Evaluation of total antioxidant potential of Pistacia lentiscus var. chia leaves extracts using UHPLC–HRMS

Recent advances in methods of extraction, pre-concentration, purification, identification, and quantification of kaempferol

As a naturally widely-occurring dietary, cosmetic, and therapeutic flavonoid, kaempferol has gained much consideration for its nutritional and pharmaceutical properties in recent years. Although there have been performed a high number of studies associated with different aspects of kaempferol's analytical investigations, the lack of a comprehensive summary of the various methods and other plant sources that have been reported for this compound is being felt, especially for many biological applications. This study, aimed to provide a detailed compilation consisting of sources (plant species) and analytical information that was precisely related to the natural flavonoid (kaempferol). There is a trend in analytical research that supports the application of modern eco-friendly instruments and methods. In conclusion, ultrasound-assisted extraction (UAE) is the most general advanced method used widely today for the extraction of kaempferol. During recent years, there is an increasing tendency towards the identification of kaempferol by different methods.

Evaluation of Phytochemical Content and In Vitro Antioxidant Activities of Pistacia lentiscus L. Leaves Extracts, a Medicinal Plant From the Beni-Snassen Forest (Eastern Region of Morocco)

A medicinal plant from the Beni-Snassen Forest in the eastern region of Morocco has been studied. This scientific research was carried out to measure the content of essential phytochemical constituents and their antioxidant capacities from the hydromethanolic extract of leaves of Pistacia lentiscus L. located on sites at varying levels of altitudes. Our results have shown that at the lowest altitude, there was a height significant (p ≤ 0.05) in the content of flavonoids and polyphenols. On the other hand, the ascorbic acid, chlorophylls, and tannins had a higher content concentration on sites with high altitudes. Analysis correlation shows a hight correlation between the DPPH and the polyphenols content. A correlation between the total antioxidant activity and flavonoid content was found to have many similarities. The results indicated that P. lentiscus L. leaves have significant sources of chemical compounds that might be employed for various purposes.

The Phenolic Content of Pistacia lentiscus Leaf Extract and Its Antioxidant and Antidiabetic Properties

The aims of this study were to determine the polyphenolic profile, to estimate the total phenolic and flavonoid contents, and to evaluate the antioxidant and antidiabetic activities of the extract of Pistacia lentiscus leaves, and the hydroacetonic mixture was employed as an alternative for common solvents in the extraction process. In order to explain the antidiabetic activity, molecular docking has been performed on the main constituents of the leaf extract. The characterization of the extract has been performed by high-performance liquid chromatography (HPLC) leading to the detection of 20 compounds of which gallic acid, ellagic acid, catechin, kaempferol, and quercetin 3-glucoside were identified using authentic standards. The total phenolic and flavonoid contents, assessed using the Folin-Ciocalteu and quercetin methods, were 394.5 ± 0.08 mg gallic acid equivalent/g dry extract (mg GAE/g DE) and 101.2 ± 0.095 mg quercetin equivalent/g dry extract (mg QE/g DE), respectively. On the other hand, the antioxidant activity of leaf extract, quantified by determining the ability to neutralize the free radical DPPH and β-carotene/linoleate model system, reached the values of 0.0027 ± 0.002 mg/mL and 0.128 ± 0.04 mg/mL, respectively. Regarding the antidiabetic activity, based on the inhibition of pancreatic α-amylase activity, a significant inhibition of about 68.20% with an IC50 value of 0.266 mg/mL had been observed. This finding is consistent with the molecular docking study of the main phenolic compounds of the extracts, where a remarkable binding affinity against α-amylase was observed, with values of -7.631 (kcal/mol), -6.818 (kcal/mol), and -5.517 (kcal/mol) for the major compounds catechin, quercetin-3-glucoside, and gallic acid, respectively.

Occurrence of Luteolin in the Greek Flora, Isolation of Luteolin and Its Action for the Treatment of Periodontal Diseases

Higher plants possess the ability to synthesize a great number of compounds with many different functions, known as secondary metabolites. Polyphenols, a class of flavonoids, are secondary metabolites that play a crucial role in plant adaptation to both biotic and abiotic environments, including UV radiation, high light intensity, low/high temperatures, and attacks from pathogens, among others. One of the compounds that has received great attention over the last few years is luteolin. The objective of the current paper is to review the extraction and detection methods of luteolin in plants of the Greek flora, as well as their luteolin content. Furthermore, plant species, crop management and environmental factors can affect luteolin content and/or its derivatives. Luteolin exhibits various biological activities, such as cytotoxic, anti-inflammatory, antioxidant and antibacterial ones. As a result, luteolin has been employed as a bioactive molecule in numerous applications within the food industry and the biomedical field. Among the different available options for managing periodontitis, dental care products containing herbal compounds have been in the spotlight owing to the beneficial pharmacological properties of the bioactive ingredients. In this context, luteolin's anti-inflammatory activity has been harnessed to combat periodontal disease and promote the restoration of damaged bone tissue.

