Phytochemicals of ethanolic extract and essential oil of Persicaria hydropiper and their potential as antibacterial agents for food packaging polylactic acid film

This study aims to determine phytochemicals and antibacterial activity of ethanolic extract and essential oil of Persicaria hydropiper, and their potential as antibacterial agents in polylactic acid (PLA) film. The yield of ethanolic extract and essential oil were 11.02 and 0.70%, respectively. Chlorogenic acid, ferulic acid, rutin, myricetin and quercetin were detected as major components in the P. hydropiper ethanolic extract, while dodecanal, caryophyllene, caryophyllene oxide, decanal, α‐caryophyllene, citronellol, heptadecanal, linalool and phytol were detected in the P. hydropiper essential oil. Based on the disc diffusion assay, both ethanolic extract and essential oil of P. hydropiper possessed antibacterial activity against bacteria Staphylococcus aureus only at different concentrations, with minimum inhibitory concentration values: 0.625 and 5 mg/ml, respectively; and minimum bactericidal concentration values: 5 and 40 mg/ml, respectively. However, they found to show antibacterial activity against three bacteria S. aureus, Escherichia coli and Salmonella Typhimurium at different concentrations and time using time‐kill kinetics assay. Incorporation of ethanolic extract and essential oil in PLA film also exhibited an antibacterial effect against S. aureus. Our findings confirmed the potential use of both P. hydropiper ethanolic extract and essential oil as antibacterial agents in biodegradable PLA film.     

Antimicrobial activity of food-compatible plant extracts and chitosan against naturally occurring micro-organisms in tomato juice

BACKGROUND: Chitosan (AC) and five hydroalcoholic extracts from Lithospermum erythrorhizon (SE), Rheum palmatum (RE), Thymus vulgaris (AT), Lippia citriodora (PLX) and a mixture of Rosmarinus officinalis, Salvia lavandulifolia and Thymus mastichina (LA) were tested for antimicrobial activity against bacteria, yeasts and filamentous fungi using two broth dilution methods. The effects of adding single extracts on naturally occurring micro‐organisms and sensory qualities of raw tomato juice were also evaluated. RESULTS: SE extract exhibited the strongest activity, with minimum inhibitory concentrations (MICs) of 100–400 µg mL^?1 for Gram‐positive and 1600–3200 µg mL^?1 for Gram‐negative bacteria. Enterobacter aerogenes showed the greatest susceptibility to AC (MIC 1600 µg mL^?1). Lethal effects of extracts and AC were achieved at a minimum bactericidal concentration (MBC)/MIC ratio of 2 in 88% of assays. SE and RE extracts and AC also exhibited antifungal effect against yeasts, but they had no activity on filamentous fungi. Control and 100 mg L^?1 SE‐added tomato juices did not differ in acceptance, but this SE concentration was not effective in the control of microbial load throughout cold storage. CONCLUSION: Results confirm the antimicrobial potential of the plant extracts, but additional research is needed until the agents responsible for the activities have been determined in order to use them as natural constituents of multiple‐barrier food preservation systems. Copyright © 2012 Society of Chemical Industry     

Antioxidant Capacities,Phenolic Contents,and GC/MS Analysis of Rhodiola imbricata Edgew. Root Extracts from Trans‐Himalaya

Our aim was to assess the antioxidant capacities and phenolic constituents of methanol and aqueous extracts of Rhodiola imbricata Edgew. root from Trans‐Himalayan cold desert of Ladakh. The 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) radical scavenging capacity of the root extracts increased in a dose‐dependent manner (up to 0.1 mg/mL) and root extract concentrations required for 50% inhibition of radical scavenging effect (IC₅₀) were recorded as 0.013 and 0.014 mg/mL (for DPPH) and 0.016 and 0.017 mg/mL (for ABTS) for methanol and aqueous extracts, respectively. The total antioxidant power of the extract was determined by ferric reducing antioxidant power (FRAP) assay. Total polyphenol and phenolic acid content of methanol and aqueous extracts were 112.24, 59.06, 39.02, and 16.95 mg gallic acid equivalent/g of extract, respectively. Total flavonoid and flavonol contents were estimated to be 30.2, 17.67, 20.68, and 7.38 mg quercetin equivalent/g of extract, respectively. In all antioxidant capacity assays, the methanol extract exhibited significantly higher antioxidant capacity than that of aqueous extract due to the presence of significantly higher amount of vital phytoconstitiuents, viz. polyphenol, phenolic acid, and flavonol. GC/MS analysis showed that phytosterols, alkyl halide, phenols, and fatty acid esters were major phytochemical clusters. On the other hand, monoterpenes, fatty acids, tocopherols, aliphatic hydrocarbons, and ethers were found to be present in comparatively less amount in the methanol extract. Hence, our study signifies that this high‐altitude medicinal herb could be used as the natural source of antioxidants and supports its use in traditional system of medicine to ameliorate oxidative stress and high‐altitude maladies.     

