Phenolic content, antioxidant, anti-inflammatory and anticancer activities of the edible halophyte Suaeda fruticosa Forssk

Suaeda fruticosa is an edible and medicinal halophyte known for its hypoglycaemic and hypolipidaemic activities. In this study, novel biological activities of the shoot extracts related to their phenolics were investigated. Results showed an appreciable total phenolic (31.8 mg GAE/g DW) in shoot extracts. The estimation of antioxidant capacities using oxygen radical absorbance capacity (ORAC method) and a cell based-assay (WS1) of four extracts (hexane, dichloromethane, methanol and water) showed that shoot methanol extract exhibit the highest antioxidant activities. The same extract displayed the utmost anti-inflammatory activity, inhibiting nitric oxide (NO) release, by 66.4% at 160 μg/ml in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Besides, the dichloromethane extract showed the highest anticancer activity against human lung carcinoma (A-549) and colon adenocarcinoma cell lines (DLD-1, Caco-2 and HT-29) with specificity against DLD-1 (IC₅₀ = 10 ± 1 μg/ml). These findings demonstrate the remarkable potentiality of this edible halophyte as valuable source of antioxidants which exhibit original and interesting anti-inflammatory and anticancer capacities.     

Antioxidant and free radical scavenging activities of wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) in Taiwan

Momordica charantia Linn. var. abbreviata Ser. (Cucurbitaceae), also known as “Shan Ku Gua”, is a wild variety of bitter melon (BM) in Taiwan. The size of its fruits is only about one-fifth of the commonly seen BM. It is commonly consumed as vegetable and also used as a popular folk medicine. In this study, the antioxidant and free radical scavenging activities of BM aqueous (BM-H₂O) and ethanol (BM-EtOH) extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelation, cytochrome c and xanthine oxidase inhibition (XOI) assays, as well as FeCl₂-ascorbic acid induced lipid peroxidation (thiobarbituric acid reactive substances, TBARS) assay in rat liver homogenates in vitro. Total flavonoid and phenol contents of BM extracts were also analyzed. Results showed that both BM-H₂O (IC₅₀=129.94 μg/ml) and BM-EtOH (IC₅₀=156.78 μg/ml) possess potent DPPH radical scavenging activity, which was better than vitamin E (IC₅₀=172.21 μg/ml). These extracts also showed better iron chelating activity than vitamin E. However, they were weaker than vitamin E in free radical scavenging, xanthine oxidase inhibitory and anti-lipid peroxidation activities. With the exception of XOI activity [IC₅₀=7.90 μg/ml (BM-H₂O) vs. 7.69 μg/ml (BM-EtOH)], BM-H₂O showed a lower IC₅₀ value in free radical scavenging [IC₅₀=6.15 μg/ml (BM-H₂O) vs. 7.08 μg/ml (BM-EtOH)] and anti-lipid peroxidation [IC₅₀=53.72 μg/ml (BM-H₂O) vs. 88.51 μg/ml (BM-EtOH) for liver; 82.53 μg/ml (BM-H₂O) vs. 91.83 μg/ml (BM-EtOH) for brain] activities than BM-EtOH. Both BM extracts showed a weak anti-lipid peroxidation activity in plasma. BM-H₂O (62.0 mg/g) possessed a significant higher concentration of total flavonoids than BM-EtOH (44.0 mg/g), but was lower in the total phenol content (BM-H₂O: 51.6 mg/g vs. BM-EtOH: 68.8 mg/g). In conclusion, BM extracts possess potent antioxidant and free radical scavenging activities. These antioxidant activities could have contributed, at least partly, to the therapeutic benefits of the certain traditional claims of wild BM.     

