Important Source Of Compounds Research Articles

Monitoring the Phenolic and Terpenic Profile of Olives, Olive Oils and By-Products throughout the Production Process.

Olive oil is a food of great importance in the Mediterranean diet and culture. However, during its production, the olive oil industry generates a large amount of waste by-products that can be an important source of bioactive compounds, such as phenolic compounds and terpenes, revalorizing them in the context of the circular economy. Therefore, it is of great interest to study the distribution and abundance of these bioactive compounds in the different by-products. This research is a screening focused on phytochemical analysis, with particular emphasis on the identification and quantification of the phenolic and terpenic fractions. Both the main products of the olive industry (olives, olive paste and produced oil) and the by-products generated throughout the oil production process (leaf, "alpeorujo", liquid and solid residues generated during decanting commonly named "borras" and washing water) were analyzed. For this purpose, different optimized extraction procedures were performed for each matrix, followed by high-performance liquid chromatography coupled with electrospray time-of-flight mass spectrometry (HPLC-ESI-TOF/MS) analysis. Although no phenolic alcohols were quantified in the leaf and the presence of secoiridoids was low, this by-product was notable for its flavonoid (720 ± 20 µg/g) and terpene (5000 ± 300 µg/g) contents. "Alpeorujo" presented a complete profile of compounds of interest, being abundant in phenolic alcohols (900 ± 100 µg/g), secoiridoids (4500 ± 500 µg/g) and terpenes (1200 ± 100 µg/g), among others. On the other hand, while the solid residue of the borras was the most abundant in phenolic alcohols (3700 ± 200 µg/g) and secoiridoids (680 ± 20 µg/g), the liquid fraction of this waste was notable for its content of elenolic acid derivatives (1700 ± 100 µg/mL) and phenolic alcohols (3000 ± 300 µg/mL). Furthermore, to our knowledge, this is the first time that the terpene content of this by-product has been monitored, demonstrating that it is an important source of these compounds, especially maslinic acid (120 ± 20 µg/g). Finally, the phytochemical content in wash water was lower than expected, and only elenolic acid derivatives were detected (6 ± 1 µg/mL). The results highlighted the potential of the olive by-products as possible alternative sources of a wide variety of olive bioactive compounds for their revalorization into value-added products.

Exploring the Potential of Using Marine-Derived Ingredients: From the Extraction to Cutting-Edge Cosmetics.

The growing understanding and knowledge of the potential of marine species, as well as the application of "blue biotechnology" have been motivating new innovative solutions in cosmetics. It is widely noted that that marine species are important sources of compounds with several biological activities that are yet to be discovered. This review explores various biological properties of marine-derived molecules and briefly outlines the main extraction methods. Alongside these, it is well known the legislative and normative framework of cosmetics is increasingly being developed. In this research segment, there is a growing concern with sustainability. In this sense, "blue biotechnology", together with the use of invasive species or marine waste products to obtain new active ingredients, haven been emerging as innovative and sustainable solutions for the future's cosmetics industry. This review also examines the regulatory framework and focus on the recent advancements in "blue biotechnology" and its relevance to the sustainable development of innovative cosmetics.

Delving into the lifestyle of Sundarban Wetland resident, biofilm producing, halotolerant Salinicoccus roseus: a comparative genomics-based intervention

