Physicochemical Investigations Research Articles

Physicochemical investigation on eco-sustainable food packaging: valorisation of Moringa fibre and rice bran with embedded ZnO nanoparticles

Physicochemical investigation on eco-sustainable food packaging: valorisation of Moringa fibre and rice bran with embedded ZnO nanoparticles

Physicochemical Investigations of Textile Wastewater and Process Parameter Optimization for Bio-decolorization of Congo Red Dye by Pseudomonas aeruginosa MT-2 Strain

Pollution caused by dyes is a major environmental threat, posing adverse impacts on humans, animals, and plants. Therefore, the remediation of such pollutants is essential to protect the environment. This study aimed to conduct physicochemical and bacteriological analyses of textile wastewater to isolate and identify potential native bacterial strains for the decolorization of Congo red dye. Physical and nutritional process parameters were optimized to achieve maximum decolorization. The biological and chemical oxygen demands of the analyzed textile waste water were found to be above the recommended limits. In this study, 19 Congo red -decolorizing bacteria were isolated, with one bacterial culture capable of growing at a higher dye concentration of 300 mg/L. This bacterium was characterized biochemically and genetically (using 16S rRNA sequencing) and identified as the Pseudomonas aeruginosa MT-2 strain. A maximum decolorization of 94.0% was achieved at an initial dye concentration of 150 mg/L, 35°C, and pH 8.0 under static conditions. The bacterial culture also showed resistance to heavy metals such as arsenic, lead, and chromium. The biodegradation of Congo red dye was confirmed through UV-vis spectral analysis and Fourier transform infrared spectrophotometry. The findings of this study demonstrate the high remediation potential of the MT-2 strain, making it suitable for possible use in dye biodecolorization at contaminated sites.

New Binary Adducts of Panobinostat with Different Carboxylic Acid Based NSAIDs: Structural Analysis and Physicochemical Properties Investigation

AbstractAdoption of multitarget, cost‐effective fixed‐dose medication combinations can help lower the pill load without increasing the risk of adverse events. In this study, three new 1:1 drug‐drug binary solid forms of panobinostat (PNB) and nonsteroidal anti‐inflammatory drugs (NSAIDs) were effectively synthesized by liquid‐assisted grinding and slow evaporation crystallization techniques. The obtained solid forms were extensively characterized by various analytical techniques. The structural investigation revealed that all molecular adducts formed salt with a comparable (10) graph set pattern created by heteromeric interactions formed between PNB and corresponding salt formers. To determine the dissolving behavior of the newly developed adducts, solubility tests were performed at various pH levels (pH 1.2 and pH 7), and the results indicated that the solubility of all forms is increased at pH 7.0, particularly PNB.NIF has a solubility of 0.195 mg/mL, which is seven times higher than the parent drug. Furthermore, PXRD was used to assess the stability of the synthesized adduct at varied temperature and humidity levels and it was found that all the adducts are stable. Based on the findings, we hope that the newly found PNB drug‐drug binary adducts have possible potential to broaden the use of drug combinations without changing the chemical structures.

Physicochemical Investigations of Magnetite Persulfate Ozone Hybrid System for the Removal of Tartrazine Dye from Aqueous Solution

ABSTRACT This study involved the synthesis of magnetite nanoparticles by co-precipitation method. The synthesized nanoparticles were subsequently evaluated for their catalytic efficacy in the degradation and ozonation of tartrazine dye (TTD), employing sodium persulfate as a catalyst both in the presence and absence of ozone. The material characterization revealed that synthesized Fe3O4 nanoparticles were proven to have a crystalline structure by XRD. While spherical agglomerates with a flower-like morphology were revealed by the SEM, similarly FT-IR detected Fe – O – Fe and O – H bond vibrations, boosting surface area and catalytic activity. The degradation of the TTD was assessed in a laboratory-scale reactor, and its progress was monitored using UV-visible spectrophotometry. A comparative analysis of the two methods revealed that the catalytic ozonation demonstrated superior efficacy compared to the catalytic degradation, achieving a maximum degradation of 94.35% within 25 min of contact time. Optimal degradation parameters included a TTD concentration of 50 ppm, magnetite dosage of 0.75 g, persulfate concentration of 8 mm, and ozone inlet concentration of 5 g/L at pH 3. Evaluation of the degradation kinetics indicated the second-order kinetics model as the most appropriate, suggesting a physicochemical nature of the dye removal process. Furthermore, the study demonstrates enhanced efficiency in TTD decomposition compared to conventional methods.

