Evaluation of the antioxidant and antibacterial properties of various solvents extracts of Annona squamosa L. leaves

The present work was conducted aiming to evaluate the effect of different solvent extracts on the antioxidant and antibacterial activities of Annona squamosa L. leaves. Four solvents were chosen for the study namely; methanol 80%, acetone 50%, ethanol 50% and boiling water. Acetone and boiling water gave the highest extraction yields as compared to methanol and ethanol. Total phenolic contents of the four extracts were significantly different with acetone being the most efficient solvent and water being the least efficient one. Correlation coefficient between the total antioxidant and total phenolic content was found to be R² = 0.89 suggesting the contribution of phenolic compounds of the extract by 89% to its total antioxidant activity. The extracts were capable of scavenging H₂O₂ in a range of 43–54%. Reducing power of the extracts increased by increasing their concentration. The extracts were found to exert low to moderate antibacterial activity compared to a standard antibacterial agent. The bacterial inhibition of the extracts was found to positively correlate with their phenolic contents.     

Antioxidant activity of clove oil – A powerful antioxidant source

The number of methods to measure the antioxidants in botanicals, foods, nutraceuticals and other dietary supplements has increased considerably in the last decade. Clove oil is obtained by distillation of the flowers, stems and leaves of the clove tree. In the present paper, clove oil was evaluated by employing various in vitro antioxidant assay such as α,α-diphenyl-β-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe³⁺–Fe²⁺ transformation method, superoxide anion radical scavenging by riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe²⁺) chelating activities. Clove oil inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15 μg/mL concentration. However, under the same conditions, the standard antioxidant compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox demonstrated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45 μg/mL concentration, respectively. In addition, clove oil had an effective DPPH scavenging, ABTS⁺ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe³⁺) reducing power and ferrous ions (Fe²⁺) chelating activities. Also, these various antioxidant activities were compared to BHA, BHT, α-tocopherol and trolox as reference antioxidant compounds.     

Radical scavenging and antioxidant activity of tannic acid

Tannic acid, a naturally occurring plant polyphenol, is composed of a central glucose molecule derivatized at its hydroxyl groups with one or more galloyl residues. In the present paper, we examines the in vitro radical scavenging and antioxidant capacity of tannic acid by using different in vitro analytical methodologies such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination using by Fe³⁺–Fe²⁺ transformation method, superoxide anion radical scavenging by riboflavin–methionine-illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe²⁺) chelating activities. Also, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as the reference antioxidant radical scavenger compounds.Tannic acid inhibited 97.7% lipid peroxidation of linoleic acid emulsion at 15 μg/mL concentration. On the other hand, the above mentioned standard antioxidants indicated an inhibition of 92.2%, 99.6%, 84.6% and 95.6% on peroxidation of linoleic acid emulsion at 45 μg/mL concentration, respectively. In addition, tannic acid had an effective DPPH scavenging, ABTS⁺ radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, Fe³⁺ reducing power and metal chelating on ferrous ions activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and trolox as references antioxidant compounds. The present study shows that tannic acid is the effective natural antioxidant component that can be used as food preservative agents or nutraceuticals.     

Gas Chromatography-Mass Spectroscopic,high performance liquid chromatographic and In-silico characterization of antimicrobial and antioxidant constituents of Rhus longipes (Engl)