Correlation between Antimicrobial,Antioxidant Activity,and Polyphenols of Alkalized/Nonalkalized Cocoa Powders

Many factors can influence antioxidative and antimicrobial characteristics of plant materials. The quality of cocoa as functional food ingredient is influenced through its processing. The main aim of this study was to test if there is difference in polyphenol content, antioxidant capacity, and antimicrobial activity between nonalkalized and alkalized cocoa powders. To estimate polyphenol and flavonoid content in cocoa samples the spectrophotometric microassays were used. Flavan‐3ols were determined with reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Antimicrobial activity against 3 Gram positive bacteria, 4 Gram negative bacteria and 1 strain of yeast was determined using broth microdilution method. Total polyphenol content was 1.8 times lower in alkalized cocoa samples than in natural ones. Epicatechin/catechin ratio was changed due to the process of alkalization in favor of catechin (2.21 in natural and 1.45 in alkalized cocoa powders). Combined results of 3 antioxidative tests (DPPH, FRAP, ABTS) were used for calculation of RACI (Relative Antioxidant Capacity Index) and GAS (Global Antioxidant Score) values that were consistently higher in natural than in alkalized cocoa extracts. Obtained results have shown significant correlations between these values and phenolic content (0.929 ≤ r ≤ 0.957, P < 0.01). Antimicrobial activity varied from 5.0 to 25.0 mg/ml (MICs), while Candida albicans was the most sensitive tested microorganism. Cocoa powders subjected to alkalization had significantly reduced content of total and specific phenolic compounds and reduced antioxidant capacity (P < 0.05), but their antimicrobial activity was equal for Gram‐positive bacteria or even significantly enhanced for Gram‐negative bacteria.     

Impact of icing systems with aqueous,ethanolic and ethanolic‐aqueous extracts of alga Fucus spiralis on microbial and biochemical quality of chilled hake (Merluccius merluccius)

The study focuses on the impact of icing systems with aqueous (AQ batch), ethanolic (ET batch) and ethanolic‐aqueous (ET‐AQ batch) extracts of alga Fucus spiralis on the microbial and biochemical quality of chilled hake (Merluccius merluccius). After a 13‐day storage, comparison with fish kept under traditional ice proved a significant (P < 0.05) antimicrobial effect against aerobes, psychrotrophs, proteolytic and lipolytic bacteria, derived of the presence of F. spiralis ethanolic extracts in the icing medium (ET and ET‐AQ batches). Additionally, an inhibitory effect of both ethanol extracts was also obtained concerning lipid oxidation development (i.e. secondary and tertiary lipid oxidation compounds). Additionally, lipid damage assessment showed lower mean values in tertiary oxidation compound formation in hake belonging to the ET‐AQ batch throughout the whole storage period. Present research indicates that ET‐AQ ice condition can lead to a marked quality and safety enhancement as well as to profitable commercial value increases.     

