Screening p-Phenylenediamine Antioxidants, Their Transformation Products, and Industrial Chemical Additives in Crumb Rubber and Elastomeric Consumer Products.

Recently, roadway releases of N,N'-substituted p-phenylenediamine (PPD) antioxidants and their transformation products (TPs) received significant attention due to the highly toxic 6PPD-quinone. However, the occurrence of PPDs and TPs in recycled tire rubber products remains uncharacterized. Here, we analyzed tire wear particles (TWPs), recycled rubber doormats, and turf-field crumb rubbers for seven PPD antioxidants, five PPD-quinones (PPDQs), and five other 6PPD TPs using liquid chromatography-tandem mass spectrometry. PPD antioxidants, PPDQs, and other TPs were present in all samples with chemical profiles dominated by 6PPD, DTPD, DPPD, and their corresponding PPDQs. Interestingly, the individual [PPDQ]/[PPD] and [TP]/[PPD] ratios significantly increased as total concentrations of the PPD-derived chemical decreased, indicating that TPs (including PPDQs) dominated the PPD-derived compounds with increased environmental weathering. Furthermore, we quantified 15 other industrial rubber additives (including bonding agents, vulcanization accelerators, benzotriazole and benzothiazole derivatives, and diphenylamine antioxidants), observing that PPD-derived chemical concentrations were 0.5-6 times higher than these often-studied additives. We also screened various other elastomeric consumer products, consistently detecting PPD-derived compounds in lab stoppers, sneaker soles, and rubber garden hose samples. These data emphasize that PPD antioxidants, PPDQs, and related TPs are important, previously overlooked contaminant classes in tire rubbers and elastomeric consumer products.

Dietary Plant Polyphenols as the Potential Drugs in Neurodegenerative Diseases: Current Evidence, Advances, and Opportunities.

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), are characterized by the progressive degeneration of neurons. Although the etiology and pathogenesis of neurodegenerative diseases have been studied intensively, the mechanism is still in its infancy. In general, most neurodegenerative diseases share common molecular mechanisms, and multiple risks interact and promote the pathologic process of neurogenerative diseases. At present, most of the approved drugs only alleviate the clinical symptoms but fail to cure neurodegenerative diseases. Numerous studies indicate that dietary plant polyphenols are safe and exhibit potent neuroprotective effects in various neurodegenerative diseases. However, low bioavailability is the biggest obstacle for polyphenol that largely limits its adoption from evidence into clinical practice. In this review, we summarized the widely recognized mechanisms associated with neurodegenerative diseases, such as misfolded proteins, mitochondrial dysfunction, oxidative damage, and neuroinflammatory responses. In addition, we summarized the research advances about the neuroprotective effect of the most widely reported dietary plant polyphenols. Moreover, we discussed the current clinical study and application of polyphenols and the factors that result in low bioavailability, such as poor stability and low permeability across the blood-brain barrier (BBB). In the future, the improvement of absorption and stability, modification of structure and formulation, and the combination therapy will provide more opportunities from the laboratory into the clinic for polyphenols. Lastly, we hope that the present review will encourage further researches on natural dietary polyphenols in the treatment of neurodegenerative diseases.

Nanoformulations of quercetin: a potential phytochemical for the treatment of uv radiation induced skin damages

Abstract The continuous prolonged exposures of sun light especially the ultra violet (UV) radiation present in it, cause not only the risk of skin cancer but also it may cause premature skin aging, photodermatoses and actinic keratoses. Flavonoids (including Flavane, Flavanone, Flavone, Flavonol, Isoflavone, Neoflavone etc.) having potent antioxidant activity, used as topical applications for protection against UV induced skin damages as well as for skin care. Most commonly used flavonoid is quercetin (Flavonol), which is present in fruits, vegetables, and herbs. We aim to review the research focused on development of different novel formulations to treat UV radiations induced skin diseases. In this review, several formulations of flavonoid quercetin were discussed and their outcomes were compiled and compared in context to solubility, stability and efficiency of application. On the basis this comparative analysis we have concluded that three formulations, namely glycerosomes, nanostructured lipid carriers and deformable liposomes hold good applications for future aspects for topical delivery of quercetin. These formulations showed enhanced stability, increased quercetin accumulation in different skin layers, facilitated drug permeation in skin and long-lasting drug release.

