Metal Chelating Activity Assays Research Articles

Fishing antioxidant 4-hydroxycoumarin derivatives: synthesis, characterization, and in vitro assessments.

Coumarins represent a diverse class of natural compounds whose importance in pharmaceutical and agri-food sectors has motivated multiple novel synthetic derivatives with broad applicability. The phenolic moiety in 4-hydroxycoumarins underscores their potential to modulate the equilibrium between free radicals and antioxidant species within biological systems. The aim of this work was to assess the antioxidant activity of 18 4-hydroxycoumarin coumarin derivatives, six of which are commercially available and the other 12 were synthesized and chemically characterized and described herein. The 4-hydroxycoumarins were prepared by a two steps synthetic strategy with satisfactory yields. Their antioxidant potential was evaluated through three in vitro methods, two free radical-scavenging assays (DPPH• and ABTS•+) and a metal chelating activity assay. Six synthetic coumarins (4a, 4g, 4h, 4i, 4k, 4l) had a scavenging capacity of DPPH• higher than butylated hydroxytoluene (BHT) (IC50=0.58mmol/L) and compound 4a (4-hydroxy-6-methoxy-2H-chromen-2-one) with an IC50=0.05mmol/L outperformed both BHT and ascorbic acid (IC50=0.06mmol/L). Nine hydroxycoumarins had a scavenging capacity against ABTS•+ greater (C3, 4a, 4c) or comparable (C1, C2, C4, C6, 4g, 4l) to Trolox (IC50=34.34µmol/L). Meanwhile, the set had a modest ferrous chelation capacity, but most of them (C2, C5, C6, 4a, 4b, 4h, 4i, 4j, 4k, 4l) reached up to more than 20% chelating ability percentage. Collectively, this research work provides valuable structural insights that may determine the scavenging and metal chelating activity of 4-hydroxycoumarins. Notably, substitutions at the C6 position appeared to enhance scavenging potential, while the introduction of electron-withdrawing groups showed promise in augmenting chelation efficiency.

Process optimization and identification of antioxidant peptides from enzymatic hydrolysate of bovine bone extract, a potential source in cultured meat

Bone protein is a significant secondary product of the meat industry, comprising a substantial quantity of protein. These proteins could be broken down through enzymatic hydrolysis to generate antioxidant peptides. This study aimed to produce antioxidant peptides from bovine bone extract by enzymatic hydrolysis utilizing Flavourzyme and Protamex by optimizing enzyme amounts and time using the Box–Behnken design. The final optimized conditions obtained through the model were as follows: The amount of Flavourzyme was 1,100 U, the amount of Protamex was 2,814 U, and the time was 3.77 (h). Bovine bone extract hydrolysate (BBEH) was purified stepwise using ultrafiltration membranes with molecular cutoffs of 5, 3, and 1 kDa. To assess the antioxidant capacity of the fractions, several methods were used, including radical scavenging activity “1,1-diphenyl-2-picrylhydrazyl (DPPH),” “2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS),” metal chelating activity (MCA), reducing power (RP), and thiobarbituric acid assay (TBA). The results indicated that the ultrafiltration fraction with a molecular weight of less than 1 kDa showed significant antioxidant activity, with 48, 42, and 50% inhibition rates for DPPH, ABTS, and metal chelating, respectively. Using size exclusion chromatography, the fraction with a molecular weight less than 1 kDa was further separated into five sub-fractions: Frac-I, Frac-II, Frac-III, Frac-IV, and Frac-V. Sub-Frac-III, which exhibits significant DPPH radical scavenging activity (55%) and a reducing power of 0.8 at 700 nm, was separated into six sub-sub-fractions using reversed-phase HPLC (RP-HPLC) based on molecular weight and hydrophobicity. The sub-sub-fraction with the highest value for DPPH radical scavenging activity was sub-Fra-III-6, which exhibited approximately 69.45% activity. The sub-Fra-III-6 was analyzed using LC–MS/MS, which identified two specific peptides: Ala-Pro-Phe with a mass of 333.12 Da and Asp-His-Val with a mass of 369.14 Da. These two peptides are likely the primary peptides that might have a crucial role in antioxidant capacity. It can be concluded that BBEH is a valuable source of natural antioxidants and has the potential to serve as a viable resource in the cultured meat industry.

