Antioxidative activities of chromatographic fractions obtained from root,fruit and leaf of Mengkudu (Morinda citrifolia L.)

Crude extracts of root, leaf and fruit of Morinda citrifolia were fractionated on a Sephadex LH-20 column with ethanol as eluate. Based on UV absorption intensity of phenolic compound (725 mm) the Sephadex LH-20 column was able to separate fruit, leaf and root extracts into six, five and five fractions, respectively. The results showed that all the fractions tested exhibited considerably high antioxidative activity in the ferric thiocyanate assay and thiobarbituric acid test and the activities of some of the fractions were as good as those of either tocopherol or BHT. The fractions from different parts of the plants were found to contain different amounts of total phenolic compounds, which, interestingly, do not correspond to the antioxidative activity measured. This is probably due to the presence of different phenolics in the samples, with different antioxidative activities which involves various mechanisms inhibiting the oxidation process. The study suggested that root, leaf and fruit of M. citrifolia might contribute significantly to exogenous antioxidant which is crucial in combating oxidative stress.     

Isolation and synergism of in vitro anti-inflammatory and quinone reductase (QR) inducing agents from the fruits of Morinda citrifolia (noni)

The tropical fruits and fruit products of Morinda citrifolia, commonly known as noni, are consumed as a food or dietary supplement with purported health benefits. The objective of this study was to investigate the potential anti-inflammatory and cancer preventive effects of noni fruit puree extracts. Bioassay-guided fractionation of an ethyl acetate (EtOAc) extract of noni, comprising ~ 2% noni puree solids, led to the isolation of scopoletin (1), rutin (2), and quercetin (3). Quantitative HPLC analysis of the EtOAc extract revealed levels (dry weight basis) of scopoletin at 0.62 ??mol/g, quercetin at 0.26 ??mol/g and rutin at 0.045 ??mol/g. Scopoletin and quercetin inhibited the production of nitric oxide (NO) in a concentration-dependent manner in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells and exhibited quinone reductase (QR) induction in cultured Hepa 1c1c7 cells. Increases in QR activity in induced cells were associated with increases in QR protein as confirmed by Western blots. Combinations of scopoletin and quercetin at a low (< 10 ??M) concentration resulted in synergistic suppression in nitric oxide (NO) production and down-regulated inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expressions in LPS-induced RAW 264.7 macrophage cells. These results suggest that the combinations of noni compounds with different groups of chemical structures might be useful to efficiently suppress inflammatory and carcinogenic processes related to iNOS and COX-2 gene overexpression. These findings may provide some basis for the purported in vitro anti-inflammatory and anti-cancer effects of noni fruits as functional foods and dietary supplements.     

Quantification of coumarin derivatives in Noni (Morinda citrifolia) and their contribution of quenching effect on reactive oxygen species

The quantification of coumarin derivatives such as scopoletin, 7-hydroxycoumarin (7-HC) and 4-hydroxycoumarin (4-HC) in Noni (Morinda citrifolia) was described. The coumarin derivatives were determined by HPLC-UV or -fluorescence detection. More than 95% of peak purity for coumarin derivatives in Noni sample was confirmed by a multi-wavelength fluorescence detector. Amounts of scopoletin and 7-HC in Noni juices (A–H) were ranging 5.1–231 μg/ml and 0.04–0.45 μg/ml, respectively (n = 12). No 4-HC was detected in any Noni samples examined.     

Inhibitory effect of anthraquinones isolated from the Noni (Morinda citrifolia) root on animal A-, B- and Y-families of DNA polymerases and human cancer cell proliferation

During the course of our studies to develop new uses for the Noni (Morinda citrifolia) root, 10 anthraquinones, rubiadin (1), rubiadin 1-methyl ether (2), lucidin (3), damnacanthol (4), 1,3-dihydroxy-2-methoxymethylanthraquinone (5), 3-hydroxy-1-methoxy-2-methoxymethylanthraquinone (6), nordamnacanthal (7), damnacanthal (8), sorandidiol (9) and morindone (10), were isolated. Compounds 5, 6, 7, 8 and 10 exhibited remarkable inhibition against the activities of animal pols, and compound 10 was the strongest inhibitor in the anthraquinones investigated. Among mammalian pols, compound 10 inhibited the pol activities of A- (pol γ), B- (pols α, δ and ε) and Y- (pols η, ι and κ) families, but did not influence the activities of X-family pols (pols β, λ and terminal deoxynucleotidyl transferase). The tendency of pol inhibition showed a positive correlation with the suppression of human colon cancer cell HCT116 growth. These results suggested that the Noni root containing anthraquinones may be used as an anticancer functional food.     

