α-Mangostin: a dietary antioxidant derived from the pericarp of Garcinia mangostana L. inhibits pancreatic tumor growth in xenograft mouse model

Prospects of compounds of herbal plants as anticancer agents: a comprehensive review from molecular pathways

Cancer refers to the proliferation and multiplication of aberrant cells inside the human body, characterized by their capacity to proliferate and infiltrate various anatomical regions. Numerous biochemical pathways and signaling molecules have an impact on the cancer auto biogenesis process. The regulation of crucial cellular processes necessary for cell survival and proliferation, which are triggered by phytochemicals, is significantly influenced by signaling pathways. These pathways or components are regulated by phytochemicals. Medicinal plants are a significant reservoir of diverse anticancer medications employed in chemotherapy. The anticancer effects of phytochemicals are mediated by several methods, including induction of apoptosis, cessation of the cell cycle, inhibition of kinases, and prevention of carcinogenic substances. This paper analyzes the phytochemistry of seven prominent plant constituents, namely, alkaloids, tannins, flavonoids, phenols, steroids, terpenoids, and saponins, focusing on the involvement of the MAPK/ERK pathway, TNF signaling, death receptors, p53, p38, and actin dynamics. Hence, this review has examined a range of phytochemicals, encompassing their structural characteristics and potential anticancer mechanisms. It has underscored the significance of plant-derived bioactive compounds in the prevention of cancer, utilizing diverse molecular pathways. In addition, this endeavor also seeks to incentivize scientists to carry out clinical trials on anticancer medications derived from plants.

Formulation of 1% α-mangostin in orabase gel induces apoptosis in oral squamous cell carcinoma

BACKGROUND

Plant-derived compounds have chemopreventive properties to be used as alternative medicine. Pericarp of Mangosteen (Garcinia mangostana Linn.), a tropical fruit in Southeast Asia contains a phytochemical α-mangostin (α-MG) that demonstrates potent anticancer effects against various types of cancer. α-MG has been reported to be the most effective agent in human cancer cell lines. The objectives of this study were to develop oral gel formulations containing α-MG and determine their (1) anticancer activity, (2) anti-HPV-16 and antimicrobial activities, (3) nitric oxide (NO) inhibitory activity, and (4) wound healing effect.

METHODS

Formulations of oral gel containing α-MG were developed. Anticancer activity on SCC-25 was assessed. Apoptotic induction was determined using flow cytometry technique. Antiviral activity against HPV-16 pseudovirus and antimicrobial activity against S. mutans, P. gingivalis and C. albicans were investigated. NO inhibition was carried out. Fibroblast cell migration was determined by in vitro scratch assay.

RESULTS

The formulation of 1% α-MG in orabase gel demonstrated anticancer activity by promoting apoptosis in SCC-25. The induction of apoptotic activity was dose dependent with pronounced effect in late apoptosis. The formulation appeared to reduce cell viability of oral keratinocytes (OKC). At CC50 it showed an inhibition against HPV-16 pseudovirus infection. The formulation had no antimicrobial activity against S. mutans, P. gingivalis and C. albicans. No significant NO inhibitory activity and wound healing effects were found.

CONCLUSIONS

1% α-MG in orabase gel exhibited anticancer activity by inducing apoptosis although low level of cytotoxicity observed in OKC was present. The appropriate carrier for novel nano-particles targeting cancer cells should be further investigated.

Garcinia mangostana L. Pericarp Extract and Its Active Compound α-Mangostin as Potential Inhibitors of Immune Checkpoint Programmed Death Ligand-1

α-Mangostin, a major xanthone found in mangosteen (Garcinia mangostana L., Family Clusiaceae) pericarp, has been shown to exhibit anticancer effects through multiple mechanisms of action. However, its effects on immune checkpoint programmed death ligand-1 (PD-L1) have not been studied. This study investigated the effects of mangosteen pericarp extract and its active compound α-mangostin on PD-L1 by in vitro and in silico analyses. HPLC analysis showed that α-mangostin contained about 30% w/w of crude ethanol extract of mangosteen pericarp. In vitro experiments in MDA-MB-231 triple-negative breast cancer cells showed that α-mangostin and the ethanol extract significantly inhibit PD-L1 expression when treated for 72 h with 10 µM or 10 µg/mL, respectively, and partially inhibit glycosylation of PD-L1 when compared to untreated controls. In silico analysis revealed that α-mangostin effectively binds inside PD-L1 dimer pockets and that the complex was stable throughout the 100 ns simulation, suggesting that α-mangostin stabilized the dimer form that could potentially lead to degradation of PD-L1. The ADMET prediction showed that α-mangostin is lipophilic and has high plasma protein binding, suggesting its greater distribution to tissues and its ability to penetrate adipose tissue such as breast cancer. These findings suggest that α-mangostin-rich mangosteen pericarp extract could potentially be applied as a functional ingredient for cancer chemoprevention.

