Yan-Tong Xu

A UPLC–MS/MS method for in vivo and in vitro pharmacokinetic studies of psoralenoside, isopsoralenoside, psoralen and isopsoralen from Psoralea corylifolia extract

ETHNOPHARMACOLOGICAL RELEVANCE The dried fruit of Psoralea corylifolia L. has been used to prevent and treat vitiligo, osteoporosis, arthralgia and asthma in Traditional Chinese Medicine for some 1600 years. Psoralen (P), isopsoralen (IP), psoralenoside (PO) and isopsoralenoside (IPO) are the major coumarins and coumarin-related benzofuran glycosides in Psoraleae Fructus, which have been reported to show estrogen-like activity, osteoblastic proliferation accelerating activity, antitumor effects and antibacterial activity. The first aim of this study is to develop a rapid, sensitive and selective ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) approach for simultaneous determination of PO, IPO, P and IP in rat plasma and samples collected from in vitro incubation experiments. The second aim is to investigate the pharmacokinetic properties of PO, IPO, P and IP after oral administration of Psoralea corylifolia extract (PCE) to rats. The third aim is to confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions. MATERIALS AND METHODS A UPLC-MS/MS method with a C18 column and a mobile phase of methanol-0.1% aqueous formic acid was validated according to the criteria in FDA guidelines about bioanalytical method, which was developed to investigate the pharmacokinetic behavior of PO, IPO, P and IP from PCE and the metabolic pathways of PO to P or IPO to IP. RESULTS The criteria for establishment of a new UPLC-MS/MS method including selectivity, linearity, accuracy, precision, extraction recovery, matrix effect and stability were validated. This method was successfully applied to the quantitative determination of PO, IPO, P and IP in biological samples collected from both in vitro incubations and in vivo rat experiments. After oral administration of PCE to rat, pharmacokinetic parameters of these four compounds indicated that in vivo biotransformation may occur between PO and P or IPO and IP. Purified benzofuran glycosides fraction (PBGF), containing only PO and IPO, was orally administered to rats to further confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions. An in vitro incubation study elucidated that PO and IPO were metabolized to P and IP by intestinal microflora through de-glucosylation. CONCLUSIONS This paper developed a rapid, sensitive and selective UPLC-MS/MS method for simultaneous determination of PO, IPO, P and IP from PCE in biological samples, and investigated on their comprehensive in vivo and in vitro pharmacokinetic studies. These obtained results showed that the metabolism by intestinal bacteria plays an important role in pharmacological effects of orally administered PCE.

Bidirectional regulation of bakuchiol, an estrogenic-like compound, on catecholamine secretion

Excess or deficiency of catecholamine (CA) secretion was related with several diseases. Recently, estrogen and phytoestrogens were reported to regulate the activity of CA system. Bakuchiol is a phytoestrogen isolated from the seeds of Psoralea corylifolia L. (Leguminosae) which has been used in Traditional Chinese medicine as a tonic or aphrodisiac. In the present study, bovine adrenal medullary cells were employed to investigate the effects and mechanisms of bakuchiol on the regulation of CA secretion. Further, its anti-depressant like and anti-stress effects were evaluated by using behavioral despair and chronic immobilization stress models. Our results indicated that bakuchiol showed bidirectional regulation on CA secretion. It stimulated basal CA secretion in a concentration dependent manner (p<0.01), while it reduced 300μM acetylcholine (ACh) (p<0.01), 100μM veratridine (Ver) (p<0.01) and 56mM K(+) (p<0.05) induced CA secretion, respectively. We also found that the stimulation of basal CA secretion by bakuchiol may act through estrogen-like effect and the JNK pathway in an extra-cellular calcium independent manner. Further, bakuchiol elevated tyrosine hydroxylase Ser40 and Ser31 phosphorylation (p<0.01) through the PKA and ERK1/2 pathways, respectively. Bakuchiol inhibited ACh, Ver and 56mM K(+) induced CA secretion was related with reduction of intracellular calcium rise. In vivo experiments, we found that bakuchiol significantly reduced immobilization time in behavioral despair mouse (p<0.05 or 0.01), and plasma epinephrine (E) and norepinephrine (NE) levels in chronic immobilization stress (p<0.05). Overall, these results present a bidirectional regulation of bakuchiol on CA secretion which indicated that bakuchiol may exert anti-stress and the potential anti-depressant-like effects.