Moringa Oil and Carbon Phases of Different Shapes as Additives for Lubrication

Vegetable oils in the lubricant field are largely studied. Their efficiency depends on their viscosity parameters and their fatty acid composition. The actions of moringa oil used as a lubricant base and as a lubricant additive have been shown in this work. Graphite, carbon nanofibers, and carbon nanodots are carbon phases of different shapes used as solid additives. The tribological performances of lubricant blends composed of between 0.5 and 1 wt.% of particles have been evaluated using a ball-on-plane tribometer under an ambient atmosphere. No additional surfactant was used. The positive and important actions of a small amount of moringa oil added in the lubricant formulas are demonstrated. The results obtained allow us to point out the influence of the type and shape of particles. Physicochemical investigations allow us to propose a synergistic effect between the particles and moringa oil as additives in dodecane.

Physicochemical investigations on molecular interactions of adenine with aqueous D-glucose/D-maltose solvent media at varying temperatures and compositions

Adenine derivatives are used in pharmaceuticals, and carbohydrates like D-maltose and D-glucose which are often used as excipients or stabilizers in drug formulations. Studying their interactions can help in optimizing drug formulations for stability and effectiveness. Further, understanding their interactions, provide insights into flavor development, food stability, and potential applications in food technology. In this regard, we have analysed the physicochemical properties of adenine in aqueous saccharide solvent media which can contribute to various fields, including biochemistry, pharmaceuticals, catalysis, and material science, with use for both basic research and practical applications. So, in this research work, physicochemical properties of adenine have been investigated in aqueous and mixed aqueous (0.05, 0.10 and 0.15) mol kg−1 D-glucose/D-maltose solvent media at discrete temperatures (293.15–313.15) K and experimental pressure (0.1 MPa). The experimentally determined physical properties such as density, velocity of sound, and viscosity have been utilized for the estimation of several parameters such as apparent molar volume (Vϕ), limiting apparent molar volume (V0ϕ), hydration number (nH), limiting apparent molar expansivity (E0ϕ), Hepler’s constant (∂E0ϕ/∂T)P, apparent molar isentropic compression (Kϕ,s), limiting apparent molar isentropic compression (K0ϕ,s), viscosity B-coefficients, transfer parameters and thermodynamic parameters of viscous flow (Δμ01, Δμ02, TΔS02 and ΔH02). Further, the Co-sphere overlap model has been employed for the analysis of varied probable interactions operating in the prepared systems. The obtained results signify that in all solution systems, the solute–solvent interactions are advancing with rising temperature and concentrations of saccharides. Also, the structure breaking tendency of adenine has been investigated via inference of Hepler’s constant data and positive values of dB/dT data for all the investigated systems. Moreover, the deduced apparent specific volume data evidently specify that adenine has sweet taste in water and different concentrations of chosen saccharides.

Efficacy of Radical‐Scavenging Activity in Novel Diorganotin(IV) Complexes of Schiff Bases of Salicylaldehyde

AbstractBiopotent hybrid diorganotin(IV) complexes, derived from salicylaldehyde Schiff bases having general formula R2SnL, where LH = (OH)C6H4HC: NCR′(R″)CHR‴OH] [where R = Me or Bu], were logically designed, generated, and characterized using spectroscopic techniques, single‐crystal X‐ray investigations, and DFT studies. Different diorganotin(IV) complexes were synthesized because of interaction between diorganotin(IV) dichloride and sodium salts of Schiff bases of salicylaldehyde ligand in anhydrous refluxing THF at 1:1 and 1:2 molar ratio (Product A and B). The chelating property of Schiff bases replaces organo group from diorganotin(IV) dichloride. It creates an O2SnL type of complex when diorganotin(IV) dichloride and ligand interact in 1:2 ratio, which is this study's most fascinating aspect. The characterization of these complexes is aided by physicochemical and spectroscopic investigations, including IR and NMR (1H, 13C, and 119Sn). Single‐crystal X‐ray investigations, mass spectrum studies, and DFT investigations suggest the dimeric structure of these compounds. These diorganotin(IV) complexes have a dimeric structure containing hexacoordinated central tin atom. Two µ2─O atoms bridge the gap between two Sn(IV) atoms in the dimeric dimethyltin(IV) complexes. The DPPH assay results for radical scavenging activity and IC50 values demonstrate the antioxidative potential of diorganotin(IV).