Effects of black seed oil combined with olive oil or honey on antioxidant activities, phenolic content, and identification and quantification of thymoquinone, a key bioactive compound

The plant Nigella sativa (NS) has a rich history in folk medicine, being utilized for various illnesses and as tonic drugs. Furthermore, thymoquinone (TQ), a major compound found in the seeds of NS, may exhibit antioxidant activity. In addition to black candles, traditional medicine employs olive oil and honey to nourish the body. Some folk medicine systems combine NS, honey, and olive oil for improved efficacy; however, knowledge regarding the antioxidant properties of black seed oil (BSO), BSO with olive oil (BSOO), and BSO with honey (BSOH) remains limited. Therefore, in this study, we investigated the antioxidant properties of BSO, BSOO, and BSOH. Gas chromatography-mass spectrometry analysis showed that BSO contained 73.48 ± 1.23 mg/kg TQ. BSO, BSOO, and BSOH exhibited remarkable antioxidant activity, with NO scavenging activities of 94.32, 76.53, and 50.37, respectively. The 2,2-diphenyl-1-picrylhydrazyl and metal chelating activity assays (with half-maximal inhibitory concentration values), oxygen radical antioxidant capacity, and total flavonoid compound content of BSO were 0.135 ± 0.003 mg/mL, 0.005 ± 0.003 mg/mL, 32 ± 0.4 μM Trolox/g extract, and 997 ± 20 mg catechin equivalent/g of extract, respectively. These results are potentially linked to the increased antioxidant activity, as suggested by Pearson's correlation coefficients. In the ferric-reducing antioxidant power assay, the highest antioxidant activity was demonstrated by BSOO and BSOH, with total phenolic content of 7288 ± 300 mM FeSO4/mg and 346 ± 17 mg of gallic acid equivalent/g E, respectively. This study affirms the potent antioxidant properties of BSO, BSOO, and BSOH, emphasizing the importance of further research on NS infusion as a promising antioxidant agent and its application as an anti-aging and tonic drug.

Exploring Apis mellifera L. Venom's Antioxidant Power in Various Solvents: Unveiling its In Vitro Potential

Apis mellifera L. venom contains bioactive components with antioxidant properties. Diluted in various polar solvents, the venom is utilized for therapeutic purposes. This study aims to determine the in vitro antioxidant activities (AOA) of standard crude venom (SV) and venom from breeders (BV) by dissolving them in distilled water, saline, and PBS at concentrations of 1.95-500 µg.ml-1. Radical scavenging activity (DPPH) and metal chelating activity (MCA) assays were employed for AOA assessment. SV dissolved in distilled water exhibited higher RSA (73.26±11.24%) than BV (34.60±21.08%), with no difference between SV, ascorbic acid (AA), and Trolox RSA’s. BV's RSA was lower than AA (75.07±15.59%) and Trolox (84.02±1.63%). BV's MCA (30.31±24.06%) exceeded AA (8.93±16.08%). SV in saline showed higher RSA (63.83±9.73%) than BV (46.99±18.31%), lower than AA (71.63±4.14%) and Trolox (79.01±6.94%). MCAs of SV (85.42±4.65%) and BV (85.53±7.19%) surpassed Trolox (55.06±30.92%). No difference existed between RSA’s of SV (37.16±16.54%) and BV (38.47±17.24%) in PBS, both lower than AA (71.48±3.66%) and Trolox (72.87±6.05%). Optimal RSA and MCA were observed at different solvents and concentrations, indicating the use of 500 µg.ml-1 (1.95 µg.ml-1 BV for RSA) venom dissolved in saline for optimal AOA. PBS or distilled water usage resulted in decreased AOA.

Enzyme inhibitory and antioxidant activities and HPLC quantification of chlorogenic acid in Helichrysum stoechas (L.) Moench and H. stoechas subsp. barrelieri (Ten) Nyman

The inhibitory effects of ethanol (80%) and aqueous extracts of Helichrysum stoechas (L.) Moench and H. stoechas subsp. barrelieri (Ten) Nyman on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), two sister enzymes associated with pathogenesis of Alzheimer's disease (AD), as well as on elastase and collagenase, linked to inflammation and skin aging, were investigated. Simultaneously, antioxidant activity of the extracts was assessed through DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), and metal-chelating activity assays, since oxidative damage plays a critical role in both AD pathophysiology and skin aging. Total phenol and flavonoid contents in the extracts were spectrophotometrically determined. The highest AChE inhibitory activity (44.60 ± 4.4% at 2000 µg/mL) was found in the ethanol extract of H. stoechas subsp. barrelieri collected from Hatay, and the uppermost BChE inhibitory activity at same concentration was found in the aqueous extract of H. stoechas subsp. barrelieri collected from Izmir (80.24 ± 2.63%, IC50: 38.52 ± 1.41 µg/mL). Both of them inhibited AChE and BChE in a concentration-dependent manner. Nevertheless, none of the extracts from the two plants inhibited the elastase and collagenase. Although both ethanolic and aqueous extracts had significant antioxidant activity in DPPH radical scavenging and FRAP assays, they demonstrated inadequate antioxidant activity in metal-chelating assay. Chlorogenic acid was quantified in the extracts using HPLC. The mentioned two extracts having strong cholinesterase (ChE) inhibition had also the highest chlorogenic acid content. The ethanol extract of H. stoechas (Hatay sample) and the aqueous extract of H. stoechas (Izmir sample) seem to contain promising ChE inhibitors, which deserve further investigation.

