A Redox Mediator-Free Highly Selective and Sensitive Electrochemical Aptasensor for Patulin Mycotoxin Detection in Apple Juice Using Ni-NiO Pseudocapacitive Nanomaterials.

Pseudocapacitive nanomaterials have recently gained significant attention in electrochemical biosensors due to their rapid response, long cycle life, high surface area, biomolecule compatibility, and superior energy storage capabilities. In our study, we introduce the potential of using Ni-NiO nanofilm's pseudocapacitive traits as transducer signals in electrochemical aptasensors. Capitalizing on the innate affinity between histidine and nickel, we immobilized histidine-tagged streptavidin (HTS) onto Ni-NiO-modified electrodes. Additionally, we employed a biolayer interferometry-based SELEX to generate biotinylated patulin aptamers. These aptamers, when placed on Ni-NiO-HTS surfaces, make a suitable biosensing platform for rapid patulin mycotoxin detection in apple juice using electrochemical amperometry in microseconds. The novelty lies in optimizing pseudocapacitive nanomaterials structurally and electrochemically, offering the potential for redox mediator-free electrochemical aptasensors. Proof-of-concept is conducted by applying this surface for the ultrasensitive detection of a model analyte, patulin mycotoxin. The aptamer-functionalized bioelectrode showed an excellent linear response (10-106 fg/mL) and an impressive detection limit (1.65 fg/mL, +3σ of blank signal). Furthermore, reproducibility tests yielded a low relative standard deviation of 0.51%, indicating the good performance of the developed biosensor. Real sample analysis in freshly prepared apple juice revealed no significant difference (P < 0.05) in current intensity between spiked and real samples. The sensor interface maintained excellent stability for up to 2 weeks (signal retention 96.45%). The excellent selectivity, stability, and sensitivity of the electrochemical aptasensor exemplify the potential for using nickel-based pseudocapacitive nanomaterials for a wide variety of electrochemical sensing applications.

Correction: Graphene oxide-mediated fluorescence turn-on GO-FAM-FRET aptasensor for detection of sterigmatocystin.

Correction for 'Graphene oxide-mediated fluorescence turn-on GO-FAM-FRET aptasensor for detection of sterigmatocystin' by Pravin Savata Gade et al., Anal. Methods, 2022, 14, 3890-3897, DOI: https://doi.org/10.1039/D2AY01405J.

Green Downstream Processing Method for Xylooligosaccharide Purification and Assessment of Its Prebiotic Properties.

Xylooligosaccharides (XOS) obtained from lignocellulosic biomass after autohydrolysis primarily consist of lignin-derived impurities and autogenerated inhibitors like furfural, hydroxymethylfurfural, and acetic acid. In this study, graphene oxide-mediated purification (GOMP), a novel and environmentally friendly downstream processing method, was developed for the purification of XOS from hydrolysate obtained after ozone-assisted autohydrolysis of wheat bran. GOMP resulted in appreciable recovery of total XOS from the hydrolysate (73.87 ± 4.25%, DP2-6) with near complete removal of autogenerated inhibitors (furfural 85.42%, HMF 87.38%, and acetic acid 84.0%). Recovery of XOS by GOMP was higher than the conventional membrane purification technique (44.07 ± 0.92%) and activated charcoal treatment (72.76 ± 0.84%) along with comparatively higher removal of inhibitor compounds. GOMP results in the selective adsorption of inhibitors on the graphene oxide matrix from the XOS-rich hydrolysate, resulting in its purification and concentration. The prebiotic function of the obtained XOS fractions (DP2-4.48%, DP3-39.69%, DP4-36.13%, DP5-8.38%, and DP6-13.10%) was evaluated, indicating the growth stimulation of tested probiotic cultures and differential utilization of XOS oligomers DP3 and DP4 and complete consumption of DP2, DP5, and DP6 along with short-chain fatty acids as a major fermentation product. These findings suggest that GOMP, which employs a common substance (i.e., graphene oxide) used in water treatment, exhibits potential as an efficient and economically viable single-step methodology for XOS purification.

