Highest DPPH Radical Scavenging Research Articles

Utilization of undesirable heat-induced precipitates/sediments in soy sauce production to fabricate nanoparticles for curcumin delivery

This study aimed to utilize an unwanted by-product of soy sauce production, the heat-induced precipitates/sediments (HPSS), to fabricate HPSS nanoparticles using a pH-driven method for their use as nano-carriers of unstable curcumin. The results showed that curcumin could successfully complex with HPSS at pH 6.0, 7.0 and 8.0, via hydrogen bonding, electrostatic interactions and hydrophobic interactions, with high encapsulation efficiency (>96%), stability and DPPH radical scavenging activity. Comparable properties were found among the HPSS nanoparticles and derived HPSS-curcumin nanocomplexes obtained at the three pHs, although the HPSS nanoparticles had the highest curcumin loading amount (10.14 μg/mg) and greatest DPPH radical scavenging power (SC50 0.89 μg/mL) at pH 7.0, and the nanocomplexed curcumin was most stable at pH 6.0. Thus, HPSS can be utilized as delivery vehicles for hydrophobic substances in food and medicinal applications, and pH is a critical variable governing the outcomes.

The health benefits of three Hedgenettle herbal teas (Stachys byzantina, Stachys inflata, and Stachys lavandulifolia) - profiling phenolic and antioxidant activities

IntroductionPlants belonging to the genus Stachys have been used in traditional medicine due to their various properties. The potential health benefits of three widely consumed Stachys decoctions (S. byzantina, S. inflate and S. lavandulifolia) were profiled in terms of their phenolic compounds and antioxidant properties, MethodsReverse-phase high-performance liquid chromatography- diode array detector (RP-HPLC-DAD) analysis for phenolics profiling was carried out. Moreover, comprehensive antioxidant ability and several key enzymes inhibitory activity of decoctions were investigated. Results14 phenolic components were quantified in the samples in which chlorogenic acid (6228 μg/g decoction), (+)-catechin (504 μg/g decoction), and rosmarinic acid (460 μg/g decoction) were found to be the major bioactive compounds. S. inflata showed high DPPH radical scavenging potential (141 mg Trolox equivalents/g decoction) and S. byzantina indicated excellent radical scavenging activity in ABTS (330 mg TE/g decoction) assay. Also, all decoctions exhibited strong reducing power in CUPRAC (280−363 mg TE/g decoction) and FRAP (270−312 mg TE/g decoction) assays. Therapeutic enzymes inhibition experiments showed moderate anti-cholinesterase (0.98–1.16 mg galanthamine equivalents/g decoction) and strong anti-tyrosinase (13.6–15.0 mg kojic acid equivalents/g decoction) properties for Stachys herbal teas. ConclusionFindings indicate that the decoction of Stachys species contain important bioactive phenolics and have promising antioxidant effects and health benefits. Thus, these medicinal herbs can be considered as useful ingredients in food and pharmaceutical products.

Neutralization Effect of Tithonia diversifolia (Hemsl.) A. Gray against Bitis arietans and Naja nigricollis venoms-induced toxicity

Leaf methanol extract and fractions of Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) used in traditional medicine was evaluated for neutralization of toxicity induced by Bitis arietans and Naja nigricollis snake venoms in mice and rats. Inhibition of adenosine diphosphate-induced platelet aggregation, antioxidant activity, total phenol content and neutralization of venom-induced toxicity were evaluated by standard methods. The methanol extract was the most active inhibitor of platelet aggregation (66.7 - 84.8%) in the B. arietans model at 100 - 500 μg/ml. The methanol extract and fractions appear to be equipotent in inhibiting platelet aggregation (68 - 74%) induced by N. nigricollis. The aqueous fraction was more active against B. arietans venom at 500 μg/ml as an inhibitor of platelet aggregation (59.4% inhibition), while the dichloromethane (DCM) fraction was more potent against N. nigricollis (70.97% inhibition). The methanol extract showed highest DPPH radical scavenging activity followed by the aqueous and DCM fractions. Total phenolic content was in the order: methanol extract > DCM fraction > aqueous fraction. The aqueous fraction was a better antivenin agent in both B. arietans (complete protection at 24 h) and N. nigricollis-envenomed mice and rat models. Anti-snake venom activity was more prominent at 24 h. The results herein, being the very first report, indicate the potential antiophidic activity of T. diversifolia leaf particularly against B. arietans-induced toxicity.

