Radical Cation Scavenging Research Articles

A Comparative Study of the Biological Properties of Eugenia uniflora L. Fruits and Leaves Related to the Prevention of Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain the leading cause of death globally, emphasizing the need for effective preventive strategies. Plant-based foods, rich in phytochemicals, offer a promising potential in CVD prevention. This study investigated the antioxidant, anti-inflammatory, and antihypertensive properties of two Eugenia uniflora L. varieties (orange and purple pitanga) and their leaves. Their antioxidant activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity assays, while their antihypertensive activity was evaluated through angiotensin-converting enzyme (ACE) inhibition. Their anti-inflammatory potential was determined via protein denaturation inhibition. Both fruit varieties exhibited similar bioactivities, with the purple variety showing a slightly higher activity, except in the DPPH and ABTS assays. The leaves consistently demonstrated the lowest activities across all assays. Free polyphenols, dominated by gallic acid, were quantified using µ-QuEChERS followed by ultrahigh-performance liquid chromatography (UHPLC-PDA). The orange variety contained the highest concentration of gallic acid (13.1 mg/100 g DW). These findings highlight the potential of Eugenia uniflora L. extracts as natural antioxidant, anti-inflammatory, and antihypertensive agents, suggesting their value in food, pharmaceutical, and cosmetic applications for promoting human health and preventing CVDs.

Analysis of Polyphenolic Composition, Antioxidant Power and Stress-Response Effects of Fractionated Perilla Leaf Extract on Cells In Vitro

Background/Objectives: Perilla frutescens has historically been used to protect against inflammation and redox stress. This has been partly attributed to its high polyphenolic content; however, polyphenolic components in Perilla extract remain incompletely defined. This study aimed to characterise the polyphenolic composition in Perilla extract and evaluate its effect on the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), regulating antioxidant defenses during inflammation and oxidative stress. Methods: Hot water extraction from Perilla leaves was followed by fractionation using four solvents of different polarity, namely methanol, butanol, ethyl acetate and ether. The polyphenolic composition of these fractions was analysed using RP-HPLC, and some of these compounds were quantified. The total phenolic, flavonoid, and ortho-diphenolic contents of each Perilla fraction were determined. The antioxidant activity was assessed using metal cation reduction and radical scavenging assays. A dual-luciferase assay using a human NQO1 ARE-luciferase reporter plasmid was employed to quantify Nrf2 activation by the Perilla fractions. Results: HPLC analysis identified 35 polyphenolic compounds, with the highest phenolic content present in the polar fractions and rosmarinic acid being the major constituent. Radical scavenging tests (DPPH and ABTS) confirmed the highest antioxidant capacity in the polar fractions. On cells in vitro, the methanol Perilla fraction displayed the strongest antioxidant activity, showing up to a 1.5-fold increase in human NQO1 ARE-luciferase reporter induction. Conclusions: This study has shown that Perilla extract contains a diversity of polyphenolic compounds contributing to its potent antioxidant effects, with methanol and butanol being the most efficient extraction solvents. While rosmarinic acid is expected to be the major contributor towards providing protection against inflammation and redox stress, further work is required on the synergystic effects between different polyphenols.

Fungal Submerged Fermentation of Coffee Silverskin: A Sustainable Source of Natural Meat Additives

