Functionalized silver nanoparticles synthesized from marine algae: In vitro Evaluation of Antibacterial Potential

2021 ◽  
Vol 16 (8) ◽  
pp. 38-49
Author(s):  
Siva Kumar Kandula ◽  
Satyanarayana Swamy Cheekatla ◽  
Venkata Satya Mahesh Kumar Metta ◽  
Venkata Rajagopal Saladi

Natural antioxidants, in particular phenolic derivatives, are used efficiently to combat against oxidative induced tissue damages. The objective of the study is to determine the antioxidant potential of methanolic extracts obtained from eight marine algal species (Enteromorpha compressa, Chaetomorpha antennina, Caulerpa racemosa, Caulerpa taxifolia, Sargassum vulgare, Padina tetrastromatica, Amphiroa fragilissima and Gracilaria corticata) by assessing their total phenolic content, DPPH scavenging assay, FRAP assay, H2O2 radical and superoxide radical scavenging activities. Among them, P.tetrastromatica, S.vulgare, E.compressa, C.taxifolia display significant antioxidant activities. Further, the aqueous extracts of these four algae are used for bioreduction of silver nitrate to silver nanoparticles (AgNPs) by green synthesis method at room temperature. UV-Visible spectrum revealed the surface plasmon resonance at 430 and 440nm. The characterizations of AgNPs by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies revealed the bioreduction and capping of AgNPs. XRD analysis elucidated the synthesized nanoparticles having face centered cubic crystalline geometry, with a mean size of 17 nm. The nanoparticles have better antimicrobial activity against cocci shaped than the rod shaped bacteria. The minimum inhibitory concentration and minimum bactericidal concentration exhibit more activity against S.aureus and B.cereus rather than E.coli.

2018 ◽  
Vol 43 (3) ◽  
pp. 19
Author(s):  
Juliana Metzner Franco ◽  
Silvana Marina Piccoli Pugine ◽  
Antônio Márcio Scatoline ◽  
Mariza Pires De Melo

The aim of the present study was to evaluate in vitro antioxidant capacity of Melissa extract (ME) (Melissa officinalis L.) and its protective effect on peroxyl radical-induced oxidative damage in erythrocytes. ME used in present study was obtained by rota-evaporation of the crude extract (ethanol:water/dried leaves). Total phenolic and flavonoids contend determination, 176.8 ± 13.2 mg GAE/g dw and  26.2 ± 3.2 mg QE/g dw, respectively).  Total equivalent antioxidant activities, TEAC in mg TE/g dw, were 61.4 ± 5.5 and 512.4 ± 77.2 for respective FRAP assay and DPPH• radical-scavenging. The ME acts as an antioxidant on NO and O2•-, when ME exerted a higher antioxidant action on NO scavenging to compared to the ascorbic acid (1.9 times), however, the antioxidant capacity of ME on O2•- was lower than ascorbic acid (5.6 times). The values of hemolysis inhibition from ME (IC50, 2.0 ± 0.5 mg/mL) were higher than ascorbic acid (IC50, 7.1 ± 1.8 mg/mL). Extract of Melissa was able to eliminate biological free radicals, suggesting a potential to prevent oxidative damage in vivo. In fact, the ME exerted protective action on cell membrane lysis in situ.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wissal Kchaou ◽  
Fatma Abbès ◽  
Hamadi Attia ◽  
Souhail Besbes

Second-grade dates (Phoenix dactyliferaL.), with hard texture, from three selected Tunisian cultivars (Allig, Deglet Nour, and Bejo) were analysed from their antioxidant activities using DPPH radical scavenging activity, FRAP assay, H2O2scavenging activity, and metal chelating activity. Date extracts showed strong and concentration-dependant activity in all tested methods. The results showed that the best antioxidant activity was obtained in Allig, followed by Bejo and Deglet Nour. Total phenolics, total flavonoids, carotenoids, and tannins were determined spectrophotometrically in three date extracts. Results indicated that date contained significantly different amounts of these compounds. In fact, Allig presented the highest antioxidant compounds, followed by Bejo and Deglet Nour. Correlation analyses indicated a positive linear relationship between antioxidant activities and total phenolic and flavonoid content of date. This study demonstrates the potential antioxidant activity with Tunisian date, where we can use these natural extracts as food additives in replacement of synthetic compounds.


