Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.)

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.     

Antimicrobial and antioxidant activities of Melissa officinalis L. (Lamiaceae) essential oil

The present study describes antimicrobial and free radical scavenging capacity (RSC) together with the effects on lipid peroxidation (LP) of Melissa officinalis essential oil. The chemical profile of essential oil was evaluated by the means of gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). RSC was assessed measuring the scavenging activity of essential oil on the 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) and OH(*) radicals. The effect on LP was evaluated following the activities on Fe(2+)/ascorbate and Fe(2+)/H(2)O(2) systems of induction. The antimicrobial activity was tested against 13 bacterial strains and six fungi. The examined essential oil exhibited very strong RSC, reducing the DPPH radical formation (IC(50) = 7.58 microg/mL) and OH radical generation (IC(50) = 1.74 microg/mL) in a dose-dependent manner. According to the GC-MS and TLC (dot-blot techniques), the most powerful scavenging compounds were monoterpene aldehydes and ketones (neral/geranial, citronellal, isomenthone, and menthone) and mono- and sesquiterpene hydrocarbons (E-caryophyllene). Very strong inhibition of LP, particularly in the Fe(2+)/H(2)O(2) system of induction (94.59% for 2.13 microg/mL), was observed in both cases, also in a dose-dependent manner. The most effective antibacterial activity was expressed on a multiresistant strain of Shigella sonei. A significant rate of antifungal activity was exhibited on Trichophyton species.     

Content, composition, and bioactivity of the essential oils of three basil genotypes as a function of harvesting

A study was conducted to evaluate the effect of cut on biomass productivity, oil content, composition, and bioactivity of Ocimum basilicum L. (cvs. German and Mesten) and Ocimum sanctum L. (syn. O. tenuiflorum L.) (cv. Local) in Mississippi. Yields of basil herbage and essential oil were high and comparable to those reported in the literature. Essential oil content of O. basilicum cv. German varied from 0.40 to 0.75%, the oil content of cv. Mesten varied from 0.50 to 0.72%, and the oil content of cv. Local (of O. sanctum) ranged from 0.17 to 0.50% in air-dried basil. Herbage and essential oil yields of cvs. German and Mesten of O. basilicum increased with the second and then again with the third cut, whereas herbage and oil yields of cv. Local of O. sanctum increased with the third cut relative to the previous cuts. Overall, essential oil yields were 115, 123, and 51 kg/ha for the cvs. German, Mesten, and Local, respectively. The major oil constituents of cvs. German and Mesten (of O. basilicum) were (-)-linalool (30-40%) and eugenol (8-30%), whereas the major oil constituents of cv. Local (of O. sanctum) were eugenol (8-43%) and methylchavicol (15-27%). Essential oils from both species grown in Mississippi showed in vitro activity against Leishmania donovani (IC50 = 37.3-49.6 microg/mL), which was comparable to the activity of commercial oil (IC50 = 40-50 microg/mL). Minor basil oil constituents (+)-delta-cadinene, 3-carene, alpha-humulene, citral, and (-)- trans-caryophyllene had antileishmanial activity, whereas other constituents were ineffective. None of the oil was cytotoxic to mammalian cells.     

Evaluation of the dietetic and therapeutic potential of a high molecular weight hydroxycinnamate-derived polymer from Symphytum asperum Lepech. Regarding its antioxidant, antilipoperoxidant, antiinflammatory, and cytotoxic properties

A water-soluble hydroxycinnamate-derived polymer (>1000 kDa) from Symphytum asperum Lepech. (Boraginaceae) strongly reduced the diphenylpicrylhydrazyl radical (IC(50) approximately 0.7 microg/mL) and inhibited the nonenzymatic lipid peroxidation of bovine brain extracts (IC(50) approximately 10 ng). This polymer exhibited only a low hydroxyl radical scavenging effect in the Fe(3+)-EDTA-H(2)O(2) deoxyribose system (IC(50) > 100 microg/mL) but strongly decreased superoxide anion generation in either the reaction of phenazine methosulfate with NADH and molecular oxygen (IC(50) approximately 13.4 microg/mL) or in rat PMA-activated leukocytes (IC(50) approximately 5 microg/mL). The ability to inhibit both degranulation of azurophil granules and superoxide generation in primed leukocytes indicates that the NADPH oxidase responsible for this later effect is inhibited, pointing to the Symphytum asperum polymer as a potent antiinflammatory and vasoprotective agent. At all concentrations tested (0-200 microg/mL), we observed no cytotoxicity on normal human fibroblasts and neither antiproliferative effects nor proliferation activation on neoplastic cells.     

