A strategy for the rapid discovery and validation of active diterpenoids as quality markers in different habitats of Langdu using ultrahigh-performance liquid chromatography-tandem mass spectrometry with multivariate statistical analysis.

Langdu, known as a traditional Chinese medicine, was identified as the roots of species of Euphorbia ebracteolata Hayata and Euphorbia fischeriana Steud, displaying anti-tuberculosis activity. To clarify the potent quality markers of Langdu, this research first developed a fast and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry method for the quantification of 13 diterpenoids in Langdu. The developed method was further applied in the analyses of 12 authentic E. ebracteolata and E. fischeriana samples collected in northern and southeastern China. Then, the anti-tuberculosis evaluation of 12 batches of Langdu samples was performed in vitro. Finally, partial least squares discrimination analysis was used in the discrimination of E. ebracteolata and E. fischeriana from different origins and processing methods. Jolkinolide A (1), jolkinolide E (3), yuexiandajisu D (6), and ebractenone A (11) were identified as key, potent diterpenoids for the quality control of E. ebracteolata Hayata and E. fischeriana Steud. The present study established a qualitative chemical analysis method for Langdu (E. ebracteolata and E. fischeriana) and suggested the key bioactive components that will improve qualitative control methodology for this important medicine.

Lignans from Bupleurum marginatum and their antioxidant activity.

A new aryltetralin lignan, bupleroid A (1), along with ten known analogues (2-11) were isolated from Bupleurum marginatum. The structures of these isolates were determined by 1D and 2D NMR, HRESIMS, and ECD data analysis. In addition, the DPPH radical scavenging capacities of all compounds were evaluated. Compound 6 exhibited good DPPH radical scavenging activity at a concentration of 50 µM.[Formula: see text].

UV-light-driven photooxidation of harmaline catalyzed by riboflavin: Product characterization and mechanisms.

ß-Carboline alkaloid harmaline (HA) is a candidate drug molecule that has been proven to have broad and significant biological activity. Herein, the effects of HA on the riboflavin (RF)-sensitized photooxidation under aerobic conditions were studied for the first time. The photooxidation reaction of HA catalyzed by RF is triggered by UV light at 365 nm and shows a time-dependent stepwise reaction process. Seven transformed products, including five undescribed compounds, oxoharmalines A-E (1-4 and 7), and two known compounds, N-(2-(6-Methoxy-2-oxoindolin-3-yl)ethyl)acetamide (5) and harmine (6), were isolated and identified from the reaction system, following as the gradual oxidation mechanisms. The rare polymerization and dehydrogenation processes in radical-mediated photocatalytic reactions were involved in the process. The transformed products 2-7 exhibited significant neuroprotective activity in a model of H2O2-introduced injury in SH-SY5Y cells, which suggested that the products of the interaction between HA and vitamins may be beneficial to health.

Natural soluble epoxide hydrolase inhibitors from Alisma orientale and their potential mechanism with soluble epoxide hydrolase.

Inhibition of soluble epoxide hydrolase (sEH) is considered to be an effective treatment for inflammation-related diseases, and small molecules origin from natural products show promising activity against sEH. Two undescribed protostanes, 3ß-hydroxy-25-anhydro-alisol F (1) and 3ß-hydroxy-alisol G (2) were isolated from Alisma orientale and identified as new sEH inhibitors with IC50 values of 10.06 and 30.45 µM, respectively. Potential lead compound 1 was determined as an uncompetitive inhibitor against sEH, which had a Ki value of 5.13 µM. In-depth molecular docking and molecular dynamics simulations revealed that amino acid residue Ser374 plays an important role in the inhibition of 1, which also provides an idea for the development of sEH inhibitors based on protostane-type triterpenoids.

Triptolidenol, isolated from Tripterygium wilfordii, disrupted NF-κB/COX-2 pathway by targeting ATP-binding sites of IKKß in clear cell renal cell carcinoma.

