Comparative Antioxidant and Phytochemical Evaluation of Selected Varieties of Colocasia esculenta (L.) Schott Leaves

Sree Kiran, Sree Rashmi, Sree Pallavi, and Muktakeshi are the four commonly cultivated varieties of Colocasia esculenta (L.) Schott. The current study aims to perform phytochemical screening and the antioxidant capacity of the leaf extracts of these varieties. Furthermore, LCMS was used to examine the polyphenolic content of Muktakeshi's ethanolic leaf extract. The phytochemical analysis of the cultivars indicated that all extracts contained beneficial phytocompounds like phenols, terpenoids, flavonoids, alkaloids, saponins, and tannins. The ethanolic leaf extract of Muktakeshi was found to have greater levels of total phenol (39.47±0.47 GAE mg/g) and flavonoid (49.672±0.15 QE mg/g) contents. All the leaf extracts exhibited a moderate antioxidant ability, whereas the ethanolic extract of Muktakeshi exhibited comparatively higher antioxidant potential in both DPPH (88.3±0.58%) and nitric oxide (84.6±0.79%) assays with the least IC50 value. The LCMS studies detected eight polyphenolic compounds like quercetin, kaempferol, gallic acid, caffeic acid, luteolin 7-rutinoside, chlorogenic acid, vitexin, and rutin in the ethanolic leaf extract of Muktakeshi. It is a good source of many potentially effective bioactive compounds and helps to prevent human oxidative stress-associated diseases. The present study found considerable variations in the phenol-flavonoid content and antioxidant properties of the Colocasia varieties studied.

Characterization, Antimicrobial and anticancer activity of biosynthesized silver nanoparticles using Garcinia gummi-gutta (L.) Robs. leaf extracts

Garcinia gummi-gutta is commercially an important plant as its leaves and fruits contain valuable chemical components and are used for various ailments and treatments. Even though, there are minimum reports that have been seen in their exploration of this plant in the field of nanotechnology. So the present study deals with the synthesis of silver nanoparticles from the aqueous and ethanol leaf extracts of G. gummi-gutta and screening its antimicrobial and anticancer properties. Green synthesized silver nanoparticles was characterized by UV-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), fourier transforms infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. In UV-vis spectroscopy, the surface plasmon resonance (SPR) spectrum of silver nanoparticles produced prominent peaks at 365 and 363 nm in aqueous and ethanol leaf extracts of G. gummi-gutta, respectively. Scanning electron microscopy (SEM) and XRD studies showed that the biosynthesized silver nanoparticles from aqueous and ethanol extracts of G. gummi-gutta leaves are spherical and crystalline in nature with an average size of 25 and 23 nm. FTIR spectroscopy reveals that the functional groups are responsible for the synthesis and stabilization of silver nanoparticles. The biosynthesized silver nanoparticles from both plant extracts have remarkable antibacterial and anticancer properties. Through these studies, it was found that silver nanoparticles from the ethanol leaf extract of G. gummi-gutta is more potential than silver nanoparticles from the aqueous leaf extract of G. gummi-gutta. So the present study is a novel attempt to synthesize the silver nanoparticles from this plant and elucidate its antimicrobial and anticancer potential.

Green synthesis of silver nanoparticles from aqueous leaf extract of Medinilla beddomei C B Clarke and its antimicrobial activity

Silver nanoparticles were synthesized from aqueous leaf extract of Medinilla beddomei C B Clarke and evaluated its antimicrobial activity against different bacterial and fungal strains. Here silver nanoparticles were synthesized through green route using leaves of M. beddomei, confirmed by colour change and UV-Visible spectroscopy. The silver nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and X ray diffraction studies. The evaluation of antimicrobial activity of the silver nanoparticles was performed by agar well diffusion method against four bacterial strains and two fungal strains. The formation of silver nanoparticles after treatment was confirmed by the colour change of the aqueous leaf extract into dark brown. TEM and XRD studies revealed that the synthesized silver nanoparticles are almost spherical in shape with an average size of 18.88 nm. The silver nanoparticles synthesized from M. beddomei showed high antimicrobial activity for concentrations of 50µg/ml and 100µg/ml. The highest antimicrobial activity was found against Aspergillus niger. The zone of inhibition of fungal strain shown by A. niger (36.00 ±1.50 mm) at 100µg/ml was higher than that of Ciprofloxacin (28.00±1.57 mm) at 200 mg/ml, the positive control. The silver nanoparticles synthesized from aqueous leaf extract of M. beddomei possess high antimicrobial efficacy against pathogenic bacterial and fungal strains. It can be exploited well in the pharmaceutical industry and for nanomedicine also.