Free radical scavengers from Mutisia friesiana (Asteraceae) and Sanicula graveolens (Apiaceae)

Scutellarein Suppresses the Production of ROS and Inflammatory Mediators of LPS-Activated Bronchial Epithelial Cells and Attenuates Acute Lung Injury in Mice

Scutellarein is a key active constituent present in many plants, especially in Scutellaria baicalensis Georgi and Erigeron breviscapus (vant.) Hand-Mazz which possesses both anti-inflammatory and anti-oxidative activities. It also is the metabolite of scutellarin, with the ability to relieve LPS-induced acute lung injury (ALI), strongly suggesting that scutellarein could suppress respiratory inflammation. The present study aimed to investigate the effects of scutellarein on lung inflammation by using LPS-activated BEAS-2B cells (a human bronchial epithelial cell line) and LPS-induced ALI mice. The results showed that scutellarein could reduce intracellular reactive oxygen species (ROS) accumulation through inhibiting the activation of NADPH oxidases, markedly downregulating the transcription and translation of pro-inflammatory cytokines, including interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), and C-X-C motif chemokine ligand (CXCL) 8 in LPS-activated BEAS-2B cells. The mechanism study revealed that it suppressed the phosphorylation and degradation of IκBα, consequently hindering the translocation of p65 from the cytoplasm to the nucleus and its subsequent binding to DNA, thereby decreasing NF-κB-regulated gene transcription. Notably, scutellarein had no impact on the activation of AP-1 signaling. In LPS-induced ALI mice, scutellarein significantly decreased IL-6, CCL2, and tumor necrosis factor-α (TNF-α) levels in the bronchoalveolar lavage fluid, attenuated lung injury, and inhibited neutrophil infiltration. Our findings suggest that scutellarein may be a beneficial agent for the treatment of infectious pneumonia by virtue of its anti-oxidative and anti-inflammatory activities.

Phenolic Profile and Cholinesterase Inhibitory Properties of Three Chilean Altiplano Plants: Clinopodium gilliesii (Benth.) Kuntze [Lamiaceae], Mutisia acuminata Ruiz & Pav. var. hirsuta (Meyen) Cabrera, and Tagetes multiflora (Kunth) [Asteraceae]

This research aimed to identify the phenolic profile and composition of the aerial parts of three native species used in traditional medicine in the Andean Altiplano of northern Chile: Clinopodium gilliesii (Benth.) Kuntze [Lamiaceae] (commonly known as Muña-Muña), Mutisia acuminata Ruiz & Pav. var. hirsuta (Meyen) Cabrera [Asteraceae] (commonly known as Chinchircoma), and Tagetes multiflora (Kunth), [Asteraceae] (commonly known as Gracilis), as well as to evaluate their potential inhibitory effects against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Polyphenolic enriched-extracts (PEEs) of the species were prepared and analyzed and the main components were quantified using HPLC-DAD. In total, 30 phenolic compounds were identified and quantified in all species, including simple phenolics, hydroxycinnamic acids, flavan-3-ols (monomers and polymers), flavanones, and flavonols. In addition, other main phenolics from the extracts were tentatively identified by ESI-MS-MS high-resolution analysis. T. multiflora extract showed the greatest anti-AChE and BChE activity in comparison with C. gilliesii and M. acuminata extracts, being the anti-AChE and BChE activity weak in all extracts in comparison to galantamine control. To comprise to better understand the interactions between cholinesterase enzymes and the main phenolics identified in T. multiflora, molecular docking analysis was conducted.

Chemical characterization and biological activities of ulvan extracted from Ulva fasciata (Chlorophyta)

