Lipid Peroxidation Of Linoleic Acid Research Articles

A Sustainable Extraction Approach of Phytochemicals from Date (Phoenix dactylifera L.) Fruit Cultivars Using Ultrasound-Assisted Deep Eutectic Solvent: A Comprehensive Study on Bioactivity and Phenolic Variability.

The present study aimed to evaluate the efficacy of natural deep eutectic solvents (NADESs) on the extraction of phytochemicals from eight Algerian date fruit cultivars (Phoenix dactylifera L.). In this study, lactic acid/sucrose-based NADESs were used as an alternative to conventional chemical solvents using the ultrasound-assisted extraction (UAE) method. The obtained extracts were assessed for the determination of bioactive compound contents, phenolic composition, antioxidant activity, and enzyme inhibitory potential. The results showed a considerable variation in phytochemical compositions and related activities between cultivars, where the greatest contents of total phenolics (1288.7 mg GAE/100 g), total flavonoids (53.8 mg QE/100 g), proanthocyanidins (179.5 mg CE/g), and total triterpenoids (12.88 mg OAE/100 g) were detected in the fruits of the Ourous cultivar. The same cultivar displayed the highest antioxidant capacity against DPPH• free radical (595 mg AAE/100 g), ABTS•+ cation radical (839 mg TE/100 g), and ferric reducing antioxidant potential (704 mg AAE/100 g). All extracts manifested moderate antioxidant activities tested by phosphomolybdenum, NO•, and linoleic acid lipid peroxidation assays. These extracts also exhibited interesting levels of in vitro enzyme inhibition; the Ourous cultivar gave the best inhibitory activity against α-amylase and acetylcholinesterase with 45 and 37%, respectively. HPLC-DAD-MS detected a total of five compounds, with phenolic acids and flavonoids being the main phenolics identified in the extract. The phenolic composition exhibited significant variability among cultivars. Notably, the highest amounts were revealed in the Tazizaout cultivar, with the predominance of gallic acid. The results confirmed that the combination of UAE and NADESs provides a novel and important alternative to chemical solvents for sustainable and environmentally friendly extraction and can represent a good alternative in food and pharmaceutical industry applications.

Green Synthesis of Silver Nanoparticles from Allium cepa L. Peel Extract, Their Antioxidant, Antipathogenic, and Anticholinesterase Activity

The present work deals with the green synthesis and characterization of silver nanoparticles (AgNPs) using Allium cepa (yellowish peel) and the evaluation of its antimicrobial, antioxidant, and anticholinesterase activities. For the synthesis of AgNPs, peel aqueous extract (200 mL) was treated with a 40 mM AgNO3 solution (200 mL) at room temperature, and a color change was observed. In UV-Visible spectroscopy, an absorption peak formation at ~439 nm was the sign that AgNPs were present in the reaction solution. UV-vis, FE-SEM, TEM, EDX, AFM, XRD, TG/DT analyses, and Zetasizer techniques were used to characterize the biosynthesized nanoparticles. The crystal average size and zeta potential of AC-AgNPs with predominantly spherical shapes were measured as 19.47 ± 1.12 nm and -13.1 mV, respectively. Pathogenic microorganisms Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were used for the Minimum Inhibition Concentration (MIC) test. When compared to tested standard antibiotics, AC-AgNPs demonstrated good growth inhibitory activities on P. aeuruginosa, B. subtilis, and S. aureus strains. In vitro, the antioxidant properties of AC-AgNPs were measured using different spectrophotometric techniques. In the β-Carotene linoleic acid lipid peroxidation assay, AC-AgNPs showed the strongest antioxidant activity with an IC50 value of 116.9 µg/mL, followed by metal-chelating capacity and ABTS cation radical scavenging activity with IC50 values of 120.4 µg/mL and 128.5 µg/mL, respectively. The inhibitory effects of produced AgNPs on the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were determined using spectrophotometric techniques. This study provides an eco-friendly, inexpensive, and easy method for the synthesis of AgNPs that can be used for biomedical activities and also has other possible industrial applications.

