An investigation of antioxidant capacity of fruits in Singapore markets

Effect of Cosmos caudatus (Ulam raja) supplementation in patients with type 2 diabetes: Study protocol for a randomized controlled trial

BACKGROUND

Type 2 diabetes mellitus is a major health threat worldwide. Cosmos caudatus is one of the medicinal plants used to treat type 2 diabetes. Therefore, this study aims to determine the effectiveness and safety of C. caudatus in patients with type 2 diabetes. Metabolomic approach will be carried out to compare the metabolite profiles between C. Caudatus treated diabetic patients and diabetic controls.

METHODS AND DESIGN

This is a single-center, randomized, controlled, two-arm parallel design clinical trial that will be carried out in a tertiary hospital in Malaysia. In this study, 100 patients diagnosed with type 2 diabetes will be enrolled. Diabetic patients who meet the eligibility criteria will be randomly allocated to two groups, which are diabetic C. caudatus treated(U) group and diabetic control (C) group. Primary and secondary outcomes will be measured at baseline, 4, 8, and 12 weeks. The serum and urine metabolome of both groups will be examined using proton NMR spectroscopy.

DISCUSSION

The study will be the first randomized controlled trial to assess whether C. caudatus can confer beneficial effect in patients with type 2 diabetes. The results of this trial will provide clinical evidence on the effectiveness and safety of C. caudatus in patients with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02322268.

Evaluation of Antioxidant Capacity of Solanum sessiliflorum (Cubiu) Extract: An In Vitro Assay

Cubiu is a vegetable of Solanaceae family, native to the Amazon, which is widely distributed through Brazil, Peru, and Colombia. It is used in food, medicine, and cosmetics by native populations. Research has shown that cubiu extracts have antioxidant activities with great biological relevance. We performed a phytochemical screening to identify the main chemical groups that could confer antioxidant activity to this extract. Several tests and qualitative precipitation specific staining for major classes of secondary metabolites were used. Antioxidant capacity in vitro tests (DPPH and ABTS) were also used to assess the extract's ability to sequester free radicals of 70% hydroethanolic and aqueous extracts of cubiu flour. Alkaloids, organic acids, phenols, flavonoid glycosides, and coumarins were found in the hydroethanolic extract while the aqueous extract presented anthocyanins, gums, tannins and mucilage, amino groups, and volatile and fixed acids. For in vitro tests, the IC₅₀ value obtained in the DPPH assay was 606.3 ± 3.5 μg/mL while that for the ABTS assay was 290.3 ± 10.7 µg/mL. Although cubiu extracts present chemical compounds directly related to antioxidant activity, our results show that it has a low antioxidant activity. Additional studies will be needed to isolate and characterize specific compounds to further assess antioxidant activity.

Antioxidant and tyrosinase inhibition activity of the fertile fronds and rhizomes of three different Drynaria species

Background

For generations, the rhizomes of Drynaria ferns have been used as traditional medicine in Asia. Despite this, the bioactivities of Drynaria rhizomes and leaves have rarely been studied scientifically.

Methods

This study evaluates the antioxidant properties of the methanolic extracts of the fertile fronds and rhizomes from three species in this genus: Drynaria quercifolia, Drynaria rigidula and Drynaria sparsisora. The phenolic and flavonoid contents of the samples were respectively quantified with the total phenolic content (TPC) and total flavonoid content (TFC) assays, while the antioxidant activities were determined via measuring the DPPH radical scavenging activity (FRS), ferric reducing power (FRP), ferrous ion chelating (FIC) activity and lipid peroxidation inhibition (LPI). The tyrosinase inhibition activity of all three species was also reported.

Results

The fertile fronds of D. quercifolia were found to exhibit the highest overall TPC (2939 ± 469 mg GAE/100 g) and antioxidant activity amongst all the samples, and the fertile fronds of D. quercifolia and D. rigidula exhibited superior TPC and FRP compared to their rhizomes, despite only the latter being widely used in traditional medicine. The fronds of D. quercifolia had high tyrosinase inhibition activity (56.6 ± 5.0 %), but most of the Drynaria extracts showed unexpected tyrosinase enhancement instead, particularly for D. sparsisora’s fronds.

Conclusion

The high bioactivity of the fertile fronds in the fern species indicate that there is value in further research on the fronds of ferns which are commonly used mostly, or only, for their rhizomes.

