Bioaccessibility of polyphenols from selected cereal grains and legumes as influenced by food acidulants.

BACKGROUND: Polyphenols in food are valued for their health-beneficial influences. Food acidulants lime juice and amchur used in Indian cookery were evaluated for their influence on polyphenol bioaccessibility from food grains. RESULTS: Lime juice increased bioaccessible flavonoids by 25% in roasted finger millet, while there was no change in total bioaccessible polyphenols in pressure-cooked, open-pan-boiled and roasted finger millet in the presence of food acidulants. Addition of amchur to pressure-cooked and microwave-heated pearl millet increased bioaccessible flavonoids by 30 and 53% respectively, while lime juice increased them by 46% in pressure-cooked pearl millet. Increased bioaccessibility of specific phenolic acids from finger millet and pearl millet was observed upon addition of these food acidulants. The presence of either lime juice or amchur increased bioaccessible flavonoids from both legumes studied. Addition of lime juice and amchur, however, exerted a negative effect on the bioaccessibility of several phenolic compounds from food grains in native state and under certain processing conditions. CONCLUSION: Thus food acidulants lime juice and amchur had a significant influence on the bioaccessibility of health-beneficial phenolic compounds from food grains. Use of food acidulants in food preparations could be a strategy to enhance the bioavailability of polyphenols, especially flavonoids from grains. © 2016 Society of Chemical Industry.

Application of a Cu-chitosan/multiwalled carbon nanotube film-modified electrode for the sensitive determination of rutin.

A new sensitive electrochemical sensor, a glassy carbon electrode modified with chemically cross-linked copper-complexed chitosan/multiwalled carbon nanotubes (Cu-CS/MWCNT/GCE), for rutin analysis was constructed. Experimental investigations of the influence of several parameters showed that the rutin can effectively accumulate on the surface of the Cu-CS/MWCNT/GCE, which accumulation caused a pair of well-defined redox peaks in the electrochemical signal when measurements were carried out in Britton-Robinson buffer solution (pH 3, 0.04 M). The surface of the Cu-CS/MWCNT/GCE was characterized by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry analysis. In a rutin concentration range of 0.05-100 µM and under optimized conditions, a linear relationship between the oxidation peak current of rutin and its concentration was obtained with a detection limit of 0.01 µM. The Cu-CS/MWCNT/GCE showed good selectivity, stability, and reproducibility. Moreover, the sensor was used to determine the presence of rutin in fruits with satisfactory results.

Enhanced inhibition of Aspergillus niger on sedge (Lepironia articulata) treated with heat-cured lime oil.

AIMS: This study aimed to examine heat curing effect (30-100°C) on antifungal activities of lime oil and its components (limonene, p-cymene, ß-pinene and α-pinene) at concentrations ranging from 100 to 300 µl ml(-1) against Aspergillus niger in microbiological medium and to optimize heat curing of lime oil for efficient mould control on sedge (Lepironia articulata). METHODS AND RESULTS: Broth dilution method was employed to determine lime oil minimum inhibitory concentration, which was at 90 µl ml(-1) with heat curing at 70°C. Limonene, a main component of lime oil, was an agent responsible for temperature dependencies of lime oil activities observed. Response surface methodology was used to construct the mathematical model describing a time period of zero mould growth on sedge as functions of heat curing temperature and lime oil concentration. Heat curing of 90 µl ml(-1) lime oil at 70°C extended a period of zero mould growth on sedge to 18 weeks under moist conditions. CONCLUSIONS: Heat curing at 70°C best enhanced antifungal activity of lime oil against A. niger both in medium and on sedge. SIGNIFICANCE AND IMPACT OF THE STUDY: Heat curing of lime oil has potential to be used to enhance the antifungal safety of sedge products.

5-Geranyloxy-7-methoxycoumarin inhibits colon cancer (SW480) cells growth by inducing apoptosis.

