A new furanoxanthone from Garcinia mangostana

Garcinone E Mitigates Oxidative Inflammatory Response and Protects against Experimental Autoimmune Hepatitis via Modulation of Nrf2/HO-1, NF-κB and TNF-α/JNK Axis

Garcinia mangostana L. (Clusiaceae), a popular tropical fruit for its juiciness and sweetness, is an opulent fountain of prenylated and oxygenated xanthones with a vast array of bio-activities. Garcinone E (GE), a xanthone derivative reported from G. mangostana, possesses cytotoxic and aromatase inhibitory activities. The present research endeavors to investigate the hepato-protection efficaciousness of GE on concanavalin-A (Con-A)-instigated hepatitis. Results showed that GE pretreating noticeably diminishes both the serum indices (transaminases, ALP, LDH, and γ-GT) and histopathological lesions of the liver. It counteracted neutrophil and CD4+ infiltration into the liver. GE furthered the Nrf2 genetic expression and its antioxidants' cascade, which resulted in amelioration of Con-A-caused oxidative stress (OS), lipid per-oxidative markers (4-HNE, MDA, PC) reduction, and intensified antioxidants (TAC, SOD, GSH) in the hepatic tissue. Additionally, GE prohibited NF-ĸB (nuclear factor kappa-B) activation and lessened the genetics and levels of downstream cytokines (IL1β and IL6). Moreover, the TNF-α/JNK axis was repressed in GE-treated mice, which was accompanied by attenuation of Con-A-induced apoptosis. These findings demonstrated the protective potential of GE in Con-A-induced hepatitis which may be associated with Nrf2/HO-1 signaling activation and OS suppression, as well as modulation of the NF-κB and TNF-α/JNK/apoptosis signaling pathway. These results suggest the potential use of GE as a novel hepato-protective agent against autoimmune hepatitis.

Cytotoxic activity of phytochemicals from Garcinia mangostana L. and G. benthamiana (Planch. & Triana) Pipoly against breast cancer cells

Four xanthones, α-mangostin (1), β-mangostin (2), mangostenol (3), mangaxanthone B (4), three benzophenones, mangaphenone (5), benthamianone (6), congestiflorone (7) and one sterol, stigmasterol (8) were isolated from the stem barks of Garcinia mangostana L. and G. benthamiana (Planch. & Triana) Pipoly. Compounds 1, 2, 4 and 5 exhibited significant cytotoxicity through MTT assay towards MCF-7 and MDA-MB-231 cells with the IC₅₀ values range from 4.4 to 12.0 µM. Remarkably, mangaphenone (5) showed non-cytotoxicity against normal Vero cells, revealing its potential as lead compound for anti-breast cancer drug. Structure-activity relationship postulated that the prenyl and hydroxyl groups present in xanthones are important in promoting anti-proliferative effects. Molecular docking simulation study of 1, 2, 4 and 5 with 2OCF and 4PIV implied that the induction of apoptosis for both cancer cells involve ER and FAS signaling pathways. Future study on the lead optimization of 5 is highly recommended.

Xanthones and Cancer: from Natural Sources to Mechanisms of Action

Xanthones are a class of heterocyclic natural products that have been widely studied for their pharmacological potential. In fact, they have been serving as scaffolds for the design of derivatives focusing on drug development. One of the main study targets of xanthones is their anticancer activity. Several compounds belonging to this class have already demonstrated cytotoxic and antitumor effects, making it a promising group for further exploration. This review therefore focuses on recently published studies, emphasizing their natural and synthetic sources and describing the main mechanisms of action responsible for the anticancer effect of promising xanthones.

The Notch inhibitor cowanin accelerates nicastrin degradation

Aberrant activation of Notch signaling contributes to the pathogenesis of several different types of cancer, and Notch pathway inhibitors may have significant therapeutic potential. Using a unique cell-based assay system, we isolated twelve compounds, including one new natural product from Garcinia speciosa, that inhibit the Notch signaling pathway. HES1 and HES5 are target genes of the Notch cascade, and compound 2, referred to as cowanin, decreased the protein levels of HES1 and HES5 in assay cells. Furthermore, cowanin (2) showed potent cytotoxicity against human leukemic HPB-ALL cells. The Notch signaling inhibitory activity of cowanin (2) is linked to the increased degradation of nicastrin, which is one of the components of the γ-secretase complex. To the best of our knowledge, this is the first example of a compound with Notch pathway inhibitory activity mediated by nicastrin degradation.

Xanthones from the Pericarp of Garcinia mangostana

Mangosteen (Garcinia mangostana L.) is one of the most popular tropical fruits (called the "Queen of Fruits"), and is a rich source of oxygenated and prenylated xanthone derivatives. In the present work, phytochemical investigation has resulted in one new prenylated xanthone and 13 known xanthones isolated from the pericarp of G. mangostana. Their structures were established by spectroscopic data analysis, including X-ray diffraction. The new one was further tested for cytotoxic activity against seven cancer cell lines (CNE-1, CNE-2, A549, H490, PC-3, SGC-7901, U87), displaying the half maximal inhibitory concentration (IC₅0) values 3.35, 4.01, 4.84, 7.84, 6.21, 8.09, and 6.39 μM, respectively. It is noteworthy that the new compound can promote CNE-2 cells apoptosis in late stage, having a remarkable inhibition effect on the side population growth of CNE-2 at 1.26 μM. The bioactive compound was also detected in extract from fresh mangosteen flesh, which indicated that the popular fruit could have potential cytotoxic activity for cancer cell lines.