Amelioration of Experimental Autoimmune Encephalomyelitis by Isogarcinol Extracted from Garcinia mangostana L. Mangosteen

Synergistic combination of isogarcinol isolated from edible fruits of Garcinia multiflora and dexamethasone to overcome leukemia glucocorticoid resistance

Isogarcinol (ISO), a cytotoxic polycyclic polyprenylated acylphloroglucinol isolated from the edible fruits of Garcinia multiflora. However, synergistic combination of ISO and dexamethasone (DEX) to overcome leukemia glucocorticoid resistance has never been investigated. Therefore, in this study, the effects of ISO in combination with DEX was conducted on leukemia in vivo and glucocorticoid resistance in vitro. As a result, the combination of the two compounds could efficiently inhibit leukemia progression in mice and reverse DEX resistance in acute lymphoblastic leukemia (ALL) Jurkat cells. Significantly, our findings indicated that c-Myc may be a potential target of ISO, as it is involved in cell cycle arrest and apoptosis by the combination of ISO and DEX in Jurkat cells. Furthermore, western blot analysis revealed that ISO and DEX inhibits the PI3K/Akt/mTOR signaling pathway and promotes the nuclear translocation of glucocorticoid receptor (GR), which activates target genes NR3C1 and TSC22D3, leading to apoptosis in Jurkat cells. Hence, our results suggest that ISO, as a safe and effective food-derived agent, can enhance the anti-leukemia effects of DEX.

Role of Network Pharmacology in Prediction of Mechanism of Neuroprotective Compounds

Network pharmacology is an emerging pioneering approach in the drug discovery process, which is used to predict the therapeutic mechanism of compounds using various bioinformatic tools and databases. Emerging studies have indicated the use of network pharmacological approaches in various research fields, particularly in the identification of possible mechanisms of herbal compounds/ayurvedic formulations in the management of various diseases. These techniques could also play an important role in the prediction of the possible mechanisms of neuroprotective compounds. The first part of the chapter includes an introduction on neuroprotective compounds based on literature. Further, network pharmacological approaches are briefly discussed. The use of network pharmacology in the prediction of the neuroprotective mechanism of compounds is discussed in detail with suitable examples. Finally, the chapter concludes with the current challenges and future prospectives.

Glycyrol Prevents the Progression of Psoriasis-like Skin Inflammation via Immunosuppressive and Anti-Inflammatory Actions

Glycyrol (GC) is one natural active product. Imiquimod-induced psoriasis-like Balb/c mouse models were established. The model mice were intraperitoneally injected with cyclosporine A (CsA) and GC for 8 days followed by a series of biological detections. GC had little toxicity according to the levels of peripheral blood cells, hemoglobin, blood urea nitrogen (BUN), and serum creatinine (CRE), while CsA significantly increased the levels of BUN and CRE. GC decreased the splenic index and reduced the expressions of IL-6, IL-23, and CXCL-3 in the model mice and IL-6, CXCL-1, and CXCL-2 in the inflammatory HaCaT cells. The half inhibition concentration (IC50) of GC on HaCaT cells was 29.72 μmol/L, resulting in improved apoptosis, enhanced expressions of p21, BAX, and BIK, and reduced expressions of BCL-2. GC is an immunosuppressive agent against psoriasis-like symptoms by anti-inflammatory effects, which provides a strategy for the discovery of anti-psoriatic natural products.

Garcinia oligantha: A comprehensive overview of ethnomedicine, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia oligantha Merr. is an ethnomedicine plant mainly distributed in Guangdong and Hainan, China. It has the effects of heat-clearing and detoxicating, which has been used by local ethnic minorities to treat a variety of diseases, including inflammation, internal heat, toothache and scald.

THE AIM OF THE REVIEW

This review summarizes and discusses the progress of the chemical compounds and biological activities of G. oligantha that have been studied in recent years to provide the direction for the prospective research and applications of G. oligantha.

MATERIALS AND METHODS

The relevant literature about G. oligantha was accessible from ancient Chinese medical books and records, theses, as well as major scientific databases such as Google Scholar, PubMed, Web of Science, ScienceDirect, SciFinder, Baidu Scholar and China National Knowledge Infrastructure (CNKI).

