Multifunctional green synthetized gold nanoparticles/chitosan/ellagic acid self-assembly: Antioxidant, sun filter and tyrosinase-inhibitor properties

Anti-tyrosinase and anti-melanogenic effects of piperine isolated from Piper nigrum on B16F10 mouse melanoma cells

The essential function of melanin is to protect our skin against harmful environmental factors. However, excessive melanin production can cause undesirable hyperpigmentation issues, such as freckles and melasma. Although several compounds are used to control melanin production by inhibiting tyrosinase (TYR), their efficacy is limited by skin-related adverse effects and cytotoxicity concerns. Consequently, searching for new natural compounds with an effective TYR inhibitor (TYR-I) activity but less harmful effects continues. Plant-based natural extracts are an alternative that are in great demand due to their safety and diverse biological properties. This study assessed ten isolated plant compounds for their TYR-I activities using an in vitro mushroom TYR inhibition assay. Among these compounds, piperine (400 μM) demonstrated the highest TYR-I activity, with a potency of 36.27 ± 1.96 %. Hence, this study examined the effect of piperine on melanogenesis in melanocyte stimulating hormone-treated B16F10 melanoma cells and using kojic acid as a positive reference. Cell viability was evaluated through the standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Measurements of cellular TYR activity and melanin content were performed and related to changes in the transcriptional expression levels of melanogenesis-related genes, assessed via quantitative real-time reverse transcriptase (RT-q)PCR analysis. The results revealed that piperine at a concentration of 44 μM significantly reduced cellular TYR activity by 21.51 ± 2.00 % without causing cytotoxicity. Additionally, at the same concentration, piperine significantly decreased the intracellular melanin content by 37.52 ± 2.53 % through downregulating transcription levels of TYR and TYR-related protein 1 (TRP-1) but not TRP-2. Kojic acid, at a concentration of 1407 μM, induced a significant decrease in the melanin content and cellular TYR activity by suppressing all three melanogenesis-related genes. These findings suggest that piperine has potential as a potent depigmenting agent.

Construction of quercetin-fucoidan nanoparticles and their application in cancer chemo-immunotherapy treatment

Fucoidan (FU), a natural marine polysaccharide, is an immunomodulator with great potential in tumor immunotherapy. In this work, a FU encapsulated nanoparticle named QU@FU-TS was developed, which contained the anticancer phytochemical quercetin (QU) and had the potential for cancer chemo-immunotherapy. QU@FU-TS were constructed through molecular self-assembly using green material tea saponin (TS) as the linking molecule. The molecular dynamics (MD) simulation showed that QU was bound to the hydrophobic tail of TS. At the same time, FU spontaneously assembled with the hydrophilic head of TS to form the outer layer of the QU@FU-TS. The molecular interactions between QU and TS were mainly π-stacking and hydrogen bonds. The bonding of FU and TS was maintained through the formation of multiple hydrogen bonds between the sulfate ester group and the hydroxy group. The inhibitory effects of QU@FU-TS on A549 cell proliferation were more potent than that by free QU. The antitumor activity of QU@FU-TS was mediated through various mechanisms, including the induction of oxidative stress, blocking cell cycle progression, and promoting cell apoptosis. Moreover, QU@FU-TS has been demonstrated to impede the proliferation and migration of cancer cells in vivo. The expression levels of macrophage surface markers increased under the treatment of QU@FU-TS, suggesting the potential of QU@FU-TS to serve as an immunotherapeutic agent by promoting macrophage activation.

Control of biomaterial-associated infections through biofabrication of gold nanoparticles using Musa sapientum extract

