Bin Guan

2,3-Seco- and 3,4-seco-tirucallane triterpenoid derivatives from the stems of Aphanamixis grandifolia Blume

Six 2,3-seco-tirucallane triterpenoid derivatives (aphanamgrandins A-F), three 3,4-seco-29-nor-tirucallane triterpenoid derivatives (aphanamgrandins G-I), one 3,4-seco-tirucallane triterpenoid (aphanamgrandin J), two tirucallane triterpenoids [aphanamgrandin K and (23Z)-25-hydroxy-tirucalla-7,23-diene-3-one], and three known triterpenoids were isolated from stems of Aphanamixis grandifolia Blume, and their structures were established by extensive spectroscopic and X-ray crystal diffraction studies.

Chemical constituents of the stems of Celastrus rugosus

Two new sesquiterpene pyridine alkaloids rugosusines A and B (1 and 2), and thirty-one known compounds were isolated from the stems of Celastrus rugosus. The structures of new compounds were elucidated by detailed spectroscopic analysis, including HR-ESI–MS and 2D NMR spectroscopic data. All the compounds were isolated from this plant for the first time. The cytotoxicities of these compounds were tested against SKOV3 and MGC-803 cell lines by CCK-8 method.

Aphanamgrandiol A, a new triterpenoid with a unique carbon skeleton from Aphanamixis grandifolia.

Aphanamgrandiol A (1), a novel triterpenoid with a bicyclo[3,2,1]octane ring skeleton produced by 2,3-ring opening and 2,6-ring closure, was isolated from the stems of Aphanamixis grandifolia. The structures were established on the basis of extensive spectroscopic methods, including 1D and 2D NMR techniques, and determined unambiguously by X-ray crystal diffraction. Aphanamgrandiol A showed moderate cytotoxicities against MCG-803, SKOV-3, HCT116 and HepG2 cell lines.

Cytotoxic Pentacyclic Triterpenoids from Prinsepia utilis

Phytochemical investigation of the aerial parts of Prinsepia utilis Royle resulted in the isolation and identification of ten pentacyclic triterpenoids, including two new triterpenoids, 2α-O-trans-p-coumaroyl-3β,19α-dihydroxy-urs-12-en-28-oic acid (1) and 2α-O-cis-p-coumaroyl-3β,19α-dihydroxy-urs-12-en-28-oic acid (2), along with eight known pentacyclic triterpenoids (3-10). The structures were elucidated by extensive spectroscopic methods and by comparison to previously reported spectroscopic data. Most of these compounds showed significant cytotoxic activities against four human cancer cell lines (A549, HCT116, MDA-MB-231, and CCRF-CEM), and the structure-activity relationships are also discussed.

γ-Hydroxynitrile glucosides from the seeds of Prinsepia utilis.

γ-Hydroxynitrile glucosides (prinsepicyanosides A-E) were isolated alongside 11 known compounds from seeds of Prinsepia utilis Royle. Their structures were determined by detailed analysis of NMR and MS spectroscopic data. The relative configuration of prinsepicyanoside C was established by Cu-Kα X-ray crystallography. Prinsepicyanoside A, osmaronin, and 4-(hydroxylmethyl)-5H-furan-2-one exhibited borderline antibacterial activity against Salmonella gallinarum, Vibrio parahaemolyticus, and Vibrio cholera with MIC values of 30.1, 20.7, and 22.8μg/mL, respectively.

