Phytogenic compounds from avocado (Persea americana L.) extracts; antioxidant activity,amylase inhibitory activity,therapeutic potential of type 2 diabetes

Diabetes is a worldwide public health disease. Currently, the most effective way to treat diabetes is to mitigate postprandial hyperglycemia by inhibiting carbohydrate hydrolysis enzymes in the digestive system. Plant extracts are rich in bioactive compounds, which can be used in diabetes treatment. This study aims to evaluate the polyphenols content in ethanolic extracts of avocado fruit and leaves (Persea americana Mill.). Additionally, their antioxidant activity using DPPH, while the inhibition ability of α-amylase was examined by reacting different amounts of the extracts with α-amylase compared to acarbose as standard inhibitor. The active compounds were detected in the extracts by LC/MS. The obtained results showed that the leaf extract recorded a significant content of total phenolic compounds compared to the fruit extract (178.95 and 145.7 mg GAE /g dry weight, respectively). The total flavonoid values ??ranged from 32.5 to 70.08 mg QE/g dry weight of fruit and leaves extracts, respectively. Twenty-six phytogenic compounds were detected in leaf and fruit extract by LC/MS. These compounds belong to fatty acids, sterols, triterpenes, phenolic acids, and flavonoids. The antioxidant activity of the extracts is due to the exist of phytogenic compounds, i.e., polyphenols and flavonoids. The antioxidant activity increased in a concentration dependant manner. Avocado fruit extract (1000 µg/mL) scavenged 95% of DPP? while leaf extract rummaged 91.03% of free radicals compared with Vit C and BHT. Additionally, higher α-amylase inhibitory activity was observed in fruit extract than the leaf extract, where the fruit and leaf extract (1000 μg/ml) inhibited the enzyme by 92.13% and 88.95%, respectively. The obtained results showed that the ethanolic extracts of avocado could have a significant impact on human health due to their high content of polyphenols.     

Antifouling activity as a function of population variation in <Emphasis Type="Italic">Sargassum vulgare</Emphasis> from the littoral of Rio de Janeiro (Brazil)

The brown seaweed Sargassum vulgare is abundant along the coast of Rio de Janeiro state. An investigation of the spatial variation of antifouling activity was conducted, in which algae were collected at five locations along the coast of Rio de Janeiro during October 2008. Hexane, dichloromethane, methanol and acetone/water extracts were prepared and screened for their bioactivities against the growth of five strains of marine fouling bacteria, five biofilm-associated microphytobenthic strains and attachment of the mussel Perna perna. The most active were the hexane extracts from Bananal algae that inhibited the growth of all microalgae tested; the methanol and dichloromethane extracts from Mar do Norte, which inhibited Vibrio aestuarianus and Pseudoalteromonas elyakovii and the polyphenol extracts from Ilha de Itacuruçá and Bananal that inhibited mussel attachment, respectively, by 64% and 71% compared to controls.     

Quantitative analysis of polyphenols and antioxidant activity in four Daphne L. species

The content of biologically active phenolic compounds (total polyphenols, tannins, flavonoids, and phenolic acids) were determined using spectrophotometry in four wild Croatian species of Daphne L. in the family Thymelaeaceae (Daphne alpina, D. cneorum, D. laureola, and D. mezereum). The concentration of total flavonoids (TF) was highest in the leaves of these Daphne species (0.12?C0.51% dry herb weight, DW) whereas the content of other phenolic compounds analyzed were highest in the roots, including total polyphenols (TP; 2.71?C19.03% DW), tannins (T; 1.14?C7.39% DW), and total phenolic acids (TPA; 0.12?C0.87% DW). D. alpina contained the highest amount of polyphenols, with the exception of flavonoids, where maximum concentrations were found in D. laureola. We also examined the antioxidant activity of leaf, stem, and root extracts. All extracts analyzed demonstrated high free radical scavenging activity with the highest concentration in the leaf extracts of D. alpina. Leaf extracts of D. cneorum showed the highest antioxidant activity in a ??-carotene bleaching assay.     

