Nitrite Scavenging Research Articles

Nitrite scavenging activities and reducing power capacities of ethanolic extracts of some fruits and vegetables

The use of fruits and vegetables for therapeutic purposes has been continuing for centuries. Now-a-days, fruits and vegetables are increasingly used as alternative medicines. The antioxidant activities of some fruits and vegetables used in the present study were determined by nitrite scavenging and reduction power experiments. Antioxidant capacity increased with increasing concentration. The highest nitrite scavenging activity and inhibitory power were observed in garlic extract. The least nitrite scavenging activity and reducing power were found in white grape and kiwi extracts. It was concluded that garlic extract which had the highest nitrite scavenging capacity and reducing power may be an appropriate additive in drugs and other pharmaceuticals intended for medical purposes. Bangladesh J. Bot. 53(3): 619-625, 2024 (September)

Optimization of the ultrasonic-assisted enzymatic extraction of polysaccharides from Dendrobium offcinale Kimura et Migo and bioactivity study

ABSTRACT Ultrasonic-assisted enzymatic extraction (UAEE) technology was employed to extract the polysaccharides from Dendrobium offcinale Kimura et Migo (D. offcinale). The extraction conditions were optimized by central composite design (CCD) found in the response surface methodology (RSM). The polysaccharide yield (34.05 ± 1.03%) was well matched with the predicted value, as obtained under the optimum parameters: enzyme activity of 2040 U/g, a liquid-solid ratio of 71 mL/g, and a time of 84 min. Compared to other extraction methods, UAEE was able to yield D. offcinale polysaccharide (DOP) highly efficiently in a shorter extraction time period and at a lower extraction temperature. The extracted polysaccharide (DOPUAEE) showcased a better nitrite scavenging ability, a high antioxidant activity, and more potency in inhibiting α-glucosidase, expanding its versatility in food applications.

Anti-oxidant and Anti-inflammatory Effects of Ethanol Extract from Polygala sibirica L. var megalopha Fr. on Lipopolysaccharide-Stimulated RAW264.7 Cells.

To investigate the anti-oxidant and anti-inflammatory effects of ethanol extract of Polygala sibirica L. var megalopha Fr. (EEP) on RAW264.7 mouse macrophages. RAW264.7 cells were pretreated with 0-200 µg/mL EEP or vehicle for 2 h prior to exposure to 1 µg/mL lipopolysaccharide (LPS) for 24 h. Nitric oxide (NO) and prostaglandin (PGE2) production were determined by Griess reagent and enzyme-linked immunosorbent assay (ELISA), respectively. The mRNA levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor α (TNF-α), interleukin-1beta (IL-1β), and IL-6 were determined using reverse transcription polymerase chain reaction (RT-PCR). Western blot assay was used to determine the protein expressions of iNOS, COX-2, phosphorylation of extracellular regulated protein kinases (ERK1/2), c-Jun N-terminal kinase (JNK), inhibitory subunit of nuclear factor Kappa B alpha (Iκ B-α) and p38. Immunofluorescence was used to observe the nuclear expression of nuclear factor-κ B p65 (NF-κ B p65). Additionally, the anti-oxidant potential of EEP was evaluated by reactive oxygen species (ROS) production and the activities of catalase (CAT) and superoxide dismutase (SOD). The 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), superoxide anion (O2-) radical and nitrite scavenging activity were also measured. The total polyphenol and flavonoid contents of EEP were 23.50±2.16 mg gallic acid equivalent/100 g and 43.78±3.81 mg rutin equivalent/100 g. With EEP treatment (100 and 150 µg/mL), there was a notable decrease in NO and PGE2 production induced by LPS in RAW264.7 cells by downregulation of iNOS and COX-2 mRNA and protein expressions (P<0.01 or P<0.05). Furthermore, with EEP treatment (150 µg/mL), there was a decrease in the mRNA expression levels of TNF-α, IL-1β and IL-6, as well as in the phosphorylation of ERK, JNK and p38 mitogen-activated protein kinase (MAPK, P<0.01 or P<0.05), by blocking the nuclear translocation of NF-κ B p65 in LPS-stimulated cells. In addition, EEP (100 and 150 µg/mL) led to an increase in the anti-oxidant enzymes activity of SOD and CAT, with a concomitant decrease in ROS production (P<0.01 or P<0.05). EEP also indicated the DPPH, OH, O2- radical and nitrite scavenging activity. EEP inhibited inflammatory responses in activated macrophages through blocking MAPK/NF-κ B pathway and protected against oxidative stress.