Physicochemical and electrochemical investigation of lead sulphide-graphene oxide hybrid nanostructure for energy storage applications

The emerging trend of advanced electrodes with greater specific capacitance (Cs) and favourable cycle life is acquiring significant attention of transition metal sulphide composites for energy storage devices. Therefore, this study demonstrates the effective creation of lead sulphide-graphene oxide (PbS/GO) nanohybrid using a simple hydrothermal method, which restricts agglomeration and enhances the electrochemical properties of the developed electrodes. The scanning electron microscopy (SEM) examination verified the distribution of PbS flakes on GO sheets, improving the performance. The nanohybrid employed as an electrode in supercapacitors demonstrated a Cs of 1371.57 F/g at a current density (j) of 1 A/g in a 2.0 M KOH using a three-electrode setup. Remarkably, it retained an exceptional specific capacitance of 94.12 % over 4,000 cycles. Furthermore, the asymmetric configuration (PbS/GO//AC) achieves a more excellent Cs of 251 F/g at 1 A/g and an impressive energy density of 17 Wh/kg when operated at a power density of 252 W/kg. The outstanding electrochemical performance results from the extensive surface area (121.61 m2/g) and mesoporous nature of the hybrid electrode, which provides additional passages and electroactive sites for electrolyte interaction during the oxidation–reduction phenomenon. Additionally, the uniform decoration of PbS nanoflakes on conductive GO nanosheets decreases the agglomeration and contributes to the pseudocapacitive behaviour. Therefore, the exceptional performance of the PbS/GO hybrid electrode holds considerable promise for the advanced supercapacitors used in portable and wearable electronics.

Novel Pseudomonas putida-derived nanoliposomes enhance the inhibition of MCF-7 breast cancer cells by superb intracellular uptake of doxorubicin

In this study, we aimed to utilize phospholipids from the bacterium Pseudomonas putida (PP) as a plentiful, safe, and accessible resource for creating nanoliposomes to deliver doxorubicin (Dox) to MCF-7 breast cancer cells. This bacterium provides a cost-effective source of phospholipids commonly used in nanoliposome production, with no toxicity or adverse environmental impact. To this end, molecular dynamics (MD) simulations were first conducted to evaluate the feasibility of this approach and to analyze the behavior and interaction of Dox with the nanoliposomes. The phospholipids of PP were then extracted using Folch's technique. Subsequently, Dox-loaded PP-derived nanoliposomes (PNL-Dox) were developed using the thin-film method. The physicochemical properties of the fabricated nanocarrier were then investigated and the anticancer effects of this system were tested on MCF-7 cells. The results of the MD simulations indicated that Dox reacted with all of the phospholipids through hydrogen bonds without affecting the fluidity, stability, and thickness of the nanoliposome membrane. Additionally, a small number of Dox molecules interacted with the nanocarrier membrane, while the remaining were located in its interior. The physicochemical investigation results showed that PNL-Dox had an average particle size and zeta potential of 271.7 ± 7.1 nm and −8.8 ± 3.3 mV, respectively. Scanning electron microscopy revealed that the particles were spherical and did not show any signs of aggregation. Drug release of PNL-Dox was gradual at pH 7.4 and 6.5, with a significantly higher release at pH 6.5. In vitro studies demonstrated successful uptake of PNL-Dox by MCF-7 cells, resulting in cytotoxicity within 24 and 48 h of treatment. Also, it increased apoptosis and reduced the production of reactive oxygen species (ROS) in these cells. Our study showcased the potential of PP phospholipids to form a promising anti-cancer drug delivery system, opening up new possibilities for the treatment of all types of cancers.

Physicochemical and Electrochemical Investigation of Naturally Occurring Quinones for Application toward Electrochemically Mediated Carbon Dioxide Capture

Physicochemical and Electrochemical Investigation of Naturally Occurring Quinones for Application toward Electrochemically Mediated Carbon Dioxide Capture

Exploring Italian Autochthonous Punica granatum L. Accessions: Pomological, Physicochemical, and Aromatic Investigations.