P2X7-Receptor Pathway Involvement in the Anti-Inflammatory Activity of Medicinal Plants

Medicinal plants used in European folk medicine attached to Lamiales, Gentianales or Asterales orders are used to treat inflammatory disorders. Many targets have been identified but to date, implication of purinergic receptor P2X7 activation has not yet been investigated. We managed to evaluate the protective effect on P2X7 activation by plant extracts used as anti-inflammatory in European folk medicine by the YO-PRO-1 uptake dye in vitro bioassay. Results revealed that among our selected plants, species from Scrophularia and Plantago genus were able to decrease significantly P2X7 activation (>50 % at 0.1 and 1 μg/mL). UPLC/MS, dereplication and metabolomic analysis of Scrophularia extracts, allowed us to identify the cinnamoyl-iridoid harpagoside as putative inhibitor of P2X7 activation. These results open a new research field regarding the anti-inflammatory mechanism of cinnamoyl-iridoids bearing plants, which may involve the P2X7 receptor.

A Review of Pistacia lentiscus Polyphenols: Chemical Diversity and Pharmacological Activities

Pistacia lentiscus (lentisk) is a plant species of the Anacardiaceae family. It is a medicinal plant that grows wild in the Mediterranean region. This review aims to update the existing knowledge regarding P. lentiscus polyphenols by consulting references dated from 1996 to 2022. The data are organized and analyzed as follows: (i) to show the chemical diversity of phenolic products from P. lentiscus; (ii) to summarize the variability in phenolic composition and quantity; this could be attributed to plant origin, environmental conditions, phenological stage, and the polarity of the extraction solvents; (iii) to present the pharmacological properties in agreement with the traditional uses of this plant; and (iv) to demonstrate the correlation between the chemical profile and the pharmacological effect. Various compositions were observed, including phenolic acids, flavonoid glycosides, anthocyanins, catechins, and their derivatives. The biological and therapeutic potentials of lentisk extracts have been evaluated in terms of antioxidant, antimicrobial, and anti-inflammatory activities. Most of these activities are related to the phenolic composition of this plant. The content of this review will undoubtedly contribute to the choice of techniques for isolating the different bioactive molecules contained in the P. lentiscus. It is also of significance for the potential development of a micro-industrial sector based on the valorization of lentisk polyphenols.

Phytochemical Screening, and In Vitro Evaluation of the Antioxidant and Dermocosmetic Activities of Four Moroccan Plants: Halimium antiatlanticum, Adenocarpus artemisiifolius, Pistacia lentiscus and Leonotis nepetifolia

In this study, four Moroccan plants, Halimium antiatlanticum, Adenocarpus artemisiifolius, Pistacia lentiscus and Leonotis nepetifolia, were evaluated for their phytoconstituents and biological activities. Methanolic extracts of these plants were obtained by Soxhlet apparatus, phytochemical screening was performed, and the total phenolic and flavonoid contents were determined. Then, the antioxidant and dermocosmetic activities of the methanolic extracts were evaluated. The obtained results revealed that the leaves and/or aerial parts contained tannins, polyphenols, flavonoids, coumarins, carotenoids, terpenoids and saponins. The higher total phenolic content values were recorded on Pistacia lentiscus and Halimium antiatlanticum with 396.64 ± 30.79 and 304.96 ± 55.61 mgGAE/gDW, respectively. The antioxidant activity was measured by DPPH, ABTS and FRAP assays, and showed that Pistacia lentiscus and Halimium antiatlanticum were the most active extracts, with, respectively, IC50 values of 3.705 ± 0.445 and 5.037 ± 0.122 µg/mL for DPPH. The same results were observed for the FRAP and ABTS assays. Those extracts also showed a strong collagenase inhibitory activity at 200 µg/mL, with 78.51 ± 2.27% for Pistacia lentiscus and 73.10 ± 8.52% for Halimium antiatlanticum. Adenocarpus artemisiifolius showed the highest elastase inhibition rate, with 76.30 ± 5.29%. This study disclosed the dermocosmetic potential of Halimium antiatlanticum and Adenocarpus artemisiifolius, two Moroccan endemic plants that can be traditionally used by local populations or exploited by the cosmetic industry.