Rational Truncation of Aptamer for Ultrasensitive Aptasensing of Chloramphenicol: Studies Using Bio-Layer Interferometry.

Aptamers are an excellent choice for the selective detection of small molecules. However, the previously reported aptamer for chloramphenicol suffers from low affinity, probably as a result of steric hindrance due to its bulky nature (80 nucleotides) leading to lower sensitivity in analytical assays. The present work was aimed at improving this binding affinity by truncating the aptamer without compromising its stability and three-dimensional folding. Shorter aptamer sequences were designed by systematically removing bases from each or both ends of the original aptamer. Thermodynamic factors were evaluated computationally to provide insight into the stability and folding patterns of the modified aptamers. Binding affinities were evaluated using bio-layer interferometry. Among the eleven sequences generated, one aptamer was selected based on its low dissociation constant, length, and regression of model fitting with association and dissociation curves. The dissociation constant could be lowered by 86.93% by truncating 30 bases from the 3' end of the previously reported aptamer. The selected aptamer was used for the detection of chloramphenicol in honey samples, based on a visible color change upon the aggregation of gold nanospheres caused by aptamer desorption. The detection limit could be reduced 32.87 times (1.673 pg mL-1) using the modified length aptamer, indicating its improved affinity as well as its suitability in real-sample analysis for the ultrasensitive detection of chloramphenicol.

Graphene oxide-mediated fluorescence turn-on GO-FAM-FRET aptasensor for detection of sterigmatocystin.

Sterigmatocystin (STC) is a toxic fungal secondary metabolite recognized by the FAO and WHO as a genotoxic and carcinogenic substance. STC contaminates several foods and feed commodities, posing a health risk to humans. The present study proposes to develop a graphene oxide-mediated aptasensor platform for the one-step detection of STC. In this study, DNA aptamers were generated against STC by using a target immobilization-free graphene oxide (GO)-SELEX protocol. The champion aptamers were subjected to in silico maturation using a genetic algorithm to improve binding affinity. Further, MSA-C6 and STC interactions were characterized by MD simulation, bio-layer interferometry (KD 27.9 nM) and flow cytometry. GO was immobilized on a polypropylene surface and functionalized with FAM labelled MSA-C6 to develop a simple one-step fluorescence turn-on aptasensor. The linear detection range of the aptasensor was found to be 80-720 ppb with LOD 23.56 ± 4.93 ppb and LOQ 132.43 ± 3.25 ppb. Insignificant interference of salts and detergents as well as negligible cross-reactivity with other structurally similar mycotoxins were observed. Recovery studies in simulated contaminated samples indicated appreciable recoveries (71-89%) using aptasensing assay. The results of the study indicate the successful development of a simple one-step detection platform for STC, useful for the measurement and monitoring of samples for the presence of STC. It also reports a high-affinity aptamer, which can be exploited in other sensing platforms.

Bio-Layer Interferometry-Based SELEX and Label-Free Detection of Patulin Using Generated Aptamer.

This study reports a novel bio-layer interferometry (BLI)-based SELEX for generation of high affinity aptamers against patulin. Unlike conventional SELEX, the present method enabled real-time monitoring of increasing affinity of the oligonucleotides to the toxin. After seven rounds of selection cycles, the enriched pool of aptamers was characterized by cloning and sequencing and clustered into two families based on similarity. Two sequences, PAT C3 and PAT C4, each belonging to different clades, were further evaluated for their binding affinity. SPR studies determined the dissociation constants (KD) of 8.2 × 10-8 and 1.9 × 10-7 M for aptamer PAT C3 and PAT C4, respectively. The highest affinity PAT C3 aptamer was used to develop a patulin BLI aptasensor, which indicated a linear detection range from 0.045 to 100 ng/mL [limit of detection (LOD) = 0.173 ng/mL; limit of quantification (LOQ) = 0.526 ng/mL]. The aptasensor displayed no cross-reactivity with its structural analogue isopatulin or any of the other mycotoxin groups tested. Spiking studies in simulated apple juice samples showed recoveries in the range of 82.11 to 100.23%, indicating good sensor performance. The study is the first report of BLI-based SELEX for a non-protein toxin, which resulted in the generation of high affinity aptamers and development of an aptasensor which can have wide application in the food industry for high throughput screening of samples for patulin contamination within a short span of time.