Composition, Antioxidant and Anti-inflammatory activities of Hexane and Methanol extracts of Acmella uliginosa from Terai region of Uttarakhand

Abstract Acmella uliginosa, an edible herb belonging to Asteraceae family, was collected from the Terai region of Uttarakhand, India. Methanol and hexane extracts of the whole plant were prepared using soxhlet apparatus. The GC-MS analysis of plant extracts identifies 22 and 35 major compounds of methanol and hexane extracts which comprises of 74.21% and 73.20% of the total composition of extracts, respectively. The major compound in hexane was 2, 4-heptadienal (7.99%) whereas trans, trans-9, 12-octadecadienoic acid propyl ester (16.96%) was major compound in methanol extract. The extracts were evaluated for antioxidant and anti-inflammatory properties. Methanol extract showed higher free radical scavenging and reducing power activities with IC50 value 153.82±1.69 µg/mL and RP50 value of 152.28±0.41 µg/mL, respectively. The metal chelating activity was higher in hexane extract as compared to methanol extract i.e., 62.08±0.25 µg/mL. The anti-inflammatory activity assessed by its ability to inhibit denaturation was higher in methanol having IB50 value 87.33±0.15 µg/mL. The total phenolic content (TPC), total flavonoid content (TFC) and ortho-dihydric phenol content (ODP) of methanol and hexane extracts were also evaluated. TPC, TFC and ODP was higher in methanol extract having value of 122.23±0.22, 35.01±0.29 and 8±0.86 mg/mL, respectively. Acmella uliginosa, might be considered as a natural source for antioxidant and anti-inflammatory properties

Curcuma longa extract protects against 5-fluorouracil-induced oral mucositis in hamsters

Abstract Curcumin, contained at Turmeric (Curcumalonga), can exert many beneficial pleiotropic activities in the gastrointestinal tract. This study evaluated the antioxidant and anti-inflammatory activity of C. longa on 5-fluorouracil (5-FU)-induced oral mucositis (OM) in hamsters. Phytochemical analysis of crude C. longa extract (CLE) was performed to detect the presence of curcumin by TLC and HPLC. Golden Syrian hamsters were orally pre-treated with CLE (5, 50, or 100mg/kg). Cheek pouch samples were subjected to macroscopic and histopathological evaluation. ELISA was performed to quantify the inflammatory cytokines IL-1ß and TNF-α. Superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) levels were assessed by ultraviolet-visible spectroscopy analysis. Behavior analysis was conducted by the open field test. Curcumin content in the CLE was 0.55%m/m ± 0.0161 (2.84%). The group treated with 5mg/kg CLE showed healing evidence with macroscopic absence of ulceration (p<0.05) and microscopic aspect of re-epithelialization, discrete inflammatory infiltrate and absence of edema. Treatment with 5mg/kg CLE significantly increased GSH levels, and reduced MDA levels and SOD activity (p˂0.05), and decreased IL-1ß (p˂0.05) and TNF-α (p˂0.01) levels. A significant reduction in walking distance, ambulation, speed, and rearing was observed for motor activity. Curcumin reduced oxidative stress, inflammation, and motor activity in hamsters with 5-FU-induced OM.