Biofilm-associated infections are a critical element in infectious diseases and play an important role in antibiotic resistance. Biosynthesized gold nanoparticles (AuNPs) using ethanolic extract of Musa sapientum unripe fruit were performed. The nanoparticles demonstrated an absorption peak at 554 nm with particle sizes ranging from 5.45 to 104.44 nm. High negative zeta potential value of -33.97 mV confirmed the high stability of AuNPs. The presence of bioconstituents responsible for capping and stabilization was indicated by intensity changes of several peaks from Fourier-transform infrared spectroscopy analysis. The minimum inhibitory concentrations (MIC) of the biosynthesized AuNPs against important pathogens ranged from 10 to 40 μg mL-1 . Synthesized nanoparticles at 0.062 to 0.5 × MIC significantly inhibited biofilm formation in all the tested microorganisms (p < 0.05). Scanning electron microscopy and confocal scanning laser microscopy images clearly illustrated in disruption and architectural changes of microbial biofilms at sub-MIC of biosynthesized AuNPs. Excellent antioxidant and antityrosinase activities of AuNPs were observed. The biosynthesized AuNPs at 20 μg mL-1 significantly inhibited nitric oxide production by 93% in lipopolysaccharide-stimulated RAW 264.7 cells, compared with control (p < 0.05). The biosynthesized AuNPs at 0.6 to 40 μg mL-1 demonstrated no toxic effects on L929 fibroblast cells.

Investigation of in vitro antimicrobial, antioxidant and antiproliferative activities of Nostoc calcicola biosynthesized gold nanoparticles

The cyanobacteria are the promising candidate for synthesizing gold nanoparticles (AuNPs), due to their ability to accumulate heavy metals from the cellular environment and additionally contain varied bioactive compounds as reducing and stabilizing agents. This study describes the N2-fixing cyanobacterium Nostoc calcicola-mediated bioreduction of AuNPs and the inherent antimicrobial, antioxidant, and antiproliferative activities in vitro. Biosynthesized Nc-AuNPs were characterized by spectral characterization techniques. The formation of AuNPs was physically confirmed by the colour change from pale green to dark violet. The UV-Vis analysis, further, proved the reduction in Nc-AuNPs with the cyanobacterium and showed a spectral peak at 527 nm. FESEM-EDX images suggested the surface morphology of the NPs as spherical, cuboidal, and size between 20 and 140 nm. The antimicrobial studies of Nc-AuNPs were carried out by agar-well diffusion method and MIC values against five pathogenic bacterial and two fungal strains were noted. The AuNPs exhibited potential antimicrobial activity against h-pathogenic bacteria with inhibitory zones ranging at 11-18 mm; against fungi ranging at 13-17 mm. Significant antioxidant potentialities were explored by a DPPH assay with an IC50 value of 55.97 μg/ mL. Furthermore, in the anticancer efficacy assay, the Nc-AuNPs inhibited cellular proliferation in human breast adenocarcinoma and cervical cancer cell lines at IC50 concentration, 37.3 μg/ml, and 44.5 μg/ml, respectively. Conclusively, N. calcicola would be an excellent source for synthesizing stable colloidal AuNPs that had significant credibility as phycological (algal) nanomedicines as novel prodrugs with multiple bioactivities.

Promising remedies for cardiovascular disease: Natural polyphenol ellagic acid and its metabolite urolithins

BACKGROUND

Cardiovascular disease (CVD) is a significant worldwide factor contributing to human fatality and morbidity. With the increase of incidence rates, it is of concern that there is a lack of current therapeutic alternatives because of multiple side effects. Ellagic acid (EA), the natural polyphenol (C₁₄H₆O₈), is abundant in pomegranates, berries, and nuts. EA and its intestinal microflora metabolite, urolithins, have recently attracted much attention as a potential novel "medicine" because of their wide pharmacological properties.

PURPOSE

This study aimed to critically analyze available literature to summarize the beneficial effects of EA and urolithins, and highlights their druggability and therapeutic potential in various CVDs.

METHODS

We systematically studied research and review articles between 1984 and 2022 available on various databases to obtain the data on EA and urolithins with no language restriction. Their cardiovascular protective activities, underlying mechanism, and druggability were highlighted and discussed comprehensively.

RESULTS

We found that EA and urolithins may exert preventive and curative effects on CVD with negligible side effects and possibly regulate lipid metabolism imbalance, pro-inflammatory factor production, vascular smooth muscle cell proliferation, cardiomyocyte apoptosis, endothelial cell dysfunction, and Ca²⁺ intake and release. Potentially, this may lead to the prevention and amelioration of atherosclerosis, hypertension, myocardial infarction, cardiac fibrosis, cardiomyopathy, cardiac arrhythmias, and cardiotoxicities in vivo. Several molecules and signaling pathways are associated with their therapeutic actions, including phosphatidylinositol 3-kinase/protein kinase B, mitogen-activated protein kinase, NF-κB, nuclear factor erythroid-2 related factor 2, sirtuin1, miRNA, and extracellular signal-regulated kinase 1/2.

