Humulus lupulus L. extract and its active constituent xanthohumol attenuate oxidative stress and nerve injury induced by iron overload via activating AKT/GSK3ß and Nrf2/NQO1 pathways.

Hops, the dried female clusters from Humulus lupulus L., have traditionally been used as folk medicines for treating insomnia, neuralgia, and menopausal disorders. However, its pharmacological action on iron overload induced nerve damage has not been investigated. This study aims to evaluate the protective effects of hops extract (HLE) and its active constituent xanthohumol (XAN) on nerve injury induced by iron overload in vivo and in vitro, and to explore its underlying mechanism. The results showed that HLE and XAN significantly improved the memory impairment of iron overload mice, mainly manifested as shortened latency time, increased crossing platform times and spontaneous alternation ratio, and increased the expression of related proteins. Additionally, HLE and XAN significantly increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, and remarkably decreased malondialdehyde (MDA) level in hippocampus. Also, HLE and XAN apparently reduced reactive oxygen species (ROS) content of PC12 cells induced by iron dextran (ID), and improved the oxidative stress level. Moreover, HLE and XAN significantly upregulated the expression of nuclear factor E2-related factor (Nrf2), NAD(P)H quinone oxidoreductase (NQO1), heme oxygenase-1 (HO-1), SOD, phosphorylated AKT (p-AKT), and phosphorylated GSK3ß (p-GSK3ß) both in hippocampus and PC12 cells. These findings demonstrated the protective effect of HLE and XAN against iron-induced memory impairment, which is attributed to its antioxidant profile by activation of AKT/GSK3ß and Nrf2/NQO1 pathways. Also, it was suggested that hops could be a potential candidate for iron overload-related neurological diseases treatment.

Humulus lupulus L. Extract Prevents Ovariectomy-Induced Osteoporosis in Mice and Regulates Activities of Osteoblasts and Osteoclasts / 中国结合医学杂志

OBJECTIVE@#To systematically evaluate the protective effects of Humulus lupulus L. extract (HLE) on osteoporosis mice.@*METHODS@#In vivo experiment, a total of 35 12-week-old female ICR mice were equally divided into 5 groups: the sham control group (sham); the ovariectomy with vehicle group (OVX); the OVX with estradiol valerate [EV, 0.2 mg/(kg•d)] the OVX with low- or high-dose HLE groups [HLE, 1 g/(kg•d) and 3 g/(kg•d)], 7 in each group. Treatment began 1 week after the ovariectomized surgery and lasted for 12 weeks. Bone mass and trabecular bone mircoarchitecture were evaluated by micro computed tomography, and bone turnover markers in serum were evaluated using enzyme-linked immunosorbent assay (ELISA) kits. In vitro experiment, osteoblasts and osteoclasts were treated with HLE at doses of 0, 4, 20 and 100 µg/mL. Biomarkers for bone formation in osteoblasts and bone resorption in osteoclasts were analyzed.@*RESULTS@#Compared with the OVX group, HLE exerted bone protective effects by the increase of estradiol (P<0.05), the improvement of cancellous bone structure, bone mineral density (P<0.01) and the reduction of serum alkaline phosphatase (ALP), tartrate resistant acid phosphatase (TRAP), bone gla-protein, c-terminal telopeptides of type I collagen (CTX-I) and deoxypyridinoline levels (P<0.01 for all). In vitro experiment, compared with the control group, HLE at 20 µg/mL promoted the cell proliferation (P<0.01), and increased the expression of bone morphogenetic protein-2 and osteopontin levels in osteoblasts (both P<0.05). HLE at 100 µg/mL increased the osteoblastic ALP activities, and HLE at all dose enhanced the extracellular matrix mineralization (both P<0.01). Furthermore, compared with the control group, HLE at 20 µg/mL and 100 µg/mL inhibited osteoclastic TRAP activity (P<0.01), and reduced the expression of matrix metalloproteinase-9 and cathepsin K (both P<0.05).@*CONCLUSION@#HLE may protect against bone loss, and have potentials in the treatment of osteoporosis.

Study on exosite inhibitor of cathepsin K from Herba Ecliptae fractions / 药学学报

Cathepsin K (CTSK) is considered a critical pharmaceutical target in the treatment of osteoporosis. CTSK exerts proteolytic activities against regulatory proteins besides its collagenase function, which may account for some of the adverse reactions when blocked by active site-directed inhibitors. Exosite inhibitors that can discriminate between the therapeutic collagenase and other biological activities of CTSK specifically inhibit the collagenase activity of CTSK without interfering with the other proteolytic activities of the protease. Active recombinant CTSK was expressed in Pichia pastoris, and purified by n-butyl sepharose and SP sepharose column chromatography. Herba Ecliptae is a common traditional Chinese medicine in the treatment of bone diseases. Collagenase assay and benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin (Z-FR-MCA) substrate assay based on CTSK are applied to verify the exosite inhibitors. n-Butanol extract of Herba Ecliptae are the most active fraction and eclalbasaponin IX isolated from n-butanol fraction is the potential exosite inhibitor of CTSK.

Estrogenic activity of osthole and imperatorin in MCF-7 cells and their osteoblastic effects in Saos-2 cells / 中国天然药物

There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy (HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase (ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor (PR) and PS2 mRNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.

A rapid and sensitive liquid chromatography-tandem mass spectrometric method for determination of actinoside E in rat plasma and application to a pharmacokinetic study / 中国天然药物

A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of actinoside E in rat plasma. The analytes were extracted by ethyl acetate and an analogue of actinoside F was used as the internal standard. The mobile phase consisted of methanol-water (50: 50, V/V) containing 0.1% formic acid was delivered at a flow rate of 0.3 mL·min(-1) to a Zorbax SB-C18 column (100 mm × 2.1 mm, 3.5 μm). The detection was performed by electrospray ionization mass spectrometry in the negative multiple reaction monitoring mode with a chromatograph run time of 3.0 min. Calibration curves of actinoside E were linear in the range of 0.5-2 500 ng·mL(-1). In this range, intra- and inter-day precision ranged from 1.7% to 7.5% and 2.0% to 8.9%, respectively. The accuracy ranged from 95.7% to 108.6%, and extraction recovery from 83.2% to 85.5%. This method was successfully applied to a pharmacokinetic study of actinoside E in rats after intravenous (5 mg·kg(-1)) and oral (100 mg·kg(-1)) administration, and the results showed that actinoside E was poorly absorbed with an absolute bioavailability being approximately 0.27%.