Garcinoxanthones SV, new xanthone derivatives from the pericarps of Garcinia mangostana together with their cytotoxic and antioxidant activities

In silico studies on the anti-acne potential of Garcinia mangostana xanthones and benzophenones

Garcinia mangostana fruits are used traditionally for inflammatory skin conditions, including acne. In this study, an in silico approach was employed to predict the interactions of G. mangostana xanthones and benzophenones with three proteins involved in the pathogenicity of acne, namely the human JNK1, Cutibacterium acnes KAS III and exo-β-1,4-mannosidase. Molecular docking analysis was performed using Autodock Vina. The highest docking scores and size-independent ligand efficiency values towards JNK1, C. acnes KAS III and exo-β-1,4-mannosidase were obtained for garcinoxanthone T, gentisein/2,4,6,3',5'-pentahydroxybenzophenone and mangostanaxanthone VI, respectively. To the best of our knowledge, this is the first report of the potential of xanthones and benzophenones to interact with C. acnes KAS III. Molecular dynamics simulations using GROMACS indicated that the JNK1-garcinoxanthone T complex had the highest stability of all ligand-protein complexes, with a high number of hydrogen bonds predicted to form between this ligand and its target. Petra/Osiris/Molinspiration (POM) analysis was also conducted to determine pharmacophore sites and predict the molecular properties of ligands influencing ADMET. All ligands, except for mangostanaxanthone VI, showed good membrane permeability. Garcinoxanthone T, gentisein and 2,4,6,3',5'-pentahydroxybenzophenone were identified as the most promising compounds to explore further, including in experimental studies, for their anti-acne potential.

Garcinia macrophylla: a Promising Underutilized Source of Bioactive Compounds in the Amazonia - A Review

Native species from the Amazonia are still unknown or underutilized and few information about their chemical and biological properties are available in the literature. Among the underutilized plant species in the Amazonia, Garcinia macrophylla can be seen as a promising source of bioactive compounds with relevant biological properties. The stem bark and leaves were the main investigated plant parts, mainly concerning the antioxidant, antibacterial, cytotoxicity and antidiabetic properties. However, the bioactive compounds and biological properties of the edible fruits were not yet reported. Systematic investigations covering the Amazonia biome, concerning plants and vegetables as strategic resources are of paramount importance for the sustainable development of the forest. Therefore, this review gathered the available information in the literature concerning general aspects, chemical profile and biological properties of G. macrophylla, for the first time, which highlighted that systematic and robust in vitro and in vivo research, are still needed to elucidate the phytochemical profiles and associated relevant biological properties.

Garcinone C attenuates RANKL-induced osteoclast differentiation and oxidative stress by activating Nrf2/HO-1 and inhibiting the NF-kB signaling pathway

Osteoporosis is the result of osteoclast formation exceeding osteoblast production, and current osteoporosis treatments targeting excessive osteoclast bone resorption have serious adverse effects. There is a need to fully understand the mechanisms of osteoclast-mediated bone resorption, identify new drug targets, and find better drugs to treat osteoporosis. Gar C (Gar C) is a major naturally occurring phytochemical isolated from mangosteen, and is a derivative of the naturally occurring phenolic antioxidant lutein. We used an OP mouse model established by ovariectomy (OVX). We found that treatment with Gar C significantly increased bone mineral density and significantly decreased the expression of TRAP, NFATC1 and CTSK relative to untreated OP mice. We found that Garcinone C could disrupt osteoclast activation and resorption functions by inhibiting RANKL-induced osteoclast differentiation as well as inhibiting the formation of multinucleated osteoclasts. Immunoblotting showed that Gar C downregulated the expression of osteoclast-related proteins. In addition, Gar C significantly inhibited RANKL-induced ROS production and affected NF-κB activity by inhibiting phosphorylation Formylation of P65 and phosphorylation and degradation of ikba. These data suggest that Gar C significantly reduced OVX-induced osteoporosis by inhibiting osteoclastogenesis and oxidative stress in bone tissue. Mechanistically, this effect was associated with inhibition of the ROS-mediated NF-κB pathway.

