Prenylated xanthones from the bark of Garcinia xanthochymus and their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities

Anti-rheumatoid arthritis potential of different fractions derived from of Coluria longifolia

Coluria longifolia Maxim (C. longifolia) is a Chinese folk medication commonly used to treat arthritis and joint pain. Literatures have reported that C. longifolia has significant anti-inflammatory, analgesic and antipyretic effects. The aim of this research was to assay the effective fractions of C. longifolia (EFCL) against rheumatoid arthritis (RA) and to elucidate its anti-RA mechanism on a preliminary basis. The rat model of collagen-induced arthritis (CIA) was established. The therapeutic effects of different fractions in vivo were evaluated by body weight changes, a foot swelling score, inflammatory factors and histopathological examination. The mechanism of EFCL was investigated by activity of oxidative stress related enzyme, qPCR and Western blotting tests. In vivo results showed that total extraction (TE) and n-butanol fraction (NF) could significantly alleviate the symptoms of RA, decrease the levels of IL-6 and TNF-α (P < 0.01), and improve histopathological injury. The mechanism study showed that SOD level was significantly increased with MDA level decreased in the NF group. The upregulated proteins and mRNA expression levels of Nrf2, HO1 and NQO1 after TE and NF administration suggested that the anti-arthritic effect may be related to the Nrf2 signaling pathway and downstream HO1 and NQO1. In conclusion, this study confirmed that C. longifolia is capable of treating RA with NF as the main effective fraction. Its anti-RA action may be associated with Nrf2 signaling pathway and downstream HO1 and NQO1.

Garcicowanones C-E, three new hydrated-geranylated xanthones from the roots of Garcinia cowa Roxb. ex Choisy, and their α-glucosidase inhibition activities

Three new xanthones, garcicowanones C-E (1 - 3), and six known xanthones (4 - 9) were isolated from the roots of Garcinia cowa Roxb. ex Choisy. Their chemical structures were determined using spectroscopic technics, including HR-ESI-MS and 2 D NMR. All isolated compounds were evaluated for in vitro α-glucosidase inhibition. Cowanol (6) and norcowanin (8) had the most potent α-glucosidase inhibitory activity, with respective IC50 values of 33.5 ± 0.8 and 17.2 ± 0.3 µM, compared with the positive control, acarbose (IC50 257.3 ± 4.8 µM).

Phytochemical and Functional Characterization of Different Parts of the Garcinia xanthochymus Fruit

The fruit of Garcinia xanthochymus is consumed traditionally and is known to possess health-promoting effects. However, studies involving the characterization of phytochemicals of different parts of the fruit, and their biological activity were limited and hence warranted a comprehensive study. The proximate analyses reveal that fruit peel was rich in crude fiber. The levels of essential minerals, fatty acids, amino acids, carotenoids, organic acids, and polyphenols were significantly higher in the peel, followed by the rind, seed, and pulp. The in vitro antioxidant assays revealed that the polyphenolic extract of the peel possesses a high antioxidant effect compared to the extracts from other parts of theG. xanthochymus fruit. Furthermore, the in vitro assays reveal the antidiabetic potential of the methanol extract. This is the first comprehensive report involving the characterization and biological properties of different parts of the G. xanthochymus fruit. Hence, our study implicates the potential use of this fruit for the development of functional foods for diabetes.

Design of potential probiotic yeast starters tailored for making a cornelian cherry (Cornus mas L.) functional beverage

We carried out a step-by-step accurate procedure to design yeast starters with probiotic and technological traits to ferment cornelian cherry fruits puree (CP). Pichia kudriavzevii DCNa1 and Wickerhamomyces subpelliculosus DFNb6 were selected as binary starters due to their metabolic traits and low ethanol yield. Fermentation by selected starters positively affected the physical stability of CP. Depletion of loganic and cornuside acids during CP fermentation, leads us to speculate that yeasts might be involved in the conversion of iridoids to bioactive derivatives. Compared to unfermented CP, fermentation also affected the profile of CP volatiles, resulting in higher amount of alcohols and esters, and lower levels of aldehydes and alkanes. Viable cell number of selected yeasts in CP after 21 days of storage at 4 °C as well as after in vitro simulated digestion remained above the minimum dose recommended for a probiotic beverage. Under the in vitro gastrointestinal batch simulating the digestion process, we provided original evidence about the ability of yeasts conveyed by fermented CP to modulate the intestinal microbiota. We also faced some issues related to the yeasts physiology and the link between biofilm and cell viability that still deserve to be more in depth investigated.