Bioactive compounds determination in the callus and hydroalcoholic extracts from Salvia miltiorrhiza and Salvia przewalskii – Preliminary study on their anti-alcoholic activity effects

Studies on hairy roots and callus cultures of Salvia miltiorrhiza and Salvia przewalskii showed that the polysaccharide fraction of yeast extract efficiently stimulated the production of tanshinones in elicited tissues. The aim of our studies was to obtain the biomass of both species enriched in active compounds and to determine tanshinones and phenolic compounds in raw material (callus) and the extracts. Moreover, anti-alcoholic activities of the extracts were tested on one of animal models of alcoholism. It was found that the two Salvia species differed in content of some active compounds. In the hydroalcoholic extracts, an increased content of some compounds was revealed in comparison with the calluses. Only the extract from the S. przewalskii callus (but not from S. miltiorrhiza) reduced significantly an alcohol intake in alcohol-dependent animals, which was correlated with the content of tanshinones (cryptotanshinone, in particular) in the S. przewalskii callus extract, but not with phenolic acids.     

Seasonal variation in antifouling activity of crude extracts of the brown alga Bifurcaria bifurcata (Cystoseiraceae) against cyprids of Balanus amphitrite and the marine bacteria Cobetia marina and Pseudoalteromonas haloplanktis

Previous studies have demonstrated that macroalgae from Brittany (France) contain products with antifouling activity against marine bacteria, fungi, diatoms, seaweeds and mussels. Little is known regarding the ecological function of these compounds and insufficient attention has been paid to evaluating the possible temporal variation in antifouling activity. Studies of chemical defenses in both terrestrial and marine organisms suggest that organisms vary widely in the production of chemical defenses associated with physical (temperature, light) and biological (e.g. grazing pressure) factors, season and geographical location. The present study aimed to investigate the antifouling activity of crude extracts of monthly collections of the brown alga, Bifurcaria bifurcata, against two marine bacteria, Cobetia marina and Pseudoalteromonas haloplanktis, and cypris larvae of the barnacle, Balanus amphitrite. The toxicity of the extracts was determined with a B. amphitrite nauplius assay.The antimicrobial activity of the extracts was found to be subject to seasonal variation, with the highest level of activity recorded from samples collected between April and September. Results of the anti-settlement experiments showed that the extracts of B. bifurcata (when tested from 0 to 100 μg/ml) can be divided into three groups on the basis of their minimum inhibitory concentrations (MICs): (1) extracts from plants collected from September to March reduced settlement at nontoxic concentrations (50-100 μg/ml); (2) extracts from plants collected from April to July (which were the most active extracts) reduced settlement significantly when tested at >5 μg/ml, but were toxic at 100 μg/ml; (3) the extract prepared from plants harvested in August was inhibitory at >25 μg/ml, but was toxic at 100 μg/ml. Toxicity tests on nauplii showed that LC₅₀ values of samples from the September to March collections were >100 μg/ml, demonstrating that they were nontoxic to nauplii. In contrast, samples obtained from the April to August collections were toxic to nauplii; the most toxic ones being from algae collected in May (LC₅₀=55.6 μg/ml) and in June (LC₅₀=38.3 μg/ml).The antifouling activity of extracts thus reached a peak in summer corresponding to maximal values for water temperature, light intensity and fouling pressure. It remains to be investigated whether this activity has an ecological role in the alga.     

Antifouling potential of the marine microalga Dunaliella salina

Marine organisms have usually been viewed as sources of environmentally friendly compounds with antifouling activity. We performed a series of operations to investigate the antifouling potential of the marine microalga Dunaliella salina. For the ethyl acetate crude extract, the antialgal activity was significant, and the EC₅₀ value against Skeletonema costatum was 58.9 μg ml^?1. The isolated purified extract was tested for antifouling activity, the EC ₅₀ value against S. costatum was 21.2 μg ml^?1, and the LC₅₀ against Balanus amphitrite larvae was 18.8 μg ml^?1. Subsequently, both UHR–TOF–MS and GC–MS were used for the structural elucidation of the compounds, and a series of unsaturated and saturated 16- and 18-carbon fatty acids were detected. The data suggested that the fatty acid extracts from D. salina possess high antifouling activity, and could be used as substitutes for potent, toxic antifouling compounds.     