Synthesis and characterization of Sophora alopecuroides L. green synthesized of Ag nanoparticles for the antioxidant, antimicrobial and DNA damage prevention activity

Abstract In this study, it was aimed to investigate the amount of antioxidant, protective properties against DNA damage and antibacterial properties against various pathogens after the interaction of Ag metal (Ag NPs/Sa) of Sophora alopecuroides L. (S. alopecuroides L) plant seed, which is grown in Igdir and used in the treatment of many diseases. The DPPH radical quenching activity of Ag NPs/Sa was performed by using Blois method, DNA damage prevention activity by gel electrophoresis and antibacterial property by disk diffusion method. With the green synthesis method, AgNPs obtained as a result of the reaction of the plant and Ag metal are UV visible spectrophotometer (UV-vis), fourier-transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). DPPH radical quenching activity of Ag NPs/Sa was investigated in the concentration range of 25-250 µg/ml. The radical quenching activity at a concentration of 250 µg/ml was 85,215 ± 0,101%, while this value was 93,018% for the positive control BHA. It has been observed that the protective property of pBR322 plasmid DNA damage against OH radicals originating from H2O2 increases with concentration. It has been observed that Ag NPs/Sa has significant antimicrobial properties against some pathogens (B. subtilis ATCC 6633 E. coli ATCC 25952, B. cereus ATCC 10876, P. aeruginosa ATCC 27853, E. faecalis ATCC 29212, S. aureus ATTC 29213 and C. albicans ATTC 90028) that cause disease and even some pathogens are more effective than antibiotics

The effect of lithium tetraborate as a novel cardioprotective agent after renal ischemia-reperfusion injury

Abstract Epidemiological studies suggest that acute kidney injury has certain effect on myocardial function. In this study, for the first time, we tested a boron compound namely lithium tetraborate an act as an anti-oxidant and anti-inflammatory agent in ischemia-reperfusion injury. For this, we employed an in vivo rat model with kidney ischemia reperfusion injury to evaluate cardiac injury to clarify the mechanisms of lithium tetraborate. The evaluation of cardiac injury through kidney artery occlusion and reperfusion rat model indicated that lithium tetraborate could (1) reduce oxidative stress-induced endothelial dysfunction; (2) attenuate the inflammatory response of cardiac cells; and (3) alleviate the apoptosis and necrosis of myocytes. In summary, lithium tetraborate demonstrates significant therapeutic properties that contribute to the amelioration of cardiac damage, and it could be a promising candidate for future applications in myocardial dysfunction.

Efficacy of an herbal compound in decreasing steatosis and transaminase activities in non-alcoholic fatty liver disease: A randomized clinical trial

Abstract Hepatoprotective effects of many herbal agents have been reported in animal studies and clinical trials. In this study, five hepatoprotective plants with potent antioxidant, anti-inflammatory, and hypolipidemic effects were chosen to prepare a polyherbal compound for managing NAFLD. Sixty patients with NAFLD were randomly divided into treatment and control groups (2:1 ratio). Both group were advised to take healthy diet and exercise. The treatment group also received herbal capsules containing 400 mg of the mixture of Anethum graveolens, Citrus aurantium, Cynara scolymus, Portulaca oleracea, and Silybum marianum (2 capsules, thrice daily, for two months). The liver ultrasound and biochemical markers including the serum lipids, liver enzymes, and glucose were evaluated before starting the study and at the end of the treatment. Thirty patients in the treatment group and sixteen patients in the control group completed the study. The herbal compound significantly decreased the serum level of alanine transaminase (ALT), aspartate transaminase (AST), and total cholesterol. Treatment with the herbal compound significantly improved the grade of the fatty liver, but no significant change was found in the control group. In conclusion, the formulated herbal compound appeared to be effective in biochemical improvement and decreasing the grade of the fatty liver in the patients with NAFLD.

The Therapeutic Potential of Cannabis in Counteracting Oxidative Stress and Inflammation.

Significant growth of interest in cannabis (Cannabis sativa L.), especially its natural anti-inflammatory and antioxidative properties, has been observed recently. This narrative review aimed to present the state of the art of research concerning the anti-inflammatory activity of all classes of cannabinoids published in the last five years. Multimodal properties of cannabinoids include their involvement in immunological processes, anti-inflammatory, and antioxidative effects. Cannabinoids and non-cannabinoid compounds of cannabis proved their anti-inflammatory effects in numerous animal models. The research in humans is missing, and the results are unconvincing. Although preclinical evidence suggests cannabinoids are of value in treating chronic inflammatory diseases, the clinical evidence is scarce, and further well-designed clinical trials are essential to determine the prospects for using cannabinoids in inflammatory conditions.