Autochthonous Italian pomegranate accessions are still underexplored, although they could be an important resource for fresh consumption, processing, and nutraceutical uses. Therefore, it is necessary to characterize the local germplasm to identify genotypes with desirable traits. In this study, six old Italian pomegranate landraces and a commercial cultivar (Dente di Cavallo) were investigated, evaluating their fruit pomological parameters, physicochemical (TSS, pH, TA, and color) characteristics, sugar content, and aromatic profiles (HeadSpace Solid-Phase MicroExtraction (HS-SPME)) coupled with Gas Chromatographyass Spectrometry (GC-MS) of pomegranate juices. Significant differences were observed in the size and weight of the seed and fruits (127.50-525.1 g), as well as the sugar content (100-133.6 gL-1), the sweetness (12.9-17.6 °Brix), and the aroma profiles. Over 56 volatile compounds, predominantly alcohols (56%), aldehydes (24%), and terpenes (9%), were simultaneously quantified. Large variability among the genotypes was also statistically confirmed. The results indicate a strong potential for commercial exploitation of this germplasm, both as fresh and processed fruit, and highlight its versatility for diverse applications. The genetic diversity of the autochthonous pomegranate accessions represents a precious heritage to be preserved and enhanced. This work represents a preliminary step toward a more comprehensive characterization and qualitative valorization of the Italian pomegranate germplasm.

A preformulation study of marine alkaloid aaptamine: Physicochemical properties investigation and liposomal formulation development toward hepatocellular carcinoma treatment

AbstractHepatocellular carcinoma (HCC) is a global health concern with high prevalence and mortality. A marine alkaloid, AP‐427, has been reported to show potential for HCC treatment. However, its use is limited by low solubility and high toxicity. We aimed to investigate the preformulation parameters and develop AP‐427 liposomes to improve its clinical suitability. A stability‐indicating HPLC assay was established, and the physicochemical properties of AP‐427 were analyzed. Afterward, AP‐427 liposomes were prepared and characterized, and their cytotoxicity was evaluated. AP‐427 had a low solubility at physiological pH, a LogD of 2.56 ± 0.03, and a basic pKa of 3.24 ± 0.12. An entrapment efficiency of 52.71 ± 3.2% was achieved after optimization. The resulting AP‐427 liposomes were 147.2 ± 3.4 nm and stable up to three months when stored in a pellet form at 4°C. The crystallization of AP‐427 in liposomes became less ordered, and AP‐427 liposomes exhibited a controlled release fitted in Korsmeyer–Peppas model, indicating the release was driven by diffusion. Furthermore, AP‐427 liposomes showed a 3.6 times reduced cytotoxicity against HepG2 cells compared with free AP‐427, potentially enhancing its antitumor efficacy. In conclusion, the precise preformulation parameters advanced the AP‐427 liposomal formulation development, which showed potential for HCC treatment.Practical Applications: The aaptamine derivative AP‐427 has shown cytotoxic effects against hepatocellular carcinoma. However, the low solubility and high toxicity limit its clinical application. The present study aims to prepare liposomal formulation to solve the current problems. Results obtained from this study shed light on challenges related to drug solubility and have paved the way for the development of an effective AP‐427 liposomal formulation with promising application in hepatocellular carcinoma therapy.

Bio‐Extract Mediated Synthesis of Y/Fe2O3 Nanoparticles Using Adenanthera pavonina L. and Their Photocatalytic and Antibacterial Activities

AbstractThe present study uses Adenanthera pavonina L. plant extract to synthesize Y/Fe2O3 nanoparticles in a sustainable and efficient manner. Several physicochemical investigations were performed on the synthesized Y/Fe2O3 to evaluate its structure and morphological characteristics. The high crystallinity of Fe2O3 and decreased crystal size of Y/Fe2O3 were revealed by the XRD study. The formulated Y/Fe2O3 was spherical in shape. Y/Fe2O3 has shown potential photocatalytic activity in the degradation of congo red and brilliant green dyes in the presence of visible light. Degradation efficiency is higher than 90% for both dyes. In addition, the antibacterial activity of Y/Fe2O3 was measured against pathogenic strains of Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Proteus mirabilis, Pseudomonas putida, Shigella dysenteriae, and Staphylococcus aureus. Y/Fe2O3 showed promising antibacterial activity against all microorganisms. Micrococcus luteus showed a higher zone of inhibition (equal to 35 mm in diameter) than other microorganisms using Y/Fe2O3. Thus, it is established that the green synthesized Y/Fe2O3 nanoparticles are active catalysts for the photocatalytic degradation of hazardous dyes and have antibacterial properties against different bacterial stains.

