We screened natural resources for estrogen receptor (ER)-activating and bone metabolism-promoting activities with the aim of finding potential treatments for osteoporosis. A screen of 1531 extracts from Ryukyu Arc plants using a luciferase reporter assay identified an 80% MeOH extract of Scutellaria rubropunctata var. rubropunctata (SRE) with dose-dependent ER transcription-promoting activity. Importantly, SRE had no proliferative effect on human breast cancer cells. SRE enhanced the ALP activity of pre-osteoblast MC3T3-E1 cells after 72 h in culture and slightly enhanced mineralization at 14 and 21 d. SRE did not significantly affect the TRAP activity of RAW264.7 cells. Gene expression analysis in MC3T3-E1 cells by quantitative real-time PCR revealed that SRE upregulated the mRNA levels of Runx2, Osterix (Osx), Osteopontin (Opn), Osteocalcin (Ocn), Smad1, Smad4, and Smad5 at 72 h, and those of Runx2, Osx, Smad1, Smad4, and Smad5 at 21 d of osteogenic induction. Analysis of the expression levels of osteogenic markers suggested that SRE may promote osteogenic differentiation by acting at the early stage of differentiation rather than at the late stage of differentiation. These results indicate that SRE activates ER and induces osteoblast differentiation by activating Runx2 and Osx through the BMP/Smad pathway, suggesting that SRE may be useful for the prevention and treatment of postmenopausal osteoporosis.
New clerodane diterpene, 16-hydroxy-pentandralactone (1) and known diterpene acuminolide (2) were isolated from the methanol extract of Vitex cofassus leaves. The chemical structure and the absolute configuration of 1 were determined by MS, NMR and electron circular dichroism (ECD) experiments. The isolated compounds were evaluated for their antiproliferative activities against a panel of human tumor cell lines, including a multidrug-resistant (MDR) cell line. Both compounds showed potent antiproliferative activities against all the tested cell lines with IC50 values of 5.4-11.4 µM. Their effects on cell viability were also tested using vascular endothelial growth factor (VEGF)-stimulated human umbilical vein endothelial cells (HUVECs). Compound 1 inhibited VEGF-stimulated HUVEC proliferation in a dose-dependent manner. Based on these results, compound 1 could be a candidate for antitumor agent and inhibitor of angiogenesis.
Retusone A (1), a new sesquiterpene dimer consisting of two guaiane-type sesquiterpenoids, and oleodaphnal (2) were isolated from heartwood of Wikstroemia retusa (Thymelaeaceae). The planar structure of 1 was elucidated on the basis of HRESIMS and NMR spectroscopic data, and the relative stereochemistry was established by X-ray diffraction analysis. The absolute configuration of 1 was determined by electronic circular dichroism. Compound 1 suppressed luciferase reporter gene expression driven by the HBO1 (histone acetyltransferase binding to ORC1) gene promoter in human breast cancer MCF7 cells. Compound 1 also decreased the expression of endogenous HBO1 mRNA and protein, and inhibited proliferation of the cells. These results suggest that retusone A (1), which has a unique dimeric sesquiterpenoid structure with inhibitory activity against HBO1 expression, may contribute to the development of a novel therapeutic candidate for the treatment of breast cancer.
Abstract Bioassay-guided fractionation of the MeOH extract of Ephedra sinica terrestrial stems, using a PPAR-γ ligand binding assay, resulted in the isolation of 10 compounds, including one new bisabolane-type sesquiterpenoid (10). The structure of the new compound was determined by extensive spectroscopic analysis, including two-dimensional (2D) NMR. Among the isolated compounds, the sitosterol derivatives (1 and 2), flavonoid glucoside (7), and the new sesquiterpenoid (10), showed significant PPAR-γ ligand-binding activity.
Recently, Curcuma rhizome-related foods with claimed health benefits have been used worldwide; however, correct identification and quality assessment have not been conducted. Due to the wide distribution and morphological similarities of Curcuma species, the classification of some species is debated and nomenclature is inconsistent among countries. In this study, to elucidate specific molecular markers of medicinally used Curcuma species in Asia, and to solve the confusion on the reported botanical origin of crude drugs, molecular analysis based on the intron length polymorphism (ILP) in genes encoding diketide-CoA synthase and curcumin synthase and the trnK intron sequences was performed using 59 plant specimens and 42 crude drug samples from 13 Curcuma species, obtained from Asian countries. The ILP patterns of the respective species from both plant specimens and crude drug samples revealed high consistency in C. aromatica, C. zedoaria, C. phaeocaulis, C. aeruginosa, C. wenyujin, and C. zanthorrhiza, but showed intraspecies polymorphism in C. longa, C. kwangsiensis, C. amada, C. mangga and C. comosa. The C. longa specimens and samples were separated into three subgroups which were highly consistent with their geographical origins. Based on the ILP markers and the trnK intron sequences, the botanical origins of "Khamin oi" from Thailand were correctly determined to be C. longa or a hybrid between C. longa and other species, and "Wan narn kum" from Thailand and "Kasturi manjal" from India were correctly determined to be C. zanthorrhiza.
Two novel triterpene glycosides (1 and 2), 17 known triterpene glycosides (3-19), two known flavonoid glycosides (20 and 21), and two known norsesquiterpene glucosides (22 and 23) were isolated from Hedera rhombea (Araliaceae) leaves. The structures of 1 and 2 were determined by spectroscopic analysis, including two-dimensional NMR spectroscopy, and chromatographic analysis of the hydrolyzed products. The cytotoxicity of the isolated triterpene glycosides (1-19) against HL-60 human promyelocytic leukemia cells was evaluated. Compounds 9, 10, and 11 were cytotoxic to HL-60 cells with IC50 values of 7.2, 21.9, and 32.8 µM, respectively. Other compounds isolated from the leaves were not cytotoxic at sample concentrations of 50 μM.
A bioactive CH3OH–CH2Cl2 (1:1) extract of the bark of Laetia corymbulosa provided five new clerodane diterpenes with an isozuelanin skeleton, designated as corymbulosins D–H (1–5), as well as the known corymbulosins B (6) and C (7), for which the relative configurations were not previously determined. The structures of 1–5 were characterized on the basis of 1D and 2D NMR spectroscopic and HRMS analysis. The absolute configurations of all isolated compounds 1–7 were verified through chemical methods, including modified Mosher esterifications or oxidation of the hydroxy group at C-2, ECD experiments, and spectroscopic data comparison. The isolated compounds were evaluated for antiproliferative activity against a small panel of human cancer cell lines.
Six acetophenone derivatives, acronyculatins I (1), J (2), K (3), L (4), N (5), and O (6), were recently isolated from Acronychia trifoliolata, and the structure of the known acronyculatin B (7) was revised. Because of the limited quantities of isolated products as well as their structure similarity, racemic acronyculatins I-L, N, O, and B (1-7) were synthesized to confirm their structures and to obtain sufficient material for biological evaluation. Trihydroxyacetophenone was converted to the target compounds by various sequences of hydroxy group protection, allylation or prenylation, and epoxidation followed by cyclization. C-Prenylations were carried out by direct addition of a prenyl group or through 1,3- or 3,3-sigmatropic rearrangement. The synthesized racemic compounds were evaluated in an anti-tumor-promoting assay using the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All tested compounds significantly inhibited EBV-EA activation. Especially, racemic acronyculatin I (1) displayed the most potent inhibitory effects, with an IC50 value of 7.3 μM.