Phenolic Profiles of Ten Australian Faba Bean Varieties.

Although Australia is the largest exporter of faba bean globally, there is limited information available on the levels of bioactive compounds found in current commercial faba bean varieties grown in this country. This study profiled the phenolic acid and flavonoid composition of 10 Australian faba bean varieties, grown at two different locations. Phenolic profiling by HPLC-DAD revealed the most abundant flavonoid to be catechin, followed by rutin. For the phenolic acids, syringic acid was found in high concentrations (72.4-122.5 mg/kg), while protocatechuic, vanillic, p-hydroxybenzoic, chlorogenic, p-coumaric, and trans-ferulic acid were all found in low concentrations. The content of most individual phenolics varied significantly with the variety, while some effect of the growing location was also observed. This information could be used by food processors and plant breeders to maximise the potential health benefits of Australian-grown faba bean.

Accurate Identification of Antioxidant Proteins Based on a Combination of Machine Learning Techniques and Hidden Markov Model Profiles.

Antioxidant proteins (AOPs) play important roles in the management and prevention of several human diseases due to their ability to neutralize excess free radicals. However, the identification of AOPs by using wet-lab experimental techniques is often time-consuming and expensive. In this study, we proposed an accurate computational model, called AOP-HMM, to predict AOPs by extracting discriminatory evolutionary features from hidden Markov model (HMM) profiles. First, auto cross-covariance (ACC) variables were applied to transform the HMM profiles into fixed-length feature vectors. Then, we performed the analysis of variance (ANOVA) method to reduce the dimensionality of the raw feature space. Finally, a support vector machine (SVM) classifier was adopted to conduct the prediction of AOPs. To comprehensively evaluate the performance of the proposed AOP-HMM model, the 10-fold cross-validation (CV), the jackknife CV, and the independent test were carried out on two widely used benchmark datasets. The experimental results demonstrated that AOP-HMM outperformed most of the existing methods and could be used to quickly annotate AOPs and guide the experimental process.

Changes in the Antioxidative Activity and the Content of Phenolics and Iridoids during Fermentation and Aging of Natural Fruit Meads.

The aim of the study was to investigate changes in the content of biologically active compounds during the fermentation and aging of natural meads with the addition of three Cornelian cherry juices from three cultivars: 'Koralovyi', 'Podolski' and 'Yantarnyi', in the amount of 10% v/v. After the fermentation process the content of gallic and ellagic acids significantly increased, in relation to wort. Whereas the greatest losses were observed among unstable anthocyanins. The three-month aging process also reduced the content of the analyzed compounds except for ellagic acid, the content of which increased by up to 90%. The content of biologically active compounds, including iridoids and antioxidant phenolics, are constantly changing in the process of fermentation and aging of fruit meads. The studies proved that the addition of Cornelian cherry juice allows significantly enriched classic meads with new biologically active compounds, such as: exceptional iridoids (loganic acid, cornuside, loganine, sweroside), flavonols, phenolic acids and anthocyanins.

Phytochemical Profile and Antioxidant Activity of Nigella sativa L Growing in Morocco.