Total phenolics,ascorbic acid,and antioxidant capacity of noni (Morinda citrifolia L.) juice and powder as affected by illumination during storage

Total phenolics, ascorbic acid, and antioxidant capacity of noni (Morinda citrifolia L.) juice and powder were determined during storage at 24 °C. After 2 weeks of storage, illuminated noni juice lost 32% of total phenolics, 89% of ascorbic acid, and 46–65% of antioxidant capacity—about 8%, 22%, and 9–15% more than unilluminated juice. Both illuminated and unilluminated juice lost 97% of ascorbic acid by 4 weeks. The difference in antioxidant characteristics between illuminated and unilluminated juice became insignificant at 12 weeks. After 12 weeks, illuminated noni powder lost 21% of total phenolics, 17% of ascorbic acid, and 23–36% of antioxidant capacity—about 13%, 4%, and 7–19% more than the unilluminated powder. Noni powder in brown bottles retained antioxidant characteristics significantly greater than that in clear bottles. Protection from light effectively reduced degradation of antioxidant characteristics of noni juice for only 2 weeks but those of noni powder for at least 3 months.     

Effects of binary solvent extraction system,extraction time and extraction temperature on phenolic antioxidants and antioxidant capacity from mengkudu (Morinda citrifolia)

An investigation into the effects of ethanol concentration (0–100%, v/v), extraction time (20–120 min) and extraction temperature (25–65 °C) on the extraction of phenolic antioxidants from mengkudu (Morinda citrifolia) was performed using a single-factor experiment. Total phenolic content (TPC) and total flavonoid content (TFC) assays were used for determination of phenolic compounds. Antioxidant capacity was evaluated by measuring the scavenging effect on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radicals. Experimental results showed that extraction conditions had significant effect on extraction of phenolic compounds and antioxidant capacities. The optimised conditions were 40% ethanol for 80 min at 65 °C, with values of 919.95 mg GAE/100 g DW for TPC, 472.73 mg CE/100 g DW for TFC, 791.71 μmol TEAC/100 g DW for ABTS and 1928.5 μmol TEAC/100 g DW for DPPH. TPC was significantly correlated with DPPH under the effects of ethanol concentration (r = 0.932) and extraction time (r = −0.938).     

Integrated management of insect vectors of Aspergillus flavus in stored maize, using synthetic antioxidants and natural phytochemicals

The purpose of this study was to investigate the insecticidal activity of two benzoic acids 2(3)-tert-butyl-4 hydroxyanisole (BHA) and 2,6-di(tert-butyl)-p-cresol (BHT); two phenolic acids 3-phenyl-2-propenoic acid (CA) and trans-4-hydroxy-3-methoxycinnamic acid (FA) and two essential oils of Eugenia caryophyllata (clove tree) and Thymus vulgaris (thyme) against Sitophilus zeamais, Tribolium confusum and Rhyzopertha dominica, vector carriers of aflatoxigenic fungi in stored maize. The susceptibility of insects, the frequency of isolation of Aspergillus section Flavi in insects and maize, and the analysis of aflatoxin B₁ in maize were determined. BHA, BHT, BHA/BHT mixture and the natural phytochemicals AF and AF/AC mixture showed the highest insecticidal activity against S. zeamais, T. confusum and R. dominica after 120 days of incubation. The insecticidal efficacy of the volatile fraction of essential oils of clove and thyme showed less inhibition. There was no contamination of Aspergillus section Flavi in dead and live insects collected from maize treated with BHA. No aflatoxin B₁ accumulation was detected in the control and treatments. The information obtained shows that these substances have the potential to control pest insect vectors of aflatoxigenic fungi in stored maize in microcosms during 120 days.     