Antimicrobial and antioxidant properties of rosemary and sage (Rosmarinus officinalis L. and Salvia officinalis L., Lamiaceae) essential oils

The essential oils of rosemary ( Rosmarinus officinalis L.) and sage ( Salvia officinalis L.) were analyzed by means of gas chromatography-mass spectrometry and assayed for their antimicrobial and antioxidant activities. Antimicrobial activity was tested against 13 bacterial strains and 6 fungi, including Candida albicans and 5 dermatomycetes. The most important antibacterial activity of both essential oils was expressed on Escherichia coli, Salmonella typhi, S. enteritidis, and Shigella sonei. A significant rate of antifungal activity, especially of essential oil of rosemary, was also exhibited. Antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with the effect on lipid peroxidation (LP). RSC was assessed by measuring the scavenging activity of essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH) and hydroxyl radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H2O2 systems of induction. Investigated essential oils reduced the DPPH radical formation (IC50 = 3.82 microg/mL for rosemary and 1.78 microg/mL for sage) in a dose-dependent manner. Strong inhibition of LP in both systems of induction was especially observed for the essential oil of rosemary.     

Chemical composition and antifungal activity of essential oils from different tissues of Japanese Cedar (Cryptomeria japonica)

In this study antifungal activities of essential oils from different tissues of Japanese cedar (Cryptomeria japonica D. Don) against four wood decay fungi and six tree pathogenic fungi were investigated. In addition, the yields of essential oils obtained by water distillation were compared and their constituents determined by GC-MS analyses. The yield of essential oils from four tissues of Japanese cedar is in the decreasing order of leaf (27.38 mL/kg) > bark (6.31 mL/kg) > heartwood (3.80 mL/kg) > sapwood (1.27 mL/kg). Results obtained from the antifungal tests demonstrate that the essential oil of Japanese cedar heartwood used against Laetiporus sulphureus and Trametes versicolor and sapwood essential oil used against L. sulphureus had strong antifungal activities at 500 mug/mL, with IC(50) values of 39, 91, and 94 microg/mL, respectively. Besides, the essential oils of Japanese cedar heartwood used against Rhizoctonia solani, Collectotrichum gloeosporioides, Fusarium solani, and Ganoderma australe had strong antifungal activities at 500 microg/mL, with IC(50) values of 65, 80, 80, and 110 microg/mL, respectively. GC-MS analyses showed that the sesquiterpene hydrocarbon compounds dominate in the essential oil from Japanese cedar heartwood, amounting to a total percentage of 82.56%, with the major compounds of delta-cadinene (18.60%), isoledene (12.41%), and gamma-muurolene (11.82%). It is proposed that the excellent antifungal activities of Japanese cedar heartwood essential oils might correlate with the presence of these compounds.     

Inhibition of gastric H(+),K(+)-ATPase and Helicobacter pylori growth by phenolic antioxidants of Curcuma amada

Gastric ulcer is the most prevalent gastrointestinal disorder, resulting from oxidative stress, Helicobacter pylori infection, up-regulation of proton potassium ATPase (PPA) activity, down-regulation of gastric mucosal defense, etc. In this paper it is reported that phenolic fractions of Curcuma amada, commonly known as mango ginger, acted as potent inhibitors of PPA and H. pylori growth. Mango ginger free phenolics (MGFP) and mango ginger bound phenolics (MGBP) inhibited PPA at IC50 values of 2.2 +/- 0.21 and 0.7 +/- 0.08 microg/mL, respectively, exhibiting 9-27-fold better potency over lansoprazole (IC(50) of 19.3 +/- 2.2 microg/mL). MGFP is constituted by caffeic (26%), gentisic (24%), ferulic (20%), gallic (10%), cinnamic (7%), and protocatechuic acids (7%) and MGBP by ferulic (47%), cinnamic (29%), p-coumaric acid (11%), and syringic (5%) acids as major phenolic acids. MGFP and MGBP further exhibited free radical scavenging (IC(50) of 2.2 +/- 0.17 and 4.2 +/- 0.36 microg/mL), reducing power abilities (193-104 units/g), inhibition of lipid peroxidation (IC(50) of 10.3 +/- 0.91 and 15.6 +/- 1.6 microg/mL), and DNA protection (80% at 4 microg), indicating strong antioxidative properties. MGFP and MGBP thus may be potential and inexpensive multistep blockers against ulcers.     

