γ-Mangostin from Garcinia Mangostana Pericarps as a Dual Agonist That Activates Both PPARα and PPARδ

Cryptoic acids A and B, benzene-containing polyketides, and cyclocryptamide, a modified diketopiperazine, from an actinomycete of the genus Cryptosporangium

Two new benzene-containing polyketides, cryptoic acids A (1) and B (2), along with a new acylated diketopiperazine designated cyclocryptamide (3), were isolated from the culture extract of Cryptosporangium sp. YDKA-T02. The absolute configuration of amino acid components in 3 was determined by Marfey's method. While 3 was not cytotoxic and inactive against microbial test strains, 1 and 2 showed PPARγ agonistic activity in a reporter gene assay and cytotoxicity against P388 murine leukemia cells.

Pakpahan N, Sitohang AI, Sukarno MA, Yuandani, Harahap Y, Setyowati EP, Park MN, Yusoff SD, Zainalabidin S, Prananda AT, Mahadi MK, Kim B, Harahap U, Syahputra RA. In-depth analysis of lupeol: delving into the diverse pharmacological profile

Lupeol, a naturally occurring lupane-type pentacyclic triterpenoid, is widely distributed in various edible vegetables, fruits, and medicinal plants. Notably, it is found in high concentrations in plants like Tamarindus indica, Allanblackia monticola, and Emblica officinalis, among others. Quantitative studies have highlighted its presence in Elm bark, Olive fruit, Aloe leaf, Ginseng oil, Mango pulp, and Japanese Pear bark. This compound is synthesized from squalene through the mevalonate pathway and can also be synthetically produced in the lab, addressing challenges in natural product synthesis. Over the past four decades, extensive research has demonstrated lupeol's multifaceted pharmacological properties, including anti-inflammatory, antioxidant, anticancer, and antibacterial effects. Despite its significant therapeutic potential, clinical applications of lupeol have been limited by its poor water solubility and bioavailability. Recent advancements have focused on nano-based delivery systems to enhance its bioavailability, and the development of various lupeol derivatives has further amplified its bioactivity. This review provides a comprehensive overview of the latest advancements in understanding the pharmacological benefits of lupeol. It also discusses innovative strategies to improve its bioavailability, thereby enhancing its clinical efficacy. The aim is to consolidate current knowledge and stimulate further research into the therapeutic potential of lupeol and its derivatives.

Formulation optimization of sterilized xanthones-loaded nanoemulgels and evaluation of their wound healing activities

Xanthones (XTs) are bioactive compounds found in mangosteen trees (Garcinia mangostana Linn.). They are used as an active ingredient in various health products. However, there is a lack of data of their application in wound healing. In particular, the topical products of XTs for wound healing; they should be sterilized to minimize the risks of wound infection from contaminated microorganisms. This study thus aimed to optimize the formulation of sterilized XTs-loaded nanoemulgel (XTs-NE-G) and to investigate their wound healing activities. The XTs-NE-Gs were prepared by mixing various gels containing sodium alginate (Alg) and Pluronic F127 (F127) into a XTs-nanoemulsion (NE) concentrate according to the face-centered central composite design. The results showed that the optimized XTs-NE-G was A5-F3 containing 5% w/w Alg and 3% w/w F127. It enhanced the proliferation-, migration rates of skin fibroblasts (HFF-1 cells) with an optimal viscosity. After blending the XTs-NE concentrate and the gel that was previously sterilized by a membrane filtration and an autoclaving technique, respectively, the sterilized A5-F3 was obtained. The sterilized A5-F3 still had effective bioactivities towards the HFF-1 cells. It promoted re-epithelialization, collagen deposition and inflammation suppression in the mice' wounds. It could thus be accepted for further investigation in clinical studies.

Natural PPARs agonists for the treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a general term for a series of liver diseases including simple steatosis, non-alcoholic steatohepatitis, liver fibrosis, which is closely related to metabolic syndrome. The pathogenesis of NAFLD is relatively complex, which has gradually changed from the previous 'two-hit' hypothesis to the current "multiple hits" hypothesis. However, there is currently no approved treatment for NAFLD in clinic, highlighting the urgent need for drug development. Peroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor superfamily, whose different subtypes have been proved to regulate different stages of NAFLD, thus becoming promising drug targets for NAFLD. As important sources of drug development, natural products have been proven to treat NAFLD through multiple pathways and multiple targets. In this paper, we outline the regulatory role of PPARs in NAFLD, and summarize some natural products that target PPARs to ameliorate NAFLD, in order to provide reference for drug development of NAFLD.