Garcinia xanthochymus extract protects PC12 cells from H2O2-induced apoptosis through modulation of PI3K/AKT and NRF2/HO-1 pathways

The aim of the present study was to investigate the protective effects and underlying mechanisms of Garcinia xanthochymus, a perennial medicinal plant native to Yunnan, China, against H₂O₂-induced oxidative damage in rat pheochromacytoma PC12 cells. Preincubation of PC12 cells with fruit EtOAc fraction (fruit-EFr., 12.5-50 µmol·L^-1) of G. xanthochymus for 24 h prior to H₂O₂ exposure markedly improved cell viability and increased the activities of antioxidant enzymes (superoxide dismutase, catalase, and heme oxygenase-1 [HO-1]), prevented lactate dehydrogenase release and lipid peroxidation malondialdehyde production, attenuated the decrease of matrix metalloproteinases (MMP), and scavenged reactive oxygen species (ROS). Fruit-EFr. also reduced BAX and cytochrome C expression and improved BCL-2 expression, thereby decreasing the ratio of BAX to BCL-2. Fruit-EFr. activated the nuclear translocation of NRF2 to increase HO-1 and induced the phosphorylation of AKT. Its cytoprotective effect was abolished by LY294002, a specific inhibitor of PI3K. Taken together, the above findings suggested that fruit-EFr.of G. xanthochymus could enhance cellular antioxidant defense capacity, at least in part, through upregulating HO-1 expression and activating the PI3K/AKT pathway and that it could suppress H₂O₂-induced oxidative damage via PI3K/AKT and NRF2/HO-1 signaling pathways.

Chemical and Biological Research on Herbal Medicines Rich in Xanthones

Xanthones, as some of the most active components and widely distributed in various herb medicines, have drawn more and more attention in recent years. So far, 168 species of herbal plants belong to 58 genera, 24 families have been reported to contain xanthones. Among them, Calophyllum, Cratoxylum, Cudrania, Garcinia, Gentiana, Hypericum and Swertia genera are plant resources with great development prospect. This paper summarizes the plant resources, bioactivity and the structure-activity relationships (SARs) of xanthones from references published over the last few decades, which may be useful for new drug research and development on xanthones.

Antibacterial Compounds from the Roots of Cratoxylum formosum spp. pruniflorum

Phytochemical investigation of the roots of Cratoxylum formosum spp. pruniflorum led to the isolation and identification of a new xanthone, namely cratopruniforone (1), together with 13 known compounds (2–14). Some of these more abundant compounds were evaluated for their antibacterial activities.

Rapid screening and identification of α-amylase inhibitors from Garcinia xanthochymus using enzyme-immobilized magnetic nanoparticles coupled with HPLC and MS

α-Amylase inhibitors play an important role in management of diabetes and obesity. In order to rapidly discover potent α-amylase inhibitors from medicinal plants, a ligands-screening method based on enzyme-immobilized magnetic nanoparticles integrated with HPLC was developed. Amine-terminated magnetic nanoparticles were prepared for the immobilization of α-amylase. Based on the affinity theory, the α-amylase-coated magnetic nanoparticles were employed to fish out the ligands from the extracts of Garcinia xanthochymus, and the elutes were examined by HPLC. As a result, three ligands were screened out. Isolation and identification were carried out subsequently. By analyzing the UV, MS and NMR spectra, they were identified as three biflavonoids including GB2a glucoside (2), GB2a (3) and fukugetin (4). The IC50 values of the three compounds were also determined. The results suggest the proposed approach is efficient and accurate, and has great potential in rapid discovery of drug candidates from medical plants.

Xanthones with Antiproliferative Effects on Prostate Cancer Cells from the Stem Bark of Garcinia xanthochymus

Investigations of the constituents of the stem barks of Garcinia xanthochymus have yielded two new compounds, garcinenones X (1) and Y (2), along with five known xanthones, 1,4,5,6-tetrahydroxy-7-(3-methylbut-2-enyl)xanthone (3), 1,4,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (4), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (5), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methylbut-2-enyl)xanthone (6), and 1,5,6-trihydroxy-7,8-di(3-methylbut-2-enyl)-6′,6'dimethylpyrano(2′,3′:3,4)xanthone (7). The structures of the compounds were determined by spectroscopic methods. The cell growth inhibitory activity of the isolated compounds against the PC-3 cell line was measured. Among them, compounds 2, 3, 5, and 6 exhibited significant inhibitory effects with IG50 values of 14.3, 15.5, 11.1, and 6.8 μM, respectively.