Gang Xia

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.

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 5.6-21.2 µg/mL.

Tetracyclic triterpenoids and terpenylated coumarins from the bark of Ailanthus altissima (“Tree of Heaven”)

Tetracyclic triterpenoids (named as altissimanins A-E, 1-5) and a terpenylated coumarin (denominated as altissimacoumarin G, 6), along with fifteen known compounds (7-21) were isolated from the bark of Ailanthus altissima. Structures of compounds 1-6 were established by spectroscopic methods and chemical transformations. Altissimanin A (1) is a tirucallane-type triterpenoid bearing an uncommon oxetane ring in the side-chain, while altissimanins D (4) and E (5) are two unprecedented dimers each consisting of one tirucallane-type and one dammarane-type triterpenoid moiety. All the isolates were evaluated for their cytotoxic effects against a small panel of human cancer cell lines.

Fomentarols A–D, sterols from the polypore macrofungus Fomes fomentarius

Four (1-4) hitherto unknown and seven (5-11) known ergostane-type sterols were isolated from the EtOH extract of the dried fruiting bodies of the polypore macrofungus Fomes fomentarius. On the basis of spectroscopic analysis, the structures of polyhydroxylated sterols 1-4 were elucidated to be (22E,24R)-3β,5α,6β,14α-tetrahydroxyergosta-7,9(11),22-triene (fomentarol A, 1), (22E,24R)-3β,5β,6α,7α-tetrahydroxy-8α,9α-dihydroergosta-14,22-diene (fomentarol B, 2), (22E,24R)-3β,5α-dihydroxy-6β-ethoxyergosta-7,22-diene (fomentarol C, 3), and (22E,24S)-3β,25-dihydroxy-15α-O-β-D-glucopyranosylergosta-7,22-dien-6-one (fomentarol D, 4), respectively. Rings A/B and B/C are in turn cis-fused in compound 2, which is uncommon in natural ergostane-type sterols. The potential biogenetic relationship of 2 and other ergostane-type sterols isolated from F. fomentarius was briefly discussed. Moderate cytotoxic effects of the isolated sterols against a small panel of human cancer cell lines were also established.

Leonurusoleanolides E-J, minor spirocyclic triterpenoids from Leonurus japonicus fruits.

Six new (leonurusoleanolides E-J, 1-6) and five known (7-11) nortriterpenoids were isolated and characterized from the dried fruits of Leonurus japonicus. They all contain a distinctive 19(18→17)-abeo-28-noroleanane-type spirocylclic skeleton with a trans or a cis acyl substituent at C-3 or C-23. Similar to the previously known leonurusoleanolides A/B (7/8) and C/D (9/10), compounds 1/2 and 3/4 were also found to exist as equilibrium mixtures of trans and cis isomers. The isolated pure compounds and mixtures were evaluated for their cytotoxicity against a small panel of human cancer cell lines (BGC-823 and KE-97 gastric carcinoma, Huh-7 hepatocarcinoma, Jurkat T cell lymphoblasts, and MCF-7 breast adenocarcinoma) using the CellTiter-Glo luminescent cell viability assay method. Among them, (2α,3β,17R*,18β)-3-O-(trans-caffeoyl)-19(18→17)-abeo-28-norolean-12-ene-2,18,23-triol (leonurusoleanolide J, 6) showed the most potent cytotoxic activity, with IC50 values less than 10 μM.

Rearranged abietane diterpenoids from the roots of Clerodendrum trichotomum and their cytotoxicities against human tumor cells

The roots of the medicinal ornamental plant Clerodendrum trichotomum yielded a series of rearranged abietane diterpenoids, including three 17(15→16)-abeo-abietane (1-3) and three 17(15→16),18(4→3)-diabeo-abietane (4-6) derivatives. Their structures were elucidated by means of spectroscopic methods. The absolute configuration of (10R,16R)-12,16-epoxy-11,14,17-trihydroxy-6-methoxy-17(15→16)-abieta-5,8,11,13-tetraene-7-one (1) was deduced by a combination of single crystal X-ray diffraction analysis and the observed Cotton effects in its circular dichroism (CD) spectrum. All isolates were tested for their cytotoxicities against five human cancer cell lines (BGC-823, Huh-7, KB, KE-97, and Jurkat). Among them, compounds 4, 6, 9, 10, 12, and 14, each possessing a common 17(15→16),18(4→3)-diabeo-abietane framework, were found to have remarkable cytotoxic effects with IC50 values ranging from 0.83 to 50.99 μM.

Glycosides from the methanol extract of Notopterygium incisum.

Five new (1-5) and twelve known (6-17) different types of glycosides together with a known sesquiterpene triol (18) were isolated from the methanol extract of the rhizomes of Notopterygium incisum. The new structures were elucidated by means of spectroscopic and chemical methods to be pregn-5-en-3 β,20( S)-diol-3- O-bis-β-D-glucopyranosyl-(l → 2,1 → 6)-β-D-glucopyranoside (1), oleuropeic aldehyde 8-O-β-D-glucopyranoside (2), 2( R)-(3,4-dimethoxyphenyl)-propane-1,3-diol-1-O- β-D-glucopyranoside (3), eudesman-3 α,4 α,11-triol-11-O-β-D-glucopyranoside (4), and marmesin-11-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (5). The absolute configuration of the aglycone in compound 3 was assigned by application of Klynes rule.

(24S)-Ergostane-3β,5α,6β-triol from Hedyotis chrysotricha with inhibitory activity on migration of SK-HEP-1 human hepatocarcinoma cells

The methanol extract of the whole plant of Hedyotis chrysotricha demonstrated cytotoxicity against SK-HEP-1 human hepatocarcinoma cells in a primary screening for novel antitumour agents. Bioassay-guided fractionation and purification led to an active principle (24S)-ergostane-3β,5α,6β-triol (1) along with four inactive compounds (2–5). The in vitro transwell migration assay showed that compound 1 remarkably reduced the migration of SK-HEP-1 cells by 78.9% at a dose of 30 µM, without any apoptotic effect on this cell line. Moreover, all the isolated compounds were further evaluated for their cytotoxicities against another four human cancer cell lines (MCF-7, NUGC3, SH-SY5Y and PC-3).

A novel glucagon-like peptide 1 peptide identified from Ophisaurus harti

Glucagon‐like peptide 1 receptor (GLP1R) is a promising target for the treatment of type 2 diabetes. Because of the short half‐life of endogenous GLP1 peptide, other GLP1R agonists are considered to be appealing therapeutic candidates. A high‐throughput assay has been established to screen for GLP1R agonists in a 60 000‐well natural product compound library fractionated from 670 different herbs/materials widely used in traditional Chinese medicines (TCMs). The screening is based on primary screen of GLP1R+ reporter gene assay with the counter screen in GLP1R− cell line. An active fraction, A089‐147, was identified from the screening. Fraction A089‐147 was isolated from dried Ophisaurus harti, and the fact that its GLP1R agonist activity was sensitive to trypsin treatment indicates its peptidic nature. The active ingredient of A089‐147 was later identified as O. harti GLP1 through transcriptome analysis. Chemically synthesized O. harti GLP1 showed GLP1R agonist activity and sensitivity to dipeptidase IV digestion. This study illustrated a comprehensive screening strategy to identify novel GLP1R agonists from TCMs libraries and at the same time underlined the difficulty of identifying a non‐peptidic GLP1R agonist. The novel O. harti GLP1 peptide yielded from this study confirmed broader application of TCMs libraries in active peptide identification. Copyright