A new xanthone derivative from twigs of Garcinia nobilis

Trihydroxyxanthones from the heartwood of Maclura cochinchinensis modulate M1/M2 macrophage polarisation and enhance surface TLR4

The anti-inflammatory actions of phytochemicals have attracted much attention due to the current state of numerous inflammatory disorders. Thai traditional medicine uses Maclura cochinchinensis (Lour.) Corner to treat chronic fever and various inflammatory diseases, as well as to maintain normal lymphatic function. Five flavonoids and five xanthones were isolated from the heartwood of M. cochinchinensis and we investigated the anti-inflammatory properties of the isolated compounds. All isolated compounds possessed an anti-inflammatory effect by decreasing prostaglandin E₂ (PGE₂) synthesis in lipopolysaccharide (LPS)-activated murine macrophages with varying degrees of potency. The greatest decrease in M1 inflammatory mediators, nitric oxide, PGE₂, and proinflammatory cytokines was observed with 1,3,7-trihydroxyxanthone and 1,3,5-trihydroxyxanthone treatment of LPS-activated macrophages. The anti-inflammatory mechanism of the two xanthones is mediated by the suppression of inducible nitric oxide synthase, cyclooxygenase-2, and phosphatidylinositol 3-kinase/protein kinase B expression and the upregulation of M2 anti-inflammatory signalling proteins phosphorylated signal transducer and activator of transcription 6 and peroxisome proliferator-activated receptors-γ. 1,3,7-Trihydroxyxanthone exhibits superior induction of anti-inflammatory M2 mediator of LPS-activated macrophages by upregulating arginase1 expression. Following the resolution of inflammation, the two xanthones enhanced surface TLR4 expression compared to LPS-stimulated cells, possibly preserving macrophage function. Our research highlights the role of the two xanthones in modulating the M1/M2 macrophage polarisation to reduce inflammation and retain surface TLR4 once inflammation has been resolved. These findings support the use of xanthones for their anti-inflammatory effects in treating inflammatory dysregulation.

Heptacyclosordarianone, a New Polyketide From Sordaria sp., an Endophytic Fungus From Garcinia polyantha

One new polyketide derivative, heptacyclosordarianone (1), together with 2 known compounds, heptacyclosordariolone (2) and sordariol (3), were isolated from an extract of Sordaria sp. AM-71, an endophytic fungus inhabiting Garcinia polyantha. The structures of these compounds were elucidated based on intensive nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry and by comparison with literature data. All compounds were assayed for their antimicrobial and cytotoxic properties. Only compound 2 showed antimicrobial activities against Bacillus subtilis DSMZ 704 , Pseudomonas agarici DSMZ 11810, and Micrococcus luteus DSMZ 1605 with minimum inhibitory concentration values of 9.3, 15.5, and 16.9 µg/mL respectively. None of the isolated compounds showed a significant cytotoxic property.

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.

Cytotoxic xanthones from the roots of Mesua ferrea L

Five undescribed xanthones, 4-methoxypyranojacareubin, 4-hydroxy-3-prenylpyranoxanthone, 1-hydroxy-5,7-dimethoxyxanthone, 5-hydroxy-1,6,7-trimethoxyxanthone and 2-hydroxy-1,5-dimethoxyxanthone, together with thirty-three known xanthones were isolated from the roots of Mesua ferrea L. The structures of all isolated xanthones were elucidated based on spectroscopic methods. 5-Hydroxy-1,6,7-trimethoxyxanthone and 2-hydroxy-1,5-dimethoxyxanthone were also confirmed by X-ray diffraction data. In addition, the isolated compounds were determined for antibacterial, antioxidant and cytotoxic activities. The known 1,5,6-trihydroxyxanthone showed cytotoxicity against A375, PC-3 and HaCaT cell lines with IC₅₀ values of 5.73 μg/mL, 5.93 μg/mL and 8.94 μg/mL, respectively.

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.

Two new xanthone epimers from the processed gamboge

Two new xanthones, gambogollic acid (1), epigambogollic acid (2), together with three rare compounds, gambogellic acid (3), epigambogellic acid (4) and gambogic acid (5), were isolated from the processed gamboge. The new structures were determined by 1D and 2D NMR spectroscopic analysis. And the cytotoxicity of these five compounds was evaluated against human hepatoma carcinoma and human lung adenocarcinoma cell. Two new compounds showed excellent antitumor activity. All five compounds exhibited inhibitory effect against SMMC-7221cell and A549 cell.

LC/MS characterization of phenolic antioxidants of Brindle berry (Garcinia gummi-gutta (L.) Robson)

Characterisation of antioxidant fraction of the fruit of Garcinia gummi-gutta was done using liquid chromatography mass spectroscopic (LC/MS) analyses. Total poly phenolics and radical scavenging activity of various extracts such as acetone, methanol and hydroalcohol were estimated spectrophotometrically. The active extract was analysed by LC/MS in order to identify the molecular mass and tentative structures of major compounds. Phenolic compounds such as luteolin 7-O-glucuronide, kaempferol 3-O-(6-O-acetyl) glycoside, dicaffeoylquinic acid, apigenein-6-C-pentosyl-8-C-hexoside and p-coumarylquinic acid were identified from hydro alcoholic extract of G. gummi-gutta.

Anti-mycobacterial activity of polyketides from Penicillium sp. endophyte isolated from Garcinia nobilis against Mycobacteriumsmegmatis

OBJECTIVE/BACKGROUND

According to estimates by the World Health Organization, there were 9.6 million new tuberculosis (TB) cases in 2014: 5.4 million among men, 3.2 million among women, and 1.0 million among children. There were also 1.5 million TB deaths. Although there are potent anti-TB molecules, the misuse of these drugs in addition to inconsistent or partial treatment have led to the development of multidrug-resistant TB and extensively drug-resistant TB. It is established that plants harbor microorganisms, collectively known as endophytes, which also produce metabolites. Exploring the as-yet untapped natural products from the endophytes increases the chances of finding novel and active compounds. The present study was aimed to investigate the antimycobacterial activity of the crude extract and compounds isolated from Penicillium sp. endophyte associated with Garcinia nobilis against Mycobacterium smegmatis.

METHODS

Liquid culture obtained from the fermentation of Penicillium sp. was extracted using ethylacetate and the liquid chromatography-mass spectrometry monitored fractionation of crude extracts yielded six compounds. Their structures were elucidated with spectroscopic analyses including two-dimensional nuclear magnetic resonance, high resolution mass spectrometry by dereplication using Antibase, and by comparison to literature data. All compounds and the crude extract from the liquid medium were evaluated for their antimycobacterial activity against M. smegmatis.

RESULTS

In this study, the activity of penialidins A-C (1-3), citromycetin (4), p-hydroxy phenyl glyoxalaldoxime (5), and Brefeldin A (6) were tested against nonpathogenic M. smegmatis. Penialidin C was the most active compound with a minimum inhibitory concentration of 15.6μg/mL.

CONCLUSION

Isolated compounds from Penicillium sp. harbored in G. nobilis exhibited promising antimycobacterial activity against M. smegmatis thus supporting the immensity of the potential of antimycobacterial drug discovery from endophytes from medicinal plants. Penialidin C could further be investigated for antimycobacterial drug development.