Phytofabrication and Characterisation of Zinc Oxide Nanoparticles Using Pure Curcumin

Unbiased Metabolomic and Chemometric profiles of three Sargassum polycystum extracts using GCMS and LCMS/MS: content analysis, correlation analysis and molecular docking

Sargassum polycystum (S. polycystum) is a brown macroalga with a high phytochemical content, making it a nutritious and bioactive food source. However, information on factors contributing to health benefits, like antioxidants and cytotoxicity, is less explored for Malaysian S. polycystum. In this study, three extracts of S. polycystum were characterized using a combination of analytical techniques. Despite similar carbohydrate content across all extracts, water extract exhibited the highest protein [21.90 ± 1.01 albumin equivalent (μg/mg)] and phenolic [7.73 ± 1.95 gallic acid equivalent (μg/mg)] contents. However, it displayed the lowest antioxidant and anticancer activities [half-maximal inhibitory concentration (IC50) of > 2000 μg/mL]. Interestingly, ethanolic extract demonstrated the strongest scavenging activity (IC50 of 397.90 ± 20.43 μg/mL) and selective anticancer activity against MCF7 breast cancer cells (IC50 of 338.63 ± 48.98 μg/mL). Untargeted metabolomic profiling confirmed the differences in the chemical composition of the extracts. Subsequently, correlation and docking analyses were used to identify the potential bioactive compounds within the extracts. The ethanolic extract is a rich source of these bioactive compounds with superior antioxidant and anticancer properties, highlighting the need for further research on its potential utility in the food industry.

Extraction and characterization of sodium alginate from native Malaysian brown seaweed Sargassum polycystum

Malaysian seaweed, particularly Sargassum polycystum, has potential for alginate production, yet an extraction protocol for this seaweed remains lacking. This study aimed to optimize the extraction process to maximize alginate yield while characterizing the physicochemical properties of the extracted alginate and its potential applications. An alkali-based extraction method was employed, with key parameters, including alkali concentration, extraction temperature, and time, carefully optimized to yield 30.17 ± 0.76 % (g alginate/100 g dry seaweed biomass) of alginate. Sodium alginate extracted from Sargassum polycystum has a viscosity-average molecular weight of 4.73 ± 0.001 × 104 g/mol and an M/G ratio of 2.87. The physicochemical properties and biochemical composition of the extracted alginate revealed its capacity to be utilized as a natural antioxidant. An alginate-based nanohybrid for polyphenol delivery was developed to explore the potential applications of extracted alginate. This nanohybrid showed favorable properties (hydrodynamic particle size: 415 nm, PDI: 0.3, zeta potential: -44.7 mV), high encapsulation (80.13 %), and loading efficiency (19.21 ± 1.69 %). Alginate coating on the nanohybrid protected polyphenol from premature release, significantly enhancing its antioxidant activity. These findings suggest that alginate extracted from Malaysian Sargassum polycystum could be a valuable natural material for developing controlled-release delivery systems.

Advances in antibacterial activity of zinc oxide nanoparticles against Staphylococcus aureus (Review)

Nanoparticles (NPs) are one of the promising strategies to deal with bacterial infections. As the main subset of NPs, metal and metal oxide NPs show destructive power against bacteria by releasing metal ions, direct contact of cell membranes and antibiotic delivery. Recently, a number of researchers have focused on the antibacterial activity of zinc oxide nanoparticles (ZnO NPs) against Staphylococcus aureus (S. aureus). Currently, there is a lack of a comprehensive review on ZnO NPs against S. aureus. Therefore, in this review, the antibacterial activity against S. aureus of ZnO NPs made by various synthetic methods was summarized, particularly the green synthetic ZnO NPs. The synergistic antibacterial effect against S. aureus of ZnO NPs with antibiotics was also summarized. Furthermore, the present review also emphasized the enhanced activities against S. aureus of ZnO nanocomposites, nano-hybrids and functional ZnO NPs.

