Daofeng Chen

Schisanwilsonins A-G and related anti-HBV lignans from the fruits of Schisandra wilsoniana.

Seven new dibenzocyclooctane lignans, schisanwilsonins A-G (1-7), were isolated from the fruits of Schisandra wilsoniana, together with five known lignans (8-12). The structures of these new compounds were elucidated by spectroscopic methods including 2D-NMR techniques. The 12 lignans were tested for anti-hepatitis B virus (HBV) activity in vitro. Schisanwilsonin D (4), schisantherin C (9), deoxyschizandrin (10) and (+)-gomisin K(3) (11) showed anti-HBV activity. 9 exhibited the most potent anti-HBV activity with potency against HBsAg and HBeAg secretion by 59.7% and 34.7%, respectively, at 50 microg/mL.

Schisanwilsonenes A-C, anti-HBV carotane sesquiterpenoids from the fruits of Schisandra wilsoniana.

Three carotane-type sesquiterpenoids, schisanwilsonenes A (1), B (2), and C (3), were isolated from the fruits of Schisandra wilsoniana. Their structures and relative configurations were elucidated on the basis of spectroscopic methods including 2D-NMR techniques, and the structure of 1 was confirmed by a single-crystal X-ray diffraction experiment. Schisanwilsonene A, at 50 microg/mL, exhibited antiviral activity, inhibiting HBsAg and HBeAg secretion by 76.5% and 28.9%.

Neglschisandrins E–F: Two New Lignans and Related Cytotoxic Lignans from Schisandra neglecta

Phytochemical investigation of an ethanolic extract of stems of Schisandra neglecta led to the isolation and identification of two new dibenzocyclooctadiene lignans, designated neglschisandrins E (1) and F (2), and thirteen known lignans. All structures and stereochemistries were determined by spectroscopic methods, including 2D-NMR techniques. The isolates were evaluated for in vitro cytotoxic activity. Among them, compounds 2–6 exhibited moderate to weak cytotoxicity against the human colorectal carcinoma HCT-8 cell line with EC50 values of 7.33~19.8 μg/mL. In addition, compounds 2–4 also exhibited marginal cytotoxicity against the human lung carcinoma A549 cell line with EC50 values of 11.8~15.0 μg/mL.

Four new diterpenoids from the roots of Euphorbia pekinensis.

Three new isopimarane diterpenoids (1 – 3) and one new abietane diterpenoid (4) were isolated and identified from the roots of Euphorbia pekinensis, together with four known diterpenoids. Their structures were elucidated on the basis of extensive spectroscopic methods (IR, MS, NMR, and CD), and their cytotoxicities and anticomplement activities were evaluated.

Anticomplement triterpenoids from the roots of Ilex asprella

Five new (1-5) and twenty-eight known (6-33) triterpenoids were isolated from the roots of Ilex asprella. The structures of the new compounds were elucidated by the detailed spectral analysis. The ursane and oleanane triterpenoids were found to show anticomplement activity with some structure-activity relationships. Several triterpenoids (1-3, 6-7) exhibited potent anticomplement activity with the CH50 and AP50 values of 0.058-0.131mg/mL and 0.080-0.444mg/mL, respectively. It was found that caffeoyl group could enhance activity remarkably, followed by coumaroyl and feruloyl group. The 28-carboxyl group was also important to anticomplement activity for the triterpenoids. However, the triterpenoids with lactone ring (4, 9-14) exhibited weak activity and triterpenoid glycosides (5, 23-33) showed no inhibition. The targets of several bioactive triterpenoids in complement activation cascade were identified as well.

Renchangianins F and G: two new sesquiterpenoids from Kadsura renchangiana

Abstract Phytochemical investigation on the stems of Kadsura renchangiana led to the isolation of two new sesquiterpenoids, renchangianins F and G (1 and 2). Their structures were elucidated by spectroscopic methods, including 2D NMR techniques. The in vitro cytotoxic activities of the isolates were studied against HepG2, A549, and LN229 cancer cell lines.

