Antioxidant activity of different parts of Pistacia khinjuk Stocks fruit and its correlation to phenolic composition

The fruits of Pistacia khinjuk Stocks were collected from Ilam province, Iran. The aim of this study was to analyse antioxidant capacity and phenolic composition of different parts of P. khinjuk fruit. The antioxidant capacity of extracts was measured using different assays: ferric reducing ability of plasma, 2,2-diphenyl-1-picrylhydrazyl and nitric oxide radical scavenging. The phenolic composition of P. khinjuk fruit is reported for the first time. Amongst different parts of the fruit analysed in this study, hull extract contained the highest total phenolic and flavonoid contents. We observed a high correlation between different antioxidant activity and total phenolic and flavonoid contents. Therefore, antioxidant capacity can be related to total phenolic and flavonoid contents. A correlation analysis revealed that ascorbic acid, gallic acid, rutin, caffeic acid, ferulic acid and sinapic acid were the phenolic compounds mainly responsible for antioxidant power of the fruit extracts.     

Antioxidant capacities and total phenolic contents increase with gamma irradiation in two types of Malaysian honey

Two types of monofloral Malaysian honey (Gelam and Nenas) were analyzed to determine their antioxidant activities and total phenolic and flavonoid contents, with and without gamma irradiation. Our results showed that both types of honey can scavenge free radicals and exhibit high antioxidant-reducing power; however, Gelam honey exhibited higher antioxidant activity (p < 0.05) than Nenas honey, which is in good correlation (r = 0.9899) with its phenolic contents. Interestingly, we also noted that both irradiated honeys have higher antioxidant activities and total phenolic and flavonoid contents compared to nonirradiated honeys by Folin-Ciocalteu and UV-spectrophotometry methods, respectively. However, HPLC analysis for phenolic compounds showed insignificant increase between irradiated and nonirradiated honeys. The phenolic compounds such as: caffeic acid, chlorogenic acid, ellagic acid, p- coumaric acid, quercetin and hesperetin as indicated by HPLC method were found to be higher in Gelam honey versus Nenas honey. In conclusion, irradiation of honey causes enhanced antioxidant activities and flavonoid compounds.     

Antioxidant activities and polyphenolic contents of three selected Micromeria species from Croatia

Antioxidant activities of three selected Micromeria species growing in Croatia (M. croatica, M. juliana and M. thymifolia) were evaluated using five different antioxidant assays, in comparison with plant polyphenolic constituents and reference antioxidants. All studied ethanolic extracts exhibited considerable activity to scavenge DPPH and hydroxyl free radicals, reducing power, iron chelating ability and total antioxidant capacity in the order: M. croatica > M. juliana > M. thymifolia. Total polyphenol (9.69-13.66%), phenolic acid (5.26-6.84%), flavonoid (0.01-0.09%) and tannin (3.07-6.48%) contents in dried plant samples were determined spectrophotometrically. A strong positive correlation between antioxidant activities and contents of phenolic acids and tannins was found, indicating their responsibility for effectiveness of tested plants. Our findings established Micromeria species as a rich source of antioxidant polyphenols, especially the endemic M. croatica.     

Chemical composition and antioxidant activities of essential oils and methanol extracts of three wild Lavandula L. species

A comparative study of essential oil composition, polyphenol content and antioxidant activities of Lavandula coronopifolia, Lavandula multifida and Lavandula stoechas subsp. stoechas were reported. Qualitative and quantitative variations in the composition of oils according to species were shown. Lavandula coronopifolia's oil was characterised by high proportions of trans-β-ocimene (26.9%), carvacrol (18.5%), β-bisabolene (13.1%) and myrcene (7.5%). The main components of L. multifida oil are carvacrol (65.1%) and β-bisabolene (24.7%). Lavandula stoechas oil is rich in fenchone (34.3%) and comphor (27.4%). The total phenolic and flavonoid contents also significantly varied among species. Lavandula coronopifolia exhibits the highest phenolic and flavonoid contents (31.3?mg GAE?g(-1) and 16.3?mg RE?g(-1), respectively), followed by L. multifida (30.8?mg GAE?g(-1) and 12.3?mg RE?g(-1)). Methanolic extracts and essential oils displayed significant antioxidant activities. The level of antioxidant capacity varied according to extracts and species.     