개박하 추출물의 피부장벽 기능에 대한 효과

Nepeta cataria commonly known as catnip, catswort, catwort, and catmint, is native to Europe, Asia, and America, and has a history of use in traditional medicine for a variety of ailments. Although N. cataria exhibits desirable biological effects, such as anti-microbial, anti-inflammatory, and anti-tumor activities, the effect of N. cataria extract on the skin barrier function remains unknown. Thus, we herein examined the application of functional materials by testing a variety of physiological activities of N. cataria extract. N. cataria extract was found to possess a low cytotoxicity and a high DPPH radical scavenging activity, which resulted in a significant increase in the transactivation activity of PPAR response elements (PPREs) such as peroxisome proliferator-activated receptor (PPAR)-α. Finally, it was found that N. cataria extract promotes the expression of filaggrin and involucrin, which is related to skin barrier protection. These results indicate that N. cataria extract may be an effective comfound for improving the skin barrier function.

Evaluation of antioxidant, antibacterial and wound healing activities of Vitex pinnata.

Background: Vitex pinnata is one of the many plants known for its ethnomedicinal properties. However, the pharmacological properties of this plant have not been well studied. This study aims to determine the antioxidant, antimicrobial and wound healing properties of the methanolic extract of the leaves and the hexane, chloroform and ethyl acetate fractions. Methods: The leaves of Vitex pinnata underwent methanol extraction and the methanol extract was fractionated with hexane, chloroform and ethyl acetate solvents. The antioxidant activity was determined using the DPPH radical scavenging assay. The antimicrobial activity was assessed by disc diffusion assay against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. For the wound healing studies, the methanolic extracts of V. pinnata were used to prepare ointments with compositions of 10% (w/w) and 50% (w/w), which were evaluated for wound healing activity in an excision wound model in Wistar rats. Results: All the extracts showed antioxidant activities, with the ethyl acetate extract having the highest DPPH radical scavenging activity, followed by the methanol, chloroform and hexane extracts. Similarly, their quercetin equivalent concentrations were 33.1, 31, 20.3 and 4.5 mg/mL, respectively. Except for the methanol extract, the disc diffusion assay showed that the extracts demonstrated species-specific antibacterial activities, with the ethyl acetate extract showing antibacterial activities against all four tested strains. The wound healing activity of the high dose treated group (50% [w/w]) shows significant increase of wound contraction when compared to the control group. Conclusion: In the current study, the ethyl acetate extract showed activity for all tested bacteria and also had the highest DPPH activity. The methanolic extracts of V. pinnata leaves show modest wound healing activity in an excision wound model.

Bioactive compounds from Syzygium malaccense leaves: optimization of the extraction process, biological and chemical characterization

Syzygium malaccense belongs to the family Myrtaceae and it is popularly recognised as ‘jambo’ in Brazil. It is poorly studied regarding the bioactive compounds of fruits and leaves. This study aimed at optimizing the extraction and characterization of bioactives compounds from S. malaccense leaves. Extraction was optimized using a 23 full factorial design to evaluate the effect of ethanol concentration, time and temperature on polyphenols and antioxidants contents. Analyses of phenolic compounds content (Folin-Ciocalteau and HPLC-DAD), in vitro antioxidant capacities (DPPH, ABTS and FRAP), antimicrobial activity against bacteria and yeasts of ethanolic extract was carried out in optimal conditions of extraction. The optimized extraction condition was 45 min., 80°C and 40:60 (v v-1) ethanol:water. The extract showed high total phenolic content (0.074 mg GAE kg-1), DPPH (0.666 μmol TE kg-1) and ABTS (0.853 μmol TE kg-1) free radical scavenging ability and appreciable ferric reducing power (1.267 μmol Fe2+ kg-1). HPLC methodology allowed the identification of four bioactive compounds: gallic acid (0.00036 mg kg-1), catechin (0.00021 mg kg-1), rutin (0.00027 mg kg-1) and quercetin (0.00003 mg kg-1). The extract showed inhibitory activity against S. aureus (1 µg L-1); S. bongori (8 µg L-1), C. albicans and C. tropicalis (2 µg L-1). It also showed microbicidal potential against S. aureus; C. albicans and C. tropicalis.