Polyphenolic extracts from pomegranate and watermelon wastes as substrate to fabricate sustainable silver nanoparticles with larvicidal effect against Spodoptera littoralis

The agricultural wastes adversely affect the environment; however, they are rich in polyphenols; therefore, this study aimed to employ polyphenol-enriched waste extracts for silver nanoparticles synthesis, and study the larvicidal activity of silver nanoparticles fabricated by pomegranate and watermelon peels extracts (PPAgNPs and WPAgNPs) against all larval instars of Spodoptera littoralis. The polyphenol profile of pomegranate and watermelon peel extracts (PP and WP) and silver nanoparticles was detected by HPLC. The antioxidant activity was estimated by DPPH, and FARP assays and the antimicrobial activity was evaluated by disc assay. The Larvicidal activity of AgNPs against Egyptian leaf worm was performed by dipping technique. The obtained AgNPs were spherical with size ranged 15–85 nm and capped with proteins and polyphenols. The phenolic compounds in silver nanoparticles increased about extracts; therefore, they have the best performance in antioxidant/reducing activity, and inhibit the growth of tested bacteria and yeast. The PPAgNPs were the most effective against the first instar larvae instar (LC₅₀ = 68.32 µg/ml), followed by pomegranate extract with (LC₅₀ = 2852 µg/ml). The results indicated that obvious increase in polyphenols content in silver nanoparticles enhance their larvicidal effect and increasing mortality of 1^st larval of S. littoralis Egyptian leafworms causing additive effect and synergism. We recommend recycling phenolic enriched agricultural wastes in producing green silver nanoprticles to control cotton leafworm that causes economic loses to crops.     

Phenolic production and antioxidant properties of some Macedonian medicinal plants

Investigations have been made to study the production of phenolic compounds (total phenolics, flavonoids and phenylpropanoids) and total antioxidant capacity in 27 Macedonian traditional medicinal plants to improve its potential as a source of natural antioxidants. Antioxidant potential of plant extracts was analyzed by five different assays: cupric reducing antioxidant capacity (CUPRAC), phosphomolybdenum method (PM), reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH^·) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS^·+) radical scavenging activity. Origanum vulgare extract consistently exhibited the highest content of phenolic compounds and the strongest antioxidant capacity based on the tests performed, and can be proposed as a promising source of natural antioxidants. Melissa officinalis and Salvia ringens were also identified as valuable sources of antioxidant compounds. A positive linear correlation between antioxidant activity and total phenolics, flavonoids and phenylpropanoids indicates that these compounds are likely to be the main antioxidants contributing to the observed activities of evaluated plants. These findings suggest that the medicinal plants studied in this paper are good sources of bioactive compounds for the food and pharmaceutical industries.     

Antifouling potentials of eight deep-sea-derived fungi from the South China Sea

Marine-derived microbial secondary metabolites are promising potential sources of nontoxic antifouling agents. The search for environmentally friendly and low-toxic antifouling components guided us to investigate the antifouling potentials of eight novel fungal isolates from deep-sea sediments of the South China Sea. Sixteen crude ethyl acetate extracts of the eight fungal isolates showed distinct antibacterial activity against three marine bacteria (Loktanella hongkongensis UST950701–009, Micrococcus luteus UST950701–006 and Pseudoalteromonas piscida UST010620–005), or significant antilarval activity against larval settlement of bryozoan Bugula neritina. Furthermore, the extract of Aspergillus westerdijkiae DFFSCS013 displayed strong antifouling activity in a field trial lasting 4 months. By further bioassay-guided isolation, five antifouling alkaloids including brevianamide F, circumdatin F and L, notoamide C, and 5-chlorosclerotiamide were isolated from the extract of A. westerdijkiae DFFSCS013. This is the first report about the antifouling potentials of metabolites of the deep-sea-derived fungi from the South China Sea, and the first stage towards the development of non- or low-toxic antifouling agents from deep-sea-derived fungi.     