Influence of In Vitro Human Digestion Simulation on the Phenolics Contents and Biological Activities of the Aqueous Extracts from Turkish Cistus Species

Oxidative stress is one of the significant precursors of various metabolic diseases such as diabetes, Parkinson’s disease, cardiovascular diseases, cancer, etc. Various scientific reports have indicated that secondary plant metabolites play an important role in preventing oxidative stress and its harmful effects. In this respect, this study was planned to investigate the phenolic profile and antioxidant and antidiabetic potentials of the aqueous extracts from Turkish Cistus species by employing in vitro methods. In vitro digestion simulation procedure was applied to all extracts to estimate the bioavailability of their phenolic contents. Total phenolic, flavonoid, phenolic acid and proanthocyanidin contents were determined for all phases of digestion. In addition, changes in the quantity of the assigned marker flavonoids (tiliroside, hyperoside and quercitrin) were monitored by High-Performance Thin Layer Chromatography (HPTLC) analysis. The antioxidant activity potentials of the extracts were studied by various methods to reveal their detailed activity profiles. On the other hand, in vitro α-amylase and α-glucosidase enzymes and advanced-glycation end product (AGE) inhibitory activities of the extracts were determined to evaluate the antidiabetic potentials of extracts. The results showed that aqueous extracts obtained from the aerial parts of Turkish Cistus species have rich phenolic contents and potential antioxidant and antidiabetic activities; however, their bioactivity profiles and marker flavonoid concentrations might significantly be affected by human digestion. The results exhibited that total phenolic contents, antioxidant activities and diabetes-related enzyme inhibitions of the bioavailable samples were lower than non-digested samples in all extracts.     

Rhamnus pallasii subsp. sintenisii fruit,leaf, bark and root: Phytochemical profiles and biological activities

The genus Rhamnus has received a lot of interest as a source of phenolic chemicals. There have been no reports on the phytochemicals and biological activities of R. pallasii subsp. sintenisii various morphological components (fruit, leaf, bark, and root) in Iran to yet. Two crude ether petroleum (EP) and hydro-methanolic (HM) extracts were obtained from the separate parts. The antioxidant and antibacterial capabilities of the extracts, as well as their phytochemical screening (total phenolic, flavonoid, phenolic acid, and anthocyanin concentrations), were measured. Furthermore, the phytochemical profiles of EP and HM extracts were determined using GC–MS and LC-ESI–MS, respectively. LC-ESI-MS detected 59 chemicals in HM extracts, including flavonoids (62.71 %), phenolic acids (10.16 %), and anthraquinones (16.94 %). Furthermore, the predominant group components in EP extracts examined by GC–MS were fatty acids (58.82%), phenolic compounds (49.28%), and hydrocarbons (35.15 to 59.45 %). In terms of biological testing (DPPH radical scavenging and anti-bacterial activity), all examined extracts, particularly the fruit, had the highest activities in both assays (IC₅₀: 7.52 to 22.39 µg/ml and MIC: 0.39 to 3.12 mg/ml), owing to their high phenolic content. As a result, individual morphological elements of the species might be thought of as natural antioxidant and antibacterial agents.     

Total phenolic content,ferric reducing and DPPH scavenging activity of Arum dioscoridis

Arum dioscoridis, locally called ‘Gavur pancari’, is a wild plant the leaves of which have been used as vegetable and for preparing special soup which has a sour taste. This study was set up to determine in vitro antioxidant activities and total phenolic and flavonoid contents of different extracts of A. dioscoridis. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing activity with different concentrations of ethanol, methanol, acetone and water extracts of the plant leaves. Total phenolic and flavonoid contents were widely variable depending on solvents. Ethanol and methanol extractions of the plant material showed better performances with respect to both phenolic and flavonoid contents, respectively. The highest phenolic and flavonoid contents of ethanol and methanol extracts were 100.890 mg/g GAE and 72.643 mg/g QE, respectively. The lower DPPH scavenging and ferric reducing activities were determined in comparison with previous reports and standard synthetic chemicals.     