Mangosteen xanthone γ-mangostin exerts lowering blood glucose effect with potentiating insulin sensitivity through the mediation of AMPK/PPARγ

Diabetes mellitus (DM) is concomitant with significant morbidity and mortality and its prevalence is accumulative in worldwide. The conventional antidiabetic agents are known to mitigate the symptoms of diabetes; however, they may also cause side and adverse effects. There is an imperative necessity to conduct preclinical and clinical trials for the discovery of alternative therapeutic agents that can overcome the drawbacks of current synthetic antidiabetic drugs. This study aimed to investigate the efficacy of lowering blood glucose and underlined mechanism of γ-mangostin, mangosteen (Garcinia mangostana) xanthones. The results showed γ-Mangostin had a antihyperglycemic ability in short (2 h)- and long-term (28 days) administrations to diet-induced diabetic mice. The long-term administration of γ-mangostin attenuated fasting blood glucose of diabetic mice and exhibited no hepatotoxicity and nephrotoxicity. Moreover, AMPK, PPARγ, α-amylase, and α-glucosidase were found to be the potential targets for simulating binds with γ-mangostin after molecular docking. To validate the docking results, the inhibitory potency of γ-mangostin againstα-amylase/α-glucosidase was higher than Acarbose via enzymatic assay. Interestingly, an allosteric relationship between γ-mangostin and insulin was also found in the glucose uptake of VSMC, FL83B, C2C12, and 3T3-L1 cells. Taken together, the results showed that γ-mangostin exerts anti-hyperglycemic activity through promoting glucose uptake and reducing saccharide digestion by inhibition of α-amylase/α-glucosidase with insulin sensitization, suggesting that γ-mangostin could be a new clue for drug discovery and development to treat diabetes.

Natural Xanthones and Skin Inflammatory Diseases: Multitargeting Mechanisms of Action and Potential Application

The pathogenesis of skin inflammatory diseases such as atopic dermatitis, acne, psoriasis, and skin cancers generally involve the generation of oxidative stress and chronic inflammation. Exposure of the skin to external aggressors such as ultraviolet (UV) radiation and xenobiotics induces the generation of reactive oxygen species (ROS) which subsequently activates immune responses and causes immunological aberrations. Hence, antioxidant and anti-inflammatory agents were considered to be potential compounds to treat skin inflammatory diseases. A prime example of such compounds is xanthone (xanthene-9-one), a class of natural compounds that possess a wide range of biological activities including antioxidant, anti-inflammatory, antimicrobial, cytotoxic, and chemotherapeutic effects. Many studies reported various mechanisms of action by xanthones for the treatment of skin inflammatory diseases. These mechanisms of action commonly involve the modulation of various pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor α (TNF-α), as well as anti-inflammatory cytokines such as IL-10. Other mechanisms of action include the regulation of NF-κB and MAPK signaling pathways, besides immune cell recruitment via modulation of chemokines, activation, and infiltration. Moreover, disease-specific activity contributed by xanthones, such as antibacterial action against Propionibacterium acnes and Staphylococcus epidermidis for acne treatment, and numerous cytotoxic mechanisms involving pro-apoptotic and anti-metastatic effects for skin cancer treatment have been extensively elucidated. Furthermore, xanthones have been reported to modulate pathways responsible for mediating oxidative stress and inflammation such as PPAR, nuclear factor erythroid 2-related factor and prostaglandin cascades. These pathways were also implicated in skin inflammatory diseases. Xanthones including the prenylated α-mangostin (2) and γ-mangostin (3), glucosylated mangiferin (4) and the caged xanthone gambogic acid (8) are potential lead compounds to be further developed into pharmaceutical agents for the treatment of skin inflammatory diseases. Future studies on the structure-activity relationships, molecular mechanisms, and applications of xanthones for the treatment of skin inflammatory diseases are thus highly recommended.

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

A pair of geometrically isomeric unsaturated keto fatty acids, (6E,8Z)- and (6E,8E)-5-oxo-6,8-tetradecadienoic acids (1 and 2), were isolated from the culture broth of an actinomycete of the genus Micrococcus, which was associated with a stony coral, Catalaphyllia sp. Their chemical structures were elucidated by spectroscopic analysis including NMR and MS, with special assistance of spin system simulation studies for the assignment of an E geometry at C8 in 2. As metabolites of microbes, compounds 1 and 2 are unprecedented in terms of bearing a 2,4-dienone system. Both 1 and 2 showed antibacterial activity against the plant pathogen Rhizobium radiobacter and the fish pathogen Tenacibaculum maritimum, with a contrasting preference that 1 is more effective to the former strain while 2 is so to the latter. In addition, compounds 1 and 2 displayed agonistic activity against peroxisome proliferator-activated receptors (PPARs) with an isoform specificity towards PPARα and PPARγ.

