Zheng-Hong Pan

Terpenoids and Norlignans from Metasequoia glyptostroboides

Four new terpenoids, metaseglyptorin A (1), metasequoic acid C (2), 12α-hydroxy-8,15-isopimaradien-18-oic acid (3), and (-)-acora-2,4(14),8-trien-15-oic acid (4), and three new norlignans, metasequirins D-F (5-7), were isolated from Metasequoia glyptostroboides, together with 15 known compounds. Structures of the new compounds were determined by analysis of their spectroscopic data, and the absolute configuration of 7 was established by the modified Mosher method. All of the compounds were evaluated for cytotoxicity against five human tumor cell lines.

Polycyclic polyprenylated acylphloroglucinols and chromone O-glucosides from Hypericum henryi subsp. uraloides.

Two new C(30)‐epimeric polycyclic polyprenylated acylphloroglucinols (PPAPs), named uralodins B and C (1 and 2, resp.), were isolated from the aerial parts of Hypericum henryi subsp. uraloides together with two new chromone glucosides, urachromones A and B (3 and 4, resp.), as well as 16 known compounds. Their structures were established by extensive NMR techniques and MS analysis. The epimers 1 and 2 always behaved like a single compound when examined by TLC, and were separated by HPLC. Their configuration was distinguished by comparative analysis of the NMR data with known analogues together with the ROESY experiment. All the isolated PPAPs were evaluated for their cytotoxic activities against HepG2, SGC7901, HL‐60, and K562 cell lines. Compound 1 showed modest cytotoxic activities against SGC7901 and HL‐60 cell lines, and 2 showed modest cytotoxic activities against HepG2, SGC7901, HL‐60, and K562 cell lines.

A cytotoxic cardenolide and a saponin from the rhizomes of Tupistra chinensis

A new cardenolide tupichinolide (1) and a new steroidal saponin tupichinin A (2), together with seven known compounds, were isolated from the rhizomes of Tupistra chinensis. Their structures were established using spectroscopic analysis and chemical methods. Compound 1 was the first cardenolide isolated from Tupistra chinensis and exhibited potent cytotoxicity against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480.

Terpenoids from Salvia trijuga.

Nine new germacrane sesquiterpenes, trijugins A-I (1-9), a new lupane triterpenoid, 3alpha-O-acetyl-20(29)-lupen-2alpha-ol (10), and 24 known terpenoids were isolated from Salvia trijuga. The structure of compound 1 was confirmed by single-crystal X-ray diffraction. Compounds 1-10 and 32 were evaluated for their cytotoxicity against five human tumor cell lines. Compounds 9 and 32 exhibited moderate toxicity effects against several cell lines.

New clerodane diterpenoids from the twigs and leaves of Croton euryphyllus

Three new nor-clerodane diterpenoids, crotoeurins A-C (1-3), together with four known ones were isolated from the twigs and leaves of Croton euryphyllus. Among them, crotoeurin A (1) is a new nor-clerodane diterpenoid dimer with a unique cyclobutane ring via a [2+2] cycloaddition. Their structures were elucidated by spectroscopic analyses and the stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis. Compounds 1-3 exhibited neurite outgrowth-promoting activity on NGF-mediated PC12 cells at concentration of 10μM.

Hupehenols A-E, Selective 11 beta-Hydroxysteroid Dehydrogenase Type 1 (11 beta-HSD1) Inhibitors from Viburnum hupehense

Five selective 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) competitive inhibitors, hupehenols A-E (1-5), were isolated from Viburnum hupehense. The structure elucidation indicated that compounds 1-5 are new 20,21,22,23,24,25,26,27-octanordammarane triterpenoids. Their structures were established on the basis of NMR spectroscopic and mass spectrometric analysis. Hupehenols A-E (1-5) showed inhibition against human 11β-HSD1, with hupehenols B (2) and E (5) having IC50 values of 15.3 and 34.0 nM, respectively. Moreover, hupehenols C (3) and D (4) are highly selective inhibitors of human 11β-HSD1 when compared to murine 11β-HSD1.

Vibsane-type diterpenes from leaves and twigs of Viburnum odoratissimum

Seven new vibsane-type diterpenes, vibsanols C-H (1-6) and vibsanin X (7), together with seven analogues, were isolated from the leaves and twigs of Viburnum odoratissimum. The structures of the new compounds were elucidated by extensive spectroscopic methods. All the new compounds were detected for their cytotoxicity. Compound 1 showed significant cytotoxicity against all the tested cell lines (HL-60, SMMC-7721, A-594, MCF-7, and SW-480), with IC50 values of 3.35, 4.41, 5.18, 11.30, and 3.70 μM, respectively. Compounds 4 and 5 also displayed significant cytotoxicity against hepatocellular carcinoma SMMC-7721 cell line, with IC50 values of 3.69 and 3.52 μM, respectively.

A new triterpenoid saponin from the root of Croton lachnocarpus Benth.

A new triterpenoid saponin, 3-O-β-d-xylopyranosyl spathodic acid (1), was isolated from the EtOH extract of the root of Croton lachnocarpus Benth., together with four known compounds. These compounds were characterised on the basis of their spectral data and compatible with values in the literature. Compound 1 was the first triterpenoid glucoside isolated from the genus Croton. The known compound myriaboric acid (2) showed cytotoxic activity against human hepatocellular carcinoma SMMC-7721 cell line with an IC50 value of 42.2 μM.

Norditerpenoids from Salvia castanea Diels f. pubescens

Three new norditerpenoids, castanol A-C (1-3), along with eighteen known diterpenoids, were isolated from Salvia castanea Diels f. pubescens. Their structures were elucidated by extensive spectroscopic analysis. All compounds were evaluated for their cytotoxic activities against five human cancer cell lines. The known compounds neo-tanshinlactone (12) and methyltanshinoate (17) exhibited significant cytotoxic activities against some cells.

A new daphnane diterpenoid from Excoecaria venenata with inhibitory effect on human leukaemia HL-60 cells

A new daphnane diterpenoid, venenatin (1), along with six known compounds, was isolated from the aerial parts of Excoecaria venenata. The structure of 1 was elucidated on the basis of extensive spectroscopic analysis. Compound 1 exhibited growth inhibitory effect on human leukaemia HL-60 cell line with IC50 value of 28.10 μM.