85 nm, respectively. TGA, FTIR, and EDX showed the presence of olive organic residues in NiO-olive and their absence in NiO-pure. SEM and TEM showed an asymmetrical structure of NiO-olive and a regular, semi-spherical structure of NiO-pure. UV-Vis spectra showed surface plasmon resonance of NPs. Antiparasitic activity showed the highest mortality rate of 95% observed at a concentration of 0.06 mg/mL after four days of incubation. The antimicrobial activity showed the largest inhibition zone diameter of 33 ± 0.2 mm against the Candida albicans strain.

Conclusion

Nanoparticles of NiO-olive outperformed nanoparticles of NiO-pure and olive leaf extract in both antiparasitic and antimicrobial tests. These findings imply that NiO-olive may be widely used as an eco-friendly and effective antiparasitic and disinfection of sewage.

LC-MS methods combination for identification and quantification of trans-sinapoylquinic acid regioisomers in green coffee

The present study aims to both identify and quantify trans-sinapoylquinic acid (SiQA) regioisomers in green coffee by combined UHPLC-ESI-QqTOF-MS/MS and UHPLC-ESI-QqQ-MS/MS methods. Among the various mono-acyl chlorogenic acids found in green coffee, SiQA regioisomers are the least studied despite having been indicated as unique phytochemical markers of Coffea canephora (known as Robusta). The lack of commercially available authentic standards has been bypassed by resorting to the advantages offered by high-resolution LC-MS as far as the identification is concerned. SiQA regioisomers have been identified in several samples of Robusta and Coffea arabica (known as Arabica) commercial lots from different geographical origin and, for the first time, in different samples of coffee wild species (Coffea liberica and Coffea pseudozanguebariae). Quantification (total SiQA ranging from 3 to 5 mg/100 g) let to reconsider these chlorogenic acids as unique phytochemical markers of Robusta being present in the same quantity and distribution in C. liberica as well. Gardeniae Fructus samples (fruits of Gardenia jasminoides) have additionally been characterized as this matrix is recognized as one of the few naturally occurring SiQA sources. The SiQA regioisomer content (total SiQA about 80 mg/100 mg) fully supports the proposal to use this matrix as a surrogate standard for further studies.

Exploring the Antioxidant, Neuroprotective, and Anti-Inflammatory Potential of Olive Leaf Extracts from Spain, Portugal, Greece, and Italy

The leaves of the olive tree (Olea europaea L.) are one of the major solid wastes from the olive industry. Globally, the European Union is the largest producer of olive by-products, with Spain, Italy, Greece, and Portugal accounting for almost the entire production. Many questions remain to be solved concerning olive leaves (OL), including those related to possible differences in composition and/or biological activities depending on their geographical origin. In the present work, OL from Spain, Italy, Greece, and Portugal have been characterized according to their phytochemical profile, antioxidant capacity, neuroprotective activity, and anti-inflammatory effects. The Spanish and Italian OL samples presented the highest antioxidant and neuroprotective activities, while the Greek OL showed the lowest. These results were strongly associated with the content of oleoside methyl ester and p-hydroxybenzoic acid for the Spanish and Italian samples, respectively, whereas the content of decarboxymethyl elenolic acid dialdehyde form (hydrated) was negatively associated with the mentioned biological activities of the Greek samples. No country-related effect was observed in the anti-inflammatory activity of OL. Comprehensively, this work could provide a useful tool for manufacturers and R&D departments in making environmentally friendly decisions on how OL can be used to generate nutraceutical products based on the composition and origin of this by-product.