Rhus longipes is one of those underutilized plant species with inherent values. Therefore, we conducted a phytochemical study and investigated the antioxidant and antimicrobial potentials of the plant extracts. Aqueous and ethanol extract was subjected to phytochemical analysis. Gas chromatography-mass spectroscopy was performed to identify the volatile compounds while high performance liquid chromatography was done to identify the phenolic and flavonoids in the ethanol extract. Bioactivity and molecular docking analysis was also done for the identification of the bioactive constituents. Tannins, flavonoids, phenolics, terpenoids, steroids, alkaloids, and saponins were identified both in the ethanol and in aqueous extracts of R. longipes. The extracts and ascorbic acid exhibited radical inhibition in a concentration dependent manner. The IC₅₀ values; 3.23, 4.13, 70.75 µg/mL (ABTS), 200.82, 103.63, 390.83 µg/mL (DPPH), 10.06, 93.46, 253.26 µg/mL (O₂), and 99.77, 109.23, 446.34 µg/mL (NO) for ascorbic acid, ethanol and aqueous extract respectively showed that ethanol extract exhibited better radical inhibition than the aqueous extract. 4-hydroxybenzoic and 4-hydroxycoumarin were the most abundant phenolics in the extract. The ethanol extract of R. longipes demonstrated broad-spectrum antibacterial activity with inhibition zone of 25.5 mm against S. aureus, 27.5 mm against E. coli, and 20.5 mm against P. aeruginosa. The identified phytochemicals demonstrated inhibitory potentials against bacterial glucosamine 6-phosphate synthase, penicillin-binding protein 3, DNA gyrase and β-lactamase. It is evident that R. longipes have some antioxidant and antibacterial properties and the plant contain important phytochemicals with ability to retard food oxidation and deterioration and thus could be annexed for various industrial and medicinal purposes.     

Bioinspired synthesis of pure massicot phase lead oxide nanoparticles and assessment of their biocompatibility,cytotoxicity and in-vitro biological properties

Green and ecofriendly route for biosynthesis of lead oxide nanoparticles has been successfully demonstrated using aqueous leaf extracts of Sageretia thea (Osbeck.). Biosynthesized PbO (∼27 nm) nanoparticles were extensively characterized using XRD, FTIR, Raman, EDS etc. Morphology was studied through HR-TEM/SEM. As synthesized nanoparticles were investigated for their iv-vitro biological properties. Antibacterial activities revealed enhancement upon modulation by UV in a concentration dependent manner. Pseudomonas aeruginosa was found to be the most resistant strain (MIC = 250 µg/mL and MIC^uv = 31.25 µg/ml). MTT cytotoxicity on leishmania promastigotes and amastigotes revealed significant inhibition as indicated by their IC₅₀ values of 14.7 µg/mL and 11.95 µg/m respectively. Cytotoxicity was also confirmed using brine shrimp lethality (IC₅₀ = 27.7 µg/mL). Bio-compatibility evaluation indicated cytotoxicity to freshly isolated human macrophages (IC₅₀ = 57.1 µg/mL). Insignificant alpha-amylase inhibition and moderate protein kinase inhibition was revealed. Antioxidant activities indicated free radical scavenging activity (58 ± 2.45) at 200 µg/mL. Moderate total reducing power and total antioxidant activity was also indicated. Overall, we conclude lead oxide as a potential candidate for biological applications, however further studies are recommended on their in vitro and in vivo cytotoxicity.     

Chemical composition and biological potential of seed oil and leaf extracts of Henophyton deserti Coss. & Durieu

Henophyton deserti was characterized in respect to its chemical composition, antioxidant potential and antimicrobial activity. Fourteen compounds were identified by LC/MS, GC/MS, and GC in leaf and seed extracts. Total flavonoids ranged between 45.66 and 181.2 mg QE g^?1 and 2.03 and 38.95 mg QE g^?1 dry weight (dw) in leaf and seed polar extracts, respectively. Rutin, Kaempferol 3-rutinoside, Diosmetin 7-O-Glucoside, and Acacetin 7-O-Glucoside flavonoids were tentatively identified in this plant. The profile of seed fatty acids revealed oleic acid (C18:1, 27%), linoleic acid (C18:2, 12%) and linolenic acid (C18:3, 17%). The highest antioxidant activities of 85.2% and 67.5% were obtained with methanol and ethyl acetate leaf extracts. All H. deserti extracts were active against at least one of the tested bacteria, leaf ethyl acetate extract showed the lowest MIC of 0.156 mg ml^?1. Only seed ethyl acetate extract showed antifungal activity with a MIC of 2.5 mg ml^?1.     