Phlorotannins as Radical Scavengers from the Extract of Sargassum ringgoldianum

To screen algal phlorotannins with antioxidative activities, 50% ethanol extracts of 25 Japanese marine algae were evaluated. Scavenging activity against superoxide anion radicals was frequently found with a high content of total phenolic compounds. Among these, the extract from the brown seaweed, Sargassum ringgoldianum, showed the strongest scavenging activity. The active fraction contained a mixture of high molecular weight polyphenols, phlorotannins that were found to be polymerized bifuhalol, as analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The scavenging activity of the fraction against superoxide anion radicals was estimated to be 1.0 μg/ml (IC₅₀), which were approximately five times stronger than that of catechin.     

Total phenolic content and antioxidant activity of plants used in traditional Romanian herbal medicine

A number of herbal plants from Romania widely used as natural food additives or for health promotion in traditional medicine were investigated for their antioxidant activity. Methanol extracts were obtained from plants belonging to the Lamiaceae family (lavender Lavandula angustifolia L.; lemon balm Melissa officinalis; sage Salvia officinalis; oregano Origanum vulgare L.; rosemary Rosmarinus officinalis L.; thyme Thymus vulgaris L.; mullein Verbascum phlomoides; mint Mentha longifolia), Clusiaceae family (St John’s wort Hypericum perforatum L.), and Compositae family (elecampane Inula helenium). Total phenolic concentration was determined using the Folin-Ciocalteu phenol reagent method, while total flavonoids were measured using the aluminium chloride colorimetric method. Relationships between total antioxidant activity and composition of plant extracts were evaluated. Origanum vulgare extract showed the highest antioxidant activity and total phenolic content compared to the other plants extracts. A positive correlation was observed between total antioxidant activity and total phenolic content of the analyzed extracts.     

<Emphasis Type="Italic">Camellia sinensis</Emphasis> increased apoptosis on U2OS osteosarcoma cells and wound healing potential on NIH3T3 fibroblast cells

Camellia sinensis (Cs) is a plant which is rich in polyphenols and has antioxidant, antiinflammatory, antimutagenic, anticarcinogenic and antibacterial activities. In this study, two different methanol extracts (Cs-I and Cs-II) were prepared from the leaf of C. sinensis in order to investigate the wound healing and anticancer activities. Total phenolic content and antioxidant activity of the extracts were determined. Wound healing effects of Cs extracts were evaluated by using Masson’s Trichrome Tecnique on NIH3T3 fibroblast cells. Cytotoxic and apoptotic effects of the extracts were determined by MTT and AnnexinV-PI assays on U2OS osteosarcoma cells. Total phenolic contents and antioxidant activities of the extracts were almost the same. The highest concentration (60 µg/mL) of the extracts showed significant cytotoxic and apoptotic effects on U2OS cells. Especially, the highest apoptotic effect was determined with 60 µg/mL Cs-I extract. Significant wound healing potential on NIH3T3 fibroblast cells were determined especially with low extract concentrations (0.5, 1 and 5 µg/mL), while high extract concentrations showed significant anticancer effects. As a result, two Cs leaf extracts exhibited important apoptotic properties and both have wound healing potential. However, the Cs-I extract was found more effective on apoptotic osteosarcoma cell death and has an increased wound healing potential than the Cs-II extract.     

Phytochemical Profile and Nutraceutical Value of Old and Modern Common Wheat Cultivars

