A New Triterpenoid Saponin from Camellia oleifera Fruit Hull
- PDF / 168,425 Bytes
- 4 Pages / 594 x 792 pts Page_size
- 82 Downloads / 168 Views
A NEW TRITERPENOID SAPONIN FROM Camellia oleifera FRUIT HULL
Lei Wu,1* Guo-Qun Li,1,2 Zhen Gu,1 Jian-Ping Fu,1 Zi-Jiang Li,3 Jie Zhang,3 Wei Xiong,1* Guang-Qiang Ma,2* and Young-Soo Bae1,4
A new triterpene saponin (1), along with oleanolic acid 3-O-β-D-glucopyranoside (2), were isolated from the fruit shells of Camellia oleifera Abel. The structure of 1 was determined to be 3-O-β-Dglucopyranosyl(1′′→6′)α-L-rhamnosyl 27-hydroxyoleanolic acid-28-O-β-D-glucopyranoside, which was established by analyses of their 1H and 13C NMR spectra with the aid of 2D experiments. Keywords: Camellia oleifera, fruit hull, triterpene saponin, chemical constituents. Camellia oleifera Abel, a green tea plant in the genus Camellia of the Theaceae family, is one of the world′s four woody edible-oil trees and grows only in middle and southern regions of China, such as Hunan, Jiangxi, Fujian, Anhui, and Guangdong Provinces [1]. It has been indicated that C. oleifera Abel. possesses many benefits to health, including antimicrobial, anthelmintic, antidermatophytic, antitussive, antioxidant, and protective effects against many diseases such as cancer, cardiovascular disease, and inflammation [2–7]. The Camellia oleifera fruit shell accounts for more than 60% of the weight of a single C. oleifera fruit and is the byproduct produced by pressing seeds during traditional oil processing. It has not been fully used for a long time and causes much pollution to the environment but contains many active substances including saponins, flavonoids, and polysaccharides [2, 8–12]. In our phytochemical investigation, 10 compounds were isolated from the 95% ethanol extract of fruit shells of C. oleifera Abel [1]. In continuation of our investigation of the plant, we report herein the isolation and characterization of a new 27-hydroxytriterpene saponin, namely 3-O- β -D-glucopyranosyl(1′′→6′) α -L-rhamnosyl 27-hydroxyoleanolic acid-28-O-β-D-glucopyranoside (1), along with one known triterpene saponin oleanolic acid 3-O-β-D-glucopyranoside (2). Compound 1 was isolated as a white amorphous powder, with mp 228–230°C and optical rotation [α]20 D +210° (c 0.2, MeOH). The molecular formula of compound 1 was determined to be C48H78O18 on the basis of EI-MS spectrometric analysis (found [M – H]–, [M]+, and [2M]+ ion peaks are at m/z 941, 942, and 1884, respectively). In the TLC chromogenic reaction, the presence of a purple color when spraying with 10% sulfuric acid–ethanol reagent followed by heating indicated that compound 1 might be a triterpenoid [13, 14]. The IR spectrum of 1 exhibited characteristic absorption bands at 3350, 2969, 1723, 1600, and 1342 cm–1 accounting for hydroxyl, carbonyl, and double bonds [15]. The 1H NMR spectrum and 1H–1H COSY spectra of 1 showed six angular methyl groups as singlets at δ 0.83, 0.85, 0.96, 0.98, 1.08, and 1.27 (each 3H, s), one rhamnose methyl proton signal at δ 1.11, one olefnic proton at δ 5.30 (H-12), one oxygen-bearing methine proton at δ 3.39 (H-3), two signals for oxymethylene group at δ 3.33 and 3.58 (H-27), and sugar
Data Loading...