Effects of encapsulated green coffee extract and canola oil on liquid kashk quality

In this study, we used a water-in-oil (W/O) emulsion encapsulation technique to enhance green coffee extract in the novel kashk product and protect it against hot filling. Green coffee extracts (GCE) in free (1%, 0.5%, and 0.25%) and encapsulated form (EGCE) (5%, 2.5%, and 1.25%) were added to kashk during hot filling, and their physicochemical and sensory properties were investigated. The EGCE kashk had higher oxidative stability (0.43 h) than the control due to the extract’s high phenolic content and DPPH radical scavenging activity (74%). Although a high concentration of GCE caused a higher pH (4.02), the latter declined in all the samples during the storage period. Further, the size of droplets in the emulsion varied from 3.20 to 8.51 μm, confirming the well-encapsulated GCE by Fourier transform infrared. In addition, palmitic acid and oleic acid were detected in GCE by gas chromatography as the main saturated and unsaturated fatty acids, respectively. All the treatments had similar rheological properties and the highest flow index was observed in the samples with EGCE 5% on day 60. The sensory evaluation showed that the assessors preferred the kashk formulated with 1% GCE. Finally, GCE encapsulation protected the color of the samples, and the b* value remained unchanged, whereas the lightness (L*) increased. We suggest that a W/O emulsion is a successful technique for GCE encapsulation in kashk and can offer the latter to consumers as an alternative type of flavored dairy product with a better shelf life and health benefits.

Properties and application of bilayer films based on poly (lactic acid) and fish gelatin containing epigallocatechin gallate fabricated by thermo-compression molding

An alternative approach towards production of active bilayer films based on poly (lactic acid) (PLA) and fish gelatin incorporated with epigallocatechin gallate (EGCG) fabricated by thermo-compression molding was investigated. This strategy permitted the reduction of production times and avoided the uses of inorganic solvents. Thermo-compression molded bilayer films showed good handling, transparency and low water vapor permeability. The incorporation of EGCG promoted interactions with gelatin, as shown by Fourier transform infrared spectroscopy. These interactions contributed to homogeneous structures, as observed by scanning electron microscopy. Bilayer films with 12 wt % EGCG showed good mechanical properties, high water and UV–visible light barrier properties as well as a high DPPH radical scavenging activity. These bilayer films were used to produce bags, in which striped catfish slices (SCS) were packaged. After 7 days of storage at 4 °C, SCS packaged in bags prepared with12 wt % EGCG had lower psychrophilic bacteria count, weight loss, peroxide value, and thiobarbituric acid reactive substances (TBARS) value along with higher docosahexaenoic acid (C22:6 n-3) content than those packaged in bags prepared without EGCG or in LLDPE bags. No difference in overall likeness score was found among all the samples packaged in different bags after 7 days of storage. Therefore, PLA/gelatin bilayer films containing 12 wt % EGCG possessed satisfactory film properties with augmented antioxidant activity, and thus they could be used as active food packaging, especially for fish slices with high lipid content.