Preparation and characterization of inclusion complex of Myristica fragrans Houtt. (nutmeg) essential oil with 2-hydroxypropyl-β-cyclodextrin

Nutmeg essential oil (NEO) is a natural condimentwith versatile biological activities. However, the application of NEO in food has several limitations due to its poor stability and low aqueous solubility. To overcome the shortcomings, this paper focused on the preparation of the inclusion complex (IC) of NEO with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) by the coprecipitation method. The optimal condition was inclusion temperature 36 ℃, time 247 min, stirring speed 520 r/min, and wall-core ratio 12:1, resulting in a recovery of 80.63%. The formation of IC was verified by various methods such as scanning electron microscopy, Fourier transform infrared spectroscopy and nuclear magnetic resonance. The improvement of thermal stability, antioxidant, and nitrite scavenging activities of NEO after encapsulation was proven. Moreover, the controlled release of NEO from IC can be implemented by regulating the temperature and relative humidity. Overall, NEO/HP-β-CD IC has great application potential in food industries.

Effect mechanism of different drying methods on the quality and browning for daylily

The influence of various drying methods, namely hot-air drying (HAD), heat pump drying (HPD), freeze-drying (FD), and microwave freeze drying (MFD), on the structural characterization and browning substrates of daylily was investigated. The chemical structure as determined by Fourier Transform infrared spectroscopy of the products from different drying methods were similar and the microphysical structure (microstructures and texture) were significantly different. High-quality daylily products with a bright appearance and a lower degree of browning were produced by FD and MFD. Higher contents of browning substrates (phenolic acid, total flavonoids, and total phenols) were found in products with lower browning (color, browning degree and Maillard fluorescent compounds). FD products kept the highest contents of gallic acid (27.39 mg/100 g), chlorogenic acid (35.92 mg/100 g), and quercetin (15.03 mg/100 g), and had a high nitrite scavenging activity. MFD products kept the highest contents of catechin (144.90 mg/100 g), rutin (71.5 mg/100 g), and kaempferol (33.87 mg/100 g). The results showed that the final products produced by FD and MFD had superior quality than those produced with HAD and HPD. FD and MFD are suitable for daylily powder with high nutritional value and HAD and HPD are suitable for large-scale production and affordable dried daylily products.

Effects of seed pre-soaking on bioactive phytochemical levels of wheat and barley microgreens grown under hydroponics &lt;em&gt;versus&lt;/em&gt; organic soil conditions

This study was conducted to examine the effects of seed presoaking on bioactive phytochemicals in barley and wheat microgreens grown under two different growing media, i.e., hydroponics and organic soil. Microgreens were cultivated for 12 days in a plant growth chamber consistent with the following: light-dark interval (12/12 hours), light-dark temperature (20/15°C), light intensity (150 μmol‧m–2‧s–1), and relative humidity (60%). Both wheat and barley microgreens grown in organic soil from presoaked seeds showed increased levels of bioactive compounds, especially carotenoids, flavonoids, phenolics, total vitamin C, and anthocyanins. Antioxidant activities [2,2-diphenyl-1-picrylhydrazyl, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, nitrite scavenging activity, and superoxide dismutase (SOD)-like activity] and antioxidant enzymes (catalase activity, glutathione reductase, and guaiacol peroxidase activity) were highest in both barley and wheat microgreens grown in organic soil from pre-soaked seeds.

Effects of Hanwoo (Korean cattle) manure as organic fertilizer on plant growth, feed quality, and soil bacterial community.