BackgroundMicrobial community played an essential role in ecosystem processes, be it mangrove wetland or other intertidal ecologies. Several enzymatic activities like hydrolases are effective ecological indicators of soil microbial function. So far, little is known on halophilic bacterial contribution and function on a genomic viewpoint of Indian Sundarban Wetland. Considering the above mentioned issues, the aims of this study was to understand the life style, metabolic functionalities and genomic features of the isolated bacterium, Salinicoccus roseus strain RF1H. A comparative genome-based study of S. roseus has not been reported yet. Henceforth, we have considered the inclusion of the intra-species genome comparison of S. roseus to gain insight into the high degree of variation in the genome of strain RF1H among others.ResultsSalinicoccus roseus strain RF1H is a pink-red pigmented, Gram-positive and non-motile cocci. The bacterium exhibited high salt tolerance (up to 15% NaCl), antibiotic resistance, biofilm formation and secretion of extracellular hydrolytic enzymes. The circular genome was approximately 2.62978 Mb in size, encoding 574 predicted genes with GC content 49.5%. Presence of genomic elements (prophages, transposable elements, CRISPR-Cas system) represented bacterial virulence and multidrug-resistance. Furthermore, genes associated with salt tolerance, temperature adaptation and DNA repair system were distributed in 17 genomic islands. Genes related to hydrocarbon degradation manifested metabolic capability of the bacterium for potential biotechnological applications. A comparative pangenome analysis revealed two-component response regulator, modified C4-dicarboxylate transport system and osmotic stress regulated ATP-binding proteins. Presence of genes encoding arginine decarboxylase (ADC) enzyme being involved in biofilm formation was reported from the genome. In silico study revealed the protein is thermostable and made up with ~ 415 amino acids, and hydrophilic in nature. Three motifs appeared to be evolutionary conserved in all Salinicoccus sequences.ConclusionThe first report of whole genome analysis of Salinicoccus roseus strain RF1H provided information of metabolic functionalities, biofilm formation, resistance mechanism and adaptation strategies to thrive in climate-change induced vulnerable spot like Sundarban. Comparative genome analysis highlighted the unique genome content that contributed the strain’s adaptability. The biomolecules produced during metabolism are important sources of compounds with potential beneficial applications in pharmaceuticals.

Methyl-4-hydroxy-2-(2-hydroxypropan-2-yl)-6-methyl-2,3-dihydrobenzofuran-5-carboxylate

Microorganisms are an important source of compounds that are pharmaceutically active, both as leads and as scaffolds for synthesis. Often, interesting chemistry is uncovered by exploring new biomes, of which the Chilean Atacama Desert is a prime example. This paper describes the isolation and structural characterisation, using HR-LCMS and 1D and 2D NMR, of a new compound belonging to a family of compounds called radstrictins. The compound was isolated from a fungus, that had itself been isolated from a soil sample from the Atacama Desert. The compound was tested against pathogenic strains associated with bovine mastitis, but was found to be devoid of antimicrobial activity.

Antitumor Effect of Açaí (Euterpe oleracea Mart.) Seed Extract in LNCaP Cells and in the Solid Ehrlich Carcinoma Model.

Euterpe oleracea (açaí) fruit has approximately 15% pulp, which is partly edible and commercialized, and 85% seeds. Although açaí seeds are rich in catechins-polyphenolic compounds with antioxidant, anti-inflammatory, and antitumor effects-almost 935,000 tons/year of seeds are discarded as industrial waste. This work evaluated the antitumor properties of E. oleracea in vitro and in vivo in a solid Ehrlich tumor in mice. The seed extract presented 86.26 ± 0.189 mg of catechin/g of extract. The palm and pulp extracts did not exhibit in vitro antitumor activity, while the fruit and seed extracts showed cytotoxic effects on the LNCaP prostate cancer cell line, inducing mitochondrial and nuclear alterations. Oral treatments were performed daily at 100, 200, and 400 mg/kg of E. oleracea seed extract. The tumor development and histology were evaluated, along with immunological and toxicological parameters. Treatment at 400 mg/kg reduced the tumor size, nuclear pleomorphism, and mitosis figures, increasing tumor necrosis. Treated groups showed cellularity of lymphoid organs comparable to the untreated group, suggesting less infiltration in the lymph node and spleen and preservation of the bone marrow. The highest doses reduced IL-6 and induced IFN-γ, suggesting antitumor and immunomodulatory effects. Thus, açaí seeds can be an important source of compounds with antitumor and immunoprotective properties.

Chemical Survey of Three Species of the Genus Rauhia Traub (Amaryllidaceae).