Antimicrobial and antioxidant phytochemicals in leaf extracts of Bergenia ligulata: a Himalayan herb of medicinal value

Phenolic and flavonoid contents in leaf extracts of Bergenialigulata have been analysed for their contribution in antimicrobial and antioxidant activities. The extracts were prepared in three solvents (separately) following maceration and soxhelt methods. The antimicrobial activity was tested using disc diffusion assay against a range of microorganisms along with the determination of minimum inhibitory concentration (MIC), while the antioxidant activity was tested following DPPH assay. Leaf extracts exhibited antimicrobial activity against all the three groups of microorganisms; results coincided with respective MIC. In general, the methanol extracts prepared through maceration favoured the determination of antimicrobial and antioxidant activities. Maximum values for phenolic and flavonoid contents were obtained in macerated methanol and ethyl acetate extracts, respectively. The statistical correlations exhibited the extent of the contribution of phenolic and flavonoid contents in antimicrobial and antioxidant activities and also indicated the involvement of other plant metabolites.     

Changes in Organic Acids,Phenolic Compounds,and Antioxidant Activities of Lemon Juice Fermented by Issatchenkia terricola

High content of citric acid in lemon juice leads to poor sensory experience. The study aimed to investigate the dynamics changes in organic acids, phenolic compounds, and antioxidant activities of lemon juice fermented with Issatchenkia terricola WJL-G4. The sensory evaluation of fermented lemon juice was conducted as well. Issatchenkia terricola WJL-G4 exhibited a potent capability of reducing the contents of citric acid (from 51.46 ± 0.11 g/L to 8.09 ± 0.05 g/L within 60 h fermentation) and increasing total phenolic level, flavonoid contents, and antioxidant activities compared to those of unfermented lemon juice. A total of 20 bioactive substances, including 10 phenolic acids and 10 flavonoid compounds, were detected both in fermented and unfermented lemon juice. The lemon juice fermented for 48 h had better sensory characteristics. Our findings demonstrated that lemon juice fermented with Issatchenkia terricola exhibited reduced citric acid contents, increased levels of health-promoting phenolic compounds, and enhanced antioxidant activities.     

Phenolic content and antioxidant properties of soybean (Glycine max (L.) Merr.) seeds

The contents and antioxidant ability of various classes of phenolic compounds present in the seeds of twenty soybean hybrids were evaluated. Total phenolics, tannins and proanthocyanidins were determined spectrophotometrically, after extraction of seeds with 70% aqueous acetone. In addition, the flavonoid contents were determined. The antioxidant activity of aqueous acetone extracts was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay. The highest contents of total phenolics were found in Serbian cultivar 1511 and Chinese cultivar LN92-7369, which also displayed the highest total antioxidant activity. Conversely, genotypes poor in phenolics also showed low levels of DPPH-radical scavenging activity. The results suggested that besides protein and oil contents, the phenolic contents should be also considered as an important characteristic feature of soybean seeds, and as a potential selection criterion for antioxidant activity in soybean.     

Determination of phenolic compounds,in vitro antioxidant activity and characterization of secondary metabolites in different parts of Passiflora cincinnata by HPLC-DAD-MS/MS analysis

Abstract

Ethanol extracts of different parts of Passiflora cincinnata were obtained by maceration. The total phenolic and flavonoid contents were evaluated. The antioxidant activities were determined by β-carotene-linoleic acid bleaching test, 2,2-diphenyl-1-picrylhydrazil (DPPH), and 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging. The crude ethanol stem extract showed the highest amount of total polyphenols (45.53?mg gallic acid equivalent/g) while the highest total flavonoid contents (1.42?mg of quercetin equivalent/g) were observed in the leaf extract. The lowest IC₅₀ (25.65?μg/ml) by the DPPH method was observed for the stem extract. The ABTS method showed a significant antioxidant activity for all investigated extracts. The secondary metabolite composition of ethanol extracts was assessed by HPLC-DAD-MS/MS analysis, leading to the identification of fourteen secondary metabolites in P. cincinnata extracts. These results showed the potentiality of this species as a source of phenolic compounds and antioxidants.     

