Two New Prenylated Xanthones from the Pericarp of Garcinia mangostana (Mangosteen)

Two new prenylated xanthones (=9H‐xanthen‐9‐ones), garcimangosxanthones D ( 1 ) and E ( 2 ), together with the six known xanthones 3 – 8 , were isolated from the pericarp of Garcinia mangostana. Their structures were determined by analysis of their spectroscopic data. All of the isolated compounds were biologically evaluated for their in vitro cytotoxic activity against A549, Hep‐G2, and MCF‐7 human‐cancer cell lines and antioxidant activity. Compound 1 exhibited moderate cytotoxicity against Hep‐G2 (IC₅₀=19.2 μM ) and weak cytotoxicity against MCF‐7 (IC₅₀=62.8 μM ) cell lines, and compound 2 showed moderate cytotoxicity against A549, Hep‐G2, and MCF‐7 cell lines with IC₅₀ values of 12.5–20.0 μM (Table 2). Both compounds 1 and 2 demonstrated a weak antioxidant activity with ferric reducing antioxidant power (FRAP) values of 41±7 and 130±4 μmol/g, respectively (Table 3).     

Antifibrotic constituents from Garcinia mangostana

From the CHCl3-soluble fraction of the fruits of Garcinia mangostana (Clusiaceae), six xanthone derivatives, alpha-mangostin (1), gamma-mangostin (2), gartanin (3), deoxygartanin (4), 1-isomangstanin (5) and garcinone E (6), were isolated. All these compounds significantly inhibited HSC-T6 viability as assessed by employing HSC-T6 hepatic stellate cells as an in vitro assay system. Among them, compounds 1 and 2, the most potent and major constituents of G. mangostana, inhibited HSC-T6 viability in dose- and time-dependent manners. In addition, compounds 1 and 2 significantly reduced collagen content, a pathological characteristic of liver fibrosis. Taken together, G. mangostana and its constituents might be beneficial for the treatment of liver fibrosis.     

Xanthones and other constituents of Allanblackia monticola (Guttiferae)

A xanthone derivative, 3,6,7-trihydroxy-1-methoxyxanthone has been isolated from the stem bark of Allanblackia monticola together with other known compounds, 2,6-dihydroxy-1-methoxyxanthone, allanxanthone A, epicathechin and oleanolic acid acetate. The structure of the new compound was elucidated by spectroscopic methods.     

Novel cytotoxic, polyprenylated heptacyclic xanthonoids from Indonesian Garcinia gaudichaudii (Guttiferae)

[reaction: see text] The structures of novel gaudichaudiic acids F-I (1-4), isolated from the bark of Indonesian Garcinia gaudichaudii, have been elucidated by detailed spectral analysis. Gaudichaudiic acid I (4) is probably derived from 1 as a result of allylic oxidation at C-24 and C-21, followed by aromatization.     

Novel Prenylated Xanthones from Garcinia gerrardii HARVEY

Three novel prenylated xanthones, 1–3 , have been isolated from the root bark of Garcinia gerrardii HARVEY ex T. R. SIM (G. natalensis SCHLECHTER ; G. transvaalensis BURTT DAVY ; Guttiferae). Structure elucidation was achieved by a combination of one- and two-dimensional NMR spectroscopic techniques, including long-range HETCOR, mass spectroscopy, and chemical methods. Garcigerrin A ( 1 ) and B ( 2 ) are pyrano derivatives of 3 . They all show a rare 1,4,5 oxygenation pattern of the xanthone nucleus. Xanthone 3 is fungicidal against Cladosporium cucumerinum.     

Xanthones from the bark of Garcinia Xanthochymus

Two novel xanthones, 1,6-dihydroxy-4,5-dimethoxyxanthone (1) and 1,5,6-trihydroxy-7,8-di(3-methyl-2-butenyl)-60,60- dimethylpyrano(20,30:3,4)xanthone (2) were isolated from the bark of Garcinia xanthochymus by normal phase and reverse phase silica gel column chromatography. Their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques.     