Ulvan is a sulfated heteropolysaccharide present in the cell wall of Ulva species with a unique structure and biological potential used in various fields. Chemical characterization was carried out to determine the structure of ulvan from Ulva fasciata Delile collected from Eastern Harbor, Alexandria coast, Egypt. Ulva contains 31.5% carbohydrate with a total ulvan content of 43.66% of total carbohydrate (13.75 g/100 g DW) and sulfate content of 20.45% of ulvan. FTIR spectrum presented signals of the sulfate ester (C–O–S) and sulfate groups (S=O), typical for ulvan. GC–MS revealed that ulvan was mainly composed of rhamnose and fucose. 1H-NMR spectra of ulvan showed identical behavior of monosaccharides nature with peaks characteristic of sulfated polysaccharides at 3.2–5.3 ppm region. Scanning electron micrographs (SEM) demonstrated amorphous architecture, and the sulfated nature of polysaccharides was emphasized by EDX analysis. The extracted ulvan showed significant antimicrobial activity against human and fish pathogens as well as antifouling bacteria with minimum inhibitory concentrations (MIC) of 8 µg/mL. The extracted ulvan exhibited potent antioxidant activity with a scavenging effect of 84.93% for 2,2-diphenyl-1-picrylhydrazy free radical (DPPH). Moreover, it showed anti-arthritic properties for the first time with a maximum inhibition of 86.04% with IC50 of 43.21%, indicating their potential value for the health and food industry.

Chemical and biological investigations of Limonium axillare reveal mechanistic evidence for its antidiabetic activity

Root and bark of Limonium axillare (Forssk) Kuntze are used as antidiabetic remedies in parts of East Africa, but this activity has never been fully investigated. To validate its ethnobotanical use, we compared the chemical and pharmacological profiles of the ethanolic extracts of L. axillare root (REE) and aerial parts (AEE). Administration of REE (500 mg kg-1) reduced streptozotocin-induced hyperglycemia by 44%, restored serum insulin levels, reestablished Glut2 and Glut4 expression and ameliorated pancreatic tissue damage in diabetic rats. In vitro studies revealed a strong radical scavenging effect, α-glucosidase, and α-amylase inhibition activity of REE at IC50 at 25.2, 44.8 and 89.1μg/mL, respectively. HPLC analysis identified ten phenolic compounds in REE with umbelliferone as the major constituents at 10 ± 0.081 mg/g of extract. Additionally, six compounds were isolated from REE including, β-sitosterol-3-palmitate, β-sitosterol, myricetin and gallic acids with two new tetrahydrofuran monoterpenes; 2-isopropyl- 3,4,4, trimethyl-tetrahydrofuran (3), and 2-isopropyl-4-methyl-tetrahydrofuran-3,4 dicarboxylic acid (4), the latter was revealed by molecular docking to be a good ligand to glycerol-3-phosphate dehydrogenase a key enzyme in glycolysis.

The Potential of a New Commercial Seaweed Extract in Stimulating Morpho-Agronomic and Bioactive Properties of Eruca vesicaria (L.) Cav

This study aimed to understand the effect of commercial seaweed extract as a biofertilizer, named True-Algae-Max (TAM®), on the yield, nutritional, antioxidant, and cytotoxic activity of Eruca vesicaria. Three concentrations of TAM® (5, 10, and 15%) were studied by foliar spray over the two cultivation years (2016 and 2017) without any chemical fertilizer, along with a control consisting of synthetic nitrogen, phosphorus and potassium (NPK) fertilizers. The yield and composition of E. vesicaria were significantly improved in all treatments, particularly at 10% concentration of TAM®, which resulted in maximum yield (1.99 kg m−2) and significant amounts of chlorophyll, carotenoids, phenolic compounds, flavonoids and total nutrients. Compared to the NPK control, E. vesicaria grown with 10% of TAM® improved total antioxidant activity from 41.80 to 49.36 mg g−1 and cytotoxicity from 25.30 to 60.40% with an IC50 value 85.7 µg mL−1 against the hepatocellular carcinoma cell line (HepG2). These findings indicate that seaweed extract can generally be used as a safe potential multifunctional biofertilizer in the agricultural field. The use of seaweed as a biofertilizer could potentially help mitigate the adverse effects of main nutrient deficiencies, diminishing the use of chemical fertilizers.

