Antioxidant, anti-alzheimer, anti-diabetic, and anti-inflammatory activities of the endemic halophyte Limonium spathulatum (Desf.) kuntze on LPS-stimulated RAW264 macrophages

The present paper reports on both the quantification of phenolic compounds and the determination of the biological activities of the endemic North African halophyte Limonium spathulatum (Desf.) Kuntze. The extracts were prepared by maceration using three solvents (methanol, methanol: water (5:1), and chloroform). Phenolic compounds were spectrophotometrically quantified with the microplate method, while the bioactivity of the extracts was assessed by determining of antioxidant activity, inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-glucosidase, and nitric oxide (NO) production by murine macrophages (RAW 264). The polar extracts showed high contents of total phenolic and exhibited the highest antioxidant potential. Moreover, methanol: water extract demonstrated the best inhibitory activity against AchE and BchE with IC50values of 3.28±0.16 µg/ml and 26.64±0.96 µg/ml, respectively. Both methanol: water and methanol extracts were found to be more effective in inhibiting α-glucosidase (IC50: 2.83±0.19 and 5.03±0.03 µg/ml, respectively) than the positive control acarbose, which gave a high IC50 value (275.43±1.59 µg/ml). Additionally, the methanol extract displayed the highest anti-inflammatory activity inhibiting the release of NO by 86.21% at 100 μg/ml in LPS-stimulated RAW 264 cells. The findings issued from the present study showed the multiple therapeutic actions of L. spathulatum and can be considered as a potential and valuable source of bioactive compounds.