Inhibitory effect of raspberries on starch digestive enzyme and their antioxidant properties and phenolic composition

Seven primocane fall-bearing raspberry (Rubus idaeus L.) cultivars, Nova (red), Dinkum (red), Heritage (red), Autumn Britten (red), Josephine, Anne (yellow), Fall Gold (yellow) were analysed for potential health promoting properties including their inhibitory effect on starch and fat digestive enzymes, antioxidant activities, and phenolic composition. The tested raspberry extracts showed no detectable inhibition of pancreatic α-amylase and lipase. However, all the extracts exhibited potent inhibition of α-glucosidase with IC₅₀ from 16.8 to 34.2 μg/mL. Four phenolic compounds, ellagic acid, cyanidin-diglucoside, pelargonidin-3-rutinoside, and catechin were identified as the active α-glucosidase inhibitors. The raspberry extracts also possessed significant antioxidant activities with oxygen radical absorbance capacities (ORAC) ranging from 136.7 to 205.2 μmol Trolox equivalents (TE)/g dry weight fruit and DPPH radical scavenging activities from 305 to 351 μmol TE/g. The total phenolic content of raspberry cultivars varied significantly from 40.9 to 98.5 mg of gallic acid equivalents/g dry weight. The anthocyanin content varied widely from 0.1 to 9.5 mg cyanidin 3-glucoside equivalents/g. Nine phenolic acids were quantified in raspberries and their total amounts varied from 157.3 to 713.5 μg/g. The enzyme inhibition and antioxidant properties of raspberry cultivars were not correlated with their total phenolic, anthocyanin, and phenolic acid content. Overall, ‘Dinkum’ and ‘Josephine’ raspberry varieties possess higher total phenolic content, ORAC, DPPH radical scavenging activity, and α-glucosidase inhibitory activity than other five cultivars.     

Rapid isolation of geraniin from Nephelium lappaceum rind waste and its anti-hyperglycemic activity

Recently we confirmed the ability of ethanolic Nephelium lappaceum L. rind extract to act as anti-hyperglycemic agent. Geraniin, an ellagitannin, was identified as the major bioactive compound isolated from the ethanolic Nephelium lappaceum L. rind extract. In this study, we describe the rapid isolation of geraniin from the above plant. In addition to its extremely high anti-oxidant activity and low pro-oxidant capability, geraniin is seen to possess in vitro hypoglycemic activity (alpha-glucosidase inhibition: IC₅₀ = 0.92 μg/ml and alpha-amylase inhibition: IC₅₀ = 0.93 μg/ml), aldol reductase inhibition activity (IC₅₀ = 7 μg/ml) and has the ability to prevent the formation of advanced glycation end-products (AGE). Geraniin was observed to exhibit these properties at more significant levels compared to the positive controls acarbose (carbohydrate hydrolysis inhibitor), quercetin (aldol reductase inhibitor) and green tea (AGE inhibitor). Geraniin therefore, has the potential to be developed into an anti-hyperglycemic agent. Our findings also strongly support the use of a geraniin-standardised N. lappaceum extract in the management of hyperglycemia.     

Inhibitory effect of Chardonnay and black raspberry seed extracts on lipid oxidation in fish oil and their radical scavenging and antimicrobial properties

Ethanol extracts of Chardonnay grape and black raspberry seed flours were evaluated for their capacity to suppress lipid oxidation, preserve important fatty acids, and inhibit microbial growth. They were also tested for radical scavenging activity against DPPH and peroxyl radicals as reflected in oxygen radical absorbance capacity (ORAC), and total phenolic content (TPC). Both tested seed flour extracts suppressed lipid oxidation and rancidity development in fish oil. Black raspberry seed flour extract significantly reduced the degradation of biologically important n − 3 PUFA under accelerated oxidative conditions. Black raspberry and Chardonnay seed flour extracts at 165 and 160 μg seed flour equivalents/mL, respectively exhibited bacteriocidal activity against Escherichia coli and growth inhibition of Listeria monocytogenes under experimental conditions. Both seed flour extracts exhibited DPPH radical quenching activity and Chardonnay had the stronger ORAC of 663 μmol Trolox equivalents per gram seed flour and the higher TPC of 99 mg gallic acid equivalents/g flour. The data from this study suggest the potential for developing natural food preservatives from these seed flours for improving food stability, quality, safety, and consumer acceptance.     