γ-Mangostin Ameliorates Free Fatty Acid-Induced Lipid Accumulation via the SIRT1/LKB1/AMPK Pathway in HepG2 and L02 Cells

Lipid accumulation is a typical characteristic of nonalcoholic fatty liver disease (NAFLD). The inhibition of lipid accumulation is regarded as a potential treatment for NAFLD. In this study, we investigated the effects of γ-mangostin or α-mangostin on lipid accumulation in a cell model. Analysis of the inhibitory effects of γ-mangostin on lipid accumulation revealed that it downregulated NAFLD-related biochemical parameters and stimulated the SIRT1/LKB1/AMPK pathway. Consequently, it suppressed lipid synthesis and enhanced fatty acid oxidation. Moreover, we demonstrated that the blockage of AMP-activated protein kinase (AMPK) by the pharmacological inhibitor Compound C abrogated the promoting effect of AMPK. Similar results were also observed for α-mangostin. The effects of α-mangostin on lipid accumulation were inferior to those of γ-mangostin. The differences in CPT1A activity might be originated from their different chemical structures. Our results suggested that γ-mangostin and α-mangostin can be exploited as potential candidates for NAFLD treatment.

Isolation, Identification, and Synthesis of a New Prenylated Cinnamic Acid Derivative from Brazilian Green Propolis and Simultaneous Quantification of Bioactive Components by LC-MS/MS

A new cinnamic acid derivative, (E)-3-[4-hydroxy-3-((E)-3-formyl-2-butenyl)phenyl]-2- propenoic acid (20) has been isolated from the ethanol extract of Brazilian green propolis along with three known cinnamic acid derivatives, 3,4-dihydroxy-5-prenyl-(E)-cinnamic acid (4), capillartemisin A (6), and 2,2-dimethylchromene-6-(E)-propenoic acid (8), and a flavonoid, dihydrokaempferide (16) by liquid-liquid participation, a series of column chromatography and preparative HPLC. Their structures have been determined by spectroscopic analyses and chemical synthesis of compound 20. The simultaneous quantification of 20 constituents, including 10 cinnamic acid derivatives, 7 flavonoids, and 3 caffeoylquinic acid derivatives, has also been developed and validated using LC-MS/MS. The new compound 20 was shown to activate PPAR α but not PPAR β or γ.

Crude α-Mangostin Suppresses the Development of Atherosclerotic Lesions in Apoe-Deficient Mice by a Possible M2 Macrophage-Mediated Mechanism

Lifestyle choices play a significant role in the etiology of atherosclerosis. Male Apoe^−/− mice that develop spontaneous atherosclerotic lesions were fed 0%, 0.3%, and 0.4% mangosteen extracts, composed largely of α-mangostin (MG), for 17 weeks. Body weight gains were significantly decreased in both MG-treated groups compared to the control, but the general condition remained good throughout the study. The levels of total cholesterol (decreased very-low-density lipoprotein in lipoprotein profile) and triglycerides decreased significantly in the MG-treated mice in conjunction with decreased hepatic HMG-CoA synthase and Fatty acid transporter. Additionally, increased serum lipoprotein lipase activity and histopathology further showed a significant reduction in atherosclerotic lesions at both levels of MG exposure. Real-time PCR analysis for macrophage indicators showed a significant elevation in the levels of Cd163, an M2 macrophage marker, in the lesions of mice receiving 0.4% MG. However, the levels of Nos2, associated with M1 macrophages, showed no change. In addition, quantitative immunohistochemical analysis of macrophage subtypes showed a tendency for increased M2 populations (CD68⁺/CD163⁺) in the lesions of mice given 0.4% MG. In further analysis of the cytokine-polarizing macrophage subtypes, the levels of Interleukin13 (Il13), associated with M2 polarization, were significantly elevated in lesions exposed to 0.4% MG. Thus, MG could suppress the development of atherosclerosis in Apoe^−/− mice, possibly through an M2 macrophage-mediated mechanism.