For the first time, three coumarins were isolated from the hexane extract of limes (Citrus aurantifolia) and purified by flash chromatography. The structures were identified by NMR (1D, 2D) and mass spectral analyses as 5-geranyloxy-7-methoxycoumarin, limettin, and isopimpinellin. These compounds inhibited human colon cancer (SW-480) cell proliferation, with 5-geranyloxy-7-methoxycoumarin showing the highest inhibition activity (67 %) at 25 µM. Suppression of SW480 cell proliferation by 5-geranyloxy-7-methoxycoumarin was associated with induction of apoptosis, as evidenced by annexin V staining and DNA fragmentation. In addition, 5-geranyloxy-7-methoxycoumarin arrested cells at the G0/G1 phase, and induction of apoptosis was demonstrated through the activation of tumour suppressor gene p53, caspase8/3, regulation of Bcl2, and inhibition of p38 MAPK phosphorylation. These findings suggest that 5-geranyloxy-7-methoxycoumarin has potential as a cancer preventive agent.

Effects of temperature and purity of magnesium sulfate during extraction of pesticide residues using the QuEChERS method.

Despite its many documented advantages, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation approach has problems with a few unstable pesticides, partly due to the exothermic reaction generated by the use of anhydrous magnesium sulfate (anh. MgSO4) during extraction. These pesticides also tend to be difficult to analyze by GC/MS. The aim of this study was to evaluate the effect of temperature during the extraction process in a revised version of AOAC Official Method 2007.01 using anh. MgSO4 > or = 99% (fine powder) or > or = 97% (granular) purity, and the use of an ice bath for particular unstable pesticides of interest (chlorothalonil, captan, captafol, folpet, and the degradation products cis-1,2,3,6-tetrahydrophthalimide and phthalimide). Recoveries of 38 representative pesticides were measured in limes and broccoli at different extraction conditions by LC/MS/MS and low-pressure GC/MS/MS. Results showed that the difference in temperature when using > or = 99% versus > or = 97% purity anh. MgSO4 was 6-9 degrees C, which did not lead to significant differences in recoveries. The use of an ice bath aided recovery for some of the analytes in broccoli, but no significant differences were observed for limes, which already provided greater stability of the base-sensitive analytes due to acidity of the matrix.

Chemical composition of hexane extract of Citrus aurantifolia and anti-Mycobacterium tuberculosis activity of some of its constituents.

The main aim of this study was to isolate and characterize the active compounds from the hexane extract of the fruit peels of Citrus aurantiifolia, which showed activity against one sensitive and three monoresistant (isoniazid, streptomycin or ethambutol) strains of Mycobacterium tuberculosis H37Rv. The active extract was fractionated by column chromatography, yielding the following major compounds: 5-geranyloxypsoralen (1); 5-geranyloxy-7-methoxycoumarin (2); 5,7-dimethoxycoumarin (3); 5-methoxypsoralen (4); and 5,8-dimethoxypsoralen (5). The structures of these compounds were elucidated by 1D and 2D NMR spectroscopy. In addition, GC-MS analysis of the hexane extract allowed the identification of 44 volatile compounds, being 5,7-dimethoxycoumarin (15.79%), 3-methyl-1,2-cyclopentanedione (8.27%), 1-methoxy-ciclohexene (8.0%), corylone (6.93%), palmitic acid (6.89%), 5,8-dimethoxypsoralen (6.08%), a-terpineol (5.97%), and umbelliferone (4.36%), the major constituents. Four isolated coumarins and 16 commercial compounds identified by GC-MS were tested against M. tuberculosis H37Rv and three multidrug-resistant M. tuberculosis strains using the Microplate Alamar Blue Assay. The constituents that showed activity against all strains were 5 (MICs = 25-50 mg/mL), 1 (MICs = 50-100 mg/mL), palmitic acid (MICs = 25-50 mg/mL), linoleic acid (MICs = 50-100 mg/mL), oleic acid (MICs = 100 mg/mL), 4-hexen-3-one (MICs = 50-100 mg/mL), and citral (MICs = 50-100 mg/mL). Compound 5 and palmitic acid were the most active ones. The antimycobacterial activity of the hexane extract of C. aurantifolia could be attributed to these compounds.