Towards a better understanding of commonly used medicinal plants from Turkiye: Detailed phytochemical screening and biological activity studies of two Teucrium L. species with in vitro and in silico approach

Ethnopharmacological relevanceSince ancient times, Teucrium L. species have been among the most commonly used traditional medicinal plants mainly in the Mediterranean region. From tackling gastrointestinal problems to maintaining the healthy functioning of endocrine glands, and from treating malaria to severe dermatological disorders, Teucrium species are known to have extensive therapeutic applications. Teucrium polium L. and Teucrium parviflorum Schreb. are the two members of the genus that have been used in Turkish folk medicine for various medicinal purposes. Aim of the studyTo determine the phytochemical compositions of the essential oils and ethanol extracts of Teucrium polium and Teucrium parviflorum collected from different locations in Turkiye along with the investigation of in vitro antioxidant, anticancer, antimicrobial activities, and both in vitro and in silico enzyme inhibitory activities of the extracts. Materials and methodsEthanol extracts of Teucrium polium aerial parts and roots, and aerial parts of Teucrium parviflorum were prepared. Volatile profiling of the essential oils by GC-MS, phytochemical profiling of the ethanol extracts by LC-HRMS, antioxidant activity by DPPH radical scavenging, ABTS cation radical scavenging, CUPRAC, and metal chelating activity assays, anticholinesterase, antityrosinase, antiurease, activities by different enzyme inhibitory activity assays, anticancer activity by SRB cell viability assay, and antimicrobial activity against a standard panel of bacteria and fungi by the microbroth dilution technique. Molecular docking studies were performed by Autodock Vina (Ver. 1.1.2). ResultsThe studied extracts were found to be quite rich in various biologically important volatile and phenolic compounds. (−)-Epigallocatechin gallate, which is a molecule renowned for having great therapeutic potential, was the major compound of all extracts. Teucrium polium aerial parts extract was revealed as a great source for naringenin with 16327 ± 685.23 μg/g extract. All extracts exerted significant antioxidant activity by different methods. All extracts demonstrated antibutrylcholinesterase, antityrosinase, and antiurease activities by in vitro and in silico assays. Teucrium polium roots extract stood out with remarkable tyrosinase and urease inhibitory and cytotoxic activities. ConclusionThe obtained results from this multi-disciplinary study proves that the traditional use of these two Teucrium species is justified, and the mechanisms behind are enlightened.

Screening of Phytochemical Profile and Biological Activities in the Leaves, Stems and Roots of South African Portulacaria Afra using Four Extraction Solvents