Nanomedicine and epigenetics: New alliances to increase the odds in pancreatic cancer survival

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers worldwide, primarily due to its robust desmoplastic stroma and immunosuppressive tumor microenvironment (TME), which facilitate tumor progression and metastasis. In addition, fibrous tissue leads to sparse vasculature, high interstitial fluid pressure, and hypoxia, thereby hindering effective systemic drug delivery and immune cell infiltration. Thus, remodeling the TME to enhance tumor perfusion, increase drug retention, and reverse immunosuppression has become a key therapeutic strategy. In recent years, targeting epigenetic pathways has emerged as a promising approach to overcome tumor immunosuppression and cancer progression. Moreover, the progress in nanotechnology has provided new opportunities for enhancing the efficacy of conventional and epigenetic drugs. Nano-based drug delivery systems (NDDSs) offer several advantages, including improved drug pharmacokinetics, enhanced tumor penetration, and reduced systemic toxicity. Smart NDDSs enable precise targeting of stromal components and augment the effectiveness of immunotherapy through multiple drug delivery options. This review offers an overview of the latest nano-based approaches developed to achieve superior therapeutic efficacy and overcome drug resistance. We specifically focus on the TME and epigenetic-targeted therapies in the context of PDAC, discussing the advantages and limitations of current strategies while highlighting promising new developments. By emphasizing the immense potential of NDDSs in improving therapeutic outcomes in PDAC, our review paves the way for future research in this rapidly evolving field.

Immunomodulatory activity of semen Ziziphi Spinosae protein: a potential plant protein functional food raw material

Semen Ziziphi Spinosae protein (SZSP) is a new plant protein resource with good food functional properties and health care function. However, the biological activity of SZSP has not been further studied, which greatly limits the development and utilization of SZSP in the food industry. The aim of this study was to investigate the protective effect of SZSP on immunosuppressed mice and its inhibitory effect on immune-stimulated RAW264.7 cells. The results demonstrated that SZSP remarkably improved the immunomodulatory secretion in serum (interleukin-2, tumor necrosis factor-α [TNF-α], interferon-γ, immunoglobulin-A, immunoglobulin-G, immunoglobulin-M) and primary macrophages (nitric oxide, interleukin-1β, TNF-α) and promoted the NK-cell killing activity of primary splenocytes in CTX-induced immunosuppression mice. Immunohistochemical analysis results indicated that the secretion of CD₄⁺ and CD₈⁺ in the spleen and thymus can be regulated by SZSP, leading to inhibition of the damage induced by cyclophosphamide in mice. Meanwhile, in order to clarify the immunomodulatory mechanism of SZSP, we showed that SZSP significantly inhibited the secretion of NO, interleukin-6, and TNF-α and reduced the phosphorylation expression of p-ERK, p-JNK, and p-IκBα in lipopolysaccharide-stimulated RAW264.7 cells. Therefore, the immunomodulatory effect of SZSP may be related to the activation of MAPKs and NF-κB signaling pathways. Based on the above studies, the preliminary purification of SZSP was continued, and S1F2G1 with immunomodulatory activity was obtained. Taken together, SZSP has an immunoregulatory effect in vivo and in vitro and may be a favorable candidate of functional food raw material for regulating immune responses.