CONCLUSION

In vitro and in vivo studies shows that EA and urolithins could be used as valid candidates for early prevention and effective therapeutic strategies for various CVDs.

Chitosan/snail slime films as multifunctional platforms for potential biomedical and cosmetic applications: physical and chemical characterization

Due to the pollution problem, the use of more sustainable materials with a reduced environmental impact, spanning across biocompatible and biodegradable polymers, is growing worldwide in many different fields, particularly when referring to applications in Life Sciences. Accordingly, with the aim of developing multifunctional materials for potential cosmetic/biomedical purposes, this work reports the physical and chemical characterization of chitosan-based films blended with snail slime, exhibiting antioxidant and sunscreen features. A suitable formulation for preparing free-standing chitosan platforms, mixing low molecular weight chitosan, lactic acid, glycerol, and snail slime into an appropriate ratio, is thus described. The results obtained by morphological analysis and ATR-FTIR spectroscopy, XRD, swelling analysis (also when varying pH, ionic strength, and temperature), and WVTR measurements evidence a uniform distribution of snail slime inside the chitosan network, forming more compacted structures. At first, the UV-Vis analysis is used to investigate the theoretical Sun Protection Factor, finding that these innovative platforms can be used for preventing sunburn. Then, the antioxidant features are investigated using the ABTS assay, displaying a snail slime-mediated and dose-dependent boosted activity.

Processing, Characterization and Disintegration Properties of Biopolymers Based on Mater-Bi® and Ellagic Acid/Chitosan Coating

Among the most promising synthetic biopolymers to replace conventional plastics in numerous applications is MaterBi^® (MB), a commercial biodegradable polymer based on modified starch and synthetic polymers. Actually, MB has important commercial applications as it shows interesting mechanical properties, thermal stability, processability and biodegradability. On the other hand, research has also focused on the incorporation of natural, efficient and low-cost active compounds into various materials with the aim of incorporating antimicrobial and/or antioxidant capacities into matrix polymers to extend the shelf life of foods. Among these is ellagic acid (EA), a polyphenolic compound abundant in some fruits, nuts and seeds, but also in agroforestry and industrial residues, which seems to be a promising biomolecule with interesting biological activities, including antioxidant activity, antibacterial activity and UV-barrier properties. The objective of this research is to develop a film based on commercial biopolymer Mater-Bi^® (MB) EF51L, incorporating active coating from chitosan with a natural active compound (EA) at two concentrations (2.5 and 5 wt.%). The formulations obtained complete characterization and were carried out in order to evaluate whether the incorporation of the coating significantly affects thermal, mechanical, structural, water-vapor barrier and disintegration properties. From the results, FTIR analysis yielded identification, through characteristic peaks, that the type of MB used is constituted by three polymers, namely PLA, TPS and PBAT. With respect to the mechanical properties, the values of tensile modulus and tensile strength of the MB-CHI film were between 15 and 23% lower than the values obtained for the MB film. The addition of 2.5 wt.% EA to the CHI layer did not generate changes in the mechanical properties of the system, whereas a 5 wt.% increase in ellagic acid improved the mechanical properties of the CHI film through the addition of natural phenolic compounds at high concentrations. Finally, the disintegration process was mainly affected by the PBAT biopolymer, causing the material to not disintegrate within the times indicated by ISO 20200.

