Eco-friendly synthesis of size-controlled silver nanoparticles by using Areca catechu nut aqueous extract and investigation of their potent antioxidant and anti-bacterial activities

Silver nanoparticles (AgNPs) have attracted considerable attention owing to their unique biological applications. AgNPs synthesized by plant extract is considered as a convenient, efficient and eco-friendly material. In this work, the aqueous extract of Areca catechu L. nut (ACN) was used as the reducing and capping agents for one-pot synthesis of AgNPs, and their antioxidant and antibacterial activities were investigated. UV (Ultra Violet)-visible spectrum and dynamic light scattering (DLS) analysis revealed that the size of AgNPs was sensitive to the synthesis conditions. The synthesized AgNPs were composed of well-dispersed particles with an small size of about 10 nm under the optimal conditions (pH value of extract was 12.0; AgNO₃ concentration was 1.0 mM; reaction time was 90 min). In addition, scanning electron microscope with energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD) results further verified that the synthesized AgNPs had a stable and well-dispersed form (Zeta potential value of ?30.50 mV and polydispersity index of 0.328) and a regular spherical shape (average size of 15–20 nm). In addition, Fourier transform infrared spectrometry (FTIR) results revealed that phytochemical constituents in ACN aqueous extract accounted for Ag⁺ ion reduction, capping and stabilization of AgNPs. The possible reductants in the aqueous extract of Areca catechu L. nut were identified by high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (HPLC-ESI-qTOF/MS) method. More importantly, the synthesized AgNPs indicated excellent free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH, IC₅₀ = 11.75 ± 0.29 μg/mL) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS⁺, IC₅₀ = 44.85 ± 0.37 μg/mL), which were significant higher than that of ascorbic acid. Moreover, AgNPs exhibited an enhanced antibacterial activity against six selected common pathogens (especially Escherichia coli and Staphylococcus aureus) compared with AgNO₃ solution. In a short, this study showed that the Areca catechu L. nut aqueous extract could be applied for eco-friendly synthesis of AgNPs.     

Rutin induces endoplasmic reticulum stress-associated apoptosis in human triple-negative breast carcinoma MDA-MB-231 cells – In vitro and in silico docking studies

Rutin is a bioactive compound that possesses anti-tumor activities through triggering apoptosis. Triple-negative breast cancer (TNBC) is insensitive to targeted anti-tumoral drugs, and drug resistance in TNBC poses a challenge for a successful cure. The accumulation of misfolded proteins in the lumen of the endoplasmic reticulum (ER) results in cellular stress that initiates a specialized response designated as the unfolded protein response. This study aimed to find potential ER stress targets in triple-negative breast cancer. The viability of cells was evaluated using an MTT assay. Cell migration and proliferation were done by wound scratch and colony formation assay. Cell cycle detection, measurement of ER stress, mitochondrial membrane potential disruption, and cell death identification was performed using flow cytometry. The interaction of rutin with ER stress proteins is predicted using in silico docking. The pattern of gene expression was determined by qRT-PCR. The elevated rate of cell viability, cell cycle arrest, ER stress, MMP, and apoptotic induction was observed in combination treatment. Rutin exhibited the highest glide score with ASK1 and JNK. The results of qRT-PCR showed that rutin induced apoptosis through upregulation of ASK1 and JNK. The present study provides strong evidence supporting an important role of the ER stress response in mediating rutin-induced apoptosis in triple-negative breast cancer.     

Progress on phthalocyanine-conjugated Ag and Au nanoparticles: Synthesis,characterization, and photo-physicochemical properties

Phthalocyanine (Pc) complexes are an important class of dyes with numerous (e.g., biological, photophysical, and analytical) applications. Among the methods used to improve the properties of these complexes, one should mention the introduction of different substituents, variation of the central metal ion, ligand exchange, and conjugation to nanomaterials (e.g., carbon-based nanomaterials and metal nanoparticles (NPs)). This work briefly reviews Pc complex conjugation to Ag and Au NPs, highlights the different NP shapes, and discusses the diversity of conjugation approaches. Moreover, the use of UV–Vis spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopy to characterize Pc-NP hybrids is summarized. The effect of conjugation on Pc photo-physicochemical properties (fluorescence, singlet oxygen generation, triplet state formation, and optical limiting behavior) is discussed, and future perspectives for the synthesis and applications of new hybrids are provided.     