Antioxidant, Cytotoxicity, and Antiophidian Potential of Alstonia macrophylla Bark

The objective of this research was to find the possible pharmacognosy of the bark of the Philippine Alstonia macrophylla Wall. ex G.Don (AM). Gas chromatographic-mass spectral (GC-EI-MS) characterization and energy dispersive X-ray spectroscopy (EDX) were performed to detect the bioactive constituents. EDX analysis of AM bark displayed a high content of potassium (3.26%) and calcium (2.96%). Eight constituents were detected in AM crude dichloromethane (DCM) extracts, which consisted of a long-chain unsaturated fatty acid (17:0) and fatty acid esters such as ethyl hexadecanoate and methyl hexadecanoate. Extraction of AM bark using methanol and dimethyl sulfoxide (MeOH/DMSO) solvents resulted in the identification of 17 constituents, principally alkaloids (alstonerine, 34.38%; strictamin, 5.23%; rauvomitin, 4.29%; and brucine, 3.66%) and triterpenoids (γ-sitosterol, 3.85%; lupeol, 3.00%; 24-methylenecycloartanol, 2.81%; campesterol, 2.71%; β-amyrin, 2.30%; and stigmasterol, 2.13%). MeOH/DMSO samples of AM were used in the selected bioassays. The samples exhibited efficient free radical scavenging activity (IC₅₀ = 0.71 mg/mL) and were noncytotoxic to normal HDFn (IC₅₀ > 100 μg/mL) and neoplastic THP-1 cell lines (IC₅₀ = 67.22 μg/mL) while highly degenerative to MCF-7 (IC₅₀ = 6.34 μg/mL), H69PR (IC₅₀ = 7.05 μg/mL), and HT-29 (IC₅₀ = 9.10 μg/mL). Most interestingly, the AM samples inhibited the northern Philippine Cobra's (Naja philippinensis Taylor) venom (IC₅₀ = 297.27 ± 9.33 μg/mL) through a secretory phospholipase A₂ assay.

Antimicrobial, antioxidant properties and chemical composition of seaweeds collected from Saudi Arabia (Red Sea and Arabian Gulf)

The present study demonstrates the antibacterial activity of selected brown and green marine algae collected from Saudi Arabia Red Sea and Arabian Gulf. The methanolic and acetone extracts were tested against gram positive, gram negative bacteria and Candida albicans in an attempt to be used as an alternative to commonly used antibiotics. Both brown seaweed species Sargassum latifolium B and Sargassum platycarpum A methanolic extracts were found to be active against gram positive than gram negative; however, S. latifolium acetone extract gave the highest inhibitory activity against Salmonella sp. On the other hand, Cladophorasocialis organic extract demonstrated higher antibacterial activity than the fresh extract but both C. socialis extracts revealed decreased activity compared to Sargassum extracts. Cladophora methanolic extract showed an obvious effect on methicillin resistant Staphylococcus aureus (MRSA). The present work shows a comparable therapeutic potency of the tested seaweed members Sargassum and Cladophora extracts in treating human microbial pathogens to synthetic chemical antibiotics. A remarkable higher antioxidant DPPH free radical scavenging effect was recorded with Sargassum sp. compared to Cladophora sp. FTIR Infrared Spectrometer analysis together with the high performance liquid chromatography provided a detailed description of the possible functional constituents and the major chemical components present in marine macroalgae particularly in brown seaweeds to be mainly of phenolic nature to which the potent antimicrobial activity is being attributed.

Antioxidant activity and mineral composition of three Mediterranean common seaweeds from Abu-Qir Bay, Egypt

Antioxidant activity and mineral composition were evaluated seasonally from spring to autumn 2010 in the three common seaweeds Ulva lactuca Linnaeus (Chlorophyta), Jania rubens (Linnaeus) J.V. Lamouroux and Pterocladia capillacea (S.G. Gmelin) Bornet (Rhodophyta). The antioxidant activity was measured with β-carotene, total phenol content and DPPH (2,2-diphenyl-1-picrylhydrazyl). Seaweeds were collected from the rocky site near Boughaz El-Maadya Abu-Qir Bay of Alexandria, Egypt. The results showed maximum increase of β-carotene in P. capillacea during summer. A significant increase in total phenolic content at P ⩽ 0.05 was found in the red alga (J. rubens) during summer. Also, U. lactuca showed the maximum antioxidant scavenging activity especially during summer. Minerals in all investigated samples were higher than those in conventional edible vegetables. Na/K ratio ranged between 0.78 and 2.4 mg/100 g, which is a favorable value. All trace metals exceeded the recommended doses by Reference Nutrient Intake (RNI). During summer season, it was found that Cu = 2.02 ± 0.13 and Cr = 0.46 ± 0.14 mg/100 g in U. lactuca and Fe had a suitable concentration (18.37 ± 0.5 mg/100 g) in P. capillacea. The studied species were rich in carotenoids, phenolic compounds, DPPH free radicals and minerals, therefore, they can be used as potential source of health food in human diets and may be of use to food industry.

