Adsorption of Cationic Dyes on a Magnetic 3D Spongin Scaffold with Nano-Sized Fe3O4 Cores

The renewable, proteinaceous, marine biopolymer spongin is yet the focus of modern research. The preparation of a magnetic three-dimensional (3D) spongin scaffold with nano-sized Fe₃O₄ cores is reported here for the first time. The formation of this magnetic spongin–Fe₃O₄ composite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA) (TGA-DTA), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), and zeta potential analyses. Field emission scanning electron microscopy (FE-SEM) confirmed the formation of well-dispersed spherical nanoparticles tightly bound to the spongin scaffold. The magnetic spongin–Fe₃O₄ composite showed significant removal efficiency for two cationic dyes (i.e., crystal violet (CV) and methylene blue (MB)). Adsorption experiments revealed that the prepared material is a fast, high-capacity (77 mg/g), yet selective adsorbent for MB. This behavior was attributed to the creation of strong electrostatic interactions between the spongin–Fe₃O₄ and MB or CV, which was reflected by adsorption mechanism evaluations. The adsorption of MB and CV was found to be a function of pH, with maximum removal performance being observed over a wide pH range (pH = 5.5–11). In this work, we combined Fe₃O₄ nanoparticles and spongin scaffold properties into one unique composite, named magnetic spongin scaffold, in our attempt to create a sustainable absorbent for organic wastewater treatment. The appropriative mechanism of adsorption of the cationic dyes on a magnetic 3D spongin scaffold is proposed. Removal of organic dyes and other contaminants is essential to ensure healthy water and prevent various diseases. On the other hand, in many cases, dyes are used as models to demonstrate the adsorption properties of nanostructures. Due to the good absorption properties of magnetic spongin, it can be proposed as a green and uncomplicated adsorbent for the removal of different organic contaminants and, furthermore, as a carrier in drug delivery applications.     

Chitosan-Alginate Biocomposite Containing Fucoidan for Bone Tissue Engineering

Over the last few years, significant research has been conducted in the construction of artificial bone scaffolds. In the present study, different types of polymer scaffolds, such as chitosan-alginate (Chi-Alg) and chitosan-alginate with fucoidan (Chi-Alg-fucoidan), were developed by a freeze-drying method, and each was characterized as a bone graft substitute. The porosity, water uptake and retention ability of the prepared scaffolds showed similar efficacy. The pore size of the Chi-Alg and Chi-Alg-fucoidan scaffolds were measured from scanning electron microscopy and found to be 62–490 and 56–437 µm, respectively. In vitro studies using the MG-63 cell line revealed profound cytocompatibility, increased cell proliferation and enhanced alkaline phosphatase secretion in the Chi-Alg-fucoidan scaffold compared to the Chi-Alg scaffold. Further, protein adsorption and mineralization were about two times greater in the Chi-Alg-fucoidan scaffold than the Chi-Alg scaffold. Hence, we suggest that Chi-Alg-fucoidan will be a promising biomaterial for bone tissue regeneration.     

Tuning the properties of PVDF or PVDF-HFP fibrous materials decorated with ZnO nanoparticles by applying electrospinning alone or in conjunction with electrospraying

Novel composite nanofibrous materials of poly(vinylidene fluoride) (PVDF) or poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP) and ZnO nanoparticles were prepared by conjunction of electrospinning and electrospraying techniques. Simultaneous electrospinning of concentrated solution of PVDF or PVDF-HFP and electrospraying of suspension of ZnO in diluted PVDF or PVDF-HFP solution enable the preparation of materials consisting of fibers on which ZnO was deposited on the fibers’ surface (design type “on”). These fibrous materials were compared with materials consisting of PVDF or PVDF-HFP fibers in which ZnO was incorporated in the fibers (design type “in”) and which were obtained by one-pot electrospinning of a suspension of ZnO nanoparticles in concentrated PVDF or PVDF-HFP solution. The fiber morphology and the presence of ZnO “in” or “on” the fibers were observed by scanning electron microscopy (SEM) and by transmission electron microscopy (TEM). The effect of the used technique on the type, size and shape of the obtained structures was discussed. The fibrous mats were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), contact angle measurements and mechanical tests as well. It was found that the decoration of fibers with ZnO resulted in increase of their thermal stability and hydrophobicity. The microbiological tests showed that the materials of design type “on” possessed strong antibacterial activity against the pathogenic microorganism Staphylococcus aureus. The results suggest that, due to their antibacterial activity, the obtained composite materials are suitable for wound dressing applications.     