Determination of Polyphenols Content and Antioxidant Activity of Citrus sinensis Fruit Peel

Citrus fruits have long been qualified as veritable foods in view of the many therapeutic benefits they bring to the body. Several researchers have stud-ied the relationship between the bioactive compounds of Citrus and the health benefits and reduction of the risk of disease. Citrus sinensis, used in the food industry and its extracts have also been used in traditional medicine to activate vital energy, circulation, and weight loss, and appetite control. However, limited efforts have been made on collecting data on antioxidant potential of peels orange from the northern region of Algeria. Our study, therefore, focuses on the evaluation of total polyphenols compounds and in vitro assessment of their antioxidant potential of peels orange from the northern region of Algeria. The ethyl acetate and n-butanolic fractions from peels orange have been tested for their antioxidant activities and their lipid peroxidation inhibiting effects. The total phenolic and flavonoids content showed high levels. The preliminary phytochemical screening of tannins, phenolic compounds, flavonoids, coumarin, and alkaloids was also used. DPPH assay possesses strong potency to scavenge free radicals. The NO. radi-cal scavenging test exerts a good inhibitory effect. Furthermore, orange peels have been shown to suppress the lipid peroxidation of linoleic acid. Results further revealed a strong correlation between antioxidant effects and polyphenolic compounds. The high antioxidant activity of peel orange suggests that it could serve as a good natural antioxidant additive or food dietary supplement.

Antioxidant peptides from Mytilus Coruscus on H2O2-induced human umbilical vein endothelial cell stress

The enzymatic protein hydrolysates of Mytilus coruscus (MCPH) were prepared with 5 proteases. The low molecular weight (MW) peptide fractions (<1 kDa, MCPH-T1) of trypsin hydrolysates were obtained using ultrafiltration. MCPH-T1 showed the most competitive DPPH•, ABTS+•, OH•, and O2−• scavenging activities compared to other enzymatic hydrolysates or high MW fractions. Compared to glutathione, MCPH-T1 showed better ferric ion-reducing power and inhibited lipid peroxidation of linoleic acid. In H2O2-induced oxidative injured of human umbilical vein endothelial cells (HUVEC), MCPH-T1 pre-treatment improved cell viability and ameliorated the morphological damage through attenuating the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) production and restored the cellular antioxidant capacities. In addition, MCPH-T1 showed a cytoprotective effect on dysfunctional cell by regulating the expressions of apoptotic and NF-κB proteins and restored the Nrf2-driven antioxidant defense mechanism. These results indicated that MCPH-T1 may be potential food ingredients for managing oxidative stress-related endothelial dysfunction or related cardiovascular diseases.

Antioxidant Profile of Home Prepared Taraxacum Officinale Weber Ex Wigg Beverage

Background: Aromatic plants are quite popular for daily use worldwide. However, little is known about the appropriate preparation of beverages in “house conditions” in order to preserve their beneficial characteristics after processing. Taraxacum officinale Weber ex Wigg contains a variety of compounds, with well-documented effects against oxidative stress. This study aims to investigate the optimum preparation conditions of a Taraxacum beverage in the household setting, with respect to its antioxidant characteristics. Methods: Dried, commercial T. officinale was used to prepare beverages boiling for 1, 3 or 5 min. The beverages were extracted using organic solvents of increasing polarity, and the solid residues of each extraction were examined by in vitro analysis on: the evaluation of total phenolic content (Folin Ciocalteau), the evaluation of antioxidant activity (DPPH and ABTS radicals scavenging), the evaluation of the ability of the tested extracts to compete with DMSO for OH radicals, the ability to inhibit lipid peroxidation of linoleic acid and soybean lipoxygenase inhibition assay. Results: All preparations had an overall good antioxidant profile. Regarding the chosen solvents, mid polarity solvents were more likely to give better results in all tests conducted, which can be indicative of the compounds extracted in each fraction. Samples prepared under 3 min boiling presented significant interaction with DPPH and strong lipoxygenase and lipid peroxidation inhibition. Conclusion: As previously observed in the literature, food processing can greatly affect its biochemical characteristics. In the case of Taraxacum, boiling for 3 min resulted in the best overall profile of the beverage with respect to its antioxidant properties. However, due to a variety of components present in each plant, further investigation and stratification, along with in vivo experiments are needed.