Biosynthesis and evaluation of a novel highly water-soluble quercetin glycoside derivative

Quercetin (1) was converted into quercetin 7-O-succinyl glucoside (2) by used Bacillus amyloliquefaciens FJ18 as a solvent-resistant whole-cell biocatalyst. The structure of the new compound was confirmed by LC-MS analysis and NMR spectroscopy. The water-solubility of this novel quercetin 7-O-succinyl glucoside (2) was approximately 1000 times higher than that of native quercetin (2). Quercetin (1) and quercetin 7-O-succinyl glucoside (2) exhibited significant DPPH scavenging capacity with IC₅₀ values of 23.55 and 36.05 µM, respectively. Both compounds showed moderate cytotoxic effects against the two human cancer cell lines (MCF-7 and HepG2) with IC₅₀ values ranging from 39.45-63.38 µM.

Antioxidant and antibacterial activities of two xanthones derivatives isolated from the leaves extract of Anthocleista schweinfurthii Gilg (Loganiaceae)

Phytochemical investigations on the dechlorophyllated extract of Anthocleista schweinfurthii Gilg (Loganiaceae) leaves have enabled the isolation of two xanthones derivatives: 1,8-dihydroxy-2,6-dimethoxyxanthone (1) and 1-hydroxy-3,7,8-trimethoxyxanthone (2) known, respectively, as swertiaperenin (1) and decussatin (2), but isolated here for the first time from this plant. The structures of these compounds were investigated by rigorous analysis of their one- and two-dimensional NMR spectral data. Compounds (1) and (2) were evaluated for their antioxidant activities using the 1,1-diphenyl-2-picrylhydrazyl method (DPPH°); the reducing power of iron III (FRAP) and antibacterial activity by the solid diffusion method on three bacteria strains (Escherichia coli, Staphylococcus aureus, and Bacillus cereus). The results obtained show that the two compounds have good antioxidant and antibacterial activities. Obviously, swertiaperenin and decussatin are among the active secondary’s metabolites responsible for the biological activity of A. schweinfurthii Gild recognized by the Cameroonian populations.

Mangostanin, a Xanthone Derived from Garcinia mangostana Fruit, Exerts Protective and Reparative Effects on Oxidative Damage in Human Keratinocytes

The fruit of Garcinia mangostana (mangosteen) is known in ancient traditional Asian medicine for its antioxidant, anti-inflammatory, immunomodulatory and anticancer activities. These effects are mainly due to the action of polyphenols known as xanthones, which are contained in the pericarp of the fruit. In recent years, there has been a growing interest from pharmaceutical companies in formulating new topicals based on mangosteen full extracts to prevent skin aging. However, the molecules responsible for these effects and the mechanisms involved have not been investigated so far. Here, the arils and shells of Garcinia mangostana were extracted with chloroform and methanol, and the extracts were further purified to yield 12 xanthone derivatives. Their effects were evaluated using in vitro cultures of human epidermal keratinocytes. After confirming the absence of cytotoxicity, we evaluated the antioxidant potential of these compounds, identifying mangostanin as capable of both protecting and restoring oxidative damage induced by H₂O₂. We showed how mangostanin, by reducing the generation of intracellular reactive oxygen species (ROS), prevents the activation of AKT (protein kinase B), ERK (extracellular signal-regulated kinase), p53, and other cellular pathways underlying cell damage and apoptosis activation. In conclusion, our study is the first to demonstrate that mangostanin is effective in protecting the skin from the action of free radicals, thus preventing skin aging, confirming a potential toward its development in the nutraceutical and cosmeceutical fields.

