Potent Inhibition of Human Cytochrome P450 3A4 by Biflavone Components from Ginkgo Biloba and Selaginella Tamariscina.

CYP3A4-mediated Phase I biotransformation is the rate-limiting step of elimination for many commonly used clinically agents. The modulatory effects of herbal medicines on CYP3A4 activity are one of the risk factors affecting the safe use of drug and herbal medicine. In the present study, the inhibitory effects of nearly hundred kinds of herbal medicines against CYP3A4 were evaluated based on a visual high-throughput screening method. Furthermore, biflavone components including bilobetin (7-demethylginkgetin, DGK), ginkgetin (GK), isoginkgetin (IGK), and amentoflavone (AMF) were identified as the main inhibitory components of Ginkgo biloba L. (GB) and Selaginella tamariscina (P. Beauv.) Spring (ST), which displayed very strong inhibitory effects toward CYP3A4. The inhibitory effects of these biflavones on clinical drugs that mainly undergo CYP3A4-dependent metabolism were evaluated. The IC 50 of GK toward tamoxifen, gefitinib and ticagrelor were found to be of 0.478 ± 0.003, 0.869 ± 0.001, and 1.61 ± 0.039 µM, respectively. These results suggest the potential pharmacokinetic interactions between the identified biflavones and clinical drugs undergoing CYP3A4-mediated biotransformation. The obtained information is important for guiding the rational use of herbal medicine in combination with synthetic pharmaceuticals.

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.

A natural inhibitor from Alisma orientale against human carboxylesterase 2: Kinetics, circular dichroism spectroscopic analysis, and docking simulation.

As a part of our searching for natural human carboxylesterase 2 (human CES 2) inhibitors from traditional Chinese medicine, we found that the extract of Alisma orientale significantly inhibited human CES 2 in vitro. The investigation on A. orientale led to the isolation of a new protostane-type triterpenoid alismanin I (1). Its structure was determined according to HRESIMS, 1D and 2D NMR spectra. Alismanin I (1) displayed significantly inhibitory activity against human CES 2 with IC50 value of 1.31 ±â€¯0.09 µM assayed by human CES 2-mediated DDAB hydrolysis. According to its inhibition kinetic result, compound 1 was a noncompetitive type inhibitor, and its Ki was 3.65 µM. Its inhibitory effect was confirmed in living cell level through a visual manner. The potential interaction mechanism of compound 1 with human CES 2 was also analyzed by circular dichroism (CD) spectrum and molecular docking.

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.

Effect of Alkaloids Isolated from Phyllodium pulchellum on Monoamine Levels and Monoamine Oxidase Activity in Rat Brain.

Phyllodium pulchellum (P. pulchellum) is a folk medicine with a significant number of bioactivities. The aim of this study was to investigate the effects displayed by alkaloids fractions, isolated from the roots of P. pulchellum, on neurotransmitters monoamine levels and on monoamine oxidase (MAO) activity. Six alkaloids, which had indolealkylamine or ß-carboline skeleton, were obtained by chromatographic technologies and identified by spectroscopic methods such as NMR and MS. After treatment with alkaloids of P. pulchellum, the reduction of DA levels (54.55%) and 5-HT levels (35.01%) in rat brain was observed by HPLC-FLD. The effect of alkaloids on the monoamines metabolism was mainly related to MAO inhibition, characterized by IC50 values of 37.35 ± 6.41 and 126.53 ± 5.39 µg/mL for MAO-A and MAO-B, respectively. The acute toxicity indicated that P. pulchellum extract was nontoxic.

[Chemical Constituents of the Aerial Parts from Plumbago zeylanica].