The development of organic manure from livestock excreta is a useful source for sustainable crop production in environment-friendly agriculture. Organic manure increases soil microbial activity and organic matter (OM) supply. The excessive use of chemical fertilizers (CFs) leads to air and water pollution caused by toxic chemicals and gases, and soil quality degradation via nutrient imbalance due to supplying specific chemical components. Thus, the use of organic manure will serve as a long-term supply of various nutrients in soil via OM decomposition reaction as well as the maintenance of environment. In this study, we aimed to analyze the diverse effects of Hanwoo manure (HM) on plant growth, feed quality, and soil bacterial communities in comparison with CFs, commercial poultry manure (CM), and the combined use of chemical fertilizer and Hanwoo manure (HM+CF). We analyzed the contents of crude matter (protein, fat, fiber, and ash), P, acid detergent fiber (ADF), and neutral detergent fiber (NDF) through feed quality analysis, and the contents or activities of total phenol, total flavonoid, ABTS, nitrite scavenging, and reducing power via the antioxidant assay. Furthermore, the soil microbial communities were determined using 16S rRNA sequencing. We compared the soil bacteria among different soil samples by using amplicon sequence variant (ASV) analysis. We observed increased OM in the soil of the HM group compared to that of the CF and non-treated groups over a period of two years. Moreover, HM+CF treatment enormously improved plant growth. Organic manure, especially HM, caused an increase in the content of crude ash and phosphorus in plants. There were no significant differences in total polyphenol, total flavonoid, ABTS, nitrite scavenging, and reducing power in plants between HM and CF groups. Finally, we detected 13 soil bacteria (Acidibacter, Algisphaera, Cystobacter, Microvirga, Ohtaekwangia, Panacagrimonas, Pseudarthrobacter, Reryanella, Rhodoligotrophos, Solirubrobacter, Stenotrophobacter, Tellurimicrobium, and Thermomarinilinea) that were considerably correlated with OM and available phosphorus, and three considerably correlated bacteria were specifically distributed in CF or organic manure. The results suggest that HM is a valuable source of organic manure that can replace CF for sustainable crop production.

Comparative Analysis of Roots from Vicatia thibetica de Boiss and Angelica sinensis Based on Chemical Composition, Antioxidant, Nitrite-Scavenging and Enzyme Inhibition Activities.

Radix Vicatia thibetica de Boiss (RVT) is locally known as "Xigui" or "Dujiao-danggui" in Tibetan medicine and is often used as a substitute for Radix Angelica sinensis (RAS) in daily nourishing diets and clinical applications. In this study, we determined and compared the contents of polysaccharides, total coumarins, ferulic acid, total phenols, total flavonoids, chlorogenic acid, protein, and amino acids, and the composition of volatile oil in RVT and RAS. Biological activities, including antioxidants, scavenging of nitrite, inhibition of tyrosinase, thrombin, and coagulation FXa, were comparatively evaluated. Results showed that RVT contains more polysaccharides, phenols, flavonoids, proteins, glutamic acid, and lysine as compared to RAS. Among volatile compounds, 14 species are similar, and 20 species are different in RVT and RAS. Overall, among volatile compounds, the content of 3-N-Butylphthalide was higher, whereas the content of ligustilide was lower in RVT volatile oil. A significant difference was reported in the bioactivity of RVT and RAS. The biological activity of RVT had higher antioxidant, nitrite scavenging, and tyrosinase inhibitory activities, whereas it showed much lower thrombin and FXa inhibitory activities. Correlation analysis showed that the antioxidant, nitrite scavenging, and tyrosinase inhibitory activities were related to the phenol and flavonoid content, whereas the thrombin and FXa inhibitory activities were related to ferulic acid and volatile oil content. This study presents a comparative analysis of RAS and RVT's chemical compositions of antioxidant, nitrite-scavenging, inhibition of tyrosinase, thrombin, and coagulation FXa activities. It was found that both RVT and RAS have their unique advantages, and RVT has the potential to be utilized as functional foods, cosmetics, and medical products.