The protective ability of Mediterranean dietary plants against the oxidative damage: The role of radical oxygen species in inflammation and the polyphenol,flavonoid and sterol contents

Ten hydroalcoholic extracts of edible plants from the Calabria region (Italy) were evaluated for their in vitro antioxidant and antiradical properties and in vivo topical anti-inflammatory activity. All the extracts had radical-scavenging and/or antioxidant properties, the most active plants being hawkweed oxtongue and viper’s bugloss. The best free radical (DPPH·)-scavenging activity was found in hawkweed oxtongue and chicory leaves extracts (IC₅₀ = 25 and 26 μg/ml, respectively). Hawkweed oxtongue, poppy and viper’s bugloss extracts showed the greatest inhibition of linoleic acid oxidation (IC₅₀ = 3 μg/ml). Viper’s bugloss and hawkweed oxtongue extracts had the greatest antioxidant effect on bovine brain peroxidation (IC₅₀ = 11 and 22 μg/ml). All the extracts also showed an anti-inflammatory effect: 300 μg/cm² provoked oedema reductions ranging from 18% to 43%. Cress was the most active plant. Chicory leaves contained the highest amount of phenolics (190 mg/g) whilst Rush crimps contained the highest amount of flavonoids (32.9 mg/g), followed by hawkweed oxtongue (15.8 mg/g). Cress contained the highest number of sterols. Among them, γ-sitosterol (12.2%) and ergost-5-en-3-ol (3β) (4.5%) were found to be the major constituents. Moreover, three of the identified molecules (stigmasta-5,23-dien-3β-ol, stigmasta-5,24(28)-dien-3-ol (3β,22E) and 9,19-cyclolanost-24-en-3-ol (3β)) were found in this plant only.     

Fermentative behavior of Saccharomyces strains during microvinification of raspberry juice (Rubus idaeus L.)

Sixteen different strains of Saccharomyces cerevisiae and Saccharomyces bayanus were evaluated in the production of raspberry fruit wine. Raspberry juice sugar concentrations were adjusted to 16°Brix with a sucrose solution, and batch fermentations were performed at 22 °C. Various kinetic parameters, such as the conversion factors of the substrates into ethanol (Y_p/s), biomass (Y_x/s), glycerol (Y_g/s) and acetic acid (Y_ac/s), the volumetric productivity of ethanol (Q_p), the biomass productivity (P_x), and the fermentation efficiency (E_f) were calculated. Volatile compounds (alcohols, ethyl esters, acetates of higher alcohols and volatile fatty acids) were determined by gas chromatography (GC-FID). The highest values for the E_f, Y_p/s, Y_g/s, and Y_x/s parameters were obtained when strains commonly used in the fuel ethanol industry (S. cerevisiae PE-2, BG, SA, CAT-1, and VR-1) were used to ferment raspberry juice. S. cerevisiae strain UFLA FW 15, isolated from fruit, displayed similar results. Twenty-one volatile compounds were identified in raspberry wines. The highest concentrations of total volatile compounds were found in wines produced with S. cerevisiae strains UFLA FW 15 (87,435 μg/L), CAT-1 (80,317.01 μg/L), VR-1 (67,573.99 μg/L) and S. bayanus CBS 1505 (71,660.32 μg/L). The highest concentrations of ethyl esters were 454.33 μg/L, 440.33 μg/L and 438 μg/L for S. cerevisiae strains UFLA FW 15, VR-1 and BG, respectively. Similar to concentrations of ethyl esters, the highest concentrations of acetates (1927.67 μg/L) and higher alcohols (83,996.33 μg/L) were produced in raspberry wine from S. cerevisiae UFLA FW 15. The maximum concentration of volatile fatty acids was found in raspberry wine produced by S. cerevisiae strain VR-1. We conclude that S. cerevisiae strain UFLA FW 15 fermented raspberry juice and produced a fruit wine with low concentrations of acids and high concentrations of acetates, higher alcohols and ethyl esters.     