Extract from Ceratonia siliqua Exhibits Depigmentation Properties

Skin hyper-pigmentation is a condition initiated by the overproduction of melanin existing in the melanocytes. Melanin pigment is responsible for the colour of skin in humans. It is formed through a series of oxidative reactions involving the amino acid tyrosine in the presence of the key enzyme tyrosinase. In continuation with our efforts to identify tyrosinase inhibitors from plants sources, the methanol extract from leaf, bark and fruit of Ceratonia siliqua were screened for tyrosinase inhibition and diphenolase activity. The bark extract exhibited significant inhibition on mushroom tyrosinase using L-tyrosine as a substrate and showed diphenolase activity. The extract further significantly lowered tyrosinase mRNA levels in B16-F10 mouse melanocytes. Bioassay-guided fractionation led to the isolation of six compounds. Compounds (-)-epicatechin-3-O-gallate, 1,2,3,6-tetra-O-galloyl-ß-D-glucose and gallocatechin-3-O-gallate showed tyrosinase inhibitions with the IC50 values of 27.52, 83.30 and 28.30 µg/mL, respectively. These compounds also exhibited L-DOPA activities with IC50 values of >200, 150 and 200 µg/mL, respectively. A clinical study was conducted using 20 volunteers in a patch testing trial for irritancy potential and skin depigmentation. The clinical results showed the sample to be non-irritant with irritancy potential of -34.21 and depigmentation trial showed an improvement in the even skin tone of UV induced pigmentation at 3% after 28 days of application.

Neurochemical, structural and neurobehavioral evidence of neuronal protection by whey proteins in diabetic albino mice

Background

Diabetes Mellitus (DM) is associated with pathological changes in the central nervous system (CNS) and alterations in oxidative stress. The aim of this study was to determine whether dietary supplement with whey protein (WP) could improve neurobehavior, oxidative stress and neuronal structure in the CNS.

Methods

Animals were distributed in three groups, a control group (N), a diabetic mellitus group (DM) and a DM group orally supplemented with WP (WP).

Results

The DM group of animals receiving WP had reduced blood glucose, significantly decreased free radical Diphenyl-picrylhydrazyl (DPPH) and lower lipid peroxidation in brain tissue. The WP group of animals showed improvement in balancing, coordination and fore-limb strength, oxidative stress and neuronal structure.

Conclusion

The results of this study show that dietary supplementation with WP reduced oxidative stress, protected CNS neurons and improved the neurobehavior of diabetic mice.

Antioxidant, anti-diabetic and renal protective properties of Stevia rebaudiana

BACKGROUND

Stevia rebaudiana Bertoni has been used for the treatment of diabetes in, for example, Brazil, although a positive effect on antidiabetic and its complications has not been unequivocally demonstrated. This herb also has numerous therapeutic properties which have been proven safe and effective over hundreds of years. Streptozotocin is a potential source of oxidative stress that induces genotoxicity.

OBJECTIVE

We studied the effects of stevia leaves and its extracted polyphenols and fiber on streptozotocin induced diabetic rats. We hypothesize that supplementation of polyphenols extract from stevia to the diet causes a reduction in diabetes and its complications.

DESIGN/METHODS

Eighty Wistar rats were randomly divided into 8 groups; a standard control diet was supplemented with either stevia whole leaves powder (4.0%) or polyphenols or fiber extracted from stevia separately and fed for one month. Streptozotocin (60 mg/kg body weight, i.p) was injected to the diabetic groups on the 31st day. Several indices were analyzed to assess the modulation of the streptozotocin induced oxidative stress, toxicity and blood glucose levels by stevia.

RESULTS

The results showed a reduction of blood glucose, ALT and AST, and increment of insulin level in the stevia whole leaves powder and extracted polyphenols fed rats compared to control diabetic group. Its feeding also reduced the MDA concentration in liver and improved its antioxidant status through antioxidant enzymes. Glucose tolerance and insulin sensitivity were improved by their feeding. Streptozotocin was also found to induce kidney damage as evidenced by decreased glomerular filtration rate; this change was however alleviated in the stevia leaves and extracted polyphenol fed groups.

