A Comparative Study on UHPLC-HRMS Profiles and Biological Activities of Inula sarana Different Extracts and Its Beta-Cyclodextrin Complex: Effective Insights for Novel Applications

Abstract

Within this particular framework, the extracts obtained from Inula sarana using a variety of solvents, included n-hexane, ethyl acetate, dichloromethane (DCM), 70% ethanol, ethanol, and water. The extracts obtained from n-hexane, ethyl acetate, and DCM were then subjected to a specific method for their incorporation into β-cyclodextrin (β-CD). The establishment of complex formation was validated through the utilization of scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The identification of phytochemical components was executed using UHPLC-HRMS. Furthermore, the total phenolic and flavonoid content was evaluated using the Folin-Ciocalteu assay and the AlCl₃ method. Subsequently, the determination of antioxidant capacity was conducted utilizing DPPH, ABTS, CUPRAC, Frap, PBD, and MCA assays. The enzyme inhibitory activities of the samples (extracts and β-CD complexes) were also examined by AChE, BChE, tyrosinase, α-glucosidase, and α-amylase. The findings indicated that water and 70% ethanol extracts contained the highest phenolic content. One hundred and fourteen bioactive compounds were identified by UHPLC-HRMS analysis. This study unveiled a substantial array of flavonoids, phenolic acid-hexosides and caffeoylhexaric acids within I. sarana, marking their initial identification in this context. Among the various extracts tested, the 70% ethanol extract stood out due to its high flavonoid content (jaceosidin, cirsiliol, and eupatilin) and hydroxybenzoic and hydroxycinnamic acid hexosides. This extract also displayed notably enhanced antioxidant activity, with ABTS, CUPRAC, and FRAP test values of 106.50 mg TE/g dry extract, 224.31 mg TE/g dry extract, and 110.40 mg TE/g, respectively. However, the antioxidant values of the complex extracts with β-CD were generally lower than those of the pure extracts, an observation warranting significant consideration. In terms of enzyme inhibition activity, the ethanol and 70% ethanol extracts exhibited higher inhibitory effects on AChE, tyrosinase, and α-glucosidase. Conversely, n-hexane displayed stronger inhibitory activity against BChE. The ethyl acetate extract demonstrated elevated amylase inhibitory activity. However, the antioxidant values of the complex extracts with β-CD were generally lower than those of the pure extracts, a noteworthy observation, while water and extracts from the I. sarana complex with β-CD exhibited minimal or negatable inhibitory activity against specific enzymes.

Keywords: Inula sarana; SEM; chemical characterization; enzyme inhibitory; β-cyclodextrin.

Figure 1

SEM images of pure β-cyclodextrin (A); Ethyl acetate/β-cyclodextrin (B); Hexane/β-cyclodextrin (C); DCM/β-cyclodextrin (D) inclusion complex.

Figure 2

FT–IR spectra of Ethyl acetate/β–cyclodextrin, Hexane/β–cyclodextrin, DCM/β–cyclodextrin inclusion complex (A), FT–IR spectra of pure β–cyclodextrin and each extract without the presence of β–cyclodextrin (B), with enlarged form between 1550 cm⁻¹ and 400 cm⁻¹ (C).

Figure 3

TIC of studied Inula sarana extracts in negative ion mode; (A) n-hexane extract; (B) ethyl acetate extract; (C) DCM extract; (D) ethanol extract; (E) 70% ethanol extract; (F) water extract; (G) n-hexane/β-CD; (H) ethyl acetate/β-CD; (I) DCM/β-CD.

Figure 4

Venn diagrams showing number of compounds identified from the tested extracts (A). Comparison the identified compounds in the extracts and theirs complexes (B). EA: Ethyl acetate; DCM: Dichloromethane; EtOh: Ethanol; EtOh/Water: 70% Ethanol; BCD: β-cyclodextrin.

Figure 5

Circle heat maps for the results from antioxidant (A) and enzyme inhibitory assays (B) and Pearson correlation values between total bioactive compounds and biological activities (C) (TPC: Total phenolic content; TFC: Total flavonoid content; ABTS: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid; DPPH: 1,1-diphenyl-2-picrylhydrazyl; CUPRAC: Cupric reducing antioxidant capacity; FRAP: Ferric reducing antioxidant power; AChE: acetylcholinesterase; BChE: butyrylcholinesterase; MCA: Metal chelating assay; PBD: Phosphomolybdenum).