Impact of Olive Oil Constituents on C-reactive Protein: In silico Evidence

Pain is a sensation a humans sense as a protective mechanism against physical injury. This sensation is closely related to inflammation. It ranges from mild to highly obnoxious. It is well-known that the levels of the inflammatory biomarker, C-reactive protein (CRP), increase manifold in acute inflammation and pain. Olive oil, known to have many phytochemicals, has been traditionally used to alleviate pain. Amongst major phenolic compounds in olive oil are oleuropein (OLE), hydroxytyrosol (HT), tyrosol, and oleocanthal. Whether the analgesic and anti-inflammatory properties in olive oil are due to any specific interections is not known. Therefore, this study aimed to elucidate the possible anti-inflammatory and anti-nociceptive properties in those major phenolic compounds by using molecular docking software MOE 2015, comparing the energy value and binding site of phenolic compounds to that of well-known synthetic non-steroidal anti-inflammatory drugs (NSAIDs) and phosphocholine. The docking experiment showed that all compounds could directly interact with CRP. Oleuropein had the most potent interaction with CRP (-7.7580), followed by indomethacin (-6.0775), oleocanthal (-5.5734), ibuprofen (-5.3857), phosphocholine (-4.3876), HT (-4.2782), and tyrosol (-4.2329). Interestingly, the present study found other phytochemicals in olive oil that can be exploited as potential, safe, and cost-effective lead compound(s) for analgesic and anti-inflammatory activity, as supported by its molecular docking data.

Effect of nano extracts of olea europaea leaves, ficus carica and liraglutide in lipidemic liver of type 2 diabetic rat model

The study aimed to evaluate the impact of Ficus carica mixture and Olea europaea leaf nano extracts, and liraglutide, on liver tissue and serum lipids in type 2 diabetic male albino rat model. Forty rats were divided equally into 4 groups were used. Group 1 was the non-diabetic control group. The animals in Groups 2–4 was injected intraperitoneally with a single dose of 60 mg/kg b.w. Streptozotocin to induce a diabetic rat model. Group 2 served as a positive control for diabetes. 0.02 mg/kg b.w./day of Liraglutide gave to groups 3 and 4 and 4.8 ng/ml × 10⁵ b.w./day of a mixture of the nano extracts, respectively. Eight weeks after treatment, the animals were sacrificed. Blood was collected for glucose analysis and serum low-density lipoprotein, high-density lipoprotein, total cholesterol, and triglycerides analysis, and the livers processed for histopathological examination. The elevated lipid profiles and blood glucose levels in diabetic group (Group 2) were significantly reduced (p < 0.001) following the administration of liraglutide and nano extracts in Groups 3 and 4. Progressive fatty acid changes were found in the liver sections, indicated by the deposition of various sizes of lipid droplets in most liver lobules, along with patchy hepatocyte necrosis. These pathological changes were ameliorated in the liraglutide- and nano-extract-treated rats. Treatment with the nano extracts resulted in significant power assays associated with recovery of hepatic histology and functional alterations, compared to liraglutide treatment.

Application of Ultrasound as Clean Technology for Extraction of Specialized Metabolites From Stinging Nettle (Urtica dioica L.)