Wheat bran lipophilic compounds with in vitro anticancer effects

Wheat bran has been widely recognised as a cancer preventive agent, although the mechanism of the protection is not yet fully understood. Some reports suggested that, for the protection, lipophilic phytochemicals from the bran were more important than the physiological function of bran fibre. Wheat bran lipophilic extracts were scrutinised using bioactivity-guided fractionation (HPLC) against the growth of human prostate adenocarcinoma (PC3) cells. The fractions containing unsaturated free fatty acid, phytosteroids and alkylresorcinols exerted high cytotoxic activity. Detailed research of the alkylresorcinol fraction isolated seven pure compounds, four of them with strong inhibitory properties against the growth of PC3 cells, including 5-heptadecylresorcinol (IC₅₀ = 22.5 μg/ml), 5-(16-heneicosenyl)resorcinol (trans) (IC₅₀ = 13.7 μg/ml), 5-(14-nonadecenyl)resorcinol (trans) (IC₅₀ = 42.2 μg/ml) and 5-(2-oxotricosanyl)resorcinol (IC₅₀ = 10.9 μg/ml). The alkylresorcinols in wheat bran were quantified using a Single Ion Monitoring (SIM) method developed on LC-MS. The active alkylresorcinols were found to be minor components in wheat bran, however, they exerted higher cytotoxic effects on cancer cells than the positive control chlorambucil (IC₅₀ = 58.7 μg/ml). This research suggested that alkylresorcinols are important for the cancer preventive activity of wheat bran. Other lipophilic compounds such as some free unsaturated fatty acids and phytosteroids may also contribute to the anticancer activity.     

Antioxidant capacities of Gundelia tournefortii L. extracts and inhibition on glutathione-S-transferase activity

Gundelia tournefortii L. is an important food source and a well-known medicinal plant in Eastern Anatolia. Therapeutic effects of medicinal plants are known to be closely related to their antioxidant capacities. Antioxidant activities of G. tournefortii, both for the aerial parts and seeds, were investigated by using both 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation inhibition methods. The seeds were found to have higher antioxidant potential than the aerial, with IC₅₀ values of 0.073 mg/mL for DPPH scavenging and 0.146 mg/mL for lipid peroxidation inhibition capacities. In addition, total phenolic contents of the Gundelia tournefortii L. extracts, especially the seed extracts correlates to its high antioxidant activity with 105.1 ± 8.7 μg gallic acid equivalents (GAEs) per mg of seed extract. Plant extracts with high phenolics content are known to have important effects on various enzymes, as well as glutathione-S-transferases, which are important detoxification enzymes in phase II systems with an important role in developing multi-drug resistance to chemotherapy in tumour cells. Consequently, the effects of G. tournefortii extracts on crude cytosolic glutathione-S-transferase was also studied and the seed extracts have shown effective inhibition of cytosolic GST activity, with an IC₅₀ of 97.51 μg/mL.     

Antioxidant and free radical-scavenging activities of seeds and agri-wastes of some varieties of soybean (Glycine max)

In order to find antioxidant potential, seeds of 30 varieties of Glycine max were studied for their total phenolic contents (TPC), flavonoids and antioxidant activity (AOA). The seed extracts showed wide variation of TPC from 6.4 to 81.7 mg GAE/g, flavonoids 3.5 to 44.6 mg QE/g and AOA 7.5% to 74.7%. Free radical-scavenging activity (FRSA), assayed by DPPH in terms of IC₅₀ (inhibitory concentration), ranged from 0.14 to 0.80 mg/ml, EC₅₀ (efficiency concentration) from 6.1 to 34.8 mg/mg DPPH, ARP (anti-radical power) 2.9 to 16.4 and reducing power from 1.9 to 4.7 ASE/ml. Variety Kalitur showed highest the FRSA followed by Alankar and Hara soya, as evident from their low IC₅₀, EC₅₀ and high ARP values. Alankar, Kalitur NRC-37, PK-472, VLS-47, Hara soya varieties were with comparatively higher TPC (52.7–81.7 mg GAE/g), AOA (50.5–74.7%) and showed better inhibition of peroxide formation assayed through ammonium thiocyanate and egg yolk, non-site-specific and site-specific inhibition of hydroxyl radical induced deoxyribose degradation and ferrous ion-chelating capacity than did the other varieties. Seed extracts of these varieties and leaves of Kalitur showed significant protection against DNA damage caused by free radicals. The agri-wastes of some promising varieties, e.g. Alankar, Kalitur, NRC-37 and PK-472, showed TPC ranging from 27.4 to 167 mg GAE/g, total flavanoids from 10.4 to 63.8 mg QE/g and AOA from 26.5% to 84.7% and their values were highest in the leaves, followed by pod pericarp and twigs. Out of all the varieties studied, leaves of Alankar and Kalitur varieties were more potent free radical-scavengers than were seeds, pod pericarp or twigs. The specific phenolic compositions and their quantifications were performed by HPLC and MS/MS, which showed that the seeds of Kalitur were higher in genistin (127 μg/g), seeds and leaves of Alankar in diadzin (113 μg/g) and gallic acid (87.2 μg/g), respectively. The present studies may be of importance in varietal improvement, nutraceuticals, bio-pharmaceuticals and utilization of agri-wastes as possible cost-effective natural antioxidants.     

