Inhibitory effect of tanshinones on rat CYP3A2 and CYP2C11 activity and its structure-activity relationship

Reassessing the molecular structures of some previously isolated abietane diterpenoids with a naphthalene moiety and the structure-activity relationship (SAR) of quinone diterpenoids

Crystals of previously described para-naphthoquinone abietane diterpenoids 12,16-dideoxy-aegyptinone B and 12-deoxy-salvipisone were obtained from Zhumeria majdae Rech.f. & Wendelbo. However, single-crystal X-ray diffraction analysis followed by reinterpretation of their NMR data revealed that their structures require revision, and they should be revised to the two ortho-naphthoquinones, zhumerianone C and aethiopinone, respectively. Interestingly, a further search through literature revealed that there were more of such cases, in which differentiation between the ortho-/para-orientation had not been carried out correctly in the structure elucidation of naphthalene containing abietane diterpenoids. Therefore, in the current study, we pointed out some 1D and 2D NMR generalizations that would help the unambiguous deduction of the ortho-/para-orientation of naphthalene containing abietanes and revised the structure of some previously described compounds accordingly. Based on these generalizations, structures of sibiriquinones A and B, sahandinone, and sahandone were revised to the known structures 1,2-didehydromiltirone, miltirone, saprorthoquinone, and sahandone B, respectivelyand tebesinone B, arucadiol, and sahandol II were revised to three undescribed structures. It was also proposed that structures of palmitoyl arucadiol and compounds with the salvifolane skeleton need revision. Furthermore, these structure revisions shed light on the structure-activity relationship of the quinone diterpenoids, approving that the ortho-quinone is the critical structural component for cytotoxicity in these compounds.

Insights into oral bioavailability enhancement of therapeutic herbal constituents by cytochrome P450 3A inhibition

Herbal plants typically have complex compositions and diverse mechanisms. Among them, bioactive constituents with relatively high exposure in vivo are likely to exhibit therapeutic efficacy. On the other hand, their bioavailability may be influenced by the synergistic effects of different bioactive components. Cytochrome P450 3A (CYP3A) is one of the most abundant CYP enzymes, responsible for the metabolism of 50% of approved drugs. In recent years, many therapeutic herbal constituents have been identified as CYP3A substrates. It is more evident that CYP3A inhibition derived from the herbal formula plays a critical role in improving the oral bioavailability of therapeutic constituents. CYP3A inhibition may be the mechanism of the synergism of herbal formula. In this review, we explored the multiplicity of CYP3A, summarized herbal monomers with CYP3A inhibitory effects, and evaluated herb-mediated CYP3A inhibition, thereby providing new insights into the mechanisms of CYP3A inhibition-mediated oral herb bioavailability.

Tanshinone IIA exerts therapeutic effects by acting on endogenous stem cells in rats with liver cirrhosis

BACKGROUND AND OBJECTIVE

Liver cirrhosis (LC), the major pathway for the progression and development of chronic liver disease, is an advanced stage of liver disease. It is the third most common chronic noncommunicable disease after cardiovascular diseases and malignant tumors. Tanshinone IIA (Tan), an extract of Salvia miltiorrhiza (S. miltiorrhiza), has been proven to promote the proliferation and differentiation of stem cells. Moreover, its protective effect in liver injury has received widespread attention. The present study investigated whether Tan plays a therapeutic role in LC by promoting endogenous stem cell proliferation and differentiation.

MATERIALS AND METHODS

LC models were established by intraperitoneal injection of an olive oil solution containing 50 % carbon tetrachloride (CCL₄) combined with 10 % alcohol in the drinking water. After successful model establishment, the animals were randomly divided into four groups and injected with physiological saline or low-, medium-, or high-dose (10, 20, or 40 mg/kg) Tan for seven consecutive days. The protective effect of Tan on LC was observed by western blotting, serological examination and histopathological staining. Furthermore, immunofluorescence double-labeling of 5-bromo-2-deoxyuridine (BrdU) and the liver cell markers albumin and CK-18 or the liver stem cell markers EPCAM and OV-6 was used to evaluate the proliferation and differentiation of endogenous liver stem cells.

RESULTS

We confirmed successful establishment of the LC model by observing transaminase levels and hematoxylin-eosin (HE) and Masson staining of liver sections in CCL₄-treated and healthy rats. After Tan treatment, HE and Masson staining of paraffin sections of liver tissue showed that Tan treatment significantly improved histological injury to the liver. Serological tests showed that albumin-bilirubin (ALBI) scores and models for end-stage liver disease (MELD) were lower. Immunofluorescence and immunohistochemical staining showed that the newly proliferated cells were colocalized with ALB, OV-6, EPCAM, and CK-18, indicating that new expression of these markers occurred after Tan injection. All results were most significant in the medium-dose treatment group.