A bacteriocin-like substance produced from Lactobacillus pentosus 39 is a natural antagonist for the control of Aeromonas hydrophila and Listeria monocytogenes in fresh salmon fillets

We studied the ability of Lactobacillus pentosus 39, a BLS (Bacteriocin-like substance)-producing strain, to control the growth of Aeromonas hydrophila ATCC 14715 and Listeria monocytogenes ATCC 19117 artificially added to fresh salmon fillets at refrigeration temperatures and under simulated cold-chain break conditions.At refrigeration temperatures, Lb. pentosus 39 protective culture and its putative bacteriocin significantly reduced A. hydrophila counts compared with the control (2.1 and 1.4 log CFU/g reductions, respectively). Similar behaviour was observed for L. monocytogenes (3.6 and 1.3 log CFU/g reductions, respectively).Under simulated cold-chain break conditions, an increase in temperature (30°C for 12h) produced an evident increase in the development of A. hydrophila, L. monocytogenes, but also of Lb. pentosus 39, with a consequent increase in BLS production. This condition resulted in a greater reduction of both pathogens compared with samples stored at 4°C throughout the experiment (2.8 log CFU/g reduction for A. hydrophila, 5.8 log CFU/g reduction for L. monocytogenes). In samples treated with the putative bacteriocin alone, a less marked decrease was observed.Our study demonstrates the capability of Lb. pentosus 39 to control the growth of psychrotrophic bacteria in an experimental seafood model system. A similar biopreservation technology could provide more prolonged shelf-life during storage of ready-to-eat seafood, ensuring safety, even under extreme conditions.     

Antioxidant activity of Camellia sinensis leaves and tea from a lowland plantation in Malaysia

Methanol extracts of fresh tea leaves from a lowland plantation in Malaysia were screened for total phenolic content (TPC) and antioxidant activity (AOA). AOA evaluation included 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging ability, ferric-reducing antioxidant power (FRAP), and ferrous-ion chelating (FIC) ability. Ranking, based on TPC and AOA, was as follows: shoots > young leaves > mature leaves. TPC and AOA of lowland leaves were comparable to those of highland plants. A green tea produced by drying young leaves in a household microwave oven for 4 min showed significantly higher TPC and AOA than did four commercial brands of green and black tea.     

Diversity of culturable microorganisms and occurrence of Listeria monocytogenes and Salmonella spp. in Tuber aestivum and Tuber melanosporum ascocarps

The aim of this study was to investigate the total mesophilic microorganisms, Pseudomonas genus, Enterobacteriaceae family, mold and yeast counts and the presence of Listeria monocytogenes and Salmonella spp on Tuber aestivum and Tuber melanosporum ascocarps. The results confirmed that the major percentage of the microorganisms, approximately 9.0 log ufc/g, were present in the peridium, the glebas of healthy truffles being practically free of microorganisms. The predominant microbial group was the Pseudomonas averaging 8.3 and 8.4 log cfu/g on T. aestivum and T. melanosporum whole ascocarps, respectively. The Enterobacteriaceae also achieved high populations, especially in T. aestivum truffles, with 6.3 log cfu/g. Molds and yeasts never exceeded 5.0 log cfu/g. The characterization of the isolates revealed that the fluorescens pseudomonads were the most prevalent. Raoultella terrigena and Enterobacter intermedius were the dominant Enterobacteriaceae. The identification of the yeast isolates revealed five species: Debaryomyces hansenii, Issatchenkia scutulata, Rhodotorula aurantiaca, Saccharomyces dairensis and Trichosporon beigelii subspecies A and B. The mold genera detected in both species of truffles were Aspergillus, Cladosporium, Penicillium and Fusarium, Trichoderma being present only in T. aestivum. L. monocytogenes was found in 10% of the samples of T. aestivum analysed but Salmonella spp. was not detected. Knowledge of the microbial population in terms of possible food borne and pathogen microorganisms is very useful for establishing successful disinfection and storage methods to prolong the shelf-life of ascocarps of T. aestivum and T. melanosporum.     

Biogenic amines formation in Streptococcus thermophilus isolated from home-made natural yogurt

Twelve different biogenic amines formation in 58 isolates of Streptococcus thermophilus from home-made natural yogurt were investigated in histidine (HDB) and lysine decarboxylase broth (LDB). All S. thermophilus isolates had an ability to produce twelve different biogenic amines in HDB and LDB. Most of the S. thermophilus isolates formed low amounts of histamine (1–50 mg/L) from histidine. Apart from one isolate, S. thermophilus produced tyramine at low (47 isolates) and medium (10 isolates) levels. The amount of each specific biogenic amine produced by S. thermophilus was generally lower than 100 mg L⁻¹. Also, the presence of hdcA gene was investigated using PCR technique and relation between gene and histamine production was conducted in S. thermophilus isolates. This study showed that most of the S. thermophilus isolates have the ability to form biogenic amines, especially histamine, and tyramine, which is an important consideration when selecting strains as starter cultures.     