In Vivo Genotoxicity Evaluation of an Artichoke (Cynara scolymus L.) Aqueous Extract

The Cynara scolymus (artichoke) is widely consumed as tea or food and shows important therapeutic properties. However, few studies have assessed the possible toxic effects of artichoke extracts. This study evaluates genotoxic and mutagenic activities of artichoke leaf aqueous extract in mice using the comet assay and the micronucleus test. Leaf extracts were given by gavage (500 mg/kg, 1000 mg/kg, and 2000 mg/kg) for 3 consecutive days. Extract composition was investigated using phytochemical screening and high‐performance liquid chromatography (HPLC). In addition, antioxidant capacity was analyzed through the diphenyl‐picrylhydrazyl (DPPH) and xanthine oxidase assay. Phytochemical screening detected the presence of phenolic compounds, flavonoids, and saponins. HPLC analyses indicated the presence of chlorogenic acid, caffeic acid, isoquercetrin, and rutin. Extracts showed a dose‐dependent free radical scavenging effect of DPPH and an inhibitory effect of xanthine oxidase. The genotoxic results showed that leaf extracts did not increase micronuclei in peripheral blood cells. Compared to the control group, a significant increase in comet assay values was observed only in bone marrow of group treated with 2000 mg/kg, the highest dose tested, indicating that artichoke tea should be consumed with moderation. Practical Application: This is the first report of in vivo mutagenic and genotoxic evaluation with C. scolymus. The present study revealed leaf aqueous extract from artichoke shows lack of mutagenicity in vivo, and low genotoxicity and antioxidant activity; indicating that artichoke tea should be consumed with moderation.     

Antioxidation and antiglycation of 95% ethanolic extracts prepared from the leaves of black nightshade (Solanum nigrum)

Hyperglycemia results in the formation of advanced glycation end-products (AGE), resulting in an inflammatory response that induces insulin resistance. Evidence indicates that antioxidants can suppress the formation of reactive oxygen species, decrease levels of AGEs by inhibiting glycation. Black nightshade (Solanum nigrum) can be used as a medicinal food for improving blood glucose; however, the identities of the active compounds and how they counteract diabetes remain unknown. This study demonstrate that 95% ethanolic extracts of black nightshade exerted significant antioxidative activity compared with 50% ethanolic extracts and aqueous extracts. Moreover, 95% ethanolic extracts of black nightshade produced antiglycative activity, which contributed to the inhibition of fructosamine and generation of α-dicarbonyl compounds. The concentrations of solasonine and solamargine in the 95% ethanolic extracts were 0.484 and 0.183 mg/mg, respectively. These results suggest that black nightshade might serve as a novel source of functional ingredients that exert antiglycation and anti-diabetes activities.     

Phytochemicals and antioxidant activity of fruits and leaves of paprika (Capsicum Annuum L., var. special) cultivated in Korea

The phytochemical composition of carotenoids, tocopherols, free sugars, organic acids, L-ascorbic acid, capsaicinoids, and flavonoids in green and red paprika (GP and RP), and paprika leaves (PL) cultivated in Korea were analyzed. The ethanolic extracts of GP, RP, and PL were obtained with 80% ethanol, and their antioxidative activities were determined by measuring their ABTS and DPPH radical scavenging activities. RP showed the highest contents of capsanthin (58.33 ± 3.91 mg/100 g dry weight) and L-ascorbic acid (1987.25 ± 19.64 mg/100 g dry weight), and main compounds of PL were lutein, chlorophyll, and γ-tocopherol (96.91 ± 14.58, 2136.71 ± 21.11, and 723.49 ± 54.10 mg/100 g dry weight, respectively). RP showed the strongest antioxidant activity (IC(50) = 55.23 ± 6.77 μg/mL in a 2, 2'-azino-di-[3-ethylbenzthiazoline sulphonate] assay and 150.40 ± 8.07 μg/mL in a 2, 2-diphenyl-2-picrylhydrazyl assay), and the antioxidant activity of PL was higher than β-carotene but lower than RP. The results indicate that the amounts of capsanthin and L-ascorbic acid in RP correlate well with antioxidant activity. PL, which has various phytochemicals such as lutein, chlorophyll, and γ-tocopherol, might be used in nutraceuticals and pharmaceuticals for improving human health.     