Nitrite scavenging and lipid peroxidation inhibitory effects of solvent fractions from Phragmites communis rhizome extract

Nitrite scavenging and lipid peroxidation inhibitory effects of solvent fractions from <i>Phragmites communis</i> rhizome extract

Functional components in Portulaca oleracea explored to scavenge nitrite and block nitrosamines in tobacco using affinity ultrafiltration with Nitrate Reductase

Tobacco-Specific Nitrosamines (TSNAs) are a class of common carcinogens that are widely present in cigarette products and smoke, which seriously affect the health of smokers and vastly restrict the safety of tobacco products. In our present research, the effects of Portulaca oleracea on nitrite scavenging and nitrosamine formation were evaluated through in vitro and tobacco field experiments. Further, four compounds Ferulic Acid O-Glucoside, Ellagic Acid, 13:4 + 4O Fatty Acyl Hexoside, and Feruloylmalic Acid were tentatively screened as potential Nitrate Reductase (NR) ligands by affinity ultrafiltration HPLC-MS. Molecular docking was then carried out to further verify the inhibitory activities of these potential ligands and elucidate their interaction mechanisms with NR. The results showed that P. oleracea exhibited substantial abilities in scavenging nitrite and blocking the formation of nitrosamines, which was mainly attributed to its abundant reductive components, especially its phenolics. In conclusion, the current study provided new insight into new strategies to reduce tobacco toxicity based on natural extracts, which is of great value to the tobacco industry.

Assessment of a Diverse Array of Nitrite Scavengers in Solution and Solid State: A Study of Inhibitory Effect on the Formation of Alkyl-Aryl and Dialkyl N-Nitrosamine Derivatives

The ubiquitous presence of mutagenic and potentially carcinogenic N-nitrosamine impurities in medicines has become a major issue in the pharmaceutical industry in recent years. Rigorous mitigation strategies to limit their amount in drug products are, therefore, needed. The removal of nitrite, which is a prerequisite reagent for the N-nitrosation of amines, has been acknowledged as one of the most promising strategies. We have conducted an extensive literature search to identify nineteen structurally diverse nitrite scavengers and screened their activity experimentally under pharmaceutically relevant conditions. In the screening phase, we have identified six compounds that proved to have the best nitrite scavenging properties: ascorbic acid (vitamin C), sodium ascorbate, maltol, propyl gallate, para-aminobenzoic acid (PABA), and l-cysteine. These were selected for investigation as inhibitors of the formation of N-methyl-N-nitrosoaniline (NMA) from N-methylaniline and N-nitroso-N’-phenylpiperazine (NPP) from N-phenylpiperazine in both solution and model tablets. Much faster kinetics of NMA formation compared to NPP was observed, but the former was less stable at high temperatures. Vitamin C, PABA, and l-cysteine were recognized as the most effective inhibitors under most studied conditions. The nitrite scavenging activity does not directly translate into N-nitrosation inhibitory effectiveness, indicating other reaction pathways may take place. The study presents an important contribution to identifying physiologically acceptable chemicals that could be added to drugs to prevent N-nitrosation during manufacture and storage.

Specific Denitrifying and Dissimilatory Nitrate Reduction to Ammonium Bacteria Assisted the Recovery of Anammox Community From Nitrite Inhibition.