In vitro activity of the essential oils of Origanum vulgare, Satureja montana and their main constituents in peroxynitrite-induced oxidative processes

The essential oil obtained from aerial parts of Satureja montana L. and Origanum vulgare L. (Labiatae) along with four of its main components, p-cymene, carvacrol, thymol and γ-terpinene were tested in models of in vitro peroxynitrite-induced formation of both 3-nitrotyrosine and malondialdehyde, two biomarkers of the oxidative stress of recognised pathological and toxicological significance. The essential oils showed a significant activity, thus decreasing 3-nitrotyrosine formation (IC₅₀ values of 43.9 μg/ml for S. montana and 19.2 μg/ml for O. vulgare), and also inhibited the peroxynitrite induced malondialdehyde formation (IC₅₀ values of 27.2 μg/ml and 17.0 μg/ml respectively). Thymol and carvacrol inhibited 3-nitrotyrosine formation (IC₅₀ values of 81.3 μM and 106.3 μM; ascorbic acid IC₅₀ = 400 μM) and reduced malondialdehyde formation (IC₅₀ values of 43.9 μM and 70.1 μM respectively; trolox IC₅₀ = 240 μM). On the contrary, p-cymene and γ-terpinene were completely inactive in both assays under the concentration of 300 μg/ml. These results support, in particular for origanum, the nutraceutical value of these spices and the potential of thymol and carvacrol in preventing the formation of toxic products by the action of reactive nitrogen species.     

Comparison of antioxidant capacities and cytotoxicities of certain fruit peels

This work was undertaken to explore the potential of fruit waste materials as sources of powerful natural antioxidants. The peels of eight kinds of fruits commonly consumed and grown in Thailand were used. The ethanolic fruit peel extracts were subjected to the scavenging tests of DPPH and ABTS radicals. Results from both assays were in good agreement that the top three markedly high free radical-scavenging power was from the peel extracts of Punica granatum (pomegranate), Nephelium lappaceum (rambutan), and Garcinia mangostana (mangosteen). The IC₅₀ values to quench the DPPH free radicals of these three extracts were 0.003, 0.006, and 0.023 mg/ml and the trolox equivalent antioxidant capacity (TEAC) values from ABTS assay were 4.066, 3.074, and 3.001 mM/mg, respectively. The extract of mangosteen peel showed moderate toxicity to Caco-2 cells and high toxicity to peripheral blood mononuclear cells (PBMC) with the IC₅₀ values of 32.0 and 4.9 μg/ml, respectively. Pomegranate peel extract stimulated Caco-2 cell and PBMC proliferation with the ED₅₀ of 4.7 and 44.4 μg/ml, respectively. Peel extract of rambutan exhibited extremely high value of IC₅₀ (>100 μg/ml) against both cell types indicating non-toxic activity to the cells. It was concluded that the peel of rambutan may be considered potentially useful as a source of natural antioxidants for food or drug product because of its high antioxidant activity and non-toxic property to normal cells.     

Immunomodulatory and anticancer activities of phenolics from emblica fruit (Phyllanthus emblica L.)