The coffee industry, while processing coffee beans, generates residues like husk, pulp, and silverskin, which have been considered a promising source of bioactive metabolites. Recovering these metabolites offers a sustainable strategy to obtain natural food additives. Based on the above, this study aimed to determine the effect of the aqueous extract obtained from maceration and fungal fermented coffee silverskin (CSS) on ground pork meat’s oxidative and microbiological stability. Treatments used to recover bioactive compounds from CSS were the following: maceration extraction (ME) using 0, 1.5, and 3.0% of CSS (ME–0%, ME–1.5%, and ME–3%); fungal submerged fermentation extraction (FE) using 0, 1.5, and 3.0% of CSS (FE–0%, FE–1.5%, and FE–3%) and Pleurotus pulmonarius mycelium. Concerning metabolite content and bioactivity, results showed a decrease in the carbohydrate content of the ME and FE-obtained, as well as an increase in the phenol, flavonoid, and caffeoylquinic acid content. Also, an increase in radical cation scavenging activity, reducing power values and antibacterial activity of the extracts obtained with FE, was observed. Regarding pork meat homogenate treated with ME and FE extracts and subjected to oxidation with potassium ferrocyanide, results demonstrated that inclusion of FE-obtained extract led to decreased pH, lipid oxidation, metmyoglobin, and color changes (L*, a*, b*, C*, and h*), and microbial growth. These results demonstrate that CSS aqueous extract obtained with FE can be considered a potential additive for the meat industry with antioxidant and antibacterial activity. Nevertheless, further research is necessary to assess the sensory impact, biochemical mechanism, food safety, sustainability, and industrial feasibility of these extracts for broader applications.

Investigating the Pharmacological Potential of Micromeria myrtifolia Boiss. & Hohen.: Phenolic Profiling and Biological Activity Assessments

Micromeria myrtifolia Boiss. & Hohen. is a valuable medicinal plant in Türkiye, recognized for its extensive applications across the country. In this study, plant samples were collected from Muğla, Türkiye and extracts from both the aerial parts and roots were prepared using ethanol. To elucidate their phytochemical composition, a comprehensive LC-MS/MS analysis was conducted. The results revealed that both extracts were quite rich in phenolic compounds. Notably, nicotiflorin was the major constituent in both extracts (12878.31355.44 μg/g extract in the aerial parts and 47512.41311.34 μg/g extract in the roots) along with significant phenolic acids such as rosmarinic acid and caffeic acid as well as flavonoids like hesperidin. Moreover, both extracts demonstrated substantial antioxidant activities compared to the synthetic antioxidant compounds as evaluated by DPPH free radical scavenging, ABTS cation radical scavenging, and CUPRAC activity assays. Both aerial parts and root extracts also exhibited meaningful anti-glucosidase activity with 73.030.16% and 47.060.41%, respectively, at 2 mg/mL concentration. The root extract also showed moderate butyrylcholinesterase inhibitory activity. This study contributes to the existing body of knowledge with valuable insights regarding the phytochemical profile and biological activities of M. myrtifolia, paving the way for future research aimed at exploring its medicinal properties and potential uses in traditional and modern medicine.

Antioxidant and neuroprotective potential of extracts from Hass avocado peel obtained through a biorefinery process: A sustainable strategy for the valorization of agro-food waste

This study presents a novel three-step biorefinery approach for extracting bioactive compounds from Hass avocado (Persea americana, Mill.) epicarp. By sequentially using supercritical CO2, CO2-expanded ethanol, and subcritical water, we efficiently recovered a diverse range of extracts with distinct phytochemical profiles and potent biological activities. Our innovative extraction strategy outperformed conventional methods, demonstrating the potential of biorefinery for sustainable valorization of agricultural byproducts. Medium and high extracts exhibited strong antioxidant and anticholinesterase activity. For example, the CO2-expanded ethanol extracts demonstrated an ABTS radical cation scavenging capacity of 3.01 ± 0.06 mmol Trolox equivalents/g and an SC50 value of 53.4 ± 1.2 μg/mL for anticholinesterase activity. These findings highlight the feasibility of integrating biorefinery processes into circular economy initiatives to create high-value bioproducts while minimizing waste.

LC-HRMS Profiling of Phytochemicals with Assessment of Antioxidant, Anticholinesterase, and Antimicrobial Potentials of Astragalus brachystachys DC.