Triptolidenol (TPD) is an epoxy diterpene lactone from Tripterygium wilfordii, which has been used for chronic nephritis in China，and possessed various pharmacological properties, such as anti-inflammatory and anti-cancer activities. However, the precise molecular antitumor mechanism of TPD remains to be elucidated. In this study, we investigated the effects of TPD on human clear cell renal cell carcinoma (ccRCC) and investigated its precise anti-tumor mechanisms. It was showed that TPD significantly suppressed ccRCC cell proliferation, cell migration, and induced cell cycle arrest at S phase. Furthermore, TPD also induced apoptosis by activating the cytochrome c (cyt c)/caspase cascade signaling pathway. Moreover, using confocal immunofluorescence, a dual-luciferase reporter assay and molecular docking study, the results showed that TPD obviously reduced the expression of COX-2 by inhibiting the kinase activity of IKKß via targeting its ATP-binding domain, and then attenuating the transactivation of NF-κB. Collectively, our study demonstrated that TPD suppressed renal cell carcinoma growth through disrupting NF-κB/COX-2 pathway by targeting ATP-binding sites of IKKß, and provided pharmacological evidence that TPD exhibits potential use in the treatment of COX-2-mediated diseases such as ccRCC.

Alkaloids from the nearly ripe fruits of Evodia rutaecarpa and their bioactivities.

Two novel quinolone alkaloids (1 and 2) and two novel indole alkaloids (5 and 8), together with eleven known analogues, were isolated from the nearly ripe fruits of Evodia rutaecarpa. Their structures were determined by extensive spectroscopic data, including NMR, HRESIMS, and ECD. Additionally, the anti-tumor, hypoglycemic, and anti-bacterial activities of the isolated alkaloids were evaluated in vitro. Compound 5 as a new alkaloid displayed moderate inhibitory effect against four human cancer cell lines (MCF-7 IC50 = 30.7 µM, Hepg-2 IC50 = 65.2 µM, A549 IC50 = 39.1 µM, and SHSY-5Y IC50 = 24.7 µM), α-glucosidase (IC50 = 23.9 µM) and PTP1B (IC50 = 75.8 µM). Compound 11 showed better inhibitory effect against PTP1B (IC50 = 16.2 µM) compared with that of the positive control. Compounds 5, 13, and 14 showed moderate inhibitory effects against Bacillus cereus with MIC values of 50, 25, and 10 µM, respectively.

Diterpenoids from the roots of Euphorbia fischeriana and their inhibitory effects on α-glucosidase.

Chemical investigation has been performed on the roots of Euphorbia fischeriana, a traditional Chinese medicine. Three diterpenoids were obtained using various chromatographic techniques, and their structures were determined by spectroscopic data including HRESIMS, 1D NMR, 2D NMR, ECD, and calculated ECD, which gave two new diterpenoids, daphnane type (1) and ent-pimarene type (3). Additionally, the isolated compounds (1-3) displayed moderate inhibitory effects against α-glucosidase in an in vitro bioassay.

Comparative pharmacokinetics study of five alkaloids in rat plasma and related compound-herb interactions mechanism after oral administration of Shuanghua Baihe tablets.

Shuanghua Baihe tablet is a traditional Chinese patent medicine which showed special advantages in the treatment of recurrent aphthous stomatitis. Scientists have improved and implemented the LC-MS/MS method, which is specific and sensitive, for comparative pharmacokinetics study of five alkaloids, including palmatine, berberine, epiberberine, jatrorrhizine and coptisine in rat plasma after oral administration of Rhizoma Coptidis extract and Shuanghua Baihe tablets. The results showed that Shuanghua Baihe tablets could promote the absorption of these five alkaloids and improved their bioavailability compared with R. Coptidis extract. To further investigate the related mechanism, everted intestinal sac model in vitro was used to indicate that alteration of in vivo pharmacokinetics of five alkaloids could be attributed to, at least in part, the absorption changes by coadministration of other herbs. These discoveries served as a theoretical basis for clinical use of Shuanghua Baihe tables.

Phenolic glycosides and monoterpenoids from the roots of Euphorbia ebracteolata and their bioactivities.

The bioactive substance investigation of Euphorbia ebracteolata obtained 17 compounds by various chromatographic techniques. Their structures were elucidated using widely spectroscopic data, including ESI-MS, HRESI-MS, CD, 1D- and 2D-NMR, which gave 5 new phenolic glucosides and 4 new monoterpenoids. The phenolic glucosides and monoterpenoids showed the inhibitory effect against the human carboxylesterase-2 (hCE-2) using a fluorescence bioassay in vitro, with the strongest inhibitor compound 4 (IC50 7.17µM). The antioxidant effects of these isolated compounds were evaluated using a DPPH scavenging assay. All of the phenolic acids displayed the DPPH scavenging effect, especially that eight compounds have better effect than vitamin C, with the IC50 values ranging from 4.52 to 7.52µM. Additionally, compounds 1-17 showed no cytotoxic effect against five human cancer cell lines by MTT assay.

