Characterization of Indian pine Oleoresin and Evidence for the existence of Silicon compounds

Abstract

Herein we report the thermal behavior of the Indian pine oleoresin by thermogravimetric, differential thermal analysis (TG-DTA) and powder XRD studies. The natural oleoresin is amorphous as seen from powder XRD studies. However, when heated to a high temperature, it forms crystalline SiO₂ with characteristic reflections of alpha-quartz (SiO₂) as seen in powder XRD patterns. TG-DTA analysis shows that the amount of SiO₂ obtained upon heating is about 75% of the initial resin mass, a huge proportion compared to a maximum of 20% reported in the literature from other plant sources. The FTIR spectra of the oleoresin and its organic extract show a band around 1013-1081 cm^-1, indicating the presence of compounds containing Si-O or Si-O-R groups in oleoresin. Our results suggest that the oleoresin contains a substantial amount of dispersed biosilica and/or several organosilicon compounds, not reported till date.