Comprehensive Investigation of Phytochemical Constituents and Biological Activities of Scabiosa pseudograminifolia Hub.-Mor.

Abstract

Objectives: The aim of this study was to comprehensively investigate the phytochemical composition, including essential oils, fatty acids, and phenolic constituents, and to evaluate the antioxidant and α-amylase inhibitory activities of Scabiosa pseudograminifolia Hub.-Mor. (Caprifoliaceae), an endemic species growing in Sivas province of Türkiye. The plant materials were processed to obtain essential oils, and n-hexane, methanol, and aqueous extracts for chemical and biological evaluations.

Materials and methods: Essential oils were obtained by hydrodistillation. Extracts were prepared using n-hexane, methanol, and water through maceration. The chemical compositions of the essential oil and fatty acids were analyzed using gas chromatography (GC)-mass spectrometry and GC-flame ionization detector (FID). Phenolic compounds were identified by reverse phase high performance liquid chromatography. Total phenolic and flavonoid contents, antioxidant activity [DPPH, Trolox Equivalent Antioxidant Capacity (TEAC), β-carotene bleaching, and Oxygen Radical Absorbance Capacity assays], and α-amylase inhibitory activity were all evaluated using spectrophotometric methods.

Results: Hexadecanoic acid (30.2%) and linalool (15.6%) were the main volatile compounds in the essential oil of S. pseudograminifolia. (Z)-3-Hexenal was the dominant leaf and flower volatile. The primary fatty acids were nonadecanoic and hexadecanoic acids. The aqueous extract exhibited the highest total phenolic (0.52±0.01 mg gallic acid equivalent/_gextract) and flavonoid (0.081±0.002 mg quercetin equivalent/_gextract) contents. Among the tested samples, the essential oil showed the strongest TEAC value (2.39±0.15 mM), while the aqueous extract demonstrated potent antioxidant activity in DPPH (IC₅₅: 0.16±0.04 mg/mL) and β-carotene bleaching assays (inhibitory concentration₅₅: 0.730±0.001 mg/mL). The α-amylase inhibition levels of the extracts were found to be relatively low. Chlorogenic acid was the predominant phenolic compound.

Conclusion: This study presents the first phytochemical and biological investigation of S. pseudograminifolia Hub.-Mor., an endemic species from Türkiye. Essential oil analysis revealed hexadecanoic acid and linalool as major constituents, while nonadecanoic and hexadecanoic acids were predominant among the fatty acids. The methanol extract showed strong antioxidant activity, and chlorogenic acid was identified as a key phenolic compound. These findings support the potential of this species as a valuable source of natural antioxidants.