Portulacaria afra, is indigenous to South Africa and has been identified to have several medicinal properties according to traditional knowledge and few studies. The drive around this research is to evaluate the medicinal properties of the leaves, stems and for the first time the roots extracts of Portulacaria afra, using four solvents with different polarities. The aqueous (60°C), methanol, n-hexane and ethyl acetate whole plant extracts of P. afra were investigated for their phytochemical properties, antimicrobial and antioxidant activity. The phytochemical screening revealed that the methanolic and aqueous extracts of the leaves displayed high presence of secondary metabolites compared to n-hexane and ethyl acetate extracts. The methanolic leaves extracts showed strong presence of quinones, phenols, steroid and coumarins while the aqueous leaves extracts contained a moderate presence of saponins, terpenoids, quinones and coumarins. Ethyl acetate leaves extracts revealed a strong presence of tannins, moderate presence of phytosteroids and a low presence of volatile oil. Meanwhile, the leaves extracts with n-hexane showed a considerable amount of saponins with a moderate presence, and a low presence of tannins, volatile oils and terpenoids. The methanolic stems extracts displayed the most significant presence of secondary metabolites, showing a high presence of terpenoids, steroids, phenols and coumarins. The aqueous stems extracts showed a strong presence of glycosides with a moderate presence of saponins. However, ethyl acetate and n-hexane stems extracts displayed a few secondary metabolites with their concentration ranging from medium to low. The ethyl acetate roots extracts displayed a significant elevated amount of quinones with a strong presence. n-hexane roots extracts showed a moderate presence of volatile oil and a low presence of tannins and steroids. Methanolic roots extracts showed a moderate presence of coumarins and glycosides while aqueous roots extracts showed a low presence of glycosides. The overall highest total phenolics contents (TPCs) and total flavonoids contents (TFCs) in all the plant parts, were found to be in the methanol stems extracts and aqueous roots extracts respectively. Next to the methanol leaves and aqueous leaves extracts respectively. However, in the root’s extracts, the aqueous extracts showed the highest total phenolics content while the water extracts had the highest total flavonoids contents. The antimicrobial activities of P. afra whole plant extracts with the various four solvents were tested against three microorganisms Escherichia coli, Staphylococcus aureus and Streptomyces griseus using agar-well diffusion method. The Antimicrobial activity of the n-hexane extracts of the leaves, stems and roots of P. afra presented a wide range of inhibition against all the test microorganisms, ethyl acetate leaves extract showed a considerable effect against Staphylococcus aureus while the methanolic extracts were not active. Aqueous roots extracts demonstrated a strong antimicrobial activity against Staphylococcus aureus while the other extracts were not active. The zones of inhibition ranged from 13 to 24 mm for the plant extracts. The antioxidant activity potential of the aqueous, methanol, n-hexane and ethyl acetate extracts of P. afra leaves, stems and roots extracts were observed through a 2, 2 diphenylpicryhydrazyl (DPPH) free radical assay, hydrogen peroxide scavenging (H₂O₂) and metal chelating activity assay. Ethyl acetate roots extracts exhibited the strongest hydrogen peroxide scavenging activity compared to the other extracts. Meanwhile, aqueous stems extracts showed the highest antioxidant activity against DPPH radical. Aqueous and n-hexane roots extracts displayed the strongest metal chelating ability. These findings reveal the efficacy of the use of several solvents with different polarities for effective and more accurate extraction of various compounds and indicate that the antimicrobial and antioxidant activity of P. afra parts are dependent on the solvent extracts.

Free Radical Scavenging, Metal chelating and Antiperoxidative Activities of M. communis Berries Methanol extract and its Fractions

Oxidative stress resulted from free radicals and reactive oxygen species (ROS) are associated with many diseases. Phytotherapy has known a great evolution all the world and some medicinal plants are important remedies of some diseases. Myrtle (Mrytus communis L.) is a plant of Myrtaceae family which is common in the Mediterranean region, with flowering, always green leaves and fruit. This study aims to investigate in vitro antioxidant capacity of Myrtus communis berries methanol extract and its three fractions using five assays: ABTS scavenging radicals, metal chelating, hydrogen peroxide and inhibition of lipid peroxidation assays. EAE extract possessed the highest antioxidant activity in ABTS (EAE (IC50=2.5 µg/ml ) and lipid peroxidation models (90.17%). Whereas, AqE is the most active extract in metal chelating activity (IC50=0.73±0.03 mg/ml) and H2O2 assay. These results support the traditional use of this plant in healthcare and it could be a new source of antioxidant natural drugs.

Protective potential of sulfated polysaccharides from tropical seaweeds against alkylating- and oxidizing-induced genotoxicity

Sulfated polysaccharides (SPs) from seaweeds are potential bioactive natural compounds, but their DNA protective activity is poorly explored. This article aimed to evaluate the genotoxic/antigenotoxic potentials of a sulfated heterofucan from brown seaweed Spatoglossum schröederi (Fucan A – FA) and a sulfated galactan from green seaweed Codium isthomocladum (3G4S) using in vitro Comet assay (alkaline and oxidative versions) with HepG2 cells. The antioxidant activity of these SPs was evaluated by total antioxidant capacity, radical scavenging, metal chelating, and antioxidant enzyme activity assays. Both SPs were not genotoxic. FA and 3G4S displayed strong antigenotoxic activity against oxidizing chemical (H2O2) but not against alkylating chemical (MMS). The DNA damage reduction after a pre-treatment of 72 h with these SPs was 81.42% to FA and 81.38% to 3G4S. In simultaneous exposure to FA or 3G4S with H2O2, HepG2 cells presented 48.04% and 55.41% of DNA damage reduction compared with the control, respectively. The antigenotoxicity of these SPs relates to direct antioxidant activity by blockage of the initiation step of the oxidative chain reaction. Therefore, we conclude that FA and 3G4S could be explored as functional natural compounds with antigenotoxic activity due to their great protection against oxidative DNA damage.

Investigation on the Phytochemical Composition, Antioxidant and Enzyme Inhibition Potential of Polygonum Plebeium R.Br: A Comprehensive Approach to Disclose New Nutraceutical and Functional Food Ingredients.