Bioactivities of kernel extracts of 18 strains of maize (Zea mays)

Abstract: Aqueous and ethanolic extracts of maize kernels from 18 varieties/strains were prepared for the evaluation of inhibitory activities toward α-glucosidase and scavenging activities toward nitric oxide (NO•) and superoxide (•O₂⁻). All ethanolic extracts of maize strains tested inhibited yeast (Saccharomyces cerevisiae) α-glucosidase with the highest potency (49% to 54%) found for 2 purple and a yellow strains. However, inhibitory effects of maize extracts on rat intestinal α-glucosidase were as a whole about 10% as effective as with the yeast enzyme. Maize extracts were capable of scavenging NO• at the level of 0.25 mg/mL to extents ranging from 24% to 50% and 26% to 57%, respectively, for aqueous and ethanolic extracts. All tested aqueous extracts were also capable of scavenging •O₂⁻, with efficacies ranging from 8% to 38%, at the level of 1.5 mg/mL, whereas almost none of the ethanolic extracts scavenged •O₂⁻, except for one purple strain (approximately 10% effective). The effectiveness in the enzyme inhibition and antioxidant assays did not correlate with total phenolic and/or anthocyanin levels, nor with the nature of pigmentation among the maize strains evaluated. Practical Application : A diversity of pigmented maize strains was evaluated for biological activities related to mitigating oxidative stress and slowing down glucose absorption from the diet. Certain strains tended to be more abundant in these biological activities and have potential to be used in dietary regimes that are designed to promote human health.     

Potent Antidiabetic Activity and Metabolite Profiling of Melicope Lunu‐ankenda Leaves

Diabetes mellitus is normally characterized by chronic hyperglycemia associated with disturbances in the fat, carbohydrate, and protein metabolism. There is an increasing trend of using natural products instead of synthetic agents as alternative therapy for disorders due to their fewer side effects. In this study, antidiabetic and antioxidant activities of different Melicope lunu‐ankenda (ML) ethanolic extracts were evaluated using inhibition of α‐glucosidase and 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radicals scavenging activity, respectively; whereas, proton nuclear magnetic resonance (¹H NMR) and ultra‐high performance liquid chromatography‐tandem mass spectrometric (UHPLC‐MS/MS) techniques were used for metabolite profiling of ML leaf extracts at different concentrations of ethanol and water. Sixty percent of ethanolic ML extract showed highest inhibitory effect against α‐glucosidase enzyme (IC₅₀ of 37 μg/mL) and DPPH scavenging activity (IC₅₀ of 48 μg/mL). Antidiabetic effect of ML extracts was also evaluated in vivo and it was found that the high doses (400 mg/Kg BW) of ML extract exhibited high suppression in fasting blood glucose level by 62.75%. The metabolites responsible for variation among ML samples with variable ethanolic levels have been evaluated successfully using ¹H‐NMR–based metabolomics. The principal component analysis (PCA) and partial least squares(PLS) analysis scores depicted clear and distinct separations into 4 clusters representing the 4 ethanolic concentrations by PC1 and PC2, with an eigenvalue of 69.9%. Various ¹H‐NMR chemical shifts related to the metabolites responsible for sample difference were also ascribed. The main bioactive compounds identified attributing toward the separation included: isorhamnetin, skimmianine, scopoletin, and melicarpinone. Hence, ML may be used as promising medicinal plant for the development of new functional foods, new generation antidiabetic drugs, as a single entity phytomedicine or in combinational therapy.     

Growth inhibition of foodborne pathogens by co‐microencapsulation of lactobacilli cell free and propolis extracts