Plant biodiversity is an important source of compounds with medicinal properties. The alkaloid galanthamine, first isolated from Galanthus woronowii (Amaryllidaceae), is approved by the FDA for the palliative treatment of mild to moderate Alzheimer's disease due to its acetylcholinesterase (AChE) inhibitory activity. Obtaining this active pharmaceutical ingredient, still sourced on an industrial scale from the Amaryllidaceae species, is a challenge for pharmaceutical companies due to its low natural yield and the high cost of its synthesis. The aim of this work was to determine the alkaloid profile of three different Rauhia (Amaryllidaceae) species collected in Peru, and to assess the potential application of their extracts for the treatment of Alzheimer's disease. The alkaloids were identified by gas chromatography coupled to mass spectrometry (GC-MS), and the AChE inhibitory activity of the extracts was analyzed. Thirty compounds were quantified from the Rauhia species, the R. multiflora extract being the most interesting due to its high diversity of galanthamine-type structures. The R. multiflora extract was also the most active against AChE, with the half maximal inhibitory concentration (IC50) values of 0.17 ± 0.02 μg·mL-1 in comparison with the IC50 values of 0.53 ± 0.12 μg·mL-1 for galanthamine, used as a reference. Computational experiments were carried out on the activity of the galanthamine-type alkaloids identified in R. multiflora toward five different human AChE structures. The simulation of the molecules 3-O-acetylgalanthamine, 3-O-acetylsanguinine, narwedine, and lycoraminone on the 4EY6 crystal structure theoretically showed a higher inhibition of hAChE and different interactions with the active site compared to galanthamine. In conclusion, the results of this first alkaloid profiling of the Rauhia species indicate that R. multiflora is an important natural source of galanthamine-type structures and could be used as a model for the development of biotechnological tools necessary to advance the sustainable production of galanthamine.

Anti-proliferative and pro-apoptotic activity of glycosidic derivatives of lawsone in melanoma cancer cell

BackgroundMelanoma is a malignant cancer that affects melanocytes and is considered the most aggressive skin-type cancer. The prevalence for melanoma cancer for the last five year is about one million cases. The impact caused of this and other types of cancer, revel the importance of research into potential active compounds. The natural products are an important source of compounds with biological activity and research with natural products may enable the discovery of compounds with potential activity in tumor cells.MethodsThe Sulforhodamine B was used to determine cell density after treatment with lawsone derivatives. Apoptosis and necrosis were analyzed by flow cytometer. Morphological changes were observed by fluorescence using the Phalloidin/FITC and DAPI stains. The clonogenic and wound healing assays were used to analyze reduction of colonies formation and migratory capacity of melanoma cells, respectability.ResultsIn pharmacological screening, seven compounds derived from lawsone were considered to have high cytotoxic activity (GI > 75%). Three compounds were selected to assess the inhibitory concentration for 50% of cells (IC50), and the compound 9, that has IC50 5.3 μM in melanoma cells, was selected for further analyses in this cell line. The clonogenic assay showed that the compound is capable of reducing the formation of melanoma colonies at 10.6 μM concentration. The compound induced apoptotic morphological changes in melanoma cells and increased by 50% the cells dying from apoptosis. Also, this compound reduced the migratory capacity of melanoma cells.ConclusionsThe results of this study showed that the evaluated lawsone derivatives have potential activity on tumor cells. The compound 9 is capable of inducing cell death by apoptosis in melanoma cells (B16F10).

Whole Blood Transcriptome Profiling Reveals Positive Effects of Olive Leaves-Supplemented Diet on Cholesterol in Goats.

Simple SummaryThe aim of this study was to analyze the whole blood transcriptome of lactating goats fed a dietary supplementation with 10% olive leaves, one of the main by-products deriving from the olive oil chain supply. This evaluation was effective in identifying the differential regulation of the gene coding for apolipoprotein B mRNA editing enzyme catalytic subunit 2 (APOBEC2), which showed downregulated in goats that received the dietary supplementation. Taking into account the strong association between plasma apoB and low-density lipoprotein, an evaluation was performed of both blood and milk cholesterol. The obtained data demonstrated a significant lower concentration of circulating cholesterol and cholesterol released into the milk through the mammary gland, demonstrating positive effects of olive leaves feeding on animal welfare and potential health benefits for consumers.Agro-industrial by-products represent an important source of compounds credited with high biotechnological potential. In the last decade, considerable interest has developed toward the use of these matrices as dietary supplements in the zootechnical field, paying particular attention to the qualitative aspects associated with animal products. However, less is known about the effect of these matrices on gene expression and thus on animal metabolism. Therefore, the aim of this study was to analyze the whole blood transcriptome of lactating goats fed a dietary supplementation with 10% olive leaves (OL), one of the main by-products deriving from the olive oil chain supply. By applying a false discovery rate (FDR) < 0.05 and a Log2 Fold change (Log2Fc) lower than −0.5 or higher than +0.5, it was possible to identify the differential regulation of gene coding for the apolipoprotein B (apoB) mRNA editing enzyme catalytic subunit 2 (APOBEC2), which showed downregulation in goats that received the dietary supplementation. An evaluation of both blood and milk cholesterol was performed, taking into account the strong association between plasma apoB and low-density lipoprotein (LDL). Results showed significantly lower concentrations of circulating cholesterol and cholesterol released into the milk through the mammary gland, demonstrating positive effects of OL feeding on animal welfare and potential health benefits for consumers.