Apoptotic, Anti-Inflammatory Activities and Interference with the Glucocorticoid Receptor Signaling of Fractions from Pistacia lentiscus L. var. chia Leaves

In this study acetonic extracts of leaves of Pistacia lentiscus L. var. chia (mastiha tree) grown in the south as well as in the north Chios Greek island were isolated and further fractionated to give three different polarity fractions: apolar, medium-polar, and polar. The isolated fractions were assessed as regards their main composition, cytotoxic, anti-inflammatory activities, and interference with the glucocorticoid receptor (GR) signaling, applying cytotoxic assay, luciferase assays, and Western blot analysis of apoptosis-, energy-, and inflammation-associated molecules. Differences in cell viability have been detected among different polarity leaf fractions as well as among fractions of different plant origin with polar fractions showing the highest cytotoxicity. Fractions-induced anti-inflammatory activities and suppressive effects on the dexamethasone (DEX)-induced GR transcriptional activation were unveiled. The partition protocol of leaves fractions applied uncovers the enhanced glucocorticoid-associated biological activities of the medium-polar fractions, which may be associated with their enrichment in the triterpenoids that showed structural similarity with the glucocorticoids. A reduction in GR protein levels is observed by the fraction which is shown to be associated with the medium polar-induced proteolytic degradation of the receptor. In addition, the enhanced cytotoxic, anti-inflammatory, and potential anti-glycemic activities of the fractions from the Southern P. lentiscus L. that exclusively produce the mastiha resin, is revealed, indicating that leaves fractions from mastiha tree, similarly to mastiha tree resin, may have the potential to be further analyzed for their potent applications in the pharmaceutical cosmetic and nutraceutical fields.

Chemical and Biological Evaluation of the Oil and Seedcake from Seeds of a Greek Cardoon Cultivar as Potential Functional Vegetable Oil. Comparison with Sesame, Flaxseed and Extra Virgin Olive Oils

Cynara cardunculus L. is a plant of the Mediterranean basin, known since antiquity as a food and for its therapeutic properties. The needs of the 21st century for the utilization of agricultural waste has led to the study of the seed oil of a Greek cultivar of Cynaracardunculus (GCCC) as potential nutritional oil, as large amounts of cardoon seeds are discarded. The sterol and fatty acid profile of cold-pressed seed oil was examined by gas chromatography-mass spectrometry GC-MS and compared with that of solvent extraction. Total phenolic content was determined and compared with well-known and widely appreciated edible vegetable oils; while, additionally, the total lignan content and nutritional value of cold-pressed oil revealed it as a potential dietary candidate. Furthermore, the seedcake (residue of cold-pressed oil extraction) has been studied exerting it as a good source of phenolics. Both GCCC oil and seedcake were tested for their antioxidant and enzyme inhibitory activities exhibiting higher activity compared to the sesame, flaxseed and extra virgin olive oils. According to the results, Cynara seed oil was shown to be a rich source of ω-6/-9 fatty acids and phenolics, highlighting, indicating that it could be a promising health-promoting vegetable oil, while the seedcake was revealed as a rich source of bioactive compounds.

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.

Evaluation of Polyphenolic Profile and Antioxidant Activity of Pistacia lentiscus L. Leaves and Fruit Extract Obtained by Optimized Microwave-Assisted Extraction

Pistacia lentiscus L. is a Mediterranean shrub known for its health promoting effects attributed to a large extent to polyphenols accumulated in all parts of the plant. Microwave-assisted extraction is a green extraction technique enabling fast and effective isolation of plant polyphenols. Therefore, the aim of this research was to optimize the microwave-assisted extraction of polyphenols from Pistacia lentiscus L. leaves and fruit in terms of temperature, extraction time and microwave power and to evaluate their polyphenolic profile by UPLC/ESI-MS2 and antioxidant capacity by ORAC assay. Optimal extraction conditions for leaf polyphenols were 69 °C, 512 W and 12 min, while for fruit were slightly more intensive-75 °C, 602 W and 15 min. Obtained total phenolic content in leaves and fruit was similar to that obtained after 30 min of the heat-reflux method. The polyphenolic profile of extracts included 34 compounds, with myricetin glycosides being the most abundant compounds among flavonoids in Pistacia lentiscus L. leaves and fruit and gallic acid and its derivates among the phenolic acids. ORAC assay showed higher antioxidant capacity for Pistacia lentiscus L. leaves extract than for fruit, which is in correlation with their respective phenolic content.

Determination of Phenolic Compounds’ Extraction Conditions from Pistacia palaestina Leaves at Two Different Stages of Maturity

Background:

Phenolic compounds are distributed throughout the plant kingdom. Numerous investigations have proved that Pistacia species have secondary metabolites, and these contain different classes of bioactive phenolic compounds.