Nettle is a highly valued medicinal plant that is still largely neglected, both in terms of nutrition and use for pharmacological purposes. Tinctures, i.e., alcoholic extracts, are becoming increasingly popular nettle products, mainly because they allow better availability of phytochemicals and their stability over a longer period of time. The production of alcoholic extracts is a chemically demanding process that is still usually carried out using conventional techniques, which have numerous drawbacks. The use of green technologies such as ultrasound-assisted extraction (UAE), which is characterized by high efficiency of phytochemical extraction, shorter treatment time, and a much lower environmental footprint, is a suitable and sustainable solution. Therefore, the aim of this study is to determine the influence of the extraction method, conventional and ultrasound (by varying two ultrasound equipment systems), time and ethanol concentration on the extraction of specialized metabolites from nettle powder. Ultrasonic extraction using a probe system significantly contributed to increase the ascorbic acid yield, polyphenolic compounds, and antioxidant capacity of nettle extracts compared to conventional extraction. In addition, when a probe system was used during UAE, significantly less time was required for isolation of individual specialized metabolites compared to ultrasonic extraction in the bath. Ethanol concentration (50 and 80% v/v) also proved to be an important factor in the efficiency of extraction of specialized metabolites, with 80% ethanol being more effective for the isolation of ascorbic acid and pigment compounds (chlorophyll and carotenoids), while 50% v/v for the extraction of polyphenolic compounds. It can be concluded that extraction with the ultrasonic probe system is much more efficient in obtaining higher yields of specialized metabolites from nettle powder in a shorter time (average process duration 5-10 min) both compared to UAE in the bath and classical extraction. However, optimization of the key factors of time, solvent type, and ultrasonic power is necessary to maintain the nutritional quality of the nettle extract in order to obtain a final product with a high specialized metabolites content, antioxidant capacity, and functional value. The future application of alcoholic nettle extracts is based on the fact that these products have significant potential as functional foods and pharmacological preparations for the treatment of a number of but also to strengthen the immune system, mainly due to the rich nutritional composition and high content of various specialized metabolites. The prepared extracts can be safely taken orally by diluting the tinctures with water immediately before ingestion.

Production of hydroxytyrosol rich extract from Olea europaea leaf with enhanced biological activity using immobilized enzyme reactors

As olive leaves constitute the main by-product of the olive oil industry with important environmental and economic impact, there is an increasing demand for its valorization. In the present work, we report the development and application of immobilized enzyme batch bioreactors for the chemo-enzymatic treatment of an aqueous Olea europaea leaf extract rich in oleuropein to produce an extract enriched in hydroxytyrosol and other oleuropein hydrolysis products. To this end, a robust biocatalyst was developed through the immobilization of β-glucosidase on chitosan-coated magnetic beads which exhibited high hydrolytic stability after 240 h of incubation at 37 °C. The biocatalyst was successfully used in both a rotating bed-reactor and a stir-tank reactor for the modification of the olive leaf extract leading to high conversion yields of oleuropein (exceeding 90%), while an up to 2.5 times enrichment in hydroxytyrosol was achieved. Over 20 phenolic compounds (from different classes of phytochemicals such as flavonoids, secoiridoids, and their derivatives) were identified, in the extract before and after its modification through various chromatographic and spectroscopic techniques. Finally, the biological activity of both extracts was evaluated. Compared to the non-modified extract, the modified one demonstrated 20% higher antioxidant activity, seven-fold higher antibacterial activity, and enhanced cytotoxicity against leiomyosarcoma cells.

Comparative Evaluation of the Phytochemical Profiles and Antioxidant Potentials of Olive Leaves from 32 Cultivars Grown in China

Olives (Olea europaea L.) are a significant part of the agroindustry in China. Olive leaves, the most abundant by-products of the olive and olive oil industry, contain bioactive compounds that are beneficial to human health. The purpose of this study was to evaluate the phytochemical profiles and antioxidant capacities of olive leaves from 32 cultivars grown in China. A total of 32 phytochemical compounds were identified using high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry, including 17 flavonoids, five iridoids, two hydroxycinnamic acids, six triterpenic acids, one simple phenol, and one coumarin. Specifically, olive leaves were found to be excellent sources of flavonoids (4.92–18.29 mg/g dw), iridoids (5.75–33.73 mg/g dw), and triterpenic acids (15.72–35.75 mg/g dw), and considerable variations in phytochemical content were detected among the different cultivars. All tested cultivars were classified into three categories according to their oil contents for further comparative phytochemicals assessment. Principal component analysis indicated that the investigated olive cultivars could be distinguished based upon their phytochemical profiles and antioxidant capacities. The olive leaves obtained from the low-oil-content (<16%) cultivars exhibited higher levels of glycosylated flavonoids and iridoids, while those obtained from high-oil-content (>20%) cultivars contained mainly triterpenic acids in their compositions. Correspondingly, the low-oil-content cultivars (OL3, Frantoio selection and OL14, Huaou 5) exhibited the highest ABTS antioxidant activities (758.01 ± 16.54 and 710.64 ± 14.58 mg TE/g dw, respectively), and OL9 (Olea europaea subsp. Cuspidata isolate Yunnan) and OL3 exhibited the highest ferric reducing/antioxidant power assay values (1228.29 ± 23.95 mg TE/g dw and 1099.99 ± 14.30 mg TE/g dw, respectively). The results from this study may be beneficial to the comprehensive evaluation and utilization of bioactive compounds in olive leaves.