Bioactive metabolites from the fungus Nectria galligena, the main apple canker agent in Chile

The phytopathogenic fungus Nectria galligena Bres. is the most common canker disease agent of hardwood trees. The terpenoids colletochlorin B, colletorin B, ilicicolin C, E, and F, as well as the phytotoxin alpha,beta-dehydrocurvularin have been isolated from liquid cultures of N. galligena obtained from the xylem of infected apple trees in central Chile. Ilicicolin C and F and alpha,beta-dehydrocurvularin were active against Pseudomonas syringae with IC50 values of 28.5, 28.5, and 14.2 microg/mL, respectively, in the same range as streptomycin and penicillin G (11 and 15 microg/mL, respectively). All of the compounds showed moderate inhibitory activity toward the enzymes acetylcholinesterase (AChE) and beta-glucuronidase. The most active enzyme inhibitors were colletochlorin B and ilicicolin C and E, with IC50 values of 30-36 microg/mL in the AChE assay and 32-43 microg/mL in the beta-glucuronidase test. All of the chlorinated compounds showed some toxicity toward human lung fibroblasts, with IC50 values in the range of 64-120 microg/mL. alpha,beta-Dehydrocurvularin proved to be the most toxic compound, showing IC50 values less than 12 microg/mL. The effect of the isolated compounds on seed germination and radicle and epicotyl growth was assessed in lettuce and millet seeds. At 100 and 200 microg/disk, alpha,beta-dehydrocurvularin significantly reduced radicle length and epicotyl growth in Lactuca sativa. This is the first report on the occurrence of colletochlorin B, colletorin B, ilicicolin C, E, and F, as well as alpha,beta-dehydrocurvularin associated to N. galligena.     

Characterization of the volatile composition of essential oils of some lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils

The essential oils of Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. were analyzed by means of gas chromatography-mass spectrometry and assayed for their antioxidant and antimicrobial activities. The antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with effects on lipid peroxidation (LP). RSC was assessed measuring the scavenging activity of the essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH(*)) and OH(*) radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H(2)O(2) systems of induction. Essential oils exhibited very strong RSCs, reducing the DPPH radical formation (IC(50)) in the range from 0.17 (oregano) to 0.39 microg/mL (basil). The essential oil of T. vulgaris exhibited the highest OH radical scavenging activity, although none of the examined essential oils reached 50% of neutralization (IC(50)). All of the tested essential oils strongly inhibited LP, induced either by Fe(2+)/ascorbate or by Fe(2+)/H(2)O(2). The antimicrobial activity was tested against 13 bacterial strains and six fungi. The most effective antibacterial activity was expressed by the essential oil of oregano, even on multiresistant strains of Pseudomonas aeruginosa and Escherichia coli. A significant rate of antifungal activity of all of the examined essential oils was also exhibited.     

Effect of maturation on the composition and biological activity of the essential oil of a commercially important Satureja species from Turkey: Satureja cuneifolia Ten. (Lamiaceae)

The essential oil obtained by hydrodistillation from aerial parts of Satureja cuneifolia Ten., collected in three different maturation stages such as preflowering, flowering, and postflowering, were analyzed simultaneously by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Thymol (42.5-45.2%), p-cymene (19.4-24.3%), and carvacrol (8.5-13.2%) were identified as the main constituent in all stages. At the same time, the essential oils and main components were evaluated for their antimicrobial activity using a microdilution assay resulting in the inhibition of a number of common human pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and the yeasts Candida albicans and Candida tropicalis. The minimum inhibitory concentrations (MIC) varied between 62.5 and 250 microg/mL within a moderate antimicrobial activity range. Furthermore, the antioxidant capacity of the essential oils and major components thymol and carvacrol were examined in vitro. The essential oils obtained from S. cuneifolia in three different stages and its main components were interacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH (*)) as a nitrogen-centered stable radical, resulting in IC 50 = 1.6-2.1 mg/mL. In addition, the effects on inhibition of lipid peroxidation of the essential oils were assayed using the beta-carotene bleaching method. All of the tested oils inhibited the linoleic acid peroxidation at almost the same level as butylated hydroxytoluene (BHT) (93.54-94.65%). BHT and ascorbic acid were used as positive controls in the antioxidant assays.     

