Ya-Lun Su

Bioactive carbazole alkaloids from Murraya koenigii (L.) Spreng.

Four new carbazole alkaloids (1-4) and fourteen known carbazole alkaloids (5-18) were isolated from Murraya koenigii. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 4, 6, 16, and 17 (10 μM) had moderate hepatoprotective activities against d-galactosamine-induced HL-7702 cell damage. Compounds 11, 12 and 18 showed significant PTP1B inhibitory activity with IC50 values of 1.773, 1.875 and 2.286 μM, respectively.

Hepatoprotective prenylaromadendrane-type diterpenes from the gum resin of Boswellia carterii.

Chemical examination of the exuded gum resin of Boswellia carterii resulted in the isolation of nine new prenylaromadendrane-type diterpenes, boscartols A-I (1-9). The structures of these compounds were established by extensive 1D and 2D NMR spectroscopic analyses, mass spectrometric data, and circular dichroism spectra. Compounds 1-3, 5, 6, 8, and 9 (10 μM) showed moderate hepatoprotective activity against d-galactosamine-induced HL-7702 cell damage.

Cembranoids from the Gum Resin of Boswellia carterii as Potential Antiulcerative Colitis Agents

Eight new cembranoids, boscartins A-H (1, 2, and 4-9), and the known incensole oxide were isolated from the gum resin of Boswellia carterii. The absolute configurations of 1, 2, 4, and incensole oxide were unequivocally resolved using single-crystal X-ray diffraction analysis with Cu Kα radiation, and the absolute configuration of 5 was resolved via electronic circular dichroism data. The antiulcerative colitis activities of the compounds were evaluated in an in vitro x-box-binding protein 1 (XBP 1) transcriptional activity assay using dual luciferase reporter detection. At 10 μM, compounds 1, 5, 6, and 7 significantly activated XBP 1 transcription with EC50 values of 0.34, 1.14, 0.88, and 0.42 μM, respectively, compared with the pGL3-basic vector control.

The effect of ultrasound on lipase-catalyzed regioselective acylation of mangiferin in non-aqueous solvents

A simple and efficient method for regioselective acylation of mangiferin catalyzed by lipase under ultrasound irradiation is reported. Compared with the conventional methods, its main advantages are shorter reaction time and higher yields. The optimum conditions were screened out. Under the optimal conditions (lipase: PCL, acyl donor: vinyl acetate; reaction solvent: DMSO, reaction temperature: 45°C, ultrasonic power: 200 W; substrate ratio: acyl donor/mangiferin 6/1, enzyme loading: 6 mg/ml), the regioselective acylation yield was up to 84%.

Three new phloroglucinol derivatives from Hypericum scabrum

A chemical investigation on the aerial parts of Hypericum scabrum L. resulted in the isolation of three new phloroglucinol derivatives, hyperscabrins A (1), B (2), and C (3), together with one known compound, (2R,3R,4S,6R)-3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxopropyl)-3-(4-methyl-3-pentenyl)-cyclohexanone (4). The structures were elucidated by means of spectroscopic methods, including MS, IR, 1D NMR, and 2D NMR, and the absolute configurations of chiral centers in these phloroglucinol derivatives were determined for the first time by studying their circular dichroism spectra.

Bioactive phthalides from Ligusticum sinense Oliv cv. Chaxiong

Five new phthalides (1-4, 6), two new natural products (5, 7) and five known phthalides (8-12) were isolated from the aerial parts of Ligusticum sinense Oliv cv. Chaxiong. Their structures were elucidated by HR-ESI-MS, UV, IR, 1D and 2D NMR (HSQC, HMBC, (1)H-(1)H COSY, NOESY) methods. The absolute configurations were established by the circular dichroism (CD) spectrum and the modified Moshers method. Compounds 1-8 were tested against SK-N-SH cell depriving oxygen and glucose and showed different degrees of increasing the cell survival, among which compounds 1, 4 and 8 (10 μM) showed higher cell survival than Ginsenoside Rg1.

Hepatoprotective phenolic glycosides from Gymnema tingens.

Six new phenolic diglycosides, named gymnetinosides A-F (1-6), were isolated from the ethanolic extract of Gymnema tingens, together with three known diglycosides, sequinoside K (7), khaephuoside B (8), and albibrissinoside A (9). The structures of the new compounds were determined by spectroscopic techniques including 1D-, 2D NMR, mass spectroscopy, and circular dichroism. Compounds 1, 5, and 6 showed hepatoprotective activities against D-galactosamine-induced HL-7702 cell damage.

Alkenes with antioxidative activities from Murraya koenigii (L.) Spreng.

Four new alkenes (1-4), and six known alkenes (5-12) were isolated from Murraya koenigii (L.) Spreng. Their structures were elucidated on the basis of spectroscopic analyses and references. Compounds (1-12) were evaluated for antioxidative activities. Among them, compounds 1, 2, 4, and 7 exhibited significant antioxidative activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with IC50=21.4-49.5 μM. The known compounds (5-12) were isolated from this plant for the first time.

Composition and Antioxidant Activity of the Anthocyanins of the Fruit of Berberis heteropoda Schrenk

In present study, the anthocyanin composition and content of the fruit of B. heteropoda Schrenk were determined for the first time. The total anthocyanins were extracted from the fruit of B. heteropoda Schrenk using 0.5% HCl in 80% methanol and were then purified using an AB-8 macroporous resin column. The purified anthocyanin extract (PAE) was evaluated by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and HPLC-high resolution-electrospray ionization-mass spectrometry (HPLC-HR-ESI-MS) under the same experimental conditions. The results revealed the presence of seven different anthocyanins. The major anthocyanins purified by preparative HPLC were confirmed to be delphinidin-3-O-glucopyranoside (30.3%), cyanidin-3-O-glucopyranoside (33.5%), petunidin-3-Ο-glucopyranoside (10.5%), peonidin-3-O-glucopyranoside (8.5%) and malvidin-3-O-glucopyranoside (13.8%) using HPLC-HR-ESI-MS and NMR spectroscopy. The total anthocyanin content was 2036.6 ± 2.2 mg/100 g of the fresh weight of B. heteropoda Schrenk fruit. In terms of its total reducing capacity assay, DPPH radical-scavenging activity assay, ferric-reducing antioxidant power (FRAP) assay and ABTS radical cation-scavenging activity assay, the PAE also showed potent antioxidant activity. The results are valuable for illuminating anthocyanins composition of B. heteropoda Schrenk and for further utilising them as a promising anthocyanin pigment source. This research enriched the chemical information of B. heteropoda Schrenk.

Two new polyprenylated acylphloroglucinols from Hypericum scabrum

Two new polyprenylated acylphloroglucinols, (1S,32R,5S,6R,7R)-6-((R)-3,4-di-hydroxy-4-methylpentyl)-2-(2-hydroxypropan-2-yl)-7-isobutyryl-6-methyl-5,9-bis(3-methylbut-2-en-1-yl)-4,5,6,7-tetrahydro-2H-32,7-methanocycloocta[b]furan-8,10(3H)-dione (1) and (4R,5R,7R)-4-((R)-3,4-dihydroxy-4-methylpentyl)-2,2,4-trimethyl-5,7-bis(3-methyl-but-2-en-1-yl)-7-(5-methylhex-4-enoyl)-4,5,6,7-tetrahydrobenzofuran-3(2H)-one (2) were isolated from Hypericum scabrum. The structures were elucidated by means of spectroscopic methods, including MS, IR, NMR, OR, and CD.