The Occurrence of Flavonoids and Related Compounds in Cedrus brevifolia A. Henry ex Elwes & A. Henry Needles. Inhibitory Potencies on Lipoxygenase, Linoleic Acid Lipid Peroxidation and Antioxidant Activity.

The phytochemical analysis of the polar extracts of Cedrus brevifolia needles yielded 20 compounds, namely from the methanol extract we isolated three flavonoids (1–3), one hydrolysable tannin (4), eleven phenolic derivatives (5–15) and one apocarotenoid (16), while from the methanol: water (5:1) extract we isolated four flavonoids (17–20). Chemical structures of all isolated compounds were determined by 1D, 2D-NMR (1 Dimension, 2 Dimensions Nuclear Magnetic Resonance) and UV-Vis (Ultraviolet-Visible) spectroscopy. Furthermore, the antioxidant potentials and the anti-inflammatory activities of both crude extracts and isolates were evaluated through DPPH radical scavenging capability, linoleic acid lipid peroxidation inhibition, and soybean LOX inhibition assays. This is the first report on the chemical profile of C. brevifolia needles. Catechin was the main compound derived from the methanol extract. According to our results, 4-O-β-d-glucopyranyl trans-p-coumaric acid and taxifolin were the most active ingredients.

Synthesis and antioxidant potential of some biscoumarin derivatives

Purpose: To synthesize and screen some 3-substituted-bis-2H-chromen-2t-ones in a search for possible new antioxidants for use in food and pharmaceuticals industries. Methods: 2-Hydroxycoumarin was allowed to react with various substituted aromatic aldehydes in the presence of base as a catalyst to obtain to obtain 3-substituted-bis-2H-chromen-2t-ones. The chemical structures of the synthesized compounds were confirmed by Fourier transform infra-red (FT-IR) spectroscopy, proton nuclear magnetic resonance ( 1 H NMR), mass spectrometry (MS) and elemental analysis. The synthesized biscoumarin derivatives were screened by three parallel antioxidant assays, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, reducing power, and linoleic acid lipid peroxidation. Further, the half minimal inhibitory concentration (IC 50 ) of the compounds was also determined. Butylatedhydroxy toluene (BHT) was used as a standard reference in the antioxidant assay. Results: A library of ten biscoumarin analogues ( 3a-3j ) were synthesized and evaluated for their antioxidant potential. The highest DPPH activity was shown by 3,3'-(3-hydroxy-4- methoxyphenylmethylene)-bis-4-hydroxy-2H-chromen-2-one ( 3g ) and 3,3'-(4-methoxyphenylmethylene)- bis-4-hydroxy-2H-chromen-2-one ( 3h ) with IC 50 values of 53.33 ± 6.12 and 68.44 ± 2.67 μg/mL, respectively, compared to the standard compound BHT (butylatedhydroxy toluene) with IC 50 of 71.00 ± 0.82 μg/mL. The strongest inhibition of linoleic acid peroxidation was by 3,3'-(3-hydroxy-4- methoxyphenylmethylene)-bis-4-hydroxy-2H-chromen-2-one ( 3g ) and 3'-(4-hydroxy-3-methoxyphenylmethylene)- bis-4-hydroxy-2H-chromen-2-one ( 3d ) with inhibition values of 70.34 and 69.87 %, respectively. Compound 3g demonstrated the highest reducing power with an absorbance of 0.49 at 10 mg/mL concentration (p < 0.001). It was observed that the change in substitution greatly affected the antioxidant potential of the compounds, with the presence of the methoxy group at position-4 of aryl moiety along with 2-hydroxycoumarin being critical for antioxidant activity. Conclusion: The synthesized biscoumarin derivatives, 3g and 3h , are superior antioxidants to standard (BHT) and are suitable lead molecules for further development. Keywords: Antioxidant, Biscoumarins, DPPH, Ferric reducing assay, linoleic acid lipid peroxidation assay

Study of the antioxidant activity of Thymus sibthorpii Bentham (Lamiaceae)