This study provides the first comprehensive report on the chemical constituents and biological activities of an important medicinal plant, Astragalus brachystachys DC. The aerial part samples were collected from Adana, Türkiye, and an ethanol extract was prepared with these parts. The secondary metabolites of the extract were determined by an LC-HRMS analysis. The LC-HRMS analysis showed the presence of 39 different constituents, hyperoside (303.419±10.50 μg/g extract), p-coumaric acid (256.975±8.51 μg/g extract), and rutin (72.684±2.23 μg/g extract) were determined as major compounds in the aerial parts ethanol extract. Attributed to its high total phenolic (58.53±1.30 μg PEs/mg extract) and total flavonoid content (29.98±0.83 μg QEs/mg extract), the extract demonstrated strong antioxidant activity according to three different assays namely DPPH free (IC50: 33.08±0.61 mg/mL), and ABTS cation radical scavenging (IC50: 15.39±0.72 mg/mL) and CUPRAC activity (A0.5: 36.25±0.28 mg/mL) methods. In vitro assays showed that cholinesterase inhibitory activity results were found to be exceptional with 85.95±0.52 % inhibition on acetylcholinesterase and 66.32±1.33 % inhibition on butyrylcholinesterase at 200 mg/mL. Regarding antimicrobial properties, Astragalus brachystachys DC extract was found to be effective against Enterococcus faecalis with a MIC value of 39.06 μg/mL.

Antioxidant properties and efficient enzymatic synthesis of lipophilic resveratrol monolaurates

Resveratrol (RES) is a natural non-flavonoid polyphenolic antioxidant. The low solubility of RES in water (26 mg/L) and oil (175.51 mg/kg) limited its antioxidant activity and bioavailability. In order to overcome these issues, in this work, a lipophilic resveratrol laurate was efficiently synthesized using RES as starting material in the presence of enzymes. The catalytic activities of enzymes (Lipase CALA, Lipozyme TL 100L, Lipase CALB, Novozym 435, Lipozyme TLIM, and Lipozyme RMIM) were investigated and screened. Moreover, reaction conditions were optimized using response surface methodology. Meanwhile, thermodynamic and kinetic analyses were also conducted to investigate the enzymatic mechanism. Results showed that, Lipozyme RMIM showed the best performance for resveratrol monolaurates regioselective synthesis. Two products, 3-resveratrol monolaurate (3-RC12) and 4′-RC12, were prepared and purified. The optimal reaction conditions for the preparation of 3-RC12, and 4′-RC12 were 1:65 substrate ratio and 11.7 wt% lipase dosage at 75 °C for 33.2 h. Under these conditions, the RES conversion reached a maximum of 98.04 ± 1.76%. The regioselective products were analyzed for antioxidant activity. Notably, the esterification site significantly impacts resveratrol monoesters' antioxidant activity. And 3-RC12 demonstrates superior ABTS and DPPH radical cation scavenging activity, surpassing RES and 4′-RC12. Notably, in yield and antioxidant activity, 3-RC12 is better than 4′-RC12, which make it a potential antioxidant for industrial application.

Recovery of Phenolic Compounds by Deep Eutectic Solvents in Orange By-Products and Spent Coffee Grounds

Orange and coffee grounds by-products, rich in phenolic bioactive compounds, can be used in the food industry as antioxidants, colorants, flavorings and additives, mainly because they are solvents that are easy to prepare, have a lower cost, are thermally stable, biodegradable, renewable, and are considered GRAS (Generally Recognized as Safe). Deep eutectic solvents, which are sustainable and have lower melting points, are effective for extracting these compounds. This study aimed to evaluate the use of deep eutectic solvents (DES) in extracting Total Phenolic Compounds (TPC), from orange by-products and spent coffee grounds. DES formed by citric acid: mannitol (CM-DES), and lactic acid: glucose (LG-DES), were evaluated by varying the following parameters: water content (10–50%), solid–liquid ratio (1:5–1:50 w/w) and temperature (40–50 °C). DES citric acid: mannitol presented the best efficiency in the extraction of TPC under the conditions of 10% water, 80 °C, and solid–liquid ratio 1:10 (w/w) for the orange by-products (1782.92 ± 4.50 mg GAE/L) and 1:15 (w/w) for spent coffee grounds (1620.71 ± 3.72 mg GAE/L). The highest antioxidant activity was observed in the extraction with CM-DES for both by-products in the three methods evaluated: Ferric Reducing Antioxidant Power (FRAP) (1.087 ± 0.004 and 1.071 ± 0.006 mol ascorbic acid/L), DPPH radical scavenging activity (2,2-difenil-1-picrilhidrazil—DPPH) (0.233 ± 0.003 and 0.234 ± 0.001 mol Trolox equivalent/L), and radical cation scavenging activity ABTS (2,2-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid—ABTS) (0.284 ± 7.16 and 0.319 ± 0.002 mol Trolox equivalent/L). Therefore, DES with citric acid: mannitol is a promising alternative to conventional solvents to recover phenolic compounds in agro-industrial by-products, such as orange by-products and SCG.