Different additives of gold nanoparticles and lithium oxide loaded chitosan based films; controlling optical and structural properties, evaluating cell viability

Natural chitosan-based films (CS) were fabricated by changing ingredient corporations between gold nanoparticles (AuNPs), lithium oxide (Li₂O), and graphene oxide (GO). A Series of films with different components were obtained. The structural examination is executed by XRD, FTIR, and EDX to analyze crystal structure, chemical bonding, and chemical contents, respectively. The findings illustrated that, the Li₂O@CS exhibited the lowest contact angle with 70 ± 4.6°. Scanning Electron Microscopy (SEM) displayd rod-shaped AuNPs with an average length of 0.3 μm and an average width of 90 nm. The refractive index of CS recorded 2.142, while AuNPs/Li₂O/GO@CS slightly declined to 2.085. Concerning AuNPs/Li₂O/GO@CS, the detected cell viability percentage of normal lung cells among the usage of 156.25 μg/mL is 98.91%, while 9.77 μg/mL achieved 125.78%. Therefore, combining AuNPs, GO and Li₂O within the CS matrix results in films of boosted biocompatibility and can be suggested for medical applications.

Chitosan-Mediated Environment-Friendly Synthesis of Gold Nanoparticles with Enhanced Photonic Reactivity

We developed a very simple, efficient and environment-friendly synthesis method for the manufacturing of high-performance chitosan-capped gold nanoparticles that could be used for biosensing applications. Gold nanoparticles were prepared through the spontaneous reduction of chloroauric acid by chitosan, which was used as both a reducing and a stabilizing agent. The samples were heated to a temperature of 60 °C under ultrasonic conditions. The composite system made of chitosan as a matrix and gold nanoparticles demonstrated a high stability in an aqueous buffer solution. The nanoparticles displayed an enhancement in photonic performance compared with the same property of individual components as a result of surface plasmon resonance at the interface between the structural phases of the hybrid structure. The enhanced photonic reactivity of the hybrid nanostructure may offer new insights for future possible biosensing applications.

Simultaneous loading of (-)-epigallocatechin gallate and ferulic acid in chitosan-based nanoparticles as effective antioxidant and potential skin-whitening agents

Chitosan (CS) based nanoparticles simultaneously loaded with (-)-epigallocatechin gallate (EGCG) and ferulic acid (FA) were fabricated via ionic gelation method modified by sodium tripolyphosphate and genipin (G-CS-EGCG-FA NPs). The particle size, morphology, entrapment efficiency, rheological properties, antioxidant and tyrosinase inhibitory activity of NPs were investigated. The G-CS-EGCG-FA NPs exhibited irregular ellipsoidal shape with average diameter of 412.3 nm and high DPPH and ABTS·⁺ scavenging ability. The entrapment efficiency of EGCG and FA in NPs was 46.0 ± 1.3 % and 46.8 ± 1.6 %, respectively. CS-based NPs show no toxic effects on NIH 3 T3 cells and B16-F10 melanoma cells with concentration <200 μg/mL and 25 μg/mL, respectively and the cell viability ranged from 100 % to 118 %. Meanwhile, the oxidative repaired capacity of G-CS-EGCG-FA NPs (200 μg/mL) in H₂O₂-induced cells was over 100 %, higher than that of the same dose of free EGCG or FA. Moreover, the tyrosinase inhibition activity of G-CS-EGCG-FA NPs (25 μg/mL) (84.6 %) was more potent than that of free EGCG (55.3 %), free FA (47.1 %) and kojic acid, indicating the good skin repairing and whitening ability of G-CS-EGCG-FA NPs. Given these results, this research provides new insights for designing novel particles loaded with dual bioactive agents that possess synergistic benefits.

Structural characterization and anti-inflammatory properties of green synthesized chitosan/compound K‑gold nanoparticles

Ginsenoside compound K (CK) has been shown to exhibit anti-inflammatory properties. In this study, to encourage biomedical applications of biosynthesized gold nanoparticles (AuNPs) with anti-inflammatory effects, AuNPs loaded with ginsenoside compound K were prepared using a self-assembly technique with chitosan as the carrier. Optimal conditions for chitosan-ginsenoside CK‑gold nanoparticles (CS-CK-AuNPs) formation were monitored using UV-Vis absorption spectroscopy. The physicochemical characterization of CS-CK-AuNPs was performed using FE-TEM, FE-SEM, XRD, DLS, FTIR and NMR techniques. In the stability test, CS-CK-AuNPs did not show any significant changes up to 4 weeks. Fluorescence imaging demonstrated that CS-CK-AuNPs promoted cellular uptake in vitro, but did not exhibit significant cytotoxicity at concentrations below 40 μg/mL. Additionally, the CS-CK-AuNPs inhibited NO production, and reduced the expression and secretion of inflammatory cytokines (IL-1β, IL-6, and TNF-α) via inhibition of the nuclear factor-kappaB (NF-κB) pathway in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Thus, CS-CK-AuNPs are novel candidates for developing anti-inflammatory agent. This study also confirms the superiority of chitosan AuNPs as oral delivery vehicles for inflammation-related diseases.