CONCLUSION

The results suggested that stevia leaves do have a significant role in alleviating liver and kidney damage in the STZ-diabetic rats besides its hypoglycemic effect. It might be adequate to conclude that stevia leaves could protect rats against streptozotocin induced diabetes, reduce the risk of oxidative stress and ameliorate liver and kidney damage.

Antioxidant potential and total phenolic content of methanolic bark extract of Madhuca indica (koenig) Gmelin

This study was carried out to investigate the antioxidant and free radical scavenging activity of methanolic extract of Madhuca indica bark in varios systems. DPPH radical, superoxide anion radical, nitric oxide radical, hydroxyl radical, lipid peroxidation, and total phenolic content assays were carried out to evaluate the antioxidant potential of the extract. The percentage inhibition of 40 μg/ml concentration of MMI in DPPH radical scavenging model was found as 74.1%. The scavenging of nitric oxide by the plant extract was concentration dependent and IC₅₀ value of rutin was found to be 161.7 μg/ml. MMI elicited significant and concentration-dependent superoxide radical scavenging effect with MMI as well as standard curcumin, which exhibited IC₅₀ values of 38.1 and 5.84 μg/ml, respectively. MMI demonstrated significant scavenging activity of OH^- radical generated from Fe²⁺-ascorbate-EDTA-H₂O₂ in a concentration-dependent manner. The extract showed a significant dose-dependent free radical scavenging activity in all the models. The extract showed the presence of high phenolic content corresponding to 98.48 μg equivalent of gallic acid and the antioxidant activity could be attributed to this.

Studies on antioxidant activities of breviscapine in the cell-free system

Breviscapine is a commercially produced plant extract from the Chinese herb Erigeron breviscapus. (Vant.) Hand.-Mazz., which contains 2 main flavonoids. It is widely used in clinic to treat ischemic diseases in which free radicals are considered to be the main causal factor. Our study is aimed to examine the antioxidant activity of this extract. The following assays were employed: 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging, nitric oxide radical scavenging, total anti-oxidative capacity, and antilipid peroxidation assays. Breviscapine was demonstrated to show an effective activity on scavenging DPPH, superoxide anion radicals and nitric oxide. The total antioxidative capacity of breviscapine (7.8 microg/ml to 250 microg/ml) was 1.22 to 6.74 FRAP value (x 10(-5) mmol). At the highest concentration of breviscapine, the inhibition extent of lipid peroxidation induced by Fe(2+) in rat liver homogenates was 38.5%. Because of the antioxidant activity, the present study is therefore designed to investigate the therapeutic potential of breviscapine for treatment of ischemic diseases.

Antioxidant and Membrane Stabilizing Properties of the Flowering Tops of Anthocephalus Cadamba

The hydroethanolic extract of Anthocephalus cadamba displayed remarkable antioxidative potential in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), the hydrogen peroxide, the nitric oxide scavenging, the reducing power, the total antioxidant capacity, the lipid peroxidation inhibition (thiobarbituric acid-reactive substances production), and the RBC membrane stabilization assays. While in the DPPH assay the IC50 value of the extract was 146.5 μg/mL, it was 24.8 μg/mL in the nitric oxide scavenging assay.

DPPH and oxygen free radicals as pro-oxidant of biomolecules

Numerous investigations exist about the alterations that oxygen free radicals can provoke on biomolecules; these modifications can be prevented and/or reversed by different antioxidants agents. On the other hand, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), a stable nitrogen synthetic radical, is used to evaluate the antioxidant capacity of medicinal herbal products; however, the structural changes that this radical provoke on the herbal active principles are not clear yet. In this work, we compared the redox reactivity of oxygen free radicals and DPPH radical on phospholipids and protein thiol groups present in rat liver microsomes. Cu2+/ascorbate was used as generator system of oxygen free radical and as antioxidant, an extract of Buddleja globosa's leaves. Cu2+/ascorbate provoked microsomal lipid peroxidation, microsomal thiols oxidation and oxygen consumption; all of these phenomena were inhibited by B. globosa extract. On the other hand, DPPH was bleached in different extension by the herbal extract and phosphatidyl choline; beside, DPPH decreased microsomal thiols content, but this phenomenon were not prevented by the herbal extract. Furthermore, DPPH did not induce oxygen consumption and neither modified the oxygen consumption induced by Cu2+/ascorbate. Distinct redox mechanisms may explain the differences between the reactivity of DPPH and oxygen free radicals on biomolecules, which is discussed.