Ascorbic acid supported Carboxymethyl cellulose stabilized silver nanoparticles as optical nanoprobe for Au3+ detection in environmental sample

Heavy metals (HMs), pollution of major environmental matrices and its attendant effects on human health and the environment, continue to generate huge scientific interest, particularly in monitoring and detection. Herein, the optical property of carboxymethyl cellulose stabilized silver nanoparticles (CMC-AgNPs), supported with ascorbic acid, is exploited as a colorimetric probe for the detection of toxic Au³⁺ ion in solution. The as-synthesized CMC-AgNPs showed sharp absorption maximum at 403 nm, with sparkling yellow color and average particles size distribution less than 10 nm. It was further characterized using ATR-FTIR, TEM, FESEM/EDS, XRD and DLS/zeta potential analyzer. Au³⁺ ion detection strategy involves the addition of ascorbic acid (AA) to a pH adjusted CMC-AgNPs, followed by the analyte addition. AA would facilitate the reduction of Au³⁺ on CMC-AgNPs (seed), with resultant color perturbations from light yellow to yellow, orange, ruby red and purple red, under 8 min incubation, at room temperature (RT). The CMC-AgNPs could also serve as a catalyst, by promoting AA mediated reduction of Au³⁺, in-situ. Moreover, we propose, that the color and the absorption spectra change is attributed to the deposition of gold nanoparticles (AuNPs), on the CMC-AgNPs/AA probe, to form (CMC-Ag@Au) nanostructures, depending on the analyte concentration. Absorbance ratio (A₅₄₀/A₄₀₃) showed good linearity with Au³⁺ concentration from 0.25 to 100.0 µM, and an estimated LOD of 0.061 µM. The assay was applied to Au³⁺ detection in environmental wastewater sample, showing satisfactory real sample detection potentiality.     

Biosynthesis of silver and gold nanoparticles using Sargassum horneri extract as catalyst for industrial dye degradation

This study focuses on the green synthesis of silver and gold nanoparticles using the marine algae extract, Sargassum horneri, as well as the degradation of organic dyes using biosynthesized nanoparticles as catalysts. The phytochemicals of the brown algae Sargassum horneri acted as reducing and capping agents for nanoparticle synthesis. Ultraviolet–visible absorption spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy were used to characterize the biosynthesized nanoparticles. The green-synthesized SH-AgNPs and SH-AuNPs exhibited high catalytic activity for degradation of organic dyes, such as methylene blue, rhodamine B, and methyl orange. The reduction reactions of dyes are based on pseudo-first-order kinetics.     

Enhanced skin anti-inflammatory and moisturizing action of gold nanoparticles produced utilizing Diospyros kaki fruit extracts

Inflammatory skin diseases (ISD) cause very severe itchy skin and dryness which is now a days an important issue which has to be taken care. Nanotechnology plays a main role in manufacturing cosmetic ingredients at a nanoscale size. Among different nanoparticles, gold (Au) is one of the non-toxic materials synthesized organically or inorganically. For synthesizing nanoparticles (NPs), using inorganic methods may cause some toxicity to cells, but using organic synthesis like plant extract is less toxic and environmentally friendly. Therefore, we synthesized DK-AuNPs using Diospyros kaki fruit extract. UPLC-MS/MS was used to evaluate phytochemicals responsible for converting salt into nanoparticles. The DK-AuNPs were characterized to confirm the formation of NPs. Furthermore, we analyzed the activity of DK-AuNPs on human keratinocytes (HaCaT cells). The DK-AuNPs showed 98.2 % cell survival upto 200 µg/mL against HaCaT cells. Additionally, compared to DK treatment, DK-AuNPs therapy decreased ROS production in TNF-α/IFN-γ (T + I) stimulated HaCaT cells by 68.7 %, whereas DK treatment reduced ROS generation by 27.8 %. Moreover, the skin anti-inflammatory potential and moisturizing effect of DK-AuNPs were analyzed using HaCaT cells. Furthermore, skin inflammatory activity biomarkers were downregulated through the MAPK/NFκB signaling pathway and showed significant inhibition by DK-AuNPs. Also, the skin moisturizing biomarkers such as HAS (1–3) were upregulated and HYAL (1–2) were downregulated by PI3K/AKT/NFκB through HAS2 regulation. Therefore, skin anti-inflammatory and moisturizing activity were enhanced by treatment with DK-AuNPs. In summary, we conclude that the DK-AuNPs could be a new alternative for skin disease.     