CONCLUSION

Tan can alleviate liver injury induced by CCL₄ combined with alcohol in rats and plays a therapeutic role in LC by promoting the proliferation and differentiation of endogenous liver stem cells.

Meta-Analysis on the Efficacy and Safety of Traditional Chinese Medicine as Adjuvant Therapy for Refractory Androgenetic Alopecia

Objective

Traditional Chinese medicine (TCM) therapies have been widely used for the treatment of androgenetic alopecia (AGA) for thousands of years. We conducted a meta-analysis to evaluate the curative efficacy and safety of TCM for treating AGA.

Methods

Randomized controlled trials (RCTs) of TCM for the treatment of AGA through March 2019 were systematically identified in 4 English databases, namely, PubMed, Cochrane Library, EMBASE, and Web of Science, and 4 Chinese databases, namely, Sino-Med, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and WanFang. Quality assessment and data analysis were performed by Review Manager 5.3.5, and Stata 15.1 was used to cope with publication bias.

Results

30 RCTs involving 2615 patients were randomly divided into a TCM group and a conventional medicine (CM) group. The results showed that the total efficacy rate (TER) of the TCM group was significantly higher than that of the control group (OR = 3.34, 95% CI = 2.75–4.05, P < 0.00001). The total symptom score (TSS) of the TCM group was markedly reduced when compared with the CM group (SMD = −0.86; 95% CI = −1.19, −0.53; P < 0.00001). The microelement levels (Fe²⁺, Zn²⁺, and Cu²⁺) in hair were significantly improved when complemented with TCM therapy. In addition, no significant differences were observed between the two groups in terms of adverse events (OR = 0.55, 95% CI = 0.29–1.05, P=0.07).

Conclusions

In view of the effectiveness and safety of TCM, the present meta-analysis suggests that TCM could be recommended as an effective and safe adjuvant therapy for the treatment of AGA by improving the TER, symptoms, serum testosterone levels, and microelement levels. However, long-term and higher-quality RCTs are needed to overcome the limitations of the selected studies and more precisely interrogate the efficacy and safety of TCM.

Dihydroisotanshinone I combined with radiation inhibits the migration ability of prostate cancer cells through DNA damage and CCL2 pathway

BACKGROUND

Radiotherapy plays an important role in the treatment of prostate cancer. Despite that sophisticated techniques of radiotherapy and radiation combined with chemotherapy were applied to the patients, some tumors may recur. Therefore, the study investigated the effect of dihydroisotanshinone I (DT) and the combination treatment of 5 μM DT and 5Gy irradiation (IR) against the migration ability of prostate cancer cells.

METHODS

DT and the combination treatment were studied for its biological activity against migration ability of prostate cancer cells with transwell migration assay. Subsequently, we tried to explore the underlying mechanism with ELISA, flow cytometry and Western's blotting assay.

RESULTS

The results showed that DT and the combination treatment substantially inhibited the migration ability of prostate cancer cells. DT and the combined treatment can decrease the ability of macrophages to recruit prostate cancer cells. Mechanistically, DT and the combination treatment reduced the secretion of chemokine (C-C Motif) Ligand 2 (CCL2) from prostate cancer cells. We also found that DT treatment induced the cell cycle of prostate cancer cells entering S phase and increased the protein expression of DNA damage response proteins (rH2AX and phosphorylated ataxia telangiectasia-mutated [ATM]) in DU145 cells and PC-3 cells.

CONCLUSIONS

DT displays radiosensitization and antimigration effects in prostate cancer cells by inducing DNA damage and inhibiting CCL2 secretion. We suggest that DT can be used as a novel antimetastatic cancer drug or radiosensitizer in the armamentarium of prostate cancer management.

Influence of Shenxiong Glucose Injection on the Activities of Six CYP Isozymes and Metabolism of Warfarin in Rats Assessed Using Probe Cocktail and Pharmacokinetic Approaches

