In the present study, an attempt has been made for the estimation of total phenol and flavonoid content and their radical scavenging properties using Piper betle (L.) leaves. In that, Cultivars i.e., Nov Bangla (NB), Sirugamani-1 (SGM-1) and Halisar Sanchi (HS) were selected for this study. The total phenolic content was ranged from 95.04 to 127.33 mg/100g equivalent to gallic acid and flavonoids were ranged from 51.72 to 61.08 mg/ 100g equivalent to standards of Catechin.  In vitro antioxidant activity was estimated using 1,1-diphenyl-2-picryl hydrazyl (DPPH), free radical scavenging activity, improved ABTS radical cation decolorization assay and ferric reducing antioxidant power (FRAP) assay. Among all the cultivars, The highest Phenol content (93.79%) was observed  for Sirugamani-1 by DPPH method  and highest Phenol content (96.12% & 6791.86 (µg/g) was obtained  for Halisar Sanchi by ABTS assay and FRAP activity  respectively. The study revealed that the leaves of Piper betle (L.) has higher amount of antioxidant activity and it could be used for any novel drug preparation.

In this study, rapid, simple approach was applied for synthesis of silver nanoparticles by using Psidium guajava aqueous leaf extract. The plant extract acts as both reducing agent and capping agent. The green synthesized silver nanoparticles were characterized by using physic-chemical techniques viz, UV-Visible spectroscopy, Fourier Transform Infrared Spectrophotometer [FTIR], Particle size analyser and Scanning electron microscopy. UV-Visible spectrophotometer showed absorbance peak in the range of 419nm.The compounds responsible for silver ions and the functional groups present in plant extract were identified and investigated by FTIR technique. The characterization data reveals that the particles were in crystalline in nature with an average size of 62nm. The silver nanoparticles (Ag NPs) were rapidly synthesized using aqueous extract of guava leaf with AgNO3 solution within 15min at room temperature, without the involvement of any hazardous chemicals. Keywords: Nano particles, green synthesis, Silver,  Psidium guajava and reducing agents.

Plant mediated green synthesis of silver nanoparticles (AgNPs) was carried out with the plant extract of Vitex negundo Linn., a simple method without using harmful chemicals. Herein, a root bark extract is used as reducing and capping agent for synthesizing AgNPs from silver nitrate solution. The characterization of AgNPs were obtained by UV-visible spectrophotometer, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The results were confirmed the presence of silver nanoparticles with UV-visible absorption peak at around 433-443 nm and its crystalline nature by XRD analysis. The FTIR spectrum confirmed that the synthesized AgNPs are stabilized and protected by various functional groups of biomolecules in extract. The SEM morphology showed the triangular or spherical shape of AgNPs with the size in the range of 80-100 nm and EDS confirmed the presence of elemental silver in the sample. The catalytic activity of AgNPs was investigated in the synthesis of 5-substituted 1H-tetrazole. Furthermore, antibacterial profile showed that biopotent AgNPs exhibited moderate to good antibacterial activity.

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