The present work describes medicinal potential and secondary metabolic picture of the methanol extract (PP-M) of Polygonum plebeium R.Br. and its fractions; hexane (PP-H), ethyl acetate (PP-E) and water (PP-W). In total bioactive component estimation, highest contents of phenolic (89.38±0.27 mgGAE/g extract) and flavonoid (51.21±0.43 mgQE/g extract) were observed in PP-E, and the same fraction exhibited the highest antioxidant potential in DPPH (324.80±4.09 mgTE/g extract), ABTS (563.18±11.39 mgTE/g extract), CUPRAC (411.33±15.49 mgTE/g extract) and FRAC (369.54±1.70 mgTE/g extract) assays. In Phosphomolybdenum activity assay, PP-H and PP-E showed nearly similar potential, however, PP-H was the most active (13.54±0.24 mgEDTAE/g extract) in metal chelating activity assay. PP-W was the stronger inhibitor (4.03±0.05 mgGALAE/g extract) of the enzyme AChE, while PP-H was potent inhibitor of BChE (5.62±0.27 mg GALAE/g extract). Interestingly, PP-E was inactive against BChE. Against tyrosinase activity, PP-E was again the most active fraction with inhibitory value of 71.89±1.44 mg KAE/g extract, followed by the activity of PP-M and PP-W. Antidiabetic potential was almost equally distributed among PP-M, PP-H and PP-E. For mapping the chemodiversity of P. plebeium, PP-M was analyzed through UHPLC/MS, which led to the identification of more than 50 compounds. Flavonoids were the main components derived from isovitexin, kaempferol and luteolin however, gallic acid, protocatechuic acid, gingerols and lyoniresinol 9'-sulfate were among important bioactive phenols. These findings prompted to conclude that Polygonum plebeium can be a significant source to offer new ingredient for nutraceuticals and functional foods.

Antimicrobial, Antioxidant and Antihemolytic Activities of Two Daphne gnidium Leaves Extracts

In this study, Daphne gnidium leaves extracts were screened for their Phenolic content, antimicrobial, antioxidant and antihemolitic activities. Decoction and maceration were used to obtain the aqueous (Aq E) and the ethanolic extract (Et E), respectively. Total phenolic content was determined using Folin–Ciocalteu reagent. Moreover, a disc diffusion assay and inhibition of mycelial growth test were applied to evaluate the antibacterial and antifungal activity. The extracts were also tested for their antioxidant effects in terms of DPPH, OH, H2O2, β-carotene, and ferrous ion chelating assays. To investigate antihemolytic activity, the 2,2,-azobis (2-amidinopropane) dihydrochloride (AAPH) was used to induce erythrocyte oxidative hemolysis. Results indicated that ethanolic extract (Et E) contains the highest polyphenol content (775.25 μg GAE/mg extract). The Et E inhibited the growth of bacterial strains with inhibition zone diameters from 7 to 15 mm. In contrast, no activities have been found against all fungal strains. In antihemolytic test, aqueous and ethanolic extracts showed almost the same effect with an HT50 value of 106 min. Ethanolic extract was found to be more active in DPPH and β-carotene assays (IC50: 5.76 μg/ml and 70% inhibition respectively). However, the aqueous extract showed a greater effect than the ethanolic one in metal chelating activity assay (IC50: 170 μg/ml), OH scavenging effect assay (IC50: 9.67 μg/ml) and H2O2 scavenging assay (IC50: 133.2 μg/ml).

Comprehensive Biological and Chemical Evaluation of Two Seseli Species (S. gummiferum and S. transcaucasicum).