Effects of Ultrasound on Spoilage Microorganisms, Quality, and Antioxidant Capacity of Postharvest Cherry Tomatoes

Mature-green cherry tomato fruits (Lycopersicon esculentum cv. Jinyu) were exposed to different power densities of ultrasound (66.64, 106.19, and 145.74 W/L) at 25 °C to study ultrasound non-thermal effects on the storage properties. Among the three levels of ultrasound irradiation, 106.19 W/L ultrasound was effective in reducing the spoilage microorganisms, delaying postharvest ripening through inhibiting ethylene production and respiration rates, and consequently maintaining fruit firmness, flavor, enzyme activities, antioxidants (total phenolics, total flavonoids), and the total antioxidant capacity of cherry tomatoes. The 66.64 W/L ultrasound had similar effects but to a lesser extent. Meanwhile, although 145.74 W/L ultrasound resulted in higher content of ascorbic acid (AA), it showed many negative effects on the storage quality of fruits. These results demonstrated that ultrasound of appropriate power density had great potentials in inhibiting decay, maintaining flavor and nutritional quality of cherry tomatoes.

PRACTICAL APPLICATION

Recently, ultrasound has been considered as a multifunctional pretreatment method for the preservation of postharvest fruits and vegetables. Although the preservation effects were slight because of the screening of the thermal effects, its non-thermal effects presented potentials in improving storage quality of cherry tomato. Further studies are needed to explore the combinations between ultrasound with heating as well as other postharvest preservation technologies to enhance the effects of ultrasound. These explorations would facilitate the large-scale application of ultrasound in the preservation of fresh fruits and vegetables.

In vitro and in vivo bioactivities of aqueous and ethanol extracts from Helicteres angustifolia L. root

ETHNOPHARMACOLOGICAL RELEVANCE

Helicteres angustifolia L. (H. angustifolia L.) has been used as traditional medicine in the treatment of cancer in China and Laos. Its medical benefits, however, are still lacking of scientific evidence. Two extracts successively obtained from the root of H. angustifolia L., namely the aqueous root extract (ARE) and the ethanolic root extract (ERE), were used to evaluate the antioxidant and anticancer activities in vitro, and the antitumor efficacy of ARE was examined in vivo, respectively.

MATERIALS AND METHODS

ARE and ERE were extracted successively from H. angustifolia L. root with water and ethanol. In vitro antioxidant activities were assessed by radicals scavenging assay, ferrous chelating assay and reducing power assay. In vitro anticancer activities of ARE and ERE were evaluated by their cytotoxic effects against three human cancer cell lines. In addition, the anti-tumor activities of ARE in vivo were assessed by using Ht1080 (human fibrosarcoma cell line Ht1080) tumor xenografts mice. BALB/c nude mice were orally administrated with 200mg/kg/d of ARE. The tumor inhibition rate was determined on day 42 after treatment by using histopathology analysis of the tumor tissues. Furthermore, relevant biochemical parameters in blood were analyzed to monitor their cytotoxic effect.

RESULTS

In vitro assays indicated that ARE possessed relatively higher antioxidant and anticancer activities than ERE, with IC50 values of 82.31 ± 9.62, 62.50 ± 6.99, and 127.49 ± 2.9 μg/mL against DLD-1, A549, and HepG2 cells, respectively. In vivo tumor inhibition experiments suggested that ARE possessed significant antitumor efficacy in BALB/c nude mice with a tumor inhibition rate of 49.83 ± 14.38% (p<0.05) and little toxicity was observed to the host.

CONCLUSION

ARE from H. angustifolia L. possessed high antioxidant activities is active against liver cancer HepG2, lung cancer A549 and colon cancer DLD-1 cells in vitro and tumor xenografts bearing BALB/c nude mice in vivo. Further studies on elucidation of the mechanisms involved and isolation of the active components may provide more valuable information for the development of functional products from H. angustifolia L. and their application in cancer treatment.

Antioxidant potential, total phenolic and total flavonoid contents of Rhododendron anthopogonoides and its protective effect on hypoxia-induced injury in PC12 cells

BACKGROUND

Rhododendron anthopogonoides Maxim, a kind of traditional Tibetan medicine, has been used to remove body heat, body detoxification, cough, asthma, stomachic and swelling, eliminate abundant phlegm and inflammatory for a long time. In the present study, the total phenols and total flavonoid contents as well as antioxidative properties of the crude extract and solvent fractions of R. anthopogonoides were determined using seven antioxidant assays. Additionally, the protective effect of the extracts on hypoxia-induced injury in PC12 cells was also investigated.