Enzyme decorated dendritic bimetallic nanocomposite biosensor for detection of HCHO.

In recent times, bi- and tri-metallic nanocomposites are being extensively studied to improve the catalytic surface and sensitivity of detection. In this study, we designed a formaldehyde dehydrogenase decorated Cys-AuPd-ErGO nanocomposite with fern like AuPd dendrites deposited on reduced graphene oxide (ErGO) on screen printed electrode (SPE) for determination of NADH and successfully demonstrated its application for detection of HCHO. This biosensor exhibited direct electron transfer by lowering the oxidation potential of NADH from +0.63 V to 0.32 V vs Ag/AgCl, avoiding usage of electron mediators. The sensor LOD was 0.3 µM HCHO with excellent sensitivity of 70 µA/µM/cm2 and linear detection range between 1 µM and 100 µM during chronoamperometric studies at applied over potential of +0.35 V vs Ag/AgCl. The sensor was tested for its performance in simulated HCHO adulterated samples of fish and milk, and appreciable recoveries (88-104%) at tested concentrations indicated good sensor performance. It was also validated against conventional method of HPLC with highly acceptable correlation coefficient of 0.99, indicating successful fabrication of a simple, "on site" disposable sensor for HCHO detection. The developed biosensor can also find wide application in quantitative measurement of NADH and analytes involved in reactions with the co-enzyme.

Ozone assisted autohydrolysis of wheat bran enhances xylooligosaccharide production with low generation of inhibitor compounds: A comparative study.

In the present study, ozone assisted autohydrolysis (OAAH) was evaluated for enhanced generation of xylooligosaccharide (XOS) from wheat bran. The total XOS yield with optimum ozone dose of 3% (OAAH-3) was found to be 8.9% (w/w biomass) at 110 °C in comparison to 7.96% at 170 °C by autohydrolysis (AH) alone. Although, there was no significant difference in oligomeric composition (DP 2-6), significant decrease in degradation products namely furfural (2.78-fold), HMF (3.15-fold), acrylamide (nil) and acetic acid (1.06-fold), was observed with OAAH-3 as a pretreatment option. There was 1-fold higher xylan to XOS conversion and OAAH-hydrolysate had higher DPPH radical scavenging activity than AH. PCA plots indicated clear enhancement in XOS production and lower generation of inhibitors with decrease in treatment temperature. Results of the study therefore suggest OAAH can be an effective pretreatment option that can further be integrated with downstream processing for concentration and purification of XOS.

DNA aptamer selection and detection of marine biotoxin 20 Methyl Spirolide G.

This study reports the selection of DNA aptamer for the detection of 20 Methyl Spirolide G (SPXG). After 10 rounds of selection, theenriched pool of aptamers specific to SPXGwas cloned, sequenced and clustered into seven families based onsimilarity. Three sequences SPX1, SPX2 and SPX7, each belonging to different clades were further evaluated for their binding affinity. Surface plasmonresonancestudies determined the highest affinity KDof 0.0345x10-8 M for aptamer SPX7. A label-free microscale thermophoresis-based aptasensing using SPX7 with highest affinity, indicated a linear detection range from 1.9 to 125000 pg/mL (LOD = 0.39 pg/mL; LOQ = 1.17 pg/mL). Spiking studies in simulated contaminated samples of mussel and scallop indicated recoveries in the range of 86 to 108%. Results of this study indicate the successful development of an aptamer for detection of SPXG at picogram levels. It also opens up avenues to develop other sensing platforms for detection of SPXG using the reported aptamer.