Evaluation of Antidiabetic Activities of Casein Hydrolysates by a Bacillus Metalloendopeptidase

Enzymatic hydrolysis is commonly used to produce bioactive peptides from protein such as casein that is rich in bioactive peptide sequences. In this study, a Bacillus metalloendopeptidase (PROTIN SD-NY10) was used to hydrolyze casein to produce bioactive peptides with antidiabetic and antioxidant activities. Several factors affecting the hydrolysis were assessed such as hydrolysis time, metalloendopeptidase concentration, casein concentration, pH, and temperature. The results showed that casein could be effectively hydrolyzed by the metalloendopeptidase, and the casein hydrolysates were shown with high inhibitory activities on α-glucosidase and α-amylase, as well as high antioxidant activity. The high inhibitory activities on α-glucosidase (68.5–80.55%) and α-amylase (74.10–77.15%) were obtained under the selected hydrolysis conditions (pH 7.5, 40 °C, 1% metalloendopeptidase, 10% casein, and 3 h). Meanwhile, the high DPPH radical scavenging activity (55.02–69.40%) could also be obtained under the same hydrolysis conditions. Therefore, the casein hydrolysate obtained by hydrolysis with a metalloendopeptidase of this study could be explored as a bioactive agent for potential application in functional products.

Health promoting pigments and bioactive compounds of six vegetables grown in Bangladesh

Increasing of chronic diseases due to low consumption of vegetables considered one of the crucial challenges to human being in current circumstance. Adequate intake of vegetables only the possible solution from get rid of the problem. So it is indispensible to determine food value present in vegetables which were the core objective of our present study. Among the tested vegetables beetroot showed the highest nitrate content (874 mg Kg-1) whereas the lowest nitrate content was found in bitter gourd (56 mg Kg-1). Total chlorophyll content was in cucumber, bitter gourd, beetroot, tomato and brinjal was 10 5.89, 4, 0.80 and 0.78 mg 100g-1, respectively. The highest carotene contain was found in cucumber (1.63 mg100g-1). Beetroot, tomato, brinjal and bitter gourd showed reduction in carotene content at 61.96, 71.16, 87.73 and 97.71%, respectively in response to cucumber. Lycopene content was the highest in beetroot (3.46 mg 100g-1) and the lowest in brinjal (0.115 mg 100g-1). All the tested vegetables contained abundance vitamin C (ranges from85.71 to 17.14 mg 100g-1). DPPH radical scavenging activity was present in all tested vegetables in which beetroot exhibited the highest DPPH radical scavenging activity with an IC50 value of 1.17 μgml-1.
 Asian J. Med. Biol. Res. June 2019, 5(4): 280-285

Effect of Extraction Solvents on Total Phenolic Contents and in vitro Antioxidant Activity of the Leaves of Lippia adoensis var. Koseret Sebsebe

Lippia. adoensis var. koseret is an endemic herb to Ethiopia and is traditionally used as food flavoring and traditional medicine. This paper reported the total phenolic and flavonoid contents, and in vitro antioxidant activity of various extracts from the dried leaf of this herb. Aqueous: methanol (20:80, v/v) extract contained highest amount of total phenolic (67.61 ± 9.89 mg of gallic acid equivalent/g). Total flavonoid contents were highest in acetone extract (25.24 ± 0.43 mg of quercetin equivalent/g). An increase in the extracted concentration resulted in an increase of antioxidant power for all the extracts. The aqueous: methanol (20:80, v/v) extract showed highest DPPH radical scavenging (IC 50 = 10.96 ± 0.42 mg/ml) iron reducing power (IC 50 = 123.97 ± 3.23 mg/ml), total antioxidant activity (105.32 ± 10.67 mg ascorbic acid equivalent/g), and iron chelating activity (IC 50 = 81.31 ± 15.94 mg/ml) than other four solvents used. Total phenolics well correlated with DPPH (R 2 = 0.88, p < 0.05) and Ferric reducing power (R 2 = 0.77 p < 0.05). Whereas, total flavonoid content well correlated with total antioxidant (R 2 = 0.73 p < 0.05). The study showed the antioxidants activities of the crude extract were variable when extracted by different solvents indicating a high potential to be used as natural antioxidants in preventing various oxidative stresses and as food preservatives. Keywords: Antioxidant; α- Amylase; Phenolic compounds; Herbs; Lippia adoensis var . koseret DOI: 10.7176/FSQM/94-04 Publication date: February 29 th 2020