Chemical composition and antioxidant, α-glucosidase inhibitory and antibacterial activities of three Echeveria DC. species from Mexico

Three Echeveria species from Sinaloa, Mexico (Echeveria craigiana, Echeveria kimnachii and Echeveria subrigida) were analyzed for their content of antioxidant compounds (β-carotene, ascorbic acid, α-tocopherol, total phenolics and flavonoids) and the in vitro antioxidant (DPPH, ABTS, ORAC and β-carotene bleaching [β-CBM]), α-glucosidase inhibitory and antibacterial activities. The studied Echeveria species showed high α-tocopherol content (2.9–9.0 mg/100 g f.w.) and total phenolics as Gallic Acid Equivalents (GAE) (152.2–400.5 mg GAE/100 g f.w.). Antioxidant activities of the three Echeveria methanol extracts (ME) were higher than those of other well-known plants with this property; the activities of E. craigiana (ABTS, 65.91 μmol ET/g f.w.) and E. subrigida (β-CBM, 79.3%) were remarkable. The Echeveria ME showed stronger α-glucosidase inhibition (IC₅₀ 25.21–50.57 μg/mL) than acarbose (IC₅₀ 3.59 mg/mL) as well as high antibacterial activity (Minimal Inhibitory Concentrations, MICs ⩽ 1 mg/mL), mainly against Gram positive bacteria. The results showed the three Echeveria species had components/biological activities with high potential for food/pharmacological uses and could be exploited by sustainable management schemes.     

Effect of gamma irradiation on the antimicrobial and free radical scavenging activities of Glycyrrhiza glabra root

The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25 kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the present study showed that radiation treatment up to 20 kGy does not affect the antifungal and antibacterial activity of the plant. While sample irradiated at 25 kGy does showed changes in the antibacterial activity against some selected pathogens. No significant differences in the phenolic contents were observed for control and samples irradiated at 5, 10 and 15 kGy radiation doses. However, phenolic contents increased in samples treated with 20 and 25 kGy doses. The DPPH scavenging activity significantly (p<0.05) increased in all irradiated samples of the plant.     

Radiation hydrolysate of tuna cooking juice with enhanced antioxidant properties

Tuna protein hydrolysates are of increasing interest because of their potential application as a source of bioactive peptides. Large amounts of tuna cooking juice with proteins and extracts are produced during the process of tuna canning, and these cooking juice wastes cause environmental problems. Therefore, in this study, cooking juice proteins were hydrolyzed by irradiation for their utilization as functional additives. The degree of hydrolysis of tuna cooking juice protein increased from 0% to 15.1% at the absorbed doses of 50 kGy. To investigate the antioxidant activity of the hydrolysate, it was performed the ferric reducing antioxidant power (FRAP) assay, and the lipid peroxidation inhibitory and superoxide radical scavenging activities were measured. The FRAP values increased from 1470 μM to 1930 μM and IC₅₀ on superoxide anion was decreased from 3.91 μg/mL to 1.29 μg/mL at 50 kGy. All of the antioxidant activities were increased in the hydrolysate, suggesting that radiation hydrolysis, which is a simple process that does not require an additive catalysts or an inactivation step, is a promising method for food and environmental industries.     

Effect of electron-beam irradiation on the antioxidant activity of extracts from Citrus unshiu pomaces

After electron-beam irradiation of citrus pomaces (CP), the total phenolic content (TPC), radical scavenging activity (RSA), and reducing power (RP) were evaluated. When CP were irradiated at 37.9 kGy; the TPC, RSA and RP of water extract of CP increased from 6543.2 to 7405.4 μM, 37.6% to 52.9%, and 0.64 to 0.90, respectively, compared with the non-irradiated control. The results indicate that the electron-beam irradiation can be an efficient process for increasing the antioxidant activity of CP.     