The “End Life” of the Grape Pomace Waste Become the New Beginning: The Development of a Virtuous Cycle for the Green Synthesis of Gold Nanoparticles and Removal of Emerging Contaminants from Water

During the last decades, the demand for processes developed according to the Circular Economy Principles has increased, searching for an alternative life for wastes. For this purpose, a one-pot green approach is exploited during this work to synthesize gold nanoparticles (AuNPs) by using grape pomace waste from Vitis vinifera. A raw aqueous extract of grape seeds, skin, and stems is used for AuNPs synthesis. UV-Vis, XPS, SEM, and ATR-FTIR spectroscopies demonstrate the main role of the extract’s polyphenolic components in stabilizing nanoparticles. XRD, DLS, and Zeta Potential analyses were used to characterize AuNPs. Moreover, the ionic strength, pH, and temperature role was investigated through the Surface Plasmon Resonance (SPR) band observation to assess AuNPs’ stability and photostability. For foreseeing the as-synthesized AuNPs’ potential use in cosmetic and biomedical fields as multifunctional platforms, their antioxidant, and skin-lightening properties were tested, together with their sunscreen ability. A preliminary in-vitro evaluation is reported about the AuNPs’ cytoprotective effects against H₂O₂ oxidative stress-induced in normal human dermal fibroblasts. Briefly, the possibility of reusing the grape pomace waste after the AuNPs synthesis as an adsorbent for the efficient removal of emergent contaminants is preliminarily discussed in the paper, further valorizing the use of waste according to a bio circular approach.

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives

Modern society has been facing serious health-related problems including food safety, diseases and illness. Hence, it is urgent to develop analysis methods for the detection and control of food contaminants, disease biomarkers and pathogens. As the traditional instrumental methods have several disadvantages, including being time consuming, and having high cost and laborious procedures, optical nanosensors have emerged as promising alternative or complementary approaches to those traditional ones. With the advantages of simple preparation, high surface-to-volume ratio, excellent biocompatibility, and especially, unique optical properties, gold nanoparticles (AuNPs) have been demonstrated as excellent transducers for optical sensing systems. Herein, we provide an overview of the synthesis of AuNPs and their excellent optical properties that are ideal for the development of optical nanosensors based on local surface plasmon resonance (LSPR), colorimetry, fluorescence resonance energy transfer (FRET), and surface-enhanced Raman scattering (SERS) phenomena. We also review the sensing strategies and their mechanisms, as well as summarizing the recent advances in the monitoring of food contaminants, disease biomarkers and pathogens using developed AuNP-based optical nanosensors in the past seven years (2015-now). Furthermore, trends and challenges in the application of these nanosensors in the determination of those analytes are discussed to suggest possible directions for future developments.

Ellagic Acid: A Review on Its Natural Sources, Chemical Stability, and Therapeutic Potential

Ellagic acid (EA) is a bioactive polyphenolic compound naturally occurring as secondary metabolite in many plant taxa. EA content is considerable in pomegranate (Punica granatum L.) and in wood and bark of some tree species. Structurally, EA is a dilactone of hexahydroxydiphenic acid (HHDP), a dimeric gallic acid derivative, produced mainly by hydrolysis of ellagitannins, a widely distributed group of secondary metabolites. EA is attracting attention due to its antioxidant, anti-inflammatory, antimutagenic, and antiproliferative properties. EA displayed pharmacological effects in various in vitro and in vivo model systems. Furthermore, EA has also been well documented for its antiallergic, antiatherosclerotic, cardioprotective, hepatoprotective, nephroprotective, and neuroprotective properties. This review reports on the health-promoting effects of EA, along with possible mechanisms of its action in maintaining the health status, by summarizing the literature related to the therapeutic potential of this polyphenolic in the treatment of several human diseases.

