Quantitative analysis of α-mangostin in hydrophilic ointment using near-infrared spectroscopy

Abstract

The objective of this research was to quantify the α-mangostin content in mangosteen pericarp (MP) ointment as a colloidal dispersion using near-infrared (NIR) spectroscopy. Various concentrations of MP (IP and EP) ointments containing both internal and external pericarps were prepared and the NIR spectra of these ointments were measured. The NIR spectrum of each ointment was correlated with α-mangostin concentration by partial least square (PLS) regression. Validation of the models was performed and their predictive ability was also investigated. The equation and R² value for the prediction of α-mangostin concentration in IP ointment were y = 0.9843x + 0.4441 and 0.9730 and those in EP ointment were y = 0.9569x + 0.1142 and 0.9136, respectively. The biases of the IP and EP ointment models were 0.23 and 0.00, respectively. The results showed that NIR could be a useful tool for the quality control of herbal medicine in hydrophilic ointment without any sample preparation. It could predict α-mangostin content in hydrophilic ointment at very low concentration with sufficient accuracy.

• Garcinia mangostana L.
• herbal product
• non-destructive analysis
• ointments
• partial least square regression

Acknowledgements

We also thank Musashino University and Khon Kaen University for providing us with the chemicals and the apparatus used in this study and Ms. Pensiri Sirikumgorn for MP powder preparation.

Declaration of interest

This work was supported by a grant from the Hitachi Scholarship Foundation.