The Phenolic Contents and Antimicrobial Activities of Some Marine Algae from the Mediterranean Sea (Algeria)

In this study, three marine algae collected from western coast of algerian mediteranean sea (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) were tested using the agar-well diffusion method for their production of antibacterial and antifungal agents on various organisms that cause diseases of humans and plants (Eschirichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Salmonella sp, Candida albicans, and Penicillium sp.). The total phenol content and antimicrobial activity were determined using different crude seaweeds extracts (methanol, diethylether, and chloroform). The results show that the chloroform extracts of (Ulva lactuca and Corallina elongata) had the highest activity against E. coli and Salmonella sp. The methanol extract obtained from (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) showed antifungal activity for Candida albicans. The results of the study revealed that the seaweeds from Algeria appear to have immense potential as a source of antibacterial and antifungal compounds; they can be used in treating diseases caused by these organisms.     

Seasonal variations in the production of antifungal substances by some dictyotales (brown algae) from the french mediterranean coast

Hexane extracts of some algae belonging to the Dictyotales collected over a 12 month period were tested for their antifungal activity using human pathogenic fungi (yeasts, moulds and dermatophytes) and phytopathogenic fungi responsible for diseases in Mediterranean plants and trees. The three algal species tested (Dictyota dichotoma, Dictyota dichotoma var. implexa, Dilophus spiralis) exhibited a wide spectrum of antifungal activity which varied during the seasons.     

Antimicrobial activity of broccoli (Brassica oleracea var. italica) cultivar Avenger against pathogenic bacteria,phytopathogenic filamentous fungi and yeast

Aims

The objective of this study was to show whether the edible part of broccoli has antibacterial and antifungal activity against micro‐organism of importance in human health and vegetable spoilage, and to test if this effect was partially due to antimicrobial peptides (AMPs).

Methods and Results

Crude extracts were obtained from florets and stems of broccoli cultivar Avenger and the inhibitory effect was demonstrated against pathogenic bacteria (Bacillus cereus, Staphylococcus xylosus, Staphylococcus aureus, Shigella flexneri, Shigella sonnei, Proteus vulgaris), phytopathogenic fungi (Colletotrichum gloeosporioides, Asperigillus niger) and yeasts (Candida albicans and Rhodotorula sp.). It was shown that samples treated with proteolytic enzymes had a reduction of approximately 60% in antibacterial activity against Staph. xylosus, suggesting that proteinaceous compounds might play a role in the inhibitory effect. Antimicrobial components in crude extracts were thermoresistant and the highest activity was observed under acidic conditions. It was shown that antifungal activity of broccoli's crude extracts might not be attributed to chitinases.

Conclusions

Organic broccoli cultivar Avenger has antimicrobial activity against pathogenic bacteria, yeast and phytophatogenic fungi. Data suggest that this effect is partially due to AMPs.

Significance and Impact of the Study

Broccoli's crude extracts have activity not only against pathogenic bacteria but also against phytophatogenic fungi of importance in agriculture. We suggest for first time that the inhibitory effect is probably due to AMPs.     

Resources and possibilities for exploitation of North Adriatic seaweeds

Suggestions for a small-scale exploitation of seaweeds in the northern Adriatic are given along with a survey of the fresh weight biomass and chemical composition of individual species. The intertidal is occupied by Fucus virsoides. In polluted sites, it is replaced by seasonal annuals. Cystoseira species are dominant in the upper subtidal and represent the major part of seaweed resources in this area. In polluted sites they are replaced by Halopteris scoparia and Dictyota dichotoma. Peaks in biomass were found in spring in the upper water layers and in early summer lower in the subtidal. The protein content of most species exhibited maxima in spring. Elevated values were found in plants from polluted and estuarine habitats.     