Chemical Constituents from Celastrus monospermus

The genus Celastrus belongs to the family Celastraceae, comprising 50 species, of which 30 species are distributed in China [1]. Celastrus monospermus Roxb is a liana plant belonging to the Celastraceae family and is widely distributed in Guizhou, Guangdong, Hainan, Guangxi, and Yunnan Provinces of China. It grows at 300–1500 m above sea level [2]. Previous chemical studies led to the isolation of triterpenens with the friedelane skeleton, which exhibited diverse activities in rheumatism, leukemia, and skin diseases [3–5]. In the course of our research on the chemical constituents of C. monospermus Roxb., 14 compounds were isolated and identified by comparison of their ESI-MS and NMR spectroscopic data with those reported in the literature. Among them, compounds 2–12 were isolated from this plant for the first time. The stems of C. monospermus Roxb were collected from Xishuangbanna, Yunnan Province of China in July 2010 and identified by Prof. Zhang Hangmin (Second Military Medical University). A voucher specimen (No. 201007DZT) has been deposited at the School of Pharmacy, Shanghai Jiao Tong University. The air-dried and powdered plant material (5.0 kg) was extracted three times with 95% EtOH at room temperature. After evaporation of the EtOH under reduced pressure, the viscous residue (296 g) was suspended in H2O and then partitioned successively with petroleum ether and EtOAc, yielding 32.0 g and 78.1 g, respectively. The petroleum ether extract was applied to a silica gel column eluting with petroleum ether–EtOAc gradient (100:1 to 0:100) to obtain five fractions (Fr. 1–Fr. 5). Fraction 2 (2.1 g) was subjected to repeated column chromatography over silica gel eluted with petroleum ether–EtOAc (80:20) to provide compounds 1 (1.2 g) and 9 (10.3 mg). Fraction 3 (2.4 g) was isolated on Sephadex LH-20 (CH2Cl2–MeOH 1:1) to afford compounds 2 (14.0 mg) and 13 (85.9 mg). Compounds 3 (4.4 mg) and 4 (10.0 mg) were purified by crystallization in acetone from Fr. 4 (3.1 g). Fraction 5 (2.1 g) was rechromatographed on silica gel eluted with petroleum ether–EtOAc gradient (10:1 to 0:1) to obtain fractions A–D; Fr. C (0.7 g) was submitted to preparative HPLC [eluted by MeOH–H2O (70:30)] to obtain compounds 10 (13.0 mg) and 11 (7.7 mg). The EtOAc extract was chromatographed on a silica gel column eluting with CH2Cl2–MeOH (50:1 to 5:1) to obtain five fractions (A1–A5). Compounds 8 (33.4 mg) and 14 (57.4 mg) were crystalized from A2 (6.2 g) in acetone. Fraction A3 (5.1 g) was separated by silica gel column again, and the third sub-fraction was subjected to preparative HPLC [eluted by MeOH–H2O (70:30)] to give compounds 7 (5.8 mg) and 12 (5.8 mg). Compounds 5 (14.5 mg) and 6 (4.0 mg) were obtained after purification of A5 (1.3 g) by Sephadex LH-20 (MeOH) and preparative HPLC [eluted by MeOH–H2O (40:60)]. Friedelan-3-one (1). C30H50O. Colorless crystals, mp 229–321 C. ESI-MS (positive) m/z 449 [M + Na] +. Compound 1 was characterized as friedelan-3-one by comparison of the physical and spectral data with the literature [6]. Woodwardic Acid (2). C30H43O3. Colorless crystals, mp 264–265 C. ESI-MS (negative) m/z 455 [M – H]–. Compound 2 was characterized as woodwardic acid by comparison of the physical and spectral data with the literature [7]. Stigmastane-3,6-dione (3). C29H48O2. Colorless crystals, mp 178–180 C. ESI-MS (negative) m/z 427 [M – H] –. Compound 3 was characterized as stigmastane-3,6-dione by comparison of the physical and spectral data with the literature [8]. Stigmast-4-en-6 -ol-3-one (4). C29H48O2. Colorless crystals, mp 189–191 C. ESI-MS (negative) m/z 427 [M – H]–. Compound 4 was characterized as stigmast-4-en-6 -ol-3-one by comparison of the MS and NMR spectral data with the literature [9]. ( )-Catechin (5). C15H14O6. Orange powder, mp 214–216 C. ESI-MS (positive) m/z 313 [M + Na] Compound 5 was characterized as (+)-catechin by comparison of the MS and NMR spectral data with the literature [10].