Effects of Mangosteen (Garcinia mangostana) Peel Extract Loaded in Nanoemulsion on Growth Performance, Immune Response, and Disease Resistance of Nile Tilapia (Oreochromis niloticus) against Aeromonas veronii Infection

Nanotechnology can enhance nutrient delivery and bioavailability; hence, it has recently been considered the most practical alternative technology for nutritional supplements and disease control in fish farming. The present study was designed to evaluate the effects of mangosteen peel extract loaded in nanoemulsion (MSNE) on the inhibition of A. veronii (in vitro) and in vivo growth performance, serum biochemical parameters, the immune response, and the disease resistance of Nile tilapia (Oreochromis niloticus) against A. veronii challenge. The particle size, polydispersity index, and particle surface charge of MSNE were 151.9 ± 1.4 nm, >0.3, and -30 mV, respectively. Furthermore, MSNE, mangosteen peel extract (MPE), and nanoemulsion (NE) improved the antimicrobial activity against A. veronii. Fish fed MSNE, MPE, and NE-supplemented diets had a significantly lower (p < 0.05) feed conversion ratio (FCR) and higher specific growth rate (SGR) than fish fed the control diet. Furthermore, the MSNE had significantly higher serum glucose and protein levels than the control group in Nile tilapia. Total immunoglobulin, serum lysozyme, alternative complement activity, and survival of Nile tilapia fed with MSNE were significantly higher (p < 0.05) than the control diet. Therefore, MSNE has the potential to be employed as a supplement in sustainable Nile tilapia farming.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

JI017 Induces Cell Autophagy and Apoptosis via Elevated Levels of Reactive Oxygen Species in Human Lung Cancer Cells

Lung cancer is one of the most common malignant tumors and a leading cause of cancer-related death in the worldwide. Various anticancer drugs, such as cisplatin and pemetrexed, have been developed for lung cancer treatment but due their drug resistance and side effects, novel treatments need to be developed. In this study, the efficacy of the natural drug JI017, which is known to have few side effects, was tested in lung cancer cells. JI017 inhibited A549, H460, and H1299 cell proliferation. JI017 induced apoptosis, regulated apoptotic molecules, and inhibited colony formation. Additionally, JI017 increased intracellular ROS generation. JI017 downregulated PI3K, AKT, and mTOR expression. JI017 increased the cytosolic accumulation of LC3. We found that JI017 promoted apoptosis through ROS-induced autophagy. Additionally, the xenograft tumor size was smaller in JI017-treated mice. We found that JI017 treatment increased MDA concentrations, decreased Ki-67 protein levels, and increased cleaved caspase-3 and LC3 levels in vivo. JI017 decreased cell proliferation and increased apoptosis by inducing autophagy signaling in H460 and H1299 lung cancer cells. Targeting JI017 and autophagy signaling could be useful in lung cancer treatment.

Mangosteen for malignancy prevention and intervention: Current evidence, molecular mechanisms, and future perspectives

Mangosteen (Garcinia mangostana L.), also known as the "queen of fruits", is a tropical fruit of the Clusiacea family. While native to Southeast Asian countries, such as Thailand, Indonesia, Malaysia, Myanmar, Sri Lanka, India, and the Philippines, the fruit has gained popularity in the United States due to its health-promoting attributes. In traditional medicine, mangosteen has been used to treat a variety of illnesses, ranging from dysentery to wound healing. Mangosteen has been shown to exhibit numerous biological and pharmacological activities, such as antioxidant, anti-inflammatory, antibacterial, antifungal, antimalarial, antidiabetic, and anticancer properties. Disease-preventative and therapeutic properties of mangosteen have been ascribed to secondary metabolites called xanthones, present in several parts of the tree, including the pericarp, fruit rind, peel, stem bark, root bark, and leaf. Of the 68 mangosteen xanthones identified so far, the most widely-studied are α-mangostin and γ-mangostin. Emerging studies have found that mangosteen constituents and phytochemicals exert encouraging antineoplastic effects against a myriad of human malignancies. While there are a growing number of individual research papers on the anticancer properties of mangosteen, a complete and critical evaluation of published experimental findings has not been accomplished. Accordingly, the objective of this work is to present an in-depth analysis of the cancer preventive and anticancer potential of mangosteen constituents, with a special emphasis on the associated cellular and molecular mechanisms. Moreover, the bioavailability, pharmacokinetics, and safety of mangosteen-derived agents together with current challenges and future research avenues are also discussed.