Antioxidant capacity and phenolic composition of leaves from 10 Bene (Pistacia atlantica subsp. kurdica) genotypes

Leaves of 10 Bene genotypes were collected from six provinces (West Azerbaijan, Kurdistan, Kermanshah, Ilam, Hamedan and Lorestan) in Iran. This study was carried out to better characterise the total phenolic and flavonoid contents, antioxidant capacity and phenolic composition, as well as to evaluate the correlation between content of phenolic compounds and antioxidant activity in 10 genotypes of Bene. The antioxidant activity of leaf extracts was measured using different assays: ferric reducing antioxidant power, nitric oxide radical scavenging and 2,2-diphenyl-1-picrylhydrazyl. The results indicated that the antioxidant capacity can be related to total phenolic and flavonoid content, so that among all the genotypes studied here, the highest and the lowest phenolic content and antioxidant activity were observed in B2 and B10 genotypes, respectively. Analysing the phenolic composition using high performance liquid chromatography, caffeic acid, vanillic acid, ferulic acid and sinapic acid were found in all investigated genotypes.     

Bioactive Compounds from Ephedra fragilis: Extraction Optimization,Chemical Characterization,Antioxidant and AntiGlycation Activities

Response surface methodology (RSM) with a Box–Behnken design (BBD) was used to optimize the extraction of bioactive compounds from Ephedra fragilis. The results suggested that extraction with 61.93% ethanol at 44.43 °C for 15.84 h was the best solution for this combination of variables. The crude ethanol extract (CEE) obtained under optimum extraction conditions was sequentially fractionated with solvents of increasing polarity. The content of total phenolic (TP) and total flavonoid (TF) as well as the antioxidant and antiglycation activities were measured. The phytochemical fingerprint profile of the fraction with the highest activity was characterized by using RP-HPLC. The ethyl acetate fraction (EAF) had the highest TP and TF contents and exhibited the most potent antioxidant and antiglycation activities. The Pearson correlation analysis results showed that TP and TF contents were highly significantly correlated with the antioxidant and antiglycation activities. Totally, six compounds were identified in the EAF of E. fragilis, including four phenolic acids and two flavonoids. Additionally, molecular docking analysis also showed the possible connection between identified bioactive compounds and their mechanisms of action. Our results suggest new evidence on the antioxidant and antiglycation activities of E. fragilis bioactive compounds that may be applied in the treatment and prevention of aging and glycation-associated complications.     

LC-MS/MS Screening,Total Phenolic,Flavonoid and Antioxidant Contents of Crude Extracts from Three Asclepiadaceae Species Growing in Jordan

This study aimed to evaluate the antioxidant activity and total phenolic content (TPC) and total flavonoid content (TFC) of crude extracts obtained from three Asclepiadaceae species, namely, Calotropis procera L., Peruglaria tomentosa L., and Pentatropis spiralis (Forsk.) Decne. Both butanol and aq. methanol extracts of the three species showed the highest amount of phenol and flavonoid contents, which exhibited the greatest antioxidant activity in the scavenging of 2,2-diphenyl-2-picrylhydrazyl free radical (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS), ferrous chelating effect (FIC), and hydroxyl radical (HDR) assays. Phytochemical screening of the extracts revealed the presence of alkaloids, tannins, sponins, flavonoids, terpenoids, and glycosides. LC-MS analysis was carried out to identify the major compounds from each crude extract. A total of 12 phenolic compounds in the extracts of the 3 species were identified and quantified, including 9 flavonoids, 2 hydroxybenzoic acids, and 3 hydroxycinnamic acids. The current study also revealed a good correlation between total phenolic contents and the observed antioxidant activity of the crude extracts.     

