Bakuchicin induces vascular relaxation via endothelium-dependent NO-cGMP signaling

Bakuchicin attenuates atopic skin inflammation

Psoralea corylifolia is a medicinal herb that provides advantageous pharmacological effects against vitiligo and skin rash. Former studies have shown that bakuchicin, a furanocoumarin compound from the fruits of P. corylifolia, has therapeutic effects against inflammation, and infection. This study aimed to define the pharmacological effects of bakuchicin on inflammatory responses and lichenification, the major symptoms of atopic dermatitis (AD). To induce AD-like skin inflammation, we exposed the ears of female BALB/c mice to 2, 4-dinitrochlorobenzene (DNCB) and Dermatophagoides farinae (house dust mite) extract (DFE) for 4 weeks. Intragastric administration of bakuchicin attenuated the symptoms of AD-like skin inflammation, as evident by reductions in ear thickness, erythema, and keratosis. Bakuchicin also reversed increases in auricular epidermal and dermal layer thicknesses, and attenuated eosinophil and mast cell infiltration in AD-induced mice. It also suppressed T_h2 gene expression as well as that of pro-inflammatory cytokines and chemokines, such as interleukin (IL)-4, IL-13, IL-31, IL-1β, IL-6, CXCL-1, and CCL-17 in the ear tissue. The levels of total and DFE-specific immunoglobulin (Ig)E, and IgG2a in the mice sera were reduced by the bakuchicin. To investigate the effect of bakuchicin on keratinocytes, experiments were performed using HaCaT cells, the representative cell type used in skin disease studies. Tumor necrosis factor-α and interferon-γ were used to activate keratinocytes. Bakuchicin suppressed T_h2 gene expression and that of pro-inflammatory cytokines and chemokines; it also suppressed STAT-1 phosphorylation and the nuclear translocation of NF-κB in activated keratinocytes. These results suggest that bakuchicin attenuated AD symptoms, thus suggesting it as a potential therapeutic agent for the treatment of AD.

General survey of Fructus Psoraleae from the different origins and chemical identification of the roasted from raw Fructus Psoraleae

Fructus Psoraleae, a traditional Chinese medicine, is widely used for preventing and treating various diseases such as vitiligo, osteoporosis and psoriasis. Coumarin, such as psoralenoside, isopsoralenoside, psoralen and isopsoralen, are important compounds in Fructus Psoraleae. In our study, ultra performance liquid chromatography coupled with diode array detector was employed for an excellent method validation for simultaneous quantification of psoralenoside, isopsoralenoside, psoralen and isopsoralen, which was further applied in performing general survey of Fructus Psoraleae from the different origins and chemical identification of the roasted from raw Fructus Psoraleae in the light of illuminating the transformed rule of psoralenoside and isopsoralenoside. There is a reciprocal relationship between (iso)psoralenoside and (iso)psoralen, and the total content remains balance in Fructus Psoraleae from the different origins. In addition, we found that (iso)psoralenoside in the powder of the raw Fructus Psoraleae could be easily transformed into (iso)psoralen in methanol aqueous solution, especially above 50% water, rather than the roasted one. Thus, we proposed a hypothesis that transformation between (iso)psoralenoside and (iso)psoralen was hindered by inactivation of β-glucosidase in the process of roasting Fructus Psoraleae, which was further verified by observing transformation of (iso)psoralenoside under the different conditions, such as temperature, pH and β-glucosidase. Therefore, we developed a feasible method to distinguish the roasted from raw Fructus Psoraleae by observing conversion from (iso)psoralenoside to (iso)psoralen in 50% methanol aqueous solution. In summary, these results pave the way for elevating quality standard for Fructus Psoraleae and distinguishing the salt-processed from raw Fructus Psoraleae.

Psoralea corylifolia extract induces vasodilation in rat arteries through both endothelium-dependent and -independent mechanisms involving inhibition of TRPC3 channel activity and elaboration of prostaglandin

CONTEXT

Fructus Psoralea, Psoralea corylifolia L. (Leguminosae), has been widely used in traditional medicines for the treatment of dermatitis, leukoderma, asthma and osteoporosis.

OBJECTIVES

In this study, we sought to study mechanisms underlying the vasoactive properties of Psoralea corylifolia extract (PCE) and its active ingredients.