Fabrication and Characterization of Nanocomposite Hydrogel Based on Alginate/Nano-Hydroxyapatite Loaded with Linum usitatissimum Extract as a Bone Tissue Engineering Scaffold

In the current paper, we fabricated, characterized, and applied nanocomposite hydrogel based on alginate (Alg) and nano-hydroxyapatite (nHA) loaded with phenolic purified extracts from the aerial part of Linum usitatissimum (LOH) as the bone tissue engineering scaffold. nHA was synthesized based on the wet chemical technique/precipitation reaction and incorporated into Alg hydrogel as the filler via physical cross-linking. The characterizations (SEM, DLS, and Zeta potential) revealed that the synthesized nHA possess a plate-like shape with nanometric dimensions. The fabricated nanocomposite has a porous architecture with interconnected pores. The average pore size was in the range of 100–200 µm and the porosity range of 80–90%. The LOH release measurement showed that about 90% of the loaded drug was released within 12 h followed by a sustained release over 48 h. The in vitro assessments showed that the nanocomposite possesses significant antioxidant activity promoting bone regeneration. The hemolysis induction measurement showed that the nanocomposites were hemocompatible with negligible hemolysis induction. The cell viability/proliferation confirmed the biocompatibility of the nanocomposites, which induced proliferative effects in a dose-dependent manner. This study revealed the fabricated nanocomposites are bioactive and osteoactive applicable for bone tissue engineering applications.     

Preparation and use of amine-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) fibers for removal of chromium(VI) from aqueous solution

Poly(ethylene terephthalate) (PET) fibers were grafted with glycidyl methacrylate (GMA) using benzoyl peroxide as initiator. 1,6-diaminohexane (HMDA) was then covalently attached to this GMA grafted PET fibers. Variations of time, temperature, initiator and monomer concentrations were investigated. HMDA-GMA-g-PET fibers were used as a new sorbent for removal of Cr(VI) ions from aqueous solutions through batch adsorption method. Effects of various parameters such as pH, treatment time, and initial ions concentration on the adsorption amount of ions onto reactive fibers were investigated. The adsorption rates of Cr(VI) ions were much higher on the HMDA-GMA-g-PET fiber than on GMA-g-PET and ungrafted PET fiber. Within 60 min, at pH 3, Cr(VI) was removed by 98 % while the initial concentration of ions was at 25 mg/l and by 94 % at 400 mg/l. The Cr(VI) ions adsorbed were easily desorbed by treating with 1M KOH within 10 min.     

Electrospun grape seed polyphenols/gelatin composite fibers contained silver nanoparticles as biomaterials

GSP/gelatin composite nanofiber membranes containing silver nanoparticles were successfully fabricated as a novel biomaterial by electrospinning. The silver nanoparticles (AgNPs) were synthesized with the grape seed polyphenols (GSP) as reducing agent in aqueous solution of gelatin, and then the GSP/gelatin/AgNPs mixed solution was electrospun into nanofibers at 55 °C. The scanning electron microscopy (SEM) confirmed that the composite fibers were uniform and the average fiber diameter ranged between 150 nm and 230 nm with an increase in applied potentials from 14 kV to 22 kV. And the transmission electron microscopy (TEM) showed that silver nanoparticles distributed individually in the fibers with the average particle size of about 11 nm. Furthermore, the ultraviolet visible spectrophotometer (UV-vis spectroscopy) test demonstrated that all of Ag⁺ converted to Ag⁰ when the concentration of gelatin was 24 wt% and the mass ratio of GSP to AgNO₃ was about 5:2. The antibacterial activities of the fiber membranes against E.coli and S.aureus were measured via a shake flank test and demonstrated good performance after the importation of silver nanopaticles. Cytotoxicity testing also revealed that fiber membranes contained silver nanoparticles had no cyto-toxic. All the results indicated that the GSP was effective for the formation and stabilization of silver nanoparticles in composite nanofibers mats which had the potential for applications in antimicrobial tissue engineering and wound dressing.     