Seseli L. is one of the largest genera of the Apiaceae family widely known for their traditional uses as herbal remedies. In the present study, the methanolic and water extracts of two Seseli species, S. gummiferum and S. transcaucasicum were evaluated for their bioactive contents and biological activities. The total phenolic and flavonoid contents in the extracts ranged from 19.09 to 24.33 mg GAE/g and from 0.45 to10.09 mg RE/g, respectively. Moreover, while narcissin was detected as the most abundant component in the methanolic extract of S. transcaucasicum (261.40 µg/g), chlorogenic acid was identified as the major component in all the other extracts, although a high amount was also present in the methanolic S. transcaucasicum extract (107.48–243.12 µg/g). The total antioxidant capacity was also determined by the phosphomolybdenum assay (0.66–1.18 mM TE/g). Other antioxidant assays such as the radical scavenging assays (DPPH: 5.51–11.45 mg TE/g; ABTS: 43.46–51.91 mg TE/g), reducing assays (CUPRAC: 41.67–53.20 mg TE/g; FRAP: 31.26–34.14 mg TE/g), as well as the metal chelating activity assay (14.38–38.57 mg EDTAE/g) were conducted. All the extracts showed inhibitory potential against the enzyme’s amylase (0.12–0.78 mM ACAE/g), acetyl- and butyryl-cholinesterase (0.15–9.71 mg GALAE/g), while only the methanolic extracts acted as inhibitors of tyrosinase (107.15 and 109.37 mg KAE/g) and only the water extract of S. gummiferum displayed anti-glucosidase activity (0.13 mM ACAE/g). Interestingly, the methanolic extracts of both Seseli species showed lower cytotoxicity towards HaCaT cells (IC50: >500 µg/mL), compared to the water extracts (IC50: 267.8 and 321.41 µg/mL). Besides, only the methanolic extracts showed a slight wound healing effect (28.21 and 31.23%). All extracts showed antibacterial action against Staphylococcus lugdunensis (minimum inhibitory and bactericidal concentrations: 0.025–2 mg/mL). S. gummiferum methanolic extract, which exhibited the highest antibacterial potency was found to inhibit adhesion and invasion of S. lugdunensis to HaCaT cells as well. Taken together, this study demonstrated the two Seseli species to harbour interesting bioactive components, in particular polyphenolics and to exhibit several biological properties that could be further investigated for their potential exploitation as healing agents as supported by various traditional medicinal uses.

Phytochemical screening, antioxidant, anti-diabetic and cytotoxic activity of leaves of Pandanus canaranus Warb

Pandanus, a traditional medicinal plant is used for the ailment of several diseases in India. The extract prepared from leaves was tested for its secondary metabolites and also to phenolics, alkaloids, saponins and flavonoids. Subsequently, the antioxidant activity was observed using DPPH, reducing power, FRAP, metal chelating activity and total antioxidant assays. It is evident that more secondary metabolites were present in ethyl acetate and methanol solvents enriched in free radicals scavenging ability compared with other solvents. Further, the extracts were tested and observed for potential presence of anti-diabetic activity with strong inhibition of α-amylase and α-glucosidase which suggests that the absorption and digestion of carbohydrates would possibly reduce the blood glucose levels and hence help management of type-2 diabetes. Though the ethyl acetate and methanol extract exhibited cytotoxicity and apoptosis activity on human HT-29 colon cancer cell line via MTT, AO/EtBr and DAPI staining assays that inhibits cancer cell line which in turn prevents cancer.

In vitro antioxidant, anticholinesterases, anti-α-amylase, and anti-α-glucosidase effects of Algerian Salvia aegyptiaca and Salvia verbenaca.

In this study, Salvia aegyptiaca and Salvia verbenaca aerial part decoction and methanol extracts (SAE DE, SAE ME, SVR DE, and SVR ME) were screened for their in vitro antioxidant, anti-Alzheimer, and antidiabetic enzymes inhibition activities. The antioxidant properties of Salvia extracts were determined using DPPH radical scavenging, ABTS radical scavenging, Alkaline DMSO superoxide radical scavenging, β-carotene bleaching, reducing power, and metal chelating activity assays. All extracts showed high antioxidant capacity and the antioxidant properties with the best performance were detected in the SAE ME and SVR ME. The extracts of S. aegyptiaca and S. verbenaca showed a low inhibitory activity of acetylcholinesterase (AChE), whereas, the methanol extract of S. aegyptiaca had the highest inhibitory activity on butyrylcholinesterase (BChE) (71.60±4.33% for 100µg/ml) compared to the other extracts. In vitro inhibitory effect on diabetic enzymes showed that the ME inhibited α-amylase enzyme with an IC50 86 and 101µg/ml for SAE and SVR, respectively. Similarly, both extracts inhibited α-glucosidase with (IC50 97 and 150µg/ml, respectively). The decoction extracts exhibited lower activity on both enzymes. PRACTICAL APPLICATIONS: It is becoming evident that oxidative stress is involved in several acute and chronic diseases. Counteracting free radical generation has become one of the widest fields of research worldwide. This study deals with the in vitro antioxidant activity of two plants from the Salvia genus as well as the assessment of their in vitro inhibitory properties of four key enzymes implicated in diabetes and Alzheimer's disease. Concerning the practical applications of our work, it can be explored in its antioxidant part as a food supplement to prevent the excess of free radicals in the body and also in other industrial practices. Another potential use is in the prevention and amelioration of both diabetes and Alzheimer's disease symptoms for the extracts that had enzyme inhibitory activity, but this deserves further toxicological and in vivo studies.

Evaluation of Phytochemical Compositions and Biological Properties of Achillea gypsicola at Different Phenological Stages.

