Inhibition of Cytochrome P450 by Nomilin and Obacunone and Potential Mechanism in Human Liver Microsomes

Design, synthesis and bioevaluation of PI3Kα-selective inhibitors as potential colorectal cancer drugs

The dysregulation of the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin signaling pathway has been implicated in various human cancers, and isoform-selective inhibitors targeting PI3Kα have received significant interest in recent years. In this study, we have designed and synthesized three series of substituted benzoxazole derivatives based on the clinical candidate TAK-117 (8a). A detailed structure-activity relationship (SAR) study has identified the optimal compound 18a bearing a quinoxaline scaffold. Compared to the control 8a, 18a exhibited 4.4-fold more potent inhibitory activity against PI3Kα (IC50: 2.5 vs 11 nM) and better isoform-selective profiles over other PI3Ks. In addition, 18a showed a 1.5-fold more potent antiproliferative effect against HCT-116 cell lines (IC50: 3.79 vs 5.80 μM) and a better selectivity over the normal tissue cells. The potential antitumor mechanism and in vitro metabolic stability of 18a were also investigated. Notably, pharmacokinetic assays indicated that 18a had a higher plasma exposure, a higher maximum concentration and shorter elimination time compared to 8a.

The pharmacological and pharmacokinetic properties of obacunone from citrus fruits: A comprehensive narrative review

Limonoids are a class of oxygenated terpenoids that exist mainly in citrus fruits. As a kind of limonoid, obacunone has attracted more and more researchers' attention because of its extensive pharmacological activities. The purpose of the narrative review is to systematically review relevant studies on the pharmacological effects and pharmacokinetic characteristics of obacunone to provide researchers with the latest and useful information. Pharmacological studies have shown that obacunone has a variety of pharmacological activities, such as anticancer, antioxidant, anti-inflammatory, anti-diabetes, neuroprotection, antibiosis, and antivirus. Among them, the anticancer effect is the most prominent. Pharmacokinetic studies have shown that the oral bioavailability of obacunone is low. This indicates the presence of high first-pass metabolism. We hope that this paper can help relevant scholars understand the progress in pharmacological and pharmacokinetic research of obacunone and help the further development of obacunone as a functional food.

Nomilin and Its Analogues in Citrus Fruits: A Review of Its Health Promotion Effects and Potential Application in Medicine

Nomilin is one of the major limonoids, which are plant secondary metabolites also known as tetranortriterpenoids. Nomilin is found mostly in common edible citrus fruits including lemons, limes, oranges, grapefruits, mandarins, along with traditional Chinese medicines derived from citrus fruits, such as tangerine seed, tangerine peel, fructus aurantii immaturus, etc. A number of studies have demonstrated that nomilin and its analogues exhibit a variety of biological and pharmacological activities. These include anti-cancer, immune-modulatory, anti-inflammatory, anti-obesity, anti-viral, anti-osteoclastogenic, anti-oxidant, and neuro-protective effects. Thus, nomilin and its analogues have emerged as a potential therapy for human diseases. The purpose of this review is to chronicle the evolution of nomilin research from examining its history, structure, occurrence, to its pharmacological and disease-preventing properties as well as its potential utilization in medicine and food science.

Grapefruit Seed Extract Inhibits the Formation of Amyloid-like Fibrils by Trypsin in Aqueous Ethanol

Several natural compounds deriving from plants are known to be efficient anti-amyloid aggregation agents. In this study, anti-aggregation activity of grapefruit seed extract was investigated using trypsin as a model protein in aqueous ethanol at pH 7.0. Using turbidity measurement, Congo red (CR) binding assay, electronic circular dichroism (ECD) and transmission electron microscopy (TEM), we found that grapefruit seed extract has ability to inhibit trypsin amyloidlike fibril formation in vitro, and effectiveness increases with growing concentration of grapefruit seed extract. The total phenolic content of it was determined. The results showed that in addition to the polyphenolic compounds some other compounds are also responsible for the fibril formation inhibitory effect. We indicated it for the first time that limonin has anti-fibrillation effect.