Clinacanthus nutans crude polysaccharide extract as a green platform for microwave-assisted synthesis of silver nanoparticles: Optimization, characterization, and evaluation of bioactivities

Clinacanthus nutans (C. nutans) is a plant in tropical Asia with proven biological activities. The optimized extraction method of C. nutans crude polysaccharide (CNP) uses water in the presence of an ultrasound-assisted mechanical method (UL_CNP). However, the use of UL_CNP for the synthesis and optimization of silver nanoparticles (AgNP), particularly their anticancer and photocatalytic properties, remains unexplored. Hence, this research aimed to employ a green method using UL_CNP and silver nitrate to produce AgNP (UL_AgNP) with a small size and assess its potential toxicity, anticancer, and photocatalytic activities. The synthesis condition was optimized using the Box-Behnken design method. The synthesized UL_AgNP showed the surface plasmon resonance peak at 458 nm. The optimized synthesis condition produced spherically shaped UL_AgNP with a size of 5.21 ± 1.92 nm and a zeta potential of -26.33 ± 0.93 mV. An X-ray diffraction analysis exhibited intense Bragg's reflection peaks at (111), (200), (220), and (311), having a face-centered cubic structure of AgNP. Attenuated total reflectance-Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy further confirmed the presence of silver in the synthesized UL_AgNP. The brine shrimp lethality test of UL_AgNP reported a lethal concentration 50 value of <7.8 μg/mL after 24 h. The UL_AgNP exhibited antiproliferative activity against MCF-7 cells with a half-maximal inhibitory concentration value of 4.96 ± 0.31 μg/mL by inducing S-phase cell cycle arrest, apoptotic effect, and reduction of cell migration. Furthermore, UL_AgNP proved its efficient photocatalytic activity against methylene blue dye (50.22 % ± 0.06 %, after 10 min at a concentration of 50 μg/mL). Therefore, the UL_AgNP exhibited promising antiproliferative activity against MCF-7 cells, highlighting their potential as a therapeutic agent. Further investigations are needed to elucidate the precise mechanism of their action.

Exploring the potential of a Ephedra alata leaf extract: Phytochemical analysis, antioxidant activity, antibacterial properties, and green synthesis of ZnO nanoparticles for photocatalytic degradation of methylene blue

Ephedra alata leaf extracts have therapeutic properties and contain various natural compounds known as phytochemicals. This study assessed the phytochemical content and antioxidant effects of a Ephedra alata leaf extract, as well as zinc oxide (ZnO) nanoparticle production. The extract contained phenolic acids, including vanillic acid, chlorogenic acid, gallic acid, p-coumaric acid, vanillin and rutin. Its total phenolic content and total flavonoid content were 48.7 ± 0.9 mg.g-1 and 1.7 ± 0.4 mg.g-1, respectively. The extract displayed a DPPH inhibition rate of 70.5%, total antioxidant activity of 49.5 ± 3.4 mg.g-1, and significant antimicrobial activity toward Gram-positive and negative bacteria. The synthesized ZnO nanoparticles had spherical shape, crystallite size of 25 nm, particle size between 5 and 30 nm, and bandgap energy of 3.3 eV. In specific conditions (90 min contact time, pH 7, and 25°C), these nanoparticles efficiently photodegraded 87% of methylene blue, suggesting potential applications for sustainable water treatment and pollution control.

Facile one-pot hydrothermal synthesis of a zinc oxide/curcumin nanocomposite with enhanced toxic activity against breast cancer cells

Zinc oxide/Curcumin (Zn(CUR)O) nanocomposites were prepared via hydrothermal treatment of Zn(NO3)2 in the presence of hexamethylenetetramine as a stabilizing agent and CUR as a bioactive element. Three ZnO : CUR ratios were investigated, namely 57 : 43 (Zn(CUR)O-A), 60 : 40 (Zn(CUR)O-B) and 81 : 19 (Zn(CUR)O-C), as assessed by thermogravimetric analyses, with an average hydrodynamic diameter of nanoaggregates in the range of 223 to 361 nm. The interaction of CUR with ZnO via hydroxyl and ketoenol groups (as proved by X-ray photoelectron spectroscopy analyses) was found to significantly modify the key properties of ZnO nanoparticles with the obtainment of a bilobed shape (as shown by scanning electron microscopy), and influenced the growth process of the composite nanoparticles as indicated by the varying particle sizes determined by powder X-ray diffraction. The efficacy of Zn(CUR)O as anticancer agents was evaluated on MCF-7 and MDA-MB-231 cancer cells, obtaining a synergistic activity with a cell viability depending on the CUR amount within the nanocomposite. Finally, the determination of reactive oxygen species production in the presence of Zn(CUR)O was used as a preliminary evaluation of the mechanism of action of the nanocomposites.