Hai-Zhou Li

Lyonin A, a New 9,10‐Secograyanotoxin from Lyonia ovalifolia

Phytochemical studies on the branches and leaves of Lyonia ovalifolia yielded a new grayanane diterpenoid, lyonin A (1), together with two known compounds, secorhodomollolides A and D (2 and 3, resp.). The structure of 1 was elucidated by combination of 1D‐ and 2D‐NMR, and MS analyses. Compound 1 turned out to be a new, highly O‐acylated grayanane diterpenoid, of which ring B has undergone an oxidative cleavage between C(9) and C(10), yielding a system differing from the previously reported grayanane type with a 5/7/6/5 ring system. Results of the cAMP regulation activity assay showed that compounds 2 and 3 at 50 μM induced a significantly decreased cAMP level in N1E‐115 neuroblastoma cells (p<0.001), indicating neuropharmacological potential.

New grayanol diterpenoid and new phenolic glucoside from the flowers of Pieris formosa

A new grayanol diterpenoid, grayanotoxin XXII (1), and a new phenolic glucoside, benzyl 2-hydroxy-4-O-[β-xylopyranosyl(1″ → 6′)-β-glucopyranosyl]-benzoate (2), were isolated from the flowers of Pieris formosa. Their structures were determined on the basis of spectroscopic analysis and chemical methods.

Pierisformotoxins A-D, Polyesterified Grayanane Diterpenoids from Pieris formosa and Their cAMP-Decreasing Activities

Four highly acylated diterpenoids, designated as pierisformotoxins A–D (1–4, resp.), along with 26 known compounds, were isolated from the flowers of Pieris formosa. Among them, pierisformotoxins A and B (1 and 2, resp.) were new highly acylated grayanane diterpenoids, of which the five‐membered ring A has undergone an oxidative cleavage between C(3) and C(4), followed by lactonization, to give rise to a five‐membered lactone ring between C(3) and C(5), differing from the previously reported grayanane diterpenoids with a 5/7/6/5 ring system. Results of the cAMP‐regulation‐activity assay showed that pierisformotoxin C (3) at 10 μM (inhibitory ratio (IR): 10.1%) or 2 μM (9.8%), and pierisformotoxin B (2) at 50 μM (13.9%) significantly decreased the cAMP level in N1E‐115 neuroblastoma cells (p<0.05).

Schisanlactone H and sphenanthin A, new metabolites from Schisandra sphenanthera

From the fruits of Schisandra sphenanthera (Schisandraceae), a new 3,4-seco-lanostane triterpenoid, schisanlactone H (1), and a new monocyclofarnesane sesquiterpenoid, sphenanthin A (2), were isolated. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques.

Two new grayanane diterpenoids from the flowers of Rhododendron molle

A phytochemical investigation of the flowers of Rhododendron molle has yielded two new grayanane diterpenoids, rhodomolleins F and G (1, 2). Compounds 1 and 2 possessed an oxo-bridge between C-5 and C-9, and their structures were elucidated on the basis of interpretation of spectroscopic data, including 1D and 2D NMR techniques.

Two new oleanane triterpenoid saponins from Elsholtzia bodinieri

Two new oleanane triterpenoid saponins, bodiniosides Q (1) and R (2), along with five known saponins, niga-ichigoside F1 (3), 3-O-[β-D-glucopyranosyl]-28-O-[α-L-rhamnopyranosyl -(1→2)-β-D-glucopyranosyl] arjunolic acid (4), asiaticoside E (5), sericoside (6), and bodinioside E (7), were isolated from the aerial parts of Elsholtzia bodinieri. The structures of 1 and 2 were characterized by spectroscopic techniques and chemical evidence as 3-O-β-D- xylopyranosyl-2α, 23-dihydroxy-olean-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl- (1→2)-β-D-glucopyranoside (1) and 3-O-β-D-xylopyranosyl-2α, 23-dihydroxy-olean-12-en-28-oic acid 28-O-[β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranosyl -(1→2)]-β-D-glucopyranoside (2). Compounds 1, 3, and 5 exhibited weak anti-influenza activity against strain A/WSN/33/2009 (H1N1), with inhibition rate of 11.63%, 17.01%, and 16.98%, respectively.

Characterization of phenolic compounds from Rhododendron alutaceum.

A new phenolic glycoside, 3′-keto rhododendrin (1) and a new sesquilignan, alutaceuol (2), together with twelve known phenolic compounds, were isolated from the leaves of Rhododendron alutaceum. Their structures were elucidated by extensive spectroscopic data analysis and comparison with literature values. In addition, the detailed analysis of 2D NMR data led us to conclude that the chemical shifts of dihydrobuddlenol B (5) need to be revised.