A novel dimeric flavonol glycoside from Cynanchum acutum subsp. sibiricum

Abstract A novel dimeric flavonol glycoside, Cynanflavoside A (1), together with six analogues, kaempferol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (2), quercetin-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (3), kaempferol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (4), quercetin-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (5), kaempferol-3-O-β-D-glucopyranosyl-7-O-α-L-rhamnopyranoside (6), and quercetin-3-O-galactoside (7) were isolated from the n-butyl alcohol extract of Cynanchum acutum subsp. sibiricum. Their structures were determined spectroscopically and compared with previously reported spectral data. All compounds were evaluated for their anti-complementary activity in vitro, and only compound 5 exhibited anti-complement effects with CH50 value of 0.33 mM.

Oplopane Sesquiterpenes from Ligularia knorringiana and Their Anti-Complementary Activity

Three new oplopane sesquiterpenes, knorringianalarins D – F (1 – 3, respectively), and five known analogues (4 – 8, respectively), were isolated from the roots and rhizomes of Ligularia knorringiana. The structures of three new compounds were identified as 4‐acetoxy‐11α,12‐epoxy‐2β‐hydroxy‐3β‐(2‐methylbutyryloxy)‐9α‐(4‐methylsenecioyloxy)oplop‐10(14)‐ene (1), 3β,4‐diacetoxy‐9α‐(4‐acetoxy‐4‐methylsenecioyloxy)‐11α,12‐epoxy‐8α‐(2‐methylbutyryloxy)oplop‐10(14)‐ene (2), and (1R,5R,6R,7R,9R)‐5,9,11‐trihydroxy‐4,15‐dinoroplop‐10(14)‐en‐3‐one (3) based on spectroscopic methods including 1D‐ and 2D‐NMR, mass spectrometry, and CD spectroscopy techniques. All compounds were evaluated for their anti‐complementary activity on the classical pathway of the complement system in vitro. Among which, three oplopane sesquiterpenes (3, 7, and 8) exhibited better anti‐complementary effects with CH50 values ranging from 0.33 to 0.89 mm, which are plausible candidates for developing potent anti‐complementary agents.

Iridoids from Pedicularis verticillata and Their Anti-Complementary Activity

Three new iridoids named as pediverticilatasin A – C (1 – 3, resp.), together with five known iridoids (4 – 8, resp.) were isolated from the whole plants of Pedicularis verticillata. The structures of three new compounds were identified as (1S,7R)‐1‐ethoxy‐1,5,6,7‐tetrahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4(3H)‐one (1), (1S,4aS,7R,7aS)‐1‐ethoxy‐1,4a,5,6,7,7a‐hexahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4‐carboxylic acid (2), (1S,4aS,7R,7aS)‐1‐ethoxy‐1,4a,5,6,7,7a‐hexahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4‐carbaldehyde (3). Their structures were elucidated on the basis of spectroscopic methods and compared with the NMR spectra data in the literature. All compounds were evaluated for their anti‐complementary activity on the classical pathway of the complement system in vitro. Among which, compounds 1, 3, and 6 exhibited anti‐complementary effects with CH50 values ranging from 0.43 to 1.72 mm, which are plausible candidates for developing potent anti‐complementary agents.

Anticomplement compounds from Polygonum chinense

Five new compounds including two phenyldilactones (1, 2), two coumarins (3, 4) and a dimer of N-E-feruloyl tyramine (5) together with twenty-three known compounds (6-28) were isolated from a medicinal plant Polygonum chinense. The structures of the new compounds were established by detailed spectral analysis. The absolute configurations of 1 and 5 were elucidated by Moshers method, Mo2(OAc)4-induced electronic circular dichroism (ECD) data, and ECD calculation. All the compounds were found to show potent anticomplement activity with CH50 and AP50 values ranging from 0.18 to 1.45 mM, and 0.26 to 2.80 mM, respectively. Phenyldilactones and phenylpropionic tyramines were firstly reported as anticomplement agents. The targets of compounds 1, 3, 5 and 10 in complement activation cascade were identified as well.