Solubility Reinforcement using Binary Solvent Mixtures and its use in Development and Validation of UV-Spectrophotometric Method for Posaconazole

Objectives: To develop a method that meets the requirements as per ICH guidelines for validation and can be used as simple, specific, economical, and repeatable for routine quality control analysis of formulations containing Posaconazole. Materials and Methods: The maximum absorbance of Posaconazole was successfully recorded using a precise 1:1 ratio of binary solvent system Methanol: Buffersolution pH 7.4 at 262nm. Results: After a preliminary physicochemical investigation the precipitation of the Posaconazole issue was resolved using a precise 1:1 ratio of binary solvent system Methanol: Buffersolution pH 7.4. Development and validation of the analytical method was done using the same binary solvent system. The maximum absorbance with this solvent system was found at 262nm, while the calibration curve shows a Regression coefficient (R2) of about 0.9984 for its linearity in the concentration range of 2.5 to 15µ/ml. The developed method was validated and meets the requirements as per ICH (International Conference for Harmonization) guidelines where the Limit of Detection (LOD) as well as Limit of Quantification (LOQ) were noted as 0.74µ/ml and 2.25µ/ml. Percentage recovery was within the permissible range (with a % relative standard deviation of less than 2.0). Conclusion: The results from validation parameters specifically accuracy or % recovery and robustness study reveal that the developed method meets the requirements and can be used as simple, specific, economical, and repeatable for routine quality control analysis of formulations containing Posaconazole.

Efficient removal of Cr(VI) ions from industrial wastewater using carbon-based adsorbents functionalized with boronic acid

Abstract The adsorption of potentially toxic element ions from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Potentially toxic element ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, designability, and stability have been proposed. In this study, a carbon-based adsorbent, named Magnetic Nitrogen-Doped Carbon (M-NC), and graphene oxide were developed for the selective removal of potentially toxic element ions. To increase the potential for HM immobilization, sulfide-modified biochar was created via a process called simultaneous carbon layer encapsulation. A theoretical physicochemical and thermodynamic investigation of the adsorption of potentially toxic elements s Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was performed with statistical physics fundaments. The biochar with large surface areas is used to remove potentially toxic element ions, one of the most important potentially toxic element pollutants, from aqueous solutions. The capacity of the adsorbent for removing potentially toxic element ions was studied using Langmuir adsorption isotherm under ultrasound-assisted conditions. The MNCs can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous statistical physics adsorption model was used to describe and analyze the experimental potentially toxic element removal isotherms at 30 °C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The findings show the proposed adsorbent, with an efficiency of 98.7 % and even reaching 99.3 % in certain cases, making it a standout choice for potentially toxic element removal applications. This research holds significance in advancing the understanding of environmentally sustainable potentially toxic element removal processes, particularly in the context of biomass-derived adsorbents, offering potential solutions for water purification and environmental remediation.

Physicochemical and Structural Investigation of Argeli (Edgeworthia gardneri) Bast Fibers

Physicochemical and Structural Investigation of Argeli (Edgeworthia gardneri) Bast Fibers

Groundwater quality analysis in Hail region of northwest Saudi Arabia based on physicochemical investigation

The acquired groundwater data from seventeen wells were hydrochemically analyzed for Sulfate, Chloride, Ammonia, Nitrate, Nitrite, pH, EC (Electrical Conductivity), TDS (Total Dissolved Solids), total hardness, and total alkalinity concentrations and then compared to the national and international standards. The results range as follows: pH (6.65–8.26), EC (382–1214 μS·cm−1), Total hardness (72–310 ppm), TDS (258–775 ppm), Total alkalinity (54–138 ppm), Cl- (19–202 ppm), Ammonia (NH3) (0.0 to 1.5 mg/liter), Nitrate (NO3) (4.7 to 65.6 ppm), Nitrite (NO2) (0.007 to 0.05 ppm), and sulfate (SO4) (29–278 ppm). About 70.58 % of the study area’s groundwater samples have TDS levels below 500 mg/l, which are considered safe for drinking. The EC of the groundwater found that 100 % of the samples fall within the allowed level. Based on these results, the groundwater quality is suitable for drinking and irrigation purposes in Hail region. Hence, this research shows that using GIS and chemical analysis of groundwater could be useful tools for the decision-making process of local and international authorities and water resources management.