Apogossypolone Inhibits Cell Proliferation and Epithelial-Mesenchymal Transition in Cervical Cancer via Activating DKK3

Apogossypolone (ApoG2), a novel derivative of gossypol lacking of two aldehyde groups, exhibits anti-tumor effects. However, the mechanisms by which ApoG2 regulates cervical cancer (CC) cells remain unclear. In this study, we treated two CC cell lines (CaSki and HeLa) with an increasing concentration of ApoG2 for 24 h. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, flow cytometry and transwell invasion assay were utilized to detect cell proliferation, apoptosis and invasion in vitro. We first observed that ApoG2 inhibited cell proliferation, invasion and epithelial-to-mesenchymal transition (EMT) process in CC cells, along with upregulation of Dickkopf Wnt signaling pathway inhibitor 3 (DKK3) in a dose-dependent manner. The immunohistochemistry confirmed the downregulation of DKK3 in tumor tissues. Moreover, DKK3 was correlated with FIGO stage and lymph node metastasis. Functionally, DKK3 overexpression significantly suppressed cell viability, colony formation and invasion, but promoted apoptosis in CaSki and HeLa cells. Overexpression of DKK3 upregulated the protein levels of cleaved caspase-3 and E-cadherin, but downregulated the protein levels of Bcl-2, N-cadherin and Vimentin. Furthermore, DKK3 knockdown reversed the suppressive effects of ApoG2 on CaSki cell proliferation, invasion and EMT markers, while DKK3 overexpression enhanced these effects. In addition, ApoG2 treatment inhibited CC xenograft tumor growth and upregulated the protein levels of DKK3, cleaved caspase-3 and E-cadherin. In conclusions, these findings suggested that ApoG2 could effectively inhibit the growth and invasion of CC cells at least partly by activating DKK3.

ALPHA-MANGOSTIN (Garcinia mangostana Linn.) AND ITS POTENTIAL APPLICATION IN MITIGATING CHRONIC WOUND HEALING

Wound healing is a complex and dynamic cellular process to restore tissue function. Current treatments for chronic wounds especially diabetic ulcers are expensive, with adverse effects. Recently, numerous researchers have focused on the potential effect of natural products on wound healing. One of them is mangosteen (Garcinia mangostana Linn). It is a well-known tropical fruit that is native to Southeast Asia. The active ingredient of mangosteen pericarp contains xanthones that exhibit a wide range of pharmacological activities, including anti-inflammatory and anti-bacterial properties which are the core elements needed in wound healing. Firstly, this review discusses the concepts of abnormal and normal wound healing mechanisms. Then an in depth observation of the pharmacological activities of mangosteen and its derivatives was presented to study their potentially beneficial applications in the treatment of chronic wound healing which is a contemporary medical issue.

Suppressive effect of α-mangostin for cancer stem cells in colorectal cancer via the Notch pathway

Background

Since colon cancer stem cells (CSCs) play an important role in chemoresistance and in tumor recurrence and metastasis, targeting of CSCs has emerged as a sophisticated strategy for cancer therapy. α-mangostin (αM) has been confirmed to have antiproliferative and apoptotic effects on cancer cells. This study aimed to evaluate the selective inhibition of αM on CSCs in colorectal cancer (CRC) and the suppressive effect on 5-fluorouracil (5-FU)-induced CSCs.

Methods

The cell viability assay was performed to determine the optimal concentration of αM. A sphere forming assay and flow cytometry with CSC markers were carried out to evaluate the αM-mediated inhibition of CSCs. Western blot analysis and quantitative real-time PCR were performed to investigate the effects of αM on the Notch signaling pathway and colon CSCs. The in vivo anticancer efficacy of αM in combination with 5-FU was investigated using a xenograft mouse model.

Results

αM inhibited the cell viability and reduced the number of spheres in HT29 and SW620 cells. αM treatment decreased CSCs and suppressed the 5-FU-induced an increase in CSCs on flow cytometry. αM markedly suppressed Notch1, NICD1, and Hes1 in the Notch signaling pathway in a time- and dose-dependent manner. Moreover, αM attenuated CSC markers CD44 and CD133, in a manner similar to that upon DAPT treatment, in HT29 cells. In xenograft mice, the tumor and CSC makers were suppressed in the αM group and in the αM group with 5-FU treatment.

Conclusion

This study shows that low-dose αM inhibits CSCs in CRC and suppresses 5-FU–induced augmentation of CSCs via the Notch signaling pathway.