Resveratrol effects in bladder cancer: A mini review.

Bladder cancer has a high incidence worldwide and is the most common genitourinary cancer. The treatment of bladder cancer involves surgery and chemotherapy; however high failure rates and toxicity are observed. In this context, the search of new drugs aiming a more effective treatment is extremely necessary. Natural products are an important source of compounds with antiproliferative effects. Resveratrol is a naturally occurring plant polyphenol whose anticancer activity has been demonstrated in different types of cancer. This review summarizes the in vitro and in vivo studies using models of bladder cancer treated with resveratrol and discusses its different mechanisms of action.

Antimicrobial screening and hemolytic activity of products obtained from Piper montealegreanum Yuncker and effect in vitro on growth of Staphylococcus aureus

This study aimed to determine spectrum of antimicrobial activity of crude ethanolic extract (CEE), chloroform (CHCl3) and ethyl acetate (EtOAc) fractions, to determine influence of CHCl3 fraction on Staphylococcus aureus growth and hemolytic activity. Antimicrobial screening of CEE, CHCl3 and EtOAc fractions was carried out using broth microdilution technique against standard strains: Staphyloccocus aureus ATCC25923, Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853 and Candida albicans ATCC76645 to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Time kill curves were performed to determine influence of CHCl3 fraction on MIC and ½ MIC concentrations on S. aureus growth. Hemolytic activity of CHCl3 was performed in human erythrocytes to report the cytotoxic effect. CHCl3 fraction showed activity against S. aureus with MIC=1024 µg mL-1 and MBC=2048 µg mL-1. This fraction did not show activity against other tested strains, as well as the CEE and EtOAc fraction. Time kill curve of S. aureus treated with CHCl3 fraction showed that at MIC this fraction has bacteriostatic activity, which was not observed with the ½ MIC. Hemolytic activity demonstrated that when CHCl3 fraction in MIC does not present membrane damage of erythrocytes, since it did not cause hemolysis. Studies should be conducted to evaluate the activity of CHCl3 fraction against S. aureus with different antimicrobial resistance profiles, in addition to evaluating the potential for resistance reversion by in vitro combination studies. The study demonstrated that the species P. montealegreanum can be an important source of compounds of importance for combating microorganisms of clinical importance.

Micropropagation and Production of Somatic Seeds for Short-Term Storage of the Endangered Species Eryngium alpinum L.

Eryngium alpinum L. is a high-value herb and a source of important compounds that include phenolics, triterpenoid saponins, and essential oils. The present report indicates successful micropropagation of this species. In our study, medium supplemented with BAP 2.0 mg/L, IAA 1.0 mg/L, and GA3 1.0 mg/L was found to be the most suitable for long-term culture and for effective proliferation, irrespective of the passage number. Roots induction, without basal callus formation, was observed when individual microshoots were placed on Murashige & Skoog medium augmented with auxin, and formation was the most advantageous in the presence of NAA alone or when combined with IAA or IBA. The encapsulated propagules were tested for their capability to endure different storage periods under low temperature. Therefore, we developed an efficient method for synseeds production by encapsulation of axillary buds in the sodium alginate matrix, storage for 2, 4, and 6 months, as well as the regeneration process. The maximum regeneration rate of 74% ± 2.72% was observed for axillary buds encapsulated in 4% sodium–alginate complexed with 300 mM calcium chloride after 2 months of storage at low temperature. This is the first report on E. alpinum micropropagation and somatic seeds production.

Toxicological Evaluation of Some Essential Oils Obtained from Selected Romania Lamiaceae Species in Complex with Hydroxypropyl - gamma-cyclodextrin

Medicinal plants are highly investigated due to their multiple effects in human health. In the last two decades, plants belonging to Lamiaceae family have emerged as an important source of compounds with beneficial effects in various pathologies. Many species of the Lamiaceae family have a high volatile oil content which can be found in different parts of the plant. Some representative examples include Lavandula spp. Salvia spp. and Mentha spp. which are species with essential oils studied for antioxidant, antimicrobial and antitumor effects. The aim of this study was to evaluate the effect of six essential oils at skin level before and after encapsulation in hydroxypropyl-gamma-cyclodextrins. Results indicated that regardless of the tested form, the samples did not display an irritating or toxic effect at skin level, suggesting that the essential oils can be used in different formulations for topical application.