Cell free extracts (CFE) obtained from Lactobacillus plantarum FI 8595 and Lactobacillus reuteri ATCC 55730 alone or in combination with propolis ethanolic or water extracts (1%) were microencapsulated with maltodextrin (25%) before the subsequent spray drying process. They were morphologically characterized by scanning electron microscope. Chemical compositions of pure extracts were identified by gas chromatography–mass spectrometry. Antimicrobial activities of pure and microencapsulated extracts against four foodborne pathogens (Staphylococcus aureus ATCC29213, Listeria monocytogenes ATCC19112, Klebsiella pneumoniae ATCC700603 and Salmonella Paratyphi A NCTC13) were determined using agar well diffusion, broth microdilution and time kill assays. CFE from L. reuteri and L. plantarum consisted of acetic acid, pyrrolo[1,2‐a]pyrazine‐1,4‐dione, hexahydro‐3‐(phenylmethyl)‐, 2,3,4‐trihydroxybenzaldehyde and 9‐octadecenoic acid. The results also indicated the presence of two respective major compounds, namely, 2‐methoxy‐4‐vinylphenol (19.03%) and trans‐cinnamic acid (27.67%) in water and ethanolic propolis extracts. Presence of propolis extracts mainly ethanolic extract in microencapsulation led to higher inhibition zones against all foodborne pathogens (p < .05). The co‐microencapsulation of CFE from L. reuteri in combination with ethanolic or water extract of propolis resulted in 2.34‐ and 2.2‐fold higher inhibition zone towards L. monocytogenes. Pure and microencapsulated CFE from L. reuteri resulted in 2.89 and 2.14 log cfu/ml reduction in growth of S. Paratyphi A at 3 hr, respectively. The co‐microencapsulation of CFE from lactobacilli and propolis extracts mainly ethanolic extract could be suggested as a novel antimicrobial on inhibition of food pathogens, as they contain abundant bioactive substances.     

Chemical composition, antioxidant and antibacterial properties of the essential oils of Etlingera elatior and Cinnamomum pubescens Kochummen

BACKGROUND: Plant essential oils are widely used as fragrances and flavours. Therefore, the essential oils from the leaves of Cinnamomum pubescens Kochummen (CP) and the whole plant of Etlingera elatior (EE) were investigated for their antioxidant, antibacterial and phytochemical properties. RESULTS: CP and EE were found to contain appreciable levels of total phenolic contents (50.6 and 33.41 g kg^?1 as gallic acid equivalent) and total flavonoid contents (205.6 and 244.8 g kg^?1 as rutin equivalent), respectively. DPPH free radical scavenging activity of CP is superior to EE (P < 0.05) showing IC₅₀ of 77.2 and 995.1 µg mL^?1, respectively. Methicillin‐resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Pseudomonas aeruginosa and Salmonella choleraesuis were tested against CP and EE. Only MRSA was the most susceptible bacteria to CP. GC/MS studies resulted in the identification of 79 and 73 compounds in CP and EE, respectively. The most abundant components of EE included β‐pinene (24.92%) and 1‐dodecene (24.31%). While the major compound in CP were 1,6‐octadien‐3‐ol,3,7‐dimethyl (11.55%), cinnamaldehyde (56.15%) and 1‐phenyl‐propane‐2,2‐diol diethanoate (11.38%). CONCLUSION: This study suggests that the essential oils from Cinnamomum pubescens Kochummen and Etlingera elatior could be potentially used as a new source of natural antioxidant and antibacterial in the food and pharmaceutical industries. Copyright © 2010 Society of Chemical Industry     

Chemical,antioxidant and antibacterial study of Brazilian fruits

In this study, the antioxidant capability, total phenolic content and antimicrobial activity of ethanolic extracts of seven fruits from the Brazilian Atlantic Forest were evaluated. The conditions for the extraction of crude phenolics from the fruits were determined using an experimental factorial design. Total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH^?) scavenging activity and β‐carotene‐linoleic acid couple oxidation assays were used to evaluate the antioxidant properties of the extracts. In addition, antimicrobial activity was screened using two Gram‐negative bacteria (Escherichia coli and Klebsiella pneumoniae) and one Gram‐positive bacterium (Staphylococcus aureus). All native fruits assayed in this study have high potential as natural antioxidant sources. Among the seven fruits evaluated, Jabuticaba and Uvaia had the highest antioxidant activity in the DPPH^? and of β‐carotene‐linoleic acid coupled oxidation assays. In the biological assay, K. pneumoniae was the most sensitive microorganism to the fruit extracts, and the Jabuticaba extract had a slight inhibitory effect against this Gram‐positive bacterium.     