Evaluation of Citrus aurantifolia peel and leaves extracts for their chemical composition, antioxidant and anti-cholinesterase activities.

BACKGROUND: The replacement of synthetic antioxidants by safe natural antioxidants fosters research on the screening of vegetables and food as sources of new antioxidants. Moreover, oxidative degeneration of cells is associated with neurodegenerative diseases such as Alzheimer's disease. On the basis of these considerations this work aimed to investigate the antioxidant properties [by using the diphenyl picryl hydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing ability of plasma assays, and the ß-carotene bleaching test] and the anti-cholinesterase activity of Citrus aurantifolia peel and leaves from different areas of growth. RESULTS: Methanol extracts of the peel and leaves demonstrated the strongest radical scavenging activity. A similar trend was observed with the reducing ability, with values from 112.1 to 146.0 µmol L(-1) Fe(II) g(-1). The relationship between phenol and flavonoid contents and antioxidant activity was statistically investigated. Based on analysis by high-performance liquid chromatography, the most abundant flavonoids found in C. aurantifolia extracts were apigenin, rutin, quercetin, kaempferol and nobiletin. n-Hexane fractions of both peel and leaves showed a good acetylcholinesterase inhibitory activity with IC(50) values in the range 91.4-107.4 µg mL(-1). Gas chromatography-mass spectrometry analysis revealed the presence of monoterpenes and sesquiterpenes as most common components. CONCLUSION: The findings of this study suggest a potential use of C. aurantifolia peel and leaves for supplements for human health.

Antibacterial activity of natural spices on multiple drug resistant Escherichia coli isolated from drinking water, Bangladesh.

BACKGROUND: Spices traditionally have been used as coloring agents, flavoring agents, preservatives, food additives and medicine in Bangladesh. The present work aimed to find out the antimicrobial activity of natural spices on multi-drug resistant Escherichia coli isolates. METHODS: Anti-bacterial potentials of six crude plant extracts (Allium sativum, Zingiber officinale, Allium cepa, Coriandrum sativum, Piper nigrum and Citrus aurantifolia) were tested against five Escherichia coli isolated from potable water sources at kushtia, Bangladesh. RESULTS: All the bacterial isolates were susceptible to undiluted lime-juice. None of them were found to be susceptible against the aqueous extracts of garlic, onion, coriander, pepper and ginger alone. However, all the isolates were susceptible when subjected to 1:1:1 aqueous extract of lime, garlic and ginger. The highest inhibition zone was observed with lime (11 mm). CONCLUSION: Natural spices might have anti-bacterial activity against enteric pathogens and could be used for prevention of diarrheal diseases. Further evaluation is necessary.

[Study on technology in preparation of Fructus Auranti extract].

OBJECTIVE: To optimize the method of Fructus Auranti extracts preparation. METHOD: The extraction conditions and resin type were examined by using naringin as main indices. The sampling amount, the elution solvent and their flow rates were optimized. The recycling times and recovery capacity of resin were also studied. RESULT: The best extraction could be obtained by adding 10 times amount of NaOH (pH 11) for 3 times, 1 hour each time. The purification conditions were specified as follows: using D101 macroporous resin, the sampling ratio of resin weight to raw material was 1:0.8 with a flow rate of 2 BV x h(-1) and 4 BV 50% aqueous ethanol as elusion solven. CONCLUSION: By using this method, the naringin in the product could reach above 30%. Besides, the optimum method is simple and practical.

At-home methods for tenderizing meat using blade tenderization, lime juice and pineapple puree.