Chemical Constituents from the Aerial Parts of Prinsepia utilis

Prinsepia species, belonging to the Rosaceae family, includes five species in the world. Prinsepia utilis Royle, one species of Prinsepia genus, is a deciduous shrub growing in uncultivated land found beside brooks and in bushes up to 1000–3000 m above sea level, mainly in Yunnan, Sichuan, Tibet, and other provinces of China [1]. P. utilis has been used in Chinese and Indian folk medicine to treat skin diseases, rheumatism [2], inflammation, and leprosy. Previously, hydrocyanic acids [3 4], fatty oils [5], prinsepiol [6], and triterpenoids [7] have been isolated from this plant. In the course of research on the chemical constituents of the aerial parts of P. utilis, 21 compounds were isolated and identified by physicochemical properties and spectroscopic analysis as dihydroactinidiolide (1) [8], loliolide (2) [9], 3 -hydroxy-5 ,6 -epoxy-7-megastigmen-9-one (3) [10], 9-hydroxy-4,7-megastigmadien-3-one (4) [11], stigmast-5-ene-3 ,7 -diol (5) [12], blumenol (6) [13], (E)-p-coumaric acid (7) [14], ferulic acid (8) [15], (Z)-p-coumaric acid (9) [16], 8 -hydroxyprinsepiol (10) [17], syringaresinol (11) [18], broussonin F (12) [19], quercetin 3-O-D-rutinoside (13) [20], isorhamnetin 3-O-D-rutinoside (14) [21], kaempferol 3-Orutinoside (15) [22], ethyl 4-hydroxybenzoate (16) [23], 4-hydroxybenzaldehyde (17) [24], 4-hydroxy-3,5dimethoxybenzaldehyde (18) [25], 4-methoxyphenol (19) [26], p-hydroxybenzoic acid (20) [15], and 3-hydroxybenzoic acid (21) [27]. All of them were isolated from Prinsepia genus for the first time. The aerial parts of P. utilis were collected from the Weixi Autonomous County of Yunnan Province, P. R. China in August 2010, and authenticated by Prof. Zhang Han-ming, Department of Pharmacognosy, School of Pharmacy, Second Military Medical University. A voucher specimen (No. 201008QCJ) was deposited at the School of Pharmacy, Shanghai Jiao Tong University. The air-dried and powdered aerial parts of P. utilis Royle (4.5 kg) were extracted with 95% EtOH (3 8 L; 48 h, 24 h, and 24 h) at room temperature. The combined extracts were concentrated and successively partitioned with petroleum ether (9 L), EtOAc (9 L), and n-BuOH (9 L). The petroleum ether extract (36.3 g) was chromatographed over a silica gel column with a gradient of petroleum ether–EtOAc (100:1 to 0:100) to give 15 fractions (Fr.1–Fr.15). Fraction 8 (1.3 g) was subjected to column chromatography over silica gel eluted with petroleum ether–EtOAc (20:1) and further purified on preparative HPLC (MeOH–H2O) to yield 1 (3.0 mg). Fraction 15 (1.5 g) was subjected to column chromatography over silica gel eluted with petroleum ether–EtOAc (15:1) and further purified on preparative HPLC (MeOH–H2O) to yield 2 (3.5 mg), 3 (4.0 mg), 4 (5.6 mg), and 5 (10.0 mg). The EtOAc extract (100.3 g) was chromatographed on a series of chromatographs, such as silica gel column, Sephadex LH-20, and prep. HPLC to afford 6 (3.2 mg), 7 (45.8 mg), 8 (14.5 mg), 9 (7.3 mg), 10 (5.8 mg), 11 (7.7 mg), 12 (2.1 mg), 13 (8.0 mg), 14 (23.1 mg), 15 (8.3 mg), 16 (2.0 mg), 17 (6.2 mg), 18 (5.0 mg), 19 (2.2 mg), and 20 (40.0 mg), 21 (4.6 mg).

Chemical Constituents from Inula wissmanniana

One new compound, 4-(3-hydroxybutyl)-3-methylenetetrahydro-2H-pyran-2-one (1), was reported, along with 22 known compounds (2–23), from the whole plant of Inula wissmanniana. The biosynthetic pathway of compound 1 was also hypothesized.