Colorimetric and chemiluminescence based enzyme linked apta-sorbent assay (ELASA) for ochratoxin A detection.

Ochratoxin A (OTA) is one of the most widespread mycotoxin found to contaminate various food products such as cereals, spices, groundnuts, coffee, wine, beer etc. It is also carried over from contaminated feed and fodder to milk, blood, meat, kidney and liver of animals consuming it. Enzyme-linked to biorecognition molecules like antibodies or aptamers are very popular due to their ability to be used as labels or tags in biosensing formats. In this work, OTA aptamer based colorimetric and chemiluminescence biosensing formats were evaluated for the detection of OTA. The colorimetric enzyme linked apta-sorbent assay (Co-ELASA) and chemiluminescence enzyme linked apta-sorbent assay (Cl-ELASA) showed a linear detection range from 1 pg/mL to 1 µg/mL with a limit of detection (LOD) of 0.84 pg/mL for Co-ELASA (limit of quantification (LOQ) = 2.54 pg/mL) and 1.29 pg/mL for Cl-ELASA (LOQ = 3.94 pg/mL) under optimized buffer conditions. Comparison of ELASA methods with sandwich ELISA indicated that the developed techniques had sensitivity similar to the conventional technique which indicated a LOD of 1.13 pg/mL and LOQ of 3.41 pg/mL. Studies in simulated contaminated food samples by spiking OTA in groundnut and coffee bean at concentrations of 0.1, 1 and 10 ppb, indicated recoveries in the range of 50.21 to 113.27% for Co-ELASA, 90.47 to 107.72% for Cl-ELASA and 76.23 to 141.49% for ELISA. Results of the study indicate that Co-ELASA and Cl-ELASA assays could be an alternate approach for ultrasensitive detection of OTA in food samples, which can also be adapted for biosensor development.

Differential Interaction of Metal Ions with Gold Nanoclusters and Application in Detection of Cobalt and Cadmium.

Interest in biosensing platforms using protein fluorescent gold nanoclusters (FGNCs) has grown significantly in the past due to the unique optical properties they offer. This study investigates the interaction of metal ions with FGNCs, and the structural modifications brought about by the interaction resulting in fluorescence changes of the cluster and its successful application in the detection of two heavy metals, cobalt and cadmium. The binding of cobalt and cadmium to FGNCs synthesized from BSA significantly altered the secondary structure of the protein, causing a change in its hydrophobicity. It also resulted in a change in fluorescence properties of FGNCs by intersystem crossing (ICT) and fluorescence resonance energy transfer (FRET). Cobalt and cadmium could successfully be detected in the range of 5-165 ng/mL (R2 = 0.95) and 20-1000 ng/ mL (R2 = 0.91), respectively, with appreciable sensitivity. The principle was also applied for the detection of Vitamin B12 in commercially available ampoules, validating the proposed method. Graphical Abstract Proposed detection method of cadmium and cobalt using FGNCs.

Aptamer as capture agent in enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of Aflatoxin B1.

Aflatoxin B1 (AFB1), is one of the most toxic mycotoxins found to contaminate various food commodities like cereals, dried fruits, tree nuts, spices and crude vegetable oils. In spite of considerable progress in analytical techniques, there is still a need to develop rapid and highly sensitive detection platforms for AFB1. In this study, AFB1 specific aptamer was used as a capture molecule to develop an enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of AFB1. Under optimized conditions, the assay had a linear detection range from 1 µg to 1 pg with a limit of detection (LOD) of 1 pg/mL in buffer. Conventional ELISA with AFB1 hapten as the capture agent (LOD = 10 pg/mL) was also carried out to compare the results with the present method. Recovery studies in food samples like dried red chillies, groundnut and pepper using both the methods was found to be in the range of 88.49-106.4% at 10 ng/mL and 87.4% to 95.8% at 5 ng/mL for ELASA and 76.56-127.68% at 10 ng/mL and 82-101.2% at 5 ng/mL for ELISA. Higher detection (10 fold) and better recovery using ELASA suggest that the method could offer an early, ultrasensitive, high-throughput, qualitative and semi-quantitative detection of AFB1 in contaminated food samples.