Objective: To study the anti-oxidative constituents of the aerial parts of Plumbago zeylanica. Methods: The ethanol extract of Plumbago zeylanica was separated and purified by various chromatographic techniques. On the basis of various spectroscopic data, the structures of isolated compounds were elucidated. ABTS+radical scavenging were carried out in antioxidant activity evaluation of the isolated compounds. Results: Eleven compounds were isolated and identified as cis-isoshinanolone-4-O-ß-D-glucopyranoside( 1),tachioside( 2),2,6-dimethoxy-p-hydroquinone-1-O-ß-D-glucopyranoside( 3),3-( ß-D-glucopyranosyloxy)-4-methoxybenzoic acid( 4),3'-O-ß-D-glucopyranosyloxy-plumbagic acid( 5),3'-O-ß-D-glucopyranosyloxy-plumbagic acid methyl ester( 6),plumbagic acid( 7),plumbagine A( 8),plumbagine C( 9),syringate-4-O-ß-D-glucopyranoside( 10) and 2-methyl-5-hydroxychromone( 11). Compounds 2,3,and5 displayed significant scavenging effect on ABTS+. Conclusion: Compounds 1 ~ 4,10,11 are obtained from this plant for the first time. Compounds 2,3,and 5 show significant anti-oxidative effects.

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.

Bioactive metabolites of Schisanlactone E transformed by Cunninghamella blakesleana AS 3.970.

Schisanlactone E (SE) is a major triterpene obtained from the plants of genus Kadsura. The aim of this research was to investigate the transformed metabolites of SE by fungi and evaluate the bioactivities of these products. After screening 10 strains of filamentous fungi, Cunninghamella blakesleana AS 3.970 was chosen as a potent organism to be used for the biotransformation of SE. 13 metabolites were obtained and determined to be new compounds through the use of spectroscopic data, including UV, 1D-, 2D-NMR, and HR-ESIMS. Furthermore, in an in vitro bioassay, metabolites 7 and 9 showed moderate inhibitory effects on the nitric oxide production in LPS-induced macrophages with IC50 values of 16.73, 5.91 µM, respectively; 9 could inhibit the proliferation of acetaldehyde-induced HSC-T6 cells, with the IC50 value of 21.4 µM. Preliminary findings on the structure-activity relationships for these metabolites were also discussed.

Phenolic constituents from the roots of Phyllodium pulchellum.

Three new phenolic constituents 1-3 were obtained from the 95% ethanol extract of the roots of Phyllodium pulchellum (Leguminosae). Their structures were elucidated on the basis of spectroscopic analyses, such as NMR, UV, IR, HR-ESI-MS, and CD. Furthermore, in an in vitro bioassay, all compounds were tested for inhibitory effects against the proliferation of acetaldehyde-stimulated HSC-T6 cells, and compound 3 exhibited potent inhibitory activity with the IC50 value of 7.6 µM.

Quercetin: a potential natural drug for adjuvant treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA) is the rheumatism mainly manifested as disabling joint disease and mainly involves hands, wrists, feet and other small joints. Recurrent arthritis attacks, synovial cell hypertrophy and hyperplasia and bone and cartilage damages eventually lead to joint dysfunction and other complications, and there is no cure. Quercetin (QU) is a kind of natural flavonoids, with lipid-lowering, anti-inflammatory and other pharmacological activities, and minor toxic side effects. Thus, we assume that QU may be an adjuvant natural drug for treatment of RA. The possible mechanism is through regulation of NF-κB, to inhibit the transcription of joint synovitis factors, hinder the generation of inflammatory factors, and inhibit the inflammatory reaction; through inhibiting the activities of VEGF, bFGF, MMP-2 and other cytokines, to inhibit angiogenesis in multiple links and inhibit synovial pannus formation. QU may be an adjuvant natural drug for treatment of RA.

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.

Simultaneous quantification of seven major bufadienolides in three traditional Chinese medicinal preparations of chansu by HPLC-DAD.

A high-performance liquid chromatographic method was applied to the determination of gamabufotalin, telocinobufagin, bufotalin, cinobufotalin, bufalin, cinobufagin and resibufogenin in three traditional Chinese medicinal preparations containing ChanSu. The compounds were separated on a YMC-C18 column (250 x 4.6 mm, 5 um) with a gradient of acetonitrile and 0.3% aqueous acetic acid (v/v) at a flow rate of 0.8 mL min(-1) and detected at 296 nm. Complete separation was obtained within 35 min for the seven bufadienolides. The calibration curves showed good linearity (r2 > 0.999) within the test range. The recovery was 95.5% - 105.9%. The assay could simultaneously determine seven major bufadienolides of the three Chinese medicinal preparations of ChanSu in 35 min. The results obtained suggested that the developed HPLC assay could be comprehensively utilized for the quality control of the three traditional Chinese medicinal preparations of ChanSu used in the clinic.