We evaluated at-home methods to tenderize flank steaks. Steaks sourced from a commercial beef processor were aged 28 d postmortem, prior to treatment application. Individual steaks were cut into four sampling portions and treated via blade tenderization (BT), and marination with lime juice (LJ) and/or pineapple puree (PP). Blade tenderization (2×) was conducted parallel and perpendicular to muscle fiber direction; LJ and PP were added at 25% of sample weight. Tenderness was assessed via Warner-Bratzler Shear Force (WBSF) and data was analyzed via mixed models. Neither the three-way interaction (P = 0.64), the BT x PP interaction (P = 0.19), nor LJ (P = 0.35) treatment altered WBSF. Blade tenderization x LJ (P = 0.09) and LJ x PP (P = 0.07) tended to alter WBSF. Blade tenderization (P = 0.03) and pineapple puree (P < 0.01) reduced WBSF by 2.40 and 4.50 N, respectively. WBSF was reduced by 7.3 to 24% via treatment combinations of LJ, BT, or PP.

Essential oil from Citrus aurantifolia prevents ketotifen-induced weight-gain in mice.

Obesity is a major health problem world-wide. Medical intervention is often needed to tackle this problem, and accordingly the need for developing more effective, safer and cheaper weight reducing drugs has become paramount in recent years. In the present study, the effects of lime (Citrus aurantifolia) essential oils in reducing body weight, individually and in co-administration with ketotifen, an antihistaminic drug that causes weight gain, has been investigated using a mouse model. During the 45 days experimental period, the mice that received ketotifen demonstrated an enhancement both in the amount of food intake and body weight compared with the control group. Groups treated with lime essential oil displayed a reduction in body weight and food consumption in mice, possibly through promoting anorexia which might have played a role in weight loss. Interestingly, co-administration of the lime essential oil and ketotifen caused significant suppression in gaining weight, as well as decreased body weights of mice. The data obtained in this study suggested that lime essential oil plays an important role in weight loss and could be useful in the treatment of drug-induced obesity and related diseases. The GC-MS analysis of the essential oils of C. aurantifolia was also performed and approximately 22 main components, with limonene (28.27%) being the principal one, were identified and quantified.

[Intestinal absorption properties of flavones and extract of fructus aurantii immaturus in rats].

OBJECTIVE: To investigate the intestinal absorption of naringin, hesperidin, neohesperidin and the extract of Fructus Aurantii Immaturus in rats. METHOD: The rat intestinal perfusion and enzymes incubation models were used, together with the determination of the n-octanol/water partition coefficient of the components (P). RESULT: In perfusion model, the P(eff) of all components were low, and the P(eff) of naringin, hesperidin and neohesperidin were 0.140-0.252, 0.156-0.268 and 0.154-0.285, respectively. In four different regions of intestine of rat and with different concentration, the P(eff) of the components both had no significant difference, whereas the P(eff) of the extract were higher than the P(eff) of the single component. The metabolite of components was not detected in intestine. The P of naringin, hesperidin and neohesperidin were 0.36, 0.40 and 0.48, respectively, and the pH of buffer solution had no influence to its distribution coefficient. CONCLUSION: Poor permeation contributed to the poor intestinal absorption of naringin, hesperidin and neohesperidin. The absorption of components in extract were increased, and the results suggest that the extract may enhance the intestinal absorption of the components.

[Analysis of volatile oil in Fructus Aurantii processed with Zhangband method by GC-MS].

OBJECTIVE: To analyze the chemical components of the volatile oil in processed pieces of Fructus Aurantii (PPFA) with JiangXi Zhangband methods by GC-MS. METHODS: The volatile oil was obtained from PPFA by steam distillation. The amount of the components from the volatile oil were determinated by area normalization method. The separated components were identified by GC-MS. RESULTS: Composed of the total volatile oil over 90% , 70 components were separated and identified. All of the processed Fructus Aurantii produced new chemical composition, in the meantime,the contents were changed in some chemical composition after processed. CONCLUSION: The method is reliable, stable and has good repeatability. This method can be applied to the analysis of volatile oil components in PPFA. It will provide the certain scientific methods for further evaluating of PPFA quality.