Phytochemicals, which are commonly found at different levels in many medicinal plants, are natural strong antioxidants used in traditional medicine. In this research, determination of differences of phytochemical compositions and biological properties were aimed as periodically (pre-, full and post flowering) and daily (6 am, 1 pm and 8 pm) in Achillea gypsicola Hub.-Mor. The volatile oils belonging to A. gypsicola were obtained by hydrodistillation and analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC/MS). The antimicrobial activities of the volatile oils were determined with disc diffusion method. The microdilution method was used to determine minimum inhibitory concentration (MIC). Total phenolic and flavonoid contents were determined by spectrophotometric methods and antioxidant capacities were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, reducing power (RP) and metal chelating activity (MCA) assay. In addition, the phenolic acid and flavonoid compositions were evaluated by reversed phase-high-performance liquid chromatography (RP-HPLC). This study presented a comprehensive report for the first time on evaluation of the phytochemical composition and the biological properties of A. gypsicola at different phenological stages. Thirty-two compounds, containing the major component as camphor, 1,8-cineole and borneol, were detected. Designated harvest time for the highest yield of volatile oils was found to be at full flowering stage-1 pm. It has been observed that the volatile oil composition changes periodically and even daily. Also, in this research, menthol and menthone were found as the composition of volatile oil in Achillea species for the first time. Full flowering stage was found as the richest period in terms of phenolic acid and flavonoid compositions of A. gypsicola for the first time. The species examined in this research showed a high antioxidant and antimicrobial activity in comparison to other studies with Achillea species. The volatile oils exhibited high performances with range of inhibition zones (8.3-42.3 mm) and minimum inhibitory concentration values (2.25-144 μg/ml). Besides, a high correlation between antioxidant activity and phenolic content of A. gypsicola was found. These results suggest that A. gypsicola can be used as a safe source in the cosmetic, food and pharmaceutical industries.

Chemical Profile and Antioxidant Activity of Zinnia elegans Jacq. Fractions.

Zinnia elegans (syn. Zinnia violacea) is a common ornamental plant of the Asteraceae family, widely cultivated for the impressive range of flower colors and persistent bloom. Given its uncomplicated cultivation and high adaptability to harsh landscape conditions, we investigated the potential use of Z. elegans as a source of valuable secondary metabolites. Preliminary classification of compounds found in a methanolic extract obtained from inflorescences of Z. elegans cv. Caroussel was accomplished using HR LC-MS techniques. The extract was then subjected to solid-phase extraction and separation using Sephadex LH-20 column chromatography, which resulted in several fractions further investigated for their antioxidant properties through lipoxygenase inhibition and metal chelating activity assays. Moreover, following additional purification procedures, structures of some active ingredients were established by NMR spectroscopy. The investigated fractions contained polyphenolic compounds such as chlorogenic acids and apigenin, kaempferol, and quercetin glycosides. Antioxidant assays showed that certain fractions exhibit moderate 15-LOX inhibition (Fr 2, IC50 = 18.98 μg/mL) and metal chelation (e.g., Fr 1-2, EC50 = 0.714–1.037 mg/mL) activities as compared to positive controls (20.25 μg/mL for kaempferol and 0.068 mg/mL for EDTA, respectively). For Fr 2, the 15-LOX inhibition activity seems to be related to the abundance of kaempferol glycosides. The NMR analyses revealed the presence of a kaempferol 3-O-glycoside, and a guanidine alkaloid previously not described in this species.

Comparative studies on the antioxidant potential of hydrolysates of <i>Mormyrus rume</i> muscle protein

This study determined the degree of hydrolysis of Mormyrus rume muscle proteins by digestive proteases and the antioxidant potential of the hydrolysates produced was evaluated. The proteins were extracted with distilled water adjusted to neutral pH. The proteases used include trypsin, chymotrypsin and pepsin and the degree of hydrolysis was determined using trichloroacetic acid precipitation method. The antioxidative activities of the hydrolysates were evaluated using different in-vitro antioxidant assay methods such as 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging, hydrogen peroxide scavenging, metal chelating capacity and reductive potentials. Degree of hydrolysis was generally low and ranges between 17.68% and 32.20% with pepsin given the highest degree of hydrolysis. The protein hydrolysates obtained with trypsin exhibited the highest antioxidant activities when assessed with metal chelating activity assay with half maximal inhibitory concentration (IC ) of 0.32 ± 0.01 mg/ml; hydrogen peroxide scavenging assay with IC of 0.18 ± 0.01 mg/ml 50 50 and reductive potential of 0.41 ± 0.002 units at the highest concentration tested (1.0 mg/ml). Pepsin-produced hydrolysates showed the highest DPPH radical scavenging potential at all concentrations with IC of 0.35 ± 50 0.003mg/ml. The study concluded that the hydrolysates produced contain bioactive peptides which possessed significant amount of antioxidant activities, which may be a promising health promoting agent if isolated. Keywords : Hydrolysates, Pepsin, Trypsin, Chymotrypsin, Antioxidant, Enzyme, Mormyrus rume .

