Cheng-Shan Yuan

Alkaloids from Sophora flavescens Aition

Although the quinolizidine alkaloids and flavonoids, the main active components of the traditional Chinese medicine Sophora flavescens, have been largely investigated, a new matrine alkaloid derivative 9alpha-hydroxy-7,11-dehydromatrine (1) and a rare 1,4-diazaindan-type alkaloid flavascensine (17), together with 15 known alkaloids, were isolated from S. flavescens. The structures were established on the basis of spectroscopic techniques.

Eremophilane-type sesquiterpene lactones from Ligularia hodgsonii Hook

A dimeric eremophilane sesquiterpene lactone with a cyclobutane ring, biliguhodgsonolide (1) and an uncommon seco-sesquiterpene derivative, (4S,5S,6R,10R)-8,9-seco-12-hydroxyeremophil-7(11)-en-14,6;12,8-diolid-9-al (2), were isolated from the roots and rhizomes of Ligularia hodgsonii Hook. Their structures, including the absolute stereochemistry, were elucidated by spectroscopic data and CD analysis. The cyclobutane ring was confirmed by single-crystal X-ray diffraction.

Chemical constituents from the roots of Polygonum bistorta

Investigation of the roots of Polygonum bistorta L. afforded seven compounds including five triterpenoids, a coumarin, and a steroid, the structures of which were identified by EIMS, 1H NMR, 13C NMR, DEPT, and HMBC experiments. All the compounds have been isolated from Polygonum genus for the first time.

Antibacterial constituents from Pedicularis armata

A new neolignan glycoside named armaoside (1), together with six known compounds (2–7), have been isolated from the whole plant of Pedicularis armata Maxim. The structure of 1 was elucidated as erythro-(7S,8R)-1-(4-O-β-d-glucopyranosyl-3-methoxyphenyl)-2-[3,5-dimethoxyl-4-oxo-cinnamic aldehyde]propane-1, 3-diol by spectroscopic and chemical methods. All compounds were assayed against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus.

Chemical constituents of Gentiana macrophylla Pall.

A novel dimeric secoiridoid glucoside, gentimacroside (1), and six known compounds (2–7) were isolated from the roots of Gentiana macrophylla Pall. Their structures were established on the basis of spectroscopic analysis, especially by means of 1D-, 2D-NMR and HRESIMS analyses.

Tirucallane-Type Triterpenoids from Dysoxylum lenticellatum

Ten new tirucallane-type triterpenoids, represented by a rearranged skeleton dysolenticin A (1), dysolenticin B (2), a rare trinortriterpenoid dysolenticin C (3), three tirucallane triterpenoid derivatives with a hemiketal moiety dysolenticins D-F (4-6), dysolenticins G-I (7, 9, 10), and the new alkaloid dysolenticin J (12), together with seven known analogues were isolated from the twigs and leaves of Dysoxylum lenticellatum. Their structures were elucidated by extensive spectroscopic methods, and those of compounds 1, 3, 4, 6, and 10 were confirmed by single-crystal X-ray diffraction experiments. Dysolenticin J (12) showed significant vasodilative effects on intact rat aortic rings with a diastolic degree of 87.4% at 10 μg/mL.

Labdane-type diterpenoids from Croton laevigatus

Sixteen new labdane-type diterpenoids (1–9, 11–17) were isolated from the twigs and leaves of Croton laevigatus, along with 15-hydroxylabda-7,13(E)-diene-17,12-olide (10), which is reported here as a natural product for the first time. Their structures were elucidated on the basis of extensive spectroscopic data interpretation, including UV, IR, NMR, and MS, and comparison with literature data. The structures of compounds 7, 8, 10, 14, 15, 16, and 17 were further confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of 10–17 were determined by the CD exciton chirality method and supported by the single-crystal X-ray diffraction analysis of 10, 14, and 15. Crotonlaevins A (1) and B (2) are the reported first labda-type diterpenoids with a dodecahydronaphtho [1,2-c] furan moiety, and compounds 10–17 are the first reported labda-17,12-olide derivatives isolated from nature.

A novel trinorguaiane-type sesquiterpene from Dictamnus radicis.

A novel trinorguaiane-type sesquiterpene named radicol (1), together with a known sesquiterpene dictamnol (2), was isolated from the petroleum ether–EtOAc–MeOH extracts of the root of Dictamnus radicis Cortex. The structure of 1 was elucidated as 1α,5α-dimethyl-4α,10α-bicyclo[3.5.0]dec-8-en-1β,5β-diol (1) on the basis of IR, HRESIMS, 1H and 13C NMR, DEPT, 1H-1H COSY, HMQC, HMBC and NOESY.

A new benzopyran derivative from Pseuduvaria indochinensis Merr.

From the twigs and leaves of Pseuduvaria indochinensis Merr., a new benzopyran derivative, pseudindochin (1), was isolated together with three known compounds, oligandrol (2), (6E,10E)-isopolycerasoidol (3) and polycerasoidol (4). The structure of compound 1 was elucidated on the basis of extensive spectroscopic data interpretation, including 1D, 2D NMR, HR-ESI-MS, UV and IR. Moreover, compounds 1–4 were evaluated in vitro for their cytotoxic activities against HL-60 and SMMC-7721 cell lines, but these compounds were essentially non-cytotoxic (IC50>30 μg/mL).