Chemical characterization of the species Raphanus sativus L. under different conditions of fertilization and water stress conditions

This study quantifies phenolic and flavonoid compounds and evaluates the antioxidant activity by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, also identifying some secondary metabolites of R. sativus under organic fertilization and water stress. For this, a greenhouse experiment was carried out with the preparation of plant extracts (leaves and roots), quantification of phenolic and flavonoid compounds, analysis of antioxidant activity, and phytochemical screening. Different classes of secondary metabolites (catechins, steroids, saponins, among others) were identified. The DPPH method showed that the leaf extract has higher DPPH radical scavenging activity. The leaf extract had a high content of phenolic compounds, especially in treatments without water stress, either with organic fertilization (1925.59 mg GAE/g extract) or with mineral fertilization (2058.47 mg GAE/g extract). For root extracts, R. sativus developed under water stress and organic fertilization showed higher phenolic content (1383.24 mg GAE/g extract). Regarding flavonoid content, the root extract that showed the highest concentration corresponded to the treatment under water stress and without fertilization (82.1 mg QE/g extract). Therefore, radish was shown to be rich in bioactive compounds and with antioxidant potential in both its leaves and roots.

Brazilian native species as potential new sources of natural antioxidant and antimicrobial agents

The antioxidant and antimicrobial activities of extracts of 12 plant species growing in Brazil were determined. Antimicrobial activity against 12 food-related bacterial species was studied using the disc-diffusion, MIC, and MBC methods. Campomanesia eugenioides extract was the most active against the tested Gram-positive bacteria, whereas Parapiptadenia rigida bark extract presented the highest activity against the evaluated Gram-negative bacteria (MIC and MBC of 0.075 and 0.62 mg ml−1, respectively, against Pseudomonas aeruginosa). Those two extracts also presented high phenolic content and high DPPH and ABTS radical scavenging ability. C. eugenioides extract presented high Fe2+ chelating capacity. The results of the present study demonstrate that, among the evaluated extracts, P. rigida bark and C. eugenioides, both Brazilian native species, presented the highest potential of application as natural antimicrobial and antioxidant agents.

Development of fermented surimi products using simulated tofuyo processing: associated changes in chemical composition, antioxidant activities and angiotensin-converting enzyme inhibition

Traditional Japanese koji-fermented tofu (tofuyo) processing was simulated to make fermented seafood. The koji fermentation process at room temperature was applied to steamed surimi and kamaboko to develop new types of food, extend their shelf life and improve their health-promoting effects. Extractive nitrogen and sugar contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, copper-reducing activities, and angiotensin-converting enzyme (ACE) inhibitory activity significantly increased after fermentation. These increases were the highest in kamaboko. Kamaboko fermented for 6 months had the highest DPPH radical scavenging, copper-reducing activities, and ACE inhibition. Kamaboko fermented for 6 months showed statistically the same copper-reducing power and ACE inhibition to tofuyo, but significantly higher DPPH radical scavenging activity. Size-exclusion chromatography showed the same peak(s) analyzed as Lowry-reactive substances, ninhydrin-reactive substances, sugar, and DPPH radical scavenging activity. The most antioxidative fraction had a molecular weight of 900–1300 and a sugar and amino acid structure(s). There was no specific ACE inhibitory fraction(s). The koji fermentation process at room temperature did not need additional energy, led to different foods with a sweet and a umami-rich taste and a soft texture. Additionally, koji fermented steamed surimi and kamaboko effectively prolonged best-before periods of up to 6 months.

