A New Alkaloid from Ormosia hosiei Hemsl. et Wils

: A new alkaloid, hositisine E ( 1 ) and nine known compounds ( 2 - 10 ) were isolated from the seeds of Ormosia hosiei Hemsl. et Wils. Compound 1 was identified on the basis of a combination of UV, IR, NMR, CD and HRESIMS data. The structures of the known compounds were determined as isoprunetin ( 2 ), biochanin A ( 3 ), ononin ( 4 ), 4',8-dimethoxy-7- O - β - D -glucopyranosylisoflavone ( 5 ), sphaerobioside ( 6 ), ambocin( 7 ), rutin ( 8 ), kaempferol-3-rutinoside ( 9 ) and narcissin ( 10 ). In the anti-inflammatory activity assay, compounds 1 - 3 , 7 displayed inhibitory effects against lipopolysaccharide-induced interleukin-6release in RAW264.7 macrophages, exhibiting IC 50 values of 19.4 – 58.9 μM.


Introduction
The genus Ormosia (Leguminosae) has been used for a long time as traditional Chinese medicines and decorations with important medicinal and commercial value [1]. Ormosiahosiei Hemsl. et Wils, which is mainly distributed in Fujian, Yunnan, and Sichuan Provinces of People's Republic of China (PRC), has been extensively used in folk medicine to treat rheumatic arthralgia, injuries from falls and irregular menstruations [2]. Previous researches on the Ormosiahave led to the isolation of alkaloids [3][4][5],flavonoids [6,7], lignans [8,9], triterpenes [5], and volatile oils [10]. And these constituents have been indicated to have anti-inflammatory, anti-tumor, and antifungal effects. In our previous search, some new cytisine-like alkaloids and their biological activities have been investigated from the Ormosiahosiei [4,11]. In our continuing phytochemical study, a new alkaloid (1) and nine flavonoids (2-10) were isolated (Figure 1) from the seeds of O.hosiei, and their anti-inflammatory activities were evaluated.

Figure 1
The structures of compounds 1-10

Plant Material
The seeds of the plant OrmosiahosieiHemsl. et Wils were collected from Fuzhou of Fujian province, PRC in Apr. 2017. The voucher specimen (access number: 20170416) was identified by Professor Shuangquan Zou of Fujian Agriculture and Forestry University (FAFU), PRC, and has been storedin College of Plant Protection, FAFU.

Extraction and Isolation
The seeds of O. hosiei (2.9 kg) were dried and crushed. The powder of seeds was sequentially extracted with petroleum ether and ethyl acetate at 90 °C for 3 × 2 h. And the extracts were concentrated under reduced pressure to obtain a petroleum ether extract (317.4 g) and an ethyl acetate extract (47.1 g), respectively.The ethyl acetatecrude extract was fractionated by polyamide with EtOH-H2O (0:1 to 95:5, v/v) to give sixparts (Hd1 -Hd6). Hd1 (13.9 g) was subjected to a PRP-512A column using a EtOH-H2O (0:1 to 1:0, v/v) gradient to give eight fractions (Hd1.   Table 1.

Determination of the Production of IL-6
The inhibitory effects on IL-6 of all compounds were evaluated with Lipopolysaccharide (LPS)stimulated RAW 264.7 cells. Cell cytotoxicity was evaluated by MTT (Sigma, USA) assay. RAW264.7 cells (7 × 10 5 cells/well) were cultured for 18 h in 96-well plate with Dulbeccoʼs modified Eagleʼs medium (DMEM) and then the LPS (1 μg/mL) and test materials were added to the cultured cells to stimulate for 24 h. The production of IL-6 was determined by the ELSIA method previously described [12].