The anaerobic ammonium oxidation (anammox) by autotrophic anaerobic ammonia-oxidizing bacteria (AnAOB) is a biological process used to remove reactive nitrogen from wastewater. It has been repeatedly reported that elevated nitrite concentrations can severely inhibit the growth of AnAOB, which renders the anammox process challenging for industrial-scale applications. Both denitrifying (DN) and dissimilatory nitrate reduction to ammonium (DNRA) bacteria can potentially consume excess nitrite in an anammox system to prevent its inhibitory effect on AnAOB. However, metabolic interactions among DN, DNRA, and AnAOB bacteria under elevated nitrite conditions remain to be elucidated at metabolic resolutions. In this study, a laboratory-scale anammox bioreactor was used to conduct an investigation of the microbial shift and functional interactions of AnAOB, DN, and DNRA bacteria during a long-term nitrite inhibition to eventual self-recovery episode. The relative abundance of AnAOB first decreased due to high nitrite concentration, which lowered the system’s nitrogen removal efficiency, but then recovered automatically without any external interference. Based on the relative abundance variations of genomes in the inhibition, adaptation, and recovery periods, we found that DN and DNRA bacteria could be divided into three niche groups: type I (types Ia and Ib) that includes mainly DN bacteria and type II and type III that include primarily DNRA bacteria. Type Ia and type II bacteria outcompeted other bacteria in the inhibition and adaptation periods, respectively. They were recognized as potential nitrite scavengers at high nitrite concentrations, contributing to stabilizing the nitrite concentration and the eventual recovery of the anammox system. These findings shed light on the potential engineering solutions to maintain a robust and efficient industrial-scale anammox process.

In vitro Angiotensin Converting Enzyme Inhibitory and Antioxidant Activities of Some Sulfur Compounds

The angiotensin converting enzyme (ACE) catalyzes the conversion of angiotensin I to a key vasoconstrictor angiotensin II in renin-angiotensin system (RAS), thus playing an important role in both regulating blood pressure and maintaining fluid balance through RAS. Free radicals are continuously produced in the biological system. Therefore, organisms need both exogenous and endogenous antioxidants to guard against the damage caused by these free radicals. In this way, they prevent the occurrence of numerous diseases via protecting cellular components and biomolecules. The aim of the current study was to investigate the ACE inhibitory and antioxidant activities of sulfur compounds. The ACE inhibitory and antioxidant activities of all sulfur compounds increased in a concentration-dependent manner. Among these compounds, methionine had the highest ACE inhibitory and antioxidant activityes based on reducing power, DPPH radical scavenging and ORAC methods. Cystine had the highest ABTS radical scavenging, FRAP and nitrite scavenging activities. However, S-benzyl cysteine and S-phenyl cysteine exhibited the lowest ACE inhibitory and antioxidant activities, respectively. These outcomes indicate that sulfur compounds have both ACE inhibitory and antioxidant activities and may serve as gateways for research toward understanding the beneficial pharmacological effects of sulfur compounds against cell damage caused by oxidative stress.

Antilipase, antiacetylcholinesterase and antioxidant activities of Moringa oleifera extracts

Pancreatic lipase is critical for the catabolism of lipids in the intestine, making it a prime target for obesity management. Acetylcholinesterase is an important enzyme that hydrolyses the neurotransmitter acetylcholine. It inhibition is paramount in enhancing systemic acetylcholine level. Side effects of conventional drugs lead to continued search for alternative anti-obesity and anticholinesterase agents. The present study assessed lipase and acetylcholinesterase inhibition, as well as antioxidant activity of Moringa oleifera extracts. The inhibitory activities of the extracts on lipase and acetylcholinesterase were dose dependent. Aqueous leaf extract (IC50 = 3.26 ± 0.26 mg/ml) and hexane root extract (IC50 = 0.08 ± 0.00 mg/ml) exhibited the highest antilipase and antiacetylcholinesterase activity respectively. Aqueous extracts of root and leaf (IC50 of 1.43 ± 0.03mg/ml and 1.86 ± 0.10 mg/ml respectively) had the highest N, N-dimethyl-p-phenylene diamine dihydrochloride radical scavenging activity, while ethyl acetate leaf extract had the highest nitrite scavenging activity (IC50 = 2.20 ± 0.06 mg/ml). Compared to other extracts, methanol leaf extract exhibited the highest ferric reducing power. These findings suggest that M. oleifera possess promising antilipase, antiacetylcholinesterase and antioxidant potentials. Therefore, may be employed as food additive for the management of obesity, Alzheimer and other degenerative diseases.

Free Radical Scavenging Capacities and Alleviating Actions of Polysaccharides Extract of Termitomyces le-testui on Methylprednisolone-Induced Immunodepression in Rats.