Synthesis and Properties of α-Mangostin and Vadimezan Conjugates with Glucoheptoamidated and Biotinylated 3rd Generation Poly(amidoamine) Dendrimer, and Conjugation Effect on Their Anticancer and Anti-Nematode Activities

α-Mangostin and vadimezan are widely studied potential anticancer agents. Their biological activities may be improved by covalent bonding by amide or ester bonds with the third generation poly(amidoamine) (PAMAM) dendrimer, substituted with α-D-glucoheptono-1,4-lactone and biotin. Thus, conjugates of either ester- (G3gh4B5V) or amide-linked (G32B12gh5V) vadimezan, and equivalents of α-mangostin (G3gh2B5M and G32B12gh5M, respectively), were synthesized, characterized and tested in vitro against cancer cells: U-118 MG glioma, SCC-15 squamous carcinoma, and BJ normal human fibroblasts growth, as well as against C. elegans development. α-Mangostin cytotoxicity, stronger than that of Vadimezan, was increased (by 2.5-9-fold) by conjugation with the PAMAM dendrimer (with the amide-linking being slightly more effective), and the strongest effect was observed with SCC-15 cells. Similar enhancement of toxicity resulting from the drug conjugation was observed with C. elegans. Vadimezan (up to 200 µM), as well as both its dendrimer conjugates, was not toxic against both the studied cells and nematodes. It showed an antiproliferative effect against cancer cells at concentrations ≥100 µM. This effect was significantly enhanced after conjugation of the drug with the dendrimer via the amide, but not the ester bond, with G32B12gh5V inhibiting the proliferation of SCC-15 and U-118 MG cells at concentrations ≥4 and ≥12 μM, respectively, without a visible effect in normal BJ cells. Thus, the drug delivery system based on the PAMAM G3 dendrimer containing amide bonds, partially-blocked amino groups on the surface, larger particle diameter and higher zeta potential can be a useful tool to improve the biological properties of transported drug molecules.

The purple mangosteen (Garcinia mangostana): Defining the anticancer potential of selected xanthones

The purple mangosteen (Garcinia mangostana) is a popular Southeast Asian fruit that has been used traditionally for its health promoting benefits for years. Unique to the mangosteen are a class of phytochemicals known as xanthones that have been reported to display significant anti-cancer and anti-tumor activities, specifically through the promotion of apoptosis, targeting of specific cancer-related proteins, or modulation of cell signaling pathways. α-Mangostin, the most abundant xanthone isolated from the mangosteen, has received substantial attention as it has proven to be a potent phytochemical, specifically as an anticancer agent, in numerous different cancer cell studies and cancer animal models. While the mechanisms for these anticancer effects have been reported in many studies, lesser xanthones, including gartanin, β-mangostin, γ-mangostin, garcinone C, and garcinone E, and mangosteen extracts from the pericarp, roots, rind, and stem show promise for their anticancer activity but their mechanisms of action are not as well developed and remain to be determined. Mangosteen products appear safe and have been well tolerated in human clinical trials where they show antioxidant activity, though their clinical anticancer activity has not yet been evaluated. This review summarizes the work that has been done to explore and explain the anticancer and antitumor activities of α-mangostin, lesser xanthones, and mangosteen extracts in vitro, in vivo, and in humans in various cancers.

Emerging agents that target signaling pathways to eradicate colorectal cancer stem cells

Colorectal cancer (CRC) represents the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide. The modern concept of cancer biology indicates that cancer is formed of a small population of cells called cancer stem cells (CSCs), which present both pluripotency and self-renewal properties. These cells are considered responsible for the progression of the disease, recurrence and tumor resistance. Interestingly, some cell signaling pathways participate in CRC survival, proliferation, and self-renewal properties, and most of them are dysregulated in CSCs, including the Wingless (Wnt)/β-catenin, Notch, Hedgehog, nuclear factor kappa B (NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), peroxisome proliferator-activated receptor (PPAR), phosphatidyl-inositol-3-kinase/Akt/mechanistic target of rapamycin (PI3K/Akt/mTOR), and transforming growth factor-β (TGF-β)/Smad pathways. In this review, we summarize the strategies for eradicating CRC stem cells by modulating these dysregulated pathways, which will contribute to the study of potential therapeutic schemes, combining conventional drugs with CSC-targeting drugs, and allowing better cure rates in anti-CRC therapy.

