1H-NMR-Based Biochemometric Strategy to Identify Transient Receptor Potential Vanilloid 1-Stimulating Compounds from Alpinia officinarum Rhizome.

Abstract

This study established a ¹H-NMR-based biochemometric approach for the isolation of biologically active compounds from complex extracts. In both pharmacognosy and natural product chemistry, reliably isolating bioactive compounds typically necessitates repeating time-consuming and laborious isolation and purification steps, presenting a bottleneck in many studies. We applied biochemometric methods to accurately estimate active compounds, thus minimizing the number of assays and isolation steps. The rhizomes of Alpinia officinarum Hance (Zingiberaceae) have been continuously prescribed in traditional Japanese medicine as stomachics and analgesics, despite a limited understanding of the mechanisms underlying these effects. Additionally, transient receptor potential vanilloid subtype 1 (TRPV1) plays a role in modulating nociception, respiratory defense responses, and gastrointestinal protection. Accordingly, ¹H-NMR-based biochemometry was employed to search for TRPV1-active components in A. officinarum rhizome extracts by combining TRPV1 activity intensity with ¹H-NMR data. However, initially, the active component could not be identified because the principal component analysis loading plot primarily displayed only buckets of primary metabolites. Consequently, we applied orthogonal partial least squares to the ¹H-NMR spectra, which allowed us to identify specific spectral bins at 1.66 ppm (aliphatic) and 7.02, 6.98, 6.82, and 6.74-6.58 ppm (aromatic), correlating with TRPV1-stimulating activity. Based on this prediction, diarylheptanoids were swiftly identified, and their potential to activate TRPV1 was confirmed by administering the identified compounds to TRPV1-expressing cells. These findings highlight the potential of chemometric analysis using ¹H-NMR spectroscopy for identifying the chemical classes responsible for the bioactive properties of complex crude drug extracts.