BACKGROUND: Nigella sativa L (NS) is a powerful antioxidant and medicinal plant with many therapeutic applications particularly in traditional medicine for respiratory, gastrointestinal, rheumatic, and inflammatory disorders, as well as cancer. OBJECTIVE: The aim of this study is to extract the active ingredients from the Moroccan Nigella sativa L and determine its antioxidant properties. We hypothesize that the separation of the compounds from Nigella sativa L has either a positive or negative effect on antioxidants. To study this, we explored different methods to simultaneously extract and separate compounds from Nigella sativa L and performed antioxidant tests (ß-carotene and DPPH) for all collected fractions. METHODS: Nigella sativa L was hot-extracted by Soxhlet and mother extracts and was separated using silica column chromatography with adequate eluents. Qualitative phytochemical tests to determine the chemical families in Nigella sativa L seeds were performed on the fractions. They were also identified and characterized by GC-MS and HPLC-DAD. Then, antioxidant activity was examined by ß-carotene bleaching and DPPH radical scavenger tests. Results and Conclusion. The mother extract hexane FH generated eight different fractions (SH1-8) and the acetone extract FA generated 11 fractions (SA1-11). The FH fractions had a high percentage of fatty acids, and the FA fractions had some interesting polyphenols derivative compounds. Phytochemical screening revealed secondary metabolites such as polyphenols flavonoids, alkaloids, steroids, terpenes coumarins, tannins, and saponins. We found that only two solvents (hexane, acetone) of different polarities could easily extract and simultaneously separate the components of Nigella sativa L. The antioxidant fractions that we collected had close activity to reference compounds but were more active than the corresponding mother extracts. Moreover, several IC50 values of fractions from acetone extract were better than those from hexane. Therefore, the antioxidant activity of Nigella sativa L is more attributed to flavonoids and polyphenols than fatty acids. In summary, the separation of hexane extract presents a more pronounced positive effect for antioxidant tests than acetone extract.

Evaluation of Antioxidant and Enzyme Inhibition Properties of Croton hirtus L'Hér. Extracts Obtained with Different Solvents.

Croton hirtus L'Hér methanol extract was studied by NMR and two different LC-DAD-MSn using electrospray (ESI) and atmospheric pressure chemical ionization (APCI) sources to obtain a quali-quantitative fingerprint. Forty different phytochemicals were identified, and twenty of them were quantified, whereas the main constituents were dihydro α ionol-O-[arabinosil(1-6) glucoside] (133 mg/g), dihydro ß ionol-O-[arabinosil(1-6) glucoside] (80 mg/g), ß-sitosterol (49 mg/g), and isorhamnetin-3-O-rutinoside (26 mg/g). C. hirtus was extracted with different solvents-namely, water, methanol, dichloromethane, and ethyl acetate-and the extracts were assayed using different in vitro tests. The methanolic extracts presented the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) values. All the tested extracts exhibited inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with a higher activity observed for dichloromethane (AChE: 5.03 and BChE: 16.41 mgGALAE/g), while the methanolic extract showed highest impact against tyrosinase (49.83 mgKAE/g). Taken together, these findings suggest C. hirtus as a novel source of bioactive phytochemicals with potential for commercial development.

Synthesis of novel sulfonamides with anti-Alzheimer and antioxidant capacities.

A series of novel dopamine analogs incorporating urea and sulfonamide functional groups was synthesized from 3,4-dimethoxyphenethylamine. The reaction of 3,4-dimethoxyphenethylamine with N,N-dimethylcarbamoyl chloride, followed by the sulfonyl chlorination of the urea derivative, gave benzene-1-sulfonyl chloride 9, which was reacted with NH3 (aq) or N-alkyl amines to give related sulfonamides. The O-demethylation reaction of the subsequent compounds with BBr3 afforded four novel phenolic dopamine analogs including sulfonamide and urea in the same structure. The anticholinergic and antioxidant effects of the synthesized compounds were examined. Compound 13 exhibited inhibition at the micromolar level for both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The IC50 value of 13 was calculated as 298 ± 43 µM for AChE and 321 ± 29 µM for BChE. The antioxidant and antiradical effects of the molecules were investigated by five different methods. Among the synthesized compounds 10-18, the best antioxidant and antiradical activities belong to the phenolic compounds 15-18. Compounds 16 and 18 have a higher reducing power than the standards used, that is, butylated hydroxytoluene, butylated hydroxyanisole, Trolox, and α-tocopherol, for Fe3+ -Fe2+ and Cu2+ -Cu+ reducing activities. For the DPPH• radical scavenging method, compounds 16-18 have a much better scavenging power than the standard molecules. In addition, it has been determined by the induced-fit docking method that compound 13 is well-fitted in the active site of the enzymes. ADME studies reveal that the pharmacokinetic and physicochemical properties of all synthesized compounds are within an acceptable range.