Choline chloride – Urea deep eutectic solvent an efficient media for the preparation of metal nanoparticles

Metal nanoparticles are nanosized structures that have different potential applications in biological, chemical, medical, and agricultural fields because of their exotic characteristics. Their size ranges from 1 to 100 nm. Metal nanoparticles are either purer forms of metals (eg: Gold, Silver, Copper, Iron, etc.) or their compounds (eg: sulfides, hydroxides, oxides, etc.). Ionic liquids are generally used in the extraction of nanoparticles but they are challenging because of their indigent bio-degradability, bio-compatibility, and sustainability. So Deep Eutectic Solvent (DES) is reported as an alternative to ionic liquids in the formation of nanoparticles. The DESs are a complex of quaternary ammonium salts and hydrogen donors or metal salt. DESs contain higher non-symmetric ions which have lower lattice energy and hence they have a lower melting point. This research utilizes a novel DES (choline chloride – urea) as an effective solvent to produce mercuric sulfide (HgS), zirconium oxide (ZrO), manganese oxide (MnO), and copper oxide (CuO) nanoparticles. As a result, the production of these metal nanoparticles using Choline Chloride (C₅H₁₄ClNO) – Urea DES can be treated as a promising way in chemical manufacturing. The nanoparticles have been analyzed using Ultra Violet Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Analysis (EDAX).     

Pentacyclic Triterpenoids,Phytosteroids and Fatty Acid Isolated from the Stem-bark of Cola lateritia K. Schum. (Sterculiaceae) of Cameroon origin; Evaluation of Their Antibacterial Activity

The phytochemical investigation on the chemical constituents of dichloromethane-methanol (1:1) stem-bark extract of Cola lateritia K. Schum. (Sterculiaceae) led to the isolation and characterization of five pentacyclic triterpenoids, one fatty acid and two phytosteroids. The compounds were identified as heptadecanoic acid (1), maslinic acid (2), betulinic acid (3), lupenone (4), lupeol (5), friedelin (6), β-stigmasterol (7) and ß-sitosterol-3-O-ß-D-glucoside (8). Their structures were determined by NMR analysis (¹H, ¹³C, DEPT-135, COSY, HMBC and HSQC), high-resolution mass spectrometry (HR-ESI-MS) and comparisons with published data in the literature. This work, to the best of our knowledge, is the first isolation and identification of these compounds in pure forms from Cola lateritia. Also, compounds 1–3 are reported for the first time from Cola genus. In vitro antibacterial activity of the isolated compounds (1–8) and the crude extract were evaluated against Bacillus subtilis, Staphylococcus epidermidis, Enterococcus faecalis, Mycobacterium smegmatis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Proteus vulgaris, Klebsiella pneumonia, Escherichia coli, Proteus mirabilis and Klebsiella aerogenes with streptomycin, nalidixic acid and ampicillin as standard antibacterial drugs. Compound 2 was active against E. faecalis (MIC = 18.5 µg/mL), and it was 6.9 and 28 times lower and active than that of streptomycin (MIC 128 µg/mL) and nalidixic acid (MIC > 512 µg/mL) respectively. All the isolated compounds and crude extract showed significant activities against the tested bacterial strains.     

Dynamic variations of bioactive compounds driven by enzymes in Psoralea corylifolia L. from growth to storage and processing

Fructus Psoraleae (FP), the dried ripe fruit of Psoralea corylifolia L., is a popular herbal medicine commonly applied for alleviating osteoporosis and vitiligo. But, until now, the dynamic variations of compounds in P. corylifolia have been less investigated during its growth, storage, and treatment by different temperatures, which is meaningful for guaranteeing the quality of FP. In this study, focused on these questions, with emphasis on the enzyme-driven dynamic transformation of coumarins, ultra-high performance liquid chromatography coupled with photodiode array detector (UHPLC-PDA) method was successfully established for the simultaneous determination of nine compounds. The distribution and accumulation of compounds were discussed and illuminated in different parts of P. corylifolia and samples harvested at different times. The characteristics of compounds' variation in flowers and fruits of P. corylifolia were identified. Through the market survey and quantitative study on FP, positive correlation was speculated between transformation from (iso)psoralenoside to (iso)psoralen via β-glucosidase and storage time, which was further confirmed by accelerated stability test. The effect of treated temperatures (40–210 °C) was unveiled on the enzyme activity and transformation from (iso)psoralenoside to (iso)psoralen in FP. And the focused compounds' transformation was mainly driven by β-glucosidase when the temperature was below 120 °C. Above 120 °C, β-glucosidase was completely inactivated, and the focused compounds' transformation was mediated by high-temperature, also the obvious degradation was found. Our results demonstrated that compounds' transformation characteristics arising from the growth, processing and storage of P. corylifolia are critical factors to ensure the quality of FP.     