From the aerial parts of Thymus sibthorpii Bentham (Lamiaceae), five flavonoids apigenin (1), 7-methoxy-apigenin (2), naringenin (3), eriodictyol (4) and eriodictyol-7-glucoside (5), have been isolated together with caffeic acid methyl ester (6), rosmarinic acid (7) and rosmarinic acid methyl ester (8). The structures of the isolated compounds were established by spectroscopic methods. The extracts and the isolated compounds were tested for their free radical scavenging activity using the following in vitro assays: (i) interaction with the free stable radical of DPPH (1,1-diphenyl-2-picrylhydrazyl), (ii) inhibition of linoleic acid lipid peroxidation induced by the dihydrochloric acid of 2,2-azobis-2-amidinepropane (AAPH) and (iii) the scavenging activity of enzymatically produced superoxide anion. Their inhibitory activity toward soybean lipoxygenase was evaluated in vitro, using linoleic acid as a substrate. The antioxidant results of the extracts are discussed in terms of their constitution in phenolic compounds, which were determined following the Folin–Ciocalteu method.

The possible mode of antitussive and expectorant activity of the ethanol seed extracts of Picralima nitida ((Stapf) Th. & H. Durand)

It has been established that Picralima nitida has antitussive effect. This study therefore aimed at determining the possible mode of antitussive and expectorant activity of an ethanolic seed extract of P. nitida (PNE). The muco-suppressant, mast cell stabilization, and the anxiolytic effects of PNE were ascertained using ammonium chloride-induced phenol red secretion in BALB/c mice; compound 48/80-induced mesenteric mast cell degranulation assay; and the open field and the elevated plus maze models respectively. Antibacterial potential was ascertained by the agar plate diffusion method and its antioxidant potential by the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radical scavenging, linoleic acid lipid peroxidation, reducing power, and total antioxidant assays. Data obtained was analyzed using One-way analysis of variance (ANOVA) with Dunnett's Multiple Comparison post hoc test. PNE (100–500 mg/kg) reduced (P ≤ 0.05–0.001) tracheal phenol red secretion. The extract (100–500 μg/ml) also dose-dependently (P ≤ 0.05–0.0001) stabilized mast cells. PNE (100–500 mg/kg) increased open arm activities in the elevated plus maze (P ≤ 0.05) as well as central zone exploration (P ≤ 0.05) in the open field test. PNE (10–50 mg/ml) showed activity against Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, Klebsiella pneumonia, and Salmonella typhi. By the assays, PNE showed significant antioxidant effect. The ethanolic seed extract of P. nitida has demonstrated very significant mast cell stabilizing, mucus suppressant, and antioxidant activity as well as substantial antibacterial and anxiolytic properties; all of which could contribute to its antitussive and expectorant property.

Antioxidant activities of several Scutellaria taxa and bioactive phytoconstituents from Scutellaria hastifolia L.

This study was designed to evaluate the phenolic profiles and antioxidant potentials of different solvent extracts of four Scutellaria L. (Lamiaceae) taxa, S. hastifolia, S. velenovskyi, S. albida ssp. albida and S. orientalis ssp. pinnatifida, which are used in traditional medicines for various purposes. Among the investigated species, S. hastifolia was selected for further biological and phytochemical studies according to the results of preliminary screening assays. Phytochemical studies on S. hastifolia yielded a new phenylethanoid glycoside (hastifolioside) together with 16 known metabolites. The structures of the compounds were established on the basis of spectroscopic analyses. The antioxidant potentials and the antiinflammatory activities of the crude extracts of S. hastifolia as well as the isolates were evaluated through DPPH radical scavenging capability, linoleic acid lipid peroxidation inhibition and soybean LOX inhibition assays.

6-Methoxyflavonol Glycosides with In Vitro Hepatoprotective Activity from Chenopodium Bonus-henricus Roots

