Nanotechnology can offer a series of new “green” and eco-friendly methods for developing different types of nanoparticles, among which the development of nanomaterials using plant extracts (phytosynthesis) represents one of the most promising areas of research. This present study details the use of lavender flowers (Lavandula angustifolia Mill., well-known for their use in homeopathic applications) for the biosynthesis of silver nanoparticles with enhanced antioxidant and antibacterial properties. Several qualitative and quantitative assays were carried out in order to offer an image of the extracts’ composition (the recorded total phenolics content varied between 21.0 to 40.9 mg GAE (gallic acid equivalents)/g dry weight (d.w.), while the total flavonoids content ranged between 3.57 and 16.8 mg CE (catechin equivalents)/g d.w.), alongside modern analytical methods (such as gas chromatography-mass spectrometry—GC-MS, quantifying 12 phytoconstituents present in the extracts). The formation of silver nanoparticles (AgNPs) using lavender extract was studied by UV-Vis spectroscopy, Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS)/zeta potential, with the selected nanoparticles having crystallite sizes of approx. 14.55 nm (AgNP-L2) and 4.61 nm, respectively (for AgNP-L4), and hydrodynamic diameters of 392.4 nm (for AgNP-L2) and 391.6 nm (for AgNP-L4), determined by DLS. A zeta potential of around −6.4 mV was displayed for both samples while presenting as large aggregates, in which nanoparticle clusters with dimensions of around 130–200 nm can be observed. The biomedical applications of the extracts and the corresponding phytosynthesized nanoparticles were evaluated using antioxidant and antimicrobial assays. The obtained results confirmed the phytosynthesis of the silver nanoparticles using Lavandula angustifolia Mill. extracts, as well as their antioxidant and antimicrobial potential.
Pumpkin (Cucurbita maxima) is a fruit packed with vitamins and nutrients beneficial to human health with numerous therapeutic uses including antiparasitic, antioxidant, it helps to lower bad cholesterol, as an adjuvant in weight loss, improves cancer prevention, etc. Pumpkin is rich in beta-carotene, and contains significant amounts of lutein and zeaxanthin, antioxidants that can considerably prevent cataracts and macular degeneration. Worldwide, five pumpkin species are grown for their edible fruit and seeds. This paper describes the qualitative screening of phytocompounds and the quantitative determination of the main bioactive compounds found in two pumpkin species: Valenciano and Waltham Butternut. The qualitative screening of phytochemicals was based on the visual change in color of aqueous extracts upon adding known reactants. This allowed a preliminary evaluation regarding the presence of different bioactive compounds such as saponins, alkaloids, tannins, flavonoids, etc. In order to determine the specific amount of different phytocompounds (e.g., total content of polyphenols, total content of flavonoids, etc.) UV-Vis spectra were recorded in triplicate at well-established wavelengths, thus obtaining an average absorbance. For example, a method widely applied for the determination of total polyphenolic content is the Folin–Ciocalteu (FC) reaction, which is basically an antioxidant analyses that relies on electron transfer that measures the reductive ability of a specific antioxidant. Briefly, the FC reaction involved mixing 1 mL diluted aqueous extract with 5 mL FC reagent and adding 4 mL Na2CO3 after 8 min After 60 min incubation at room temperature, we recorded the absorptions at 765 nm, which corresponds to the gallic acid curve calibration standard. Also, the antioxidant activity was recorded by using the DPPH method for both aqueous extracts.
Silver nanoparticles, widely known for their antimicrobial, antioxidant, and antifungal properties, can be obtained using conventional or unconventional methods and have various applications in different scientific fields, including degradation of dyes from the textile industry [1,2].
Introduction: Silver nanoparticles (AgNPs), widely recognized for their antimicrobial and antioxidant capacity, can be prepared following both conventional and unconventional routes and have a multitude of applications in numerous scientific domains, including the catalytic degradation of dyes that result from the textile industry