To find a potent α-glucosidase inhibitor, 24 tyrosol derivatives with different substituents located at the meta, ortho, or para position of the phenyl group have been synthesised via the Mitsunobu reaction, characterised by ¹H NMR, ¹³C NMR, ESI-MS and IR and evaluated for inhibition. The derivatives possessed varying degrees of in vitro inhibitory activity against α-glucosidase and a relationship between the structure and activity was subsequently established for all compounds. Two of these compounds with substituents at the para position showed significant inhibitory effects surpassing that of the control standard acarbose. Molecular docking studies performed to better understand the binding interactions between the enzyme and the two most active compounds showed substantial binding within the active site of α-glucosidase. Taken together, these results indicate that the position of the substituent plays a crucial role in this inhibition and may facilitate the development of new α-glucosidase inhibitors.

Euphorbia fischeriana has a long-standing history of use in traditional medicine for the treatment of tuberculosis diseases. However, the plant’s therapeutic potential extends beyond this specific ailment. The present study aimed to investigate the antioxidant properties of Euphorbia fischeriana and lay the groundwork for further research on its potential therapeutic applications. Phytochemical tests were performed on the plant, and 11 types of phytochemicals were identified. Ultraviolet–visible spectrophotometry was used to evaluate the active components and antioxidant properties of eight different solvent extracts, ultimately selecting acetone extract for further research. UHPLC-ESI-Q-TOF-MS identified 43 compounds in the acetone extract, and chemical calculations were used to isolate those with high content and antioxidant activity. Three stability experiments confirmed the extract’s stability, while cell viability and oral acute toxicity studies demonstrated its relatively low toxicity. In rats, the acetone extract showed significant protective effects against D-galactosamine-induced liver damage through histopathological examination and biochemical analysis. These results suggest that Euphorbia fischeriana’s acetone extract has potential in treating diseases related to oxidative imbalances. Therefore, this study highlights the plant’s potential therapeutic applications while providing insight into its antioxidant properties.

We investigated the antioxidant activities of different solvent extracts of Angelica amurensis root (AAR). The yield of aqueous extract was the highest. The methanol extract had the highest total phenolic content and total flavonoid content. The aqueous extract showed the highest total carbohydrate content. Methanol and ethanol extracts showed high DPPH and ABTS radical-scavenging abilities, and high antioxidant activities in FRAP and CUPRAC assays. The extract of chloroform and water exhibited high ability to scavenge hydroxyl radicals. All extracts showed high inhibition of β-carotene bleaching, ethyl acetate extract showed the best effect. Ethyl acetate extract exhibited the highest protection against cellular oxidative damage. The best extraction solvent for the active substance in AAR was methanol. AAR may act as a natural antioxidant.

This study investigated the content and biological activity of three solvent extracts of Adonis ramosa Franch (AR), which contains 12 types of phytochemicals. The overall yield and total protein content of the aqueous extract were the highest, and it exhibited the highest hydroxyl and superoxide radical-scavenging abilities, copper chelating abilities, and cupric reducing antioxidant capacity. Ethanol extract had the highest total phenolic, flavonoid, and carbohydrate contents, and it showed the highest iron chelating activity, and HClO- and nitrite-scavenging abilities. Methanol AR extract contained the highest total steroid and tannin contents; it also demonstrated high radical- and reactive oxygen species-scavenging abilities and had the best ferric reducing antioxidant power, which allowed it to effectively prevent β-carotene bleaching. Methanol extract also showed good stability and low toxicity. All tested solvent extracts of AR exhibited weak enzyme-inhibitory activities for four enzymes (α-glucosidase, α-amylase, acetylcholinesterase and butyrylcholinesterase). Overall, AR can serve as a natural antioxidant. Graphical Abstract

Swertia perennis Linnaeus (SP) has been utilised to treat gastritis. We report the qualitative and quantitative phytochemical analysis, antioxidant and enzyme inhibitory activities of SP. The correlation between the biological activities and total bioactive contents of the extracts was also studied via multivariate analysis. Methanol extract contained many active compounds and exhibited good antioxidant activity. Therefore, this was selected for further phytochemical profiling and stability studies. Fourteen compounds were identified by ultra-performance liquid chromatography-electrospray ionisation-orbitrap-mass spectrometry for the first time from this plant. Iridoids, xanthones, and flavonoids were the main components. Methanol extract exhibited good stability and antioxidant capacity in stability studies, with low toxicity, and showed a protective effect on the oxidation of olive and sunflower oils. SP has the potential to be developed and used as an antioxidant, or as urease and XO inhibitors, and its methanol extract could be used as a natural oil stabiliser. Graphical Abstract