scholarly journals Relationships between Structure and Antioxidant Capacity and Activity of Glycosylated Flavonols

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 849
Author(s):  
Zhengcao Xiao ◽  
Liangliang He ◽  
Xiaohui Hou ◽  
Jianping Wei ◽  
Xiaoyu Ma ◽  
...  

The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC under most conditions due to substitution of the 3-position hydroxyl group and glycoside disruption in the molecular planarity. The 7-glycosylated derivatives did not have the above effects, thus generally exhibited ACs similar to their aglycones. Glycosylation decreased the AA of kaempferol and isorhamnetin for both assays in methanol, 3-glycosylation inhibited quercetin AA in the ABTS assay. In the DPPH assay, the AA of 3-glycosylated quercetin was significantly higher than quercetin. Using LC–MS/MS analysis, we found that quercetin and quercetin-7-glucoside underwent dimerization during the antioxidant reaction, potentially leading to a decline in AAs. However, 3-glycoside substitution may have hindered dimer formation, thereby allowing the FLVs to retain strong free radical scavenging abilities.

2018 ◽  
Vol 16 (3) ◽  
pp. 297 ◽  
Author(s):  
Wiwit Denny Fitriana ◽  
Taslim Ersam ◽  
Kuniyoshi Shimizu ◽  
Sri Fatmawati

Moringa oleifera have been evaluated for its antioxidant activity. M. oleifera leaves were extracted with methanol, ethyl acetate, dichloromethane and n-hexane. The antioxidant activity of extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay and an improved 2,2’-azino-bis-[3-ethylbenzothiazoline sulphonate] (ABTS) radical cation decolorization assay in vitro. Trolox was used as standard with IC50 5.89 μg/mL in DPPH assay and 3.06 μg/mL in ABTS assay. The methanol extract showed the highest free radical scavenging activity with IC50 value of 49.30 μg/mL in DPPH assay and 11.73 μg/mL in ABTS assay. This study provided that M. oleifera leaves possess antioxidant.


Author(s):  
ABDELFATTAH EL MOUSSAOUI ◽  
FATIMA ZAHRA JAWHARI ◽  
DALILA BOUSTA ◽  
AMINA BARI

Objective: In this study, we were interested in qualitative, quantitative phytochemical characterization and evaluation of the antioxidant capacity of the total extracts of a plant from northern Morocco, the species selected for this study is Withania frutescens. Materials and Methods: Analysis of mineral elements by inductive coupling plasma-atomic absorption spectroscopy (ICP-AES), phytochemical screening, polyphenol and tannin assays, evaluation of antioxidant activity by the 1,2-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method and reducing power. Results: The plant contains alkaloids, saponins, tannins, mucilages, and coumarins. It has a relatively high content of total polyphenols and tannins of 19.53±0.018 μg genetic generalized epilepsy/mg MS and 6.258±0.062 μg Eqcat/mg MS, respectively. The analysis of mineral elements by ICP-AES shows that our species is rich in mineral elements which are calcium, magnesium, and sodium, and it is devoid of metallic elements such as nickel, lead, cadmium, and cobalt. The evaluation of antioxidant activity by the DPPH free radical scavenging method shows that the half maximal inhibitory concentration of the tested extracts has an antiradical activity of about 0.056±0.008 μg/ml for the ethanol extract and 0.213±0.004 μg/ml for the methanol extract compared to the butylated hydroxytoluene value of 0.009±0.0004 μg/ml which was used as a reference. The reducing capacity test shows that methanolic extract has a high antioxidant capacity (0.213±0.006) compared to ethanolic extract (0.043±0.004) but remains low compared to ascorbic acid (0.003±0.0004) which was used as reference. Conclusion: Phytochemical analysis of W. frutescens shows that this plant is rich in high quantities of alkaloids, saponins, mucilage, tannins, and coumarins. It contains an average amount of total polyphenols and tannins that confer significant antioxidant activity to the plant studied.


Author(s):  
Mazahar N Farooqui ◽  
Ali Alrabie ◽  
Ola Basaꞌar ◽  
Inas Al-Qadsy