HPLC–DAD–MS identification of polyphenols from Passiflora leschenaultii and determination of their antioxidant,analgesic, anti-inflammatory and antipyretic properties

Passion fruit (Passiflora leschenaultii DC), an endemic species to peninsular India, is traditionally used to treat various ailments such as dysentery, urinary stone disease and wounds. The present study aimed to investigate the antioxidant, analgesic, anti-inflammatory, antipyretic activities and chemical composition of leaf extracts of P. leschenaultii. Bioactive secondary metabolites such as total phenolics, tannins and flavonoids were quantified. Antioxidant activities were determined by DPPH, ABTS⁺, FRAP, metal chelating and phosphomolybdenum assays. Hot plate, acetic acid and formalin induced pain models were used to evaluate the analgesic activity. In order to study the acute and chronic anti-inflammatory activities, carrageenan and cotton pellet induced models were used in rats. Brewer’s yeast induced pyrexia method was applied for the antipyretic test. Functional compounds from the plant were identified and quantified through HPLC–DAD–MS analysis. The obtained results revealed that the acetone extract of leaves exhibited higher phenolic (440.24 mg GAE/g extract) and flavonoid (253.33 mg RE/g extract) contents and scavenged the DPPH (IC₅₀ 29.14 μg/mL), ABTS⁺ (10509.69 μM TEAC/g extract) effectively. On investigating the analgesic, anti-inflammatory and antipyretic activities, the acetone extracts of leaves, at a dose of 400 mg/kg (p.o.) reduced significantly (p < 0.001) the pain, inflammation and fever responses in vivo. Bioactive compounds such as hyperin, chlorogenic acid, rutin and caffeic acids were identified in the leaves of P. leschenaultii employing HPLC–DAD–MS analysis. These findings illustrate the excellent potential of this species as valuable source of natural phytochemicals with pharmacological properties.     

Antioxidant and α-Glucosidase Inhibitory Compounds of Centella Asiatica

Centella asiatica, as known as Pegagan was previously reported to have anti-hyperglycemic effects in animal diabetic model rats. However, its α-glucosidase activity in vitro assay not yet reported. Our goal in this study is to isolate and identify active compounds as α-glucosidase inhibitor and antioxidant from aqueous ethanol 70% (v/v) extract of C. asiatica. The extract was partitioned by n-hexane, EtOAc, and n-butanol sequentially. Among the fractions tested, EtOAc fraction was showed the highest antioxidant and α-glucosidase inhibitory activities with an IC₅₀ values of 45.42 and 73.17 μg/mL, respectively. The antioxidant activity was conducted by determination of DPPH radical scavenging activity, whereas α-glucosidase inhibitory activity was determined against yeast α-glucosidase. Furthermore, isolation of the ethyl acetate extract yielded two active compounds, which were identified as kaempferol (1) and quercetin (2). Both of the compounds showed good yeast α-glucosidase inhibitory activity with IC₅₀ values of 16.50 and 21.61 μg/mL, respectively. In addition those compounds also could scavenge DPPH radical activity with IC₅₀ values of 9.64 and 11.97 μg/mL, respectively. Due to its ability in reducing α-glucosidase activity and scavenging free radical activity, the C. asiatica appears to be a potential as a good resource for future development of antioxidant and antidiabetic drug.     

Gamma radiation effects on physico-chemical parameters of apple fruit during commercial post-harvest preservation

The physico-chemical parameters (including moisture, total soluble solids, antioxidant activity, phenolic content and firmness) of cv. Red Delicious apple subjected to γ radiation were evaluated for their ability to avoid the post-harvest blue mold caused by Penicillium expansum during cold storage. Freshly harvested apples were inoculated with P. expansum. Treated fruits were irradiated at doses of 0, 300, 600, 900 and 1200 Gy and stored at 1 °C. Apples were evaluated at three month intervals. The results showed that there was a clear link between phenolic content and antioxidant activity, so that dose range of 900 Gy and higher significantly decreased phenolic content and antioxidant activity. The moisture percent of stored apples was more responsive to irradiation (at doses of 900–1200 Gy) than storage time and pathogen. Lesion diameter of pathogen-treated non-irradiated apples was significantly increased after three months. This means that storage at low temperature is not enough to avoid blue mold growth. As dose and storage time increased firmness decreased; also pathogen accelerated softening of stored apples. This study showed conclusively that low irradiation doses (300 and 600 Gy) combined with cold storage is a way to minimize apple quality losses during nine month storage period.     