Broad-spectrum antibacterial and antifungal properties of certain traditionally used Indian medicinal plants

Ethanolic extracts of 22 traditionally used Indian medicinal plants were studied for their antimicrobial activity against seven bacteria (Staphylococcus aureus, Salmonella typhimurium, S. paratyphi, S. typhi, E. coli, Shigella dysenteriae and Pseudomonas aeruginosa) and five filamentous fungi (Aspergillus niger, Alternaria alternata, Fusarium chlamydosporum, Rhizoctonia bataticola and Trichoderma viride) and a yeast Candida albicans of clinical origin. Of these, 16 plant extracts showed varied level of antibacterial activity against one or more test bacteria. Similarly antifungal and anticandidal activity was detected among 17 and 9 plant extracts respectively. Broad-spectrum antimicrobial activity (both antibacterial and antifungal) was detected among crude extracts of Bryophyllum pinnatum (leaves), Caesalpinia bonducella (seeds), Delonix regia (flower), Hedychium spicatum (fruits), Mangifera indica (leaves), Murraya coenigii (leaves) and Syzgium cumini (seeds). Similarly extracts of Cichorium intybus (roots), Ficus religiosa (leaves) and Trigonella foenum-graecum (leaves) demonstrated more antibacterial activity with less antifungal activity. On the other hand Pistacia integerrima (stems) and Rheum emodi (roots) demonstrated more antifungal activity with less antibacterial activity.     

Antibacterial activity of<Emphasis Type="Italic">Ulva lactuca</Emphasis> against methicillin-resistant<Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA)

Thein vitro antimicrobial activity of the marine green algaeUlva lactuca was examined against gram-positive bacteria, gram-negative bacteria, and a fungus. The ethyl-ether extract of algae exhibited a broad-spectrum of antibacterial activity. but not antifungal activity againstCandida albicans. In particular, theU. lactuca extract showed strong activity aganst the bacterium methicillin-resistantStaphylococcus aureus (MRSA). This result confirms the potential use of seaweed extracts as a source of antibacterial compounds or as a health-promoting food for aquaculture.     

Evaluation of antimicrobial activity of the lichens <Emphasis Type="Italic">Lasallia pustulata,Parmelia sulcata,Umbilicaria crustulosa</Emphasis>, and <Emphasis Type="Italic">Umbilicaria cylindrica</Emphasis>

The antimicrobial properties of acetone, methanol, and aqueous extracts of the lichens Lasallia pustulata, Parmelia sulcata, Umbilicaria crustulosa, and Umbilicaria cylindrica were studied comparatively in vitro. Antimicrobial activities of the extracts of different lichens were estimated by the disk diffusion test for Gram-positive bacteria, Gram-negative bacteria, and fungal organisms, as well as by determining the MIC (minimal inhibitory concentration). The obtained results showed that the acetone and methanol extracts of Lasallia pustulata, Parmelia sulcata, and Umbilicaria crustulosa manifest antibacterial activity against the majority of species of bacteria tested, in addition to selective antifungal activity. The MIC of lichen extracts was lowest (0.78 mg/ml) for the acetone extract of Lasallia pustulata against Bacillus mycoides. Aqueous extracts of all of the tested lichens were inactive. Extracts of the lichen Umbilicaria cylindrica manifested the weakest activity, inhibiting only three of the tested organisms.     

Evaluation of the nutritional profile and antioxidant and anti-cholinesterase activities of Padina gymnospora (Phaeophyceae)

The use of cholinesterase inhibitors and antioxidants is currently considered as an effective therapeutic strategy for the treatment of Alzheimer’s disease (AD). There is also a growing trend to use nutraceuticals for cognitive impairment. Since natural product-based drugs offer better hope for the treatment of AD, the present study was aimed at evaluating the nutritional profile of the brown seaweed Padina gymnospora and investigating the antioxidant and inhibitory effect of different solvent extracts of P. gymnospora on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. The nutritional profile of P. gymnospora includes large amounts of carbohydrate, protein, lipid, proline, chlorophyll, fibre, minerals, fatty acids and amino acids, along with antioxidants such as vitamins C and E. Antioxidant activities of various solvent extracts of P. gymnospora were assessed by the DPPH scavenging assay, nitric oxide scavenging assay, reducing power assay and FRAP assay. Acetone extracts showed significant DPPH radical and nitric oxide scavenging activity with IC₅₀ values of 402 ± 9.12 and 441 ± 48.16 µg ml^–1 respectively and aqueous extracts had better reducing potential. Among the different solvent extracts, the acetone extract showed the highest inhibitory activity with IC₅₀ values <150 µg ml^–1 for both AChE and BuChE. Qualitative phytochemical screening of P. gymnospora revealed the presence of flavonoids and cardiac glycosides. Overall the results suggest that the seaweed Padina gymnospora may be a good nutraceutical candidate for discovering drugs against AD.     