Supramolecular nano-sniffers for ultrasensitive detection of formaldehyde.

Supramolecular nanoparticle hybrids for biosensing of analytes have been a major focus due to their tunable optical and surface properties. Quantum dots-Gold nanoparticle (QDs-GNP) based FRET probes involving turn on/off principles have gained immense interest due to their specificity and sensitivity. Recent focus is on applying these supramolecular hybrids for enzyme operated biosensors that can specifically turn-on fluorescence induced by co-factor or product formed from enzymatic reaction. The present study focuses on locking and unlocking the interaction between QD-GNP pair leading to differential fluorescent properties. Cationic GNPs efficiently quenched the anionic QD fluorescence by forming nanoparticle hybrid. Quenching interaction between QD-GNP pair was unlocked by NADH leading to QD fluorescence turn-on. This phenomenon was applied for the successful detection of formaldehyde using NAD+ dependent formaldehyde dehydrogenase. The proposed nano-sniffer could successfully detect formaldehyde from 0.001 to 100000ng/mL (R2 = 0.9339) by the turn off-turn on principle. It could also detect formaldehyde in fruit juice and wine samples indicating its stability and sensitivity in real samples. The proposed nanoprobe can have wide applications in developing enzyme biosensors in future.

Antiaflatoxigenic and Antimicrobial Activities of Schiff Bases of 2-Hydroxy-4-methoxybenzaldehyde, Cinnamaldehyde, and Similar Aldehydes.

2-Hydroxy-4-methoxybenzaldehyde (HMBA) is a nontoxic phenolic flavor from dietary source Decalipus hamiltonii and Hemidesmus indicus. HMBA is an excellent antimicrobial agent with additional antiaflatoxigenic potency. On the other hand, cinnamaldehyde from cinnamon is a widely employed flavor with significant antiaflatoxigenic activity. We have attempted the enhancement of antiaflatoxigenic and antimicrobial properties of HMBA, cinnamaldehyde, and similar molecules via Schiff base formation accomplished from condensation reaction with amino sugar (d-glucamine). HMBA derived Schiff bases exhibited commendable antiaflatoxigenic activity at the concentration 0.1 mg/mL resulting in 9.6 ± 1.9% growth of Aspergillus flavus and subsequent 91.4 ± 3.9% reduction of aflatoxin B1 with respect to control.

Fluorescent competitive aptasensor for detection of aflatoxin B1.

Aflatoxin B1 (AFB1 ) is one of the most commonly found mycotoxins in food commodities, particularly cereals, oilseeds, spices and tree nuts. In the past decade, aptamers have come into limelight and emerged as a new biosensing element replacing antibodies in various detection formats. Herein we report a faster, more sensitive, high throughput method for the detection of AFB1 using AFB1 -specific aptamers. The assay format was based on a competitive reaction of the fluorescent tagged aptamer specific to AFB1 with the aflatoxin conjugate. Under optimal conditions, a linear range of detection (50 ng to 50 pg) was achieved with a limit of detection (LOD) of 10 pg/mL in the buffer system. Results of inter- and intra-assay revealed that the assay was repeatable with standard deviation in acceptable range. The assay was also validated in food samples such as dried red chilies, groundnut and whole pepper with recovery in the range of 92 to 102% at 10 ng/mL and 100 pg/mL levels. The aptasensor assay was also compared with standard analytical method of HPLC and was found to be more sensitive. This detection technique has the potential to be developed into a biosensor platform for AFB1 detection.