Optimization of Bioactive Phenolics Extraction and Cosmeceutical Activity of Eco-Friendly Polypropylene-Glycol-Lactic-Acid-Based Extracts of Olive Leaf

Olive leaf is a rich source of phenolic compounds with numerous activities related to skin health and appearance. In this study, a green extraction method was developed using eco-friendly solvents: polypropylene glycol (PPG), lactic acid (LA), and water. The optimal extraction conditions were established, including solvent, extraction time, technique (magnetic stirrer vs. ultrasound-assisted extraction), and herbal material/solvent ratio. The composition of the solvent mixture was optimized using a mixture design. The content of phenolic compounds, including oleuropein and verbascoside, was determined using high-performance liquid chromatography (HPLC) and spectrophotometric methods. Using different extraction conditions, three extracts were prepared and their phytochemical compositions and antioxidant and skin-related bioactivities were investigated. The extracts were excellent inhibitors of elastase, collagenase, tyrosinase, and lipoxygenase. The best activity was shown by the extract richest in phenolics and prepared using magnetic-stirrer-assisted extraction for 20 min, with 0.8 g of herbal material extracted in 10 mL of PPG/LA/water mixture (28.6/63.6/7.8, w/w/w), closely followed by the extract prepared using the same extraction conditions but with 0.42 g of herbal material. The investigated PPG/LA/water mixtures contributed to the overall enzyme-inhibitory activity of the extracts. The prepared extracts were appropriate for direct use in cosmetic products, thus saving the time and energy consumption necessary for the evaporation of conventional solvents.

Mycotoxin Interactions along the Gastrointestinal Tract: In Vitro Semi-Dynamic Digestion and Static Colonic Fermentation of a Contaminated Meal

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) naturally co-occur in several foods, but no studies have followed the fate of mycotoxins' interactions along the gastrointestinal tract using in vitro digestion models. This study used a novel semi-dynamic model that mimics gradual acidification and gastric emptying, coupled with a static colonic fermentation phase, in order to monitor mycotoxins' bioaccessibility by the oral route. AFB1 and OTA bioaccessibility patterns differed in single or co-exposed scenarios. When co-exposed (MIX meal), AFB1 bioaccessibility at the intestinal level increased by ~16%, while OTA bioaccessibility decreased by ~20%. Additionally, a significant increase was observed in both intestinal cell viability and NO production. With regard to mycotoxin-probiotic interactions, the MIX meal showed a null effect on Lactobacillus and Bifidobacterium strain growth, while isolated AFB1 reduced bacterial growth parameters. These results were confirmed at phylum and family levels using a gut microbiota approach. After colonic fermentation, the fecal supernatant did not trigger the NF-kB activation pathway, indicating reduced toxicity of mycotoxins. In conclusion, if single exposed, AFB1 will have a significant impact on intestinal viability and probiotic growth, while OTA will mostly trigger NO production; in a co-exposure situation, both intestinal viability and inflammation will be affected, but the impact on probiotic growth will be neglected.