Background Natural products have been said to show immunomodulatory and antioxidant activities. The research study was aimed to assess the immunomodulatory and free radical scavenging activities of crude polysaccharide from dry mushroom fruiting bodies of Termitomyces le-testui. Materials and Methods Hot water extract of polysaccharide extract of T. le-testui was prepared and tested in white albino Wister rats for its immunomodulatory activities effect on methylprednisolone-immunosuppressed animals. In addition, the radical scavenging activity of the polysaccharide was evaluated using nitrite and hydrogen peroxide. Results The result of the study showed that the polysaccharide T. le-testui increases the phagocytic index, energy metabolism of macrophages, spleen index, and nitric oxide in a concentration-dependent manner in immunosuppressed animals. Also, it was observed that the extract increased dose-dependent total oxidative stress and thymus index. Finally, the crude polysaccharide-rich extract showed nitrite and hydrogen peroxide scavenging activity in a concentration-dependent manner. Conclusion Polysaccharide-rich extract possesses immunomodulatory and antioxidant properties.

Quality properties and bioactivities of American cookies with coffee extract residues

In this study, American cookies with coffee extract residues (blending (BL), Ethiopia Yirgacheffe (EY), or Guatemala strictly hard bean Antigua (GA)) were produced, and their quality properties and bioactivities were compared with cookie without those (CCO). The density and pH of cookie doughs, and proximate composition, spread ratio, loss rate, hardness, and color value of the cookies with coffee extract residues (CERs) were acceptable compared to CCO. Total phenolic and flavonoid contents, and antioxidant activity were higher in the water and ethanol extracts of the cookies with CERs than in those of CCO. The nitrite scavenging activity was also higher in the water extracts of the cookies with CERs than in that of CCO. The lipase inhibitory activities were higher only in the CBL for ethanol extracts relative to the CCO. Conclusively, the cookies with CERs showed no deterioration in the quality properties relative to CCO, whereas the bioactivities were enhanced. Thus, the CERs that are otherwise discarded as food waste may be used in the production of cookies, not only to reduce food waste and protect the environment, but also to produce foods with enhanced functionality and provide an increased variety of foods to consumers.

Evaluation of Quality Characteristics of Low-Nitrite Pork Sausages with Paprika Oleoresin Solution during Refrigerated Storage.

The objective of this study was to evaluate quality characteristics of pork emulsified-sausage (ES) containing paprika oleoresin solution (POS) as a replacement for sodium nitrite (NaNO2) during refrigerated storage. ESs were prepared with four treatments: 1) REF, 150 ppm NaNO2; 2) CTL, 75 ppm NaNO2; 3) TRT1, 75 ppm NaNO2+0.1% POS (1% paprika oleoresin+99% sunflower seed oil); and 4) TRT2, 75 ppm NaNO2+0.1% POS (5% paprika oleoresin+95% sunflower seed oil). The addition of POS into ES increased redness and yellowness but decreased lightness (p<0.05). TRT1 and TRT2 had higher redness and yellowness than CTL (p<0.05). TRT1 and TRT2 had lower total plate counts (Log CFU/g) than CTL due to antimicrobial activity of POS, regardless of its levels (p<0.05). Residual nitrite decreased with increasing storage time for all treatments. TRT2 had lower residual nitrite due to nitrite scavenging activity of POS (p<0.05). CTL had the highest thiobarbituric acid reactant substances (TBARS) among all treatments during storage. The addition of POS into ES showed nitrite scavenging activity during refrigerated storage. In conclusion, antimicrobial and antioxidant activities of the ES with a combination of POS and 75 ppm NaNO2 were similar to those of REF (150 ppm NaNO2), and improved color development of redness value. Therefore, the addition of POS could decrease the amount of nitrite in ESs, leading to healthier meat products.