Tunneling of redox enzymes to design nano-probes for monitoring NAD(+) dependent bio-catalytic activity.

Monitoring of bio-catalytic events by using nano-probes is of immense interest due to unique optical properties of metal nanoparticles. In the present study, tunneling of enzyme activity was achieved using redox cofactors namely oxidized cytochrome-c (Cyt-c) and Co-enzyme-Q (Co-Q) immobilized on Quantum dots (QDs) which acted as a bio-probe for NAD(+) dependent dehydrogenase catalyzed reaction. We studied how electron transfer from substrate to non-native electron acceptors can differentially modify photoluminescence properties of CdTe QDs. Two probes were designed, QD-Ox-Cyt-c and QD-Ox-Co-Q, which were found to quench the fluorescence of QDs. However, formaldehyde dehydrogenase (FDH) catalyzed reduction of Cyt-c and Co-Q on the surface of QDs lead to fluorescence turn-on of CdTe QDs. This phenomenon was successfully used for the detection of HCHO in the range of 0.01-100,000ng/mL (LOD of 0.01ng/mL) using both QD-Ox-Cyt-c (R(2)=0.93) and QD-Ox-Co-Q (R(2)=0.96). Further probe performance and stability in samples like milk, wine and fruit juice matrix were studied and we could detect HCHO in range of 0.001-100,000ng/mL (LOD of 0.001ng/mL) with good stability and sensitivity of probe in real samples (R(2)=0.97). Appreciable recovery and detection sensitivity in the presence of metal ions suggests that the developed nano-probes can be used successfully for monitoring dehydrogenase based bio-catalytic events even in the absence of NAD(+). Proposed method is advantageous over classical methods as clean up/ derivatization of samples is not required for formaldehyde detection.

Fluorescence Based Turn-on Probe for the Determination of Caffeine Using Europium-Tetracycline as Energy Transfer Complex.

The study describes a simple and sensitive fluorometric sensor based on the enhancement of fluorescence intensity of Europium ion (Eu(3+)) - tetracycline (TC) charge transfer complex on addition of caffeine. The Eu(3+)-TC ternary complex has a characteristic emission peak at 615 nm (λex = 375 nm), the intensity of which increases with increase in concentration of caffeine. The caffeine sensor assay was found to be linear in the range of 0.0515 mM to 51.5 mM. The limit of detection and quantification were found to be 0.0515 mM and 0.382 mM, respectively. A caffeine recovery of 90 to 110 % in biological samples (serum and urine) indicated minimal interference by commonly present excipients in the samples. Rosenthal plots to calculate the binding capacity of caffeine with the Eu(3+)- TC complex revealed an association constant (K) of 238 x 10(3) L/mol and binding number (N) of 1.9. Bland-Altman plot comparing the developed assay and HPLC showed good agreement between values obtained by both the methods. The proposed fluorescent chemical sensor is a rapid and convenient method to determine caffeine with excellent recovery and low detection limit. The probable reaction mechanism for the formation of the turn on fluorescent probe enhancer is discussed.

Response Surface Optimization for Decaffeination and Theophylline Production by Fusarium solani.

Coffee processing industries generate caffeine-containing waste that needs to be treated and decaffeinated before being disposed. Five fungal isolates obtained on caffeine-containing mineral media were tested for their ability to utilize caffeine at high concentrations. An isolate identified as Fusarium solani could utilize caffeine as a sole source of carbon and nitrogen up to 5 g/l and could degrade it to an extent of 30-53 % in 120 h. Sucrose that was added as an auxiliary substrate (5 g/l) enhanced the biodecaffeination of caffeine to 88 % in 96 h. The addition of co- substrate (sucrose) not only resulted in higher biodecaffeination efficiency, but also reduced the incubation period from the initial 120 to 96 h. Theophylline and 3-methyl xanthine were obtained as the major metabolites of decaffeination at 96 and 120 h, respectively. Response surface methodology used to optimize the process parameters for maximum biodecaffeination as well as theophylline production showed that a pH of 5.8, temperature of 24 °C and inoculum size of 4.8 × 10(5) spores/ml have resulted in a complete biodecaffeination of caffeine as well as the production of theophylline with a yield of 33 % (w/w). Results thus show that a viable and sustainable process can be developed for the detoxification of caffeine along with the recovery of theophylline, a commercially important chemical.