Butylated hydroxyanisole: Carcinogenic food additive to be avoided or harmless antioxidant important to protect food supply?

Tumor data from rodent bioassays are used for cancer hazard classification with wide-ranging consequences. This paper presents a case study of the synthetic antioxidant butylated hydroxyanisole (BHA), which IARC classified as Group 2B ("possibly carcinogenic to humans") on the basis of forestomach tumors in rodents following chronic dietary exposure to high levels. IARC later determined that the mechanism by which BHA induces forestomach tumors is not relevant to humans; however, the classification has not been revoked. BHA was listed on California Proposition 65 as a direct consequence of the IARC classification, and there is widespread concern among consumers regarding the safety of BHA driven by the perception that it is a carcinogen. While many regulatory agencies have established safe exposure limits for BHA, the IARC classification and Proposition 65 listing resulted in the addition of BHA to lists of substances banned from children's products and products seeking credentials such as EPA's Safer Choice program, as well as mandatory product labeling. Classifications have consequences that many times pre-empt the ability to conduct an exposure-based risk-based assessment., It is imperative to consider human relevance of both the endpoint and exposure conditions as fundamental to hazard identification.

Comparison of Bioactive Phenolic Compounds and Antioxidant Activities of Different Parts of Taraxacum mongolicum.

Herbs derived from Taraxacum genus have been used as traditional medicines and food supplements in China for hundreds of years. Taraxacum mongolicum is a famous traditional Chinese medicine derived from Taraxacum genus for the treatment of inflammatory disorders and viral infectious diseases. In the present study, the bioactive phenolic chemical profiles and antioxidant activities of flowers, leaves, and roots of Taraxacum mongolicum were investigated. Firstly, a high performance liquid chromatography method combined with segmental monitoring strategy was employed to simultaneously determine six bioactive phenolic compounds in Taraxacum mongolicum samples. Moreover, multivariate statistical analysis, including hierarchical clustering analysis, principal component analysis, and partial least squares discriminant analysis were performed to compare and discriminate different parts of Taraxacum mongolicum based on the quantitative data. The results showed that three phenolic compounds, caftaric acid, caffeic acid, and luteolin, could be regarded as chemical markers for the differences of flowers, leaves, and roots of Taraxacum mongolicum. In parallel, total phenolic contents, total flavonoid contents and antioxidant activities of different parts of Taraxacum mongolicum were also evaluated and compared. It is clear that Taraxacum mongolicum had antioxidant properties, and the antioxidant capacities of different parts of Taraxacum mongolicum in three antioxidant assays showed a similar tendency: Flowers ≈ leaves > roots, which revealed a positive relationship with their total phenolic and flavonoid contents. Furthermore, to find the potential antioxidant components of Taraxacum mongolicum, the latent relationships of the six bioactive phenolic compounds and antioxidant activities of Taraxacum mongolicum were investigated by Pearson correlation analysis. The results indicated caftaric acid and caffeic acid could be the potential antioxidant ingredients of Taraxacum mongolicum. The present work may facilitate better understanding of differences of bioactive phenolic constituents and antioxidant activities of different parts of Taraxacum mongolicum and provide useful information for utilization of this herbal medicine.

Potential Application of Hippophae Rhamnoides in Wheat Bread Production.