Phenolic Compounds and Antioxidant Activity of Bulb Extracts of Six <em>Lilium</em> Species Native to China

Lily (Lilium) is used as an important edible and medical plant species with a vague taxonomic classification and a long history in China. Bulbs of six Lilium species (L. regale, L. concolor, L. pumilum, L. leucanthum, L. davidii var. unicolor and L. lancifolium) native to China were investigated with a view to their exploitation as a potential source of natural antioxidants due to their phenolic composition and dietary antioxidant potential. The results showed that all bulb extracts exhibited strong antioxidant activities, which generally correlated positively with the total phenolic contents (r = 0.68 to 0.94), total flavonoid contents (r = 0.51 to 0.89) and total flavanol contents (r = 0.54 to 0.95). High-performance liquid chromatography (HPLC) analysis revealed that rutin and kaempferol were the major phenolic components in the extracts. Hierarchical cluster analysis showed that L. regale belonged to the group with high phenolic content and strong antioxidant power. L. concolor and L. pumilum were arranged in one group characterized by moderate phenolic content and antioxidant capacity, while L. leucanthum, L. davidii var. unicolor and L. lancifolium were clustered in the third group with low phenolic content and weak antioxidant activity. These strongly suggest that lily bulbs may serve as a potential source of natural antioxidant for food and pharmaceutical applications.     

Antioxidant Potential and Cytotoxic Effect of Isoflavones Extract from Thai Fermented Soybean (Thua-Nao)

Thua-nao, or Thai fermented soybeans, is a traditional Lanna fermented food in Northern Thailand. It is produced by using a specific bacterial species called Bacillus subtilis var. Thua-nao. We investigated the antioxidant activity and cytotoxic effect of isoflavones from Thua-nao. The phenolic compound contents and total flavonoid contents were determined by spectrophotometry. The antioxidant activity was examined using the ABTS, FRAP, and DPPH assays. The isoflavone contents and phenolic compositions were examined by the high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) techniques. The ability of isoflavones to inhibit human cancer cell growth was assessed by the MTT assay. The total phenolic content, total flavonoid content, and antioxidant activities of the isoflavones were 49.00 ± 0.51 mg GAE/g of dry extract (DE), 10.76 ± 0.82 mg QE/g of DE, 61.03 ± 0.97 µmol Trolox/g of DE, 66.54 ± 3.97 µM FeSO₄/g of DE, and 22.47 ± 1.92% of DPPH inhibition, respectively. Additionally, the isoflavone extracts from Thua-nao had high isoflavone contents and polyphenolic compound compositions, especially daidzein and genistein. The isoflavone demonstrated a weak inhibition of MCF-7 and HEK293 cancer cell growth. It has a high antioxidant component, which is beneficial and can be developed for new therapeutic uses. However, further studies on the benefits of Thua-nao should be performed for realizing better and more effective uses soon.     

Phytochemical Composition,Antioxidant Activity, α-Glucosidase and Acetylcholinesterase Inhibitory Activity of Quinoa Extract and Its Fractions

This study is aimed to evaluate the chemical compositions and biological activities of quinoa, a novel and excellent food crop. Quinoa extract and its fractions were prepared by ethanol extraction and liquid-liquid extraction, including ethanol crude extract, and petroleum ether, chloroform, ethyl acetate (EAF), and n-butanol and water fractions. The total phenolic and flavonoid contents, antioxidant activities, α-glucosidase and acetylcholinesterase inhibitory abilities of the extract and fractions were further determined. Based on these foundations, the chemical composition of the EAF fraction exhibiting the strongest functional activity was analyzed by ultra-performance liquid chromatography-mass spectrometry. The results showed the EAF fraction had the highest phenolic and flavonoid contents, and the highest antioxidant activities, as well as the strongest α-glucosidase and acetylcholinesterase inhibitory abilities, which is even better than the positive control. The phytochemical composition of the EAF fraction indicated that 661 and 243 metabolites were identified in positive and negative ion modes, which were classified into superclass, class and subclass levels, respectively. Phenolic acids and flavonoids were the major bioactive compounds in the EAF fraction. This study found that quinoa, especially its ethyl acetate fraction, had the potential for the development of natural antioxidants, acetylcholinesterase inhibitors, and hypoglycemic agents.     