Antifungal effect of Lamiaceae herb water extracts against Fusarium root rot in Asparagus

In the current study, the antioxidative and in vitro antifungal properties of ten Lamiaceae herbs were estimated. Based on the results, the in vivo antifungal potential of oregano, sage, hyssop and lemon balm water extracts against Fusarium root rot in asparagus plants was evaluated. Water extracts of several herbs (0.5% and 2%, w/v) showed high DPPH radical scavenging activity, and oregano, sage and lemon balm extracts exhibited considerable suppression of Fusarium oxysporum f. sp. asparagi (Foa) in vitro. Regarding in vivo evaluation, asparagus plants treated with water extracts (20%, w/v) of the selected four herbs were inoculated with Foa. Four weeks after Foa inoculation, lower disease incidence and indices were observed in all the extract-treated plants compared to control. These effects could be attributed to reduced Fusarium population owing to fungistasis induced by the extracts in the rhizospheric soil. Consequently, dry weights of shoots and roots treated with herb extracts were observed to be higher than those in control. Evaluation of caffeic acid and rosmarinic acid as the possible antifungal properties present in the Lamiaceae herbs also showed a suppressive effect on Fusarium population in the in vitro analysis. From these findings, it can be concluded that water extracts of the selected four herbs have high antioxidative properties and antifungal potential against Fusarium oxysporum f. sp. asparagi. In this case, the presence of possible antifungal secondary metabolites such as caffeic and rosmarinic acid in the extracts could be related to this antifungal potential.

Low-density lipoprotein-antioxidant flavonoids and a phenolic ester from Plectranthus hadiensis var. tomentosus

To investigate the effects of extraction solvents and drying methods on Plectranthus hadiensis var. tomentosus quality, eight compounds were isolated and the content of active compounds with their antioxidant activities were compared. Compounds 1 and 2 were known antioxidants, whereas the low-density lipoprotein (LDL)-antioxidant activities of compounds 3, 5, 6, and 7 are reported for the first time, with IC50 values of 2.5, 3.8, 22.8, and 53.7 μM, respectively. Our analysis of 30‒95% ethanol extracts from freeze- and air-dried leaves and stems revealed a relationship between extract composition and antioxidant activity. The 95% ethanol extracts of freeze-dried stems (FDS) exhibited highest phenolic and flavonoid content, which were 1.40 and 2.67 times, respectively, greater than those of air-dried stems (ADS), and very high LDL-antioxidant and DPPH radical scavenging activities, which may have resulted from the phenolic ester rosmarinic acid (2), a major component of FDS extracts and potent antioxidant. In contrast, the 95% ethanol extracts of ADS exhibited relatively low antioxidant activity, possibly owing to the low antioxidant activity of the main components ayanin (7) and (+)-plectranthone (8). These results are important for the development of P. hadiensis var. tomentosus as an effective natural antioxidant material.

Protein degradation and peptide formation with antioxidant activity in pork protein extracts inoculated with Lactobacillus plantarum and Staphylococcus simulans

This study focused on sarcoplasmic and myofibrillar protein degradation and the formation of peptides with antioxidant activity by mixed starters (Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201). Gel electrophoresis indicated that the mixed starters can hydrolyze both sarcoplasmic and myofibrillar proteins, and the concentration of peptides increased (P < .05). Compared with the control group, using mixed starters led to a significant increase (P < .05) in the DPPH radical scavenging activity, Fe2+ chelating activity, and ABTS radical scavenging activity of sarcoplasmic proteins, but demonstrated no significant difference in myofibrillar proteins. Two hydrophobic fractions (C2, C5) separated by RP-HPLC in the inoculation groups with sarcoplasmic proteins showed high DPPH radical scavenging activity (66.60%, 60.50%). Eighteen peptides were identified by LC-MS/MS, which mainly arose from triosephosphate isomerase, creatine kinase M-type, and glyceraldehyde-3-phosphate dehydrogenase. Hydrophobic amino acids accounted for a large proportion. Our results indicate that mixed starters affect proteolytic characterization and contribute to the formation of peptides with antioxidant capacity in sarcoplasmic proteins.

