Effect of flavonoids rich extract of Capparis spinosa on inflammatory involved genes in amyloid-beta peptide injected rat model of Alzheimer's disease.

Objectives: Alzheimer's disease (AD) is one of the most common forms of neurodegenerative diseases. Despite vast ongoing researches focusing on the area, little is known about novel treatments. In this study, we aimed to survey the effects of Capparis spinosa (C. spinosa) extract on amyloid-beta peptide (Aβ)-injected rat.

Methods: For this purpose, hydroalcoholic extracts of caper leaf and fruit were prepared. Total phenolic content, DPPH, and FRAP assay were accomplished to determine antioxidant activity of C. spinosa. HPLC analysis was conducted to measure rutin and quercetin content of selected parts of the plant. Higher levels of flavonoids were observed in leaves of the plant. Twelve male Wistar Aβ-induced rats were randomly divided in four groups of (1) Aβ/DW: Sham-operated group (2) Aβ/DW: Aβ-injected group (3) Aβ/RU: Standard rutin treatment (4) Aβ/CS: C. spinosa extract treatment. After 6 weeks of oral administration, real-time qPCR were conducted to determine APP, BACE-1, PSEN-1, and PSEN-2 genes expression in the hippocampus of rats.

Results: HPLC analysis showed high levels of rutin and quercetin in leaves of Capparis. Rutin was 16939.2 ± 0.01 and quercetin was 908.93 ± 0.01 µg/g fresh weight. In fruit, 1019.52 ± 0.01 rutin and 97.86 ± 0.01 µg/g FW quercetin were measured. Expression of BACE-1, APP, PSEN-1, and PSEN-2 genes in comparison with the control group showed significant down regulation.

Discussion: Results of the study demonstrated that C. spinosa has the potential to down regulate inflammation-involved genes in AD, due to its high levels of flavonoids and could be beneficial as a dietary complement in AD patients.