Chemical constituents of Aconitum barbatum var. puberulum

Aconitum barbatum var. puberulum is widely used in Chinese folk medicine for the treatment of rheumatosis, rheumatoid arthritis, and some other inflammations [1]. In our phytochemical investigation of traditional Chinese medicines, an aporphine alkaloid corydine (1) [2], a tricarboxylic unsaturated acid, aconitic acid (3) [3], and two diterpenoid alkaloids, tuguaconitine (2) [4] and luciculine (4) [5], were isolated and identified. These compounds were isolated from this plant for the first time. The 13C NMR of compound 1 was reported for the first time, and the 13C NMR of compounds 2 and 4 were reassigned. Plant Material. Aconitum barbatum var. puberulum was collected in Jinzhong Country (Shanxi Province, China) in September 2005 and was identified by Dr. Hu-Yuan Feng (School of Life Science, Lanzhou University). A voucher specimen (No. 20050901AB) is deposited in the Institute of Organic Chemistry, Lanzhou University, China. Extraction and Isolation. The air-dried and powdered herbs (3.9 kg) were percolated with 90% aq. MeOH (7 days × 3) at room temperature. After evaporation of MeOH under reduced pressure, the defatted aqueous extract was then extracted with EtOAc at two pH levels: pH 4–5 and 9–10. The fraction with pH 9–10, 39.0 g, was subjected to column chromatography on silicon gel eluting with CHCl3–CH3OH (99:1–5: 1) to afford 5 fractions (1–5). Fraction 1 (12.5 g) was chromatographed on a silica gel column using petroleum ether–EtOAc (15:1–8:1) gradient to give 1 (40 mg). Fraction 2 (5.2 g) was recrystallized from petroleum ether–Me2CO (4:1) to give 2 (60 mg). Fraction 5 (5.3 g) was further submitted to silica gel CC eluting with petroleum ether–EtOAc–MeOH (4:4:1, 3:3:1, 2:2:1, 1:1:1) to give 4 (23 mg) and 3 (12 mg). Corydine (1): white crystal, mp 147–149°C; EI-MS: m/z 341 [M+]; C20H23NO4; 1H NMR (400 MHz, CDCl3, J/Hz): 6.67 (1H, s, H-3), 2.67 (1H, m, H-4a), 3.18 (1H, m, H-4b), 2.37 (1H, m, H-7a), 3.08 (1H, m, H-7b), 7.05 (1H, d, J = 7.2, H-8), 6.85 (1H, d, J = 7.2, H-9), 3.71 (3H, s, 2-OCH3), 3.87 (3H, s, 10-OCH3), 3.87 (3H, s, 11-OCH3), 8.68 (1H, s, 1-OH); 13C NMR (100 MHz, CDCl3): 142.2 (C-1, s), 149.0 (C-2, s), 111.2 (C-3, d), 123.7 (C-3a, s), 28.8 (C-4, t), 52.6 (C-5, t), 62.6 (C-6a, s), 35.3 (C-7, s), 130.5 (C-7a, s), 124.2 (C-8, d), 110.8 (C-9, d), 151.7 (C-10, s), 143.7 (C-11, s), 126.3 (C-11a, s), 119.1 (C-11b, s), 127.8 (C-11c, s). Tuguaconitine (2): colorless needles, mp 197–199°C; EI-MS (m/z, Irel, %): 437 [M] + (83), 422 (M–CH3) + (100), 406 (M–CH2CH3) + (40); C23H35NO7; 1H NMR (400 MHz, CDCl3): 3.36, 3.41, 3.42 (each 3H, s), 3.21 (1H, d, J = 8.4, H-1), 2.17 (1H, m, H-2a), 1.10 (1H, m, H-2b), 3.06 (2H, m, H-3), 1.35 (1H, s, H-5), 4.34 (1H, s, H-6), 2.84 (1H, dd, J = 8.4, 5.6, H-9), 1.92 (1H, m, H-10), 2.05 (1H, dd, J = 14.0, 7.2, H-12a), 1.54 (1H, dd, J = 14.0, 7.2, H-12b), 2.37 (1H, m, H-13), 3.58 (1H, dd, J = 8.4, 4.0, H-14), 1.72 (1H, t, J = 14.6, 8.2, H-15a), 2.58 (1H, t, J = 7.2, H-15b), 2.85 (1H, s, H-16), 3.89 (1H, s, H-17), 2.55 (1H, d, J = 7.2, H-19a), 3.40 (1H, s, H-19b), 3.00 (2H, m, H-CH2CH3), 1.03 (3H, t, J = 7.2, H-CH2CH3); 13C NMR (100 MHz, CDCl3): 78.9 (C-1, d), 31.8 (C-2, t), 58.8 (C-3, d), 58.7 (C-4, s), 43.2 (C-5, d), 90.6 (C-6, d), 89.6 (C-7, s), 78.7 (C-8, s), 48.7 (C-9, d), 37.9 (C-10, d), 54.1 (C-11, s), 30.9 (C-12, t), 42.6 (C-13, d), 84.5 (C-14, d), 33.6 (C-15, t), 83.1 (C-16, d), 67.3 (C-17, d), 54.6 (C-19, t), 50.2 (C-20, t), 14.1 (C-21, q), 57.9 (6-OCH3, q), 56.5 (14-OCH3, q), 59.0 (16-OCH3, q). Aconitic acid (3): white amorphous powder, C6H6O6; EI-MS m/z: 174.2 [M]+; elemantal analysis: anal. C 41.37%, H 3.42%. Calcd for C6H6O6, C 41.39%, H 3.47%. 1H NMR (400 MHz, CD3COCD3, J/Hz): 6.92 (1H, d, J = 2.5),