Isolation of crude fucoidan from Sargassum wightii using conventional and ultra-sonication extraction methods

Fucoidan, a fucose rich sulphated polysaccharide, generally found in cell wall matrix of brown seaweeds possess diverse physiological properties. Crude fucoidan was extracted from Sargassum wightii, a brown seaweed common along the Indian coastline. A comparison was made between hot water extraction (HWE) and ultra-sonication extraction (UAE) methods. The UAE method gave higher yield (14.61 g/100 g) than HWE method (10.59 g/100 g). The UAE fucoidan had lighter colour than HWE, as indicated by Hunter colour values. The water activity values for fucoidans obtained were 0.14 for HWE and 0.19 for UAE. The sulphate content was similar in both fucoidans (̴17%). However, HWE fucoidan had higher content of fucose. The Fourier transform infrared spectroscopy spectra confirmed the presence of sulphate groups in both the fucoidans. The absorption bands at 1245.37 cm−1 and 1294.99 cm−1 in the HWE and UAE fucoidan respectively, indicated the S–O stretching due to sulphate groups in the fucose monomer. The thermal transition temperature as obtained by differential scanning calorimetry for HWE (127.3 °C) was lower than UAE fucoidan (131.8 °C). HWE fucoidan had higher DPPH radical scavenging and reducing power than UAE fucoidan. On the other hand, UAE fucoidan had higher metal chelating activity. The present study demonstrated that ultra-sonication can be an effective alternative for the extraction of sulphated polysaccharide from seaweed, in term of higher yield. The health benefits of Sargassum wightii and fucoidan obtained from it, could be explored by incorporation in different food systems.

In situ synthesis of multi-functional gelatin/resorcinol/silver nanoparticles composite films

Abstract Silver nanoparticles (AgNP) were synthesized in situ by reducing AgNO3 using resorcinol and gelatin to prepare functional gelatin/resorcinol/AgNP nanocomposite films (Gel/Res/AgNP). The nanocomposite film exhibited a characteristic light absorption peak of AgNP at 420 nm and improved UV-light barrier property. X-ray diffraction (XRD) results also showed a characteristic reflection peak of crystalline AgNP around 2θ = 38° corresponding to the (111) diffraction plane of AgNP. The water vapor permeability (WVP), water contact angle (WCA), surface morphology and thermal stability of the composite films were not affected, but the tensile strength (TS) of the composite film decreased and the elongation at break (E) increased by the formation of AgNP. The Gel/Res/AgNP nanocomposite film showed a strong antioxidant property with high DPPH and ABTS free radical scavenging activity. Also, the Gel/Res/AgNP nanocomposite films exhibited strong antimicrobial activity against foodborne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. The developed Gel/Res/AgNP composite films with potent antimicrobial and antioxidant activities have a high potential to be used in food packaging to increase the shelf life of packaged food.

The cytotoxicity and antioxidant activity analysis of the isolated constituents and extracts from endemic Centaurea derderiifolia

It is aimed to investigate the cytotoxic effects of the various extracts from the leaf and seed of Centaurea derderiifolia on the growth human cervical adenocarcinoma (HeLa) cells by xCELLigence method and to isolate the cytotoxic constituents. The results showed that subfractions 2 and 3 exhibited remarkable inhibitory effect against HeLa (IC50 < 10 µg/mL). The chloroform extract of leaf displayed the highest cytotoxic effect on HeLa cells (IC50 < 50 µg/mL) and was therefore subjected to a bioassay-guided multistep separation procedure. The pure compounds were elucidated by spectroscopic and mass-spectrometric analyses, including 1 D-, 2 D-NMR. In addition to cytotoxic effects of the isolated constituents, their antioxidant activities were also studied. On the other hand, subfraction 4 exhibited the highest DPPH radical scavenging activity (IC50 = 0.76 ± 0.03 mg/mL). β-sitosterol-3-O-β-d-glucopyranoside was isolated for the first time from this plant and three compounds from the bioactive subfractions were identified.