Shenxiong glucose injection (SGI), a traditional Chinese medicine (TCM) preparation, has been widely used for the treatment of various cardiovascular and cerebrovascular diseases for many years. We assessed the potential influences of SGI on the activities of six CYP enzymes (CYP1A2, CYP2C11, CYP2C19, CYP2D4, CYP2E1, and CYP3A2) and on the pharmacokinetics of warfarin in rats. We compared plasma pharmacokinetics of six probe drugs (caffeine/CYP1A2, tolbutamide/CYP2C11, omeprazole/CYP2C19, metoprolol/CYP2D4, chlorzoxazone/CYP2E1, and midazolam/CYP3A2) and of warfarin between control and SGI-pretreated groups, to estimate the effect on the relative activities of the six isozymes and warfarin metabolism. There were no significant differences in the pharmacokinetic parameters of caffeine, omeprazole, metoprolol, chlorzoxazone, and midazolam between the SGI-pretreated and control groups. However, many pharmacokinetic parameters of tolbutamide in SGI-pretreated rats were affected significantly (p < 0.05), and indicated tolbutamide metabolism in the former group was markedly slower. Moreover, SGI reduced the clearance of warfarin. These results suggested SGI showed no effects on the enzyme activities of rat CYP1A2, CYP2C19, CYP2D4, CYP2E1, and CYP3A2, but inhibited the enzyme activity of CYP2C11, and improved the blood concentration of warfarin. This suggests that the dose of warfarin may need be adjusted when co-administrated with SGI.

IN VIVO EFFECT OF RUTA CHALEPENSIS EXTRACT ON HEPATIC CYTOCHROME 3A1 IN RATS

Background:

Since the time when drugs began to be used, it became evident that they could produce a therapeutic effect, but also a clinical condition of toxicity or no effect at all on humans, despite using the same doses in different patients. Such untoward effects were termed “drug idiosyncrasy” and also “idiosyncratic drug effects”, but the factors producing such diverse responses were never taken into account.

Materials and Methods:

Ruta chalepensis L. (fringed rue) is an herbaceous plant of the Rutaceae family used in traditional medicine due to its properties, such as its analgesic and antipyretic effects. This study used 25 male rats divided into five groups. Plant extract was administered to Groups 1 and 2 at doses of 100 and 30 mg/kg/day, respectively, for three days; Group 3 was administered 100 mg/kg/day of dexamethasone (DEX), as well as 100 mg/kg/day of Ruta chalepensis extract; Group 4 was administered 100 mg/kg/day of DEX and treated as positive control; Group 5 was treated as negative control and was administered a physiological solution. Twenty-four hours after the the last dose, the animals were sacrificed and their livers were extracted.

Results:

The aqueous extract of Ruta chalepensis, intraperitoneally administered, was able to induce cytochrome 3A1 in doses of 30 mg/kg/day, and a greater inducing effect occurs when the plant is co-administered in doses of 100 mg/kg/day with dexamethasone.

Conclusion:

This study suggests that aqueous extract of Ruta chalepensis can induce cytochrome 3a1. This study helps provide a better understanding of CYP3a regulation. Future in vitro work is needed to determine the compounds that produce the cytochrome modulation.

Danshen improves survival of patients with advanced lung cancer and targeting the relationship between macrophages and lung cancer cells

In traditional Chinese medicine, Salvia miltiorrhiza Bunge (danshen) is widely used in the treatment of numerous cancers. However, its clinical effort and mechanism in the treatment of advanced lung cancer are unclear. In our study, the in vivo protective effort of danshen in patients with advanced lung cancer were validated using data from the National Health Insurance Research Database in Taiwan. We observed in vitro that dihydroisotanshinone I (DT), a bioactive compound in danshen, exerts anticancer effects through many pathways. First, 10 μM DT substantially inhibited the migration ability of lung cancer cells in both macrophage and macrophage/lung cancer direct mixed coculture media. Second, 10 μM DT repressed the phosphorylation of signal transducer and activator of transcription 3 (STAT3), the protein expression of S-phase kinase associated protein-2 (Skp2), and the mRNA levels of STAT3-related genes, including chemokine (C–C motif) ligand 2 (CCL2). In addition, 10 μM DT suppressed the macrophage recruitment ability of lung cancer cells by reducing CCL2 secretion from both macrophages and lung cancer cells. Third, 20 μM DT induced apoptosis in lung cancer cells. Furthermore, DT treatment significantly inhibited the final tumor volume in a xenograft nude mouse model. In conclusion, danshen exerts protective efforts in patients with advanced lung cancer. These effects can be attributed to DT-mediated interruption of the cross talk between lung cancer cells and macrophages and blocking of lung cancer cell proliferation.