CO2 adsorption on granular and monolith carbonaceous materials

We evaluated the CO₂ adsorption capacity on granular and monolith carbonaceous materials, obtained by chemical activation of African palm stones with H₃PO₄, ZnCl₂ and CaCl₂ solutions at different concentrations. Textural properties of the synthesized materials were analyzed using N₂ adsorption measurements at 77 K, the isotherms showed obtaining of materials microporous and moderately mesoporous, with surface areas between 161 and 1700 m²/g and pore volume between 0.09 and 0.64 cm³ g⁻¹. Were observed different behaviors for textural parameters in each series, associated with the activating agent used in the preparation. The materials obtained have a CO₂ adsorption capacity between ∼114 and 254 mg CO₂/g, at atmospheric pressure and 273 K. It was established that the total amount of CO₂ adsorbed under these experimental conditions is defined by the narrow micropore volume (V_n) and increased the total basicity of the materials.     

Ruellia prostrata Poir. activity evaluated by phytoconstituents,antioxidant, anti-inflammatory,antibacterial activity,and in silico molecular functions

Ruellia prostrata Poir. has been used historically as an anti-cancer, wound healing agent and to treat gonorrhea. We aimed to determine the phytochemicals present in ethyl acetate extract of R. prostrata Poir. (EAERP). We sought to determine the antioxidant, anti-inflammatory, and antibacterial activities in vitro, and toxicity properties in vivo. We also analyzed the Prediction of Activity Spectra for Substances (PASS), physicochemical, ADMET, and drug-likeness properties of phytochemicals in EAERP. To determine phytoconstituents, preliminary phytochemical screening and GC–MS were performed, while FT-IR was used to identify functional groups. The antioxidant activity was evaluated using a DPPH scavenging assay, whereas BSA denaturation and RBC hemolysis inhibition were used to assess anti-inflammatory activity. An agar-well-diffusion assay was performed to estimate the antibacterial activity. Brine shrimp lethality bioassay and oral delivery of EAERP of single-dose were performed to determine cytotoxicity and acute toxicity, respectively. The phytochemical screening revealed the presence of phenols, triterpenoids, saponins, steroids, amino acids, and fat and fixed oils. FT-IR analysis of EAERP showed the presence of many functional groups: alcohols/phenols, carboxylic acids, aldehydes, alkanes, esters, amines, amides, aromatic hydrocarbons, sulfoxides, and alkyl halides. GC–MS revealed the presence of 39 phytoconstituents including steroids, consistent with compounds and functional groups found in preliminary screening and FT-IR. EAERP showed dose-dependent antioxidant activity with an IC₅₀ value of 21.402 µg/mL and anti-inflammatory activity with an IC₅₀ value of 20.564 µg/mL in RBC hemolysis inhibition and 21.115 µg/mL in BSA denaturation assays. EAERP also exhibited dose-related antibacterial activity. EAERP exerted cytotoxicity with an LC₅₀ value of 17.619 μg/mL and acute toxicity with an LD₅₀ value of 4095.328 mg/kg without any adverse effects. The PASS server also predicted that the phytoconstituents of EAERP have antioxidant, anti-inflammatory, and antibacterial activities with probable activity (Pa) ranging from 0.310 to 0.717. Analysis of physicochemical, ADMET, and drug-likeness properties revealed the drug-able efficacy and safety of most compounds. The findings of this study indicated that R. prostrata Poir. contains phytoconstituents with potent antioxidant, anti-inflammatory, and antibacterial activities. Taken together, our measurements suggest that R. prostrata Poir. is a prime candidate for further exploration as a potential therapeutic agent.     