RESULTS

To date, more than 150 chemical compounds were isolated from this plant, including xanthones, volatile oil, fatty acid, benzofurane derivative and biphenyl compounds. Xanthones are the main bioactive compounds that exhibit diverse biological effects, such as antitumor, analgesic, anti-inflammatory, antioxidative, neuroprotective, antimalarial and antibacterial effects, which are consistent with its traditional uses as a folk medicine. Modern pharmacological studies show that these compounds participate in a variety of signaling pathways underlying different pathophysiologies, making them a valuable medicinal resource.

CONCLUSION

G. oligantha is an ethnomedicine with a long history. However, due to regional and cultural constraints, the popularisation and use of ethnomedicine are still limited. Modern pharmacological and chemical research suggest that G. oligantha contains a variety of bioactive compounds and showed diverse biological functions, which is worthy of comprehensive and in-depth research. This review summarizes and discusses the recent progress in studies on G. oligantha, looking forward to promote further research and sustainable development of folk medicinal plants.

A polypeptide inhibitor of calcineurin blocks the calcineurin-NFAT signalling pathway in vivo and in vitro

Calcineurin (CN) controls the immune response by regulating nuclear factor of activated T cells (NFAT). Inhibition of CN function is an effective treatment for immune diseases. The PVIVIT peptide is an artificial peptide based on the NFAT-PxIxIT motif, which exhibits stronger binding to CN. A bioactive peptide (named pep4) that inhibits the CN/NFAT interaction was designed. Pep4 contains a segment of A238L as the linker and the LxVP motif and PVIVIT motif as CN binding sites. Pep4 has strong binding capacity to CN and inhibits CN activity competitively. 11-arginine-modified pep4 (11 R-pep4) inhibits the nuclear translocation of NFAT and reduces the expression of IL-2. 11 R-pep4 improves the pathological characteristics of asthmatic mice to a certain extent. The above results indicated that pep4 is a high-affinity CN inhibitor. These findings will contribute to the discovery of new CN inhibitors and promising immunosuppressive drugs.

Garcinol Is an HDAC11 Inhibitor

Garcinol is a natural product from the Garcinia Indica fruit and is well-known as an antioxidant, anti-inflammatory, and anticancer agent. However, the understanding of its mechanism of action is still incomplete. It has been reported to be a histone acetyltransferase (HAT) inhibitor. Here, we surprisingly found that garcinol is a potent histone deacetylase 11 (HDAC11) inhibitor (IC₅₀ ∼ 5 μM in vitro with the HPLC assay and IC₅₀ ∼ 10 μM in the cellular SHMT2 fatty acylation assay), which is comparable to previously reported HDAC11 inhibitors. Additionally, among all the HDACs tested, garcinol specifically inhibits HDAC11 over other HDACs. HDAC11 is the only class IV HDAC, and there are very few inhibitors available for it. Therefore, this study provides a new HDAC11 inhibitor lead from natural products and may help explain the various biological activities of garcinol.

Neuroprotection Against Parkinson's Disease Through the Activation of Akt/GSK3β Signaling Pathway by Tovophyllin A

Parkinson’s disease (PD) is one of the most prevalent and life-threatening neurodegenerative disease and mainly characterized by lack of sufficient dopaminergic neurons in the substantia nigra pars compacta (SNc). Although current treatments help to alleviate clinical symptoms, effective therapies preventing neuronal loss remain scarce. Tovophyllin A (TA), one of the xanthones extracted from Garcinia mangostana L. (GM), has recently been reported to play a beneficial role in the therapy of neurodegenerative diseases. In our research, we explored whether TA has protective effects on dopaminergic neurons in PD models. We found that TA significantly reduced apoptotic cell death in primary cortical neurons treated with 1-methyl-4-phenyl pyridinium (MPP⁺) or paraquat (PQ) in the in vitro PD model. In an in vivo acute PD model induced by 1-methyl4-phenyl-1,2,3,5-tetrahydropyridine (MPTP) treatment, TA also attenuated the resulting behavioral dysfunctions and dopaminergic neuron loss. In the collected brain tissues, TA increased the phosphorylation of Akt and GSK-3β, which may be related to TA-mediated dopaminergic neuronal protective effects. In summary, our results illustrated that TA is a powerful cytoprotective agent for dopaminergic neurons in the MPTP-induced PD model, suggesting TA as a possible therapeutic candidate for PD.