Plectranthus amboinicus leaves stimulate growth of probiotic L. plantarum: evidence for ethnobotanical use in diarrhea.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves of Plectranthus amboinicus are consumed in India along with buttermilk (a probiotic source) during pathogen induced diarrhea. This treatment is known to reduce the number of episodes as well as duration of diarrhea. AIM OF THE STUDY: In the background of its ethnobotanical use, the present investigation was carried out to determine whether, apart from having an antimicrobial activity on pathogens, the leaves could possibly also have a positive effect on the beneficial microflora of the gut resulting in accelerated microbial ecological balance. MATERIALS AND METHODS: The growth stimulating activity of the hot water extract (HWE) of P. amboinicus leaves on probiotic Lactobacillus plantarum was determined by microbroth dilution technique and viable plate count method in selective medium (MRS) as well as in fermented milk. The ability of the bacteria to utilize the phytoconstituents of HWE primarily phenolic acids and sugars was determined by assaying for phenolic acid decarboxylase by SDS-PAGE and ß-galactosidase activity by ß-gal ONPG assay. RESULTS: HWE of P. amboinicus leaves inhibited growth of pathogens (Escherichia coli and Salmonella typhimurium) while stimulated the growth of L. plantarum. SDS-PAGE gel showed the presence of phenolic acid decarboxylase enzyme induced in the presence of HWE in L. plantarum indicating the utilization of polyphenols by the bacteria. Cells grown on HWE also showed ß-galactosidase activity indicating their ability to utilize sugars present in HWE. CONCLUSION: Indian borage leaves have a prebiotic effect on the probiotic bacteria (L. plantarum) which utilizes the phytoconstituents of the leaves by producing necessary metabolic enzymes. This work provides evidence in the traditional use of the leaves in the alleviation of diarrhea by accelerating microbial gut balance during infection.

Inhibition of LDL oxidation and oxidized LDL-induced foam cell formation in RAW 264.7 cells show anti-atherogenic properties of a foliar methanol extract of Scoparia dulcis.

BACKGROUND: Oxidation of low density lipoproteins and their further uptake by macrophages is known to result in the formation of foam cells, which are critical in the initiation of atherosclerosis through activation of inflammatory signalling cascades. Thus, powerful dietary antioxidants are receiving attention for the reversal of such pathological states. MATERIALS AND METHODS: Extracts of Scoparia dulcis have been used as tea and health drinks with various health promoting effects. In the present study, we examined the reactive oxygen scavenging potential as well as anti-inflammatory and anti-atherogenic efficacies, using leaf extracts obtained after successive extraction with various solvents. RESULTS: A methanol extract showed potent antioxidant activity with an IC50 value of 570 µg/ml, caused hydrogen peroxide scavenging (28.9 µg/ml) and anti-inflammatory effects by improving human erythrocyte membrane stabilisation (about 86%). The methanol extract also efficiently inhibited lipid peroxidation and oxidation of low density lipoproteins, thus preventing foam cell formation in cultured RAW 264.7 cells. Furthermore, phytochemical screening of the extracts showed high accumulation of flavonoids. CONCLUSIONS: The foliar methanol extract of Scoparia dulcis has a strong anti-atherogenic potential and this property could be attributed maybe due to presence of flavonoids since HPLC analysis showed high concentrations of myricetin and rutin in the methanol extract.