Antibacterial, Antifungal, and Antioxidant Activity of Cleome coluteoides: An In Vitro Comparative Study Between Leaves, Stems, and Flowers

Mechanism and Antibacterial Activity of Gold Nanoparticles (AuNPs) Functionalized with Natural Compounds from Plants

Recently, the biosynthesis of gold nanoparticles (AuNPs) has been widely studied and described. In the age of bacterial drug resistance, an intensive search for new agents with antibacterial properties or a new form of antibiotics with effective action is necessary. As a result, the antibacterial activity of AuNPs functionalized with natural compounds is being investigated more frequently. AuNPs biosynthesized with plant extract or functionalized with bioactive compounds isolated from plants could be particularly useful for pharmaceutical applications. The biosynthesized AuNPs are stabilized by an envelope, which may consist of flavonoids, phenolic acids, lipids and proteins as well as carbohydrates and vitamins. The composition of the natural coating affects the size, shape and stability of the AuNPs and is also responsible for interactions with the bacterial cell wall. Recently, several mechanisms of AuNP interactions with bacterial cells have been identified. Nevertheless, they are not yet well understood, due to the large diversity of plants and biosynthesized AuNPs. Understanding the antibacterial mechanisms allows for the creation of pharmaceutical formulations in the most useful form. Utilizing AuNPs functionalized with plant compounds as antibacterial agents is still a new concept. However, the unique physicochemical and biological properties of AuNPs emphasises their potential for a broad range of applications in the future.

Extraction, Isolation and Characterization by HPLC-ESI-MS and Evaluating Chemical Constituents of Hydroalcoholic Extracts of the Invasive Weed Cleome viscosa L

The aim of this study was to extract, identify and isolate the chemical constituents of the root and leaves of Cleome viscosa by liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI-MS). The antioxidant activity and content of associated secondary metabolites in the extracts from different parts of the plant were also measured. The free radical scavenging activity of the methanol extracts of different parts of C viscosa was determined using DPPH assays. A wide range of polar and non- polar compounds were characterized by LC-ESI-MS. Based on the obtained results, 22 and 21 compounds were characterized in the extracts of leaf and root of C viscosa, respectively. Among these compounds, cleomeolide and 57,4′.trihydroxy-6,3.5-trimethoxyflavone, in the leaf extract, and nevirapine and vincetoxicoside A, in the root extract, were considered as main compounds. Phytochemical analysis also showed that the content of bioactive compounds varied remarkably in the extract of different parts of C viscosa. The leaf ethanol extract contained higher amounts of secondary metabolites, namely total phenols and flavonoids. The antioxidant activity of the extracts was also dependent on the plant parts, which was significantly correlated with the content of bioactive compounds studied. A strong free radical scavenging activity was observed for the methanol extract of the leaf (50.3%), followed by the flower (35.2%). In general, this study confirmed a wide range of compounds in different parts of the invasive weed C viscosa, especially in the leaf, with a high free radical scavenging activity.