Application of HPLC to measure vanadium in environmental,biological and clinical matrices

Vanadate and vanadium compounds exist in many environmental, biological and clinical matrices, and despite the need only limited progress has been made on the analysis of vanadium compounds. The vanadium coordination chemistry of different oxidation states is known, and the result of the characterization and speciation analysis depends on the subsequent chemistry and the methods of analysis. Many studies have used a range of methods for the characterization and determination of metal ions in a variety of materials. One successful technique is high performance liquid chromatography (HPLC) that has been used mainly for measuring total vanadium level and metal speciation. Some cases have been reported where complexes of different oxidation states of vanadium have been separated by HPLC. Specifically reversed phase (RP) HPLC has frequently been used for the measurement of vanadium. Other HPLC methods such as normal phase, anion-exchange, cation-exchange, size exclusion and other RP-HPLC modes such as, ion-pair and micellar have been used to separate selected vanadium compounds. We will present a review that summarizes and critically analyzes the reported methods for analysis of vanadium salts and vanadium compounds in different sample matrices. We will compare various HPLC methods and modes including sample preparation, chelating reagents, mobile phase and detection methods. The comparison will allow us to identify the best analytical HPLC method and mode for measuring vanadium levels and what information such methods provide with regard to speciation and quantitation of the vanadium compounds.     

Camellia sinensis: Insights on its molecular mechanisms of action towards nutraceutical,anticancer potential and other therapeutic applications

The Camellia sinensis plant provides a wide diversity of black, green, oolong, yellow, brick dark, and white tea. Tea is one of the majorly used beverages across the globe, succeeds only in the water for fitness and pleasure. Generally, green tea has been preferred more as compared to other teas due to its main constituent e.g. polyphenols which contribute to various health benefits. The aim of this updated and comprehensive review is to bring together the latest data on the phytochemistry and pharmacological properties of Camellia sinensis and to highlight the therapeutic prospects of the bioactive compounds in this plant so that the full medicinal potential of Camellia sinensis can be realised. A review of published studies on this topic was performed by searching PubMed/MedLine, Scopus, Google scholar, and Web of Science databases from 1999 to 2022. The results of the analysed studies showed that the main polyphenols of tea are the four prime flavonoids catechins: epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC) along with the beneficial biological properties of tea for a broad heterogeneity of disorders, including anticancer, neuroprotective, antibacterial, antiviral, antifungal, antiobesity, antidiabetes and antiglaucoma activities. Poor absorption and low bioavailability of bioactive compounds from Camellia sinensis are limiting aspects of their therapeutic use. More human clinical studies and approaching the latest nanoformulation techniques in nanoparticles to transport the target phytochemical compounds to increase therapeutic efficacy are needed in the future.     

Enhanced rheological properties and performance of viscoelastic surfactant fluids with embedded nanoparticles

A combination of viscoelastic surfactants with nanoparticles gives a new class of functional self-assembled materials promising for a large variety of applications. Nanoparticles improve the rheological properties of these systems because of the incorporation into the network of entangled wormlike micelles by linking to micellar end-caps, thus leading to elongation or cross-linking of the micelles. The present article reviews recent studies of these hybrid systems. Mechanisms of the interaction of nanoparticles with wormlike surfactant micelles as well as factors favoring the enhancement of rheological properties of viscoelastic surfactants by added nanoparticles are discussed, providing ways for proper design of such systems in the future. It is shown that viscoelastic surfactants modified with nanoparticles display very attractive features for practical applications, in particular, for fracturing fluids in oil recovery.     