Cytisus scoparius link--a natural antioxidant

BACKGROUND

Recent investigations have shown that the antioxidant properties of plants could be correlated with oxidative stress defense and different human diseases. In this respect flavonoids and other polyphenolic compounds have gained the greatest attention. The plant Cytisus scoparius contains the main constituent of flavone and flavonals. The present study was undertaken to evaluate the in vitro antioxidant activities of extract of aerial part of Cytisus scoparius.

METHODS

The plant extract was tested for DPPH (1, 1-diphenyl, 2-picryl hydrazyl) radical scavenging, nitric oxide radical scavenging, superoxide anion radical scavenging, hydroxyl radical scavenging, antilipid peroxidation assay, reducing power and total phenol content.

RESULTS

The extract exhibited scavenging potential with IC50 value of 1.5 microg/ml, 116.0 microg/ml and 4.7 microg/ml for DPPH, nitric oxide and superoxide anion radicals. The values were found to lesser than those of vitamin C, rutin, and curcumin, as standards. The extract showed 50% protection at the dose of 104.0 microg/ml in lipid peroxidation induced by Fe2+/ ascorbate system in rat liver microsomal preparation. There is decrease in hydroxyl radical generation with IC50 value of 27.0 microg/ml when compared with standard vitamin E. The reducing power of the extract depends on the amount of extract. A significant amount of polyphenols could be detected by the equivalent to 0.0589 microg of pyrocatechol from 1 mg of extract.

CONCLUSION

The results obtained in the present study indicate that hydro alcoholic extract of aerial part of Cytisus scoparius is a potential source of natural antioxidants.

Distribution of a new rosmarinic acid derivative in Eryngium alpinum L. and other Apiaceae

The roots of Eryngium alpinum L. (Apiaceae) demonstrated radical scavenging properties toward the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in a TLC autographic assay. Isolation of the bioactive compounds allowed the identification of R-(+)-3'-O-beta-D-glucopyranosyl rosmarinic acid, a new rosmarinic acid derivative. The quantitative determination of the antioxidant capacity of the compound by chemoluminescence demonstrated half the activity of R-(+)-rosmarinic acid. To find another source richer in this compound, a chemotaxonomic study was conducted. The higher content was found in the aerial parts of Sanicula europeae L., also belonging to the Saniculoideae subfamily. Although present in most of the Eryngium species, this compound was not detected in Imperatoria ostruthium L., Pimpinella peregrina L., and Levisticum officinalis L. species from the Apioideae subfamily and Hydrocotyle asiatica L. from the Hydrocotyloideae subfamily. The results indicate that the new derivative R-(+)-3'-O-beta-D-glucopyranosyl rosmarinic acid is a potential chemotaxonomic marker of the Saniculoideae subfamily.

Hepatoprotective and antioxidant effects ofAlnus japonica extracts on acetaminophen-induced hepatotoxicity in rats

The stem bark of the Betulaceae plant Alnus japonica, which is indigenous to Korea, has been used as a popular folk medicine for hepatitis and cancer. In this study, the antioxidant activity of the crude extract and the hepatoprotective activities on acetaminophen (AAP)-induced toxicity in the rat liver were evaluated. We investigated the effect of the methanol (AJM) and solvent fracton of the stem bark of Alnus japonica (AJ) on AAP-induced hepatotoxicity in rats. In rat hepatocyte culture, pretreatment with AJM (50, 100, 150 and 200 microg/ml) significantly decreased the cytotoxicity of AAP in a dose-dependent manner. The pretreated with EtOAc and BuOH fraction led to an increase in free radical scavenging activity and a decrease in inhibition of lipid peroxidation, both superoxide dismutase and catalase prevent the hepatotoxicity by AAP in the treatment of A. japonica fraction. We conclude that AJ is an important antioxidant in AAP-induced live hepatotoxicity and that extract of AJM plays a hepatoprotective effects in the against AAP-induced cytotoxicity in cultured rat hepatocytes in vitro. Pending more evaluation for safety and efficacy, AJ can potentially be used in mitigating AAP-induced hepatotoxicity.