Screening of antifungal activity of various plant leaves extracts from Indian plants

The present study was designated to evaluate the antifungal activity and to root out the antifungal plant leaf extracts from this Indian folk-flore. The in vitro antifungal assay was performed by agar diffusion test and minimum inhibitory concentration (MIC) for hexane, ethyl acetate, methanol and distilled water plant leaf extracts. Extraction of 17 different plant leaves was carried out in different solvents such as hexane, ethyl acetate, methanol and distilled water. Among them extractive yield of methanol was maximum than the rest of the three solvents. These extracts were screened for their antifungal activity against nine different fungi. Among these ethyl acetate extracts of Adhatoda vasica, Ocimum sanctum and Holoptelea integrifolia exhibited maximum antifungal activity against Alternaria sp., Aspergillus parasi, Aspergillus nidulans, Trichoderma harzianum and Aspergillus flavus with MIC of 80, 40 and 20 ppm against Aspergillus nidulans and Alternaria sp. Ethyl acetate extracts showed promising antifungal activity against Adhatoda vasica, Ocimum sanctum and Holoptelea integrifolia against Aspergillus nidulans, and Alternaria sp. might be applicable as fungicide against fungal plants disease.     

Antibacterial activity of marine macroalgae against fish pathogenic Vibrio species

In mariculture, diseases of microbial origin can cause significant economic losses worldwide; the evolution of microorganism resistance to antibiotics has resulted in a growing need for new antibacterial compounds that are effective in veterinary medicine and characterized by limited undesirable side effects. Increased attention has recently been turned to seaweeds as a promising source for metabolites with antimicrobial activity. Vibriosis is a common disease, caused by bacteria of the genus Vibrio, that can result in high mortality in aquaculture. The aim of this study was to identify seaweeds with antibacterial activity against some pathogenic Vibrio species, in order to identify a possible alternative to the commonly used antibiotics in aquaculture. Chloroform/methanol lipidic extracts of six seaweed species (Chaetomorpha linum, Cladophora rupestris, Gracilaria dura, Gracilaria gracilis, Gracilariopsis longissima, Ulva prolifera) were tested for their antibacterial activities against six fish pathogenic Vibrio species using the disc diffusion method. Different susceptibilities to lipidic algal extracts were observed. All six of the seaweed extracts tested demonstrated inhibition of Vibrio ordalii. The best was that from Gracilariopsis longissima, showing activity against Vibrio ordalii, Vibrio salmonicida, Vibrio alginolyticus and Vibrio vulnificus. The results confirmed the potential use of seaweed extracts as a source of antibacterial compounds or as a health-promoting feed for aquaculture.     

蒜头果内生真菌次生代谢产物抑制人类致病菌活性的研究

蒜头果是我国特有的单种属稀有树种,为了进一步开发利用蒜头果树皮内生真菌的抗菌活性化合物,该研究对来自蒜头果的植物内生真菌(白黄笋顶孢霉、哈茨木霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌、朱黄青霉、Xenoacremonium recifei、Xylaria feejeensis)进行液体培养,10 d后回收培养液并用乙酸乙酯萃取获得初提物,采用抑菌圈法检测蒜头果内生真菌初提物抑菌活性,同时测定了最低抑菌浓度(MIC)。结果表明:白黄笋顶孢霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌均有抑菌活性,大棘黑团孢、斑污拟盘多毛孢、淡紫紫孢菌的初提物均对缓慢芽孢杆菌、无乳链球菌和藤黄微球菌有明显抗菌活性,最低抑菌浓度在1.562 5~6.25 mg·m L~(-1)之间。这说明蒜头果树皮内生真菌的次生代谢产物具有抗菌活性,各内生真菌次生代谢产物的抗菌效果不同。     

