Graphene Quantum Dots: Green Synthesis, Characterization, and Antioxidant and Antimicrobial Potential.

Antibiotic resistance is becoming more common, emphasising the demand for novel antibacterial treatments. The current investigation describes the green synthesis of graphene quantum dots (GQDs) using M. indica leaves and characterization via Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and ultraviolet-visible (UV-Vis) spectrophotometer. The results showed that GQDs are spherical in shape. In vitro antioxidant and antimicrobial studies indicate that the biological efficacy of synthesized GQDs was higher than the ethanolic leaf extract. GQDs exhibited the highest scavenging efficacy with lowest IC50 (half-maximal inhibitory concentration) value. However, antimicrobial study showed more inhibitory activity of GQDs against all screened microorganisms, i.e., Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa, and fungi, i.e., Aspergillus niger and Aspergillus flavus. Graphene quantum dots facilitate reactive oxygen species (ROS) which ultimately lead to antioxidant and antibacterial activity. This approach would provide an efficient alternate method for tackling microorganisms.

Urease Inhibitory Kinetic Studies of Various Extracts and Pure Compounds from Cinnamomum Genus.

Urease is an enzyme that plays a significant role in the hydrolysis of urea into carbonic acid and ammonia via the carbamic acid formation. The resultant increase in pH leads to the onset of various pathologies such as gastric cancer, urolithiasis, hepatic coma, hepatic encephalopathy, duodenal ulcers and peptic ulcers. Urease inhibitors can reduce the urea hydrolysis rate and development of various diseases. The Cinnamomum genus is used in a large number of traditional medicines. It is well established that stem bark of Cinnamomum cassia exhibits antiulcerogenic potential. The present study evaluated the inhibitory effect of seven extracts of Cinnamomum camphora, Cinnamomum verum and two pure compounds Camphene and Cuminaldehyde on urease enzyme. Kinetic studies of potential inhibitors were carried out. Methanol extract (IC50 980 µg/mL) of C. camphora and a monoterpene Camphene (IC50 0.147 µg/mL) possess significant inhibitory activity. The Lineweaver Burk plot analysis suggested the competitive inhibition by methanol extract, hexane fraction and Camphene. The Gas Chromatography-Mass Spectroscopy (GC-MS) analysis of hexane fraction revealed the contribution of various terpenes. The present study targets terpenes as a new class of inhibitors that have potential therapeutic value for further development as novel drugs.