2020 ◽  
Vol 3 (1) ◽  
pp. 47
Author(s):  
Nadezhda Petkova ◽  
Manol Ognyanov ◽  
Blaga Inyutin ◽  
Petar Zhelev ◽  
Panteley Denev

Crab apple (Malus baccata (L.) Borkh.) was mainly distributed in Europe as an ornamental plant, but the nutritional properties of its edible fruits were not fully revealed. The aim of the current study was to characterize the phytochemical composition of ripen carb apple fruits and to evaluate their nutritional and antioxidant potentials. The fruits were assayed for moisture and ash content, proteins, lipids, carbohydrates, titratable acidity (TA), pH, total phenolic compounds and natural pigments. Among the analyzed carbohydrates cellulose was found in the highest content (6% dw), followed by sugars (sucrose, glucose and fructose) and 1.8 % dw uronic acids. The total chlorophylls and carotenoids contents in their fruits were 6.51 and 4.80 μg/g fw, respectively. Total monomeric anthocyanins were not detected. The highest content of total phenolic compounds (2.67 mg GAE/g fw) was found in 95 % ethanol extract from fruits, while the total flavonoids were relatively low – 0.1 mg QE/g fw. DPPH assay (17.27 mM TE/g fw) and FRAP assay (14.34 mM TE/g fw) demonstrated in vitro antioxidant activities of crabapple. Malus baccata fruits were evaluated as a rich source of dietary fibers and phenolic compounds with significant antioxidant potential that could be used in human nutrition.


Author(s):  
Larissa Irene Da Silva ◽  
Arunachalam Karuppusamy ◽  
Fabio Miyajima ◽  
Ivana Maria Povoa Violante ◽  
Isanete Geraldini Costa Bieski ◽  
...  

Objective: The purpose of this study was to evaluate selected Brazilian plants from Juruena valley region of Mato Grosso, for their in vitro antimicrobial and antioxidant activities.Methods: The powder obtained from different parts of the twenty-six (26) plants were macerated in hydroethanolic solution to obtain the extracts. The hydroethanolic extracts were tested for their in vitro antimicrobial activity by determining the MIC using broth microdilution. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical, ferric reducing antioxidant power (FRAP) and nitric oxide (NO) methods were used for the determination of antioxidant activities. Correlation between classes of secondary metabolites and antioxidant activity was assessed.Results: Phanera glabra extract (HEPg) showed broad antibacterial spectrum, presenting the best activity against Klebsiella pneumoniae. Hevea microphylla extract (HEHm) presented a narrow spectrum of antibacterial activity with strong effect against Shigella flexneri. The only plant with broad spectrum antifungal activity was Bertholletia excelsa (HEBe), with moderate activity against strains of Aspergillus and Candida. The following extracts were prominent regarding their activities in the DPPH and FRAP assays-HEBe, Cariniana rubra (HECr) and in the FRAP assay alone, Cedrela odorata (HECo) and HEPg. None of the extracts was active in the NO assay. A significant association was observed between DPPH activity and the total phenolic contents.Conclusion: Our results justified the use of some of the investigated plants in the Brazilian ethnomedicine. The antibacterial activities of these plants are bacteriostatic in nature. These findings support that a number of investigated plants could be a valuable source of new antioxidant and antimicrobial compounds that can potentially deliver novel mechanisms of actions.However, further studies are required.