Phytogenic fabrication of iron oxide nanoparticles and evaluation of their in vitro antibacterial and cytotoxic activity

Several metal-based nanoparticles (NPs) have been found to be toxic and are known to exert adverse health outcomes with irreversible side effects. This highlights the need to discover effective, stable, and biocompatible therapeutic components using natural sources. Here, a hexane extract of Nigella sativa seeds was used to synthesize iron oxide NPs (NS-IONPs) embedded with N. sativa phytoconstituents. The extract acted as a reducing agent that restricted the size of the NS-IONPs to 5–6 nm, signifying the potential to be cleared through the renal system. The fabricated NS-IONPs had a prominent effect on pathogenic gram-negative bacteria, E. coli (19.3 mm) and Salmonella typhi (14.2 mm) and lung cancer cells (lowest IC₅₀ of 18.75 µg/mL) mainly by binding to the phospholipid components of the cell membrane. This resulted in cell shrinkage and further inhibited cell growth. Transmission electron microscopy analyses revealed that the mechanisms of cellular NP uptake varied depending on the cell type. Accumulation of NS-IONPs inside the cell increased BAX expression and arrested the cells at the G0/G1 phase, thereby conspicuously extending the G0 phase to initiate necrosis. Thus, these finding suggest that the synthesized NS-IONPs exhibited high antibacterial activity and effective cytotoxicity against cancer cell lines A549 and HCT116 compared to IONPs. The innovation of the current study is that the biogenic fabrication of IONPs is simple and cost effective results in stable nanomaterial, NS-IONPs with potential antibacterial and anticancer activity, which can be explored furthermore for various biomedical applications.     

Preparation of carbon-aerogel polypyrrole composite for desalination by hybrid capacitive desalination method

Capacitive Deionization (CDI) is an emerging technology with great potential applications. Most researchers view it as a viable water treatment alternative to reverse osmosis. This research reports the preparation and application of a carbon aerogel polypyrrole (CA-PPy) composite for the desalination of NaCl solution by the hybrid CDI method. The carbon aerogel (CA) was prepared from a Resorcinol / Formaldehyde precursor by the sol–gel method. The aerogel obtained from the sol–gel was then pyrolysed in a tube furnace to form CA. Polypyrrole (PPy) was prepared by the Oxidative chemical polymerisation of pyrrole, ferric chloride hexahydrate (oxidant), and sodium dodecyl sulfate (dopant). A composite of CA and PPy was then prepared and used to modify carbon electrodes. The CA-PPy composite was characterised to verify its composition, morphology, thermal properties, and functional groups. The electrochemical properties of the material were determined by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) tests. The electrochemical tests were done using a GAMRY potentiostat electrochemical workstation, a 1.0 M KCl was used as the electrolyte, and the applied potential window was (-0.2 to + 0.6) V for the CV test. The EIS test was done with the same concentration of KCl electrolyte at an applied potential of 0.22 V and at a frequency range of (0.1 – 100, 000) Hz. The optimal specific capacitance of the CA is 115F/g, and that of the composite is 360.1F/g, they were both obtained at a scan rate of 5 mV/s. The CDI desalination study of the CA-PPy composite showed a salt adsorption capacity (SAC) of 10.10 mg/g (300 mg/L NaCl solution) – 15.7 mg/g (800 mg/L NaCl solution) at 1.2 V applied voltage. The salt recovery efficiency of the electrode material in the 300 mg/L solution is 27 %, in the 500 mg/L solution, it is 20.12 %, and in the 800 mg/L solution, it is 15.41 %. The electrode material also showed good electrochemical stability after nine cycles of ion adsorption/desorption study.     

Preparation and characterization of a novel magnetized nanosphere as a carrier system for drug delivery using Plantago ovata Forssk. hydrogel combined with mefenamic acid as the drug model

