(-)-Catechin-7-O-ß-d-Apiofuranoside Inhibits Hepatic Stellate Cell Activation by Suppressing the STAT3 Signaling Pathway.

Hepatic fibrosis is characterized by the abnormal deposition of extracellular matrix (ECM) proteins. During hepatic fibrogenesis, hepatic stellate cell (HSC) activation followed by chronic injuries is considered a key event in fibrogenesis, and activated HSCs are known to comprise approximately 90% of ECM-producing myofibroblasts. Here, we demonstrated that (-)-catechin-7-O-ß-d-apiofuranoside (C7A) significantly inhibited HSC activation via blocking the signal transducer and activator of transcription 3 (STAT3) signaling pathway. This is the first study to show the hepatic protective effects of C7A with possible mechanisms in vitro and in vivo. In our bioactivity screening, we figured out that the EtOH extract of Ulmusdavidiana var. japonica root barks, which have been used as a Korean traditional medicine, inhibited collagen synthesis in HSCs. Four catechins isolated from the EtOAc fraction of the EtOH extract were compared with each other in terms of reduction in collagen, which is considered as a marker of hepatic protective effects, and C7A showed the strongest inhibitory effects on HSC activation in protein and qPCR analyses. As a possible mechanism, we investigated the effects of C7A on the STAT3 signaling pathway, which is known to activate HSCs. We found that C7A inhibited phosphorylation of STAT3 and translocation of STAT3 to nucleus. C7A also inhibited expressions of MMP-2 and MMP-9, which are downstream genes of STAT3 signaling. Anti-fibrotic effects of C7A were evaluated in a thioacetamide (TAA)-induced liver fibrosis model, which indicated that C7A significantly inhibited ECM deposition through inhibiting STAT3 signaling. C7A decreased serum levels of aspartate amino transferase and alanine transaminase, which were markedly increased by TAA injection. Moreover, ECM-associated proteins and mRNA expression were strongly suppressed by C7A. Our study provides the experimental evidence that C7A has inhibitory effects on HSC activation after live injury and has preventive and therapeutic potentials for the management of hepatic fibrosis.

Effects of ß-Sitosterol from Corn Silk on TGF-ß1-Induced Epithelial-Mesenchymal Transition in Lung Alveolar Epithelial Cells.

Pulmonary fibrosis is a chronic lung disease characterized by abnormal accumulation of the extracellular matrix (ECM). Chronic damage of the alveolar epithelium leads to a process called "epithelial-mesenchymal transition" (EMT) and increases synthesis and deposition of ECM proteins. Therefore, inhibition of EMT might be a promising therapeutic approach for the treatment of pulmonary fibrosis. ß-Sitosterol is one of the most abundant phytosterols in the plant kingdom and the major constituent in corn silk, which is derived from the stigma and style of maize (Zea mays). In this study, we elucidated that ß-sitosterol inhibited transforming growth factor-ß1 (TGF-ß1)-induced EMT and consequently had an antifibrotic effect. ß-Sitosterol (1-10 µg/mL) significantly downregulated the TGF-ß1-induced fibrotic proteins, such as collagen, fibronectin, and α-smooth muscle actin in human alveolar epithelial cells (p < 0.01). After 24 h, relative wound density (RWD) was increased in TGF-ß1 treated group (82.16 ± 5.70) compare to the control group (64.63 ± 2.21), but RWD was decreased in ß-sitosterol cotreated group (10 µg/mL: 71.54 ± 7.39; 20 µg/mL: 65.69 ± 6.42). In addition, the changes of the TGF-ß1-induced morphological shape and protein expression of EMT markers, N-cadherin, vimentin, and E-cadherin, were significantly blocked by ß-sitosterol treatment (p < 0.01). The effects of ß-sitosterol on EMT were found to be associated with the TGF-ß1/Snail pathway, which is regulated by Smad and non-Smad signaling pathways. Taken together, these findings suggest that ß-sitosterol can be used to attenuate pulmonary fibrosis through suppression of EMT by inhibiting the TGF-ß1/Snail pathway.

ß-Peltoboykinolic Acid from Astilbe rubra Attenuates TGF-ß1-Induced Epithelial-to-Mesenchymal Transitions in Lung Alveolar Epithelial Cells.