Conditions adjustment of polycaprolactone nanofibers scaffolds encapsulated with core shells of Au@Se via laser ablation for wound healing applications

Au@Se core-shell nanoparticles were obtained via laser ablation technique to be incorporated into polycaprolactone (PCL) nanofibrous scaffolds for wound healing applications at different contributions of Se nanoparticles (SeNPs). The synthesized layers were inspected via X-ray diffraction (XRD) and Fourier transformed infrared (FTIR). Additionally, microstructural and surface morphology were followed with different SeNPs contributions before and after fibroblast culturing. Moreover, Selenium dopant is affected Maximum roughness valley depth while it starts from 0.31 µm at Au@0.0Se@PCL reaching 0.457 µm at Au@12Se@PCL; however, after culturing starts from 0.3833 µm reaching 0.41 µm. Besides, the antibacterial activity was screened, showing the absence of inhibition zones in free selenium composition; however, it grows up reaching 8.3 ± 0.8, and 8.0 ± 0.8 for E. coli and S. aureus, respectively at the maximum contribution of selenium. SeNPs contributed composites show higher cell viability than Selenium free composite that it reaches its max in Au@8.0Se@PCL, recording 95.3 ± 2.3%. Composites show an excellent Wound dressing capability that its performance is directly proportional to selenium content. This significant enrichment of antibacterial activity and cell viability could recommend these composites for additional research in medical applications.

Snail slime-based gold nanoparticles: An interesting potential ingredient in cosmetics as an antioxidant, sunscreen, and tyrosinase inhibitor

Due to their properties, snail slime-based products have been appreciated and used worldwide. So, as an alternative and innovative use of snail slime, it was adopted to induce gold nanoparticles' formation, conferring them interesting properties. By a simple, one-pot, and eco-friendly approach, 14 ± 6 nm wide hybrid gold nanoparticles, having an inorganic metallic core decorated by the slime's main components, were obtained. Among their several properties, their antioxidant and tyrosinase inhibition activity were investigated through the DPPH and ABTS and the tyrosinase assays, respectively. After assessing their non-cytotoxicity in our previous work, the results revealed positive responses, enabling their use as a potential novel multifunctional ingredient in cosmetics. Interestingly, the gold nanoparticle photostability, investigated by means of a solar simulator lamp, suggests using them in commercial cosmetic sunscreen products as a potential alternative to the commonly used inorganic sunscreen ingredients. The theoretical Sun Protection Factor was evaluated, obtaining values in the range 0-12. The proposed environmentally friendly and cost-effective protocol for nanoparticle synthesis, following the principles of Green Chemistry, opens a hugely attractive space toward the study of snail slime-based gold nanoparticles as a potential multipurpose platform in cosmetics.

Modifications of polysaccharide-based biomaterials under structure-property relationship for biomedical applications

Polysaccharides are well accepted biomaterials that have attracted considerable attention. Compared with other materials under research, polysaccharides show unique advantages: they are available in nature and are normally easily acquired, those acquired from nature show favorable immunogenicity, and are biodegradable and bioavailable. The bioactivity and possible applications are based on their chemical structure; however, naturally acquired polysaccharides sometimes have unwanted flaws that limit further applications. For this reason, carefully summarizing the possible modifications of polysaccharides to improve them is crucial. Structural modifications can not only provide polysaccharides with additional functional groups but also change their physicochemical properties. This review based on the structure-property relation summarizes the common chemical modifications of polysaccharides, the related bioactivity changes, possible functionalization methods, and major possible biomedical applications based on modified polysaccharides.

