Abstract
The present study aimed at isolating and elucidating the structure of the main components of Pistacia khinjuk L. and exploring its potential anti-inflammatory effect in different experimental models. The extract was evaluated for anti-inflammatory activity by measuring paw volume in three experimental models. Then, prostaglandin E-2 (PGE(2)) level, ear edema, tissue myeloperoxidase (MPO) activity, histopathology, nitric oxide (NO) level, and tumor necrosis factor-a (TNF-alpha) level were assessed. Seven phenolic compounds, mainly flavonoids and galloylated compounds, were isolated from the aqueous methanol extract: gallic acid (1), methyl gallate (2), quercetin-3-O-beta-d-C-4(1)-galactopyranoside (hyperin) (3), myricetin- 3-O-alpha-L-C-1(4)-rhamnopyranoside (myricitrin) (4), 1,6-digalloyl-beta-d-glucose (5), 1,4-digalloyl-beta-d-glucopyranoside (6), and 2,3-di-O-galloyl-(alpha/beta)-C-4(1)-glucopyranose (nilocitin) (7). The anti-inflammatory activity was evidenced by decreased carrageenan-induced rat paw edema and PGE(2) elevation. In the croton oil-induced ear edema model, MPO activity was significantly inhibited, and inflammatory histopathological changes were ameliorated. In the rat air pouch model, NO generation and TNF-a release were significantly inhibited. The isolation and nuclear magnetic resonance spectral data of compound 6 from the genus Pistacia are revealed for the first time. Also, P. khinjuk L. aqueous methanol extract possesses anti-inflammatory activity in several experimental models.