Epithelial-to-mesenchymal transition (EMT) is increasingly recognized as contributing to the pathogenesis of idiopathic pulmonary fibrosis. Therefore, novel plant-based natural, active compounds have been sought for the treatment of fibrotic EMT. The aim of the present study was to investigate the inhibitory effects of Astilbe rubra on TGF-ß1-induced EMT in lung alveolar epithelial cells (A549). A. rubra was subjected to extraction using 70% ethanol (ARE), and ethanol extracts of the aerial part and that of the rhizome were further partitioned using various solvents. Protein expression and cell motility were investigated to evaluate the inhibitory effects of ARE on EMT. EMT occurred in A549 cells treated with TGF-ß1, but was prevented by co-treatment with ARE. The dichloromethane fractions showed the strongest inhibitory effect on TGF-ß1-induced EMT. ß-Peltoboykinolic acid was isolated from the dichloromethane fractions of A. rubra by activity-oriented isolation. ß-Peltoboykinolic acid not only attenuated TGF-ß1-induced EMT, but also the overproduction of extracellular matrix components including type I collagen and fibronectin. The Smad pathway activated by TGF-ß1 was inhibited by co-treatment with ß-peltoboykinolic acid. Taken together, these results indicate that ß-peltoboykinolic acid from A. rubra and dichloromethane fractions shows potential as an antifibrotic agent in A549 cells treated with TGF-ß1.

Ginkgo biloba extract EGb 761-mediated inhibition of aromatase for the treatment of hormone-dependent breast cancer.

Ginkgo biloba has been used in herbal medicines for thousands of years. Although a standard G. biloba extract, EGb 761 has been used to improve cognition in breast cancer patients, its effects on breast cancer are unknown. Therefore, we investigated the antitumorigenic effects of EGb 761 using an in vitro cell model and an in vivo xenograft model. EGb 761 significantly inhibited aromatase activity in aromatase over-expressing MCF-7 cells (MCF-7 AROM). In addition, EGb 761 exposure reduced cytochrome p450 aromatase (CYP19) mRNA and protein expression; CYP19 promoter I.3 and PII expression particularly decreased. These inhibitory effects on aromatase were accompanied by reduced 17ß-estradiol levels in MCF-7 AROM cells. For elucidating antitumorigenic effects, MCF-7 AROM cells were implanted in BALB/c nude mice prior to oral EGb 761 treatment for 3 weeks. EGb 761 reduced the tumor size and significantly reduced tumor CYP19 mRNA expression. Taken together, our results indicated that EGb 761 inhibited aromatase and exerted antitumor effects on breast cancer cells both in vitro and in vivo. These findings suggest that EGb761 may be a useful aromatase inhibitor for the treatment for estrogen-sensitive breast cancer.

Ethanolic extract of dandelion (Taraxacum mongolicum) induces estrogenic activity in MCF-7 cells and immature rats.

Plants of the genus Taraxacum, commonly known as dandelions, are used to treat breast cancer in traditional folk medicine. However, their use has mainly been based on empirical findings without sufficient scientific evidence. Therefore, we hypothesized that dandelions would behave as a Selective estrogen receptor modulator (SERM) and be effective as hormone replacement therapy (HRT) in the postmenopausal women. In the present study, in vitro assay systems, including cell proliferation assay, reporter gene assay, and RT-PCR to evaluate the mRNA expression of estrogen-related genes (pS2 and progesterone receptor, PR), were performed in human breast cancer cells. Dandelion ethanol extract (DEE) significantly increased cell proliferation and estrogen response element (ERE)-driven luciferase activity. DEE significantly induced the expression of estrogen related genes such as pS2 and PR, which was inhibited by tamoxifen at 1 µmol·L(-1). These results indicated that DEE could induce estrogenic activities mediated by a classical estrogen receptor pathway. In addition, immature rat uterotrophic assay was carried out to identify estrogenic activity of DEE in vivo. The lowest concentration of DEE slightly increased the uterine wet weight, but there was no significant effect with the highest concentration of DEE. The results demonstrate the potential estrogenic activities of DEE, providing scientific evidence supporting their use in traditional medicine.