One new, namely 6-methoxykaempferol 3-O-[β-apiofuranosyl(l-->2)]-f-glucopyranosyl(l->6)-fl-glucopyranoside (2), and two known flavonoid glycosides, spinacetin 3-O-[β-apiofuranosyl(1-->2)]-β-glucopyranosyl(1-->6)-β-glucopyranoside (1) and spinacetin 3-O-gentiobioside (3), were isolated from the roots of Chenopodium bonus-henricus L. Their structures were determined by means of spectroscopic methods (ID, 2D NMR, UV, IR) and HR-ESI-MS. Radical scavenging and anti-oxidant activities of 1 and 3 were established using DPPH and ABTS free radicals, FRAP assay and inhibition of lipid peroxidation (LP) in a linoleic acid system by the ferric thiocyanate method. Compound 3 was found to possess stronger DPPH and ABTS radical scavenging activity (IC50 0.44 +/- 0.008 mM and 0.089 +/- 0.002 mM, respectively) compared with 1 (IC50 1.22 +/- 0.0 10 mM and 0.11 +/- 0.004 mM, respectively). Both flavonoids inhibited the lipid peroxidation of linoleic acid significantly. Additionally, 1 and 3 significantly reduced the cellular damage caused by the hepatotoxic agent CCI4 in rat hepatocytes and preserved cell viability and GSH level, decreased LDH leakage and reduced lipid damage. Effects were similar to those of the positive control silymarin. Control of self-toxic effects made in a MTT based assay using HepG2 cells revealed statistically significant cytotoxic effects only in very high concentrations (exceeding mM) and an incubation time of 72 h, making flavonoid glycosides with a 6-methoxykaempferol skeleton a promising and safe class of hepatoprotective compounds.

Antioxidant, antiradical, and anticholinergic properties of cynarin purified from the Illyrian thistle (Onopordum illyricum L.)

Cynarin is a derivative of hydroxycinnamic acid and it has biologically active functional groups constituent of some plants and food. We elucidated the antioxidant activity of cynarin by using different in vitro condition bioanalytical antioxidant assays like DMPD•+, ABTS•+, , DPPH• and H2O2 scavenging effects, the total antioxidant influence, reducing capabilities, Fe2+ chelating and anticholinergic activities. Cynarin demonstrated 87.72% inhibition of linoleic acid lipid peroxidation at 30 µg/mL concentration. Conversely, some standard antioxidants like trolox, α-tocopherol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) exhibited inhibitions of 90.32, 75.26, 97.61, 87.30%, and opponent peroxidation of linoleic acid emulsion at the identical concentration, seriatim. Also, cynarin exhibited effective DMPD•+, ABTS•+, , DPPH•, and H2O2 scavenging effects, reducing capabilities and Fe2+ chelating effects. On the contrary, IC50 and Ki parameters of cynarin for acetylcholinesterase enzyme inhibition were determined as 243.67 nM (r2: 0.9444) and 39.34 ± 13.88 nM, respectively. This study clearly showed that cynarin had marked antioxidant, anticholinergic, reducing ability, radical-scavenging, and metal-binding activities.

Organochalcogen compounds from glycerol: Synthesis of new antioxidants

We describe here a simple method for the synthesis of glycerol derivatives containing an organochalcogen unit (Se, Te and S) using NaBH4 and PEG-400 as a solvent. The new methodology was used to synthesize a range of new organochalcogen compounds in good yields. Furthermore, four of synthesized compounds were evaluated for their antioxidant activity using different assays, such as 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, nitric oxide (NO) and hydroxyl radical (OH) scavenging, ferric ion reducing antioxidant power (FRAP), ferrous ion chelating, superoxide dismutase-like activity and inhibition of linoleic acid lipid peroxidation. The new organotellurium 2,2-dimethyl-4-(phenyltellanylmethyl)-1,3-dioxolane 3j showed antioxidant activity and was more effective in inhibition of induced lipid peroxidation compared to solketal 4. Selenium and sulfur analogs 3a and 3m and solketal 4 did not present antioxidant effect. These findings suggest that 2,2-dimethyl-4-(phenyltellanylmethyl)-1,3-dioxolane 3j is a promising antioxidant and that its activity is influenced by the presence of the tellurium atom on the structure.