Sea buckthorn (Hippophae rhamnoides) berries are well known for their content in bioactive compounds, high acidity, bright yellow color, pleasant taste and odor, thus their addition in a basic food such as bread could be an opportunity for modern food producers. The aim of the present research was to investigate the characteristics and the effects of the berry' flour added in wheat bread (in concentration of 1%, 3% and 5%) on sensory, physicochemical and antioxidant properties, and also bread shelf life. Berry flour contained total polyphenols-1467 mg gallic acid equivalents (GAE)/100 g, of which flavonoids-555 mg GAE/100 g, cinnamic acids-425 mg caffeic acid equivalents (CAE)/100 g, flavonols-668 mg quercetin equivalents (QE)/100 g. The main identified phenolics were catechin, hyperoside, chlorogenic acid, cis- and trans-resveratrol, ferulic and protocatechuic acids, procyanidins B1 and B2, epicatechin, gallic acid, quercetin, p- and m-hydroxybenzoic acids. The antioxidant activity was 7.64 mmol TE/100 g, and carotenoids content 34.93 ± 1.3 mg/100 g. The addition of berry flour increased the antioxidant activity of bread and the shelf life up to 120 h by inhibiting the development of rope spoilage. The obtained results recommend the addition of 1% Hippophae rhamnoides berry flour in wheat bread, in order to obtain a product enriched in health-promoting biomolecules, with better sensorial and antioxidant properties and longer shelf life.

Phenolic Compounds, Antioxidant Activities, and Inhibitory Effects on Digestive Enzymes of Different Cultivars of Okra (Abelmoschus esculentus).

In this study, the phenolic profiles and bioactivities of five representative cultivars of okra collected in China were investigated. Noticeable variations of phenolic compounds and their bioactivities were observed among these different cultivars of okra. The contents of total flavonoids (TFC) in "Shuiguo", "Kalong 8", "Kalong 3", "Wufu", and "Royal red" ranged from 1.75 to 3.39 mg RE/g DW, of which "Shuiguo" showed the highest TFC. Moreover, five individual phenolic compounds were found in okra by high performance liquid chromatography analysis, including isoquercitrin, protocatechuic acid, quercetin-3-O-gentiobioside, quercetin, and rutin, while isoquercitrin and quercetin-3-O-gentiobioside were detected as the main phenolic compounds in okra. Moreover, all tested okra exhibited significant antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, 2,2'-azino-bis (3-ethylenzthiazoline-6-sulphonic acid) radical scavenging capacity, and ferric reducing antioxidant power) and inhibitory effects on digestive enzymes (lipase, α-glucosidase, and α-amylase). Indeed, "Shuiguo" exhibited much better antioxidant activities and inhibitory activities on digestive enzymes, which might be attributed to its high TFC. Results suggested that okra, especially "Shuiguo", could be developed as natural antioxidants and inhibitors against hyperlipidemia and hyperglycemia in the fields of functional foods and pharmaceuticals, which could meet the increasing demand for high-quality okra with health-promoting properties in China.

Effect of Different Durations of Solid-Phase Fermentation for Fireweed (Chamerion angustifolium (L.) Holub) Leaves on the Content of Polyphenols and Antioxidant Activity In Vitro.

Fireweed has recently been recognized as a plant with high antioxidant potential and phenolic content. Its leaves can be fermented to prepare an infusion with ideal antioxidant activity. The aim of this study was to investigate and to determine the influence of solid-phase fermentation of different durations on the variation of polyphenols in the leaves of fireweed. Laboratory experiments were conducted in 2017-2018. The leaves of fireweed, naturally growing, were fermented for different periods of time: not fermented (control) and fermented for 24 and 48 h. The evaluation of polyphenols and antioxidant activity in leaves was performed using high- performance liquid chromatography (HPLC). Additionally, principal component analysis was used to characterize differences in bioactive compounds between fireweed samples fermented at different durations. Solid-phase fermented leaves were characterized by higher contents of oenothein B, quercetin and benzoic acid but had lower contents of quercetin-3-O-rutinoside, luteolin and chlorogenic and gallic acids. Antioxidant activity in short- (24 h) and long-term (48 h) fermentation (compared to control) gave the highest level of regression in 2017, but in 2018 the effect was observed only with short-term fermentation and control. In conclusion, solid-phase fermentation can be used to modulate biologically active compounds in fireweed leaves.