A novel sesquiterpene and three new phenolic compounds from the rhizomes of Acorus tatarinowii Schott

A novel sesquiterpene with an unprecedented epoxy lactone skeleton, named tatarinolactone, together with two new amides, a new biphenylpropanoid and two known lignans were isolated from the rhizomes of Acorus tatarinowii Schott. Their structures were identified as 6,7,8-trihydroxy-4α-isobutyl-4,7-dimethylhexahydro-6,8α-epoxychromen-2(3H)-one (1), (E)-methyl 4-[3-(4-hydroxy-3-methoxyphenyl)acrylamido]butanoate (2), (Z)-methyl 4-[3-(4-hydroxy-3-methoxyphenyl)acrylamido]butanoate enol isomer (3), (R)-4-hydroxy-3-[1-hydroxy-3-(4-hydroxy-3-methoxyphenyl)propan-2-yl]-5-methoxybenzoic acid (4), (2S,3R)-ceplignan (5), and (2R,3S)-ceplignan (6), respectively, based on extensive spectroscopic analysis and by comparison to the known compounds. To test their effects on serotonin transporters, a high content assay using hSERT-HEK293 cell line was adopted. Results indicated that compounds 1 and 4 significantly inhibited SERT activity, while compounds 2, 3, 5, and 6 significantly enhanced SERT activity, which partly explain the traditional uses of the rhizomes of Acorus tatarinowii Schott in treatments of neuropsychiatric and digestive disorders.

Constituents from Polygonatum sibiricum and their inhibitions on the formation of advanced glycosylation end products

Abstract A new saponin, isonarthogenin 3-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (1), together with twelve known compounds, were isolated from the rhizomes of Polygonatum sibiricum. The structures of these compounds were elucidated by analysis of their 1D/2D NMR and MS data. Among them, phenol compounds 4–7 and 9–10 showed significant inhibitions against the formation of advanced glycosylation end products, with IC50 values of 0.091 ± 0.0021, 0.10 ± 0.041, 0.014 ± 0.0027, 0.11 ± 0.011, 0.13 ± 0.045, and 0.055 ± 0.019 μM, respectively. The results will promote exploiting potential medicinal use of these compounds in the prevention of diabetic complications and supporting Polygonatum sibiricum as a functional food for healthy and medicinal diet.

Novel serotonin transporter regulators: Natural aristolane- and nardosinane- types of sesquiterpenoids from Nardostachys chinensis Batal

Serotonin transporter (SERT) is a classic target of drug discovery for neuropsychiatric and digestive disorders, and against those disorders, plants of Nardostachys genus have been valued for centuries in the systems of Traditional Chinese Medicine, Ayurvedic and Unani. Herein, chemical investigation on the roots and rhizomes of Nardostachys chinensis Batal. led to the isolation of forty sesquiterpenoids including six new aristolane-type sesquiterpenoids and six new nardosinane-type sesquiterprenoids. Their structures were elucidated by extensive spectroscopic methods, combined with analyses of circular dichroism and single-crystal X-ray diffraction data. To explore natural product scaffolds with SERT regulating activity, a high-content assay for measurement of SERT function in vitro was conducted to evaluate the SERT regulating properties of these isolates. In conclusion, eleven compounds could be potential natural product scaffolds for developing drug candidates targeting SERT. Among which, kanshone C of aristolane-type sesquiterpenoid inhibited SERT most strongly, while desoxo-nachinol A of nardosinane-type sesquiterpenoid instead enhanced SERT potently.

Hawthorn (Crataegus pinnatifida Bunge) leave flavonoids attenuate atherosclerosis development in apoE knock-out mice