The aim of the present study was to magnetize Plantago ovata Forssk. hydrogel and produce a nanosphere system to carrier mefenamic acid as the drug model. For this propose, P. ovata seeds hydrogel (POSH) was extracted and magnetized by Fe₃O₄ being functionalized using tetraethyl orthosilicate and trimethoxyvinysilane. Thereafter, mefenamic acid (MFA) was loaded on the carrier system. The final product, as the magnetic drug loaded nanosphere (Fe/POSH/MFA), was fully characterized through different techniques involving X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating-sample magnetometer (VSM), thermal gravimetric analysis (TGA), dynamic light scattering (DLS), and FT-IR spectroscopy. The results confirmed the successful production of the drug loaded nanosphere system with particles magnetization of 25 emu/g over a range size of 40–50 nm. However, the size distribution less than 100 nm was measured through DLS analysis. The hydrogel showed a pH sensitivity swelling behavior representing the best efficacy at pH 7.4. The efficiency of the drug encapsulation was found to be 64.35%. The drug releasing was studied using a dialysis bag at pH = 7.4. The highest in vitro drug releasing was found to be 57.3 ± 0.6% after 72 h, as well. The findings of the current report account for the potential use of P. ovata hydrogel as an effective delivery system for encapsulation of water insoluble basic drugs, e.g., MFA in a magnetized carrier system.     

Integrating approach to discover novel bergenin derivatives and phenolics with antioxidant and anti-inflammatory activities from bio-active fraction of Syzygium brachythyrsum

Syzygium brachythyrsum is an important folk medicinal and edible plant in Yunnan ethnic minority community of China, however, little is known about the chemical and bio-active properties. The present study is aimed to identify the bioactive constituents with antioxidant and anti-inflammatory properties by an integrating approach. First, two new bergenin derivatives, brachythol A (1) and brachythol B (2), together with eleven known phenolic compounds (3–13) were isolated from bioactive fractions by phytochemical method. Among these isolated chemicals, five bergenin derivatives, along with 3 phenolics were found in Syzygium genus for the first time. Then, a further chemical investigation based on ultra-high-performance liquid chromatography-Q Exactive Orbitrap mass spectrometry resulted in a total of 107 compounds characterized in the bio-active fractions, including 50 bergenin derivatives, among which 14 bergenin derivatives and 14 phenolics were potential new natural chemicals. Most of the isolated compounds showed obvious antioxidant activities, while compounds 11, 12, and 13 had favorable performance. Eight compounds (2–5, 7, and 9–11) showed good inhibitory activity on nitric oxide (NO) production in macrophage RAW 264.7 cells. The structure–activity correlation analysis indicated that the antioxidation and anti-inflammatory activities enhanced when bergenin was esterified with gallic acid, caffeic acid or ferulic acid. This is the first report of bergenins in Syzygium genus and the richness in new bio-active bergenins and gallic acid derivatives indicated that Syzygium brachythyrsum is a promising functional and medicinal resource.     

Production of bioactive compounds from callus of Pueraria thomsonii Benth with promising cytotoxic and antibacterial activities

For thousands of years Pueraria thomsonii Benth has been used to treat a number of diseases in traditional Chinese pharmacopeia. Despite these uses, there is still insufficient information on its biological activity and chemical composition. In this respect, the in vitro callus culture of P. thomsonii was subjected to identify anticancer and antibacterial compounds. Based on significant preliminary cytotoxicity and antibacterial activities; the chemical investigation led to the isolation of isoflavonoids, coumaric acid derivative and dihydroxyflavanone-type of compounds viz., daidzin (1), puerarin (2), biochanin A (3), daidzein (4), p-coumaric acid ethyl ester (5) and liquiritigenin (6), respectively. These compounds were tested for their cytotoxicity and antibacterial activities. Among them, p-coumaric acid ethyl ester (5) exhibited significant cytotoxicity with GI₅₀ values of 14.73, 15.64 and 20.88 μM/mL against 4T1, NC1-H1975 and A549, respectively; the other isoflavones and aflavonoid showed moderate to weak activities. Moreover, p-coumaric acid ethyl ester (5) inhibited the growth of K. pneumonia, MRSE and MRSA at very low MIC values of 6.01, 12.01 µg/mL 24.02, respectively. On the other hand compounds biochanin A (3) and liquiritigenin (6) showed moderate antibacterial activity. Because of the potential anticancer and antibacterial activities of bioactive compounds from P. thomsonii, they can be used to treat various cancer and emerging bacterial infections.     