Phytophotodermatitis: bulla formation and hyperpigmentation during spring break.

Phytophotodermatitis is a phototoxic dermatologic reaction that occurs with exposure to ultraviolet light after contact with certain plant chemicals. Recognition is vital to proper management and avoidance of unnecessary distress for patients. Sun-sensitizing compounds, known as furocoumarins, are found in many plants (limes, celery, and natural grasses) and are excited by ultraviolet A (UVA) irradiation. UVA irradiation induces covalent linkages of nuclear DNA resulting in cutaneous photosensitivity and vesicular skin damage while increasing melanin production. Delayed erythema, hyperpigmentation, and vesicle or bullae formation are hallmarks. Literature review reveals most cases occur during or after vacation in a sunny destination with exposure to citrus fruit or in children playing outdoors in the summer when furocoumarins are abundant. Hyperpigmented lesions typically appear on the hands or around the mouth. Overall incidence is unknown and there appears to be no predilection for race, although typically more easily recognized in the fair skinned. Of concern are the many cases where misdiagnosis of child abuse has occurred with unnecessary legal action taken and emotional distress for innocent families. Phytophotodermatitis is relatively common and easily diagnosed with awareness and a careful history. Accurate diagnosis avoids unnecessary concern by patients and potential misdiagnosis of abuse. Consider phytophotodermatitis when hyperpigmentation in bizarre streaks on sun-exposed areas with vesicles in a nondermatomal distribution is present. Presented is an illustrative case.

Preclinical evaluation of lime juice as a topical microbicide candidate.

BACKGROUND: The continued growth of the global HIV epidemic highlights the urgent need to develop novel prevention strategies to reduce HIV transmission. The development of topical microbicides is likely to take a number of years before such a product would be widely available. This has resulted in a call for the rapid introduction of simpler vaginal intervention strategies in the interim period. One suggested practice would be vaginal douching with natural products including lime or lemon juice. Here we present a comprehensive preclinical evaluation of lime juice (LiJ) as a potential intervention strategy against HIV. RESULTS: Pre-treatment of HIV with LiJ demonstrated direct virucidal activity, with 10% juice inactivating the virus within 5 minutes. However, this activity was significantly reduced in the presence of seminal plasma, where inactivation required maintaining a 1:1 mixture of neat LiJ and seminal plasma for more than 5 minutes. Additionally, LiJ demonstrated both time and dose-dependent toxicity towards cervicovaginal epithelium, where exposure to 50% juice caused 75-90% toxicity within 5 minutes increasing to 95% by 30 minutes. Cervicovaginal epithelial cell monolayers were more susceptible to the effects of LiJ with 8.8% juice causing 50% toxicity after 5 minutes. Reconstructed stratified cervicovaginal epithelium appeared more resilient to LiJ toxicity with 30 minutes exposure to 50% LiJ having little effect on viability. However viability was reduced by 75% and 90% following 60 and 120 minutes exposure. Furthermore, repeat application (several times daily) of 25% LiJ caused 80-90% reduction in viability. CONCLUSION: These data demonstrate that the virucidal activity of LiJ is severely compromised in the presence of seminal plasma. Potentially, to be effective against HIV in vivo, women would need to apply a volume of neat LiJ equal to that of an ejaculate, and maintain this ratio vaginally for 5-30 minutes after ejaculation. Data presented here suggest that this would have significant adverse effects on the genital mucosa. These data raise serious questions about the plausibility and safety of such a prevention approach.

Leaves of Citrus aurantifolia exhibit a different sensibility to solar UV-B radiation according to development stage in relation to photosynthetic pigments and UV-B absorbing compounds production.

