An appraisal of cuticular wax of Calotropis procera (Ait.) R. Br.: Extraction, chemical composition, biosafety and application.

Plastic and polythene as hydrophobic materials become a grave concern due to their non-biodegradable nature, cumbersome recycling and waste management. Cuticular wax derived from Calotropis procera is explored as an eco-friendly and safe hydrophobic material. The effects of duration of exposure to solvent, solvent type, size and side of the leaf on cuticular wax yield have been studied. Leaf with the smallest area (10 cm-25 cm) was found to be the most suitable to isolate the wax. GC-MS analysis of the wax revealed that the wax consists of mainly esters, alkane and alkene. Mitochondrial reductase (MTT) and lactate dehydrogenase (LDH) assay have been carried out on M5S cell line at various concentrations and the results indicate that up to 1 μg/ml (acetone as solvent) and 3 μg/ml (chloroform as solvent) use of wax has no toxic effect. To evaluate the hydrophobic potential of the wax in developing hydrophobic paper water regains and contact angle has been measured. The gain in hydrophobicity of the paper is evident from the rise in contact angle (≥90˚) of paper coated with wax. Scanning electron micrograph and FTIR spectra generated physical and chemical evidence of coating of wax on paper.