Multi-Analytical Insight into the Non-Volatile Phytochemical Composition of Coleus aromaticus (Roxb.) Benth

TL;DR

This study explores the non-volatile chemical composition of Coleus aromaticus, revealing new insights into its bioactive compounds.

Contribution

The study provides a detailed characterization of non-volatile metabolites in Coleus aromaticus using multiple analytical methods.

Findings

Chromatographic analyses identified organic acids, polyphenols, and amino acids in Coleus aromaticus.

NMR spectroscopy confirmed diverse polar and non-polar metabolites in the plant.

The study expanded the known phytochemical profile beyond essential oils.

Abstract

Background/Objectives: Coleus aromaticus (Lamiaceae), also known as Cuban oregano or Indian borage, is a semi-succulent perennial species widely used in traditional medicine for its therapeutic and nutritional properties. While its essential oils and aromatic fraction have been extensively investigated, the characterization of its non-volatile metabolites remains limited. The aim of this study was to explore the chemical composition of fresh leaves with a focus on the non-volatile fraction. Methods: Fresh leaves of C. aromaticus were cryogenically treated with liquid nitrogen, ground, and subjected to three different extraction procedures: hydroalcoholic maceration, ethyl acetate maceration, and liquid–liquid partitioning to obtain a dichloromethane organic phase and a hydroalcoholic phase. Extracts and fractions were analyzed by HPTLC and HPLC for metabolic profiling. In addition, the Bligh–Dyer method was applied to separate polar and non-polar metabolites, which were subsequently characterized using NMR spectroscopy. Results: Chromatographic analyses highlighted the occurrence and distribution of organic acids, polyphenols (notably flavonoids), and proteinogenic amino acids. Spectroscopic data confirmed the presence of diverse polar and non-polar metabolites, providing a more detailed chemical fingerprint of C. aromaticus. This integrated approach broadened the phytochemical profile of the species beyond the well-documented essential oils. Conclusions: The results contribute to a better understanding of the non-volatile metabolites of C. aromaticus, offering novel insights into its chemical diversity. These findings highlight the potential of this plant as a valuable source of bioactive compounds, supporting its future application in nutraceutical and pharmaceutical research.

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