Antioxidant activity of phytogenous industrial waste and derived extracts for the production of feed and food additives

Organic wastes as well as their ethanolic, water and heptane extracts and fermented products derived from herbs, fruit and vegetables obtained worldwide from food and pharmaceutical industries were investigated regarding their antioxidant activities using different methods [1.1‐diphenyl‐2‐picrylhydrazyl, Fe^III‐reduction method and photochemiluminescence (PCL)]. The highest antioxidative activities were exhibited by different products of grape seed wastes (350–830 mg rosmarinic acid equivalent g^?1 dried material = rae g^?1 dm) followed by ethanolic extracts of blueberry (475 mg rae g^?1 dm), larch (219 mg rae g^?1 dm), willow (193 mg rae g^?1 dm) and sunflower presscake (154 mg rae g^?1 dm). Ethanolic extracts of the residues showed comparatively higher activity than water extracts. The least antioxidative capacities were found in heptane extracts of serenoa products (0.4; 0.6 mg rae g^?1 dm) and fermented waste of carrots (1.6 mg rae g^?1 dm). Correlating different assay methods, the strongest correlation was found between Fe^III‐reduction and DPPH‐method (correlation coefficient r² = 0.99**) and the weakest between Fe^III‐reduction and PCL method (r² = 0.57**) for raw materials.     

Polyphenolic Composition and Antioxidant Activities of Grape Seed Extract

Grape seed extracts (GSEs,) obtained from Italian and Rhine Rieslings, were examined for polyphenolic composition and antioxidant activities using HPLC and ESR spectrometry. The seed extraction was carried out with ethyl acetate and ethanol. The contents of polyphenols, flavan-3-ols and antioxidant activities were found to be higher in ethyl acetate than in ethanolic extracts. IC₅₀ values were 0.1045 mg/mL and 0.0599 mg/mL for the stable DPPH radical in ethanolic and ethyl acetate extracts, respectively. The values for the short-lived OH radical were 0.1989 mg/mL and 0.0362 mg/mL, in the given order. The significant correlations between the antioxidant activities of GSEs and polyphenols were established (P < 0.05). Owing to their antioxidant activities, the cultivars could be used as a source to produce a GSE.     

ANTIFUNGAL,AFLATOXIN INHIBITORY AND FREE RADICAL‐SCAVENGING ACTIVITIES OF SOME MEDICINAL PLANTS EXTRACTS

ABSTRACT

The antifungal, aflatoxin inhibitory and antioxidant activity of methanol–aqueous extract (2:1) of 62 medicinal plants was explored. Based on the antifungal results, the extracts of 25 plants showed more than 50% antifungal activity and were further investigated for their aflatoxin inhibition and antioxidant properties. Methanol–aqueous extracts of Phyllanthus emblica and Terminalia chebula fruits caused 100% inhibition of aflatoxin production by the toxigenic strain of Aspergillus flavus in semisynthetic medium at 1 mg/mL. In addition, P. emblica (IC₅₀ = 4.1 µg/mL) and T. chebula (IC₅₀ = 6.9 µg/mL) fruits extracts exhibited strong antioxidant activity during the 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging assay in comparison with butylated hydroxytoluene (IC₅₀ = 8.1 µg/mL) and butylated hydroxyanisole (IC₅₀ = 6 µg/mL).

PRACTICAL APPLICATIONS

Based on the results of the present study, methanol–aqueous extracts of Phyllanthus emblica and Terminalia chebula, being endowed with strong antifungal, aflatoxin inhibitory and antioxidant activity, may be recommended as plant‐based preservatives for the enhancement of shelf life of food items and their protection from the undesirable harmful effects of molds, aflatoxin and free radical‐mediated damages.     

LC–DAD–ESIMS/MS characterization of antioxidant and anticholinesterase constituents present in the active fraction from Persicaria hydropiper

Persicaria hydropiper or ‘kesum’ is a herb used extensively as flavoring agent in food. The antioxidant activity was evaluated by measuring the hydroperoxide production resulting from linoleic acid oxidation using ferric thiocyanate (FTC) as well as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability. Moreover, inhibition activity against cholinesterase, an enzyme that responsible in several physio-pathological processes, was also determined. Identification of phytochemical constituents in the bioactive fraction of P. hydropiper was carried out by LC–DAD–ESIMS/MS technique. Fifteen compounds were identified including flavonoids, flavonoid glycosides and phenylpropanoid glycosides. Six of the compounds were isolated and their structures were elucidated in order to confirm their identities. The antioxidant and antiacetylcholinesterase activities of the isolated compounds were also evaluated.     