Molecular interactional study of SDS and CTAB in aqueous medium of anti-HIV drugs (Emtricitabine and Lamivudine) at different temperatures: A physicochemical investigation

The present study deals with the interactions of Emtricitabine and Lamivudine (anti-HIV drugs) with anionic surfactant sodium dodecylsulphate (SDS) and cationic surfactant cetyltrimethylammonium bromide (CTAB) at (298.15–313.15) K temperature range by volumetry, compressibility and viscometric approach. The experimental values of sound velocity and density are used to compute various parameters such as apparent molar volume (φv), isentropic compressibility (κs), and apparent molar adiabatic compression (φκ) by employing cosphere overlap model. Relative viscosity parameter (ηr) evaluated from viscosity data also helps to understand various interactions prevalent in surfactant-drug-water ternary system. This attempt of extracting information about various physicochemical interactions of anti-HIV drugs with surfactants can prove beneficial to develop novel anti-HIV agents with better viral resistance activity.

Investigating the performance of CoFe2O4@TiO2 nanomaterial as multifunctional cathode catalyst for simultaneous dye degradation and oxygen reduction in microbial desalination cell

Microbial desalination cell (MDC) is an emerging technology in which water is desalinated and energy is generated by the breakdown of organic compounds and catalyzed by microorganisms using the potential gradient created in the reactor. MDC efficacy is substantially influenced by the oxygen reduction reaction (ORR) occurring at the cathode, albeit potential hindrances include sluggish reaction rates and biofouling development. The present study involved synthesizing and utilizing CoFe2O4@TiO2 nanocomposite as a multifunctional catalyst on a cathode surface for efficient ORR and dye removal. XPS, HRTEM, and XRD techniques were used to ascertain the NPs' morphology, surface properties, dimensions, and XRD patterns. Physicochemical investigation showed that the nanoparticles had a consistent distribution, a mean diameter of 18.11 nm, and a spherical shape. Researchers tested MDCs with nanoparticles (NPs). The highest power density was 4.56 W/m3, 50 % more than the MDC with a lower loading density. The desalination efficiency was found to be 60 % at 1.5 mg/cm2 CoFe2O4@TiO2, however, it was 80 and 81 % at 2.5 and 2.0 mg/cm2 catalyst concentrations, respectively. The dye degradation efficiency of as high as 88 % was observed with CoFe2O4@TiO2 nanocomposite cathode MDC. The findings show that CoFe2O4@TiO2 nanocomposite might be an economically feasible ORR catalyst, improving MDC efficiency and cost.

The Extracellular Metallometabolome: Metallophores, Metal Ionophores, and Other Chelating Agents as Natural Products

Natural products include inorganic as well as organic compounds. Living organisms face constant challenges in acquiring essential metal ions and getting rid of non-essential ones with toxic actions. They employ an extracellular biochemistry in these tasks and use it to engage in a chemical warfare against invaders and competitors by either increasing or decreasing the availability of metal ions for maintaining their welfare in aquatic or terrestrial ecological niches. To control mutualistic, cambialistic or parasitic symbiosis with other organisms they use a remarkably rich suite of secreted bioactive molecules with ligand donor atoms for metal binding. This overview discusses the interactions of these extracellular natural products with a multitude of metal ions in the periodic system of the elements. It focuses mainly on metallophores and metal ionophores secreted from bacteria, fungi, and plants, but metal-carrying cofactors and other chelating agents will also be mentioned in the context of related functions and with an intent to categorize. The intracellular fate of the metal ions and the controlled pathways for the biosynthesis, secretion, uptake, biodegradation or recycling of the secreted natural products that interact with metal ions will not be covered. Metallophores make extracellular metal ions available via delivery to specific transporters and unavailable to competing organisms, especially pathogens, though some invaders have developed ways to compete efficiently for metal ions. The classic concept of siderophores, carriers of iron(III) ions, is extended here to specific and broad-band metallophores for metal ions such as copper (chalkophores), zinc (zincophores), and yet others. Metal ionophores, in contrast, transport metal ions through biological membranes. There is a wide variety of chemical structures for either metallophores or metal ionophores. Together with physicochemical investigations of metal complexation und conditions mimicking the natural environment, “omics” mining and mapping the diversity of chemotypes is an on-going effort with analytic, genetic, and bioinformatic tools and comes together in defining the metallometabolome, which combines the metabolome and the metallome. Investigations are highly multidisciplinary, include an important, but academically infrequently crossed bridge between the biosciences (biochemistry) and the earth sciences (geochemistry), define significant applications in the pharmaceutical/medical sciences regarding immune modulation and the control of virulence at the host-pathogen interface, and have implications for the nutritional/toxicological and environmental/ecological sciences.