Among health-promoting phytochemicals in whole grains, phenolic compounds have gained attention as they have strong antioxidant properties and can protect against many degenerative diseases. Aim of this study was to profile grain phenolic extracts of one modern and five old common wheat (Triticum aestivum L.) varieties and to evaluate their potential antiproliferative or cytoprotective effect in different cell culture systems.Wheat extracts were characterized in terms of antioxidant activity and phenolic composition (HPLC/ESI-TOF-MS profile, polyphenol and flavonoid contents). Results showed that antioxidant activity (FRAP and DPPH) is mostly influenced by flavonoid (both bound and free) content and by the ratio flavonoids/polyphenols. Using a leukemic cell line, HL60, and primary cultures of neonatal rat cardiomyocytes, the potential antiproliferative or cytoprotective effects of different wheat genotypes were evaluated in terms of intracellular reactive oxygen species levels and cell viability. All tested wheat phenolic extracts exerted dose-dependent cytoprotective and antiproliferative effects on cardiomyocytes and HL60 cells, respectively. Due to the peculiar phenolic pattern of each wheat variety, a significant genotype effect was highlighted. On the whole, the most relevant scavenging effect was found for the old variety Verna. No significant differences in terms of anti-proliferative activities among wheat genotypes was observed. Results reported in this study evidenced a correspondence between the in vitro antioxidant activity and potential healthy properties of different extracts. This suggests that an increased intake of wheat grain derived products could represent an effective strategy to achieve both chemoprevention and protection against oxidative stress related diseases.     

In vitro antioxidant,antimicrobial and antiproliferative studies of four different extracts of Orthosiphon stamineus,Gynura procumbens and Ficus deltoidea

BackgroundMedicinal plants are important source of drugs with pharmacological activities. Therefore, there is always rising demands to discover more therapeutic agents from various species. Orthosiphon stamineus, Gynura procumbens and Ficus deltoidea are high valued medicinal plants of Malaysia contain rich source of phenolic and flavonoid compounds. The aims of the present study were to evaluate anti-oxidant, antimicrobial and anti-proliferative effects on A549, HePG2 and MCF7 cell lines of four different extracts of Orthosiphon stamineus, Gynura procumbens and Ficus deltoidea.MethodologyThe leaves of all selected plants were extracted with methanol, chloroform, ethyl acetate and butanol separately with simple cold maceration. Antioxidant activity of all crude extracts were quantitatively measured against DPPH and Ferric Reducing Assay. Antimicrobial evaluation was done by Microdilution and MTT assay and antipoliferative activity of all extracts of selected plant were evaluated against A549, HePG2 and MCF7 cell lines.ResultsResults showed that methanol extract exhibited highest percentage free radical scavenging activity of almost all extracts of selected plants. Antimicrobials results showed chloroform and methanol extracts of O. stamineus extract were the two most active extracts against resistant MRSA but not S. aureus. Only methanol extract of G. procumbens showed antimicrobial activity against the tested pathogens. Chloroform and methanol extracts of F. deltoidea elicited antimicrobial activity against S. aureus but not MRSA. Antiproliferative activity against three tested cell lines results showed that ethyl acetate extract of O. stamineus showed good effect whereas methanol extract of F. deltoidea and G. procumbens exhibited good antiproliferative activity.ConclusionsThe results of the present investigation demonstrated significant variations in the antioxidant, antimicrobial and antiproliferative effects of different solvent extracts. These data could be helpful in isolation of pure potent compounds with good biological activities from the extracts of plants.     

Evaluation of phenolic profile,antioxidant and anticancer potential of two main representants of Zingiberaceae family against B164A5 murine melanoma cells

Background

Curcuma longa Linnaeus and Zingiber officinale Roscoe are two main representatives of Zingiberaceae family studied for a wide range of therapeutic properties, including: antioxidant, anti-inflammatory, anti-angiogenic, antibacterial, analgesic, immunomodulatory, proapoptotic, anti-human immunodeficiency virus properties and anticancer effects. This study was aimed to analyse the ethanolic extracts of Curcuma rhizome (Curcuma longa Linnaeus) and Zingiber rhizome (Zingiber officinale Roscoe) in terms of polyphenols, antioxidant activity and anti-melanoma potential employing the B164A5 murine melanoma cell line.