Preparation and antibacterial property of the mulberry based textiles

The mulberry based textile products were prepared by means of degumming, dyeing, spinning and weaving using mulberry bark as raw materials. The structure of the mulberry based textiles was characterized by scanning electron microscope (SEM). The antibacterial property of the mulberry fibers was evaluated by means of antibacterial testing, and the antibacterial composition in the mulberry based textiles was investigated by FTIR and ¹³C-NMR. The results show that the mulberry based fibers, dyed fibers, yarns and fabrics with high quality can be prepared successfully by the above processes. The mulberry based textiles have excellent antibacterial property. The inhibitory rate of raw mulberry bark on Escherichia coli and Staphylococcus aureus is (67.2±3.1)% and (53.8±4.6)% respectively, and the inhibitory rate of mulberry fiber on Escherichia coli and Staphylococcus aureus is both above 80%. The inhibitory rate of the mulberry/cotton blended yarn on Escherichia coli and Staphylococcus aureus ranges from (51.7±5.1)% to (72.4±4.1)%, which has similar inhibitory rate with the mulberry/cotton blended fabric. The results of Fourier Transform-Infrared (FTIR) and ¹³C-nuclear magnetic resonance (¹³C-NMR) show that the typical functional group (hydroxyl, carbonyl, double bond and epoxy bond) exist in the composition of the mulberry fiber, which indicates that the flavones and phenolic compounds including in the mulberry fiber.     

Preparation and BSA Adsorption Behavior of Chitosan-arginine Based Nanofiber Membranes

In this work, an affinity nanofiber membrane was successfully prepared by solution blowing of arginine-modified chitosan (CS-Arg) for bovine serum albumin (BSA) adsorption. CS-Arg was firstly synthesized by coupling L-arginine onto chitosan backbone. Then, CS-Arg nanofiber membranes (CANFs) were fabricated using solution blowing process with Polylactide (PLA) as assistant polymer. The results showed that CANFs effectively adsorbed BSA, and the adsorption capacities were influenced by the degrees of substitution (DS) of arginine in CS, pH value, contact time, and initial protein concentration. The highest adsorption capacity of 445.19 mg/g was achieved uvnder the following conditions: DS of 43.7 %, pH of 7.14, and initial concentration of 3.0 mg/ml. BSA adsorbed on the CANFs membrane conformed to Langmuir model, and the adsorption rate was consistent with the second-order kinetics model. This work implies that an arginine-modified chitosan nanofiber-based novel biomaterial has a potential application in adsorption of BSA.     

Six New Diterpene Glycosides from the Soft Coral Lemnalia bournei

A chemical study on the extracts of soft coral Lemnalia bournei resulted in the isolation and identification of six new bicyclic diterpene glycosides including three new lemnaboursides E–G (1–3), and three new lemnadiolboursides A–C (4–6), along with three known lemnaboursides (7–9). Their structures were elucidated by detailed spectroscopic analysis, ECD analysis, chemical methods, and comparison with the literature data. Lemnadiolboursides A–C (4–6) contained a lemnal-1(10)-ene-7,12-diol moiety compared with the lemnaboursides. All these compounds were evaluated for antibacterial activity; cell growth inhibition of A549, Hela, HepG2, and CCRF-CEM cancer cell lines; and inhibition of LPS-induced NO production in RAW264.7 macrophages. The results indicated that compounds 1, 2, and 4–6 exhibited antibacterial activity against Staphylococcus aureus and Bacillus subtilis (MIC 4–16 μg/mL); compounds 1–9 displayed low cytotoxicity on the CCRF-CEM cell lines (IC₅₀ 10.44–27.40 µM); and compounds 1, 2, and 5 showed weak inhibition against LPS-induced NO production (IC₅₀ 21.56–28.06 μM).     