Aluminum chloride-functionalized silica gel synthesis as a catalyst for the preparation of biologically active oxazolidinethiones: Antioxidant and molecular docking studies

The aim of this research paper was the preparation of aluminum chloride bonded to silica gel catalyst and its application in the modification of steroidal molecules. Steroidal oxazolidinethiones were prepared using silica-supported aluminum chloride (SiO₂-AlCl₃) under Microwave irradiation, which is common in organic synthesis to achieve high yields in shorter reaction times. The advantage of this method is that the usual procedure can be carried out without tiring and without a secondary product at the end of the reaction. Physicochemical techniques were used to identify the chemical structure of the prepared oxazolidinethiones. A rationalization of the conversion pathways from steroidal epoxides to oxazolidinethiones is sketched on the basis of current and previous results. Antioxidant activities i.e. DPPH assay, total antioxidant capacity and total reductive capability were performed for steroidal compounds, including reactants, and the results indicated that steroidal oxazolidinethione with acetoxy group had a promising activity among the tested steroids. In correlation with antioxidant activity, a promising steroid derivative was subjected to a molecular docking study for binding to tyrosine kinases, the target protein and showed a negative binding energy −7.8 Kcal/mol suggesting good affinity to the active pocket and can be considered as a better antioxidant in the biological system.     

An FT-IR study of the isomerization of 1-butoxy radicals under atmospheric conditions

Relative rate-studies of the reactions of 1-butoxy radicals have been carried out using a 47 L static reactor with detection of end products by FT-IR spectroscopy. Experiments were performed at 700 torr total pressure and over the temperature range 253–295 K. The chemistry of 1-butoxy is characterized by a competition between reaction with oxygen CH₃CH₂CH₂CH₂O + O₂ → n-C₃H₇CHO + HO₂ (R2), which yields butanal and isomerization CH₃CH₂CH₂CH₂O → CH₂CH₂CH₂CH₂OH (R3), to form a hydroxylated carbonyl-product. A reference spectrum attributed to the product of 1-butoxy isomerization was obtained and used to determine the competition between 1-butoxy isomerization versus reaction with oxygen. The results indicate that isomerization is the dominant fate of 1-butoxy radicals at ambient temperature and pressure and that its importance decreases with decreasing temperature. The rate-coefficient ratio k₃/k₂ (molecule cm⁻³) = 5.5 × 10²³ exp[(−25.1 ± 0.9 kJmol⁻¹)/RT] was obtained. This agrees with other estimates based on methods without monitoring of the isomerization product.     

Efficient green extraction of polyphenols from post-harvested agro-industry vegetal sources in Piedmont

A study of the polyphenols content and antioxidant capacity of grapevine waste and hazelnut skins (roasted material) from post-harvest products that originate from Piedmont (Italy) has been carried out and the results herein presented. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) were used to achieve process intensification in shorter extraction times, with lower environmental impact and higher selectivity compared to classic maceration. Besides classic solvents, the aqueous β-cyclodextrin solution (1.5%) showed to be an excellent extraction medium for grapevine waste. Total phenolic content (TP) from grapevine waste ranged from 18.23 ± 2.4 to 198 ± 3 mg gallic acid equivalents (GAE)/g dry weight, while total antioxidant capacity (TAC) expressed as EC₅₀ ranged from 0.0902 ± 0.08 mg/mL to 0.0041 ± 0.02 mg/mL. For hazelnut skins, TP ranged from 61.68 ± 0.8 to 200.79 ± 3.0 mg GAE/g dry weight, while TAC ranged from 0.0021 ± 0.0004 to 0.0002 ± 0.0001 mg/mL extract. We have shown that, compared to maceration, the use of UAE and MAE methods can enhance polyphenols recovery and antioxidant capacity.