Xanthones from Garcinia smeathmannii (Oliver) and their antimicrobial activity

Antiproliferative activity of a new xanthone derivative from leaves of Garcinia nobilis Engl

A new xanthone, mboudiexanthone (1), together with five known compounds, euxanthone (2), isogarcinol (3), garcinol (4), betulinic acid (5) and zeorin (6) were isolated from the leaves of Garcinia nobilis Engl. The structures were determined by 1D and 2D NMR techniques and X-ray diffraction for 6. The in vitro antiproliferative properties of isolated compounds were evaluated against the human breast cancer cell line MCF-7. All compounds showed an antiproliferative activity with an IC₅₀ value down to ∼11 µM for isogarcinol.

Identification of Xanthones from the Mangosteen Pericarp that Inhibit the Growth of Ralstonia solanacearum

Bacterial wilt caused by Ralstonia solanacearum is one of the most destructive bacterial diseases in agriculture. There is no effective control method, although chemical pesticides are used to prevent this disease, but they may lead to serious problems of environmental pollution. Natural products from plants can be rich and environmentally friendly sources for a broad spectrum biological control of bacteria. This study focuses on the pericarp of mangosteen (Garcinia mangostana) using bioactivity-guided analysis of different fractions and liquid chromatography-mass spectrometry combined with multivariate analysis to determine markers of active fractions. Six prenyl xanthones, including two new xanthones, garcimangosxanthones H and I, were isolated and identified by NMR and HRESIMS. The biomarker γ-mangostin displayed significant activity against the phytopathogen R. solanacearum with an IC₅₀ of 34.7 ± 1.5 μg/mL; γ-mangostin affected the bacterial morphology at a concentration of 16.0 μg/mL as seen with a scanning electron microscope image, and it significantly repressed the virulence-associated genes HrpB, FihD, and PilT of R. solanacearum. γ-Mangostin also reduced the symptoms of bacterial wilt disease effectively that is caused by R. solanacearum in tomato and tobacco seedlings in vitro. These results suggested that the use of γ-mangostin from the mangosteen pericarp against R. solanacearum may be used as a natural bacteriostatic agent in agriculture.

Polyanxanthone, a Xanthone from the Stem Bark of Garcinia Polyantha

A new xanthone polyanxanthone, together with five known xanthones, a pentacyclic triterpene and a benzophenone were isolated from the stem bark of Garcinia polyantha.

Chiral Derivatives of Xanthones with Antimicrobial Activity

According to the World Health Organization, the exacerbated use of antibiotics worldwide is increasing multi-resistant infections, especially in the last decade. Xanthones are a class of compounds receiving great interest in drug discovery and development that can be found as natural products or obtained by synthesis. Many derivatives of xanthones are chiral and associated with relevant biological activities, including antimicrobial. The aim of this review is to compile information about chiral derivatives of xanthones from natural sources and their synthesized examples with antimicrobial activity.

Structures, Activities and Drug-Likeness of Anti-Infective Xanthone Derivatives Isolated from the Marine Environment: A Review

Marine organisms represent almost half of total biodiversity and are a very important source of new bioactive substances. Within the varied biological activities found in marine products, their antimicrobial activity is one of the most relevant. Infectious diseases are responsible for high levels of morbidity and mortality and many antimicrobials lose their effectiveness with time due to the development of resistance. These facts justify the high importance of finding new, effective and safe anti-infective agents. Among the variety of biological activities of marine xanthone derivatives, one that must be highlighted is their anti-infective properties. In this work, a literature review of marine xanthones with anti-infective activity, namely antibacterial, antifungal, antiparasitic and antiviral, is presented. Their structures, biological activity, sources and the methods used for bioactivity evaluation are described. The xanthone derivatives are grouped in three sets: xanthones, hydroxanthones and glycosylated derivatives. Moreover, molecular descriptors, biophysico-chemical properties, and pharmacokinetic parameters were calculated, and the chemical space occupied by marine xanthone derivatives is recognized. The chemical space was compared with marketed drugs and framed accordingly to the drug-likeness concept in order to profile the pharmacokinetic of anti-infective marine xanthone derivatives.

Controllable encapsulation of α-mangostin with quaternized β-cyclodextrin grafted chitosan using high shear mixing

In this study, the inclusion complex formation between α-mangostin and water-soluble quaternized β-CD grafted-chitosan (QCD-g-CS) was investigated. Inclusion complex formation with encapsulation efficiency (%EE) of 5, 15 and 75% can be varied using high speed homogenizer. Tuning %EE plays a role on physicochemical and biological properties of α-mangostin/QCD-g-CS complex. Molecular dynamics simulations indicate that α-mangostin is included within the hydrophobic β-CD cavity and being absorbed on the QCD-g-CS surface, with these results being confirmed by Fourier transform infrared (FTIR) spectroscopy. Probing the release characteristics of the inclusion complex at various %EE (5%, 15% and 75%) in simulated saliva (pH 6.8) demonstrated that α-mangostin release rates were dependent on % EE (order 5% > 15% > 75%). Additionally, higher antimicrobial and anti-inflammation activities were observed for the inclusion complex than those of free α-mangostin due to enhance the solubility of α-mangostin through the inclusion complex with QCD-g-CS.