2009 ◽  
Vol 6 (2) ◽  
pp. 227-231 ◽  
Author(s):  
S. A. Adesegun ◽  
A. Fajana ◽  
C. I. Orabueze ◽  
H. A. B. Coker

The antioxidant activities of crude extract ofPhaulopsis fascisepalaleaf were evaluated and compared with α-tocopherol and BHT as synthetic antioxidants and ascorbic acid as natural-based antioxidant.In vitro, we studied its antioxidative activities, radical-scavenging effects, Fe2+-chelating ability and reducing power. The total phenolic content was determined and expressed in gallic acid equivalent. The extract showed variable activities in all of thesein vitrotests. The antioxidant effect ofP. fascisepalawas strongly dose dependent, increased with increasing leaf extract dose and then leveled off with further increase in extract dose. Compared to other antioxidants used in the study, α-Tocopherol, ascorbic acid and BHT,P. fascisepalaleaf extract showed less scavenging effect on α,α,-diphenyl-β-picrylhydrazyl (DPPH) radical and less reducing power on Fe3+/ferricyanide complex but better Fe2+-chelating ability. These results revealed thein vitroantioxidant activity ofP.fascisepala.Further investigations are necessary to verify these activitiesin vivo.


2018 ◽  
Vol 4 (3) ◽  
pp. 114-119
Author(s):  
Quang Ung Le ◽  
◽  
Horng Liang Lay ◽  
Ming Chang Wu ◽  
◽  
...  

Agrimonia pilosa Ledeb (AL) has received considerable attention as a herbal medicine for its applications in ethnopharmacology with heath benefits. This study aimed to investigate antioxidant activities and A549 growth inhibitory capacity from its root extract (RE) and aerial parts extract (AE). The 50% ethanol extracts were used for the tests. The total polyphenol content and the antioxidant effects comprising ABTS+ and DPPH free radical scavenging activities were evaluated. Phenolic compounds in the extracts were isolated using high performance liquid chromatography (HPLC). Lactate dehydrogenase released in medium was also evaluated. Total phenolic and flavonoid content, and in vitro antioxidant potential of the RE were higher (p<0.01) than that of the AE. Two individual phenolic compounds consisting of 4-hydroxybenzoic acid and p-coumaric acid were firstly identified in both by HPLC. The RE exhibited higher A549 inhibitory capacity compared to the AE and activated the apoptotic proteins of bcl-2, bax, bad, caspase-3 and caspase-9 in A549. In conclusion, the AL extracts were more effective in antioxidant and A549 cells inhibitory capacity.


2016 ◽  
Vol 11 (9) ◽  
pp. 1934578X1601100
Author(s):  
Pei-Ling Yen ◽  
Sen-Sung Cheng ◽  
Chia-Cheng Wei ◽  
Huan-You Lin ◽  
Vivian Hsiu-Chuan Liao ◽  
...  

The in vitro and in vivo antioxidant activities and its potential to protect against amyloid-β toxicity of essential oils from Zelkova serrata (Thunb.) Makino were investigated in the model organism Caenorhabditis elegans. The results revealed that the essential oil of Z. serrata heartwood exhibited great radical scavenging activities and high total phenolic content. In vivo assays showed significant inhibition of oxidative damage in wild-type C. elegans under juglone-induced oxidative stress and heat shock. Based on results from both in vitro and in vivo assays, the major compound in essential oil of heartwood, (-)-(1 S, 4 S)-7-hydroxycalamenene (1 S, 4 S-7HC), may contribute significantly to the observed antioxidant activity. Further evidence showed that 1 S, 4 S-7HC significantly delayed the paralysis phenotype in amyloid beta-expressing transgenic C. elegans. These findings suggest that 1 S, 4 S-7HC from the essential oil of Z. serrata heartwood has potential as a source for antioxidant or Alzheimer's disease treatment.