Objective: To investigate the photochemical constituents present in methanol extract of martynia annua seeds using Gas Chromatography-Mass Spectroscopy(GC-MS), High-Performance Thin–Layer Chromatography(HPTLC) analysis and study antioxidant activity. Methods: Methanol extract of Martynia annua seeds were subjected to GC-MS and HPTLC analysis. HPTLC analysis was carried out using GAMAG system with a linomate5 applicator, system mobile phase (Toluene: Chloroform: Ethanol (4:4:1 V/V/V)), two different volume of extract was applied 2 µl and 5 µl. GC-MS analysis was carried out on JEOL GC MATE ΙΙ, column HP 5 MS and Quadruple double focusing mass analyzer. Antioxidant activity was determined by DPPH assay. Results: GC-MS analysis provided 17 peaks indicating the presence of seventeen different phytochemicals in methanol extract of martynia annua seeds. HPTLC fingerprint showed 6 peaks at both size 2 µl and 5 µl at 254 nm whereas 4 peaks, 9 peaks were detected at 366 nm for 2 µl and 5 µl respectively. After derivatization with 10 % methanolic sulphuric acid, 8 peaks, 11 peaks were detected for 2 µl and 5 µl respectively when the derivatized plate was scanned at 540 nm. DPPH free radical scavenging result showed EC50 value of 44.1±1.1 µg/ml. Conclusion: The GC-MS analysis showed the presence of fatty acids, ester, aldehydes and ketones whereas in HPTLC different peaks at different UV-lights before and after derivatization were observed. Maximum percentage inhibition using DPPH assay was found 74 at concentration of 50 µg/ml.


2021 ◽  
Vol 5 (1) ◽  
pp. 001-008
Author(s):  
Faheem I P ◽  
B. Gopalakrishna ◽  
Mohsina FP ◽  
Sarah Priya

Recently, a substantial body of literature provides strong evidence to support the potentials of Crataeva magna (CM), plant and its extracts in various pathological conditions. Thus, the CM plant extract at various concentrations were prepared and antioxidant activity was evaluated. The fresh leaves and bark of CM were collected and various extracts such as n-Hexane, Chloroform, Ethanol and aqueous extract were prepared. The preliminary phytochemical investigation showed the presence of various phytochemical such as total phenolic, flavonoid compounds and tannins. The ethanolic leaves extract of CM (ELECM) and water leaves extract of CM (WLECM), showed dose dependent increased in free radical scavenging activity in DPPH assay and reducing power assay in present study. Moreover, ethanolic barks extract of CM (EBECM) and water barks extract of CM (WBECM), also showed increased in free radical scavenging activity in DPPH assay and reducing power assay. However, the effects of bark extracts were lower than leaves extracts. In the light of the above consideration, the results of the study revealed that ELECM showed promising antioxidant activity in a dose dependent manner.


Author(s):  
Vinay M. ◽  
Seethalakshmi S. ◽  
Vijay Kumar

Background: Ormeloxifene (Centchroman) is a Selective Estrogen Receptor Modulator (SERM) which acts as estrogen antagonist and having anti progestogenic activity also. It is being used in the management of dysfunctional uterine bleeding and as nonhormonal oral contraceptive. It is also being investigated for the indications such as osteoporosis, breast and endometrial carcinoma. In this study, we have evaluated the Antioxidant potential of drug by using DPPH and NO synthase Assay. It was found that ormeloxifene has significant antioxidant activity which could be cause for its use in various gynaecological and other conditions.Methods: In this study, we have demonstrated in vitro antioxidant activity of ormeloxifene. DPPH and NO synthase assay tests were done for different concentrations of ormeloxifene.Results: In our study, it showed that the free radical scavenging activity of ormeloxifene was less in lower concentration and increased in the higher concentration in DPPH assay. The free radical scavenging activity of drug ormeloxifene was 22% at 100µg/ml and 27% for the concentrations of 1000µg/ml in DPPH assay. No scavenging activity was 3% at 100µg/ml and 11% at 1000µg/ml.Conclusions: The invitro antioxidant analysis of ormeloxifene, was proved to be a potent antioxidant.


Author(s):  
Helen William ◽  
Narayanan N

  Objective: The flavonoids are a heterogeneous group of plant polyphenols that are endowed with several biological activities including antioxidant, anti-inflammatory, immunomodulatory, antiviral, antimutagenic, and anticarcinogenic properties. They are believed to interfere with the various free radical-producing systems and they also enhance the functions of endogenous antioxidants. The aim of this study was to compare the antioxidant activity of synthesized substituted flavones by various free radical scavenging assays.Methods: The flavones used in the study, 6,3’,4’ - trihydroxy flavones (THF) and 3-hydroxy-6,3’-dimethoxy flavones were synthesized using standard procedures and their antioxidant activity was compared by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, hydrogen peroxide scavenging assay, hydroxyl radical scavenging assay, reducing power capacity, superoxide free radical scavenging assay, and 2,2′-azino-bis-3-ethylbenzthiazoline-6- sulphonic acid assay.Results: In the DPPH assay, THF has an inhibitory concentration 50% value of 18.89 μg/ml which was much better than that of standard ascorbic acid which was 26.1 μg/ml. The THF had a much better antioxidant activity in most of the free radical scavenging assays.Conclusion: From the study, it can be seen that the flavones showed significant antioxidant activity that can be used for treatment of various diseases


Foods ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 281 ◽  
Author(s):  
Saleha Akter ◽  
Michael E. Netzel ◽  
Ujang Tinggi ◽  
Simone A. Osborne ◽  
Mary T. Fletcher ◽  
...  