METHODS

The content of total flavonoid and total phenolic was determined by the aluminum colorimetric method and Folin-Ciocalteu assay, respectively. In vitro antioxidant study, the effect of the crude extract and solvent fractions on total antioxidant activity, reducing power, DPPH radical scavenging, ABTS radical scavenging, superoxide radical scavenging, hydroxyl radical scavenging and nitric oxide radical scavenging were examined. The correlation between the phenolic and flavonoid content of the extracts and their antioxidant properties also analyzed. Furthermore, the protective effect of extracts on hypoxia-induced damage on PC12 cells was investigated by cell viability, lactate dehydrogenase (LDH) release, malondialdehyde (MDA) production and the activities of antioxidant enzymes.

RESULTS

Our results showed that ethyl acetate and n-butanol fractions had higher content of phenolics and flavonoid compounds than other fractions. Except ABTS radical assay, n-butanol fraction exhibited the strongest antioxidant activity. While the hexane fraction showed the lowest antioxidant activity. Ethyl acetate also presented excellent antioxidant activity, which was just lower than n-butanol fraction. Significant correlation between the phenolic, flavonoid content of the extract and fractions with antioxidant assay excluding ABTS, OH scavenging assay was observed. Moreover, ethyl acetate and n-butanol fractions showed protective effect in PC12 cell under hypoxia condition, while crude extract and water fraction had no protective effect. In contrast, hexane fraction exhibited strong cytoprotective effect. Further study indicated that pretreatment of PC12 cells with ethyl acetate and n-butanol fractions, prior to hypoxia exposure, significantly increased the survival of cells and the activities of SOD, CAT, GSH-Px and T-AOC, as well as reduced the level of LDH and MDA. The gathered data demonstrated that ethyl acetate and n-butanol fractions were able to protect PC12 cells against hypoxia induced injury through direct free radical scavenging and modulation of endogenous antioxidant enzymes.

CONCLUSION

These findings suggested that ethyl acetate and n-butanol fractions of R. anthopogonoides had significant antioxidant activity and could prevent PC12 cells against hypoxia-induced injury. So it might be regarded as an excellent source of antioxidants and had great potential to explore as therapeutic agent for preventing hypoxia related sickness in future.

Antioxidant activity and optimization of extraction of polysaccharide from the roots of Dipsacus asperoides

Polysaccharide extraction from Dipsacus asperoides roots (DAP) was proved to possess strong antioxidant activities, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azobis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities, inhibiting β-carotene bleaching and strong reducing power. Cell assay demonstrated that the crude DAP possessed antioxidant activity and were effective against H2O2-induced L02 cells injury. Then, response surface methodology (RSM) was applied to optimize the ultrasonic extraction of DAP. The optimum variables given by central composite design (CCD) were as follows: ratio of water to raw material, 38.61mL/g; ultrasonic power, 308.68W; extraction time, 38.61min; and extraction temperature, 89°C. Under these conditions, the maximum yield of DAP obtained was 7.12±0.45%. Moreover, high performance liquid chromatography (HPLC) analysis suggested that the monosaccharide compositions of DAP contained primarily mannose, ribose, glucose, galactose, xylose and arabinose, with a molar ratio of 0.22:0.48:2.29:0.34:1.39:1.41. The results of the present study showed that DAP could be considered as potential sources of natural antioxidants.

The influence of different drying methods on constituents and antioxidant activity of saffron from china

More and more saffron has been cultivated in China because of the increasing saffron demand, but no paper has studied the influence of drying methods on the quality of Chinese saffron. In this paper, three different dehydration treatments applied in actual production were evaluated: dehydration with electric oven, vacuum oven, and microwave. We determined that the highest quality of saffron will be obtained when fresh saffron is treated at higher temperatures (no more than 70°C) for a long time by electric oven drying and vacuum oven drying. In microwave drying, treatments at lower microwave power and longer time benefit the quality of saffron. In addition, the influence of the drying method on antioxidants in saffron is discussed. The correlation between individual saffron profiles and the antioxidant value was estimated by spectrum-effect relationships analysis.