Mechanical damage and thermal effect induced by ultrasonic treatment in olive leaf tissue. Impact on polyphenols recovery

The influence of ultrasound treatment (US) on cellular damage of olive leaf tissue was studied. Mechanical damage and thermal effect of US were characterized. The level of tissue damage was defined by the diffusivity disintegration index Z_D based on the diffusivity of solutes extracted from olive leaves differently treated. The Arrhenius form using the temperature dependences of the thermal treatment time within the temperature interval 20-90 °C was observed for the thermal process. The corresponding activation energy ΔUT was estimated as 57 kJ/mol. The temperature dependences of electrical conductivity were measured for extracts of intact and maximally treated olive leaves. Then the diffusivity disintegration index Z_D and total phenolic compounds recovery for three studied US powers were calculated (100, 200, and 400 W). The results evidenced that the mechanically stimulated damage in olive leaf tissue can occur even at a low US power of 100 W if treatment time is long enough (t = 3.5 h). The US treatment noticeably accelerated the diffusion process mechanically in addition to its thermal effect. Trials in aqueous solution revealed the dependence of polyphenols extraction on damage level with respect to the US power applied.

Valorization of Fig (Ficus carica L.) Waste Leaves: HPLC-QTOF-MS/MS-DPPH System for Online Screening and Identification of Antioxidant Compounds

Fig (Ficus carica L.) leaves are produced each year and often disposed, resulting in a waste of resources. Fig waste leaves are rich in flavonoids, which have strong antioxidant activity; however, the variety and chemical structure of antioxidants in fig leaves have not been reported in detail. To take full advantage of fig waste leaves, antioxidant capacity of different extracts (petroleum ether, ethyl acetate, and water) was evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and ferric-ion-reducing antioxidant power (FRAP) methods. The results showed that flavonoids in ethyl acetate extraction had the highest content (83.92 ± 0.01 mg/g), maximum DPPH scavenging activity (IC₅₀ 0.54 mg/mL), highest ABTS scavenging rate (80.28%), and FRAP (3.46 mmol/g). Furthermore, an HPLC-QTOF-MS/MS-DPPH method was developed to identify 11 flavonoids in fig waste leaves. This rapid and efficient method can not only be used for screening the antioxidant components in fig waste leaves, but also can be combined with mass spectrometry to identify the compounds with antioxidant capacity. There are three flavonoids with significant antioxidant capacity, which are 3-O-(rhamnopyranosyl-glucopyranosyl)-7-O-(glucopyranosyl)-quercetin, isoschaftoside, and rutin. The results confirmed that fig waste leaves contain a variety of antioxidant components, which contributed to increase the value of fig waste leaves as antioxidants.

Valorization of Wastewater from Table Olives: NMR Identification of Antioxidant Phenolic Fraction and Microwave Single-Phase Reaction of Sugary Fraction

The table olive industry is producing a huge amount of wastewater, which is a post-processing cost and an environmental concern. The present study aims to valorize this processing by-product to obtain a value-added product, thereby enhancing resource efficiency and contributing to achieving sustainable development goals (SDGs). In this sense, a chemical reaction-based platform was developed to obtain valuable components, such as levulinic acid (LA) and 5-hydromethylfurfural (HMF). The products were then analyzed using NMR identification of the antioxidant phenolic fraction and microwave single-phase reaction of the sugary fraction. According to the results, the highest concentration of phenolic compounds does not correspond to the sample directly obtained from NaOH treatment (S1), indicating that water washing steps (S2–S5) are fundamental to recover phenolic substances. Moreover, glucose was presented in the sugary fraction that can be transformed into levulinic acid by a single-phase reaction under microwave irradiation. The information provided in this manuscript suggests that the wastewater from the olive processing industry can be valorized to obtain valuable products.

