Quality Assessment of Clinacanthus nutans Leaf Extracts by GC–MS-based Metabolomics

Clinacanthus nutans is used in tropical Asia and Southeast Asia as a medicinal plant. Traditionally C. nutans had been used to treat diabetes, insect bites, inflammatory diseases, skin problems and cancer. To ensure accurate and consistent preparations of phytomedicines worldwide, quality assurance is crucial. Gas chromatography coupled with mass spectrometry (GC–MS) is a time-saving, specific and reliable technique extensively used for screening, diagnostics and functional genomics. After the extraction and derivatization of C. nutans, a vast number of metabolites from various chemical groups can be characterized in one analytical run. We used the GC–MS-based metabolomics approach to assess the quality of C. nutans leaf extracts from eight dissimilar locations in Malaysia. To differentiate the groups in each sample, four biomarkers were used, namely betulin, lupeol, stigmasterol and squalene. To differentiate and acquire a concise distribution of samples from different locations, multivariate analysis was used, viz. PCA and OPLS-DA. The biplot results suggested that betulin, stigmasterol and squalene were present in samples from Manjung, Alor Setar and Kangar, while lupeol was present in samples from Kepala Batas and Sungai Ara. Besides, squalene was also identified in a sample from the Herbal Garden, AMDI, USM. The proposed markers provide a useful identification tool for the quality assessment of raw materials from C. nutans.