Plants of Citrus aurantifolia grown in a greenhouse without solar UV radiation (UVR) were transferred outdoors to evaluate the effect of solar UV-B radiation (UVBR, 280-315 nm) in prior-developed leaves, constituted by apical bud and those fully expanded before being taken outdoors, and post-developed leaves, formed by those expanded outdoors. Results demonstrated that over a 40 d outdoor period leaf chlorophyll content and distribution pattern were different with and without solar UVBR. Chlorophyll a, chlorophyll b and total chlorophyll contents in both treatments were higher in prior-developed leaves than in post-developed ones. However, highest values were observed in prior-developed leaves under solar UVBR, whereas in post-developed leaves an opposite trend was observed. Carotenoids content in prior-developed leaves was higher with solar UVBR, whereas in post-developed leaves there were no significant differences in both with and without solar UVBR. In addition, prior-developed leaves under solar UVBR accumulated flavonoids, but not anthocyanins. Growth parameters (e.g. DW, DW/FW ratio, LMA, plant height, length and width of foliar lamina) did not show significant differences between plants grown with and without solar UVBR. Thus, our results demonstrated that C. aurantifolia leaves exhibited a different sensibility to solar UVBR according to development stage in relation to photosynthetic pigments and UV-B absorbing compounds production. In addition, the solar UVBR was not necessary as inductor of photosynthetic protection mechanisms in a short-time growth period. On the other hand, our results also demonstrated that solar UVBR acted as an effective feeding deterrent against citrus leafminer.

HPLC-PDA-MS and NMR characterization of C-glycosyl flavones in a hydroalcoholic extract of Citrus aurantifolia leaves with antiplatelet activity.

A hydroalcoholic extract of lime ( Citrus aurantifolia) leaves has been developed in Cuba to be used as a nutritional supplement and phytomedicine in the form of tincture (TLL). A HPLC-PDA-ESI/MS/MS method has been used for the comprehensive analysis of C-glycosyl flavones in TLL. Six C-glycosyl flavones were characterized and, to confirm the proposed structures and to elucidate the nature of the sugar units, a preparative procedure was applied, and isolated compounds were characterized by NMR. Apigenin-6,8-di-C-beta-D-glucopyranoside (vicenin II) (1), diosmetin-6,8-di- C-beta- d-glucopyranoside (2), apigenin-8-C-beta-D-glucopyranoside (vitexin) (3), apigenin-8-C-[alpha-L-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (4), apigenin-6-C-[alpha-l-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (5). and apigenin-6-C-beta-D-glucopyranoside (isovitexin) (6) were identified in TLL and quantified by HPLC-PDA. Compounds 4 and 5 were two new arabinosyl derivatives of vitexin and isovitexin. Inhibitor effect of TLL on platelet aggregation induced by physiological agonists of platelets was evaluated in human plasma. TLL inhibited significantly ADP and epinephrine-induced platelet aggregation in a concentration-dependent manner (IC 50=0.40 and 0.32 mg/mL, respectively).

Stability of lime essential oil microparticles produced with protein-carbohydrate blends.

The objective of this work was to analyze the influence of maltodextrin equivalent dextrose on the lime essential oil reconstitution, storage, release and protection properties. Four treatments were evaluated: whey protein concentrate (WPC), and blends of maltodextrin with dextrose equivalents of 5 (WM5), 10 (WM10) and 20 (WM20). The reconstitution and storage properties of the microparticles (solubility, wettability and density), water kinetics adsorption, sorption isotherms, thermogravimetric properties, controlled release and degradation kinetics of encapsulated lime essential oil were studied to measure the quality of the encapsulated materials. The results of the study indicated that the DE degree influences the characteristics of reconstitution, storage, controlled release and degradation characteristics of encapsulated bioactive compounds. The increase in dextrose equivalent improves microparticle solubility, wettability and density, mainly due to the size of the maltodextrin molecules. The adsorption kinetics and sorption isotherm curves confirmed the increase in the hygroscopicity of maltodextrins with higher degrees of polymerization. The size of the maltodextrin chains influenced the release and protection of the encapsulated lime essential oil. Finally, the maltodextrin polymerization degree can be considered a parameter that will influence the physicochemical properties of microencapsulated food.