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

Ethnopharmacological importanceGastrointestinal disorders and infections are the major pathoaetiologies of diarrhoea causing many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat infectious diseases including diarrhoea and many other ailments by rural people in Africa and Asia. Much of the work done to date on this genus was on the non-polar or intermediate polarity components. Some parameters that may cause diarrhoea and the evaluation of more polar extracts have apparently not been investigated. AimsThe polar components were extracted and fractionated by solvent–solvent fractionation to yield fractions with different polarities. The activity of these fractions on different parameters that could be involved in factors associated with diarrhoea was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals. Materials and methodsPhenolic-enriched leaf extracts of Combretum bracteosum (COB), Combretum padoides (COP), Combretum vendae (COV) and Combretum woodii (COW) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. Acetone was removed from a portion of the 70% acetone extract and it was sequentially treated by solvent–solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures The antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2′-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid (ABTS+) radical scavenging, ferric reducing antioxidant power (FRAP) methods and lipid peroxidation inhibitory capacity standard methods. The ferric reducing antioxidant activities of the fractions were also determined. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out. ResultSome of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21–12µg/ml (COP), 0.25–16µg/ml (COV), 0.33–9.41µg/ml (COW) and 4.97–85µg/ml (COB) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28–1.51 and 1.02–1.19µg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 µg/ml. COP had the highest antibacterial activity with MICs ranging between 19–2500µg/ml, followed by COV with MICs ranging between 39–625µg/ml; COW and COB had similar MICs ranging between 39–2500µg/ml. COP also had the highest antifungal activity with MICs between 19–625µg/ml. The MIC for COW and COV ranged from 19 to 1250 µg/ml. COB had the lowest antifungal activity (MIC values were between 39 and 625 µg/ml). In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentration of hydrolysable tannin (gallotannin). A good correlation (R2= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity. ConclusionThe results obtained in this study with more polar extracts indicate that the use of extracts of these plant species as antidiarrhoeal agents may have a scientific basis. The extractant used here extracted a much higher percentage of the phytochemicals than acetone. It was better for isolating antioxidant compounds (polar) but not good for isolating antimicrobial compounds (non-polar) from the same species compared to acetone, ethyl acetate, dichloromethane, and hexane.

Minor iridoids from Scutellaria albida ssp. albida. Inhibitory potencies on lipoxygenase, linoleic acid lipid peroxidation and antioxidant activity of iridoids from Scutellaria sp.

A new iridoid glycoside, 6′-O-E-caffeoyl-mussaenosidic acid, in addition to one known aglycon, four known triterpenes and one known flavonoid, were isolated from the aerial parts of Scutellaria albida subsp. albida. Furthermore, 12 iridoids with similar structures isolated from Scutellaria sp., were examined for their inhibitory potency on lipoxygenase and lipid peroxidation, as well as their antioxidant activity, in comparison to known antioxidants e.g. caffeic acid, nordihydroguaretic acid (NDGA) and trolox. AAPH, DPPH and soybean lipoxygenase (LOX) assays were used for the tests. This investigation led to interesting observations considering the Structure-Activity Relationship. According to our results, the presence of a p-coumaroyl group optimized and even dramatically changed the biological responses of the investigated iridoids.

Antioxidant and Free Radical Scavenging Properties of an Aqueous ripe Fruit Extract of &lt;i&gt;Borassus aethiopum&lt;/i&gt; (M.) FWTA.

The palmyra palm, sometimes called the African fan palm, Borassus aethiopum, is an important food source in Ghana and other African countries. The present study was aimed at investigating the possible antioxidant properties of the aqueous fruit extract of this plant. The total phenolic content was assessed by the Folin-Ciocalteau assay, the antioxidant capacity assayed by the phosphomolydbenum method whereas the antioxidant activity was measured by the ability of the extract to scavenge DPPH (1, 1-diphenyl-2-picryl-hydrazyl) radicals. Also, the ability of the extract to inhibit lipid peroxidation was established using the linoleic acid autoxidation assay. The results indicate that the extract (0.1-10 mg/ml) contains phenolic compounds which may be responsible for the antioxidant properties since the coefficient of correlation between the total phenolic content and the total antioxidant capacity was high (r2 =0.9912). The n-propyl gallate (0.001-0.03 mg/ml), a reference antioxidant and the extract exhibited concentration-dependent free radical scavenging activity. The extract also inhibited concentration dependently the lipid peroxidation of linoleic acid. These findings suggest that the fruit extract of Borassus aethiopum contains antioxidant principles and its use as health supplement in alleviating oxidative stress can be exploited.Key words: Borassus aethiopum, Folin-Ciocalteau, phosphomolydbenum, 1, 1-diphenyl-2-picrylhydrazyl, n-propyl gallate.