In vitro antioxidant,antifungal and antibacterial activities of five international Calibrachoa cultivars

The total phenolic, flavonoid and tannin contents in leaf extracts of Calibrachoa x hybrida (C.h.) (Solanaceae) international cultivars, as well as their overall antioxidant activities using DPPH and linoleic acid assays, were investigated. Furthermore, the antifungal and the antibacterial activities were examined against a wide spectrum of micro-organisms. DPPH and linoleic acid assays ranged from 62.1 to 80.1% and of 74.1–93.4%, respectively. C.h. Superbells® Trailing Rose (CHST), C.h. Superbells® Frost Fire, C.h. Superbells® Strawberry Punch, C.h. Superbells® Dreamsicle and C.h. Superbells® Plum (CHSP) varied in their antifungal and the antibacterial activities against a wide spectrum of micro-organisms. CHSP exhibited the highest antioxidant, antifungal and antibacterial activities followed by CHST. These activities might be attributed to the presence of phenolic, flavonoid and tannin compounds, indicating that these cultivars might be potential sources of therapeutic substances.     

Antioxidant capacities and total phenolic contents of 56 wild fruits from South China

In order to identify wild fruits possessing high nutraceutical potential, the antioxidant activities of 56 wild fruits from South China were systematically evaluated. The fat-soluble components were extracted with tetrahydrofuran, and the water-soluble ones were extracted with a 50:3.7:46.3 (v/v) methanol-acetic acid-water mixture. The antioxidant capacities of the extracts were evaluated using the ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, and their total phenolic contents were measured by the Folin-Ciocalteu method. Most of these wild fruits were analyzed for the first time for their antioxidant activities. Generally, these fruits had high antioxidant capacities and total phenolic contents. A significant correlation between the FRAP value and the TEAC value suggested that antioxidant components in these wild fruits were capable of reducing oxidants and scavenging free radicals. A high correlation between antioxidant capacity and total phenolic content indicated that phenolic compounds could be the main contributors to the measured antioxidant activity. The results showed that fruits of Eucalyptus robusta, Eurya nitida, Melastoma sanguineum, Melaleuca leucadendron, Lagerstroemia indica, Caryota mitis, Lagerstroemia speciosa and Gordonia axillaris possessed the highest antioxidant capacities and total phenolic contents among those tested, and could be potential rich sources of natural antioxidants and functional foods. The results obtained are very helpful for the full utilization of these wild fruits.     

Impact of Tea Processing on Tryptophan,Melatonin, Phenolic and Flavonoid Contents in Mulberry (Morus alba L.) Leaves: Quantitative Analysis by LC-MS/MS

Mulberry (Morus alba L.) leaves from two cultivars, Yai-Burirum (YB) and Khunphai (KP), were prepared into green tea (GT) and black tea (BT). Compared to fresh leaf (FL) extract, GT and BT extracts were evaluated for their total phenolic and total flavonoid contents. Total phenolic content (TPCs) in all samples ranged between 129.93 and 390.89 mg GAE/g extract. The processing of tea decreased the levels of TPC when compared to FL extracts in both cultivars. The total flavonoid content (TFCs) in all samples was found in the range of 10.15–39.09 mg QE/g extract and TFCs in GT and BT extracts were higher than FL extracts. The change in tryptophan, melatonin, phenolic and flavonoid contents was investigated by liquid chromatography–mass spectroscopy (LC-MS). The results exhibited that tryptophan contents in all samples were detected in the range 29.54–673.72 µg/g extract. Both GT and BT extracts increased tryptophan content compared to FL extracts. BT extracts presented the highest amounts of tryptophan among others in both cultivars. Phenolic compounds were found in mulberry leaf extracts, including gallic acid, caffeic acid, gentisic acid, protocatechuic acid and chlorogenic acid. Chlorogenic acid presented the highest amount in all samples. Almost all phenolic acids were increased in the processed tea extracts except chlorogenic acid. Rutin was the only flavonoid that was detected in all extracts in the range 109.48–1009.75 mg/g extract. The change in phenolic and flavonoid compounds during tea processing resulted in the change in antioxidant capacities of the GT and BT extracts. All extracts presented acetylcholinesterase enzyme (AChE) inhibitory activity with IC₅₀ in the range 146.53–165.24 µg/mL. The processing of tea slightly increased the AChE inhibitory effect of GT and BT extracts. In conclusion, processed tea from mulberry leaves could serve as a new alternative functional food for health-concerned consumers because it could be a promising source of tryptophan, phenolics and flavonoids. Moreover, the tea extracts also had antioxidative and anti-AChE activities.