In this work, the hexane, chloroform, and methanol extracts from Kalanchoe fedtschenkoi were utilized to green-synthesize silver nanoparticles (Kf₁-, Kf₂-, and Kf₃-AgNPs). The Kf₁-, Kf₂-, and Kf₃-AgNPs were characterized by spectroscopy and microscopy techniques. The antibacterial activity of AgNPs was studied against bacteria strains, utilizing the microdilution assay. The DPPH and H₂O₂ assays were considered to assess the antioxidant activity of AgNPs. The results revealed that Kf₁-, Kf₂-, and Kf₃-AgNPs exhibit an average diameter of 39.9, 111, and 42 nm, respectively. The calculated ζ-potential of Kf₁-, Kf₂-, and Kf₃-AgNPs were −20.5, −10.6, and −7.9 mV, respectively. The UV-vis analysis of the three samples demonstrated characteristic absorption bands within the range of 350–450 nm, which confirmed the formation of AgNPs. The FTIR analysis of AgNPs exhibited a series of bands from 3500 to 750 cm⁻¹, related to the presence of extracts on their surfaces. SEM observations unveiled that Kf₁- and Kf₂-AgNPs adopted structural arrangements related to nano-popcorns and nanoflowers, whereas Kf₃-AgNPs were spherical in shape. It was determined that treatment with Kf₁-, Kf₂-, and Kf₃-AgNPs was demonstrated to inhibit the growth of E. coli, S. aureus, and P. aeruginosa in a dose-dependent manner (50–300 μg/mL). Within the same range, treatment with Kf₁-, Kf₂-, and Kf₃-AgNPs decreased the generation of DPPH (IC₅₀ 57.02–2.09 μg/mL) and H₂O₂ (IC₅₀ 3.15–3.45 μg/mL) radicals. This study highlights the importance of using inorganic nanomaterials to improve the biological performance of plant extracts as an efficient nanotechnological approach.

In this work, the leaves of K. tomentosa were macerated with hexane, chloroform, and methanol, respectively. The phytochemical profiles of hexane and chloroform extracts were unveiled using GC/MS, whereas the chemical composition of the methanol extract was analyzed using UPLC/MS/MS. The antibacterial activity of extracts was determined against gram-positive and gram-negative strains through the minimal inhibitory concentration assay, and in silico studies were implemented to analyze the interaction of phytoconstituents with bacterial peptides. The antioxidant property of extracts was assessed by evaluating their capacity to scavenge DPPH, ABTS, and H₂O₂ radicals. The toxicity of the extracts was recorded against Artemia salina nauplii and Caenorhabditis elegans nematodes. Results demonstrate that the hexane and chloroform extracts contain phytosterols, triterpenes, and fatty acids, whereas the methanol extract possesses glycosidic derivatives of quercetin and kaempferol together with sesquiterpene lactones. The antibacterial performance of extracts against the cultured strains was appraised as weak due to their MIC₉₀ values (>500 μg/mL). As antioxidants, treatment with extracts executed high and moderate antioxidant activities within the range of 50–300 μg/mL. Extracts did not decrease the viability of A. salina, but they exerted a high toxic effect against C. elegans during exposure to treatment. Through in silico modeling, it was recorded that the flavonoids contained in the methanol extract can hamper the interaction of the NAM/NAG peptide, which is of great interest since it determines the formation of the peptide wall of gram-positive bacteria. This study reports for the first time the biological activities and phytochemical content of extracts from K. tomentosa and proposes a possible antibacterial mechanism of glycosidic derivatives of flavonoids against gram-positive bacteria.

Background: Equisetum hyemale L., commonly known as scouring rush or horsetail, is a perennial plant with significant applications in traditional medicine. Methods: The aerial parts of E. hyemale L. were macerated with hexane, chloroform, and ethyl acetate. The phytochemical profile of the extracts was investigated using chromatography approaches. The biological performance of the extracts was determined using antibacterial, antioxidant, anticancer, and toxicity in vitro and in vivo models. Molecular docking and ADMET analyses were employed to determine interactions with structural components of multidrug resistant bacteria and assess potential toxicological risks. Results: The extracts exert high scavenging activity against ABTS radicals (IC₅₀ 2.57–2.68 μg/mL), but poor antibacterial activity. It was evidenced that treatment with extracts exerts in moderate cytotoxicity on hepatocellular and colorectal cancer cell lines. Toxicity assays unveiled that the extracts decrease the survival rate of C. elegans nematodes after 2 h of exposure to treatment. In silico studies evidenced a high affinity of campesterol and calcitriol towards the DNA gyrase, and the oral bioavailability of farnesol and limonene. Conclusions: Our findings demonstrated the presence of biologically active secondary metabolites in hexane, chloroform, and ethyl acetate extracts from E. hyemale L. This work also demonstrated the biological performance of these extracts in in vitro and in vivo models, and validated the potential pharmacokinetic and pharmacodynamic profile of their phytoconstituents.