Natural Products and Their Bioactive Compounds: Neuroprotective Potentials against Neurodegenerative Diseases

In recent years, natural products, which originate from plants, animals, and fungi, together with their bioactive compounds have been intensively explored and studied for their therapeutic potentials for various diseases such as cardiovascular, diabetes, hypertension, reproductive, cancer, and neurodegenerative diseases. Neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis are characterized by the progressive dysfunction and loss of neuronal structure and function that resulted in the neuronal cell death. Since the multifactorial pathological mechanisms are associated with neurodegeneration, targeting multiple mechanisms of actions and neuroprotection approach, which involves preventing cell death and restoring the function to damaged neurons, could be promising strategies for the prevention and therapeutic of neurodegenerative diseases. Natural products have emerged as potential neuroprotective agents for the treatment of neurodegenerative diseases. This review focused on the therapeutic potential of natural products and their bioactive compounds to exert a neuroprotective effect on the pathologies of neurodegenerative diseases.

Chemical and Biological Aspects of Garcinol and Isogarcinol: Recent Developments

The natural polyisoprenylated benzophenone derivatives garcinol and isogarcinol are secondary plant metabolites isolated from various Garcinia species including Garcinia indica. This review takes stock of the recent chemical and biological research into these interesting natural compounds over the last five years. New biological sources and chemical syntheses are discussed followed by new insights into the activity of garcinol and isogarcinol against cancer, pathogenic bacteria, parasite infections and various inflammatory diseases.

The antioxidant activity and genotoxicity of isogarcinol

The antioxidant activity and genotoxicity of isogarcinol were assessed by several in vitro tests. Its IC₅₀ values for DPPH and ABTS were 36.3 ± 3.35 µM and 16.6 ± 3.98 µM, respectively, which were all lower than those of VC and BHT. Isogarcinol had no cyctotoxic or promotional activities at 1-10 µM in the CCK-8 assay, and negligible genotoxic effects at 50-500 µM on HepG2 cells by the single-cell gel electrophoresis assay. Pre-incubation of the cells with 0.5-1.5 µM isogarcinol, before exposure to H₂O₂, significantly increased cell viability in a concentration-dependent manner. Isogarcinol also reduced intercellular reactive oxygen species accumulation, lactate dehydrogenase release and malondialdehyde levels, and increased superoxide dismutase activity and glutathione levels. Western-blot analysis revealed that it up-regulated pro-caspase-3 and reduced cleaved caspase-3 during H₂O₂-induced oxidative stress. All the above results indicate that isogarcinol promises to be useful as a natural antioxidant.

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.

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.

Isogarcinol Extracted from Garcinia mangostana L. Ameliorates Imiquimod-Induced Psoriasis-like Skin Lesions in Mice

Isogarcinol (YDIS), a natural compound extracted from Garcinia mangostana L., has a significant immunosuppressive effect on systemic lupus erythematosus and rheumatoid arthritis. This paper reports that it reduced imiquimod-induced psoriasis-like skin lesions in mice. It strongly attenuated the aberrant proliferation and differentiation of keratinocytes. Moreover, the expression of genes involving the interleukin-23 (IL-23)/T-helper 17 (Th17) axis was significantly inhibited in the dorsal skin of the YDIS-treated mice, as was that of the other pro-inflammatory factors TNF-α, IL-2, and even interferon (IFN)-γ. Furthermore, YDIS prevented the abnormal distribution of T cell types and suppressed the differentiation of CD4⁺ T cells into Th17 cells in the spleens of mice exposed to imiquimod. Interestingly, it elevated numbers of regulatory T cells (Tregs) in the spleen and boosted IL-10 expression in the skin. In agreement with the above, YDIS increased serum IL-10 and reduced serum IL-17. It also caused less damage to the liver and, especially, kidneys of mice than cyclosporine A (CsA). In vitro, YDIS caused more death of HaCaT keratinocytes than CsA. It also strongly inhibited inflammatory factor expression in lipopolysaccharide (LPS)-stimulated HaCaT cells. These findings suggest that YDIS is a promising immunosuppressive agent for treating psoriasis.