Structural Characterization, Biological Effects, and Synthetic Studies on Xanthones from Mangosteen (Garcinia mangostana), a Popular Botanical Dietary Supplement

Mangosteen (Garcinia mangostana L., Clusiaceae) is a popular botanical dietary supplement in the United States, where it is used principally as an antioxidant. It is referred to as the "queen of fruits" in Thailand, a country of origin. The major secondary metabolites of mangosteen, the xanthones, exhibit a variety of biological activities including antibacterial, antifungal, antiinflammatory, antioxidant, antiplasmodial, cytotoxic, and potential cancer chemopreventive activities. Moreover, some of the xanthones from mangosteen have been found to influence specific enzyme activities, such as aromatase, HIV-1 protease, inhibitor κB kinase, quinone reductase, sphingomyelinase, topoisomerase and several protein kinases, and they also modulate histamine H(1) and 5-hydroxytryptamine(2A) receptor binding. Several synthetic procedures for active xanthones and their analogs have been conducted to obtain a better insight into structure-activity relationships for this compound class. This short review deals with progress made in the structural characterization of the chemical constituents of mangosteen, as well as the biological activity of pure constituents of this species and synthetic methods for the mangosteen xanthones.     

Prenylated Xanthone Composition of Garcinia mangostana (Mangosteen) Fruit Hull

Fourteen prenylated xanthones found in mangosteen fruit, Garcinia mangostana L., have been simultaneously separated by reversed-phase high-performance liquid chromatography with water–acetonitrile gradient elution and diode-array detection. The separated xanthones were detected at 254 nm. This new method was developed to establish a chemical fingerprint of the major constituents of mangosteen. It was also used for quantitative analysis of the two major xanthones in crude extracts of mangosteen fruit hull. This chemical fingerprint of G. mangostana extract can be used for comprehensive quality-control of mangosteen extract.     

Xanthones from the green branch of Garcinia dulcis

Two new prenylated xanthones, namely dulcisxanthone H and dulcisxanthone I along with garciniaxanthone C, were isolated from the dichloromethane extract of the green branch of Garcinia dulcis. Their structures were elucidated by the analysis of 1-D and 2-D NMR spectral data. Their antibacterial activities were also examined.     

A Review of the Influence of Various Extraction Techniques and the Biological Effects of the Xanthones from Mangosteen (Garcinia mangostana L.) Pericarps

Xanthones are significant bioactive compounds and secondary metabolites in mangosteen pericarps. A xanthone is a phenolic compound and versatile scaffold that consists of a tricyclic xanthene-9-one structure. A xanthone may exist in glycosides, aglycones, monomers or polymers. It is well known that xanthones possess a multitude of beneficial properties, including antioxidant activity, anti-inflammatory activity, and antimicrobial properties. Additionally, xanthones can be used as raw material and/or an ingredient in many food, pharmaceutical, and cosmetic applications. Although xanthones can be used in various therapeutic and functional applications, their properties and stability are determined by their extraction procedures. Extracting high-quality xanthones from mangosteen with effective therapeutic effects could be challenging if the extraction method is insufficient. Although several extraction processes are in use today, their efficiency has not yet been rigorously evaluated. Therefore, selecting an appropriate extraction procedure is imperative to recover substantial yields of xanthones with enhanced functionality from mangosteens. Hence, the present review will assist in establishing a precise scenario for finding the most appropriate extraction method for xanthones from mangosteen pericarp by critically analyzing various conventional and unconventional extraction methods and their ability to preserve the stability and biological effects of xanthones.     

Two new xanthones from the pericarp of Garcinia mangostana

Two new xanthones, designated garcimangosxanthone F (1) and garcimangosxanthone G (2), were isolated from the EtOAc-soluble fraction of ethanolic extract from the pericarp of Garcinia mangostana. Their structures were established as 1,6,7-trihydroxy-5-(3-methylbut-2-enyl)-8-(3-hydroxy-3-methylbutyl)-6′,6′-dimethylpyrano[2′,3′:3,2]xanthone and 1,6,7-trihydroxy-5-(3-methylbut-2-enyl)-8-(3-hydroxy-3-methylbutyl)-6′,6′-dimethyl-4′,5′-dihydropyrano[2′,3′:3,2]xanthone, respectively, on the basis of their 1D, 2D NMR and MS data interpretation.     

