Jin-Feng Hu

Triterpenoids and steroids from the fruits of Melia toosendan and their cytotoxic effects on two human cancer cell lines.

Ten new triterpenoids, named meliasenins I-R (1-10), one new steroid (11), and 11 related known compounds (12-22) were isolated from fruits of Melia toosendan. The structures of the new compounds were established on the basis of spectroscopic methods, including 2D NMR techniques and mass spectrometry. The relative configuration of 1, (20R*,23E)-25-hydroperoxyeupha-7,23-diene-3β,16β-diol (meliasenin I), was confirmed by single-crystal X-ray diffraction analysis. All isolated triterpenoids (1-10, 12-15) and two steroids (11, 20) were tested for their cytotoxicity against U20S human osteosarcoma and MCF-7 human breast cancer cells using the MTT assay, and some of them were significantly cytotoxic (IC(50) <10 μg/mL). The insecticidal properties of compounds 1-15 and 20 were also briefly evaluated.

Antiproliferative and apoptotic sesquiterpene lactones from Carpesium faberi.

Four new (1-4) and 13 known (5-17) sesquiterpene lactones along with two known diterpenes (18, 19) were isolated from the whole plant of Carpesium faberi. The new structures were elucidated by means of spectroscopic techniques and some chemical transformations to be pseudoguaian-1α(H)-8α,12-olide-4β-O-β-d-glucopyranoside (1), 4β,10α-dihydroxy-5α(H)-1,11(13)-guaidien-8α,12-olide (2), 4β,10β-dihydroxy-5α(H)-1, 11(13)-guaidien-8β,12-olide (3), and (4S)-acetyloxyl-11(13)-carabren-8β,12-olide (4). All isolates were tested against MCF-7 human breast cancer cells using the MTT assay. Among them, the sesquiterpene lactones (except tomentosin 17) possessing an α-methylene-γ-lactone moiety were found to have in vitro antiproliferative activities, with IC(50) values of 3.0-38.8μg/mL. The effects of four selected sesquiterpene lactones (guaianolide 2, carabranolide 4, pseudoguaianolide 9, eudesmanolide 13) on the cell cycle were examined using flow cytometry (FCM).

Antiproliferative and apoptotic activities of linear furocoumarins from Notopterygium incisum on cancer cell lines.

Bioassay-guided fractionation of the antiproliferative chloroform extract of the traditional Chinese medicine Qiang-Huo (Notopterygium incisum) led to the isolation of nine linear furocoumarins (1- 9). All the isolates were tested against two human cancer cell lines (HepG-2 and MCF-7) and a rat cancer cell line (C6) using the MTT assay method. Among them, notopol (1), notopterol (2), 5-[(2 E,5 Z)-7-hydroxy-3,7-dimethyl-2,5-octadienoxy]psoralene (3), and 5-[(2,5)-epoxy-3-hydroxy-3,7-dimethyl-6-octenoxy]psoralene (4) showed significant antiproliferative activity against the HepG-2 and C6 cancer cell lines, with IC(50) values of 7.7-24.8 microg/mL (5-FU: ca. 5 microg/mL). Compounds 1- 3 also showed moderate cytotoxicity against the MCF-7 cancer cell line, with IC(50) values of 39.4-61.3 microg/mL (5-FU: 17.3 microg/mL). The cell cycle-specific inhibition and apoptosis induced by compounds 1 and 2 were determined using flow cytometry. The structure-activity relationship (SAR) is briefly discussed herein. It was found that the presence of a free hydroxy at the lipophilic side chain linked to C-5 of the linear furocoumarins was essential for their in vitro antiproliferative activity.

Casuarinines A–J, Lycodine-Type Alkaloids from Lycopodiastrum casuarinoides

Ten new lycodine-type alkaloids, named casuarinines A-J (1-10), along with eight known analogues (11-18), were isolated from the whole plant of Lycopodiastrum casuarinoides . The new structures were established by spectroscopic methods and chemical transformations. Casuarinines A-D (1-4) and J (10) are common lycodine alkaloids possessing four connected six-membered rings, while tricyclic casuarinines E-H (5-8) are the piperidine ring cleavage products. In particular, casuarinine I (9) has an unprecedented five-membered tetrahydropyrrole ring instead of the piperidine ring. A plausible biosynthetic pathway to 9 is proposed. Among the compounds reported, casuarinine H (8) exhibited significant neuroprotective effect against hydrogen peroxide (H₂O₂)-induced neuronal cell damage in human neuroblastoma SH-SY5Y cells, while casuarinines C (3) and I (9) showed moderate inhibitory activity against acetylcholinesterase (AChE).

Steroids from the leaves of Chinese Melia azedarach and their cytotoxic effects on human cancer cell lines.

Three new (1-3) and several known (4-6) steroids were isolated from the leaves of Chinese Melia azedarach. The structures of the new compounds were elucidated by means of spectroscopic methods including 2D NMR techniques and mass spectrometry to be (20S)-5,24(28)-ergostadiene-3beta,7alpha,16beta,20-tetrol (1), (20S)-5-ergostene-3beta,7alpha,16beta,20-tetrol (2), and 2alpha,3beta-dihydro-5-pregnen-16-one (3). The cytotoxicities of the isolated compounds against three human cancer cell lines (A549, H460, U251) were evaluated; only compounds 1, 2, and (20S)-5-stigmastene-3beta,7alpha,20-triol (4) were found to show significant cyctotoxic effects with IC(50)s from 12.0 to 30.1 microg/mL.

