Shi-Shan Yu

Bioactive triterpenoids from Symplocos chinensis.

A new triterpenoid, 2 g ,3 g ,19 f ,24-tetrahydroxy-23-norurs-12-en-28-oic acid (4), together with three known triterpenoids 3-oxo-19 f ,23,24-trihydroxyurs-12-en-28-oic acid (1), 2 f ,3 g ,19 f ,23-tetrahydroxyurs-12-en-28-oic acid (2), 2 f ,3 f ,19 f ,23-tetrahydroxyurs-12-en-28-oic acid (3), was isolated from the roots of Symplocos chinensis. The new triterpenoid shows significant cytotoxic activity against B16 and BGC-823 cells.

Two New Caffeyol Glycosides from Forsythia suspensa

Two new caffeoyl glycosides of phenethyl alcohol, suspensaside A (1) and suspensaside B (2), were isolated from the fruits of Forsythia suspensa. Also obtained in this investigation were two known compounds forsythiaside (3) and suspensaside (4). The structures of compounds 1 and 2 were established by ID and 2D NMR techniques and chemical methods.

Yuexiandajisu D, a novel 18-nor-rosane-type dimeric diterpenoid from Euphorbia ebracteolata Hayata

Yuexiandajisu D, a novel 18-nor-rosane-type dimeric diterpenoid, was isolated from the roots of Euphorbia ebracteolata Hayata. Its structure was elucidated as 6,3′:7,2′-diepoxy-di-2,3-dihydroxy-18-nor-ros-1(10),2,4,15-tetraene by spectroscopic techniques (HSQC, HMBC, DQF-COSY, TOCSY, NOESY) and chemical methods. Yuexiandajisu D showed moderate cytotoxic activity against cancer cell lines on HCT-8 and Bel-7402, with IC50 values of 2.66 and 3.76 μM, respectively.

Cytotoxic oxygenated triterpenoid saponins from Symplocos chinensis.

A n-butanol-soluble fraction of an ethanolic extract from the roots of Symplocos chinensis showed cytotoxic activity against several cancer cell lines. Bioassay-guided purification led to the isolation and characterization of eight new triterpenoid saponins, symplocososides L-S (1-8). The structures of 1-8 were elucidated as glycosides based on oxygenated aglycons by spectroscopic and chemical methods. These compounds and their hydrolytic products, along with some additional analogues obtained earlier from S. chinensis roots, were evaluated for cytotoxicity in a small cancer cell panel.

Uvamalols D-G: Novel polyoxygenated seco-cyclohexenes from the roots of Uvaria macrophylla

Uvamalols D-F (1 - 4), novel polyoxygenated seco-cyclohexenes, were isolated from the roots of Uvaria macrophylla, and their structures were elucidated by interpretation of spectral data.

Jacaranone analogs from Senecio scandens

Bioassay-guided fractionation of the ethanolic extract of Senecio scandens led to the isolation of four new compounds 4, 5, 7, and 8, along with four known jacaranone analogs (1, 2, 3, 6). Their structures were elucidated on the basis of spectral and chemical evidence. Compound 7 was obtained as a tautomeric mixture of α/β-epimer. The cytotoxic activities of these compounds were evaluated. Among these, compounds 5 and 8 showed potent cytotoxicities. The benzoquinone derivative, jacaranone ethyl ester (1), was the major cytotoxic constituent in this plant with IC50s at a range of 0.5–1.0 μg/ml against various tumor cell lines. The SAR of these jacaranone analogs (1–8), isolated from S. scandens, was also discussed.

BACE1 (Beta‐Secretase) Inhibitory Phenolic Acids and a Novel Sesquiterpenoid from Homalomena occulta

Four phenolic acids, namely 2‐[(Z)‐heptadec‐11‐enyl]‐6‐hydroxybenzoic acid (1), 2‐[(6Z,9Z,12Z)‐heptadeca‐6,9,12‐trienyl]‐6‐hydroxybenzoic acid (2), 2‐[(9Z,12Z)‐heptadeca‐9,12‐dienyl]‐6‐hydroxybenzoic acid (3), and 2‐hydroxy‐6‐(12‐phenyldodecyl)benzoic acid (4), and one sesquiterpene, asperpenoid (5), were isolated from the 95% EtOH extract of the roots of Homalomena occulta, among which 1, 2, and 5 represent new compounds. Further, the phenolic acids 1–4 exhibited BACE1 (β‐secretase) inhibitory activity with IC50 values of 6.23±0.94, 6.28±0.63, 7.93±0.38, and 7.65±0.62 μM, respectively.

Benzophenone C-glucosides from Polygala glomerata Lour

Four new benzophenone C-glucosides, glomeratides A (1), B (2), C (3), and D (4), along with a known compound arrilanin G (5), have been isolated from the whole plant of Polygala glomerata Lour. Their structures were determined by extensive analyses of their spectral data. Compounds 1–5 showed hepatoprotective activities against d-galactosamine-induced toxicity in WB-F344 rat hepatic epithelial stem-like cells.

Four new compounds from the roots of Uvaria macrophylla.

Four new compounds, uvamalols A–C (1–3) and uvarimacrophin A (4), have been isolated from the roots of Uvaria macrophylla. Their structures have been elucidated by spectroscopic methods. The relative configurations of uvamalols A–C have been established by NOE experiments, and the relative stereochemistry of uvarimacrophin A inferred from the diagnostic NMR data by comparison with known model compounds.

Two new triterpenoid saponins from Symplocos Chinensis

Two new triterpenoid saponins, symplocososides X (1) and Y (2) have been isolated from the roots of Symplocos chinensis, and their structures elucidated as 21β-O- cinnamoyl-22α-O-(2-methylbutanoyl)-15α, 16α, 28-trihydroxyolean-12-ene-3β-O-[β-d-glucopyranosyl (1 → 2)]-α-l-arabinofuranosyl (1 → 4)-β-d-glucuronopyranoside (1) and 21β-O-cinnamoyl-22α-O-(2-methylbutanoyl)-15α, 16α, 28-trihydroxyolean-12-ene-3β-O-(3-O-acetyl)-[β-d-glucopyranosyl (1 → 2)]-α-l-arabinofuranosyl (1 → 4)-β-d-glucuronopyranoside (2) by spectral and chemical methods. Their antitumor activities have also been tested.