Alpha Mangostin Derived from Garcinia magostana Linn Ameliorates Cardiomyocyte Hypertrophy and Fibroblast Phenotypes in Vitro

Cardiac hypertrophy and fibrosis are significant risk factors for chronic heart failure (HF). Since pharmacotherapy agents targeting these processes have not been established, we investigated the effect of alpha-magostin (α-man) on cardiomyocyte hypertrophy and fibrosis in vitro. Primary cultured cardiomyocytes and cardiac fibroblasts were prepared from neonatal rats. After α-man treatment, phenylephrine (PE) and transforming growth factor-beta (TGF-β) were added to the cardiomyocytes and cardiac fibroblasts to induce hypertrophic and fibrotic responses, respectively. Hypertrophic responses were assessed by measuring the cardiomyocyte surface area and hypertrophic gene expression levels. PE-induced phosphorylation of Akt, extracellular signal-regulated kinase (ERK)1/2, and p38 was examined by Western blotting. Fibrotic responses were assessed by measuring collagen synthesis, fibrotic gene expression levels, and myofibroblast differentiation. In addition, TGF-β-induced reactive oxygen species (ROS) production was investigated. In cultured cardiomyocytes, α-man significantly suppressed PE-induced increases in the cardiomyocyte surface area, and the mRNA levels (atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP)). Treatment with α-man significantly suppressed PE-induced Akt phosphorylation, but not ERK and p38 phosphorylation. In cultured cardiac fibroblasts, α-man significantly suppressed TGF-β-induced increases in L-proline incorporation, mRNA levels (POSTN and alpha-smooth muscle actin (α-SMA)), and myofibroblast differentiation. Additionally, it significantly inhibited TGF-β-induced reduced nicotinamide adenine dinucleotide phosphate oxidase4 (NOX4) expression and ROS production in cardiac fibroblasts. Treatment with α-man significantly ameliorates hypertrophy by inhibiting Akt phosphorylation in cardiomyocytes and fibrosis by inhibiting NOX4-generating ROS in fibroblasts. These findings suggest that α-man is a possible natural product for the prevention of cardiac hypertrophy and fibrosis.

Anti-Acanthamoeba synergistic effect of chlorhexidine and Garcinia mangostana extract or α-mangostin against Acanthamoeba triangularis trophozoite and cyst forms

Acanthamoeba spp. can cause amoebic keratitis (AK). Chlorhexidine is effective for AK treatment as monotherapy, but with a relative failure on drug bioavailability in the deep corneal stroma. The combination of chlorhexidine and propamidine isethionate is recommended in the current AK treatment. However, the effectiveness of treatment depends on the parasite and virulence strains. This study aims to determine the potential of Garcinia mangostana pericarp extract and α-mangostin against Acanthamoeba triangularis, as well as the combination with chlorhexidine in the treatment of Acanthamoeba infection. The minimal inhibitory concentrations (MICs) of the extract and α-mangostin were assessed in trophozoites with 0.25 and 0.5 mg/mL, for cysts with 4 and 1 mg/mL, respectively. The MIC of the extract and α-mangostin inhibited the growth of A. triangularis trophozoites and cysts for up to 72 h. The extract and α-mangostin combined with chlorhexidine demonstrated good synergism, resulting in a reduction of 1/4-1/16 of the MIC. The SEM results showed that Acanthamoeba cells treated with a single drug and its combination caused damage to the cell membrane and irregular cell shapes. A good combination displayed by the extract or α-mangostin and chlorhexidine, described for the first time. Therefore, this approach is promising as an alternative method for the management of Acanthamoeba infection in the future.

Enhancement of α-Mangostin Wound Healing Ability by Complexation with 2-Hydroxypropyl-β-Cyclodextrin in Hydrogel Formulation