There is a paucity of studies on the immunomodulatory properties of fruit extracts of emblica with the emphasis on lymphocytes. Therefore, the aim of the study was to evaluate the immunomodulatory properties and anticancer potential of six phenolic compounds from emblica fruit by in vitro proliferation assay. Effects of these compounds on splenocyte proliferation and the cytotoxicity to both human breast cancer cell (MCF-7) and human embryonic lung fibroblast cell (HELF) were determined by the MTT method. Significantly stimulatory effects (P < 0.05) were found for geraniin and isocorilagin. The concentration of geraniin, quercetin 3-β-d-glucopyranoside, kaempferol 3-β-d-glucopyranoside, isocorilagin, quercetin, kaempferol and rutin to obtain 50% of stimulatory effect was 56, 123, 242, 42, 73, 93 and 92 μg/ml, respectively. The assay of anticancer activities suggested that geraniin and isocorilagin exhibited higher cytotoxicities than other compounds against MCF-7 with IC₅₀ of 13.2 and 80.9 μg/ml, respectively. Isocorilagin exhibited a strong cytotoxicity to HELF cell with IC₅₀ of 51.4 μg/ml. Geraniin, quercetin, kaempferol and their glycosides had weak cytotoxicity against HELF cells. Paclitaxel showed a strong cytotoxicity to MCF-7 and HELF with IC₅₀ of 6.8 and 14.5 μg/ml, respectively. These findings are in line with the reported potent antioxidant activity. These results suggested that the antitumour activity of these compounds might be achieved by immunomodulatory properties which could partially be attributed to their antioxidant activity.     

Phenolic compounds in cowpea and horse gram flours in comparison to chickpea flour: Evaluation of their antioxidant and enzyme inhibitory properties associated with hyperglycemia and hypertension

Evaluation of phenolic contents and their in vitro bioactive functional properties of cowpea and horse gram flours in comparison to chickpea flour revealed that horse gram flour, which contain highest concentrations of total phenolics and total flavonoids was found to be the most active 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenger. Hydrogen peroxide scavenging capacity, reducing power and metal chelating abilities were significantly higher in cowpea and horse gram than chickpea flour. Phenolic extracts from flours showed distinct variations in the inhibition of enzymes associated with hyperglycemia and hypertension. Although, α-glucosidase inhibitory activity was superior in cowpea (IC₅₀ 52.8 μg/ml), α-amylase (IC₅₀ 96.4 μg/ml) and angiotensin-I converting enzyme (IC₅₀ 32.8 μg/ml) inhibitory activities were predominant in horse gram. These results provided useful information for effective utilisation of legume flours as ingredients in composite flours and for the development of food products with health promoting functions.     

Antioxidant and protective properties of six Tanacetum species against hydrogen peroxide-induced oxidative stress in K562 cell line: A comparative study

The antioxidant activities of ethanolic extract of six species of Tanacetum (T. budjnurdense, T. hololeucum, T. chiliophyllum, T. sonboli, T. tabrisianum, T. kotschyi) from Iran were examined by employing various established in vitro assay systems. The results showed that all Tanacetum extracts displayed antioxidant activities, with IC₅₀ values ranging from 59.55 to 157.24 μg/ml, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The extract of T. hololeucum, with an IC₅₀ value of 59.55 μg/ml was nearly two or three times more active than the other used Tanacetum extracts. The amounts of total phenolics and total flavonoids were also determined by spectrophotometer. A similar order of the amounts of phenolics and flavonoids in all plant extracts were found. The results showed that the extent of antioxidant activities is in accordance with the amounts of phenolics and flavonoids existing in all plant extracts. Regarding high performance liquid chromatography (HPLC) data, caffeic acid, ferulic acid, luteolin, apigenin and rutin were detected as major phenolic compounds in all the species investigated. Pretreatment of K562 cells with various concentrations of Tanacetum extracts (10–100 μg/ml) for 16 h prevent cell damage and enhanced activity of antioxidant enzymes induced by a treatment with H₂O₂. Moreover, lower level of glutathione caused by hydrogen peroxide in K562 cells were partly recovered by a pretreatment of cells with various Tanacetum species extract. These results may show the significant protection effect of Tanacetum sp. against oxidation of the cells.     

The influence of fruit ripening on the phytochemical content and biological activity of Capsicum chinense Jacq. cv Habanero