Terminalia ferdinandiana (Kakadu plum) is a native Australian plant containing phytochemicals with antioxidant capacity. In the search for alternatives to synthetic preservatives, antioxidants from plants and herbs are increasingly being investigated for the preservation of food. In this study, extracts were prepared from Terminalia ferdinandiana fruit, leaves, seedcoats, and bark using different solvents. Hydrolysable and condensed tannin contents in the extracts were determined, as well as antioxidant capacity, by measuring the total phenolic content (TPC) and free radical scavenging activity using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. Total phenolic content was higher in the fruits and barks with methanol extracts, containing the highest TPC, hydrolysable tannins, and DPPH-free radical scavenging capacity (12.2 ± 2.8 g/100 g dry weight (DW), 55 ± 2 mg/100 g DW, and 93% respectively). Saponins and condensed tannins were highest in bark extracts (7.0 ± 0.2 and 6.5 ± 0.7 g/100 g DW). The antimicrobial activity of extracts from fruit and leaves showed larger zones of inhibition, compared to seedcoats and barks, against the foodborne bacteria Listeria monocytogenes, Bacillus cereus, Methicillin resistant Staphylococcus aureus, and clinical isolates of Pseudomonas aeruginosa. The minimum inhibitory concentration and minimum bactericidal concentration in response to the different extracts ranged from 1.0 to 3.0 mg/mL. Scanning electron microscopy images of the treated bacteria showed morphological changes, leading to cell death. These results suggest that antioxidant rich extracts of Terminalia ferdinandiana fruits and leaves have potential applications as natural antimicrobials in food preservation.


2005 ◽  
Vol 93 (2) ◽  
pp. 227-235 ◽  
Author(s):  
Malgorzata Nogala-Kalucka ◽  
Jozef Korczak ◽  
Małgorzata Dratwia ◽  
Eleonora Lampart-Szczapa ◽  
Aleksander Siger ◽  
...  

2014 ◽  
Vol 1081 ◽  
pp. 110-114 ◽  
Author(s):  
Zhen Zhu ◽  
Hua Yin ◽  
Yan An

This research adopts the pancreatin hydrolysis of silk fibroin active peptide, evaluate the antioxidant activity of hydrolysates. In the process of hydrolysis of silk fibroin, by measuring the amino nitrogen content of neutral formaldehyde titration method. Find the amino nitrogen content gradually stabilized at around 0.37g/L, and superoxide free radical scavenging rate changing with time fluctuation trend, superoxide free radical scavenging rate to a maximum of 65.03% at 220min.The use of silk fibroin hydrolysis process optimization,reaction time 160min, enzyme concentration4% , substrate concentration 20mg/ml, pH 8, temperature 38°C. The hydrolysis process under the hydrolysate on superoxide radical scavenging rate of 72.73%. The scavenging rate of hydroxyl radical is 47.24%. Red blood cell hemolysis induced by H2O2 inhibition rate was 24.30%.


Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 48
Author(s):  
Anh Dao Thi Phan ◽  
Maral Seidi Damyeh ◽  
Saleha Akter ◽  
Mridusmita Chaliha ◽  
Michael E. Netzel ◽  
...  

Terminalia ferdinandiana (Kakadu plum), belonging to the family Combretaceae, is endemic to Australia and has a long history of traditional medicinal applications and food cuisine by the Australian Indigenous people. This study investigated the effects of maturity stages on the morphology, physicochemical parameters (total soluble solids (TSS), total acid content (TAC), and pH), soluble sugar profile and antioxidant capacity of Kakadu plum (KP) fruits that were wild harvested from different trees and classified into four different maturity stages (immature to mature). TSS and TAC were determined by standard assays/procedures, main sugars by UHPLC–MS/MS and antioxidant capacity (total phenolic content (TPC) and DPPH free radical scavenging capacity) by spectrophotometry. The results showed that soluble sugars (glucose, sucrose and fructose) ranging from 1.3 to 17.7% dry weight (DW), TSS (17.0–52.7% DW) and TAC (1.3–6.7% DW) increased with maturity. However, antioxidant capacity (TPC in the range of 7.4–21.9% DW and DPPH free radical scavenging capacity from 22 to 76% inhibition at the extract concentration of 20 g·L−1) did not follow the same trend as the one observed for soluble sugars, TSS and TAC. These differences were associated with the tree-to-tree variability as a consequence of the wild harvest condition. This study provides important information to both the KP industry and Indigenous enterprises regarding the selection of the appropriate maturity stage to harvest KP fruit to target for different markets (e.g., low-sugar vs. high-sugar fruit).


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