Solvent Effects on the Phenolic Compounds and Antioxidant Activity Associated with Camellia polyodonta Flower Extracts.

Camellia polyodonta flowers contain limited information available regarding the composition of their bioactive compounds and activity. The objective of this study was to identify phenolic compounds and investigate the effect of different solvents (ethanol and methanol) on the phenolic content and antioxidant activity in C. polyodonta flowers. The analysis using UPLC-Q-TOF-MS/MS revealed the presence of 105 phytochemicals and the most common compounds were flavonols, procyanidins, and ellagitannins. Interestingly, flavonol triglycosides were identified for the first time in these flowers. The study demonstrated that the concentration of the solvent had a significant impact on the total phenolic compound (TPC), total flavonoid compound (TFC), and total proanthocyanidin content (TPAC). The TPC, TFC, and TPAC showed a remarkable increase with the increasing concentration of the solvent, reaching their maximum levels (138.23 mg GAE/g DW, 421.62 mg RE/g DW, 60.77 mg PB2E/g DW) at 70% ethanol. However, the total anthocyanin content reached its maximum at low concentrations (0.49 mg CGE/g DW). Similar trends were observed in the antioxidant activity, as measured by the DPPH· assay (DPPH radical scavenging activity), ABTS·+ assay (ABTS radical cation scavenging activity), and FRAP assay (Ferric reducing antioxidant power). The maximum antioxidant activity was observed at 100% solvents and 70% methanol. Among the 14 individual phenolic compounds, 70% methanol yielded the highest content for 8 (cyanidin-3-O-glucoside, procyanidin B2, procyanidin B4, epicatechin, rutin, kaempferol-3-O-rutinoside, astragaline and quercitrin) out of the 14 compounds. Additionally, it was found that epicatechin was the most abundant phenolic compound, accounting for approximately 20339.37 μg/g DW. Based on these findings, it can be concluded that 70% methanol is the most effective solvent for extracting polyphenols from C. polyodonta flowers. These results provided chemical information and potential antioxidant value for further research in C. polyodonta flowers.

Phenylethanoid glycosides from Michelia champaca leaves

Chemical investigation on the leaves of Michelia champaca L. (Magnoliaceae) led to the isolation of five previously undescribed phenylethanoid glycosides (PhGs), 4-O-β-d-glucopyranosyl-acteoside (1), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-acteoside (2), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-isoacteoside (3), 6""-O-E-feruloyl-echinacoside (4), and 6""-O-p-E-coumaroyl-echinacoside (5), together with eighteen known PhGs. Their structures were determined by spectroscopic and chemical methods. All the known PhGs except acteoside (8) were not previously reported in the genus. Twenty-one PhGs exhibited more potent DPPH radical scavenging activity and FRAP than l-ascorbic acid (l-AA), and twenty-two PhGs showed better ABTS radical cation scavenging activity than l-AA. In addition, twelve PhGs displayed more potent cellular reactive oxygen species scavenging activity than curcumin. The results revealed that the leaves of M. champaca are a rich source of phenylethanoid glycosides and antioxidants.