Chemical Composition and Biological Activities of Metania and Drulia (Metaniidae) Freshwater Sponges from Amazonia

Sponges from freshwater environments, unlike marine's, are poorly known producers of natural compounds with medicinal purposes. Amazonian sponges produce massive large specimens and are widely spread, taxonomically diverse and their metabolites could represent a new frontier on unusual natural products to treat diseases such as Alzheimer's and Malaria. Species of Metania and Drulia (Metaniidae) genera are major contributors to the fauna of Amazonian freshwater sponges. Methanolic extracts from several species from these genera had their inhibitory activities evaluated in vitro, for parasite Plasmodium falciparum and acetyl and butyrylcholinesterase enzymes (AChE and BChE). All extracts were able to inhibit AChE, although no activity was observed towards BChE. Drulia uruguayensis extract was the most potent, inhibiting AChE with IC₅₀=1.04 mg/mL. For antiplasmodial activity, all species showed inhibition to P. falciparum, but Metania reticulata being the most efficient with IC₅₀=2.7 μg/mL. Mass spectrometry analyses evidenced the presence of fatty acids and sterols in active extracts.     

Inhibitory Effects of Some Spice and Herb Extracts Against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii

Seventeen spice and medicinal plant extracts (methanol and chloroform) were assayed for their antimicrobial activity against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii. In general, all of the tested extracts were able, to a different extent, to inhibit the growth of the selected Arcobacter species. Cinnamon, bearberry, chamomile, sage and rosemary extracts showed strong antimicrobial activity toward arcobacter strains tested. Overall, the methanol extracts showed better activity than the chloroform extracts (P < 0.05); however, enhanced antibacterial activity of chloroform extracts of cinnamon and rosemary has been observed in comparison with their methanol counterparts. The inhibitory dose of the most active extracts (the diameter of zone of inhibition ≥ 20 mm) was determined using the disc-diffusion method as well.     

Comparison of cytokinin- and auxin-like activity in some commercially used seaweed extracts

Six commercially used seaweed extracts were tested for cytokinin- and auxin-like activity using the soybean callus bioassay and the mung bean rooting bioassay respectively. All the seaweed extracts tested showed cytokinin-like activity. Seamac caused the most callus growth with activity being concentrated at R _f 0.9 which co-chromatographed withiso-pentenyladenine and its riboside. The other five seaweed extracts yielded activity at R _f 0.7–0.8. This co-chromatographed with zeatin and zeatin riboside. All the seaweed extracts tested improved rooting of mung beans. Kelpak made fromEcklonia maxima (Osbeck) Papenf. gave the best rooting response.     

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.     

Seasonal fluctuations in soil phenolics of a coniferous forest: effects on seed germination of different coniferous species

This study examined seasonal variations in the content of water-soluble phenolics extracted from litter and Ah horizon of forest soil under Pinus laricio Poiret trees. After having identified and quantified different phenolics, the effects of seasonal phenolic extracts, single phenolic acids and synthetic phenol mixtures on seed germination of Pinus laricio Poiret, Pinus pinaster Aiton and Pinus halepensis Mill. were evaluated, and the activity of phenolics on the main enzymes involved in the glyoxylate cycle was tested. The results indicated a seasonal variation of phenol content in soil, with largest concentrations of water-soluble phenolic acids in autumn and smallest concentrations in summer. Addition of phenol extracts to germination medium reduced seed germination showing phytotoxic effects which differed, depending on the species and the fractions tested. Phenols extracted from litter and Ah horizon in autumn and winter, vanillic acid, and synthetic mixtures reproducing phenols extracted from soil in winter inhibited seed germination of Pinus laricio, pinaster and halepensis more than other treatments. A greater inhibitory effect was observed on seed germination of Pinus pinaster and halepensis compared to Pinus laricio. The phenols also had the greatest inhibitory effect on glyoxylic enzyme activities. Section Editor: H. Lambers     

