Antimicrobial property of polyvinyl alcohol films containing extracts of Lawsonia inermis and Tamarindus indica

We discuss here the preparation, characterization and antimicrobial properties of polyvinyl alcohol (PVA) based polymer films containing medicinally important plant extracts of Lawsonia inermis (henna) and Tamarindus indica (tamarind). The polymer films are prepared using a simple solution casting technique with concomitant heating at 42 °C. The ultraviolet-visible absorption spectrum and Fourier transform infrared spectroscopy (FTIR) of plant extracts confirm the presence of bioactive compounds, such as, 2-hydroxy, 1,4-naphthoquinone (lawsone) in henna extract and tannins, tartaric acid and reducing sugars in tamarind extract, respectively. FTIR analysis of the films confirms the presence of hydrogen bonding between PVA and tamarind phytochemicals in PVA-tamarind films. The surface topography and the average surface roughness analysis using an atomic force microscopy show that tamarind based polymer films have a lower surface roughness, due to a better interaction between PVA and tamarind phytochemicals, than that in henna based polymer films. Phase contrast microscopy images confirm the absence of polymer aggregation or pull-out in PVA-tamarind films, whereas, phase contrast microscopy images confirming the presence of such aggregation in PVA-henna films. Further, the thermal stability of the polymer films containing plant extract is studied in the temperature range of 30-250 °C. The antimicrobial activity of the films was studied using Kirby-Bauer Disc Diffusion method and the polymer films containing tamarind extract are found to exhibit antimicrobial activity against both E. coli and S. aureus . Quantitative analysis of the antimicrobial property of polymer films containing tamarind extract was carried-out using turbidimetry which further corroborates the antimicrobial property of these films. Thus, PVA-tamarind based films are promising candidates for antimicrobial applications, such as, in wound dressing as a ready to use bandage.