Asprenols A-H, phenolic constituents from the stems of Ilex asprella

Modular Enantioselective Total Syntheses of the erythro-7,9-Dihydroxy- and 9-Hydroxy-7-Keto-8,4'-Oxyneolignans

A modular, enantioselective approach to access the bioactive 7,9-dihydroxy- and 9-hydroxy-7-keto-8,4'-oxyneolignans is disclosed, which employs stereoselective Mitsunobu reactions of enantiopure 2-aryl-1,3-dioxan-5-ols and functionalized phenols. The enantiopure dioxanols are prepared through Sharpless asymmetric dihydroxylation of protected coniferyl or sinapyl alcohols and subsequent benzylidene acetal formation. Through a mix-and-match coupling approach, six of the eight possible erythro-7,9-dihydroxy-8,4'-oxyneolignan enantiomeric natural products (bearing a C-1' hydroxypropyl chain) were generated following sequential deprotection. Subsequent benzylic oxidation afforded the 7-keto-derivatives, resulting in enantioselective syntheses of each enantiomer of the natural products asprenol B and icariol A1.

UPLC-Q-TOF/MS based metabolite profiling and quality marker constituents screening of root, stem and rhizome extracts of Ilex asprella

OBJECTIVE

The root of Ilex asprella (RIA) is a popular plant resource for treating inflammation-related diseases. The purpose of this study was to identify the secondary metabolites, to compare anti-inflammatory effects and to determine the quality marker components among root, stem and rhizome sections of IA.

METHODS

Chemical fingerprints of stem, root and rhizome of IA was determined by high performance liquid chromatography (HPLC). A reliable method using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was established for comprehensively determining the chemical constituents of the plants. Anti-inflammatory activities of IA and its ingredients were screened by in vivo mouse ear swelling and in vitro LPS-induced release of NO from RAW264.7 cells experiments.

RESULTS

Root, stem and rhizome of IA have shown high similarity in chemical fingerprints. Totally 149 compounds were characterized in IA, including triterpenoids, triterpenoid saponins, phenolic acids and lignans. 44 of them were identified based on co-occurring Mass2Motifs, including 19 unreported ones, whilst 17 were tentatively confirmed by comparison with reference compounds. No significant anti-inflammatory activity difference among root, stem and rhizome parts of IA was found. Ilexsaponin B2, protocatechualdehyde, isochlorogenic acid B and quinic acid, were screened out as quality marker compounds in IA.

CONCLUSION

A sensitive and rapid strategy was established to evaluate the differences on secondary metabolites of different parts of IA for the first time, and this study may contribute to the quality evaluation of medicinal herbs and provide theoretically data support for further analysis of different parts of IA.

Two new chemical constituents from the leaves of Illicium dunnianum

One new phenolic glycoside (1) and one new benzofuran derivative (2) were isolated from the leaves of Illicium dunnianum. The structures of these compounds were established by using comprehensive spectroscopic data analysis, including the 1D and 2D NMR, IR, HR-ESI-MS, electronic circular dichroism and comparison with literature data. All isolates were evaluated for the inhibition against the production of NO by LPS-stimulated RAW 264.7 macrophages.

Ionones and lignans from the fresh roots of Rehmannia glutinosa

Nine undescribed compounds, together with 21 known components, were isolated from the fresh roots of Rehmannia glutinosa. Their structures were elucidated based on spectroscopic data analysis, and the absolute configurations of undescribed compounds were determined by comparison of their calculated and experimental electronic circular dichroic (ECD) spectra and interpretation of their optical rotation data. The α-glucosidase inhibitory effects of the isolated compounds were investigated and all of them exhibited slightly inhibitory activities.

Cytochrome P450 Monooxygenase/Cytochrome P450 Reductase Bi-Enzymatic System Isolated From Ilex asprella for Regio-Specific Oxidation of Pentacyclic Triterpenoids

Ilex asprella is a plant from Aquifoliaceae. Its root is commonly used as folk medicinal materials in southern China. The chemical compositions of I. asprella are rich in pentacyclic triterpenoids, which show various biological activities and demonstrate a good prospect for drug development. The elucidation of biosynthesis mechanism of triterpenoids in I. asprella could lay important foundations for the production of these precious plant secondary metabolites by metabolic engineering. Our previous studies have revealed IaAO1 (a CYP716A210 homolog) responsible for the C-28 oxidation of α- and β-amyrin. Herein, we reported the identification of three more cytochrome P450 monooxygenase genes IaAO2 (a CYP716A212 homolog), IaAO4 (CYP714E88), IaAO5 (CYP93A220), and a cytochrome P450 reductase gene IaCPR by using Saccharomyces cerevisiae eukaryotic expression system and gas chromatography-mass spectrometry. Among them, the protein encoded by IaAO2 can catalyze the C-28 oxidation of α-amyrin and β-amyrin, IaAO4 can catalyze the C-23 oxidation of ursolic acid and oleanolic acid, while IaAO5 is responsible for the C-24 oxidation of β-amyrin. By introducing three genes IaAO1, IaAO4 and IaCPR into S. cerevisiae. We constructed an engineered yeast strain that can produce C-23 hydroxyl ursane-type triterpenoid derivatives. This study contributes to a thorough understanding of triterpenoid biosynthesis of medicinal plants and provides important tools for further metabolic engineering.

Ten new glycosides, carissaedulosides A-J from the root barks of Carissa edulis and their cytotoxicities

Ten previously undescribed glycosides, carissaedulosides A-J (1-10) referring to six apiosylated phenylpropanoids (1-6), one coumarin-secoiridoid hybrid (7), and three furofuran lignans (8-10) were isolated from the root barks of Carissa edulis, together with 13 known analogues (11-23). Their structures were elucidated by spectroscopic analysis, ECD computational methods, and chemical derivations for configurations of sugar moieties. The new lignan bisdesmoside, 10, exhibited significant cytotoxicity against A549 (IC₅₀ = 3.87 ± 0.03 μM) and MCF-7 (IC₅₀ = 9.231 ± 0.290 μM) cell lines, while the known lignan monodesmoside, 12, showed impressive cytotoxic efficacy (IC₅₀ = 5.68 ± 0.180 μM) against only MCF-7 cell line. It is noted that a known cardenolide, 11, displayed strong cytotoxic potency against HL-60, A549, MCF-7 and SW480 cell lines with IC₅₀ values ranging from 0.023 to 0.137 μM. Moreover, compound 11 induced dose-dependent apoptosis on SW480 cell, but not explicit dose-dependent apoptosis on HL-60 cells.