Environmental friendly extraction of walnut bark-based juglone natural colorant for dyeing studies of wool fabric

Environmental friendly products particularly natural dyes are going to be much popular around the globe due to their non-toxic and bio-degradable nature. The current study was planned to enhance the dyeability of walnut bark having juglone as a reddish-brown natural dye under ultrasonic radiation as an environment-friendly and green tool After conducting series of experiments, it has been found that wool (RW) and extract (RE) after ultrasonic treatment for 45 min, when dyed for 45 min at 55°C using an acidic bath of 3 pH has given good color strength on the wool fabric. To develop the new shades, sustainable and eco-label chemicals (Fe, Al, and tannic acid) and four bio-mordants such as Acacia bark, Turmeric, Henna, and Pomegranate were also applied at optimum conditions. It is studied that 3% of turmeric extract as pre-bio-mordant and 5% of Acacia extract as post-bio-mordant has given excellent color characteristics as compared to their synthetic. It is concluded that ultrasonic treatment being an eco-friendly tool has a great potential to improve the dyeability of natural reddish-brown dye from walnut bark and the inclusion of sustainable biosources as a color modifier has value-added the natural dyeing process with excellent color ratings.

Natural Antioxidants from Endemic Leaves in the Elaboration of Processed Meat Products: Current Status

During the last few years, consumers' demand for animal protein and healthier meat products has increased considerably. This has motivated researchers of the meat industry to create products that present healthier components while maintaining their safety, sensory characteristics, and shelf life. Concerning this, natural plant extracts have gained prominence because they can act as antioxidants and antimicrobials, increasing the stability and shelf life of processed meat products. It has been observed that the leaves of plant species (Moringa oleifera, Bidens pilosa, Eugenia uniflora, Olea europea, Prunus cerasus, Ribes nigrum, etc.) have a higher concentration and variety of polyphenols than other parts of the plants, such as fruits and stems. In Chile, there are two native berries, maqui (Aristotelia chilensis) and murtilla (Ugni molinae Turcz), that that stand out for their high concentrations of polyphenols. Recently, their polyphenols have been characterized, demonstrating their potential antioxidant and antimicrobial action and their bioactive action at cellular level. However, to date, there is little information on their use in the elaboration of meat products. Therefore, the objective of this review is to compile the most current data on the use of polyphenols from leaves of native plants in the elaboration of meat products and their effect on the oxidation, stability, and organoleptic characteristics during the shelf life of these products.

Plant cell cultures of Nordic berry species: Phenolic and carotenoid profiling and biological assessments

Plant cell cultures from cloudberry (CL), lingonberry (LI), stone berry (ST), arctic bramble (AB), and strawberry (SB) were studied in terms of their polyphenol and carotenoid composition, antioxidant activity, antihemolytic activity and cytotoxicity effects on cancerous cells. High-resolution mass spectrometry data showed that LI, presented the highest antioxidant activity, contained the highest contents of flavones, phenolic acids, lignans, and total carotenoids, while CL, ST and SB presented the opposite behavior. AB and SB presented the lowest FRAP and CUPRAC values, while AB and CL presented the lowest reducing power. SB presented the lowest antioxidant activity measured by single electron transfer assays and the lowest content of lignans, phenolic acids, and flavones. CL and LI decreased the viability of in vitro mammary gland adenocarcinoma while only LI decreased the viability of in vitro lung carcinoma and showed protective effects of human erythrocytes against mechanical hemolysis.

Metabolomics-Guided Elucidation of Plant Abiotic Stress Responses in the 4IR Era: An Overview

Plants are constantly challenged by changing environmental conditions that include abiotic stresses. These are limiting their development and productivity and are subsequently threatening our food security, especially when considering the pressure of the increasing global population. Thus, there is an urgent need for the next generation of crops with high productivity and resilience to climate change. The dawn of a new era characterized by the emergence of fourth industrial revolution (4IR) technologies has redefined the ideological boundaries of research and applications in plant sciences. Recent technological advances and machine learning (ML)-based computational tools and omics data analysis approaches are allowing scientists to derive comprehensive metabolic descriptions and models for the target plant species under specific conditions. Such accurate metabolic descriptions are imperatively essential for devising a roadmap for the next generation of crops that are resilient to environmental deterioration. By synthesizing the recent literature and collating data on metabolomics studies on plant responses to abiotic stresses, in the context of the 4IR era, we point out the opportunities and challenges offered by omics science, analytical intelligence, computational tools and big data analytics. Specifically, we highlight technological advancements in (plant) metabolomics workflows and the use of machine learning and computational tools to decipher the dynamics in the chemical space that define plant responses to abiotic stress conditions.

Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea, Rosemary, Clove, and Oregano

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.

Ultrasound as a Promising Tool for the Green Extraction of Specialized Metabolites from Some Culinary Spices

Spices are a popular food of plant origin, rich in various phytochemicals and recognized for their numerous properties. The aim of the study was to evaluate the antioxidant and antimicrobial activity, as well as the content of specialized metabolites, of aqueous extracts of three spice species--garlic (Allium sativum L.), ginger (Zingiber officinalle L.) and turmeric (Curcuma longa L.)--prepared by green extraction methods. Ultrasound treatment increased the chromaticity parameter b value of turmeric and ginger extracts, thus indicating a higher yellow color predominantly due to curcuminoids characteristic of these species. Ultrasound-assisted extraction significantly increased the content of total soluble solids, phenolic compounds, total carotenoids and vitamin C. The temperature of the system was also an important factor, with the highest (70 °C) conditions in ultrasound-assisted extraction having a positive effect on thermolabile compounds (vitamin C, phenolics, total carotenoids). For example, turmeric extract treated with ultrasound at 70 °C had up to a 67% higher vitamin C content and a 69.4% higher total carotenoid content compared to samples treated conventionally at the same temperature, while ginger extracts had up to 40% higher total phenols. All different concentrations of spice extracts were not sufficient for complete inhibition of pathogenic bacterial strains of Salmonella, L. monocytogenes and S. aureus; however, only garlic extracts had an effect on slowing down the growth and number of L. monocytogenes colonies. Spice extracts obtained by ultrasonic treatment contained a significantly higher level of bioactive compounds and antioxidant capacity, suggesting that the extracts obtained have significant nutritional potential and thus a significant possibility for phytotherapeutic uses.

Optimization of ultrasound-assisted aqueous two phase extraction of polyphenols from olive leaves

In this study, polyphenols from olive leaves was extracted by ultrasound-assisted aqueous two phase extraction (UAATPE). Based on single factor experiment and response surface methodology (RSM), the optimum extraction conditions of polyphenols contained 29% (w/w) (NH₄)₂SO₄, 35% (w/w) ethanol, pH 6.7, and 45 °C. The maximum extraction yield of polyphenols and oleuropein content were 34.06 mg/g and 44.13 mg/L, respectively. Compared with ultrasound-assisted extraction (UAE) and aqueous two phase extraction (ATPE), the extraction yield of polyphenols by UAATPE was 9.48 and 61.19% higher, respectively. In addition, the extract of UAATPE had higher purity. The results of antioxidant activity showed that polyphenols extracted by UAATPE had stronger DPPH and hydroxyl radicals scavenging ability and reducing power. Therefore, UAATPE is an efficient method for extracting polyphenols from olive leaves.

Effect of Ultrasound on In Vitro Bioaccessibility of Phenolic Compounds and Antioxidant Capacity of Blackberry (Rubus fruticosus) Residues cv. Tupy