具抗菌及乙酰胆碱酯酶抑制活性珊瑚真菌的筛选

为开发利用珊瑚真菌资源,以徐闻珊瑚保护区珊瑚样品中分离鉴定的43株海洋真菌为研究对象,采用双层平板法和Ellman法分别对其进行抗菌和乙酰胆碱酯酶（AChE）抑制活性筛选。结果显示,43株菌株至少对一种指示菌有抑制作用,且有12株菌株对革兰阳性菌和革兰阴性菌均表现出不同程度的抗菌活性,抗菌谱较广;当浓度为1 mg/mL时,有8株菌株的发酵液提取物对乙酰胆碱酯酶的抑制率达到50%以上。其活性菌株中曲霉属(Aspergillus)为优势属。     

Anticandidial and anticryptococcal activity of <Emphasis Type="Italic">Euphorbia fusiformis</Emphasis>, a rare medicinal plant

The present work demonstrates the screening of extracts of the rare medicinal herb Euphorbia fusiformis for antifungal activity. The main aim was to investigate its antifungal properties against Candida albicans and Cryptococcus neoformans, the causative agents of human candidiasis and cryptococcosis, respectively. Aqueous and organic solvent extracts from the leaves and rootstock of the plant were tested against the fungi by the well-in-agar method. Almost all the organic solvent extracts exhibited an inhibitory effect against C. albicans and to some extent on C. neoformans, except for the aqueous extracts, which had no effect. The combined formulations of the extracts also had better activity against C. albicans than C. neoformans. This study thus concludes by demonstrating the antifungal properties of E. fusiformis and also the potential research in identifying the active principles, which may have future therapeutic value.     

Geographic variation in feeding preference of a generalist herbivore: the importance of seaweed chemical defenses

The ecological impacts of generalist herbivores depend on feeding preferences, which can vary across and within herbivore species. Among mesoherbivores, geographic variation in host use can occur because host plants have a more restricted geographic distribution than does the herbivore, or there is local evolution in host preference, or both. We tested the role of local evolution using the marine amphipod Ampithoe longimana by rearing multiple amphipod populations from three regions (subtropical Florida, warm-temperate North Carolina and cold-temperate New England) and assaying their feeding preferences toward ten seaweeds that occur in some but not all regions. Six of the ten seaweeds produce anti-herbivore secondary metabolites, and we detected geographic variation in feeding preference toward five (Dictyota menstrualis, Dictyota ciliolata, Fucus distichus, Chondrus crispus and Padina gymnospora, but not Caulerpa sertularioides). Amphipod populations that co-occur with a chemically-rich seaweed tended to have stronger feeding preferences for that seaweed, relative to populations that do not co-occur with the seaweed. A direct test indicated that geographic variation in feeding preference toward one seaweed (D. ciliolata) is mediated by feeding tolerance for lipophilic secondary metabolites. Among the four seaweeds that produce no known secondary metabolites (Acanthophora, Ectocarpus, Gracilaria and Hincksia/Feldmannia spp.), we detected no geographic variation in feeding preference. Thus, populations are more likely to evolve greater feeding preferences for local hosts when those hosts produce secondary metabolites. Microevolution of feeding behaviors of generalist marine consumers likely depends on the availability and identity of local hosts and the strength of their chemical defenses.     

Ichtyotoxic activity of extracts from Mexican marine macroalgae

Seventy-three species of macroalgae from the Mexican Pacific, Atlantic and Caribbean coast were screened for ichtyotoxic activity. Ethanolic, acetonic and aqueous extracts were prepared and tested against the fish Carassius auratus. The extracts were classified on the basis of their effects as: toxic if the fish died in two hours or less; moderately toxic, if the organism behaved abnormally but death did notoccur, and non-toxic if the fish did not display any change. 79% species were ichtyotoxic to some degree. Extracts of 39 species were toxic, with at least one extract with lethal effects, 19 were moderately toxic and 15 species were non-toxic. Only the extracts ofDictyota bartayresiana, Dictyota cervicornis,Lobophora variegata, Bryothamnion triquetrum and Laurencia obtusa were toxic in all three solvents. The acetone and ethanol extracts were more active, and therefore are more suitable for extraction of toxic substances. This revised version was published online in August 2006 with corrections to the Cover Date.