ANTIBACTERIAL ACTIVITY OF EXTRACTS FROM FAMILY ZINGIBERACEAE AGAINST FOODBORNE PATHOGENS

Chloroformic extracts of selected Thai medicinal plants commonly employed to treat infections were investigated for their antibacterial activity against important foodborne pathogenic bacteria. These included Bacillus cereus, Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), Escherichia coli O157:H7, Salmonella Typhi and Shigella sp. Among 33 extracts tested, only chloroformic extracts of five plant species exhibited antibacterial properties. Alpinia galanga, Boesenbergia rotunda, Zingiber zerumbet and Piper betel were active against S. aureus. Barleria lupulina was active against B. cereus. Only the extract from P. betel leaves possessed activity against gram‐negative bacteria. As extracts from the three plant species belonging to family Zingiberaceae displayed strong activity against S. aureus, they were further tested against 17 clinical isolates. Minimum inhibitory concentration (MIC) values of B. rotunda, A. galanga and Z. zerumbet extracts against most clinical S. aureus isolates were 0.01, 0.19 and 0.79 mg/mL and the minimum bactericidal concentration (MBC) values were 0.19, 1.57 and >12.5 mg/mL, respectively. Significant growth inhibition of MRSA was observed in the cultures incubated in the presence of the B. rotunda extract, A. galanga and Z. zerumbet. B. rotunda exhibited the greatest activity among the three plant species against S. aureus at MIC, 2MIC and MBC within 2 h.     

Free Radical Scavenging Activity of Aqueous and Ethanolic Extract of Brassica oleracea L. var. italica

In this study, antioxidant activities of aqueous and ethanolic extracts of Brassica oleracea L. var. italica were investigated. The antioxidant properties of both extracts of Brassica oleracea L. var. italica were evaluated using different antioxidant tests, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide radical scavenging, inhibition of microsomal lipid peroxidation, reduction of power, and metal ion chelating activities. Inhibition of superoxide scavenging by aqueous and ethanolic extracts showed an IC₅₀ of 0.93 and 0.25 mg/ml, respectively. Metal ion chelation showed an IC₅₀ of 0.35 mg/ml of both the extracts and was equipotent to positive control, ethylenediamine tetra-acetic acid. The ethanolic extract of Brassica oleracea L. var. italica exhibited higher antioxidant activity in DPPH radical and superoxide anion scavenging than that of aqueous extract. The results obtained in the in vitro models clearly suggest that, Brassica oleracea L. var. italica is a natural source for antioxidants, which could serve as a nutraceutical with potential applications in reducing the level of oxidative stress and related health benefits. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models.     

Evaluation of the Antioxidant Properties of the Brazilian Cerrado Fruit Annona crassiflora (Araticum)

Annona crassiflora, known commonly as araticum, is an exotic tropical fruit consumed mainly by native people of the Brazilian Cerrado (2nd biggest biome of Brazil). In this study, pulp, seed, and peel of slight ripe and overripe fruits were extracted using ethanol and water. The extracts showed high content of total phenols and were screening for their potential as antioxidants using the in vitro model 1,1‐ dipheniyl‐2‐picryl hydrazyl (DPPH). The ethanol extracts of peel and seeds showed IC50 of 48.82 μg/mL and 31.14 μg/mL, respectively, for the slightly ripe fruits. As the ethanolic fractions of araticum showed the highest antioxidant activity, they were selected for testing of its effect on lipid peroxidation. The ethanolic extracts of slightly ripe fruits showed IC₅₀ of 4.44 μg/mL, 1.72 μg/mL, and 8.62 μg/mL for the peel, seed, and pulp, respectively. This is the 1st report on the antioxidant properties of the extracts of araticum. Owing to these properties, the studies can be further extending to exploit them for their possible application as natural antioxidant for cosmetic, supplements, and functional ingredients for food products.