In vitro antiproliferative activity of uncommon xanthones from branches of Garcinia achachairu

Context Garcinia achachairu Rusby (Clusiaceae) popularly known as 'achachairu' is used in folk medicine to treat rheumatism, inflammation, pain and gastric disorder. Objective The present study investigated the chemical profile and antiproliferative effects of the methanolic extract, fractions and two xanthones, against some carcinoma cell lines in vitro. Materials and methods The compounds were isolated and identified by chromatographic and spectroscopic methods. The extract, fractions and compounds were tested human tumour cell lines of U-251 (glioma), MCF-7 (breast), NCI/ADR-RES (ovary expressing multi-drug resistance phenotype), 786-0 (kidney), NCI-H460 (lung, non-small cells), PC-3 (prostate) and HT-29 (colon), non-tumour cell line HaCat (human keratinocytes) in doses of 0.25-250 μg mL (-) (1) for 48 h. The antiproliferative activity was determined by spectrophotometric quantification (at 540 nm) of the cellular protein content using sulphorhodamine B assay. The prediction of parameters involved in the molecular bioavailability was executed directly by ChemDoodle (version 5.0.1) software (iChemLabs, LLC, Somerset, NJ). Results 3-Demethyl-2-geranyl-4-prenylbellidypholine (1) and 1,5,8-trihydroxy-4',5'-dimethyl-2H-pyrane (2,3:3,2)-4-(3-methylbut-2-enyl) xanthone (2), gartanin (3) and stigmasterol (4) were identified on the basis of spectroscopic techniques. Compounds 1 and 2 exhibited cytocidal activity, especially against breast, prostate and kidney cell lines, with TGI values of 15.8, 4.9, 9.1 and 39.4, 44.7, 40.9 μg/mL, respectively. Discussion and conclusion The presence of two sets of hydrophobic and hydrophilic groups in separate domains in each molecule might play a role in the mediation of tumour-specific action. Our data show that G. achachairu have potent antiproliferative action and should be considered an important source of potent anticancer compounds.

The evaluation of novel natural products as inhibitors of human glutathione transferase P1-1

Glutathione transferase P1-1 is over expressed in some cancer cells and contributes to detoxification of anticancer drugs, leading to drug-resistant tumors. The inhibition of human recombinant GSTP1-1 by natural plant products was investigated using 10 compounds isolated from plants indigenous to Southern and Central Africa. Monochlorobimane and 1-chloro-2,4-dinitrobenzene were used to determine GST activity. Each test compound was screened at 33 and 100 µM. Isofuranonapthoquinone (1) (from Bulbine frutescens) showed 68% inhibition at 33 µM, and sesquiterpene lactone (2) (from Dicoma anomala) showed 75% inhibition at 33 μM. The IC(50) value of 1 was 6.8 μM. The mode of inhibition was mixed, partial (G site) and noncompetitive (H site) with K(i) values of 8.8 and 0.21 µM, respectively. Sesquiterpene 2 did not inhibit the CDNB reaction. Therefore, isofuranonapthoquinone 1 needs further investigations in vivo because of its potent inhibition of GSTP1-1 in vitro.

Antimalarial compounds from the root bark of Garcinia polyantha Olv

Eight compounds were isolated from the roots of Garcinia polyantha, and identified. Two of them, the xanthone garciniaxanthone I (1), and the triterpene, named garcinane (2), are reported as new natural products. The structures of the new compounds were elucidated on the basis of 1D and 2D NMR spectroscopic studies. The structure of compound 1 was confirmed by X-ray crystallography. Among the remaining six known compounds, three were known xanthones [smeathxanthone A (3), smeathxanthone B (4), and chefouxanthone (5)], one benzophenone [isoxanthochymol (6)], one triterpene [magnificol], and one sterol [beta-sitosterol]. The in vitro antimalarial activity of isoxanthochymol (6) against Plasmodium falciparum shows strong chemosuppression of parasitic growth.

Structure elucidation and NMR spectral assignment of five new xanthones from the bark of Garcinia xanthochymus

Five new xanthones, namely Garcinexanthones A-E (1-5), were isolated from the barks of Garcinia xanthochymus. Their structures were elucidated by spectral analysis, primarily NMR, MS, and UV. The complete assignments of the (1)H NMR and (13)C NMR chemical shifts for the compounds were achieved by using 1D and 2D NMR techniques, including DEPT, HSQC, and HMBC NMR experiments.