Antioxidant Activities in Kenaf (Hibiscus cannabinus) Shoots during Growth Stages and Destination of Chlorogenic Acid and Kaempferol Glycosides.

Apart from being utilized as a commercial fiber at maturity, kenaf shoots have potential as a food and feed source because of their diverse bioactivities. Previous studies have focused on mature stems because of their high biomass, whereas the antioxidant activities (AA) and the destination of AA contributors of kenaf stems and their high-yielding byproduct leaves during the growth stage have rarely been studied. Therefore, we investigated changes in AA and its relative components in kenaf leaves and stems during the four vital growth stages. Higher ABTS radical cation and DPPH radical scavenging abilities and ferric reducing antioxidant power, total phenolic content, total flavonoid content, and total polysaccharide content were observed at all leaf stages and in the late stem stages. Chlorogenic acid (CGA) and kaempferol glycosides, especially kaempferitrin (Kfr), were identified as representative phenolic acids and flavonoids in both kenaf leaves and stems. The content of CGA in both leaves and stems increased corresponding to the plant's growth stage, whereas kaempferol glycosides were enhanced in leaves but declined in stems. The highest correlation was observed between TPC and AA in all organs. Further evaluation of CGA and Kfr verified that CGA was the predominant contributor to AA, surpassing Kfr. These findings suggest that kenaf leaves increase antioxidant levels as they grow and can be a useful source of stem harvesting byproducts.

CYTOTOXICITY SCREENING AND ANTIOXIDANT CAPACITY ASSESSMENT OF THE INNER PERIANTH SEGMENTS OF 14 RUMEX SPECIES GROWN IN TÜRKİYE

Objective: Breast cancer is one of the most prevalent cancer types worldwide. Antioxidant sources may prevent the occurrence of cancer. Natural sources rich in phenolics, thus, may provide alternate agents in the management of breast cancer. Rumex species are widely distributed in Turkish flora. Emerging evidence has pointed out the antitumoral property of Rumex species on a variety of cancer cells. In the present study, we propose to test the ethanolic extracts of the inner perianth segments of 14 Rumex species on four breast cancer cells with different origins. We also demonstrated their toxicity on healthy cells. Material and Method: We performed the resazurin reduction assay to examine the cytotoxicity and toxicity. Furthermore, we determined the phenolic contents of the extracts as an indicator of their antioxidant profile and ascertained their antioxidant activities by DPPH radical, ABTS radical cation scavenging activity and cupric ion-reducing antioxidant capacity assays. Result and Discussion: The ethanolic extracts of the inner perianth segments of Rumex species exhibited remarkable cytotoxicity profiles neither on breast cancer cells nor on healthy H9c2 rat myoblastoma cells. However, they usually displayed strong antioxidant activities due to possessing high phenolic content.

Flavonoid glycosides from the leaves of Michelia champaca

Michelia champaca L. (Magnoliaceae) was cultivated in large scale for flowers as cosmetic raw materials, whereas the value of its leaves remains to be discovered. Our chemical study on the leaves yielded four new flavonol diglycosides, champaflavosides A–D (1–4), together with twenty-three known flavonoid glycosides (5–27). Their structures were determined by spectroscopic and chemical methods. Compounds 5–21 and 23–27 were not previously reported from the genus Michelia, and kaempferol 3-O-rutinoside (22) was obtained from this species for the first time. All the compounds were evaluated for antioxidant activity by four in vitro assays. Compounds 3–12 and 20 showed more potent 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity than l-ascorbic acid (l-AA). Compounds 2–23, 25, and 27 exhibited 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical cation scavenging activity superior to l-AA. The ferric reducing antioxidant powers (FRAP) of compounds 2–13, 17, and 19 were higher than l-AA. Further, eighteen compounds demonstrated cellular reactive oxygen species (ROS) scavenging activity, of which champaflavoside D (4), rhamnetin 3-O-neohesperidoside (8), quercetin 3-O-(6-O-E-p-coumaroyl)-neohesperidoside (9), and liquiritin (27) were more potent than curcumin. The results revealed that the renewable leaves of M. champaca are a rich source of flavonoids and antioxidants.

