Hui-Yuan Gao

Seven new cassane furanoditerpenes from the seeds of Caesalpinia minax

A bioassay-guided study led to the isolation of seven new cassane furanoditerpenes, designated as spirocaesalmin B (1), caesalpinin M1 (2), caesalpinin M2 (3), caesalmin E1 (4), caesalmin E2 (5), caesalmin E3 (6), caesalpinin F1 (7) and three known compounds neocaesalpin A(8), neocaesalpin L(9), neocaesalpin L1(10) from the seeds of Caesalpinia minax Hance. Compound structures were determined on the basis of extensive spectroscopic analyses, including X-ray crystallographic analysis, HRESI-MS, UV, IR, 1D and 2D NMR (HSQC, HMBC, NOESY) methods. Some absolute configurations were confirmed via the circular dichroism (CD) spectra. Compound 1 is the first example of an A-seco-rearranged cassane furanoditerpene with an unusual skeleton isolated from the genus Caesalpinia. All compound inhibitory effects on influenza virus neuraminidase (NA) in vitro were valued for the first time. Compared with the positive control (Zanamivir), new compounds were found to show moderate inhibitory activity.

A new dicoumarinoid glycoside from Daphne giraldii.

A new dicoumarinoid glycoside, named giraldoid A (1), has been isolated from Daphne giraldii Nitsche. The structure of 1 was determined as 7-O-β-glucosyl-8-(7-hydroxy-2H-1-benzopyran-2-one-8-)yl-2H-1-benzopyran-2-one on the basis of chemical reactions and spectroscopic methods.

Triterpenoid saponins from Stauntonia chinensis

A new triterpenoid saponin, named stauntoside A (1) along with four known saponins (2,3,4,5) was isolated from Stauntonia chinensis DC., (Lardizabalaceae). Their structures were elucidated by spectroscopic analysis and chemical methods as 3-O-α-l-arabinopyranosyl-30-norhederagenin -28-O-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (1), 3-O-α-l-arabinopyranosyl-30- norhederagenin-28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (2), 3-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl-30-norhederagenin-28-O-α-l- rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (3), 3-O-α-l- arabinopyranosyl-hederagenin-28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d- glucopyranosyl ester (4), 3-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl-hederagenin -28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (5). The 1H and 13C NMR data for Glycoside L-G1 or Sinofoside A are paradox in the reported before. Thus, the structure elucidation of saponin 2, known as Glycoside L-G1 or Sinofoside A, was discussed and the unambiguous assignments were given.

Anti-inflammation furanoditerpenoids from Caesalpinia minax Hance

Cassane skeletons are rare in nature, but often possess valuable medicinal properties. A furanoditerpenoid with an unusual A-seco-rearranged cassane skeleton, neocaesalminin A, and five furanoditerpenoids were isolated from seeds of Caesalpinia minax Hance, along with six known cassane derivatives, 7-O-acetyl-bonducellpin C, caesalmin F, caesalmin C, ζ-caesalmin, caesalmin E1 and caesalpinin K. Compound structures were determined by spectroscopy (HR-ESI-MS, UV, IR, 1D NMR, 2D NMR), X-ray crystallography and quantum chemical computation of electronic circular dichroism). Three of the previously known compounds exhibited significant inhibition of nitric oxide production of RAW264.7 macrophages stimulated by lipopolysaccharide (LPS).

Three new cassane diterpenes from the seeds of Caesalpinia minax Hance

Three new cassane-diterpene-lactones, methyl 1α,7β-diacetoxy-5α,12α-dihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (1), methyl 7β-acetoxy-1α,5α,12α-trihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (2), and 12α-ethoxyl-1α,6α,7β-triacetoxy-5α,14β-dihydroxy-cass-13(15)-en-16,12-olide (3), were isolated from the seeds of Caesalpinia minax Hance. Their structures were established on the basis of HR-ESI-MS, 1D and 2D NMR spectral analysis.

Purine-containing cucurbitane triterpenoids from Cucurbita pepo cv dayangua

Phytochemical investigation of the fruits of Cucurbita pepo cv dayangua led to the isolation of cucurbitaglycosides A (1) and B (2). This is the first report of cucurbitane triterpenoids with a purine unit. Their structures were elucidated mainly based on interpretation of HRESIMS results, as well as 1D and 2D NMR spectra. Cucurbitaglycosides A and B showed cytotoxic activity against the human epithelial carcinoma cell line HeLa with IC50 of 17.2 and 28.4 microg/mL, respectively.

Two new lignans from Mentha spicata L

Two new lignans named spicatolignan A (1) and spicatolignan B (2) have been isolated from the whole herbs of Mentha spicata L.

Constituents from the testas of Castanea mollissima Blume with α-glucosidase inhibitory activity

In the screening of biologically active constituents from medicinal plants, the 75% EtOH extract of the testas of Castanea mollissima Blume showed potent α-glucosidase inhibitory activity. By means of various chromatographic methods, the extract gave a new dammarane-type triterpene 1 along with 17 known compounds. The structure of 1 was determined to be 3β-acetoxy-20-oxo-21-nordammaran-23-oic acid by HRMS and NMR studies including 2D NMR experiments. The new compound and some known compounds showed potent α-glucosidase inhibitory activity with acarbose as a positive control.

Two new triterpenoid saponins from Ardisia crenata

Two new triterpenoid saponins, ardisicrenoside K (1) and ardisicrenoside L (2), have been isolated from the roots of Ardisia crenata Sims. Their structures have been determined as 3β-O-{α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)]-α-l-arabinopyranosyl}-13β,28-epoxy-16-oxo-30,30-dimethoxyoleanane and 3β-O-{β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)]-α-l-arabinopyranosyl}-13β,28-epoxy-16α,20-dihydroxyoleanane by means of chemical evidences and spectral analysis. Their weak anti-fungal activity against the plant pathogenic fungus Pyricularia oryzae was evaluated in vitro.

Cucurbitane and hexanorcucurbitane glycosides from the fruits of Cucurbita pepo cv dayangua

Phytochemical investigation of the fruits of Cucurbita pepo cv dayangua has led to the isolation of two cucurbitane glycosides: cucurbitacin L 2-O-β-d-glucopyranoside (1), cucurbitacin K 2-O-β-d-glucopyranoside (2) and two hexanorcucurbitane glycosides: 2,16-dihydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 2-O-β-d-glucopyranoside (3) and 16-hydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside (4). Compounds 1, 2 and 3 were isolated from Cucurbita genus for the first time, while compound 4 is a new one. Their structures were determined on the basis of chemical and spectroscopic evidence.