Objective:

The objective of the present work was to optimize the extraction conditions of phenolic compounds from Pistacia palaestina leaves cultivated in Syria and find out the effects of the solvent type, extraction time, and temperature on total phenolic content (TPC) and in vitro antioxidant activity% (AA%). Two different growth stages were studied.

Methods:

Antioxidant activity and total phenolic content values were estimated using 2,2’-diphenyl- 1-picrylhydrazyl and Folin-Ciocalteu methods, respectively.

Results:

The highest TPC and AA% were found in fresh leaves (14.32g/100g and 92.69%, respectively). The optimum extraction solvent for phenolic recovery and antioxidant capacity was acetone 40%. Changes both in temperature (25, 40, 60 and 80°C) and time (15, 30, 45 and 60 min) had no significant influence on TPC and AA% of Pistacia extracts.

Conclusion:

Phenolic compounds could be extracted in a short time at a low temperature and could be used as natural antioxidant agents.

Kainari, a Unique Greek Traditional Herbal Tea, from the Island of Lesvos: Chemical Analysis and Antioxidant and Antimicrobial Properties

The chemical composition, as well as the total phenolic content (TPC) and the potential antioxidant and antimicrobial activity, of three Kainari-herbal tea samples from different areas of Lesvos Island (Greece) was evaluated. The rich aroma of the mixtures was studied through GC-MS, as well as through Headspace Solid-Phase Microextraction (HS-SPME)/GC-MS analyses. Cinnamon, clove, nutmeg, pepper, and ginger were identified as main ingredients, while, throughout the chemical analysis of the volatiles of one selected sample, several secondary metabolites have been isolated and identified on the basis of GC-MS as well as spectral evidence as eugenol, cinnamic aldehyde and myristicin, cinnamyl alcohol, alpha-terpinyl acetate, and β-caryophyllene. Furthermore, two food dyes, azorubine and amaranth, were also isolated and identified from the infusions. The total phenolic content was estimated and the free radical scavenging activity was determined by DPPH and ABTS assays and the antimicrobial activity of the extracts was tested showing a very interesting profile against all the assayed microorganisms. Due to its very pleasant aroma and taste properties as well as to its bioactivities, Kainari-herbal tea could be further proposed as functional beverage.

Evaluation of Phenolic Compounds in Cistus creticus Bee Pollen from Greece. Antioxidant and Antimicrobial Properties

This study was carried out to evaluate the antioxidant properties of Greek endemic Cistus creticus L. (rock rose) bee pollen and define its phenolic compounds. In the framework of our scientific studies on Greek bee keeping products, we report herein our research on three Greek bee pollen samples from Cistus. Their pollinic spectra were obtained by Louveaux's quantitative microscopical analysis and it showed that one of them had Cistus sp. (Cistaceae) as abundant pollen (together with low percentage of Brassica sp. (Cruciferae). Throughout the chemical analysis of the extracts, several secondary metabolites of flavonoid structure have been identified as major components. Specifically, quercetin-7-rhamnoside (1), quercetin-3-neohesperidoside (2), kaempferol-3-neohesperidoside (3), myricetin-3-neohesperidoside (4), kaempferol-3-glucoside (5) and quercetin-3-glucoside (6) have been isolated and their structures were elucidated on the basis of spectral evidence. Moreover, the total phenolic and flavonoid content was estimated and the free radical scavenging activity was determined by DPPH and ABTS assays. The antimicrobial activity of the extracts was tested against six Gram-positive and -negative bacteria and three pathogenic fungi, and the butanol extract showed a very interesting broad antimicrobial profile (MIC 1.98•10−3 - 2.98•10−3 mg/ml) against all the assayed microorganisms.

Comprehensive characterization and identification of antioxidants in Folium Artemisiae Argyi using high-resolution tandem mass spectrometry

Antioxidants from natural sources, such as vegetables and fruits, are attracting more and more interest. In this work, we evaluated the antioxidant potential of Folium Artemisia Argyi, a traditional Chinese herb medicine and food supplement. The total phenolic content, total flavonoid content, and antioxidant ability of the crude extracts and fractions obtained from consecutively partition of n-hexane, ethyl acetate, and n-butanol were measured and compared. Ethyl acetate fraction shows the highest total phenolic and flavonoid contents and highest antioxidant capability with regard to DPPH, ABTS, superoxide anion free radical scavenging ability, and ferric-reducing antioxidant power. In addition, the potential antioxidant components were screened by DPPH-UHPLC-MS experiments and subsequently characterized by using high-resolution tandem mass spectrometry. This work finally identified 45 antioxidants, including organic acids, phenolic compounds, flavonoids, and methoxylated flavonoids. The results suggested that Folium Artemisiae Argyi is a potential inexpensive resource of natural antioxidants.