Insights into recent advances of chitosan-based adsorbents for sustainable removal of heavy metals and anions

With globally increased human population and industrialization, the natural sources of water are reduced and then contaminated. Therefore, development of advanced technologies for the efficient water treatment is becoming of the scope of each of the nation. One of the cost-effective and well-known technologies for wastewater treatment is adsorption of contaminants by natural biopolymer like chitosan (CS) due to its unique features such as availability, biodegradability, biocompatibility, eco-friendly and low-cost production. However, Cs suffers considerable limitations such as low adsorption capacity, low surface area and limited reusability. Thence, this review intended to provide an overview for recent advances of chitosan-based adsorbents that established better adsorption activities towards various hazard heavy metals, including: As(III), As(V), Cu(II), Cr(VI), Pb(II) and Cd(II) ions. In addition, the capabilities of chitosan-based adsorbents for the adsorptive removal of anions including phosphates and nitrates were discussed. Besides, the suggested adsorption mechanisms of these contaminants onto chitosan-based adsorbents and the research conclusions for the optimum conditions of the adsorption processes were explained in light of the currently reported studies. Furthermore, to emphasize the foremost research gaps and future potential trends that could inspire further researchers to find out the best solutions for water treatment problems.     

Efficient synthesis of magnetic nanoparticle-Musa acuminata peel composite for the adsorption of anionic dye

The impregnation of magnetite (Mt) nanoparticle (NPs) onto Musa acuminata peel (MApe), to form a novel magnetic combo (MApe-Mt) for the adsorption of anionic bromophenol blue (BPB) was studied. The SEM, EDX, BET, XRD, FTIR and TGA were used to characterize the adsorbents. The FTIR showed that the OH and CO groups were the major sites for BPB uptake onto the adsorbent materials. The average Mt crystalline size on MApe-Mt was 21.13 nm. SEM analysis revealed that Mt NPs were agglomerated on the surface of the MApe biosorbent, with an average Mt diameter of 25.97 nm. After Mt impregnation, a decrease in BET surface area (14.89 to 3.80 m²/g) and an increase in pore diameter (2.25–3.11 nm), pore volume (0.0052–0.01418 cm³/g) and pH point of zero charge (6.4–7.2) was obtained. The presence of Pb(II) ions in solution significantly decreased the uptake of BPB onto both MApe (66.1–43.8%) and MApe-Mt (80.3–59.1%), compared to other competing ions (Zn(II), Cd(II), Ni(II)) in the solution. Isotherm modeling showed that the Freundlich model best fitted the adsorption data (R² > 0.994 and SSE < 0.0013). In addition, maximum monolayer uptake was enhanced from 6.04 to 8.12 mg/g after Mt impregnation. Kinetics were well described by the pseudo-first order and liquid film diffusion models. Thermodynamics revealed a physical, endothermic adsorption of BPB onto the adsorbents, with ΔH^o values of 15.87–16.49 kJ/mol, corroborated by high desorption (over 90%) of BPB from the loaded materials. The viability of the prepared adsorbents was also revealed in its reusability for BPB uptake.     

Pharmacophore model-aided virtual screening combined with comparative molecular docking and molecular dynamics for identification of marine natural products as SARS-CoV-2 papain-like protease inhibitors

Targeting SARS-CoV-2 papain-like protease using inhibitors is a suitable approach for inhibition of virus replication and dysregulation of host anti-viral immunity. Engaging all five binding sites far from the catalytic site of PLpro is essential for developing a potent inhibitor. We developed and validated a structure-based pharmacophore model with 9 features of a potent PLpro inhibitor. The pharmacophore model-aided virtual screening of the comprehensive marine natural product database predicted 66 initial hits. This hit library was downsized by filtration through a molecular weight filter of ≤ 500 g/mol. The 50 resultant hits were screened by comparative molecular docking using AutoDock and AutoDock Vina. Comparative molecular docking enables benchmarking docking and relieves the disparities in the search and scoring functions of docking engines. Both docking engines retrieved 3 same compounds at different positions in the top 1 % rank, hence consensus scoring was applied, through which CMNPD28766, aspergillipeptide F emerged as the best PLpro inhibitor. Aspergillipeptide F topped the 50-hit library with a pharmacophore-fit score of 75.916. Favorable binding interactions were predicted between aspergillipeptide F and PLpro similar to the native ligand XR8-24. Aspergillipeptide F was able to engage all the 5 binding sites including the newly discovered BL2 groove, site V. Molecular dynamics for quantification of Cα-atom movements of PLpro after ligand binding indicated that it exhibits highly correlated domain movements contributing to the low free energy of binding and a stable conformation. Thus, aspergillipeptide F is a promising candidate for pharmaceutical and clinical development as a potent SARS-CoV-2 PLpro inhibitor.