During the past decade, it has been reported that the consumption of certain foods and spices such as pepper may have a positive effect on health. The present study evaluates the influence of fruit ripening on total phenols, flavonoids, carotenoids and capsaicinoids content and antioxidant, hypoglycaemic and anticholinesterase activities of Capsicum chinense Jacq. cv Habanero. The chemical investigation showed a different composition between the two stages of ripening (immature and mature). Generally, the concentration of carotenoids and capsaicinoids increased as the peppers reached maturity, whereas the concentration of phenols declined. The immature fruits showed the highest radical scavenging activity (IC₅₀ of 97.14 μg/ml). On the contrary, the antioxidant activity evaluated by the β-carotene bleaching test showed a significant activity for mature peppers (IC₅₀ value of 4.57 μg/ml after 30 min of incubation). Mature peppers inhibited α-amylase with an IC₅₀ of 130.67 μg/ml. The lipophilic fractions of both mature and immature peppers exhibited an interesting and selective inhibitory activity against α-amylase with IC₅₀ values of 29.58 and 9.88 μg/ml, respectively. Both total extracts of mature and immature peppers inhibited butyrylcholinesterase selectively. The obtained results underline the potential health benefits as a result of consuming C. chinense Habanero and suggest that it could be used as new valuable flavour with functional properties for food or nutriceutical products on the basis of the high content of phytochemicals and found biological properties.     

Identification of polyphenols in tobacco leaf and their antioxidant and antimicrobial activities

Crude polyphenols were extracted from tobacco leaf by 80% ethanol solution with ultrasonic treatment and then purified by a macroporous resin. The polyphenols from tobacco leaf (PTL) were subjected to analyses by reverse-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS). The dominant polyphenols in tobacco leaf were identified as chlorogenic acid and rutin. Furthermore, the antioxidant activities of PTL were investigated, including scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (5.02 μg/ml IC₅₀ value), hydroxyl radicals (49.6 μg/ml IC50 value) and superoxide anion radicals (44.0 μg/ml IC₅₀ value), inhibition activity of lipid peroxidation (132 μg/ml IC₅₀ value) and reducing power. The proliferation inhibition activities on Escherichia coli, Staphylococcus aureus and Bacillus subtilis were also measured for evaluating the antimicrobial activity of PTL. The diameters of inhibition zones were 20.23 ± 0.42, 17.66 ± 0.86 and 12.89 ± 0.29 mm, respectively. The results showed that PTL had great potential as antioxidant and antimicrobial agent.     

Novel angiotensin I-converting enzyme inhibitory peptides derived from soya milk

Inhibitors of angiotensin I-converting enzyme (ACE) are useful in treating hypertension, and many have been derived from food products, including soybeans. Using the industrial protease PROTIN SD-NY10, we developed a processed soya milk (PSM) with enhanced ACE inhibitory activity. The ACE inhibitory activity of PSM (IC₅₀ = 0.26 μg/ml) was greater than that of regular soya milk (IC₅₀ = 8.75 μg/ml). Eight novel ACE inhibitory peptides were purified from PSM by reversed-phase chromatography: FFYY (IC₅₀,1.9 μM), WHP (4.8 μM), FVP (10.1 μM), LHPGDAQR (10.3 μM), IAV (27.0 μM), VNP (32.5 μM), LEPP (100.1 μM), and WNPR (880.0 μM). The IC₅₀ values of these peptides are comparable to those reported for other ACE inhibitory peptides derived from wheat, chicken, bonito, wine, etc. Due to the relatively low IC₅₀ values of several peptides identified in this study, they may serve as ideal base components of food supplements for patients with hypertension.     

The inhibitory effects of ethanol extracts from sorghum,foxtail millet and proso millet on α-glucosidase and α-amylase activities

Cereal crops have recently experienced increased interest due to their potential health benefits. It has been suggested that the intake of whole grain foods is beneficial to the prevention and management of diabetes mellitus. In this study, we investigated the inhibitory effect of 70% EtOH extracts from different cultivars of sorghum, foxtail millet and proso millet on α-glucosidase and α-amylase. Among the six sorghum cultivars, Mongdang-susu(SS-1), Me-susu(SS-2), Susongsaengi-susu(SS-3) and Sikyung-susu(SS-4) extracts exhibited higher inhibitory activities against α-glucosidase (IC₅₀ = 1.1–1.4 μg/ml) than acarbose, reference inhibitor (IC₅₀ = 2.1 μg/ml). In addition, these extracts strongly inhibited degradation of starch by pancreatic and salivary α-amylase, whereas extracts from foxtail and proso millets exhibited no visible or detectible inhibitory effect on α-amylase or on α-glucosidase activity. These in vitro studies indicate the potential of sorghum in the development of effective anti-diabetic agents.