Comparative Evaluation of Antioxidant Activity in Extracts and Fractions from Leaves and Stem of Geophila obvallata (Schumach.) Didr

Background: Oxidative stress, a condition characterized by an imbalance between reactive oxygen species (ROS) and antioxidant defences, is increasingly implicated in various human diseases. Medicinal plants with potent antioxidant properties hold promise for therapeutic interventions against oxidative stress-related pathologies. This study aimed to comparatively evaluate the antioxidant potential of leaf and stem extracts and fractions derived from Geophila obvallata. Methods: Methanolic extracts of G. obvallata leaves and stems were subjected to solvent partitioning to obtain fractions based on polarity. Total phenolic content (TPC) and total flavonoid content (TFC) were determined. The antioxidant capacities of the extracts and fractions were assessed using established assays, including hydroxyl radical scavenging (HRSA) and ABTS+ cation radical scavenging. Results: The highest concentrations of phenolics (86.35 and 79.72 mg/g tissue gallic acid equivalents – GAE) and flavonoids (67.56 and 64.92 mg/g tissue quercetin equivalents – QE) were observed in the leaf and stem methanol extracts, respectively. Remarkably, the antioxidant activity of both leaf and stem methanol fractions surpassed that of the standard controls (ascorbic acid, α-tocopherol, and trolox). The antioxidant capacity exhibited a decreasing trend across the various extracts and fractions, following the order: methanol > 1-butanol > chloroform > benzene > ethyl acetate > n-hexane > aqueous. These findings suggest superior free radical scavenging abilities in the leaf extracts and fractions compared to the controls.Conclusion: This investigation unveils the significant antioxidant potential of G. obvallata leaf extracts, highlighting their potential efficacy in combating diseases associated with oxidative stress. These findings warrant further exploration to elucidate the underlying mechanisms of action and validate their therapeutic potential in vivo models.

Chemical Composition and Antioxidant Activity of Essential Oil from Fresh and Dried Leaves of Echinops adenocaulos Boiss. from Jordan

Abstract: This study presents the first detailed analysis of hydrodistilled essential oils from fresh and air-dried Echinops adenocaulos Boiss. from the flora of Jordan. It aims to investigate the chemical composition and the antioxidant potency of the volatile compounds obtained by conventional hydrodistillation from the fresh and air-dried plant; gas chromatography-mass spectrometry analysis identified 46 and 75 compounds of the obtained essential oils, respectively. The study showed that the major constituent classes in the fresh aerial part are oxygenated diterpenes (76.92%) and oxygenated sesquiterpenes (10.78%), followed by aliphatic compounds (10.12%). However, in the dried aerial part, the main classes are oxygenated diterpene (74.47%) and aliphatic compounds (13.34%). Heyderiol was the most abundant constituent (44.96%), followed by bis(2-ethylhexyl)phthalate (20.12%) and trans-ferruginol (3.14%). Bis(2-ethylhexyl)phthalate (52.51%), followed by heyderiol (21.60%) and (Z)-ternine (8.81%) are the major compounds of the fresh aerial part. The antioxidant activity was tested by DPPH free radical scavenging and ABTS•+ cation radical scavenging. The oils from fresh and dried E. adenocaulos exhibit significant antioxidant activity, with the oil from the dried plant having higher antioxidant activity than that from the fresh one.

Comparative Antioxidant and Antimicrobial Activities of Several Conifer Needles and Bark Extracts.

