Green synthesis, in vivo and in vitro pharmacological studies of Tamarindus indica based gold nanoparticles.

The current investigation aims to synthesize gold nanoparticles (AuNPs) from aqueous extract of Tamarindus indica and to evaluate the in vitro anti-bacterial and in vivo sedative and anelgescic activities of crude extract as well as synthesized AuNPs. Several methods have been reported to synthesize AuNPs; however, most of them were not ecofriendly. In the present study, the green synthesis of AuNPs has been carried out. Using the green synthesis method, AuNPs of T. indica were synthesized at room temperature (25 °C) by mixing 5 mL of HAuCl4 (1 mM) with 1 mL of T. indica seed extract solution. This extract solution was prepared by taking 5 gm dry seeds in 100 mL of double deionized water with continuous stirring for up to 24 h at 80 °C. The stability of AuNPs was confirmed with the help of relevant experimental techniques including ultraviolet-visible (UV/Vis) showing maximum absorbance at 535-540 nm, Fourier transform infrared showing a broad signal at 3464 cm-1 which can be attributed to either amide or hydroxyl functionalities and atomic force microscopy analysis showed that the biomaterial surrounding AuNPs was agglomerated which proves the formation of discrete nanostructutres. These AuNPs have been evaluated for their antibacterial potential. The results revealed good antibacterial activity of the samples against. Klebsiella pneumonia, Bacillus subtilis and Staphylococcus epidermidis with 10-12 mm zone of inhibition range. The AuNPs were also found stable at high temperature, over a range of pH and in 1 mM salt solution. Moreover, the crude extract and respective AuNPs also exhibited interesting sedative and analgesic activities. Hence, we focused on phytochemicals-mediated synthesis of AuNPs considered as greatest attention in the treatment of anti-bacterial, analgesic, and sedative.

Green synthesis and biomedicinal applications of silver and gold nanoparticles functionalized with methanolic extract of Mentha longifolia.

This study deals with facile and rapid synthesis of silver nanoparticles (AgNPs) and Gold nanoparticles (AuNPs) using Mentha longifolia leaves extracts (MLE). The synthesized AgNPs and AuNPs were characterized by UV-visible spectroscopy (UV-Vis), Fourier transformed infra-red spectroscopy (FT-IR), atomic force microscopy (AFM) and transmission electron microscopy (TEM) techniques. The phytochemical analysis showed the presence of bioactive secondary metabolites, which are involved in the synthesis of nanoparticles (NPs). The surface plasmon resonance (SPR) observed at 435 and 550 nm, confirmed the green synthesis of AgNPs and AuNPs, respectively. The TEM images showed poly dispersed and round oval shapes of Ag and Au NPs with an average particles size of 10.23 ± 2 nm and 13.45 ± 2 nm, respectively. TEM results are in close agreements with that of AFM analysis. The FT-IR spectroscopy revealed the presence of OH, -NH2 and C = O groups, which involved in the synthesis of NPs. The MLE and their AgNPs and AuNP exhibited good in vitro antibacterial and anti-oxidant activities. Moreover, MLE and NPs also showed in vivo analgesic activities in mice, and excellent sedative properties in open field test paradigm.