Crocetin, dimethylcrocetin, and safranal bind human serum albumin: stability and antioxidative properties

Crocetin (CRT) and dimethylcrocetin (DMCRT) are derived from crocins which are found in the stigmas of saffron (Crocus sativus L.), while safranal is the main component of saffron's essential oil. The aim of the present study was to examine their interaction with human serum albumin in aqueous solution at physiological conditions using constant protein concentration and various ligand contents. FT-IR and UV-visible spectroscopic methods were used to determine the ligands' binding mode, the binding constant, and the effects of ligand complexation on protein secondary structure. Structural analysis showed that crocetin, dimethylcrocetin, and safranal bind nonspecifically (H-bonding) via protein polar groups with binding constants of Kcrt =2.05 (+/-0.30) x 103 M-1, Kdmcrt = 9.60 (+/-0.35) x 104 M-1, and Ksaf = 2.11 (+/-0.35) x 103 M-1. The protein secondary structure showed no major alterations at low ligand concentrations (1 microM), whereas at higher content (1 mM), decrease of alpha-helix from 55% (free HSA) to 43-45% and increase of beta-sheet from 17% (free HSA) to 18-22% and random coil 7% (free HSA) to 10-14% occurred in the ligand-HSA complexes. The results point to a partial unfolding of protein secondary structure at high ligand content. The antioxidant activity of CRT, DMCRT, and safranal was also tested by the DPPH* antioxidant activity assay, and their IC50 values were compared to that of well-known antioxidants such as Trolox and butylated hydroxy toluene (BHT). The IC50 values of CRT and safranal were 17.8 +/- 1 microg/mL and 95 +/- 1 microg/mL, respectively, while the inhibition of DMCRT reached a point of 38.8%, which corresponds to a concentration of 40 microg/mL, and then started to decrease. The IC50 values of Trolox and BHT were 5.2 +/- 1 microg/mL and 5.3 +/- 1 microg/mL, respectively.     

Inhibitory effects of oolong tea polyphenols on pancreatic lipase in vitro

Fifty-four polyphenols isolated from tea leaves were evaluated for their inhibitory activities against pancreatic lipase, the key enzyme of lipid absorption in the gut. (-)-Epigallocatechin 3-O-gallate (EGCG), which is one of major polyphenols in green tea, showed lipase inhibition with an IC50 of 0.349 microM. Moreover, flavan-3-ol digallate esters, such as (-)-epigallocatechin-3,5-digallate, showed higher activities of inhibition on lipase with an IC50 of 0.098 microM. On the other hand, nonesterified flavan-3-ols, such as (+)-catechin, (-)-epicatechin, (+)-gallocatechin, and (-)-epigallocatechin, showed zero and/or the lowest activities against pancreatic lipase (IC50 > 20 microM). These data suggested that the presence of galloyl moieties within the structure was required for enhancement of pancreatic lipase inhibition. It is well-known that flavan-3-ols are polymerized by polyphenol oxidase and/or heating in a manufacturing process of oolong tea. Oolonghomobisflavans A and B and oolongtheanin 3'-O-gallate, which are typical in oolong tea leaves, showed strong inhibitory activities with IC50 values of 0.048, 0.108, and 0.068 microM, respectively, even higher than that of EGCG. The oolong tea polymerized polyphenols (OTPP) were prepared for the assay from oolong tea extract, from which the preparation effectively subtracted the zero and/or less-active monomeric flavan-3-ols by preparative high-performance liquid chromatography. The weight-average molecular weight (Mw) and number-average molecular-weight (Mn) values of OTPP were 2017 and 903, respectively, by using gel permeation choromatography. OTPP showed a 5-fold stronger inhibition against pancreatic lipase (IC50 = 0.28 microg/mL) by comparison with that of the tannase-treated OTPP (IC50 = 1.38 microg/mL). These data suggested that the presence of galloyl moieties within their chemical structures and/or the polymerization of flavan-3-ols were required for enhancement of pancreatic lipase inhibition.     