Nowadays, an increased concern regarding using natural products for their health benefits can be observed. The aim of this study was to assess and compare several phenolic compounds found in 15- to 60-year-old Douglas fir, silver fir, larch, pine, and spruce needle and bark extracts and to evaluate their antioxidant and antimicrobial activities. Spectrophotometric assays were used to determine the total polyphenol content and the antioxidant activity that was assessed by using the DPPH• radical scavenging assay (RSA), the ferric reducing antioxidant power assay (FRAP), and the ABTS•+ radical cation scavenging assay (ABTS). The phytochemical content was determined by using high-performance liquid chromatography, and the antimicrobial activity was determined by assessing the minimal inhibition concentration (MIC). The results of the study show a total polyphenol content of 62.45-109.80 mg GAE/g d.w. and an antioxidant activity of 91.18-99.32% for RSA, 29.16-35.74 µmol TE/g d.w. for FRAP, and 38.23-53.57 µmol TE/g d.w. for ABTS. The greatest quantity of phenolic compound for most of the extracts was for (+)-catechin, and it had values between 165.79 and 5343.27 µg/g d.w. for these samples. The antimicrobial inhibition for all the extracts was the strongest for Staphylococcus aureus (MIC 62.5-125 µg/mL). The extracts analyzed could be used for their bioactive potential after further investigations.

Synthesis and Antioxidant Activity of Novel Thiazole and Thiazolidinone Derivatives with Phenolic Fragments

In this work, a series of thiosemicarbazones with phenol fragments were used as starting compounds for the synthesis of new effective antioxidants containing both a phenol substituent and a heterocyclic fragment: thiazole and thiazolidinone. To determine the most stable conformation of thiosemicarbazone, a potential energy scan was used, along with NOESY NMR spectroscopy data. A number of thiazole derivatives were obtained due the interaction of thiosemicarbazones with several bromoketones: bromoacetophenone, bromodimedone, and bromoacetylcoumarin. The product yields varied from 71 to 94%. Thiazolidinone derivatives were obtained through the reaction between thiosemicarbazones and chloroacetic acid or maleic anhydride with good yields of 82–95%. The antioxidant activities of all the products were determined in vitro: the radical cation scavenging activity was estimated using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate), while the ferric reducing capacity was determined using the ferricyanide/Prussian blue method. It was found that the antioxidant activity of most synthesized substances in both tests exceeds the activity of 4-methyl-2,6-di-tert-butylphenol, while derivatives with a fragment of 2,6-di-tert-butylphenol have the highest activity.

Antioxidant activity, anti-tyrosinase activity, molecular docking studies, and molecular dynamic simulation of active compounds found in nipa palm vinegar.

Tyrosinase is a key enzyme in melanogenesis and its inhibitors have become increasingly because of their potential activity as hypopigmenting agents which have less side effects. Nipa palm vinegar is an aqueous product that is normally used as a food supplement. The aim of this study was to study the determination of antioxidant activity and tyrosinase inhibitory activities of aqueous extract of original nipa palm vinegar (AE O-NPV), nipa palm vinegar powder (NPV-P) and aqueous extract of nipa palm vinegar powder (AE NPV-P) were examined. Nipa palm vinegars were evaluated the phenolic and flavonoid content, and the active compounds which were submitted to molecular docking and molecular dynamic simulation, chemoinformatics, rule of five, skin absorption and toxicity. The highest phenolic and flavonoid contents in the AE O-NPV were 2.36 ±0.23 mg gallic acid equivalents/g extract and 5.11 ±0.59 mg quercetin equivalents/g, and the highest ABTS radical cation scavenging activity was also found. The AE O-NPV, NPV-P and AE NPV-P showed anti-mushroom tyrosinase activity. The HPLC analysis showed that there were vanillic acid and three flavonoids (catechin, rutin and quercetin). The molecular docking study revealed that the binding of the vanillic acid and three flavonoids occurred in the active site residues (histidine and other amino acids). Moreover, the number of hydrogen bond acceptors/donors, solubility, polar surface area and bioavailability score of the vanillic acid and three flavonoids were acceptable compared to Lipinski's Rule of Five. The molecular dynamic simulation showed that vanillic acid interacts with HIS284 through π-π stacking hydrophobic interactions and forms a metal-acceptor interaction with the copper molecule at the tyrosinase active site. All compounds revealed good skin permeability and nontoxicity. Nipa palm vinegar could be a promising source of a new ingredient for tyrosinase inhibition for cosmetics or pharmaceutical products.