ETHNOPHARMACOLOGICAL RELEVANCE Hawthorn (Crataegus pinnatifida Bunge) leave have been used to treat cardiovascular diseases in China and Europe. Hawthorn leave flavonoids (HLF) are the main part of extraction. Whether hawthorn leave flavonoids could attenuate the development of atherosclerosis and the possible mechanism remain unknown. MATERIALS AND METHODS High-fat diet (HFD) mixed with HLF at concentrations of 5mg/kg and 20mg/kg were administered to apolipoprotein E (apoE) knock out mice. 16 weeks later, mouse serum was collected to determine the lipid profile while the mouse aorta dissected was prepared to measure the lesion area. Hepatic mRNA of genes involved in lipid metabolism were determined. Peritoneal macrophages were collected to study the impact of HLF on cholesterol efflux, formation of foam cell and the expression of ATP binding cassette transporter A1 (ABCA1). Besides, in vivo reverse cholesterol transport (RCT) was conducted. RESULTS HLF attenuated the development of atherosclerosis that the mean atherosclerotic lesion area in en face aortas was reduced by 23.1% (P<0.05). In mice fed with 20mg/kg HLF, Total cholesterol (TC) level was decreased by 18.6% and very low density lipoprotein cholesterol plus low density lipoprotein cholesterol (VLDLc+LDLc) level were decreased by 23.1% whereas high density lipoprotein cholesterol (HDLc) and triglyceride (TG) levels were similar compared to that of the control group. Peroxisome proliferator activated receptor alpha (PPARα) mRNA was increased by 31.2% (P<0.05) and 60.9% (P<0.05) in mice fed with 5mg/kg and 20mg/kg HLF respectively. Sterol regulatory element binding protein-1c (SREBP-1c) was decreased by 59.3% in the group of 20mg/kg. Carnitine palmitoyl transferase 1 (CPT-1) mRNA level of 20mg/kg group was induced 66.7% (P<0.05). Superoxide dismutase 1 and 2 (SOD1 and SOD2) mRNA were induced 25.4% (P<0.05) and 71.4% (P<0.05) while induced by 36.3% (P<0.05) and 73.2% (P<0.05) in group of 20mg/kg. Glutathione peroxidase 3 (Gpx3) mRNA in the group of 20mg/kg was induced by 96.7% (P<0.05). Hepatic hydroxymethylglutaryl CoA reductase (HMG-CoAR) expression was as same level as the control group while LDL receptor (LDLR) mRNA and protein were induced by 84.2% (P<0.05) and 98.8% (P<0.05) in group of 20mg/kg. HLF inhibit the formation of foam cell by 27.9% (P<0.05) in the dosage of 25μg/ml, and 33.3% (P<0.05) in the dosage of 50μg/ml. HLF increased the reverse cholesterol transport (RCT) in vivo. DISCUSSION AND CONCLUSION Hawthorn leave flavonoids can slow down the development of atherosclerosis in apoE knockout mice via induced expression of genes involved in antioxidant activities, inhibition of the foam cell formation and promotion of RCT in vivo, which implies the potential use in the prevention of atherosclerosis.

Chemical Constituents from the Flowers of Wild Gardenia jasminoides J. Ellis

Four new iridoids, 2′‐O‐(E)‐coumaroylshanzhiside (1), 6′‐O‐(E)‐coumaroylshanzhiside (2), 8α‐butylgardenoside B (3), 6α‐methoxygenipin (4), and one new phenylpropanoid glucoside, 5‐(3‐hydroxypropyl)‐2‐methoxyphenyl β‐d‐glucopyranoside (5), together with sixteen known compounds, were isolated from the edible flowers of wild Gardenia jasminoides J.Ellis. Their chemical structures were characterized by extensive spectroscopic techniques, including 1D‐ and 2D‐NMR, HR‐ESI‐MS, and CD experiments. The absolute configurations of the new isolates’ sugar moiety were assigned by HPLC analysis of the acid hydrolysates. Furthermore, the antioxidant activities of those isolates were preliminarily evaluated by DPPH scavenging experiment. And comparison of 1H‐NMR spectra for the EtOH extract of G. jasminoides J.Ellis, gardenoside B and geniposide revealed that the flowers of this plant have a considerable content of gardenoside B instead of geniposide in the fruits, indicating different activities and applications in peoples daily life.

Nardonaphthalenones A and B from the roots and rhizomes of Nardostachys chinensis Batal.

Nardonaphthalenones A and B (1-2), one new apo-α-carotenone (3) and four new monoterpenoids (4, 8-9 and 11), along with six known compounds (5-7, 10, 12-13) were isolated from the dried roots and rhizomes of Nardostachys chinensis Batal. Their structures were elucidated by analysis of the spectroscopic data including NMR, HRESIMS and circular dichroism data. Furthermore, the serotonin transporter (SERT)-regulating activities of these isolates were evaluated, among them compound 3 showed the strongest enhancement activity while compound 12 showed a moderate inhibition activity on SERT.

Dinardokanshones C–E, isonardoeudesmols A–D and nardoeudesmol D from Nardostachys jatamansi DC.

Dinardokanshones C-E, three sesquiterpenoid dimers comprising an unusual nornardosinane-type sesquiterpenoid core and an aristolane-type sesquiterpenoid unit conjugated by an extra pyran or furan ring, together with monomeric sesquiterpenoids isonardoeudesmols A-D and nardoeudesmol D, were isolated from the underground parts of Nardostachys jatamansi DC. Structures of the eight compounds were elucidated by analysis of the extensive spectroscopic data, and their absolute configurations were established by analysis of NOESY and X-ray diffraction data, combined with computational electronic circular dichroism (ECD) calculations. The results of SERT activity assay revealed that isonardoeudesmol D and nardoeudesmol D significantly inhibited SERT activity, while dinardokanshones D-E and isonardoeudesmols B-C significantly enhanced SERT activity, among which dinardokanshone D exhibited the strongest effect.