Two new xanthones from the pericarp of Garcinia mangostana

Two new xanthones, 3-hydroxy-6-methoxy-5'-isopropyl-4',5'-dihydrofuro[2',3'?:?7, 8]-6″,6″-dimethyl-4″,5″-dihydropyrano[2″,3″?:?1,2]xanthone (1) and 1,6-dihydroxy-7-methoxy-8-(3-methylbut-3-enyl)-6',6'-dimethyl-4',5'-dihydropyrano[2'3'?:?3,2]xanthone (2), were isolated from the pericarp of Garcinia mangostana. Their structures were elucidated by spectral means (1-D and 2-D NMR, MS).     

Two Unusual Xanthones from the Bark of Garcinia xanthochymus

A new xanthone derivative, garcinexanthone F ( 1 ), which was found to possess an α,β‐unsaturated γ‐lactone moiety, and a new bisxanthone, bigarcinenone B ( 2 ), with a terpene bridge providing the xanthone? xanthone linkage, were isolated from the bark of Garcinia xanthochymus. Their structures were elucidated by spectroscopic methods, especially 2D‐NMR techniques. The antioxidant assay in vitro showed that compounds 1 and 2 exhibited significant scavenging activities against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical with IC₅₀ values of 22.32 and 20.14 μM , and against HO^. radical with IC₅₀ values of 1.16 and 2.85 μM , respectively.     

Epunctanone,a New Benzophenone,and Further Secondary Metabolites from Garcinia epunctata Stapf (Guttiferae)

A new polyprenylated benzophenone, named epunctanone ( 1 ), was isolated from the stem bark of Garcinia epunctata Stapf , together with eight known compounds, 7‐epiisogarcinol ( 2 ), 2,6‐dimethoxy‐p‐benzoquinone ( 3 ), friedelin ( 4 ), lupeol ( 5 ), 16β‐hydroxylupeol ( 6 ), betulin ( 7 ), stigmasterol ( 8 ), and rheediaxanthone A ( 9 ). The structure of epunctanone ( 1 ) was established by detailed analysis of its spectroscopic data, especially 1D‐ and 2D‐NMR, and HR‐MS data. All these compounds were evaluated for their antimicrobial and anti‐protozoan activities. They were also assayed to determine if any of the compounds were nonpeptide agonist ligands for nematodal G‐protein‐coupled receptors, which would be an indication of potential antinematodal activity. Among the isolated compounds, 7‐epiisogarcinol ( 2 ) was the most active against Candida albicans.     

Afzeliixanthones A and B, two new prenylated xanthones from Garcinia afzelii ENGL. (Guttiferae)

Two new prenylated xanthones, afzeliixanthones A (1) and B (2), together with three known xanthones (3-5) and two phytosterols, beta-sitosterol and stigmasterol, were isolated from the CH2Cl2/MeOH (1:1) extract of the stem bark of Garcinia afzelii ENGL. collected in the South West Province of Cameroon. Structures were mainly established using one and two-dimensional NMR and mass spectroscopies. The antioxidant activities of the crude extracts as well as the new compounds (1) and (2) were evaluated.     

Cytotoxic prenylated xanthones from the young fruit of Garcinia mangostana

Three new prenylated xanthones, mangostenones C (1), D (2), and E (3), together with 16 known xanthones 4-19, were isolated from the young fruit (7-week maturity stage) of Garcinia mangostana. The structural elucidation of the new compounds was mainly established on the basis of 1D and 2D NMR and HR-MS spectroscopic analysis. Compound 1 showed cytotoxic properties against three human cancer cell lines, epidermoid carcinoma of the mouth (KB), breast cancer (BC-1), and small cell lung cancer (NCI-H187), with IC50 values of 2.8, 3.53, and 3.72 microg/ml, respectively. Among the isolates, alpha-mangostin (12), the major metabolite, exhibited the most potent effects against the BC-1 cells with an IC50 value of 0.92 microg/ml, an activity greater than that of the standard drug ellipticine (IC50 = 1.46 microg/ml). Compound 12 also showed the highest activity against KB cells, while gartanin (10) displayed the strongest activity against the NCI-H187 cells at the respective IC50 values of 2.08 microg/ml and 1.08 microg/ml.     