Chemical Profile, In Vitro Enzyme Inhibitory, and Antioxidant Properties of Stereum Species (Agaricomycetes) from Turkey.

Recently, mushroom species have been the focus of researchers' interest because of several bioactivities. The aim of this study was to investigate the chemical profile and biological activities of various extracts of two Stereum species (S. rugosum and S. sanguinolentum). Antioxidant activity was tested using β-carotene-linoleic acid, DPPH scavenging, ABTS·+ scavenging, cupric-reducing antioxidant capacity (CUPRAC), and metal chelating assays. The extracts were also tested for their enzyme inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). HPLC-DAD was applied for the analysis of phenolic compounds, and fatty acid compositions were determined using GC and GC-MS. When fumaric acid and catechin hydrate were found as the most abundant phenolic compounds in both Stereum species, oleic acid and palmitic acid were identified as major fatty acids. Both of the studied Stereum methanol extracts were determined as the most active in β-carotene-linoleic acid, DPPR, ABTS·+, and CUPRAC assays; the n-hexane extracts were found to be most active in metal chelating and AChE inhibitory activity assays. In addition, the methanol extract of S. sanguinolentum (IC50: 34.26 ± 0.31 μg/mL) showed higher ABTS·+ scavenging activity than α-tocopherol (IC50: 38.51 ± 0.54 μg/mL). The acetone extracts were found as potent inhibitors against BChE. These results suggest that Stereum species could be an antioxidant source and cholinesterase agent in pharmaceutic, food, and cosmetics industries.

Antioxidant peptides (

The effect of the addition of rennet from different origin (animal, plant and microbial) on the release of potential antioxidant peptides was evaluated in hard cow milk cheese. After cheese making, chemical parameters, colour, TBARs and riboflavin content were determined in the final product. Antioxidant activity of the water soluble extracts from cheese was evaluated by the DPPH radical scavenging and metal chelating activity assays. Separation of peptide fractions (<3 kDa) was performed by RP-HPLC and fractions with potential antioxidant activity were analyzed by LC-MS/MS for further identification of peptides. Results suggested that colour and riboflavin content were affected by the type of rennet used (P < .05). On the other hand, extracts of cheese with microbial rennet showed the highest antioxidant activity (P < .05). Only nine fractions isolated from the extracts showed either DPPH radical scavenging or metal chelating activities. Peptides EIVPN and DKIHPF, previously reported in other studies by showing ACE-inhibitory activity, were identified in these fractions and revealed high metal chelating activity. Moreover, a new peptide, with also high metal chelating activity, has been identified (VAPFPQ). In conclusion, it would be worthwhile to synthesis these peptides and confirm their antioxidant and metal chelating activities.

Phenolic profile and biological properties of the leaves of Ficus vasta Forssk. (Moraceae) growing in Egypt

BackgroundFicus vasta Forssk. (Moraceae) is traditionally used for the treatment of various ailments; nonetheless, this species has been poorly studied to date. This work aimed to characterize the phenolic profile and to evaluate the antioxidant and antimicrobial properties of a hydroalcoholic extract obtained from F. vasta leaves collected in Egypt.MethodsThe phenolic profile of the extract was characterized by HPLC-PDA/ESI-MS. The antioxidant properties were examined by different in vitro systems: DPPH test, reducing power and metal chelating activity assays. Moreover, the ability of the extract to protect Escherichia coli growth and survival from H2O2-induced oxidative stress was evaluated. The potential toxicity was investigated using Artemia salina lethality bioassay. Finally, the antimicrobial properties against a representative set of Gram-positive and Gram-negative bacterial strains and the yeast C. albicans were assayed by standard methods.ResultsBy HPLC-PDA/ESI-MS analysis 12 compounds belonging to the groups of phenolic acids and flavonoids were identified. The extract exhibited strong radical scavenging activity in DPPH test (IC50 = 0.0672 ± 0.0038 mg/mL), reducing power (3.65 ± 0.48 ASE/mL) and chelating activity (IC50 = 0.801 ± 0.007 mg/mL). A total protection against H2O2-induced damage on E. coli was observed. No toxicity against A. salina was found (LC50 > 1000 μg/mL). The extract exhibited bacteriostatic activity against almost all the bacteria tested (MICs: 250–62.5 μg/mL).ConclusionsThe obtained results demonstrate the potential of F. vasta leaves as safe sources of natural antioxidant and antimicrobial compounds.