Macro-micro structure,antibacterial activity,and physico-mechanical properties of the mulberry bast fibers

In this paper, the mulberry fibers were successfully obtained by a new pretreatment named alkali-assisted microwave plus biological enzymatic technique (AMBET). The morphology, microstructure, physico-mechanical and antibacterial properties of the mulberry bast fibers were investigated by means of scanning electron microscope (SEM), Fourier Transform-Infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), instron tensile tester and antibacterial testing. The results showed that impurities of the bast fibers could be removed by AMBET treatment. AMBET treated mulberry fiber was even, smooth and fine, and typical cellulose I in the mulberry fibers was confirmed by FTIR and XRD analysis. The crystallinity of the AMBET treated fibers was higher than that of the raw mulberry and chemical treated mulberry fibers. Thermal analysis indicated that the mulberry fibers had a good thermal stability. Moreover, the AMBET treated mulberry fibers showed excellent antimicrobial activities against S.aureus. The physical properties of the mulberry fibers indicated the AMBET treated mulberry fibers were ideal candidates for new textile materials.     

A Coralline Algal-Associated Bacterium,Pseudoalteromonas Strain J010, Yields Five New Korormicins and a Bromopyrrole

The ethanol extract of Pseudoalteromonas strain J010, isolated from the surface of the crustose coralline alga Neogoniolithon fosliei, yielded thirteen natural products. These included a new bromopyrrole, 4′-((3,4,5-tribromo-1H-pyrrol-2-yl)methyl)phenol (1) and five new korormicins G–K (2–6). Also isolated was the known inducer of coral larval metamorphosis, tetrabromopyrrole (TBP), five known korormicins (A–E, previously named 1, 1a–c and 3) and bromoalterochromide A (BAC-A). Structures of the new compounds were elucidated through interpretation of spectra obtained after extensive NMR and MS investigations and comparison with literature values. The antibacterial, antifungal and antiprotozoal potential of 1–6, TBP and BAC-A was assessed. Compounds 1–6 showed antibacterial activity while BAC-A exhibited antiprotozoal properties against Tetrahymena pyriformis. TBP was found to have broad-spectrum activity against all bacteria, the protozoan and the fungus Candida albicans.     

Identification and Heterologous Expression of the Kendomycin B Biosynthetic Gene Cluster from Verrucosispora sp. SCSIO 07399

Verrucosispora sp. SCSIO 07399, a rare marine-derived actinomycete, produces a set of ansamycin-like polyketides kendomycin B–D (1–3) which possess potent antibacterial activities and moderate tumor cytotoxicity. Structurally, kendomycin B–D contain a unique aliphatic macrocyclic ansa scaffold in which the highly substituted pyran ring is connected to the quinone moiety. In this work, a type I/type III polyketide synthase (PKS) hybrid biosynthetic gene cluster coding for assembly of kendomycin B (kmy), and covering 33 open reading frames, was identified from Verrucosispora sp. SCSIO 07399. The kmy cluster was found to be essential for kendomycin B biosynthesis as verified by gene disruption and heterologous expression. Correspondingly, a biosynthetic pathway was proposed based on bioinformatics, cluster alignments, and previous research. Additionally, the role of type III PKS for generating the precursor unit 3,5-dihydroxybenzoic acid (3,5-DHBA) was demonstrated by chemical complementation, and type I PKS executed the polyketide chain elongation. The kmy cluster was found to contain a positive regulatory gene kmy4 whose regulatory effect was identified using real-time quantitative PCR (RT-qPCR). These advances shed important new insights into kendomycin B biosynthesis and help to set the foundation for further research aimed at understanding and exploiting the carbacylic ansa scaffold.     

New Furan and Cyclopentenone Derivatives from the Sponge-Associated Fungus Hypocrea Koningii PF04

Two new furan derivatives, hypofurans A and B (1 and 2), and three new cyclopentenone derivatives, hypocrenones A–C (3–5), along with seven known compounds (6–12), were isolated from a marine fungus Hypocrea koningii PF04 associated with the sponge Phakellia fusca. Among them, compounds 10 and 11 were obtained for the first time as natural products. The planar structures of compounds 1–5 were elucidated by analysis of their spectroscopic data. Meanwhile, the absolute configuration of 1 was determined as 2R,3R by the comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. All the isolates were evaluated for their antibacterial and antioxidant activity. Compounds 1, 10, and 12 all showed modest antibacterial activity against Staphylococcus aureus ATCC25923 (MIC, 32 μg/mL). In addition, compounds 1, 10 and 11 exhibited moderate DPPH radical scavenging capacity with IC₅₀ values of 27.4, 16.8, and 61.7 µg/mL, respectively.     