Development of Spirulina sea-weed raw extract/polyamidoamine hydrogel system as novel platform in photodynamic therapy: Photostability and photoactivity of chlorophyll a

The aim of this paper is to present and characterize Polyamidoamine-based hydrogels (PAA) as scaffolds to host photoactive Chlorophyll a (Chl a) from Spirulina (Arthrospira platensis) sea-weed Extract (SE), for potential applications in Photodynamic Therapy (PDT). The pigment extracted from SE was blended inside PAA without further purification, according to Green Chemistry principles. A comprehensive investigation of this hybrid platform, PAA/SE-based, was thus performed in our laboratory and, by means of Visible absorption and emission spectroscopies, the Chl a features, stability and photoactivity were studied. The obtained results evidenced the presence of two main Chl a forms, monomeric and dimeric, interacting with hydrogel polyamidoamines network. To better understand the nature of this interaction, the spectroscopic investigation of this system was performed both before and after the solidification of the hydrogel, that occurred at least in 24 h. Then, focusing the attention on solid scaffold, the ¹Chl a^⁎ fluorescence lifetime and FTIR-ATR analyses of PAA/SE were carried out, confirming the findings. The swelling and Point Zero Charge (PZC) measurements of solid PAA and PAA/SE were additionally performed to investigate the hydrogel behavior in water. Chl a molecules blended in PAA were (photo) stable and photoactive, and this latter feature was demonstrated showing that the pigment induced, when swelled in water and under irradiation, the formation of singlet oxygen (¹O₂), measured by direct and indirect methods.

Punica granatum as a Source of Natural Antioxidant and Antimicrobial Agent: A Comprehensive Review on Related Investigations

BACKGROUND

The consumption of natural antioxidants is increasing due to the demand and tendency to natural foods. Punica granatum L. [Punicaceae] is a fruit with various bioactive ingredients. The effectiveness of this plant has been proved against various disorders such as hyperglycemia, hyperlipidemia, blood coagulation, infections, cancer, and dentistry. Among them, there are numerous researches on antimicrobial and antioxidant properties. Subsequently, the present study aimed to compile a review of those properties to outline this herb as a possible natural antioxidant and preservative.

METHODS

Synchronically, keywords "Punica granatum" with antimicrobial, or antibacterial, antifungal, antiviral, antioxidant and radical scavenging were searched through "Scopus" database up to 31st September 2019. Papers focusing on agriculture, genetics, chemistry, and environmental sciences were excluded, and also related papers were collected.

RESULTS

Among 201 papers focusing on related activities, 111 papers have dealt with antioxidant activities focusing based on DPPH assay, 59 with antibacterial, on both gram+ and gram- bacteria, 24 with antifungal effects, mostly on Aspergillus niger and Candida albicans, and 7 papers with antiviral activities. There were about 50 papers focusing on in-vivo antioxidant activities of this plant.

CONCLUSION

Taken together, botanical parts of P. granatum have possessed notable radical scavenging and antimicrobial activities that, with these properties, this plant can be introduced as a natural, safe source of preservative and antioxidant. Accordingly, P. granatum can be applied as excipient with the aforementioned properties in the pharmaceutical and food industries.

Integrating biometallurgical recovery of metals with biogenic synthesis of nanoparticles

Industrial activities, such as mining, electroplating, cement production, and metallurgical operations, as well as manufacturing of plastics, fertilizers, pesticides, batteries, dyes or anticorrosive agents, can cause metal contamination in the surrounding environment. This is an acute problem due to the non-biodegradable nature of metal pollutants, their transformation into toxic and carcinogenic compounds, and bioaccumulation through the food chain. At the same time, platinum group metals and rare earth elements are of strong economic interest and their recovery is incentivized. Microbial interaction with metals or metals-bearing minerals can facilitate metals recovery in the form of nanoparticles. Metal nanoparticles are gaining increasing attention due to their unique characteristics and application as antimicrobial and antibiofilm agents, biocatalysts, in targeted drug delivery, for wastewater treatment, and in water electrolysis. Ideally, metal nanoparticles should be homogenous in shape and size, and not toxic to humans or the environment. Microbial synthesis of nanoparticles represents a safe, and environmentally friendly alternative to chemical and physical methods. In this review article, we mainly focus on metal and metal salts nanoparticles synthesized by various microorganisms, such as bacteria, fungi, microalgae, and yeasts, as well as their advantages in biomedical, health, and environmental applications.