Effect of gamma-ray, electron-beam, and X-ray irradiation on antioxidant activity of mugwort extracts

The objective of this study was to compare the effect of radiation sources (gamma-rays, electron-beams, and X-rays) and dose levels (0, 2, 6, and 10 kGy) on the phytochemical profile of mugwort extracts. As the irradiation dose increased, antioxidant contents (total phenol and flavonoid contents) and antioxidant activities (DPPH radical scavenging activity, ferric reducing power ability, and nitrite scavenging capacity) increased, irrespective of the radiation source used. Interactions effects between the irradiation source and dose level in all the experiments of mugwort extracts were observed (P < 0.05), except for the nitrite scavenging capacity. Notably, gamma-ray irradiation led to an effective increase in not only the antioxidant contents but also the activities of mugwort extracts, followed by X-ray and electron-beam irradiation at doses up to 10 kGy (P < 0.05). Our findings suggest that the optimum irradiation source for boosting the physiological activity of mugwort extracts is gamma-rays. Therefore, enhanced activities of mugwort extracts through irradiation could be applied to various industries, especially as a natural antioxidant source in foodstuffs.

Anti-Inflammatory, Barrier-Protective, and Antiwrinkle Properties of Agastache rugosa Kuntze in Human Epidermal Keratinocytes.

This work aimed to assess the skin-beneficial properties of Agastache rugosa Kuntze, an herbal medication used to treat different types of disorders in traditional folk medicine. The total phenolic compounds and total antiradical, nitrite scavenging, superoxide scavenging, antielastase, and antihyaluronidase activities of a hot water extract of A. rugosa Kuntze leaves (ARE) were spectrophotometrically determined. Intracellular reactive oxygen species (ROS) was fluorometrically quantitated using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA). Inducible nitric oxide synthase (iNOS) and filaggrin were evaluated using Western analysis. Real-time quantitative RT-PCR was used to measure filaggrin mRNA. Caspase-14 activity was determined using a fluorogenic substrate. ARE contained the total phenolic content of 38.9 mg gallic acid equivalent/g extract and exhibited 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide radical, and nitrite scavenging activities with the SC50 values of 2.9, 1.4, and 1.7 mg/mL, respectively. ARE exerted suppressive activities on nitric oxide (NO) and ROS levels elevated by lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α) in HaCaT keratinocytes. It attenuated the LPS-stimulated expression of iNOS. ARE augmented the UV-B-reduced filaggrin expression on both protein and mRNA levels and was capable of upregulating the UV-B-reduced caspase-14 activity. ARE inhibited in vitro elastase and hyaluronidase activities associated with the wrinkling process. ARE, at the concentrations used, did not interfere with the viability of HaCaT keratinocytes. These findings preliminarily imply that the leaves of A. rugosa possess desirable cosmetic potentials, such as anti-inflammatory, barrier protective, and antiwrinkle activities, which infers their skin healing potentials.

Nitrite Scavenging and Inhibition of N-Nitrosamines Formation by Phenolic Extracts From Diospyros lotus L. Leaves and Active Ingredients

Diospyros lotus L. leaves are used as a functional tea and folk medicine in several Asian countries. This study aimed to evaluate the effects of phenolic extracts of the leaves on scavenging nitrite and inhibiting N-nitrosamines (NAs) formation and to determine the active ingredients responsible for these effects. Of the 7 fractions (Fr1-Fr7) prepared from the extract of D. lotus leaves, Fr5 contained the highest phenolic content and exhibited the strongest activity. Five active ingredients of Fr5 were discovered, and 4 of them were identified as myricitrin (Mytr), myricetin (Myt), myricetin-3- O-β-d-glucoside (Myt-Glc), and myricetin-3- O-β-d-galactoside (Myt-Gal). The content of Mytr was much higher than those of the other 3 ingredients, both in Fr5 and extracts of D. lotus leaves. Finally, Mytr and Myt were proved to have stronger activities by the 1,1-diphenyl-2-trinitrophenyl hydrazine scavenging, nitrite scavenging, and inhibition of NAs formation assays. These results indicated that Mytr was the main active ingredient of D. lotus leaves. Myt, Mytr, and Fr5 from the leaves could be used as natural agents for antioxidant, nitrite scavenging, and inhibition of NAs formation in food and the human body.