MATERIALS AND METHODS

To study mechanisms underlying the vasoactive properties of PCE prepared by extracting dried seeds of Psoralea corylifolia with 70% ethanol, isometric tension recordings of rat aortic rings and the ionic currents through TRPC3 (transient receptor potential canonical 3) channels were measured with the cumulative concentration (10-600 μg/mL) of PCE or its constituents.

RESULTS

Cumulative treatment with PCE caused the relaxation of pre-contracted aortic rings in the presence and absence of endothelium with EC₅₀ values of 61.27 ± 3.11 and 211.13 ± 18.74 μg/mL, respectively. Pretreatment with inhibitors of nitric oxide (NO) synthase, guanylate cyclase, or cyclooxygenase and pyrazole 3, a selective TRPC3 channel blocker, significantly decreased PCE-induced vasorelaxation (p < 0.01). The PCE constituents, bakuchiol, isobavachalcone, isopsoralen and psoralen, inhibited hTRPC3 currents (inhibited by 40.6 ± 2.7, 27.1 ± 7.9, 35.1 ± 4.8 and 47.4 ± 3.9%, respectively). Furthermore, these constituents significantly relaxed pre-contracted aortic rings (EC₅₀ 128.9, 4.5, 32.1 and 114.9 μg/mL, respectively).

DISCUSSION AND CONCLUSIONS

Taken together, our data indicate that the vasodilatory actions of PCE are dependent on endothelial NO/cGMP and also involved in prostaglandin production. PCE and its active constituents, bakuchiol, isobavachalcone, isopsoralen and psoralen, caused dose-dependent inhibition of TRPC3 channels, indicating that those ingredients attenuate Phe-induced vasoconstriction.

Investigation of pharmacokinetic parameters of bakuchicin isolated from Psoralea corylifolia in mice

Bakuchicin is a furanocoumarin isolated from the seeds of Psoralea corylifolia, which is used in oriental medicine. However, limited information on the pharmacokinetics of bakuchicin is available and in addition, no determined method has been devised to quantify bakuchicin levels in the plasma. In the present study, we developed and validated a quantification method using liquid chromatography (LC) coupled with tandem mass spectrometry (LC-MS/MS), which was applied to a pharmacokinetic investigation in mouse plasma. LC was performed using an ACE 5 C18 column, and a mixture of acetonitrile and water containing 0.1% formic acid was used as the mobile phase at a flow rate of 220μL/min. Bakuchicin transition ions in multiple reaction-monitoring modes using positive ionization were observed at m/z 187.0 to m/z 131.0. Bakuchicin and the internal standard (reserpine) had retention times of 4.5 and 4.3min, respectively. Acceptable linearity (r²=0.996) was observed over the concentration range of 20-1000ng/mL, with a lower quantification limit of 20ng/mL in mouse plasma. This method was successfully applied to determine the pharmacokinetic parameters of bakuchicin in mouse plasma and showed that the bioavailability of bakuchicin was 58.3% at 5mg/kg oral administration.

The Chemical Constituents and Bioactivities of Psoralea corylifolia Linn.: A Review

Psoralea corylifolia Linn. (P. corylifolia) is an important medicinal plant with thousands of years of clinical application. It has been widely used in many traditional Chinese medicine formulas for the treatment of various diseases such as leucoderma and other skin diseases, cardiovascular diseases, nephritis, osteoporosis, and cancer. Phytochemical studies indicated that coumarins, flavonoids, and meroterpenes are the main components of P. corylifolia, and most of these components are present in the seeds or fruits. The extracts and active components of P. corylifolia demonstrated multiple biological activities, including estrogenic, antitumor, anti-oxidant, antimicrobial, antidepressant, anti-inflammatory, osteoblastic, and hepatoprotective activities. This paper systematically summarized literatures on the chemical constituents and biological activities of P. corylifolia, which provided useful information for the further research and development toward this potent medicinal plant.

Shengjing Capsule Improves Erectile Function Through Regulation of Nitric Oxide-induced Relaxation in Corpus Cavernosum Smooth Muscle in a Castrated Rat Model

OBJECTIVE

To evaluate the effects of Shengjing capsule on erectile function in a castrated rat model, and further to investigate the underlying molecular mechanism.

