Chemical components and bioactivity evaluation of extracts from pear (Pyrus UssuriensisMaxim) fruit

In order to discover the bioactive metabolites of Pyrus ussuriensis Maxim, the systematic chemical and pharmacological investigations were performed. The ethyl acetate extract of the plant displayed activities against ear edema in mice, with an inhibition rate of 17.1%, at a dose of 400mg/kg in vivo. Meanwhile, the ethyl acetate extract showed the best apophlegmatic (inhibition: 49.9%) and antitussive effects (inhibition: 34%) at 800mg/kg in vivo tests, and inhibition of NO production (IC50=0.06 μg/mL). Subsequently, twelve compounds were isolated from the ethyl acetate extract and identified as friedelin (1), daucosterol (2), β-sitosterol (3), betulinic acid (4), oleanolic acid (5), ursolic acid (6), 2-O-buty-1-O’-(2-ethylhexyl) benzene-1,8-dicarboxylate (7), Narcissin (8), 3-hydroxy-3-carboxyl-glutaric acid dimethyl ester (9), 2-hydroxyl -butanediol icacid-4-methyleste (10), myristic acid (11), and (Z)-11-hexadecen-1-ol acetate (12). Among them, compounds 1, 2, 4, 5, 6, and 11 exhibited moderate indirect inhibitory effects on lipopolysaccharide-induced NO and TNF-α production. Practical applications Pyrus ussuriensis Maxim is an edible and medical fruit with many functional properties. Unfortunately, few literatures about bioactive components of this fruit have been investigated. The result indicated that P. ussuriensis have obvious anti-inflammatory, antitussive, and apophlegmatic activities, which were associated with the folk uses of this fruit. Furthermore, this work also suggests a potential use of P. ussuriensis as an important source of natural anti-inflammatory agents and they may also be considered as a functional food.