Artemisinin (ART) is an efficacious and safe anti-malarial drugs but has low oral bioavailability and auto-induction profiles during multiple dosing. The pharmacokinetic disadvantages have been found to partially depend on the induction of cytochrome P-450 enzymes by ART and resulted in the therapeutic failure due to insufficient drug levels. The present study, therefore, investigated the impacts of chrysosplenetin (CHR), a polymethoxylated flavonoid from Artemisia annua, on the pharmacokinetics and the anti-malarial efficacy of ART against Plasmodium berghei. The inhibition of CHR on enzymatic activity of CYP1A2, CYP2A, CYP2C19, CYP2D6, CYP2E1, and CYP3A in rat liver microsome was also investigated. IC50, Km, Ki, and inhibitory type of CHR were respectively calculated. Twenty rats were randomly divided into four groups and received three-day oral doses of ART in absence or presence of CHR (in ratio of 1:0, 1:1, 1:2, and 1:4, respectively). Plasma samples were separately harvested for ART pharmacokinetics analysis using a valid liquid chromatography tandem mass spectrometric (LC–MS/MS) method. Female Kunming mice were inoculated by P. berghei K173 strain and pre-exposed to three-day oral administration of ART with or without CHR as pharmacokinetics protocol. Giemsa staining method was applied to calculate percent parasitaemia (%) and inhibition (%). In vitro rat liver microsomal model was employed to elucidate the inhibitory effect of CHR on CYP1A2, CYP2A, CYP2C19, CYP2D6, CYP2E1, and CYP3A. The AUC0–t, Cmax, and t 1/2 of ART increased significantly (P < 0.05 or P < 0.01) as well as declined CLz (P < 0.05 or P < 0.01) after three-day oral doses of ART in presence of CHR (1:2) when compared with ART alone. Also, parasitaemia (%) remarkably attenuated 1.59 folds with 1.63-fold augmented inhibition (%) when the ratio between ART and CHR reached 1:2. CHR itself had no anti-malarial efficacy (P > 0.05). CHR inhibited in vitro activity of CYP1A2 and CYP2C19 (P < 0.01, IC50 = 4.61 and 6.23 μM) in a concentration–response manner. The inhibition did not emerge on CYP2E1 and CYP3A until the CHR concentration exceeded 4.0 μM (P < 0.01, IC50 = 28.17 and 3.38 µM). CHR has no impact on CYP 2A and CYP2D6 (P > 0.05). The inhibition types of CHR on CYP1A2 and CYP3A belonged to noncompetitive and uncompetitive, respectively. Co-administration of ART with CHR in ratio of 1:2 achieved a synergic anti-malarial effect partly because of the noncompetitive or uncompetitive inhibition of CHR of drug-metabolism enzymes, especially CYP3A which is closely related to the auto-induction of ART.

Celastrol (1), obtained from the roots of Tripterygium wilfordii Hook F., is most likely to become an antitumor drug, but with severe cytotoxicity. Due to the lack of modifiable sites in the structure of celastrol, the structural diversity of the modified products obtained by synthesis in the previous studies is insufficient, which hinders the pace of its patent medicine. This study describes a method of microbial transformation to increase the modification site of celastrol and reduce its toxicity. The screening of endophytes from native plants was introduced in this context, which led to two novel stereoselective oxidation products such as S-16-hydroxyl celastrol (2) and A-ring aromatized S-16-hydroxyl celastrol (3), along with a rare 7,9-octadecadienoic acid ester of celastrol (4). Their structures were determined by extensive spectroscopic data analysis, especially 1D and 2D NMR. Compared with 1, compounds 3 and 4 exhibited similar antitumor activity in U251, A549, KG-1, and B16 cell lines. Compound 2 had slightly decreased antitumor activity when compared with compound 1. Furthermore, compound 2–4 showed lower cytotoxicity against BV-2 (about 21-fold lower, 2: 92.82 μM, 3: 34.25 μM, and 4: 74.75 μM vs. celastrol: 4.35 μM), and also identical trends against H9c2 and PC12 cell lines.

This study investigated the influence of different processing methods on the oral toxicity of Sophora alopecuroides L., Fabaceae, seeds in mice and on the contents of five known toxic-effective quinolizidine alkaloids from the ethanol extracts quantified by ultra-performance liquid chromatography coupled to tandem quadrupole mass spectrometry. It provides an evidence to elucidate the possible reasons why vinegar-processing and parching methods significantly decrease the acute oral toxicity induced by S. alopecuroides and why wine-processing method increases it instead (demonstrated by measurement of LD50 and histopathological analysis). The analytical performance for the determination of the five analytes was evaluated by linearity, stability, repeatability, precision and accuracy, and recovery test. The lowest limit of quantification was determined to be 5 ng/ml for each substance and the precision and accuracy at lowest limit of quantification were below 20%. Cytisine, the most toxic alkaloid among the five alkaloids, declined 11.26, 3.98, and 2.73 folds after being vinegar-processed and fried in a ceramic or iron pan, respectively and had a very close correlation with the toxicity of S. alopecuroides seeds (r= 0.8589). Other matrine-type alkaloids with lower toxicity including matrine, sophcarpine, and sophoridine decreased after being wine-processed and fried in a ceramic pan, but increased 4.44, 7.20, and 7.23 folds when being processed by vinegar. Oxymatrine declined in all groups. It, therefore, reveals that vinegar-processing method reduces the oral toxicity of S. alopecuroides mainly due to a sharp decrease of cytisine, thus improves its clinical safety. (C) 2018 Published by Elsevier Editora Ltda. on behalf of Sociedade Brasileira de Farmacognosia.