Short communication: Biofilm production characterization of mecA and mecC methicillin-resistant Staphylococcus aureus isolated from bovine milk in Great Britain

Staphylococcus aureus is an important cause of contagious intramammary infection in dairy cattle, and the ability to produce biofilm is considered to be an important virulence property in the pathogenesis of mastitis. The aim of this study was to characterize the biofilm formation capacity of methicillin-resistant Staph. aureus (MRSA), encoding mecA or mecC, isolated from bulk tank milk in Great Britain. For this purpose, 20 MRSA isolates were grown on microtiter plates to determine the biofilm production. Moreover, the spa-typing and the presence of the intercellular adhesion genes icaA and icaD were analyzed by PCR. All MRSA isolates tested belonged to 9 spa-types and were PCR-positive for the ica genes; 10 of them (50%) produced biofilm in the microtiter plate assay. This is also the first demonstration of biofilm production by mecC MRSA.     

Elaboration of a probiotic oblea from whey fermented using Lactobacillus acidophilus or Bifidobacterium infantis

A novel probiotic product was developed, which was formulated as an oblea (wafer-type dehydrated traditional Mexican dessert) using goat sweet whey fermented with Bifidobacterium infantis or Lactobacillus acidophilus. To obtain the probiotic oblea, the fermented whey was formulated with prebiotic carbohydrates (inulin and resistant starch) and gelatin, and the preparation was poured onto a polytetrafluoroethylene-coated nonstick baking pan, dried in a convection oven, and finally dehydrated at a low relative humidity and room temperature (23 ± 2°C). The amounts of prebiotic carbohydrates and gelatin to be used in the formulation were determined by a factorial experimental design. An untrained sensory panel evaluated 3 quality characteristics (film formation, homogeneity, and smoothness) in the final product. Three different drying temperatures were tested, namely, 40, 55, and 70°C. Bacterial survival at each temperature was determined by viable plate-counting. The best formulation, based on the quality characteristics tested, consisted of 58.33% (vol/vol) of fermented whey, 8.33% (vol/vol) of 6% (wt/vol) resistant starch dispersion, 16.66% (vol/vol) of 15% (wt/vol) inulin solution, and 16.66% (vol/vol) of a 10% (wt/vol) gelatin solution. Drying at 55 ± 2°C for 2.66 ± 0.22 h allowed for concentrations of probiotic bacteria above 9 log₁₀ cfu/g, which is above the minimum concentration required in a probiotic product.     

Simultaneous analysis of purine alkaloids and catechins in Camellia sinensis, Camellia ptilophylla and Camellia assamica var. kucha by HPLC

Simultaneous analysis of purine alkaloids and catechins in tea from dry leaves of Camellia sinensis, Camellia ptilophylla and Camellia assamica var. kucha by a reversed-phase high-performance liquid chromatography (RP-HPLC) method. This HPLC method had been proved to be appropriate for the identification and quantification of purine alkaloids and catechins, and exhibited good correlation coefficients, detection levels and recovery rates. Caffeine, theobromine, theacrine, (+)-catechin, (−)-epicatechin, (−)-epigallocatechin, (−)-epigallocatechin gallate, (−)-epicatechin gallate, (−)-gallocatechin gallate and (−)-gallocatechin were identified and quantified in the three species of genus Camellia Sect. Thea. There was 2.72% caffeine and 0.26% theobromine in C. sinensis, 4.85% theobromine in C. ptilophylla, and 1.58% theacrine, 0.94% caffeine and 0.45% theobromine in C. assamica var. kucha. Theacrine in C. sinensis and C. ptilophylla, and caffeine in C. ptilophylla were not detected. These data highlight differences in the relative proportions of purine alkaloids in the three species of Camellia Sect. Thea. In addition, different catechins were identified and quantified. The highest content of catechin in dry leaves was (−)-epigallocatechin gallate (EGCG) 3.51%, (−)-gallocatechin gallate (GCG) 9.88% and (−)-epigallocatechin gallate (EGCG) 6.78% in C. sinensis, C. ptilophylla and C. assamica var. kucha, respectively.     