Antioxidant Activity of Allium hookeri Root Extract and Its Effect on Lipid Stability of Sulfur-fed Pork Patties

This study was performed to assess the antioxidant activity of Allium hookeri root extract (AHE) on lipid oxidation of raw sulfur-fed pork patties for 14 d of refrigerated storage. Different concentration of ethanol (0-100%) and time (1-12 h) were applied to determine the extraction condition. Water (0% ethanol) extraction for 1 h was selected as an optimal extraction condition of AHE for the following study showing the highest total phenolic content and total flavonoid content, as well as the strongest antioxidant activity. The 1% AHE (SP1), 3% AHE (SP2), and 0.05% ascorbic acid (SP3) were added into sulfur-fed pork patties against controls; SP0 (sulfur-fed pork patties with no AHE) and P0 (normal pork patties with no AHE). The pH values of P0 and SP0 significantly increased (p<0.05) than others on 14 d and redness of P0 showed the largest decrement during storage. P0 and SP0 showed higher production of conjugated dienes on d 7 than others (p<0.05). Thiobarbituric acid reactive substances (TBARS) values were decreased in proportion to the increased level of AHE on 14 d (p<0.05) resulting in higher TBARS values on P0 and SP0 (p<0.05) and the negative correlation between AHE level and TBARS were also demonstrated (r=-0.910, p=0.001). Therefore, the results suggest that AHE effectively retarded the lipid oxidation rate of sulfur-fed pork patties indicating the potential usage of AHE as a natural preservative.

Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications

A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ∼40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4 days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48 h incubation with 7 days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.

Assessment of antioxidant and antiproliferative properties of spinach plants grown under low oxygen availability

BACKGROUND

In the human diet, the consumption of fresh fruits and vegetables is important in maintaining good health and in preventing chronic diseases. It is known that plant-derived food is a powerful source of chemopreventive molecules, i.e. antioxidants, and spinach (Spinacia oleracea L., Chenopodiaceae) possesses a wide range of metabolites with such biological activity. Plant stress response could lead to the production of metabolites with high value for human health and this could be a tool to enhance the production of molecules with antioxidant activity in plants.

RESULTS

Data reported in this paper confirm the antioxidant properties of spinach plants, and show a strong antiproliferative activity of leaf extract on HT-29 human cell line. Besides, the hypoxic stress seems to affect the pool of antioxidant molecules present in spinach leaves, as verified by means of HPLC-MS/MS analysis and the aluminium chloride and ABTS assays.

CONCLUSION

Our findings represent a basis for improving the biological and pharmacological properties of spinach plants, including the use of different growth conditions to modulate the phytocomplex profile of spinach.

Schiff's bases of quinazolinone derivatives: Synthesis and SAR studies of a novel series of potential anti-inflammatory and antioxidants

A series of quinazolinone derived Schiff base derivatives 7-28 were synthesized and characterized as novel antioxidants and anti-inflammatory agents. The in vitro antioxidant activities of these compounds were evaluated and compared with commercial antioxidants ascorbic acid (AA), gallic acid (GA), butylatedhydroxytoluene (BHT), butylatedhydroxyanisole (BHA) employing 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay, 2,2-azinobis-(3-ethylbenzothiazoline-6-sufonic acid) (ABTS) assay and N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) assay. The results revealed that IC50 of 17, 18, 23, 24, 25, 27 and 28 were lower than the IC50 of standards in all the three performed antioxidant assays indicating good activities of these compounds. In addition, in vitro anti-inflammatory activity of the synthesized compounds were evaluated and the results demonstrate that the compounds 9-12 exhibited excellent anti-inflammatory activity. Preliminary structure-activity relationship revealed that the compounds 17, 18, 23, 24, 25, 27 and 28 with electron donating moiety (OH, OCH3) were found to be excellent antioxidants and compounds 9, 10, 11 and 12 with electron withdrawing moiety (Cl, NO2) were found to be excellent anti-inflammatory agents.

Coccoloba uvifera(L.) (Polygonaceae) Fruit: Phytochemical Screening and Potential Antioxidant Activity