Polyprenylated Xanthones and Benzophenones from the Bark of Garcinia oblongifolia

A new polyprenylated xanthone (=9H‐xanthen‐9‐one) and a new polyprenylated benzophenone, namely oblongifolixanthone A ( 1 ) and garciniagifolone A ( 2 ), were isolated from the bark of Garcinia oblongifolia, together with five known compounds including the four xanthones 3 – 5 and 7 and a benzophenone 6 . The structures of 1 and 2 were established by detailed analysis of their spectroscopic data, especially 1D‐ and 2D‐NMR spectra and HR‐ESI‐MS data. All these compounds were assayed for their cytotoxic activities against three human tumor cell lines (HeLa, SGC7901, and HepG2). The 1,3,6,7‐tetrahydroxy‐9H‐xanthen‐9‐one ( 3 ) was inactive, and the other compounds showed weak to moderate activity.     

Antimycobacterial activity of prenylated xanthones from the fruits of Garcinia mangostana

Prenylated xanthones, isolated from the fruit hulls and the edible arils and seeds of Garcinia mangostana, were tested for their antituberculosis potential. Alpha- and beta-mangostins and garcinone B exhibited strong inhibitory effect against Mycobacterium tuberculosis with the minimum inhibitory concentration (MIC) value of 6.25 microg/ml. Tri- and tetra-oxygenated xanthones with di-C5 units or with a C5 and a modified C5 groups are essential for high activities. Substitution in the A and C rings has been shown to modify the bioactivity of the compounds.     

A new antioxidant xanthone from the pericarp of Garcinia mangostana Linn

The air-dried fruit hulls of Garcinia mangostana Linn. were extracted with 85% ethanol. Furthermore, a new xanthone, 1,3,6-trihydroxy-2,5-bis(3-methylbut-2-enyl)-6',6'-dimethyl-4',5'-dihydropyrano[2',3':7,8]xanthone, along with five known xanthones related to their antioxidant activity was purified by silica gel column chromatography and then identified using spectroscopic methods (1D and 2D NMR, MS). The antioxidant activities were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capability. An activity-guided isolation and purification process were used to identify the components, showing the strong DPPH radical-scavenging activity of G. mangostana.     

Multitarget Action of Xanthones from Garcinia mangostana against α-Amylase, α-Glucosidase and Pancreatic Lipase

Digestive enzymes such α-amylase (AA), α-glucosidase (AG) and pancreatic lipase (PL), play an important role in the metabolism of carbohydrates and lipids, being attractive therapeutic targets for the treatment of type 2 diabetes and obesity. Garcinia mangostana is an interesting species because there have been identified xanthones with the potential to inhibit these enzymes. In this study, the multitarget inhibitory potential of xanthones from G. mangostana against AA, AG and PL was assessed. The methodology included the isolation and identification of bioactive xanthones, the synthesis of some derivatives and a molecular docking study. The chemical study allowed the isolation of five xanthones (1–5). Six derivatives (6–11) were synthesized from the major compound, highlighting the proposal of a new solvent-free methodology with microwave irradiation for obtaining aromatic compounds with tetrahydropyran cycle. Compounds with multitarget activity correspond to 2, 4, 5, 6 and 9, highlighting 6 with IC₅₀ values of 33.3 µM on AA, 69.2 µM on AG and 164.4 µM on PL. Enzymatic kinetics and molecular docking studies showed that the bioactive xanthones are mainly competitive inhibitors on AA, mixed inhibitors on AG and non-competitive inhibitors on PL. The molecular coupling study established that the presence of methoxy, hydroxyl and carbonyl groups are important in the activity and interaction of polyfunctional xanthones, highlighting their importance depending on the mode of inhibition.