Rosemary extract (RE) is an approved food preservative in the European Union and contains dietary phytochemicals that are beneficial for gastrointestinal health. This study investigated the effects of RE on dextran sodium sulfate (DSS)-induced colitis and also determined the pharmacokinetics of dietary phytochemicals administered to mice via oral gavage. Individual components of rosemary extract were separated and identified by LC–MS/MS. The pharmacokinetics of two major diterpenes from RE, carnosic acid (CA) and carnosol (CL), administered to mice via oral gavage were determined. Then, the effect of RE pre-treatment on the disease activity index (DAI) of DSS-induced colitis in mice was investigated. The study determined that 100 mg/kg RE significantly improved DAI in DSS-induced colitis compared to negative control. Sestrin 2 protein expression, which increased with DSS exposure, was reduced with RE treatment. Intestinal barrier integrity was also shown to improve via fluorescein isothiocyanate (FITC)–dextran administration and Western blot of zonula occludens-1 (ZO-1), a tight junction protein. Rosemary extract was able to improve the DAI of DSS-induced colitis in mice at a daily dose of 100 mg/kg and showed improvement in the intestinal barrier integrity. This study suggests that RE can be an effective preventative agent against IBD.

Bergamot, a Mediterranean citrus fruit native to southern Italy, has been reported to have cholesterol-lowering properties; however, the mechanism of action is not well understood. Due to structural similarities with 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibitors, it has been proposed that the phenolic compounds in bergamot may also inhibit HMGCR. Statins are widely used for their cholesterol-lowering properties; however, they are not universally well tolerated, suggesting there is a need to identify novel cholesterol-lowering strategies. In the present study, we investigated bergamot fruit extract (BFE) and its principal components (neoeriocitrin, naringin, neohesperidin, melitidin, and brutieridin) for their ability to regulate cholesterol levels in HepG2 and Caco-2 cells. BFE at increasing concentrations decreased the levels of total and free cholesterol in HepG2 cells. BFE and its constituents did not directly inhibit HMGCR activity. However, BFE and neohesperidin decreased HMGCR levels in HepG2 cells, suggesting that neohesperidin and BFE may downregulate HMGCR expression. An increase in AMP-kinase phosphorylation was observed in BFE and neohesperidin-treated cells. In Caco-2 cells, brutieridin exhibited a significant reduction in cholesterol uptake and decreased the level of Niemann-Pick C1 Like 1, an important cholesterol transporter. Taken together, our data suggest that the cholesterol-lowering activity of bergamot is distinct from statins. We hypothesize that BFE and its principal constituents lower cholesterol by inhibiting cholesterol synthesis and absorption.

A major limitation of current prostate cancer pharmacotherapy approaches is the inability of these compounds to target androgen receptor variants or mutants that develop during prostate cancer progression. The demand for novel therapeutics to prevent, slow, and treat prostate cancer is significant because FDA approved anti-androgens are associated with adverse events and can eventually drive drug-resistant prostate cancer. This study evaluated α-mangostin for its novel ability to degrade the androgen receptor and androgen receptor variants. α-Mangostin is one of more than 70 isoprenylated xanthones isolated from Garcinia mangostana that we have been evaluating for their anticancer potential. Prostate cancer cells treated with α-mangostin exhibited decreased levels of wild-type and mutated androgen receptors. Immunoblot, immunoprecipitation, and transfection experiments demonstrated that the androgen receptor was ubiquitinated and subsequently degraded via the proteasome, which we hypothesize occurs with the assistance of BiP, an ER chaperone protein that we have shown to associate with the androgen receptor. We also evaluated α-mangostin for its antitumor activity and promotion of androgen receptor degradation in vivo. In summary, our study demonstrates that androgen receptor degradation occurs through the novel activation of BiP and suggests a new therapeutic approach for prostate cancer.

Background/Objectives: Xanthones from the tropical fruit mangosteen (Garcinia mangostana) have been reported to modulate oxidative stress and inflammatory responses. This work explored the anti-inflammatory potential of mangosteen in the form of tinctures. Methods: Tinctures were prepared from the pericarp and leaves, characterized for their major constituents, and evaluated for their in vitro, anti-inflammatory and antioxidant potential. Results: HPLC analysis revealed eight major isoprenylated xanthones whose concentrations increased with an increasing alcohol percentage. α-Mangostin and γ-mangostin, two major xanthones present in the tinctures, were stable for 12 weeks at room and elevated (40 °C) temperatures, indicating stability of the tincture. In vitro luciferase reporter assays using HepG2-ARE revealed an alcohol concentration-dependent activation of Nrf2 by pericarp and leaf tinctures. The tinctures inhibited lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and reactive oxygen species (ROS) in RAW264.7 cells. Garcinone C (GarC) and garcinone D (GarD) caused significant inhibition of LPS-induced NO production and iNOS expression. GarC and GarD also induced nuclear translocation of Nrf2 and upregulated heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and glutathione S-transferase Pi 1 (GSTP1) in RAW264.7 cells. Conclusions: Taken together, mangosteen tinctures are a significant source of prenylated xanthones with anti-inflammatory and antioxidant potential.

The purple mangosteen fruit (Garcinia mangostana), native to Southeast Asia, has long been used in traditional medicine, however recent data has shown that xanthones, a class of chemical compounds isolated from the mangosteen, display anti-cancer activity [1]. α-Mangostin is the most abundant xanthone with more than 80 that have been isolated and identified from the fruit, roots, bark, and leaves of the mangosteen. Androgen receptor (AR) degradation is a novel strategy that would help to overcome the rising drug resistance to FDA approved anti-androgens that are used to treat prostate cancer [2]. Our data suggests that α-mangostin interacts with the androgen receptor, and may disrupt AR functionality and degrade AR. Two different prostate cancer cell lines (22Rν1 and LNCaP) were used to evaluate efficacy and perform mechanism of action studies. Xanthone treatments promote a dose and time dependent decrease in AR, along with an additional increase in chaperone proteins involved in degradation. Additionally, there is a reduction in the phosphorylation profile of AR, suggesting these actions inhibit the nuclear translocation of AR. Consequently, these actions inhibit the transcription of downstream genes that are necessary for cell growth and proliferation. Our results suggest that α-mangostin promotes AR degradation by inhibiting nuclear translocation and may be effective against drug resistant prostate cancer cases.