Gynostemosides A–E, megastigmane glycosides from Gynostemma pentaphyllum

Megastigmane glycosides (1-5) together with seven (6-12) related known compounds were isolated from the whole plants of Gynostemma pentaphyllum. The structures were elucidated by means of spectroscopic methods, including 2D NMR, HR-ESIMS, and circular dichroism (CD), as well as chemical transformations to be (3R,4R,5S,6S,7E)-3,4,6-trihydroxymegastigmane-7-en-9-one-3-O-beta-D-glucopyranoside (gynostemoside A, 1), (3S,4S,5R,6R,7E,9R)-3,4,6,9-tetrahydroxymegastigmane-7-en-3-O-beta-D-glucopyranoside (gynostemoside B, 2), (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-9-O-beta-D-glucopyranoside (gynostemoside C, 3), (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-3-O-beta-D-glucopyranoside (gynostemoside D, 4), and (3S,4S,5S,6S,7E,9R)-3,4,9-trihydroxymegastigmane-7-en-4-O-beta-D-glucopyranoside (gynostemoside E, 5), respectively.

Increased oxidative stress and astrogliosis responses in conditional double-knockout mice of Alzheimer-like presenilin-1 and presenilin-2

Conditional presenilin 1 and presenilin 2 double knockout causes memory dysfunction and reproduces neurodegenerative phenotypes of Alzheimer disease (AD) in mice. Oxidative stress has been long implicated predominantly in amyloidosis-mediated AD pathologies; however, its role in response to the loss-of-function pathogenic mechanism of AD remains unclear. In this study, we examined the oxidative stress status in PS1 and PS2 double-knockout (PS cDKO) mice using F(2)-isoprostanes (iPF(2alpha)-III) as the marker of lipid peroxidation. Lipid peroxidation was enhanced in a gender- and age-related manner in the PS cDKO mice independent of brain Abeta deposition. Such oxidative abnormalities predominantly in cerebral cortex at 2-4 months of age preceded the onset of many pronounced AD neuropathologies, suggesting that increased lipid peroxidation is not only an early pathophysiological response to PS inactivation, but also a potential culprit responsible for the AD-like neurodegenerative pathologies in the PS cDKO mice. Western blot analysis of cortical glial fibrillary acidic protein demonstrated an increased astrogliosis response to PS inactivation, in particular in the PS cDKO mice at as young as 2 months of age, suggesting that lipid peroxidation and neuronal injury may be closely associated with the loss-of-function neuropathogenic mechanism of AD.

Cytotoxic Triterpenoids and Steroids from the Bark of Melia azedarach

Two new triterpenoids (1, 2) and two new steroids (3, 4) along with twelve related known compounds (5-16) were isolated from the bark of Melia azedarach. The new structures were elucidated by means of spectroscopic methods and molecular modeling studies and found to be 21,24-cycloeupha-7-ene-3 β,16 β,21 α,25-tetrol (1), 3 β-acetoxy-12 β-hydroxy-eupha-7,24-dien-21,16 β-olide (2), 29-hydroperoxy-stigmasta-7,24(28) E-dien-3 β-ol (3), and 24 ξ-hydroperoxy-24-vinyl-lathosterol (4). All isolated compounds were tested for their cytotoxic activity against three human cancer cell lines (A549, H460, HGC27) using the CellTiter Glo™ luminescent cell viability assay. Among them, compounds 2- 4, 24 ξ-hydroperoxy-24-vinyl-cholesterol (6), kulinone (7), meliastatin 3 ( 8), 3-oxo-olean-12-en-28-oic acid (10), and (22 E,24 S)-5 α,8 α-epidioxy-24-methyl-cholesta-6,22-dien-3 β-ol (12) were found to have cytotoxic effects, with IC₅₀ values of 5.6-21.2u2009µg/mL.

ent-Abietane-Type and Related Seco-/Nor-diterpenoids from the Rare Chloranthaceae Plant Chloranthus sessilifolius and Their Antineuroinflammatory Activities

Fourteen new ent-abietane-type diterpenoids, sessilifols A-N (1-14), and three related new norditerpenoids (15-17) were isolated from Chloranthus sessilifolius. The absolute configurations were determined by single-crystal X-ray diffraction analysis, the modified Moshers method, and/or the observed Cotton effects in their electronic circular dichroism spectra. Sessilifols A (1) and B (2) possess an uncommon five-membered C-ring rearranged by oxidative cleavage of the C-13/C-14 bond in abieta-7,13-diene followed by the formation of a new C-C bond between C-12 and C-14. Sessilifol C (3) is a rare 7,8-seco-9-spiro-fused ent-abietane, whereas sessilifol O (15) represents the first example of a naturally occurring 14-norabietane-type diterpenoid. Compounds 6 and 9 were found to have moderate antineuroinflammatory activities by inhibiting the nitric oxide production in lipopolysaccharide-stimulated murine BV-2 microglial cells, with IC50 values of 8.3 and 7.4 μM, respectively.

Antibacterial clerodane diterpenes from Goldenrod (Solidago virgaurea).

Nine clerodane diterpenes, solidagoic acids C-I (1-7), cleroda-3,13(14)-dien-16,15:18,19-diolide (8) and cleroda-3,13(14)-dien-15,16:18,19-diolide (9) were isolated and characterised from the ethanol-ethyl acetate (1:1) extract of Solidago virgaurea. The structures were determined by NMR spectroscopic analysis. Several displayed moderate antibacterial activity against Staphylococcus aureus.