Natural components in sunscreens: Topical formulations with sun protection factor (SPF)

Artificial sunscreens are already gaining traction in order to protect the skin from sunburns, photoaging and photocarcinogenesis. However, the efficacy and safety of most artificial sunscreen constituents are hindered by their photostability, toxicity and damage to marine ecosystems. Natural selection and evolution have ensured that plants and animals have developed effective protective mechanisms against the deleterious side effects of oxidative stress and ultraviolet radiation (UV). Hence, natural antioxidants such as sun blockers are drawing considerable attention. The exact mechanism by which natural components act as sunscreen molecules has not been clearly established. However, conjugated π system is reported to play an important role in protecting the vital genetic material within the organism. Compared to artificial sunscreens, natural sunscreens with strong UV absorptive capacities are largely limited by low specific extinction value and by their inability to spread in large-scale sunscreen cosmetic applications. Previous studies have documented that natural components exert their photoprotective effects (such as improved skin elasticity and hydration, skin texture, and wrinkles) through their antioxidant effects, and through the regulation of UV-induced skin inflammation, barrier impairment and aging. This review focuses on natural antioxidant topical formulations with sun protection factor (SPF). Lignin, melanin, silymarin and other ingredients have been added to high sun protection nature sunscreens without any physical or chemical UV filters. This paper also provides a reference for adopting novel technical measures (extracting high content components, changing the type of solution, optimizing formulation, applying Nano technology, et al) to design and prepare nature sunscreen formulations equated with commercial sunscreen formulations. Another strategy is to add natural antioxidants from plants, animals, microorganisms and marine organisms as special enhancer or modifier ingredients to reinforce SPF values. Although the photoprotective effects of natural components have been established, their deleterious side effects have not been elucidated.

Strategies to improve ellagic acid bioavailability: from natural or semisynthetic derivatives to nanotechnological approaches based on innovative carriers

Ellagic acid (EA) is a polyphenolic compound whose dietary consumption is mainly associated with the intake of red fruits, including pomegranates, strawberries, blackberries, blackcurrants, raspberries, grapes or dried fruits, like walnuts and almonds. A number of studies indicate that EA exerts health-beneficial effects against several chronic pathologies associated with oxidative damage, including different kinds of cancer, cardiovascular and neurodegenerative diseases. Furthermore, EA possesses wound-healing properties, antibacterial and antiviral effects, and acts as a systemic antioxidant. However, clinical applications of this polyphenol have been hampered and prevented by its poor water solubility (9.7 ± 3.2 μg ml^-1 in water) and pharmacokinetic profile (limited absorption rate and plasma half-life <1 h after ingestion of pomegranate juice), properties due to the chemical nature of the organic heterotetracyclic compound. Little has been reported on efficient strategies to enhance EA poor oral bioavailability, including chemical structure modifications, encapsulation within nano-microspheres to be used as carriers, and molecular dispersion in polymer matrices. In this review we summarize the experimental approaches investigated so far in order to improve EA pharmacokinetics, supporting the hypothesis that enhancement in EA solubility is a feasible route for increasing its oral absorption.

Chitosan-Ellagic Acid Nanohybrid for Mitigating Rotenone-induced Oxidative Stress

Antioxidants derived from nature, such as ellagic acid (EA), demonstrated high potency to mitigate neuronal oxidative stress and related pathologies, including Parkinson's disease. However, the application of EA is limited due to its toxicity at moderate doses and poor solubility, cellular permeability, and bioavailability. Here, we introduce a sustainably resourced, green nanoencasement strategy to overcome the limitations of EA and derive synergistic effects to prevent oxidative stress in neuronal cells. Chitosan, with its high biocompatibility, potential antioxidant properties, and flexible surface chemistry, was chosen as the primary component of the nanoencasement in which EA is immobilized. Using a rotenone model to mimic intracellular oxidative stress, we examined the effectiveness of EA and chitosan to limit cell death. Our studies indicate a synergistic effect between EA and chitosan in mitigating rotenone-induced reactive oxygen species death. Our analysis suggests that chitosan encapsulation of EA reduces the inherent cytotoxicity of the polyphenol (a known anticancer molecule). Furthermore, its encapsulation permits its delivery via a rapid burst phase and a relatively slow phase making the nanohybrid suitable for drug release over extended time periods.