Inhibitory Aromatase Effects of Flavonoids from Ginkgo Biloba Extracts on Estrogen Biosynthesis.

Ginkgo biloba extract (GBE) is a popular phytomedicine and has been used for disorders of the central nervous system, cardiovascular, renal, respiratory, and circulatory diseases. Although GBE is a complex mixture of over 300 compounds, its major components are 24% flavonoids and 6% terpene lactones. In this study, we tested the inhibitory effects of the three major flavonoids (kaempferol, quercetin, and isorhamnetin) from GBE, independently and as mixtures, on aromatase activity using JEG-3 cells (human placental cells) and recombinant proteins (human placental microsome). In both systems, kaempferol showed the strongest inhibitory effects among the three flavonoids; the flavanoid mixtures exerted increased inhibitory effects. The results of exon I.1-driven luciferase reporter gene assays supported the increased inhibitory effects of flavonoid mixtures, accompanied by suppression of estrogen biosynthesis. In the RT-PCR analysis, decreased patterns of aromatase promoter I.1 mRNA expressions were observed, which were similar to the aromatase inhibition patterns of flavonoids and their mixtures. The present study demonstrated that three flavonoids synergistically inhibit estrogen biosynthesis through aromatase inhibition, decrease CYP19 mRNA, and induce transcriptional suppression. Our results support the usefulness of flavonoids in adjuvant therapy for breast cancer by reducing estrogen levels with reduced adverse effects due to estrogen depletion.

Chemopreventive effects of Ginkgo biloba extract in estrogen-negative human breast cancer cells.

Excessive level of estrogen is considered as a main cause of breast cancer, therefore, many studies have focused on estrogen receptor (ER)-positive breast cancer, even though ER-negative cancer has a poor prognosis than ER-positive breast cancer. We evaluated the anti-cancer effects of Ginkgo biloba extract (GBE) in estrogen-independent breast cancer. GBE has been traditionally used as a platelet activating factor, a circulatory stimulant, a tonic, and anti-asthmatic drug, and anti-cancer agent. However, anti-cancer effects of GBE on ER-negative breast cancer have not been proved yet. In this study, we tested chemotherapeutic potential of GBE in the MDA-MB-231 (ER-negative) human breast cancer cell line. Our results showed that cytotoxicity effects of GBE in MDA-MB-231 lead to DNA fragmentation at high concentrations (500 and 1,000 µg/ml). Caspase-3 was significantly activated and mRNA levels of apoptosis-related genes (Bcl-2 and Bax) were altered. These results indicate that GBE induces apoptosis in MDA-MB-231 cells. It is presumed that GBE has chemopreventive effects in ER-independent breast cancer through anti-proliferation and apoptosis-inducing activities.

Effects of ginkgo biloba on in vitro osteoblast cells and ovariectomized rat osteoclast cells.

Ginkgo biloba extract (GBE) has a selective estrogen receptor modulator (SERM)-like biphasic effect on estrogen, and could be a potential alternative to hormone replacement therapy (HRT). Here, we investigated whether GBE can ameliorate estrogen-depleted osteoporosis in in vitro osteoblast cells and in estrogen-deprived ovariectomized (OVX) rats, a classical animal model for postmenopausal osteoporosis. GBE (50-150 microg/mL) significantly increased ALP (Alkaline phosphatase) activity of osteoblast cells, indicating that GBE promotes osteoblast mineralization. OVX rats exposed to GBE (100 and 200 mg/kg/day, oral treatment), raloxifene (3 mg/kg/day, oral treatment) or estradiol (E2, 10 microg/kg/day, subcutaneous injection) decreased osteoclast resorptive activity compared with OVX rats. GBE and raloxifene did not increase uterine weight compared with OVX rats, while E2 and Sham control did, suggesting that GBE has no uterotrophic activity, which is a disadvantage of estrogen therapy. In OVX rats, GBE did not restore severe bone density loss induced by OVX, indicating that GBE may be insufficient as therapeutic material for severe osteoporosis. However, despite its no effects on bone density loss in OVX rats, GBE did stimulate osteoblast differentiation and antiosteoclastic activity in vitro. Therefore, GBE may have preventive potential on osteoporosis as do other phytoestrogens.