Preparation of Cu-BTC/PVA Fibers with Antibacterial Applications

In this study, a metal-organic framework (MOF)/polymer electrospun fiber was prepared. The MOF, copper-1,3,5- benzenetricarboxylate (Cu-BTC), was synthesized using a sonochemical method at 25 °C, with a 1:1:1 mixture of dimethylformamide, ethanol, and deionized water as solvent. The sonication time was shown to have a pronounced effect on the morphology and structure of the Cu-BTC. A square pyramid shape with sides of 100 nm was obtained after 2 h of sonication. Extending the sonication time provided a lower amount of unknown phase and produced a uniform Cu-BTC framework. The Cu-BTC-modified PVA fibers were then fabricated by electrospinning. The effect of the Cu-BTC and PVA concentration was investigated at 25 kV, a flow rate of 10 μl/min, and a working distance of 150 mm. FTIR spectra and FESEM images showed good dispersion of the Cu-BTC on the PVA fiber. The as-prepared Cu-BTC-modified PVA fibers exhibited excellent antibacterial effectiveness against S. aureus.     

Adsorption of Graphene Oxide onto Synthetic Fibers: Experimental Conditions

Comparative studies on the adsorption capacity of two synthetic fibers, polyamide (PA 66) and polyester (PET) pre-treated with N-cetylpyridinium chloride (PET-NCPCl), towards graphene oxide (GO) have been carried out. The fiber samples were characterized by scanning electron microscopy (FE-SEM) and Raman spectroscopy. The results of adsorption isotherms, kinetics, and zeta potential determinations as a function of the GO concentration, pH, and temperature show that at a low pH of 2.5 and a high temperature of 323 K, almost 99 % of the 75 mg/l GO solution is adsorbed onto PA 66 and 70 % onto the PET-NCPCl fibers. The interaction should be first attributed to electrostatic forces, also the adsorption data exhibited a good fit to the Freundlich isotherm model and the free energy value of 10 kJ/mol was in the range of physical adsorption, which could suggest that the interaction is driven mainly by physical forces. Due to the increasing development of wastewater treatments based on the GO reactivity with metals and cationic contaminants, synthetic fibers coated with GO could be considered an adsorbent for environmental applications.     

Antimicrobial and Antibiofilm Activities of the Fungal Metabolites Isolated from the Marine Endophytes Epicoccum nigrum M13 and Alternaria alternata 13A

Epicotripeptin (1), a new cyclic tripeptide along with four known cyclic dipeptides (2–5) and one acetamide derivative (6) were isolated from seagrass-associated endophytic fungus Epicoccum nigrum M13 recovered from the Red Sea. Additionally, two new compounds, cyclodidepsipeptide phragamide A (7) and trioxobutanamide derivative phragamide B (8), together with eight known compounds (9–16), were isolated from plant-derived endophyte Alternaria alternata 13A collected from a saline lake of Wadi El Natrun depression in the Sahara Desert. The structures of the isolated compounds were determined based on the 1D and 2D NMR spectroscopic data, HRESIMS data, and a comparison with the reported literature. The absolute configurations of 1 and 7 were established by advanced Marfey’s and Mosher’s ester analyses. The antimicrobial screening indicated that seven of the tested compounds exhibited considerable (MIC range of 2.5–5 µg/mL) to moderate (10–20 µg/mL) antibacterial effect against the tested Gram-positive strains and moderate to weak (10–30 µg/mL) antibacterial effect against Gram-negative strains. Most of the compounds exhibited weak or no activity against the tested Gram-negative strains. On the other hand, four of the tested compounds showed considerable antibiofilm effects against biofilm forming Gram-positive and Gram-negative strains.     