Study of the participation of caffeine and polyphenols on the overall antioxidant activity of mate (Ilex paraguariensis)

The aim of this work was to investigate the participation of the main bioactive compounds (caffeine, caffeic acid derivatives and rutin) on the antioxidant activity (DPPH free radical scavenging activity and the prevention of lipid peroxidation) of the crude extracts of Ilex paraguariensis. Green and commercial products were used to prepare aqueous extracts. The main bioactive compounds were identified and quantified by HPLC-DAD. The antioxidant activities of the pure compounds in the concentrations present in the extracts were also analyzed. Results demonstrated that chlorogenic acid, caffeic acid and rutin contribute to the antioxidant activity. On the contrary, caffeine induced lipid peroxidation of linoleic acid acting as a pro-oxidant compound.The caffeine content in the green extracts was lower when compared to the commercial extracts. The antioxidant and pro-oxidant antagonistic effects of the compounds in the amounts present in the extracts resulted in higher antioxidant potency of the green extracts when compared to the commercial ones, as demonstrated by the EC50 values and without affecting the maximum efficiency displayed by the extracts.

Thrombin inhibitors with lipid peroxidation and lipoxygenase inhibitory activities

Vascular oxidative stress, endothelial injury, and thrombosis are intertwined processes that display a synergistic pathological effect in many cardiovascular diseases. Antithrombotic therapy with anticoagulant and/or antiplatelet agents, combined with interventions against vascular oxidative stress and/or inflammation, both boosting endothelial antithrombotic potential, could display a synergistic action in the treatment of thrombosis. Of the compounds 10a-h and 11a-d, shown to possess thrombin inhibitory activity, 11a-d were found to display radical scavenging activity, 10a, 10d, and 10f were demonstrated to inhibit lipid peroxidation of linoleic acid, and 10b and 10h inhibited soybean lipoxygenase. The observed combination of thrombin inhibition with lipid peroxidation and/or lipoxygenase inhibitory activity makes compounds 10 and 11 interesting candidates for further investigations towards multiple antithrombotic drugs.

Comparative Study on Antioxidant Activity of Lycopene (Z)-Isomers in Different Assays

Several studies have implicated the potent antioxidant properties of lycopene. However, most of the studies used only the (all-E)-isomer. (Z)-Isomers of lycopene were found in substantial amounts in processed foods and in human tissues. In the present study, we investigated in vitro the antioxidant activity of (5Z)-, (9Z)-, and (13Z)-lycopene compared to the (all-E)-isomer. Additionally, prolycopene, the (7Z,9Z,7'Z,9'Z)-isomer found in tangerine tomatoes, was analyzed. No significant differences were found between the isomers in ferric reducing antioxidant power assay and in bleaching the radical cation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), both based on ET mechanisms. In contrast, scavenging activity against peroxyl radicals generated by thermal degradation of 2,2'-azobis(2-amidinopropane) (AAPH) was higher in the (Z)-isomers. (5Z)-Lycopene was most antioxidant in scavenging lipid peroxyl radicals, evaluated by analyzing the inhibition of MbFe(III) lipid peroxidation of linoleic acid in mildly acidic conditions (pH 5.8) in a micellar environment, modeling a possible antioxidant action in the gastric compartment.

Propolis as potential cosmeceutical sunscreen agent for its combined photoprotective and antioxidant properties

Propolis, bee glue, and its main polyphenolic components show high antioxidant activity as found measuring their inhibitory action on lipid peroxidation of linoleic acid (LA) in sodium dodecyl sulfate (SDS) micelles. Furthermore, these substances evidence effectiveness as broad spectrum UVB and UVA photoprotection sunscreens, as it results by measurements of sun protection factor (SPF), the universal indicator related primarily to UVB radiations, and of the two parameters giving an indication of the UVA absorbance properties, i.e. UVA/UVB ratio and critical wavelength. The combination of these characteristics moves up propolis and its main polyphenolic components to the class of cosmeceuticals, as possible active ingredient of sunscreen commercial formulations for their protective and preventive properties.