Toxicological Evaluation of Some Essential Oils Obtained from Selected Romania Lamiaceae Species in Complex with Hydroxypropyl - gamma-cyclodextrin

Medicinal plants are highly investigated due to their multiple effects in human health. In the last two decades, plants belonging to Lamiaceae family have emerged as an important source of compounds with beneficial effects in various pathologies. Many species of the Lamiaceae family have a high volatile oil content which can be found in different parts of the plant. Some representative examples include Lavandula spp. Salvia spp. and Mentha spp. which are species with essential oils studied for antioxidant, antimicrobial and antitumor effects. The aim of this study was to evaluate the effect of six essential oils at skin level before and after encapsulation in hydroxypropyl-gamma-cyclodextrins. Results indicated that regardless of the tested form, the samples did not display an irritating or toxic effect at skin level, suggesting that the essential oils can be used in different formulations for topical application. Keywords: essential oils, Lamiaceae, hydroxypropyl-gamma-cyclodextrins, mexametry, corneometry, tewametry

Antioxidant capacity, bioactive compounds in coffee pulp and implementation in the production of infusions.

The main by-product of the coffee production chain is pulp; if it is not properly disposed of, it represents a serious environmental problem. Some studies suggest that this pulp can be used as a source of important compounds. The aim of this study was to evaluate the content of bioactive compounds present in coffee pulps and also to prepare a functional drink-type infusion to propose an alternative use of this by-product. In coffee pulps (Coffea arabica, var. Colombia and Caturra), the effect of the tem- perature and the extraction type over the content of total polyphenols, total flavonoids, condensed tannins and phenolic acids were determined. Moreover, the antioxidant activity by ABTS, ORAC and FRAP methodolo- gies. With the best pulp, an infusion-type hot drink was prepared at 80&deg;C. Finally, sensory assessment was performed. The best conditions to perform the metabolite extraction were room temperature and HCl 1%. The highest trapping capacity of the cationic radical ABTS+* was 24 782.93 &mu;mol Trolox Equivalent per 100 g of pulp, ORAC 57 087.82 &mu;mol Trolox Equivalent per 100 g of pulp and FRAP 806.93 mg of ascorbic acid equivalent per 100 g of pulp. For the infusion preparation, two drying methods were used &ndash; stove and lyophi- lization, and overall the best results correspond to the infusions prepared with the lyophilized plant material. This material also had good overall scores in the sensory test (3.51 to 4.04 on a scale of 1 to 5) been the taste most appreciated by the panelists. The bioactive compound concentration and the antioxidant activity of the coffee pulp suggest that waste can be used as a raw material for the preparation of functional foods, because the values found are similar or greater than those found in other drinks and fruits consumed commercially.

Studies on genetic variability of Tinospora cordifolia collected from different agroclimatic zones of Haryana using RAPD markers

Medicinal plants are an important source of compounds for the pharmaceuticals and other industries and traditional medicine. Tinospora cordifolia, commonly known as giloe, is one of the important medicinal climbers which belongs to the family Menispermaceae. Studies were undertaken for identification and genetic variation within six accessions of T. cordifolia through random amplified polymorphic DNA (RAPD) markers. Analysis was made using 12 primers. Out of them, eight primers showed amplification and were selected for genetic relationship within six accessions. A total of 81 bands were produced of size 100 to 950 bp with an average of 6.75 bands for each primer, of which 80 bands were polymorphic. The polymorphism percentage was 98.56 and Polymorphic Index Content (PIC) value ranged from 0.722 to 0.992. The genetic similarity index was calculated using Jaccard's similarity coefficient which ranged from 0.4225 to 0.7000. The dendrogram was constructed using similarity matrix based on UPGMA method, which resulted into two main clusters. The two genotypes TC2 and TC3 were closely related accessions, whereas TC4 and TC6 were distantly related accessions. In conclusion, clustering of majority of accessions in one group reflected the narrow genetic structure of Tinospora populations in the region and the RAPD technique is highly popular and reveals relatively high levels of polymorphism.