Phenolic acids from Balanophora involucrata and their bioactivities.

The bioactive substance investigation of Balanophora involucrata obtained 15 phenolic acids, including 5 new compounds (1-3, 8, 9), which were determined by various spectroscopic data analyses. Most isolated compounds displayed inhibitory effects on α-Glucosidase in vitro. For the potential inhibitors 8 (1.95µM) and 10 (9.02µM), the inhibition kinetics have been studied, which gave the Ki values as 0.68, 3.15µM respectively. And, in silico docking analyses have been performed to investigate the inhibitory mechanism of compounds 8 and 10. Additionally, most isolated compounds showed anti-oxidant activities in the DPPH scavenging assay. New compound 8 also could inhibit the acetyl transfer activity of GlmU moderately with the IC50 value of 18.21µM, which was a new antibacterial target.

Comparative pharmacokinetic study of baicalin and its metabolites after oral administration of baicalin and Chaiqin Qingning capsule in normal and febrile rats.

An accurate, precise, selective, and sensitive high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of baicalin and its metabolite, baicalein 6-O-glucopyranuronoside, in normal and febrile rats plasma. Two analytes, along with hesperidin as an internal standard, were determined by multiple reactions monitoring (MRM) operated in the positive electrospray ionization (ESI) mode. Chromatographic separation was performed on an Agilent ZORBAX Extend-C18 column (100mm×2.10mm, 3.5µm) with a mobile phase of 0.1% formic acid solution and acetonitrile at a flow rate of 0.6mL/min. The calibration curves showed good linearity (r≥0.9974) with the concentration ranges of 2.000-2000ngmL-1 for baicalin and baicalein 6-O-glucopyranuronoside. The inter- and intra-day accuracies (relative error, RE%) were between -6.62% and 6.75%, and the precisions (relative standard deviation, RSD%) were less than 9.09% for quality control samples (QCs). The method also possessed good selectivity, recovery and stability, and was successfully applied to a comparative pharmacokinetic study of baicalin and baicalein 6-O-glucopyranuronoside in normal and febrile rats after oral administration of baicalin and Chaiqin Qingning capsule.

Inhibition of melatonin metabolism in humans induced by chemical components from herbs and effective prediction of this risk using a computational model.

BACKGROUND AND PURPOSE: Herbs which are widely used as food and medicine, are involved in many physiopathological processes. Melatonin is a human hormone, synthesized and secreted by the pineal gland, with a range of biological functions. Here, we have evaluated the potential influences of components extracted from common herbs on melatonin metabolism in humans. EXPERIMENTAL APPROACH: An in vivo pharmacokinetic study involving 12 healthy subjects, in vitro incubations with human liver microsomes (HLMs) and recombinant human cytochrome P (CYP) isoenzymes and an in silico quantitative structure-activity relationship (QSAR) model analysis using comparative molecular field analysis and comparative molecular similarity indices analysis methods were employed to explore these interactions. KEY RESULTS: After systematic screening of 66 common herbs, Angelica dahurica exhibited the most potent inhibition of melatonin metabolism in vitro. The in vivo pharmacokinetic study indicated inhibition of melatonin metabolism, with approximately 12- and 4-fold increases in the AUC and Cmax of melatonin in human subjects. Coumarins from A. dahurica, including imperatorin, isoimperatorin, phellopterin, 5-methoxypsoralen and 8-methoxypsoralen, markedly inhibited melatonin metabolism with Ki values of 14.5 nM, 38.8 nM, 6.34 nM, 5.34 nM and 18 nM respectively, through inhibition of CYP 1A2, 1A1 and 1B1 in HLMs. A QSAR model was established and satisfactorily predicted the potential risk of coumarins for inhibition of melatonin metabolism in vivo. CONCLUSION AND IMPLICATIONS: Coumarins from A. dahurica inhibited melatonin metabolism in vivo and in vitro. Our findings provide vital guidance for the clinical use of melatonin.

Drug interaction study of natural steroids from herbs specifically toward human UDP-glucuronosyltransferase (UGT) 1A4 and their quantitative structure activity relationship (QSAR) analysis for prediction.