Results

In order to evaluate the total content of polyphenols we used Folin-Ciocâlteu method. The antioxidant activity of the two ethanolic extracts was determined by DPPH assay, and for the control of antiproliferative effect it was used MTT proliferation assay, DAPI staining and Annexin-FITC-7AAD double staining test. Results showed increased polyphenols amount and antioxidant activity for Curcuma rhizome ethanolic extract. Moreover, 100 μg/ml of ethanolic plant extract from both vegetal products presented in a different manner an antiproliferative, respectively a proapoptotic effect on the selected cell line.

Conclusions

The study concludes that Curcuma rhizome may be a promising natural source for active compounds against malignant melanoma.     

Antimicrobial activity of Brazilian propolis extracts against rumen bacteria in vitro

The antimicrobial activity of three Brazilian propolis extracts was evaluated on bacterial strains representing major rumen functional groups. The extracts were prepared using different concentrations of propolis and alcohol, resulting in different phenolic compositions. The propolis extracts inhibited the growth of Fibrobacter succinogenes S85, Ruminococcus flavefaciens FD-1, Ruminococcus albus 7, Butyrivibrio fibrisolvens D1, Prevotella albensis M384, Peptostreptococcus sp. D1, Clostridium aminophilum F and Streptococcus bovis Pearl11, while R. albus 20, Prevotella bryantii B₁4 and Ruminobacter amylophilus H18 were resistant to all the extracts. The inhibited strains showed also different sensitivity to propolis; the hyper-ammonia-producing bacteria (C. aminophilum F and Peptostreptococcus sp. D1) being the most sensitive. Inhibition of hyper-ammonia-producing bacteria by propolis would be beneficial to the animal. The extract containing the lowest amount of phenolic compounds (LLOS C3) showed the lowest antimicrobial activity against all the bacteria. The major phenolic compounds identified in the propolis extracts (naringenin, chrysin, caffeic acid, p-coumaric acid and Artepillin C) were also evaluated on four sensitive strains. Only naringenin showed inhibitory effect against all strains, suggesting that naringenin is one of the components participating to the antibacterial activity of propolis.     

GC/MS and LC/MS analysis,and antioxidant and antimicrobial activities of various solvent extracts from Mirabilis jalapa tubers

The antioxidant and antimicrobial activities of various solvent extracts from Mirabilis jalapa tubers (MJT) were investigated using various in vitro assays. The total phenolic and flavonoid contents varied from 21.45 to 364.6 mg gallic acid equivalent (GAE)/g dried extract and 5.2 to 71.6 mg quercetin/g dried extract, respectively. Water extract of MJT was the most potent antioxidant in all assays used, followed by methanol extract. The five solvent extracts were screened for antibacterial and antifungal activities. Water extract was the most effective with minimum inhibitory concentration <200 μg/ml against Staphylococcus aureus, Micrococcus luteus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus cereus and Enterococcus faecalis. Only water extract showed antifungal activity against Aspergillus niger, Fusarium solani, Fusarium oxysporium and Fusarium granularium. GC/MS analysis of MJT dichloromethane and methanol extracts showed that oleic acid and β-sitosterol were, respectively, the major compounds. LC/MS analysis of the aqueous extract showed a high content of flavanol and flavonol compounds. Phenolic acids such as ferulic and caffeic acid were also detected.To our knowledge, this is the first report on the chemical composition, and antioxidant and antimicrobial activities of phenolic extracts from M. jalapa tubers (MJT). The results of the present work indicate that MJT extracts could be used as natural antioxidant and antimicrobial agents in the food preservation and human health.     

Antibacterial activity of wine phenolic compounds and oenological extracts against potential respiratory pathogens