The flora of Latin America attracts gaining interest as it provides a plethora of still unexplored or underutilized fruits that can contribute to human well-being due to their nutritional value and their content of bioactive compounds. Antioxidant compounds are now of considerable interest due to their effect of preventing or delaying aging and their apparent involvement in prevention of numerous human diseases, including cancer, atherosclerosis, Alzheimer’s disease, inflammation, and rheumatoid arthritis. In this work, the fruit ofCoccoloba uvifera(L.) was investigated for theirin vitroantioxidant capacity using two assays based on reactions with a relatively stable single reagent radical (Trolox equivalent antioxidant capacity, TEAC; and DPPH free radical scavenging assay, DPPH), two assays based on chelating of metallic cations, and one based on the reduction of oxidized species. The TEAC value on ABTS radical, DPPH scavenging activity, ion chelation, and reducing power were found to be 897.6 μM of Trolox/100 g of sample, 22.8% of DPPH free radical scavenging, 11.3% of Cu2+-chelating activity, 23.9% of Fe2+-chelating activity, and a Fe2+-reducing power of 0.76 mg/mL, respectively. The free radical scavenging and antioxidant characteristics ofC. uviferamay be due to the presence of diverse phytochemicals in the fruit as anthocyanins, ascorbic acid, phenolic compounds, and flavonoids.

Synthesis and characterization of steroidal heterocyclic compounds, DNA condensation and molecular docking studies and their in vitro anticancer and acetylcholinesterase inhibition activities

A facile and efficient approach for the synthesis of steroidal heterocyclic compounds (4–12) has been performed. Furthermore, these newly synthesized compounds were evaluated for their various biological activities.

New insights into the anti-obesity activity of xanthones from Garcinia mangostana

This article reviews the anti-adipogenic, anti-inflammatory and antioxidant activities of xanthones from Garcinia mangostana.

Assessment of antioxidant activities in roots of Miswak (Salvadora persica) plants grown at two different locations in Saudi Arabia

Traditionally, in Middle Eastern countries, many cultures use chewing sticks of arak for medicinal purposes especially, for oral cleanliness care. It was used by Muslims for treatment of teeth and highly recommended to be used by Muslims during the whole day. Therefore, the present work aimed to determine the total phenolic content and total flavonoids in two Miswak extracts obtained from arak roots collected from two different localities in Saudi Arabia. They were extracted with aqueous ethanol (80%) and used to estimate in vitro their antioxidative abilities. The new findings showed that the two tested extracts contained significantly different amounts of both total phenolic content and total flavonoids. According to the increase of total phenolic contents and total flavonoids obtained from the two extracts, Miswak collected from the southern region was found to contain more contents than those collected from the middle region. The results of antioxidant activities of Miswak root extract obtained by using different in vitro methods were varied depending on the technique used. According to the malondialdehyde (MDA) method, hydrogen peroxide (H₂O₂) scavenging ability and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, the two Miswak extracts exhibited to have high to very high antioxidant activities. Mostly, the values of antioxidant activities of Southern region have been shown to be always the highest.

A Caco-2 cell-based quantitative antioxidant activity assay for antioxidants

A Caco-2 cell-based antioxidant activity (CAA) assay for quantitative evaluation of antioxidants was developed by optimizing seeding density and culture time of Caco-2 cells, incubation time and concentration of fluorescent probe (2',7'-dichlorofluorescin diacetate, DCFH-DA), incubation way and incubation time of antioxidants (pure phytochemicals) and DCFH-DA with cells, and detection time of fluorescence. Results showed that the CAA assay was of good reproducibility and could be used to evaluate the antioxidant activity of antioxidants at the following conditions: seeding density of 5 × 10(4)/well, cell culture time of 24h, co-incubation of 60 μM DCFH-DA and pure phytochemicals with Caco-2 cells for 20 min and fluorescence recorded for 90 min. Additionally, a significant correlation was observed between CAA values and rat plasma ORAC values following the intake of antioxidants for selected pure phytochemicals (R(2) = 0.815, p < 0.01), demonstrating the good biological relevance of CAA assay.

Antioxidant property of coffee components: assessment of methods that define mechanisms of action

Coffee is a rich source of dietary antioxidants, and this property, coupled with the fact that coffee is one of the world's most popular beverages, has led to the understanding that coffee is a major contributor to dietary antioxidant intake. Brewed coffee is a complex food matrix with numerous phytochemical components that have antioxidant activity capable of scavenging free radicals, donating hydrogen and electrons, providing reducing activity and also acting as metal ion pro-oxidant chelators. More recent studies have shown that coffee components can trigger tissue antioxidant gene expression and protect against gastrointestinal oxidative stress. This paper will describe different in vitro, cell-free and cell-based assays that both characterize and compare the antioxidant capacity and mechanism of action of coffee and its bioactive constituents. Moreover, evidence of cellular antioxidant activity and correlated specific genomic events induced by coffee components, which are relevant to antioxidant function in both animal and human studies, will be discussed.