The wide application of herbal medicines and foods containing steroids has resulted in the high risk of herb-drug interactions (HDIs). The present study aims to evaluate the inhibition potential of 43 natural steroids from herb medicines toward human UDP- glucuronosyltransferases (UGTs). A remarkable structure-dependent inhibition toward UGT1A4 was observed in vitro. Some natural steroids such as gitogenin, tigogenin, and solasodine were found to be the novel selective inhibitors of UGT1A4, and did not inhibit the activities of major human CYP isoforms. To clarify the possibility of the in vivo interaction of common steroids and clinical drugs, the kinetic inhibition type and related kinetic parameters (Ki) were measured. The target compounds 2-6 and 15, competitively inhibited the UGT1A4-catalyzed trifluoperazine glucuronidation reaction, with Ki values of 0.6, 0.18, 1.1, 0.7, 0.8, and 12.3µM, respectively. And this inhibition of steroids towards UGT1A4 was also verified in human primary hepatocytes. Furthermore, a quantitative structure-activity relationship (QSAR) of steroids with inhibitory effects toward human UGT1A4 isoform was established using the computational methods. Our findings elucidate the potential for in vivo HDI effects of steroids in herbal medicine and foods, with the clinical dr ugs eliminated by UGT1A4, and reveal the vital pharamcophoric requirement of natural steroids for UGT1A4 inhibition activity.

Liver-targeting Resibufogenin-loaded poly(lactic-co-glycolic acid)-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticles for liver cancer therapy.

Liver cancer remains a major problem around the world. Resibufogenin (RBG) is a major bioactive compound that was isolated from Chansu (also called toad venom or toad poison), which is a popular traditional Chinese medicine that is obtained from the skin secretions of giant toads. RBG has strong antitumor effects, but its poor aqueous solubility and its cardiotoxicity have limited its clinical use. The aim of this study was to formulate RBG-loaded poly(lactic-co-glycolic acid) (PLGA)-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RPTN) to enhance the treatment of liver cancer. RPTN, RBG-loaded PLGA nanoparticle (RPN), and RBG/coumarin-6-loaded PLGA-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RCPTN) were prepared. The cellular uptake of RCPTN by HepG2 and HCa-F cells was analyzed using confocal laser scanning microscopy. Apoptosis was induced in HepG2 cells by RPTN, RBG solution (RS), and 5-fluorouracil solution (used as the negative controls), as assayed using flow cytometry. LD50 (median lethal dose) values were determined for RS and RPTN, and the liver-targeting properties were determined for RCPTN in intravenously injected mice. A pharmacokinetic study was conducted in rats, and the in vivo therapeutic effects of RPTN, RPN, and RS were examined in a mouse tumor model. The results showed that RCPTN simultaneously delivered both coumarin-6 and RBG into HepG2 and HCa-F cells. The ratio of apoptotic cells was increased in the RPTN group. The LD50 for RPTN was 2.02-fold higher than the value for RS. Compared to RS, RPTN and RPN both showed a significant difference in vivo not only in the pharmacodynamic study but also in anticancer efficacy, and RPTN performed much better than RPN. The detection indexes for drug concentration and fluorescence inversion microscopy images both demonstrated that RCPTN was much better at targeting the liver than RS. The liver-targeting RPTN, which displayed enhanced pharmacological effects and decreased toxicity for the loaded drug RBG, is therefore a promising intravenous dosage form that may be useful in the treatment of liver cancer.

Identification of the hydroxylated derivatives of bufalin: phase I metabolites in rats.

Bufalin was a typical bioactive bufadienolide, existed in the traditional Chinese medicine Chan Su with the high content of 1-5%. The in vivo metabolites (1-5) of bufalin were prepared by various chromatographic techniques from the bile samples of SD rats, which were administrated with bufalin orally. Their structures were determined on the basis of the widely spectroscopic data, including HRESIMS, 1D-, and 2D NMR. And 1-3, 5 were new compounds. In the in vitro cytotoxicity assay, metabolites (1-5) showed weaker cytotoxic effects than bufalin against human cancer cell lines A549 and H1299, which indicated that the metabolism was a significant pathway for the detoxification of bufalin. Structures analyses indicated that metabolites 1-5 were hydroxylated derivatives of bufalin. This study suggested that Phase I metabolism catalyzed by CYP450 enzymes was one of the metabolic ways of bufalin, which may promote the excretion of bufalin.

Protostane Triterpenoids from the Rhizome of Alisma orientale Exhibit Inhibitory Effects on Human Carboxylesterase 2.