Medicinal properties of mangosteen (Garcinia mangostana)

Many tropical plants have interesting biological activities with potential therapeutic applications. Garcinia mangostana Linn. (GML) belongs to the family of Guttiferae and is named "the queen of fruits". It is cultivated in the tropical rainforest of some Southeast Asian nations like Indonesia, Malaysia, Sri Lanka, Philippines, and Thailand. People in these countries have used the pericarp (peel, rind, hull or ripe) of GML as a traditional medicine for the treatment of abdominal pain, diarrhea, dysentery, infected wound, suppuration, and chronic ulcer. Experimental studies have demonstrated that extracts of GML have antioxidant, antitumoral, antiallergic, anti-inflammatory, antibacterial, and antiviral activities. The pericarp of GML is a source of xanthones and other bioactive substances. Prenylated xanthones isolated from GML have been extensively studied; some members of these compounds possess antioxidant, antitumoral, antiallergic, anti-inflammatory, antibacterial, antifungal and antiviral properties. Xanthones have been isolated from pericarp, whole fruit, heartwood, and leaves. The most studied xanthones are alpha-, beta-, and gamma-mangostins, garcinone E, 8-deoxygartanin, and gartanin. The aim of this review is to summarize findings of beneficial properties of GML's extracts and xanthones isolated from this plant so far.

Polyanxanthone A, B and C, three xanthones from the wood trunk of Garcinia polyantha Oliv

Three xanthones, polyanxanthone A (1), B (2) and C (3) have been isolated from the methanol extract of the wood trunk of Garcinia polyantha, along with five known xanthones: 1,3,5-trihydroxyxanthone (4); 1,5-dihydroxyxanthone (5); 1,3,6,7-tetrahydroxyxanthone (6); 1,6-dihydroxy-5-methoxyxanthone (7) and 1,3,5,6-tetrahydroxyxanthone (8). Their structures were determined by means of 1D- and 2D-NMR techniques. Some of the above compounds were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes.

Guttiferic acid, a novel rearrangement product from minor chromenoxanthone pigments of Garcinia morella Desr

Morellic and isomorellic acids (2 and 3), present in the seed coat as well as resinous exudate of Garcinia morella Desr., are geometric isomers and structurally related to morellin (1), the major chromenoxanthone pigment. Both form crystalline complexes with pyridine and afford guttiferic acid (7), a novel skeletal rearrangement product, when heated with mild alkali. Structure of the latter has been deduced mainly by a comparative study of 1H and 13C NMR spectra of methyl morellate (5), methyl-O-methyl morellate (6), guttiferic acid (7) and dimethyl guttiferate (8).

Antimicrobial activity of the methanolic extracts and compounds from Vismia laurentii De Wild (Guttiferae)

Methanolic extracts prepared from the leaves, twigs and the roots of Vismia laurentii De Wild as well as nine compounds isolated from these crude extracts, were tested for their antimicrobial activity against Gram-positive bacteria (six species), Gram-negative bacteria (12 species) and two Candida species using disc diffusion and well micro-dilution methods. The disc diffusion assay indicated that the crude extract was active against all the pathogens tested, whereas isolated compounds showed selective activities. The degree of sensitivity of the test organisms to purified compounds varied from 25 to 90%. Fridelin (8) was found to be the most active compound, while Bivismiaquinone (3) was the least active. The lowest minimum inhibition concentration (MIC) values as obtained by the micro-dilution assays were 19.53 and 1.22 microg/ml for the crude extracts and purified compounds, respectively. The lowest value for the purified compounds (1.22 microg/ml) was obtained with O(1)-demethyl-3',4'-deoxypsorospermin-3',4'-diol (6) on Candida gabrata and Bacillus subtilis; 1,8-dihydroxy-6-methoxy-3-methylanthraquinone (5) on Bacillus subtilis and 6-deoxyisojacareubin (7) on Bacillus stearothermophilus. These results provide promising baseline information for the potential use of these crude extracts as well as some of the isolated compounds in the treatment of bacterial and fungal infections.

Antioxidant xanthones from the pericarp of Garcinia mangostana (Mangosteen)

As part of ongoing research on cancer chemopreventive agents from botanical dietary supplements, Garcinia mangostana L. (commonly known as mangosteen) was selected for detailed study. Repeated chromatography of a CH2Cl2-soluble extract of the pericarp led to the isolation of two new highly oxygenated prenylated xanthones, 8-hydroxycudraxanthone G (1) and mangostingone [7-methoxy-2-(3-methyl-2-butenyl)-8-(3-methyl-2-oxo-3-butenyl)-1,3,6-trihydroxyxanthone, 2], together with 12 known xanthones, cudraxanthone G (3), 8-deoxygartanin (4), garcimangosone B (5), garcinone D (6), garcinone E (7), gartanin (8), 1-isomangostin (9), alpha-mangostin (10), gamma-mangostin (11), mangostinone (12), smeathxanthone A (13), and tovophyllin A (14). The structures of compounds 1 and 2 were elucidated by spectroscopic data analysis. Except for compound 2, which was isolated as a minor component, the antioxidant activities of all isolates were determined using authentic and morpholinosydnonimine-derived peroxynitrite methods, and compounds 1, 8, 10, 11, and 13 were the most active. Alpha-mangostin (10) inhibited 7,12-dimethylbenz[alpha]anthracene-induced preneoplastic lesions in a mouse mammary organ culture assay with an IC50 of 1.0 microg/mL (2.44 microM).