Green Synthesis of Zinc Oxide (ZnO) Nanoparticles Using Aqueous Extract of Shilajit: Their Characterization and Anticancer Activity

UV analysis of aqueous extract of shilajit and zinc oxide nanoparticles (ZnO NPs) of shilajit extract showed the absorbance peaks at 422.40 nm and 357.90 nm. The abosrbance peaks confirms the presence of ZnO NPs in the reaction mixture.

The FTIR spectrum of shilajit extract and ZnO NPs of shilajith extract showed the strong broad absorbance at 3428 cm−1 are due to the stretching vibration of hydroxyl (OH) functional groups. The absorption band at 1633 cm-1 corresponded the stretching vibration of N-H groups. The peak at 1414 cm-1 observed in the spectrum indicate the presence of mono-substituted alkynes. The peak at 1163 cm-1 showed the presence of C-O bonds.

The XRD pattern of ZnO NPs of shilajith extract, characterized by their high intensity, were observed at specific 2θ peak values, namely 31.69°, 34.33°, 36.17°, 47.45°, 56.52°, 62.77°, 67.87° and 68.99°, and can be attributed to the lattice planes (100), (002), (101), (102), (110), (103), (112), and (201), respectively.

The particle size of ZnO NPs of shilajit extract was measured to be 348 nm and the polydispersity index was found to be 0.322.