Hui-Qin Chen

Triterpenes and triterpenoid saponins from the leaves of Ilex kudincha.

One new triterpene, kudinchalactone A (1), and four new triterpenoid saponins, ilekudinchosides A-D (2- 5), were isolated from the leaves of Ilex kudincha C. J. Tseng along with eight known triterpenoids. These new compounds were elucidated by spectroscopic methods including 1D and 2D NMR, HR-TOF-MS, and CD spectra. Compounds 2, 3, 12, and 13 showed antibacterial activities against Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA).

Two new antimicrobial flavanes from dragon's blood of Dracaena cambodiana

Two new flavonoids, named cambodianins D (1) and E (2), together with two known flavanes (2S)-7,4′-dihydroxy-6,8-dimethylflavane (3) and (2S)-7,3′-dihydroxy-4′-methoxy-8-methylflavane (4), were isolated from dragons blood of Dracaena cambodiana. The new compounds were determined by HR-ESI-MS and spectroscopic techniques (UV, IR, 1D, and 2D NMR). Compounds 1–3 exhibited antimicrobial activities.

A new diterpene from the stems of Trigonostemon heterophyllus

AIM To investigate the chemical constituents in the stems of Trigonostemon heterophyllus. METHOD The chemical constituents were isolated by column chromatography on silica gel, Rp-18, and Sephadex LH-20, and their structures were elucidated on the basis of spectroscopic analysis. RESULTS Three compounds were isolated and identified as a new diterpene, trigonoheterene B (1), together with two known compounds, trigonostemone (2) and trigonochinene B (3). CONCLUSION Compound 1 is new. Compounds 2 and 3 showed antibacterial activities.

Two new triterpenoid saponins from the leaves of Ilex kudingcha

Two new triterpene saponins, ilekudinchosides F (1) and G (2), along with three known saponins were isolated from the leaves of Ilex kudingcha C. J. Tseng. The new compounds were characterized as 3β,19α-dihydroxy-12α-ethoxy-urs-13(18)-ene-28,20β-lactone-3-O-[β-d-glucopyranosyl(1 → 3)]-[α-l-rhamnopyranosyl(1 → 2)]-α-l-arabinopyranoside (1) and 3β,19α-dihydroxy-12α-methoxy-urs-13(18)-ene-28,20β-lactone-3-O-[α-l-rhamnopyranosyl(1 → 2)]-α-l-arabinopyranoside (2). The new structures were elucidated by spectroscopic methods including 1D and 2D NMR, HR-TOF-MS, and CD spectrometry, and the known compounds were identified by the comparison of their NMR and HR-TOF-MS data with those reported in the literature.

Four new bi-2-(2-phenylethyl)chromone derivatives of agarwood from Aquilaria crassna

Four new bi-2-(2-phenylethyl)chromone derivatives, crassins A-D (1-4), were isolated from the EtOAc extract of agarwood originating from Aquilaria crassna. The structures including the absolute configurations of compounds were unambiguously elucidated by extensive spectroscopic methods (1D and 2D NMR, UV, ECD, IR, MS), and by comparison with the literature. The isolated compounds were tested for their acetylcholinesterase (AChE) and α-glucosidase inhibitory activities, as well as cytotoxic activities. All the compounds showed weak inhibitory activity against AChE, while compounds 3 and 4 also displayed weak cytotoxicity against human myeloid leukemia cell line (K562).

Phragmalin-type limonoids from the roots of Trichilia sinensis

Twelve new phragmalin-type limonoids, including trichisintons A–D (1–4), which contain an unusual bicyclo[5.2.14,10]decane motif in the tetranortriterpenoid core, and trisinenmalins A–C and E–I (5–7 and 10–14), together with the known compounds 15-acetyltrichagmalin C (8) and trisinenmalin D (9), were isolated from the roots of Trichilia sinensis. Their structures were determined on the basis of the analysis of MS and NMR spectroscopic data, as well as by comparison with the literature. Compounds 5–7 and 10–14 displayed weak inhibitory activity against selected tumor cell lines. Compounds 2–4, 6–9 and 12–14 exhibited weak acetylcholinesterase-inhibiting activity in vitro.

Flavonoids from artificially induced dragon's blood of Dracaena cambodiana

Dragons blood is a rare traditional medicine used in many countries. Because of its various therapeutic uses, its requirement is increasing dramatically, while formation of dragons blood need at least several years, so many researchers tried to induce the formation of dragons blood artificially, but the chemical constituents of artificially induced dragons blood were rarely studied. In our research, twenty constituents, including three new ones, were isolated from artificially induced dragons blood of Dracaena cambodiana, five of which are the same with those from natural dragons blood. In addition, six compounds exhibited cytotoxic activities, and eleven compounds demonstrated antibacterial activities. Artificially induced dragons blood is expected to be the substituent of natural dragons blood.

Mexicanolide-Type Limonoids from the Roots of Trichilia sinensis.

Four new mexicanolide-type limonoids 1–4, along with two known limonoids 5–6, were isolated from the ethanolic extracts of roots of the Traditional Chinese Medicine Trichilia sinensis. Their structures were unambiguously determined by analysis of spectroscopic data, including 1D and 2D NMR as well as MS, and by comparison with literature data. In addition, the acetylcholinesterase (AChE) inhibitory activity of compounds 1–6 was evaluated by the Ellman method. All these compounds showed weak AChE inhibitory activity, with the inhibition percentages ranging from 18.5% to 27.8%.

Dimeric sesquiterpenoid-4H-chromone derivatives from agarwood of Aquilaria crassna and their cytotoxicity

Six previously undescribed uncommon ester-bonded dimeric compounds (aquilacrassnins A-F) containing a sesquiterpenoid and a 5,6,7,8-tetrahydroxy-2-(2-phenylethyl)-5,6,7,8-tetrahydro -4H-chromone units were isolated from the EtOAc extract of agarwood originating from Aquilaria crassna. Their structures were elucidated by spectroscopic (NMR, UV, IR, MS, and ECD) methods. All the compounds were tested for AChE inhibitory activity and cytotoxicity against K562, BEL-7402, SGC-7901, Hela, and A549 tumor cell lines. The results showed that aquilacrassnin A, B, and E exhibited weak cytotoxicity against the five tested cell lines, whereas all the compounds were inactive against AChE.

Actinoplanes sediminis sp. nov., isolated from marine sediment

An actinomycete strain M4I47T was isolated from sediment from Megas Gialos, Syros, Greece. The results of phylogenetic analysis of the 16S rRNA gene sequence of M4I47T indicated that the highest similarity was with Actinoplanes atraurantiacus Y16T (98.9 %), Actinoplanes deccanensis IFO 13994T (98.8 %), Actinoplanes digitatis IFO 12512T (98.1 %) and Actinoplanes abujensis A4029T (98.0 %). The cell wall of the novel isolate contained meso-diaminopimelic acid and the whole-cell sugars were xylose, arabinose and glucose. The predominant menaquinones were MK-9(H4), MK-9(H6) and MK-9(H2). The phospholipid profile comprised phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and an unknown phospholipid. The DNA G+C content was 71.5 mol%. Furthermore, a combination of DNA-DNA relatedness and some physiological and biochemical properties indicated that the novel strain could be readily distinguished from the most closely related species. On the basis of these phenotypic and genotypic data, M4I47T represents a novel species of the genus Actinoplanes, for which the name Actinoplanessediminis sp. nov. is proposed. The type strain is M4I47T (=CCTCC AA 2016022T=DSM 100965T).