MATERIALS AND METHODS

Thirty male Sprague-Dawley rats were randomly divided into six groups (n = 5 per group), including sham group, castration group, testosterone replacement group, high-dose Shengjing capsule group, medium-dose Shengjing capsule group, and low-dose Shengjing capsule group. The weight of the body and androgen-sensitive organs, and the serum level of testosterone were assessed. Erectile function was evaluated using cavernous nerve electrical stimulation after treatment. Corpus cavernosum tissue was examined by Masson's trichrome staining, immunohistochemistry, quantitative reverse transcriptase-polymerase chain reaction, and Western blot.

RESULTS

Serum testosterone level, mean weights of body, and accessory sexual organs were not significantly different between Shengjing capsule treatment and the castration groups (P > .05 for all). Significant recovery of erectile function and the increased smooth muscle components were observed in the Shengjing capsule treatment group as compared with the castration group (P < .01 and P < .01, respectively). The gene and protein expression of 3 subtypes of nitric oxide synthase (NOS)-neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) -in cavernous tissue in Shengjing capsule-treated rats were significantly higher than in the castration group (P < .05 for all). Phosphodiesterase type 5 messenger ribonucleic acid and protein expression in each group followed a trend similar to that of smooth muscle content.

CONCLUSION

These results show that Shengjing capsule improves the erectile function by protecting the smooth muscle content and enhancing NOS activity in penile tissues of castrated male rats.

Selective Inhibition of Bakuchicin Isolated from Psoralea corylifolia on CYP1A in Human Liver Microsomes

Bakuchicin is a furanocoumarin isolated from Psoralea corylifolia and shows several biological activities. Although there have been studies on the biological effects of bakuchicin, its modulation potency of CYP activities has not been previously investigated. Here, we investigated the inhibitory effects of bakuchicin on the activities of CYP isoforms by using a cocktail of probe substrates in pooled human liver microsomes (HLMs) and human recombinant cDNA-expressed CYP. Bakuchicin strongly inhibited CYP1A-mediated phenacetin O-deethylation with an IC₅₀ value of 0.43 μM in HLMs. It was confirmed by human recombinant cDNA-expressed CYP1A1 and CYP1A2 with a K_i value of 0.11 μM and 0.32 μM, respectively. A Lineweaver-Burk plot indicated that the inhibition mechanism of bakuchicin was competitive inhibition. Overall, this is the first study to investigate the potential CYP1A1 and CYP1A2 inhibition associated with bakuchicin and to report its competitive inhibitory effects on HLMs.

High throughput screening to identify natural human monoamine oxidase B inhibitors

Age-related increase in monoamine oxidase B (MAO-B) may contribute to CNS neurodegenerative diseases. Moreover, MAO-B inhibitors are used in the treatment of idiopathic Parkinson disease as preliminary monotherapy or adjunct therapy with L-dopa. To date, meager natural sources of MAO-B inhibitors have been identified, and the relative strength, potency and rank of many plants relative to standard drugs such as Selegiline (L-deprenyl,Eldepryl) are not known. In this work, we developed and utilized a high throughput enzyme microarray format to screen and evaluate 905 natural product extracts (0.025-.7 mg/ml) to inhibit human MAO-B derived from BTI-TN-5B1-4 cells infected with recombinant baculovirus. The protein sequence of purified enzyme was confirmed using 1D gel electrophoresis-matrix assisted laser desorption ionization -time-of-flight-tandem mass spectroscopy, and enzyme activity was confirmed by [1] substrate conversion (3-mM benzylamine) to H202 and [2] benzaldehyde. Of the 905 natural extracts tested, the lowest IC50s [<0.07 mg/ml] were obtained with extracts of Amur Corktree (Phellodendron amurense), Bakuchi Seed(Cyamopsis psoralioides), Licorice Root (Glycyrrhiza glabra/uralensis), Babchi (Psoralea corylifolia seed). The data also show, albeit to a lesser extent, inhibitory properties of herbs originating from the mint family (Lamiaceae) and Turmeric, Comfrey, Bringraj, Skullcap, Kava-kava, Wild Indigo, Gentian and Green Tea. In conclusion, the data reflect relative potency information by rank of commonly used herbs and plants that contain human MAO-B inhibitory properties in their natural form.