Protective Effect of Flavonoids from a Deep-Sea-Derived Arthrinium sp. against ox-LDL-Induced Oxidative Injury through Activating the AKT/Nrf2/HO-1 Pathway in Vascular Endothelial Cells

Oxidized low-density lipoprotein (ox-LDL)-induced oxidative injury in vascular endothelial cells is crucial for the progression of cardiovascular diseases, including atherosclerosis. Several flavonoids have been shown cardiovascular protective effects. Recently, our research group confirmed that the novel flavonoids isolated from the deep-sea-derived fungus Arthrinium sp., 2,3,4,6,8-pentahydroxy-1-methylxanthone (compound 1) and arthone C (compound 2) effectively scavenged ROS in vitro. In this study, we further investigated whether these compounds could protect against ox-LDL-induced oxidative injury in endothelial cells and the underlying mechanisms. Our results showed that compounds 1 and 2 inhibited ox-LDL-induced apoptosis and adhesion factors expression in human umbilical vein vascular endothelial cells (HUVECs). Mechanistic studies showed that these compounds significantly inhibited the ROS level increase and the NF-κB nuclear translocation induced by ox-LDL. Moreover, compounds 1 and 2 activated the Nrf2 to transfer into nuclei and increased the expression of its downstream antioxidant gene HO-1 by inducing the phosphorylation of AKT in HUVECs. Importantly, the AKT inhibitor MK-2206 2HCl or knockdown of Nrf2 by RNA interference attenuated the inhibition effects of these compounds on ox-LDL-induced apoptosis in HUVECs. Meanwhile, knockdown of Nrf2 abolished the effects of the compounds on ox-LDL-induced ROS level increase and the translocation of NF-κB to nuclei. Collectively, the data showed that compounds 1 and 2 protected endothelial cells against ox-LDL-induced oxidative stress through activating the AKT/Nrf2/HO-1 pathway. Our study provides new strategies for the design of lead compounds for related cardiovascular diseases treatment.

Evaluation of the Antioxidant, Antidiabetic, and Antiplasmodial Activities of Xanthones Isolated from Garcinia forbesii and Their In Silico Studies

This study aimed to isolate xanthones from Garcinia forbesii and evaluated their activity in vitro and in silico. The isolated compounds were evaluated for their antioxidant activity by DPPH, ABTS and FRAP methods. The antidiabetic activity was performed against α-glucosidase and α-amylase enzymes. The antiplasmodial activity was evaluated using Plasmodium falciparum strain 3D7 sensitive to chloroquine. Molecular docking analysis on the human lysosomal acid-alpha-glucosidase enzyme (5NN8) and P. falciparum lactate dehydrogenase enzyme (1CET) and prediction of ADMET for the active compound, were also studied. For the first time, lichexanthone (1), subelliptenone H (2), 12b-hydroxy-des-D-garcigerrin A (3), garciniaxanthone B (4) and garcigerin A (5) were isolated from the CH₂Cl₂ extract of the stem bark of G. forbesii. Four xanthones (Compounds 2-5) showed strong antioxidant activity. In vitro α-glucosidase test showed that Compounds 2 and 5 were more active than the others, while Compound 4 was the strongest against α-amylase enzymes. In vitro antiplasmodial evaluation revealed that Compounds 2 and 3 showed inhibitory activity on P. falciparum. Molecular docking studies confirmed in vitro activity. ADMET predictions suggested that Compounds 1-5 were potential candidates for oral drugs. The isolated 2-5 can be used as promising phytotherapy in antidiabetic and antiplasmodial treatment.

Abietane Diterpenoids Isolated from Clerodendrum bracteatum and Their Antioxidant and Cytotoxic Activities

Two new abietane diterpenoids (1,2), along with five known diterpenoids (3–7), were first isolated and purified from the stems of Clerodendrum bracteatum. The structures of the new compounds were established by extensive analysis of mass spectrometric and 1-D, 2-D NMR spectroscopic data. Their antioxidant activities were determined on DPPH radical scavenging and ABTS. The in vitro cytotoxic activities of the compounds were evaluated against the HL-60 and A549 cell lines by the MTT method.