Cellular and Biophysical Pipeline for the Screening of Peroxisome Proliferator-Activated Receptor Beta/Delta Agonists: Avoiding False Positives

Peroxisome proliferator-activated receptor beta/delta (PPARß/δ) is considered a therapeutic target for metabolic disorders, cancer, and cardiovascular diseases. Here, we developed one pipeline for the screening of PPARß/δ agonists, which reduces the cost, time, and false-positive hits. The first step is an optimized 3-day long cellular transactivation assay based on reporter-gene technology, which is supported by automated liquid-handlers. This primary screening is followed by a confirmatory transactivation assay and by two biophysical validation methods (thermal shift assay (TSA) and (ANS) fluorescence quenching), which allow the calculation of the affinity constant, giving more information about the selected hits. All of the assays were validated using well-known commercial agonists providing trustworthy data. Furthermore, to validate and test this pipeline, we screened a natural extract library (560 extracts), and we found one plant extract that might be interesting for PPARß/δ modulation. In conclusion, our results suggested that we developed a cheaper and more robust pipeline that goes beyond the single activation screening, as it also evaluates PPARß/δ tertiary structure stabilization and the ligand affinity constant, selecting only molecules that directly bind to the receptor. Moreover, this approach might improve the effectiveness of the screening for agonists that target PPARß/δ for drug development.

Medicinal properties of mangosteen (Garcinia mangostana L.): A comprehensive update

Garcinia mangostana L. (Clusiaceae) is a tropical tree native to Southeast Asia known as mangosteen which fruits possess a distinctive and pleasant taste that has granted them the epithet of "queen of the fruits". The seeds and pericarps of the fruit have a long history of use in the traditional medicinal practices of the region, and beverages containing mangosteen pulp and pericarps are sold worldwide as nutritional supplements. The main phytochemicals present in the species are isoprenylated xanthones, a class of secondary metabolites with multiple reports of biological effects, such as antioxidant, pro-apoptotic, anti-proliferative, antinociceptive, anti-inflammatory, neuroprotective, hypoglycemic and anti-obesity. The diversity of actions displayed by mangosteen xanthones shows that these compounds target multiple signaling pathways involved in different pathologies, and place them as valuable sources for developing new drugs to treat chronic and degenerative diseases. This review article presents a comprehensive update of the toxicological findings on animal models, and the preclinical anticancer, analgesic, neuroprotective, antidiabetic and hypolipidemic effects of G. mangostana L. extracts and its main isolates. Pharmacokinetics, drug delivery systems and reports on dose-finding human trials are also examined.

Synthetic and natural Peroxisome Proliferator-Activated Receptor (PPAR) agonists as candidates for the therapy of the metabolic syndrome

INTRODUCTION

Peroxisome proliferator-activated receptors (PPARs) are the molecular targets of hypolipidemic and insulin-sensitizing drugs and implicated in a multitude of processes that fine-tune the functions of all organs in vertebrates. As transcription factors they sense endogenous and exogenous lipid signaling molecules and convert these signals into intricate gene responses that impact health and disease. The PPARs act as modulators of cellular, organ, and systemic processes, such as lipid and carbohydrate metabolism, making them valuable for understanding body homeostasis influenced by nutrition and exercise. Areas covered: This review concentrates on synthetic and natural PPAR ligands and how they have helped reveal many aspects of the transcriptional control of complex processes important in health. Expert opinion: The three PPARs have complementary roles in the fine-tuning of most fundamental body functions, especially energy metabolism. Understanding their inter-relatedness using ligands that simultaneously modulate the activity of more than one of these receptors is a major goal. This approach may provide essential knowledge for the development of dual or pan-PPAR agonists or antagonists as potential new health-promoting agents and for nutritional approaches to prevent metabolic diseases.

Multitargeted bioactive ligands for PPARs discovered in the last decade

Type 2 diabetes took insulin resistance as the main clinical manifestation. PPARs have been reported to be the therapeutic targets of metabolic disorders, such as obesity, hypertension, diabetes, and cardiovascular disease. Previously, PPARγ agonist rosiglitazone was restricted in clinic due to cardiomyocytes infarction, weight gain, and other serious side-effects, which were mainly due to the single and selective PPARγ agonism. In recent years, multitarget-directed PPAR agonists with synergistic reaction as well as fewer side-effect have been the hot topic in designing promising agents. In this review, we updated and generalized the development of PPARγ partial agonists, PPARγ antagonists, PPARα/γ dual agonists, PPARδ partial agonists, PPARδ antagonists, PPARα/δ dual agonists, PPARγ/δ dual agonists, and PPARα/γ/δ pan-agonists published in recent decade. Most of these molecules were modified from known structures or came from high-throughput screening. Among these molecules, some were expected to be promising drugs against metabolic disorders, while others seemed to provide new insight for designing novel PPAR agents.