Widely targeted metabolomics analysis of the main bioactive compounds of Ganpu tea processing through different drying methods

The flavor and biological components of Ganpu tea are largely affected by the drying process. In this study, Ganpu tea was selected as the research object, and the effects of different drying methods, including drying by sunlight, low temperatures and hot air, on the antioxidant activities, α-glucosidase and acetylcholinesterase activities and metabolite profiles of Ganpu tea were investigated. The results suggested that the DPPH free radical scavenging activities of low temperature-dried Ganpu tea (GPTL), sunlight-dried Ganpu tea (GPTS) and hot air-dried Ganpu tea (GPTH) were 46.8%, 56.2% and 47.1%, respectively. The ABTS radical cation scavenging activity of GPTL, GPTS and GPTH were 45.2%, 51.4% and 46.3%, and the T-AOC activities among them were 14.3, 21.4 and 12.5 U/g, respectively. In addition, compared with GPTS and GPTH, GPTL increased α-glucosidase inhibition and acetylcholinesterase inhibition activities. The widely targeted metabolomics analysis showed that low-temperature drying significantly increased corilagin and strictinin levels, which played an important role in the antioxidant activities of Ganpu tea. The results provide a novel method for drying Ganpu tea and help promote the quality control of Ganpu tea during processing.

Chemical characterization, antioxidant, antimicrobial, enzyme inhibitory and cytotoxic activities of Illicium lanceolatum essential oils

Illicium lanceolatum is a medicinal and aromatic plant widely distributed in the south of China. The reports on chemical composition and biological activities of its essential oils (EOs) were very limited. In this study, Illicium lanceolatum EOs were extracted by hydro distillation, and analyzed by GC–MS and GC-FID. DPPH radical scavenging assay, ABTS cation radical scavenging assay and ferric reducing/antioxidant power (FRAP) assay were used for antioxidant activity evaluation. Minimum inhibitory concentrations (MICs) and minimum microbiocidal concentrations (MMCs) against 9 microorganisms were determined. The inhibitory effects on tyrosinase, α-glucosidase and cholinesterases were evaluated and cytotoxic activities were evaluated using MTT assay. The results revealed 110 identified compounds, with asaricin, eucalyptol, linalool and caryophyllene oxide as major compounds. Eucalyptol was the most abundant compound in the stem, leaf and fruit EOs while asaricin accounted for 50.52 ± 0.33 % in the root EO. Very weak radical scavenging capacities were noticed for all EOs, but the root EO showed moderate antioxidant activity (176.33 ± 4.52 mg TE/g of EO) in the FRAP assay, which could be attributed to asaricin. The root EO displayed better antimicrobial activities than other three EOs, with MIC values as 3.13 mg/mL against three bacteria including Staphylococcus aureus BNCC 186335, Bacillus cereus BNCC 103930 and Listeria monocytogenes BNCC 336877. Camphor and borneol were found to be important antimicrobial compounds. No inhibitory effect on α-glucosidase was found. The leaf EO displayed better acetylcholinesterase inhibitory activity (17.79 ± 0.32 mg GE/g of EO) while the root EO showed better tyrosinase (30.34 ± 0.40 mg KAE/g of EO) and butyrylcholinesterase (43.25 ± 1.50 mg GE/g of EO) inhibitory activities. Molecular docking between active compounds and enzymes revealed the main interactions as hydrophobic interaction, hydrogen bond and π-stacking. All EOs displayed weak cytotoxicity to HK-2 cells of normal kidney at six tested concentrations. The leaf EO showed strong anticancer activities to HepG2 cells at the concentration of 500 μg/mL. I. lanceolatum EOs showed promising prospects with possible applications in pharmaceutical and cosmetic industries.