Selective in vitro and in silico butyrylcholinesterase inhibitory activity of diterpenes and rosmarinic acid isolated from Perovskia atriplicifolia Benth. and Salvia glutinosa L

Cholinesterase inhibition is one of the most treatment strategies against Alzheimer's disease (AD) where metal accumulation is also strongly associated with pathology of the disease. In the current study, we assessed inhibitory effect against acetyl- (AChE) and butyrylcholinesterase (BChE) and metal-chelating capacity of twelve diterpenes: arucadiol, miltirone, tanshinone IIa, 1-oxomiltirone, cryptotanshinone, 1,2-didehydromiltirone, 1,2-didehydrotanshinone IIa, 1β-hydroxycryptotanshinone, 15,16-dihydrotanshinone, tanshinone I, isotanshinone II, 1(S)-hydroxytanshinone IIa, and rosmarinic acid, isolated from Perovskia atriplicifolia and Salvia glutinosa. The compounds were tested at 10 μg/mL using ELISA microtiter assays against AChE and BChE. QSAR and molecular docking studies have been also performed on the active compounds. All of the compounds showed higher [e.g., IC50 = 1.12 ± 0.07 μg/mL for 1,2-didehydromiltirone, IC50 = 1.15 ± 0.07 μg/mL for cryptotanshinone, IC50 = 1.20 ± 0.03 μg/mL for arucadiol, etc.)] or closer [1,2-didehydrotanshinone IIa (IC50 = 5.98 ± 0.49 μg/mL) and 1(S)-hydroxytanshinone IIa (IC50 = 5.71 ± 0.27 μg/mL)] inhibition against BChE as compared to that of galanthamine (IC50 = 12.56 ± 0.37 μg/mL), whereas only 15,16-dihydrotanshinone moderately inhibited AChE (65.17 ± 1.39%). 1,2-Didehydrotanshinone IIa (48.94 ± 0.26%) and 1(S)-hydroxytanshinone IIa (47.18 ± 5.10%) possessed the highest metal-chelation capacity. The present study affords an evidence for the fact that selective BChE inhibitors should be further investigated as promising candidate molecules for AD therapy.

Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), a natural naphthoquinone compound isolated from roots of Plumbago zeylanica L., has drawn a lot of attention for its plenty of pharmacological properties including antidiabetes and anti-cancer. The aim of this study was to investigate the effects of plumbagin on CYP1A2, CYP2B1/6, CYP2C9/11, CYP2D1/6, CYP2E1 and CYP3A2/4 activities in human and rat liver and evaluate the potential herb-drug interactions using the cocktail approach. All CYP substrates and their metabolites were analyzed using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Plumbagin presented non-time-dependent inhibition of CYP activities in both human and rat liver. In humans, plumbagin was not only a mixed inhibitor of CYP2B6, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, but also a non-competitive inhibitor of CYP1A2, with Ki values no more than 2.16 μM. In rats, the mixed inhibition of CYP1A2 and CYP2D1, and competitive inhibition for CYP2B1, CYP2C11 and CYP2E1 with Ki values less than 9.93 μM were observed. In general, the relatively low Ki values of plumbagin in humans would have a high potential to cause the toxicity and drug interactions involving CYP enzymes.

Investigation of cytochrome P450 inhibitory properties of maslinic acid, a bioactive compound from Olea europaea L., and its structure-activity relationship

Maslinic acid (MA), the main pentacyclic triterpene of Olea europaea L. fruit, possesses a variety of pharmacological actions, including hypoglycemic, antioxidant, cardioprotective and antitumoral activities. Despite its importance, little is known about its effects on the cytochrome P450 (CYP) activity in both humans and animals. Therefore, the aim of this study was to investigate the effects of MA on the CYP 1A2, 2C9/11, 2D1/6, 2E1 and 3A2/4 activities by human and rat liver microsomes and specific CYP isoforms. In humans, MA only weakly inhibited CYP3A4 activity in human liver microsomes and specific CYP3A4 isoform with IC50 value at 46.1 and 62.3µM, respectively. In rats, MA also exhibited weak inhibition on CYP2C11, CYP2E1 and CYP3A2 activities with IC50 values more than 100µM. Enzyme kinetic studies showed that the MA was not only a competitive inhibitor of CYP3A4 in humans, but also a competitive inhibitor of CYP2C11 and 3A2 in rats, with Ki of 18.4, 98.7 and 66.3µM, respectively. Moreover, the presence of hydroxyl group at C-2 position of triterpenic acid in MA compared with oleanolic acid could magnify its competitive inhibition on human CYP3A4 activity. The relatively high Ki values of MA would have a low potential to cause the possible toxicity and drug interactions involving CYP enzymes, thus suggesting a sufficient safety for its putative use as a nutraceutical taken together with drugs.