Aims: To investigate the effect of seven wine phenolic compounds and six oenological phenolic extracts on the growth of pathogenic bacteria associated with respiratory diseases (Pseudomonas aeruginosa, Staphylococcus aureus, Moraxella catarrhalis, Enterococcus faecalis, Streptococcus sp Group F, Streptococcus agalactiae and Streptococcus pneumoniae). Methods and Results: Antimicrobial activity was determined using a microdilution method and quantified as IC₅₀. Mor. catarrhalis was the most susceptible specie to phenolic compounds and extracts. Gallic acid and ethyl gallate were the compounds that showed the greatest antimicrobial activity. Regarding phenolic extracts, GSE (grape seed extract) and GSE‐O (oligomeric‐rich fraction from GSE) were the ones that displayed the strongest antimicrobial effects. Conclusions: Results highlight the antimicrobial properties of wine phenolic compounds and oenological extracts against potential respiratory pathogens. The antimicrobial activity of wine phenolic compounds was influenced by the type of phenolic compounds. Gram‐negative bacteria were more susceptible than Gram‐positive bacteria to the action of phenolic compounds and extracts; however, the effect was species‐dependent. Significance and Impact of Study: The ability to inhibit the growth of respiratory pathogenic bacteria as shown by several wine phenolic compounds and oenological extracts warrants further investigations to explore the use of grape and wine preparations in oral hygiene.     

Antimicrobial activity and phytochemical screening of Ocimum americanum L extracts against pathogenic microorganisms

The aim of the present study is to assess the antimicrobial activities of various leaf extracts of Ocimum americanum were tested against pathogenic microorganisms. Preparation of different extracts viz., aqueous, acetone, ethyl acetate and methanol through soxhlet extraction method. Various extracts were investigated against MTCC strains of Bacillus cereus, Clostridium penfrigens, Klebsilla pnemoniae, Salmonella paratyphi, Candida albicans and Aspergillus niger by agar well diffusion and disc diffusion methods. Minimum inhibitory concentration (MIC), Minimum Bactericidal/Fungicindal Concentration (MBC/MFC) were determined through micro dilution method. Elucidation of phytochemicals and functional groups were observed by HPLC and FT-IR respectively. Ethyl acetate leaf extract of O.americanum showed significant antimicrobial activity against the all tested pathogens in agar well diffusion method in which B.cereus (17 mm) was observed high zone of inhibition. Whereas lowest inhibition was observed in aqueous extract against C.pentrigens (7 mm). The ranges of MIC values from 0.78 μg/ml to 50 μg/ml and MBC/MFC 1.56 μg/ml to 50 μg/ml were observed. Phytochemicals such as alkaloids, steroids, saponins, flavonoids, tannins, terepenes, phenolic compounds cardiac glycosides were detected. Saponinns, flavonoids, tannins, phenolic compounds were observed in only ethyl acetate leaf extracts. Functional group of the leaf extracts was exhibited by FTIR and HPLC analysis of the ethyl acetate leaf extract was elutated at six peaks. Based on the results we concluded that ethyl acetate leaf extract of O.americanum has proved to be potentially effective than the other extracts. Therefore, ethyl acetate leaf extract of O.americanum could act as antimicrobial agent and further studies are recommended for isolation of compounds and toxicological studies.     

Antifouling activity against barnacle cypris larvae: Do target species matter (Amphibalanus amphitrite versus Semibalanus balanoides)?

Larvae of many benthic invertebrates settle on surfaces where they metamorphose into juveniles if suitable substrata are available, and are responsible for the major costs of biofouling. When assessing new formulations or compounds for potential antifouling (AF) application, constraints such as seasonal availability may restrict most bioassays to relatively few taxa and species. For example, amongst barnacles, Amphibalanus amphitrite is popular as a test organism but is it really representative of other barnacle species? In order to test this hypothesis, we have chosen to work with marine natural extracts as a probe. Indeed, one substitution technology to toxic metal-based coatings to control fouling is the development of AF coatings with active compounds derived from marine organisms or analogues of the lead compounds. In this study, the AF activity and toxicity of extracts from 30 algae from the North East Atlantic coast were investigated for their potential anti-settlement activities against larvae of two species of barnacle, A. amphitrite and Semibalanus balanoides. As a trend, most of the active extracts displayed activity towards S. balanoides, only few displayed targeted activity against A. amphitrite, or against both species. In order to better understand if this tendency could be linked to chemical ecology, surface extracts were prepared on a selection of species. The results highlight that surface extracts of algae all displayed highest levels of activity than total extracts when tested on S. balanoides. This difference illustrates that specific compounds in their ecological context can have potentially a better efficacy on target species.