Water-resistant Lignin/Poly(vinyl alcohol) Blend Fibers for Removal of Hexavalent Chromium

Lignin is the second most abundant renewable biomass-derived natural resource that has been used to replace traditional petrochemical-based materials. However, fabricating the lignin component into the various forms required for practical application is still challenging. In this work, we fabricated water-resistant lignin/poly(vinyl alcohol) (PVA) blend fibers by wet spinning and glutaraldehyde crosslinking methods. The effect of the lignin/PVA blend ratio and glutaraldehyde crosslinking process on the physicochemical properties of wet-spun lignin/PVA blend fibers were studied using maximum draw ratios, hydrolytic degradation profiles, and mechanical properties. Furthermore, the hexavalent chromium [Cr(VI)] removal behavior of lignin/PVA blend fibers was investigated according to the effect of pH, initial Cr(VI) concentration, and contact time. The wet-spun lignin/PVA blend fiber achieved excellent water stability through glutaraldehyde crosslinking and exhibited notable Cr(VI) adsorption capacity (350.87 mg/g) and good regeneration ability. These findings demonstrate that glutaraldehyde-crosslinked lignin/PVA blend fibers could be promising adsorbents for the remediation of heavy metal species containing textile wastewater.     

Preparation,Characterization and Properties of High-salt-tolerance Sodium Alginate/Krill Protein Composite Fibers

Sodium alginate (SA) and krill protein (AKP) were blended to obtain composite solution, and functional SA/AKP composite fibers were prepared via wet spinning. To further improve the salt tolerance, SA/AKP composite fibers were modified with copper sulfate aqueous solution as secondary coagulation bath because of the strong adsorption to copper ions. The CSA/AKP composite fibers with high salt tolerance have been successfully prepared. The intermolecular interaction of SA/AKP composite system and the two-order structure of protein in the composite system were characterized by Fourier transform infrared spectroscopy (FT-IR). Besides, the crystallinity, morphology, mechanical properties, salt tolerance and water resistance and thermal stability of SA/AKP composites were investigated respectively. The results showed that the adsorption rate and the adsorption capacity of the composite solution to copper ion were significantly higher than those to calcium ion. Under the effect of secondary solidification by copper sulfate, the β-sheet chain of the composite fibers increased from 41.48 % to 49.21 %, the intramolecular hydrogen bond increased from 38.18 % to 44.26 %, the intermolecular hydrogen bond decreased from 59.84 % to 54.70 % and free hydroxyl slightly decreased. The water resistance of the modified composite fibers was improved by about 22 %; when the swelling time was 25 min, the salt resistance increased by about 150 %; the number of grooves on the surface of the composite fibers obviously increased, and the grooves on the surface of CSA/AKP composite fibers and the fiber section structure were much denser; Meanwhile, copper sulfate had some influence on the crystallization, thermal stability and mechanical properties of the composite fibers.     

Investigation of antibacterial properties of nano-ZnO assembled cotton fibers

Nano-ZnO assembled cotton fibers (NZCF) with excellent antibacterial properties were fabricated using microwave synthesis method. The effects of ZnO size, ZnO content, assembly times, microwave power and Zn²⁺ concentration of the synthesis solution on the antibacterial activity of the NZCF were studied using bacteriological tests such as Petri dish and agar diffusion method. The results show that NZCF has the antibacterial circle width (ACW) of about 1.5–2.3 mm and 2.3–3.4 mm against Escherichia coli (E. coli, gram-positive organism) and Staphylococcus aureus (S. aureus, gram-negative organism), respectively. It is also found that the antibacterial activity of NZCF increases with decreasing ZnO size, increasing ZnO content in NZCF and increasing Zn²⁺ concentration in synthesis solution.     

Design,Semisynthesis, Insecticidal and Antibacterial Activities of a Series of Marine-Derived Geodin Derivatives and Their Preliminary Structure–Activity Relationships

To enhance the biological activity of the natural product geodin (1), isolated from the marine-derived fungus Aspergillus sp., a series of new ether derivatives (2–37) was designed and semisynthesized using a high-yielding one-step reaction. In addition, the insecticidal and antibacterial activities of all geodin congeners were evaluated systematically. Most of these derivatives showed better insecticidal activities against Helicoverpa armigera Hübner than 1. In particular, 15 showed potent insecticidal activity with an IC₅₀ value of 89 μM, comparable to the positive control azadirachtin (IC₅₀ = 70 μM). Additionally, 5, 12, 13, 16, 30 and 33 showed strong antibacterial activity against Staphylococcus aureus and Aeromonas salmonicida with MIC values in the range of 1.15–4.93 μM. The preliminary structure–activity relationships indicated that the introduction of halogenated benzyl especially fluorobenzyl, into 1 and substitution of 4-OH could be key factors in increasing the insecticidal and antibacterial activities of geodin.