An aqueous extract of Nomura’s jellyfish ameliorates inflammatory responses in lipopolysaccharide-stimulated RAW264.7 cells and a zebrafish model of inflammation

The recent mass emergence of Nomura’s jellyfish (Nemopilema nomurai) has caused much economic and environmental damage. However, there is no innovative strategy to dispose of or utilize these jellyfish. Some reports suggest that the jellyfish may be bioactive resources and a source of important compounds with antibacterial activity. Here, we examined the effect of an aqueous extract of Nomura’s jellyfish (AENJ) on lipopolysaccharide (LPS)-stimulated Raw 264.7 macrophages and a zebrafish model of inflammation and analyzed the underlying molecular mechanisms.AENJ downregulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA levels in LPS-stimulated Raw 264.7 macrophages, with no apparent cytotoxic effects. However, AENJ had no effect on expression of other inflammation-related genes such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and MCP-1. Furthermore, AENJ reduced expression of nerve injury-induced protein 1 (Ninj1), which is an important adhesion molecule, thereby reducing cell adhesion to the extracellular matrix (ECM) in vitro. The inhibitory effect of AENJ on leukocytes was confirmed in LPS-microinjected zebrafish larvae; AENJ reduced the number of the infiltrate accumulating at the site of inflammation. In addition, AENJ suppressed the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 in LPS-stimulated Raw 264.7 cells. Finally, AENJ blocked nuclear translocation of nuclear factor kappa B (NF-κB), a key transcription factor for inflammatory responses, in Raw 264.7 cells in a dose-dependent manner.Collectively, the data suggest that AENJ inhibits expression of COX and iNOS by blocking NF-κB signaling pathways and suppresses the activity of macrophages by downregulating Ninj1 and MMPs. Therefore, AENJ may be a useful preventive neutraceutical, or therapeutic agent against inflammatory disorders.

English

Fil: Martinez, Maria Julia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Quimica; Argentina

Adding value to agri-food residues by means of supercritical technology

The demand for resources to supply the world's energy needs has been increasing day by day; agricultural processing wastes and residues generated by the industrial sector could be transformed into energy, mitigating environmental impact. Rising concern about environmental issues has been increasing, which, in turn, presses governments and companies to develop policies and solutions to solve these problems. In this context, the industrial symbiosis aims to reach sustainability by closing productive cycles, where the residues from an industry are the raw material for others. Agri-food residues are important sources of compounds with commercial interest that could be recovered both to decrease the volume of residues generated, and also to improve the economic viability of processes, by producing added value products. For this purpose, several applications of the supercritical technology to add value to agri-food residues through both extraction of high value-added compounds and hydrolysis of lignocellulosic biomass to produce fermentable sugars are presented.

Marine Natural Products As Anticancer Agents

The marine environment remain an important source of compounds that possess anticancer activities and some other demonstrated activities likeantitumor, immunomodulation, anti-inflammatory, allergy, analgesia. The purpose of this article is to present different different compounds of anticancer agent which are derived from marine sources and present their structured part and different mode of action of all these different drugs. The drugs which are included in this article, some of them are in pre-clinical trials or clinical development and some are available in market such as Cytarabine and ET-743.

Inhibitory activity of an extract from a marine bacterium Halomonas sp. HSB07 against the red-tide microalga Gymnodinium sp. (Pyrrophyta)

In recent years, red tides occurred frequently in coastal areas worldwide. Various methods based on the use of clay, copper sulfate, and bacteria have been successful in controlling red tides to some extent. As a new defensive agent, marine microorganisms are important sources of compounds with potent inhibitory bioactivities against red-tide microalgae, such as Gymnodinium sp. (Pyrrophyta). In this study, we isolated a marine bacterium, HSB07, from seawater collected from Hongsha Bay, Sanya, South China Sea. Based on its 16S rRNA gene sequence and biochemical characteristics, the isolated strain HSB07 was identified as a member of the genus Halomonas. A crude ethyl acetate extract of strain HSB07 showed moderate inhibition activity against Gymnodinium sp. in a bioactive prescreening experiment. The extract was further separated into fractions A, B, and C by silica gel column chromatography. Fractions B and C showed strong inhibition activities against Gymnodinium. This is the first report of inhibitory activity of secondary metabolites of a Halomonas bacterium against a red-tide-causing microalga.