Online RP-HPLC-DPPH screening method for detection of radical-scavenging phytochemicals from flowers of Acacia confusa

Acacia confusa is traditionally used as a medicinal plant in Taiwan. In this study, phytochemicals and antioxidant activities of extracts from flowers of A. confusa were investigated for the first time. In addition, a rapid screening method, online RP-HPLC-DPPH system, for individual antioxidants in complex matrices was developed. Accordingly, six antioxidants including gallic acid ( 1), myricetin 3-rhamnoside ( 2), quercetin 3-rhamnoside ( 3), kaempferol 3-rhamnoside ( 4), europetin 3-rhamnoside ( 5), and rhamnetin 3-rhamnoside ( 6) were detected using the developed screening method. Of these, compounds 2, 3, and 5 were found to be major bioactive phytochemicals, and their contents were determined as 11.3, 6.7, and 8.7 mg/g of crude extract, respectively. By comparison with quercetin, a well-known antioxidant, these compounds had the order of compound 2 > compound 5 > quercetin > compound 3 for DPPH radical-scavenging activity. Their IC 50 values were 3.0, 3.2, 4.5, and 7.4 microM, respectively. Moreover, the same order was observed for superoxide radical-scavenging activity, and their IC50 values were 2.6, 2.7, 4.3, and 5.3 microM, respectively. However, for lipid peroxidation, quercetin, an aglycon, showed the best inhibitory activity. The IC50 values of quercetin, compound 2, compound 5, and compound 3 were 46.7, 88.5, 90.7, and 124.6 microM, respectively. These results indicated that a rhamnoside at the C3 position of flavonoids had a negative effect on radical-scavenging activity and antilipid peroxidation. In contrast, the number of hydroxyl groups on the B-ring exhibited a positive relationship with their inhibitory activities.     

Identification and antioxidant activity of novel chlorogenic acid derivatives from bamboo (Phyllostachys edulis)

One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.     

Essential oil and volatile emissions of basil (Ocimum basilicum) leaves exposed to NaCl or Na2SO4 salinity

The volatile compounds emitted by living leaves of basil (Ocimum basilicum L. cv. Genovese) plants under saline conditions were investigated by means of headspace–solid phase microextraction (HS‐SPME) and gas chromatography coupled with mass spectrometry (GC–MS). Furthermore, the composition of the essential oil obtained by hydrodistillation of the leaves was studied. Plants were grown for 15 d without salt or with an equimolar concentration of Na⁺ in the form of Na₂SO₄ (25 mM) and NaCl (50 mM), after which the growth, the essential oil, and the volatile constituents of the leaves were determined. Fifty‐four components were identified belonging to different chemical classes. Under control conditions, the essential oil was rich in linalool (45.9%), 1,8‐cineole (16.7%), eugenol (10.3%), trans‐α‐bergamotene, and epi‐α‐cadinol (4.9%). The main volatiles detected in the headspace of leaves of untreated basil plants were linalool (29.8%), followed by 1,8‐cineole (19.2%), trans‐α‐bergamotene (10.0%), and eugenol (7.0%). Under saline conditions, leaf growth was more depressed by 25 mM Na₂SO₄ than 50 mM NaCl, and essential oil concentration increased by 22% in the NaCl, but decreased by 18% in the Na₂SO₄ treatment, respectively. Both salts caused some changes in the essential oil and composition of volatile compounds. Most prominent was a strong negative correlation between eugenol and methyleugenol proportions, which may indicate an enhancement of the O‐methyltransferase activity. In comparison to the essential oil, the composition of volatiles showed some variations in their emission profile under both salts, the most important was an increase of eugenol. It is therefore concluded that the decrease of eugenol occurring in basil essential oil caused by both salts could be due to the enhancement of the eugenol O‐methyltransferase activity, an enzyme that accepts eugenol as substrate, generating methyl eugenol, and also to the increase of the eugenol emission as shown by the SPME profile.     

Chemical composition and antioxidant properties of clove leaf essential oil

The antioxidant activity of a commercial rectified clove leaf essential oil (Eugenia caryophyllus) and its main constituent eugenol was tested. This essential oil comprises in total 23 identified constituents, among them eugenol (76.8%), followed by beta-caryophyllene (17.4%), alpha-humulene (2.1%), and eugenyl acetate (1.2%) as the main components. The essential oil from clove demonstrated scavenging activity against the 2,2-diphenyl-1-picryl hydracyl (DPPH) radical at concentrations lower than the concentrations of eugenol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). This essential oil also showed a significant inhibitory effect against hydroxyl radicals and acted as an iron chelator. With respect to the lipid peroxidation, the inhibitory activity of clove oil determined using a linoleic acid emulsion system indicated a higher antioxidant activity than the standard BHT.     