5-methylcoumaranones from Mutisia friesiana and their bioactivity

In addition to the known mutisicoumaranones A (1) and B (2), the methanolic extract of the aerial parts of the shrub Mutisia friesiana afforded two new 5-methylcoumaranones, mutisicoumaranones C (3) and D (4). Their structures were elucidated by spectroscopic methods. (13)C NMR data for mutisicoumaranones A and B are reported for the first time. All compounds showed antifungal activity against the phytopathogenic fungus Cladosporium cucumerinum and bactericidal activity against Staphylococcus aureus. The presence of 5-methylcoumaranones A-D is biosynthetically related to 5-methylcoumarins and phenolic derivatives previously isolated from M. friesiana.

Antioxidant properties of Indian medicinal plants

The antioxidant properties of methanol extracts of 12 Indian medicinal plants, traditionally used in disease areas that probably involve free radical mechanisms, were evaluated by two methods, namely the DPPH (1,1-diphenyl-2-picryl hydrazyl) test and the lipid peroxidation assay. In the latter assay, seven of these extracts showed 90% or more activity compared with the standard, vitamin E and hence were studied in detail after the removal of interfering pigments. The selective pigment removal from the extracts led to an increase in free radical scavenging activity and a decrease in inhibition of lipid peroxidation.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

Antioxidative and radical scavenging effects of olive cake extract

The antioxidative activity of different butanol extract fractions of olive cake was investigated. Four fractions showed marked antioxidative activity in comparison with BHT. Fractions tested also showed good hydrogen donating abilities, indicating that they had effective activities as radical scavengers. Coumaric, ferulic, cinnamic acids and oleuropein were isolated.

Free radical scavengers, anti-inflammatory and analgesic activity of Acaena magellanica

Extracts of the whole plant Acaena magellanica (Rosaceae) were assessed for anti-inflammatory, antipyretic and analgesic activity in animal models. At 600 mg kg(-1), the global ethanolic extract (GEE), dichloromethane (DCM) and defatted methanol (MeOH) fractions showed a mild anti-inflammatory effect in the carrageenan-induced guinea-pig paw oedema. The GEE, DCM and defatted MeOH fractions significantly reduced inflammation by 43.2, 40.5 and 42.1%, respectively. The GEE did not showed any significant antipyretic activity in doses up to 600 mg kg(-1). A 20% w/v infusion administered orally at 16 mL kg(-1) presented analgesic effect in the acetic acid-induced abdominal constriction test in mice. The GEE and MeOH extract of A. magellanica showed free radical scavenging activity in the diphenylpicrylhydrazyl decolouration assay. Assay-guided isolation led to quercetin, Q-3-O-beta-glucoside, Q-3-O-beta-D-galactoside, ellagic acid and catechin as the free radical scavengers. The saponins tormentic acid 28-O-beta-D-galactopyranoside and 28-O-beta-D-glucopyranoside were isolated from the polar extract. The structures were determined by spectroscopic methods.

Free radical scavenging activity of Lafoensia pacari

The methanolic extract of the stem bark of Lafoensia pacari (Lythraceae) showed free radical scavenging activity in the diphenyl picryl hydrazyl radical (DPPH) decoloration assay and inhibited the enzyme xanthine oxidase 'in vitro'. Bioassay-guided isolation led to ellagic acid (EA) as the main active compound of Brazilian and Paraguayan collections of the plant.

Biologically active alkaloids and a free radical scavenger from Prosopis species

The biological activity of extracts from the aerial parts of five Argentinian Prosopis species and the exudate of P. flexuosa were assessed for DNA binding, beta-glucosidase inhibition and free radical scavenging effect using the DPPH decoloration assay. DNA binding effect was found mainly in the basic fraction. The alkaloids tryptamine as well as piperidine and phenethylamine derivatives were isolated from the basic extracts. At 0.50 mg/ml, DNA binding activities ranged from 28% for tryptamine to 0-27% for the phenethylamine and 47-54% for the piperidine derivatives. Tryptamine and 2-beta-methyl-3-beta-hydroxy-6-beta-piperidinedodecanol showed a moderate inhibition (27-32%) of the enzyme beta-glucosidase at 100 microg/ml. The exudate of P. flexuosa displayed a strong free radical scavenger effect in the DPPH decoloration assay. The main active constituent was identified as catechin.