2020 ◽  
Vol 44 (1) ◽  
pp. 33-41
Author(s):  
Md Nazim Uddin ◽  
Subrata Chandra Roy ◽  
Abdulla All Mamun ◽  
Kanika Mitra ◽  
Md Zahurul Haque ◽  
...  

The phytochemicals (total phenolic, tannin, flavonoid, alkaloid, and saponin) contents in the Aloe vera gel derived from the leaf of Aloe vera (L.) Burm. f. (Synonym Aloe barbadensismiller) were extracted and their antioxidant capacity was studied by Ferric reducing antioxidant power assay (FRAP), by free radical-scavenging capability using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Three different solvents with three different polarities CH3OH, CH3OH: HCl, CH3CH3OH: H2O were used at v/v ratio of 100, 98:2, 70:30, respectively. The acidified methanol solvent extracted the highest amounts of phytochemicals including total phenolic (4.64 mg gallic acid equivalent/g), tannin (3.84 mg tannic acid equivalent/g), alkaloid (662 mg piperine equivalent/g), and saponin (353 mg diosgenin equivalents/g) compared to the other two solvents. Similarly, in the extract with acidified methanol solvent, high level of total antioxidant activity (about 12 mg gallic acid equivalent/g) and scavenging effects expressed as 50% inhibition concentrations (IC50) for DPPH and ABTS assay were determined to be about 61 μg/mL and 371 μg/mL, respectively, which are higher than those with the other two solvents. The gel extract could be used as a potent antioxidant in medicine and food industries. Journal of Bangladesh Academy of Sciences, Vol. 44, No. 1, 33-41, 2020


2011 ◽  
Vol 76 (11) ◽  
pp. 1485-1496 ◽  
Author(s):  
Wei Su ◽  
Peiyuan Li ◽  
Lini Huo ◽  
Caiying Wu ◽  
Nana Guo ◽  
...  

Various solvent extracts of Phymatopteris hastata, a traditional Chinese medicinal material, were screened for their antioxidant activities. Four systems of in vitro testing were employed to investigate the antiradical and antioxidant effect, i.e., the 2,2-diphenyl-1-picryhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) systems, the hydroxyl radical scavenging assay and the reducing power. In addition, butylated hydroxytoluene (BHT), a widely used synthetic antioxidant, was also studied for comparison. The results revealed that the ethyl acetate extract exhibited outstanding antioxidant activities, which was close or even superior to BHT. Furthermore, the total phenolic (TP) and total flavonoid (TF) contents of different extracts were measured, expressed as gallic acid and rutin equivalent, respectively. The antioxidant activities and the TP/TF content of different extracts followed the same order: ethyl acetate extract > butyl alcohol extract > petroleum ether extract, showing a good correlation between the antioxidant activities and the TP/TF content. The results showed that these extracts, especially the ethyl acetate extract, were rich in phenolics and flavonoids and could be considered as natural antioxidants.


Author(s):  
SURACHAI TECHAOEI ◽  
KHEMJIRA JARMKOM ◽  
THISAKORN DUMRONGPHUTTIDACHA ◽  
WARACHATE KHOBJAI

Objective: This research is to study the production of natural red pigment by Monascus purpureus TISTR3615 in the submerged and solid-statefermentation system using Pathumthani-1 rice as a carbon source.Methods: The antioxidant activity of the red pigment was evaluated in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS radical scavenging assay,and ferric-reducing antioxidant power (FRAP) assay, including total phenolic compound.Results and Discussion: The maximum of red pigment production was 0.55±0.02/ml (OD 680 nm) after incubation at 30°C for 24 days. Theantioxidant activity based on inhibition DPPH (%), ABTS radical scavenging activity (%), and FRAP activity (mM Fe2+/g) was 97.80±1.51,68.64±0.46, and 0.32±0.021, respectively. The total phenolic content was 164.78±2.82 μg GAE/mg.Conclusion: It was estimated that Monascus pigments, leading to nutraceutical and pharmaceutical applications, cosmetic industry, and foodindustry.


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