Enhanced heavy metal phytoextraction by Echinochloa crus-galli using root exudates

Heavy metal uptake and growth by Echinochloa crus-galli were investigated to determine if the use of root exudates enhanced phytoextraction. E. crus-galli were planted in soils contaminated with 600 mg kg^− 1 Pb, 40 mg kg^− 1 Cd and 100 mg kg^− 1 Cu. E. crus-galli were then cultivated with and without root exudates from Belamcanda chinensis for 4 weeks. The growth of E. crus-galli in metal-contaminated soils that contained root exudates showed increased roots and shoots when compared to E. crus-galli grown without root exudates (p < 0.05). In addition, the accumulation of metal in E. crus-galli that was cultivated with the root exudates was two- to fourfold higher than in plants that were cultivated without the root exudates. The exchangeable soil fraction in the rhizosphere of E. crus-galli grown with root exudates was greater than when E. crus-galli was grown without root exudates. Finally, the BCF and TF values of Cd, Cu and Pb were greater when the root exudates were added (p < 0.05). Taken together, these results indicate that root exudates can be used as a natural chelating agent to enhance phytoextraction.     

Essential oils of the aerial parts of three Salvia species from Jordan: Salvia lanigera, S. spinosa and S. syriaca

The compositions of the essential oils of three Jordanian Salvia species, S. lanigera and S. spinosa from a desert climate, and S. syriaca from a Mediterranean habitat, were studied. All three oils are rich in monoterpene derivatives (68–73%).     

Characterisation of catechins in green and black teas using square-wave voltammetry and RP-HPLC-ECD

Eight green and three black teas have been analysed using square-wave voltammetry at a glassy-carbon electrode, at pH 2 and square-wave frequency 100 Hz. The SWV response of teas consisted of two partially resolved anodic peaks: peak 1 at around 0.372 V, and peak 2 around 0.491 V. First anodic peak was due to oxidation of pyrogallol catechins, i.e. epigallocatechin gallate (EGCG) and epigallocatechin (EGC), and peak 2 can be associated with oxidation of ortho-hydroquinone and galloyl groups in catechins, gallic acid, theaflavins, and other catechol-type phenolics present in tea. Peak 1 has been chosen for quantification purposes, and concentrations of catechins were calculated from the calibration plot constructed for EGC used as external standard. Amounts of catechins in green teas obtained by SWV were in good agreement with those obtained using reverse-phase high-performance liquid chromatography with electrochemical detection (RP-HPLC-ECD). For black tea samples the detector response of peak 1 was diminished due to interferences of coexisting polyphenols, and SWV obtained results were something lower than those obtained by HPLC-ECD.     

Short communication: Recovery of viable Mycobacterium avium subspecies paratuberculosis from retail pasteurized whole milk in Brazil

Mycobacterium avium ssp. paratuberculosis (MAP) is the etiological agent of paratuberculosis, a chronic granulomatous enteritis that affects all ruminants worldwide. Some researchers have indicated a possible role of MAP in Crohn's disease. Despite extensive research and large and important advances in the past few decades, the etiology of Crohn's disease remains indefinite. The most probable transmission route of MAP from animals to humans is milk and dairy products. Mycobacterium avium ssp. paratuberculosis has already been detected in milk samples worldwide, and some studies have reported that MAP is resistant to pasteurization. In Brazil, MAP has been reported in raw milk samples; however, Brazilian retail pasteurized milk has not yet been tested for viable MAP. The aim of this study was to investigate MAP in pasteurized milk in the region of Viçosa (Minas Gerais, Brazil). Thirty-seven samples were collected and processed for culture of MAP. One colony similar to MAP was observed and confirmed by IS900-nested PCR and sequencing. Analysis revealed 97 to 99% identity with the MAP K-10 strain. This study is the first report of the presence of MAP in retail pasteurized whole milk in Brazil.     

Characterisation of esterolytic activity from two wild mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum

Characterisation of esterase activities from the edible mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum, were investigated. Native electrophoresis of the crude extracts prepared from both mushroom samples showed the presence of esterolytic activities. The extracts had the greatest activity in the presence of p-nitrophenyl butyrate (pNPB) as a substrate. pH and temperature optima were found to be 8.0 and 30 °C for both enzymes, respectively. V_max and K_m values were determined as 14.2 U/l and 71 μM for A. vaginata var. vaginata and 34.6 U/l and 9.6 μM for T. terreum, respectively. The pH-stability profile showed a stationary line between 3.0 and 10.0 for both enzymes. The esterolytic activities from the extracts were maintained between 10 and 40 °C for 4 h and started to decrease at 50 °C. The effects of EDTA, NaN₃, DTT and PMSF on the enzyme activity were also investigated.