Agro-industries residues of fruit are a source of antioxidant compounds with a possible health impact. The aim of this study was to evaluate the total phenolic content (TPC), total monomeric anthocyanins (TMA), individual phenolic compounds (IPC), antioxidant capacity and in vitro intestinal bioaccessibility from blackberry residues (BR), and ultrasonicated blackberry residues (US-BR). The results showed that BR had higher TPC (4,016.43 mg GAE/100 g DM), TMA (364.53 mg Cy-3-Gl/100 g) antioxidant capacity by ABTS (5,422.38 mg AAE/100 g DM) and FRAP (12511.44 μmol Fe(II)/100 g DM) than US-BR. TPC and TMA obtained by US-BR were more bioaccessible (70 and 51%, respectively) compared to BR (37 and 34%, respectively). The use of ultrasound can aid the extraction of total phenolic compounds and improve their bioaccessibility. After acid hydrolysis, a high amount of individual phenolic compounds (IPC) in US-BR (chlorogenic acid, caffeic acid, apigenin, luteolin and kaempferol) was obtained compared with BR. Before in vitro digestion, total individual compounds (TIC) content was lower in the BR (29.49 mg/100 g DM) than US-BR (92.36 mg/100 g DM) and there was 5 and < 1%, respectively. Therefore, the food industry would use residues of blackberry fruits as a source of antioxidant compounds with possible health benefits.

Optimization of a Green Ultrasound-Assisted Extraction of Different Polyphenols from Pistacia lentiscus L. Leaves Using a Response Surface Methodology

Pistacia lentiscus leaves are used in several applications, thanks to their polyphenolic abundance. Thiswork aimed to characterize the polyphenols and to optimize the extraction conditions to shorten the time, decrease the consumption of solvent, and to maximize the yield of different classes of phenolics, which have diverse industrial applications. The variables were optimized by applying a Box-Behnken design. Galloyl and myricetin derivatives were the most abundant compounds, and two new tetragalloyl derivatives were identified by LC-MS/MS. According to the models, the maximum yields of polyphenols (51.3 ± 1.8 mg g-1 DW) and tannins (40.2 ± 1.4 mg g-1 DW) were obtained using 0.12 L g-1 of 40% ethanol at 50 °C. The highest content of flavonoids (10.2 ± 0.8 mg g-1 DW) was obtained using 0.13 L g-1 of 50% ethanol at 50 °C, while 0.1 L g-1 of 30% ethanol at 30 °C resulted in higher amounts of myricitrin (2.6 ± 0.19 mg g-1 DW). Our optimized extraction decreased the ethanolic fraction by 25% and halved the time compared to other methods. These conditions can be applied differently to obtain P. lentiscus extracts richer in tannins or flavonoids, which might be employed for various purposes.

Bacterial growth and biological properties of Cymbopogon schoenanthus and Ziziphus lotus are modulated by extraction conditions

The present study aims to evaluate the antibacterial activity and biological properties of two traditional Saharian plants (Cymbopogon schoenanthus and Ziziphus lotus). The plant extracts were obtained by using a different combination of extraction methods (conventional vs. ultrasound-assisted) and solvents (water vs. ethanol:water (50:50, v/v)). The antioxidant profile, anti-inflammatory activity and impact on bacterial growth (foodborne and probiotic bacteria) of the obtained extracts were assessed. The plant species showed the hierarchically more important role in determining the biological properties of the extracts, followed by extraction solvent and extraction conditions. Conventional Z. lotus hydroethanolic extracts showed the highest total phenolic content (20.4 mg GAE/g), while Z. lotus ethanol extracts from ultrasound-assisted process presented the highest content of carotenoids (0.15 mg/g). In addition, ultrasound-assisted Z. lotus hydroethanolic extracts presented the highest in vitro radical scavenging activity, being 7.93 mmol Trolox/g. Multivariate analysis statistics (PCA) showed that both the extraction methodology and the solvent used strongly affected the bacterial growth. Z. lotus mainly decreased the growth rate of S. aureus and L. innocua. Interestingly, the aqueous extracts of this plant as well as those from C. schoenanthus, obtained by conventional extraction, significantly increased the growth rate and the maximal optical density of L. casei. Aqueous extracts of both Z. lotus and C. schoenanthus slightly influenced the growth of Bifidobacterium. Overall, the extracts of these plants showed selective activities with respect to pathogens and probiotic bacteria and may provide an advantage both in terms of antimicrobial and prebiotic activity.