Enzyme kinetic and molecular docking studies for the inhibitions of miltirone on major human cytochrome P450 isozymes

Previous studies have shown that major tanshinones isolated from Danshen (Salvia miltiorrhiza) inhibited human and rat CYP450 enzymes-mediated metabolism of model probe substrates, with potential in causing herb-drug interactions. Miltirone, another abietane type-diterpene quinone isolated from Danshen, has been reported for its anti-oxidative, anxiolytic and anti-cancer effects. The aim of this study was to study the effect of miltirone on the metabolism of model probe substrates of CYP1A2, 2C9, 2D6 and 3A4 in pooled human liver microsomes. Miltirone showed moderate inhibition on CYP1A2 (IC(50)=1.73 μM) and CYP2C9 (IC(50)=8.61 μM), and weak inhibition on CYP2D6 (IC(50)=30.20 μM) and CYP3A4 (IC(50)=33.88 μM). Enzyme kinetic studies showed that miltirone competitively inhibited CYP2C9 (K(i)=1.48 μM), and displayed mixed type inhibitions on CYP1A2, CYP2D6 and CYP3A4 with K(i) values of 3.17 μM, 24.25 μM and 35.09 μM, respectively. Molecular docking study further confirmed the ligand-binding conformations of miltirone in the active sites of these human CYP450 isoforms, and provided some information on structure-activity relationships for the CYPs inhibition by tanshinones. Taken together, CYPs inhibitions of miltirone were weaker than dihydrotanshinone, but stronger than cryptotanshinone, tanshinone I and tanshinone IIA.

Tanshinones: sources, pharmacokinetics and anti-cancer activities

Tanshinones are a class of abietane diterpene compound isolated from Salvia miltiorrhiza (Danshen or Tanshen in Chinese), a well-known herb in Traditional Chinese Medicine (TCM). Since they were first identified in the 1930s, more than 40 lipophilic tanshinones and structurally related compounds have been isolated from Danshen. In recent decades, numerous studies have been conducted to investigate the isolation, identification, synthesis and pharmacology of tanshinones. In addition to the well-studied cardiovascular activities, tanshinones have been investigated more recently for their anti-cancer activities in vitro and in vivo. In this review, we update the herbal and alternative sources of tanshinones, and the pharmacokinetics of selected tanshinones. We discuss anti-cancer properties and identify critical issues for future research. Whereas previous studies have suggested anti-cancer potential of tanshinones affecting multiple cellular processes and molecular targets in cell culture models, data from in vivo potency assessment experiments in preclinical models vary greatly due to lack of uniformity of solvent vehicles and routes of administration. Chemical modifications and novel formulations had been made to address the poor oral bioavailability of tanshinones. So far, human clinical trials have been far from ideal in their design and execution for the purpose of supporting an anti-cancer indication of tanshinones.

Molecular docking and enzyme kinetic studies of dihydrotanshinone on metabolism of a model CYP2D6 probe substrate in human liver microsomes

The effects of Danshen and its active components (tanshinone I, tanshinone IIA, dihydrotanshinone and cryptotanshinone) on CYP2D6 activity was investigated by measuring the metabolism of a model CYP2D6 probe substrate, dextromethorphan to dextrorphan in human pooled liver microsomes. The ethanolic extract of crude Danshen (6.25-100 μg/ml) decreased dextromethorphan O-demethylation in vitro (IC(50)=23.3 μg/ml) and the water extract of crude Danshen (0.0625-1 mg/ml) showed no inhibition. A commercially available Danshen pill (31.25-500 μg/ml) also decreased CYP2D6 activity (IC(50)=265.8 μg/ml). Among the tanshinones, only dihydrotanshinone significantly inhibited CYP2D6 activity (IC(50)=35.4 μM), compared to quinidine, a specific CYP2D6 inhibitor (IC(50)=0.9 μM). Crytotanshinone, tanshinone I and tanshinone IIA produced weak inhibition, with IC(20) of 40.8 μM, 16.5 μM and 61.4 μM, respectively. Water soluble components such as salvianolic acid B and danshensu did not affect CYP2D6-mediated metabolism. Enzyme kinetics studies showed that inhibition of CYP2D6 activity by the ethanolic extract of crude Danshen and dihydrotanshinone was concentration-dependent, with K(i) values of 4.23 μg/ml and 2.53 μM, respectively, compared to quinidine, K(i)=0.41 μM. Molecular docking study confirmed that dihydrotanshinone and tanshinone I interacted with the Phe120 amino acid residue in the active cavity of CYP2D6 through Pi-Pi interaction, but did not interact with Glu216 and Asp301, the key residues for substrate binding. The logarithm of free binding energy of dihydrotanshinone (-7.6 kcal/mol) to Phe120 was comparable to quinidine (-7.0 kcal/mol) but greater than tanshinone I (-5.4 kcal/mol), indicating dihydrotanshinone has similar affinity to quinidine in binding to the catalytic site on CYP2D6.