Impact of alkyl esters of caffeic and ferulic acids on tumor cell proliferation, cyclooxygenase enzyme, and lipid peroxidation

The antioxidant ferulic and caffeic acid phenolics are ubiquitous in plants and abundant in fruits and vegetables. We have synthesized a series of ferulic and caffeic acid esters and tested for tumor cell proliferation, cyclooxygenase enzymes (COX-1 and -2) and lipid peroxidation inhibitory activities in vitro. In the tumor cell proliferation assay, some of these esters showed excellent growth inhibition of colon cancer cells. Among the phenolics esters assayed, compounds 10 (C12-caffeate), 11 (C16-caffeate), 21 (C8-ferulate), and 23 (C12-ferulate) showed strong growth inhibition with IC50 values of 16.55, 13.46, 18.67, and 7.57 microg/mL in a breast cancer cell line; 9.65, 7.45, 17.05, and 4.35 microg/ mL in a lung cancer cell line; 5.78, 3.5, 4.29, and 2.46 microg/mL in a colon cancer cell line; 12.04, 12.21, 14.63, and 8.09 microg/ mL in a central nervous system cancer cell line; and 8.62, 7.76, 11.0, and 5.37 in a gastric cancer cell line. In COX enzyme inhibitory assays, ferulic and caffeic acid esters significantly inhibited both COX-1 and COX-2 enzymes. Caffeates 5-10 (C4-C12), inhibited COX-1 enzyme between 50% and 90% and COX-2 enzyme by about 70%, whereas ferulates 15-21 (C3-C8) inhibited COX-1 and COX-2 enzymes by 85-95% 25 microg/mL. Long-chain caffeates 11-14 (C16-C22) and short-chain ferulates 15-20 (C3-C5) were the most active in lipid peroxidation inhibition and showed 60-70% activity at 5 microg/mL concentration.     

Novel antioxidant peptides from fermented mushroom Ganoderma lucidum

Oxidative stress has been linked with the pathogenesis of many human diseases including cancer, aging, and atherosclerosis. The present study investigates the antioxidant activities of peptides isolated from the medicinal mushroom, Ganoderma lucidum. G. lucidum has been shown to possess potent antioxidant activity with little or no side effects. Polysaccharide, polysaccharide-peptide complex, and phenolic components of G. lucidum have been proposed to be responsible for this antioxidant effect. However, research has shown that the G. lucidum peptide (GLP) is the major antioxidant component of G. lucidum. The objective of this study was to evaluate the antioxidant activity of this peptide using different oxidation systems. GLP showed potent antioxidant activities in both lightproof soybean oil and lard systems, assessed by lipid peroxidant value. Compared to butylated hydroxytoluene, GLP showed a higher antioxidant activity in the soybean oil system. Soybean lipoxygenase activity was blocked by GLP in a dose-dependent manner with an IC50 value of 27.1 microg/mL. GLP showed scavenging activity toward hydroxyl radicals produced in a deoxyribose system with an IC50 value of 25 microg/mL, and GLP effectively quenched superoxide radical anion produced by pyrogallol autoxidation in a dose-dependent manner. Malondialdehyde level has been used as the oxidation index in many biological systems. GLP showed substantial antioxidant activity in the rat liver tissue homogenates and mitochondrial membrane peroxidation systems. The auto-hemolysis of rat red blood cells was also blocked by GLP in a dose-dependent manner. On the basis of these results, it is concluded that GLP is the major constituent responsible for the antioxidant activity of G. lucidum. GLP could play an important role in the inhibition of lipid peroxidation in biological systems through its antioxidant, metal chelating, and free radical scavenging activities.     

Biologically active carbazole alkaloids from Murraya koenigii

The bioassay guided fractionation of the acetone extract of the fresh leaves of Murraya koenigii resulted in the isolation of three bioactive carbazole alkaloids, mahanimbine (1), murrayanol (2), and mahanine (3), as confirmed from their (1)H and (13)C NMR spectral data. Compound 2 showed an IC(50) of 109 microg/mL against hPGHS-1 and an IC(50) of 218 microg/mL against hPGHS-2 in antiinflammatory assays, while compound 1 displayed antioxidant activity at 33.1 microg/mL. All three compounds were mosquitocidal and antimicrobial and exhibited topoisomerase I and II inhibition activities.