Significant effects of two pesticides on the bacteriostatic activity and antioxidant ability of green tea polyphenols

2020 ◽  
Author(s):  
Jin Zhang ◽  
Meng-ting Tao ◽  
Zi-yan Huang ◽  
Gui-yun Hong ◽  
Shu-guang Zhu

Abstract Background: Green tea polyphenols (GTPs) have good bacteriostatic activity and antioxidant capacity, yet pesticide pollutants in tea may affect their functionality. This study aims to explore the effects of pesticide pollutants on the bacteriostasis and antioxidant ability of GTPs.Results: The bacteriostatic activity of GTPs and two pesticides (acetamiprid (ACE), diquat dibromide (DIQ)) shows some certain time characteristics. Two pesticides can affect the bacteriostatic activity of GTPs. The bacteriostatic activity of GTPs is enhanced or weakened by the two pesticides with time lengthening, i.e. time-dependent synergism or antagonism. The bacteriostatic mechanisms of the three substances and their mixtures is produced by affecting cell morphology or destroying cell structure, and the long-term antagonism of the three substances is may due to the competition of action site. In addition, the two pesticides can greatly reduce the antioxidant capacity of GTPs. ACE reduces the free radical scavenging ability of GTPs by 14%~24% and DIQ reduces the free radical scavenging ability of GTPs by 39%~63% at the experimental concentration ratios.Conclusions: Two pesticides has significant effects on the bacteriostatic activity and antioxidant ability of GTPs.

Author(s):  
Wei-Hsun Wang ◽  
Wei-Lin Li ◽  
Cheng-You Chen ◽  
Min-Yun Chang ◽  
Shu-Ling Huang ◽  
...  

Abstract Background Chenopodium formosanum (CF) provides the human body with numerous nutritional components. This study used the two-phase system to identify an efficient method to obtain CF extracts. CF extraction was performed using an ethanol–ammonium sulfate two-phase system. The efficacy of different CF extracts with five types of antioxidant ability was tested and compared with traditional aqueous and alcohol extractions. Results The results showed that a separated top of the two-phase system extract had higher total phenol content (120.35 ± 5.80 mg gallic acid equivalent/g dry extract), total flavonoid content (447.06 ± 16.57 mg quercetin equivalent/g dry extract) and reducing ability (284.48 ± 4.60 mg vitamin C equivalent/g dry extract) than those of other extracts. Furthermore, the separated top of the two-phase system extract and the top of the two-phase system extract had higher 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging ability than those of the water extract, alcohol extract, bottom of two-phase system extract, and separated bottom of two-phase system extract. Conclusions The results indicate that CF has great potential for use in natural plant health supplements and skin care products and that the two-phase extraction system can yield an effective CF extract. Graphical Abstract


Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1207
Author(s):  
Carmen Burgos ◽  
Dolores Muñoz-Mingarro ◽  
Inmaculada Navarro ◽  
Carmen Martín-Cordero ◽  
Nuria Acero

The phenomenon of today’s ageing population has increased interest in the search for new active substances that delay the onset and development of neurodegenerative diseases. In this respect, the search for natural compounds, mainly phenolic compounds, with neuroprotective activity has become the focus of growing interest. Verbascoside is a phenylethanoid that has already presented several pharmacological activities. The purpose of this study is to isolate and identify verbascoside from Acanthus mollis leaves. Consequently, its neuroprotective ability through enzymatic inhibition and free radical scavenging ability has been analyzed both in vitro and in cell culture assays. The antioxidant capacity of verbascoside was evaluated in vitro through total antioxidant capacity, DPPH•, •OH, and O2•—scavenging activity assays. The effect of verbascoside on intracellular reactive oxygen species (ROS) levels of HepG2 and SH-SY5Y cell lines was studied in normal culture and under induced oxidative stress. The inhibitory ability of the phenylethanoid against several enzymes implied in neurodegenerative diseases (tyrosinase, MAO-A, and AChE) was analyzed in vitro. Verbascoside neuroprotective activity is at least in part related to its free radical scavenging ability. The effect of verbascoside on ROS production suggests its potential in the prevention of harmful cell redox changes and in boosting neuroprotection.


RSC Advances ◽  
2020 ◽  
Vol 10 (43) ◽  
pp. 25662-25668
Author(s):  
Jin Zhang ◽  
Meng-ting Tao ◽  
Zi-yan Huang ◽  
Gui-yun Hong ◽  
Shu-guang Zhu

Green tea polyphenols (GTPs) are widely used in food preservation because of their strong bacteriostatic activity and antioxidant ability, and whether pesticides as common pollutants in food will affect the function of GTPs is worthy of attention.


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.


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).


2020 ◽  
Vol 8 (1) ◽  
pp. 75-81
Author(s):  
Bui Van Hoai ◽  
Ngo Dai Nghiep ◽  
Dao An Quang ◽  
Nguyen Thi Nam Phuong

Chitosan with 80% degree of deacetylation was hydrolyzed by cellulase of Trichoderma viride to prepare chitooligosaccharides (COSs) by the fractionation of the COSs with ultrafiltration membrane. The antioxidant activities of the COSs were clarified in this study by reducing power and free radical scavenging ability assay by UV-VIS absorption spectrum. The results show that the COS 1 (10,000-5,000 Da), COS 2 (5,000-3,000 Da), COS 3 (3,000-1,000 Da) and COS 4 (less than1,000 Da) segments have antioxidant properties.The antioxidant activitives of the COSs increased with the increment of concentration, and they also depended on molecular weight.


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