Twelve new and 10 known protostane triterpenoids were isolated from the rhizome of Alisma orientale. Their structures were elucidated based on physical data analyses, including UV, HRESIMS, NMR experiments ((1)H, (13)C NMR, (1)H-(1)H COSY, HSQC, HMBC, and NOESY), and induced electronic circular dichroism. New compounds 1-12 were classified as protostanes (1-10), 29-norprotostane (11), and 24-norprotostane (12) by structure analyses. Furthermore, the inhibitory effects on human carboxylesterases (hCE-1, hCE-2) of compounds 1-22 were evaluated. Compounds 2, 6, 9, and 11 showed moderate inhibitory activities and were selective toward hCE-2 enzymes, with IC50 values of 8.68, 4.72, 4.58, and 2.02 µM, respectively. The inhibition kinetics of compound 11 toward hCE-2 were established, and the Ki value was determined as 1.76 µM using a mixed inhibition model. The interaction of bioactive compound 11 with hCE-2 was shown using molecular docking.

Characterization of phase I metabolism of resibufogenin and evaluation of the metabolic effects on its antitumor activity and toxicity.

Resibufogenin (RB), one of the major active compounds of the traditional Chinese medicine Chansu, has displayed great potential as a chemotherapeutic agent in oncology. However, it is a digoxin-like compound that also exhibits extremely cardiotoxic effects. The present study aimed to characterize the metabolic behaviors of RB in humans as well as to evaluate the metabolic effects on its bioactivity and toxicity. The phase I metabolic profile in human liver microsomes was characterized systemically, and the major metabolite was identified as marinobufagenin (5ß-hydroxylresibufogenin, 5-HRB) by liquid chromatography-mass spectrometry and nuclear magnetic imaging techniques. Both cytochrome P450 (P450) reaction phenotyping and inhibition assays using P450-selective chemical inhibitors demonstrated that CYP3A4 was mainly involved in RB 5ß-hydroxylation with much higher selectivity than CYP3A5. Kinetic characterization demonstrated that RB 5ß-hydroxylation in both human liver microsomes and human recombinant CYP3A4 obeyed biphasic kinetics and displayed similar apparent kinetic parameters. Furthermore, 5-HRB could significantly induce cell growth inhibition and apoptosis in A549 and H1299 by facilitating apoptosome assembly and caspase activation. Meanwhile, 5-HRB displayed very weak cytotoxicity of human embryonic lung fibroblasts, and in mice there was a greater tolerance to acute toxicity. In summary, CYP3A4 dominantly mediated 5ß-hydroxylation and was found to be a major metabolic pathway of RB in the human liver, whereas its major metabolite (5-HRB) displayed better druglikeness than its parent compound RB. Our findings lay a solid foundation for RB metabolism studies in humans and encourage further research on the bioactive metabolite of RB.

Two new ent-kaurane diterpenoids from Pteris semipinnata.

In this study, two new compounds and six known compounds were isolated from the aerial parts of Pteris semipinnata. The chemical structures of these two new compounds were elucidated as 6ß,11α-dihydroxy-15-oxo-ent-kaur-16-en-19-oic acid (1) and 7α,11α-dihydroxy-15-oxo-ent-kaur-16-en-19-oic acid (2) by the extensive spectral methods including 2D NMR and HR-MS techniques.

Biotransformation of imperatorin by Penicillium janthinellum. Anti-osteoporosis activities of its metabolites.

Imperatorin (IMP) is a major constituent of many herbal medicines and possesses anti-osteoporosis activity. The present research work aimed to study the biotransformation processes of IMP and evaluated the anti-osteoporosis activity of the transformed metabolites. Among 18 strains of filamentous fungi screened, Penicillium janthinellum AS 3.510 exhibited good capability to metabolise IMP to the new derivatives. Ten transformed products were isolated and purified, and their structures were identified accurately based on spectroscopic data. Eight metabolites (2-8 and 10) were novel and previously unreported. The major biotransformation reactions involved hydroxylation of the prenyloxy side-chain and the lactone ring-opening reaction of furocoumarin skeleton. In addition, anti-osteoporosis activities of all products (1-10) were evaluated using MC3T3-E1 cells. The results showed that products 5 and 8 had the best bioactivities in increasing MC3T3-E1 cell growth. These products could be used in future therapeutic regimens for treating osteoporosis.