α-Mangostin (α-M), one of the active compounds in Garcinia mangostana peel, has been effectively used in wound healing. However, its poor solubility in aqueous solution causes low bioavailability for skin ulcers, hindering its application in wound healing. The aim of this study was to improve the solubility of α-M through complex formation with 2-hydroxypropyl-β-cyclodextrin (α-M/HP-β-CD CX) and to evaluate the healing activity of the complex. The α-M/HP-β-CD CX was incorporated in a sodium carboxymethylcellulose hydrogel (α-M/HP-β-CD CX HG), and the in vivo healing activity was examined in mice. Evaluation of α-M/HP-β-CD CX HG, including organoleptic evaluation, homogeneity, pH, spreadability, swelling ratio, consistency, scanning electron microscopy (SEM), and in vitro drug release, was carried out. The complex formation of α-M/HP-β-CD CX was confirmed by FTIR and PXRD analysis. The solubility of the α-M/HP-β-CD CX in water linearly increased about 11.7-fold compared to α-M alone, and by 3.5-fold compared to the α-M/HP-β-CD physical mixture (α-M/HP-β-CD CX PM). The α-M/HP-β-CD CX HG was homogenous, the pH was found to be in the neutral range, the spread area was 5 cm, and the consistency was stable until 14 days. SEM analysis showed that α-M/HP-β-CD CX HG surged due to the porous structure of the HG. In addition, in vitro release of α-M from α-M/HP-β-CD CX HG was considerably increased compared to α-M/HP-β-CD PM HG and α-M HG. Notably, in vivo evaluation in mice showed that α-M/HP-β-CD CX HG significantly accelerated the wound healing ability compared to other HGs. Thus, α-M/HP-β-CD CX HG has potential as a new formulation of α-M for wound healing therapy.

α-Mangostin-encapsulated PLGA nanoparticles inhibit colorectal cancer growth by inhibiting Notch pathway

Colorectal cancer (CRC) is the fourth leading cause of cancer‐related mortality. Recent studies have stated that Notch signalling is highly activated in cancer stem cells (CSCs) and plays an important role in the development and progression of CRC. Like normal colorectal epithelium, CRCs are organized hierarchically and include populations of CSCs. In order to enhance the biological activity of α‐mangostin, we formulated α‐mangostin‐encapsulated PLGA nanoparticles (Mang‐NPs) and examined the molecular mechanisms by which Mang‐NPs inhibit CRC cell viability, colony formation, epithelial‐mesenchymal transition (EMT) and induce apoptosis. Mang‐NPs inhibited cell viability, colony formation and induced apoptosis. Mang‐NPs also inhibited EMT by up‐regulating E‐cadherin and inhibiting N‐cadherin and transcription factors Snail, Slug and Zeb1. As dysregulated signalling through the Notch receptors promotes oncogenesis, we measured the effects of Mang‐NPs on Notch pathway. Mang‐NPs inhibited Notch signalling by suppressing the expression of Notch receptors (Notch1 and Notch2), their ligands (Jagged 1 and DLL4), γ‐secretase complex protein (Nicastrin) and downstream target (Hes‐1). Notch receptor signalling regulates cell fate determination in stem cell population. Finally, Mang‐NPs inhibited the self‐renewal capacity of CSCs, stem cell markers (CD133, CD44, Musashi and LGR5) and pluripotency maintaining factors (Oct4, Sox‐2, KLF‐4, c‐Myc and Nanog). Overall, our data suggest that Mang‐NPs can inhibit CRC growth, EMT and CSCs’ population by suppressing Notch pathway and its target. Therefore, Mang‐NPs can be used for the treatment and prevention of CRC.

Isocorydine decrease gemcitabine-resistance by inhibiting epithelial-mesenchymal transition via STAT3 in pancreatic cancer cells

Gemcitabine is widely used as an anticancer chemotherapy drug for a variety of solid tumors, and it has become the standard treatment option for locally advanced and metastatic pancreatic cancer. However, pancreatic cancer cells develop resistance to gemcitabine after a few weeks of treatment, resulting in poor therapeutic effects. Isocorydine (ICD) is a typical natural aporphine alkaloid, and ICD and its derivatives inhibit the proliferation of many types of cancer cells in vitro. In this study, ICD was found to synergistically inhibit cell viability with gemcitabine in pancreatic cancer cells. A microarray analysis showed that ICD can inhibit the upregulation of STAT3 and EMT in pancreatic cancer cells induced by gemcitabine. STAT3 is closely related to tumor EMT, migration and invasion. After knocking down the expression of STAT3 in pancreatic cancer cells, the combination index (CI) of ICD and gemcitabine decreased. ICD can reverse the increase in the expression of EMT-related transcription factors and proteins caused by gemcitabine, thereby inhibiting the enhanced cell migration and invasion ability caused by gemcitabine. Finally, the synergistic treatment effect of the combination treatment of ICD and gemcitabine in pancreatic cancer cells was confirmed in established xenograft models.

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.

Alpha Mangostin promotes myogenic differentiation of C2C12 mouse myoblast cells

Mangosteen, a fruit mainly produced in Southeast Asia, has been used as food and as an antipyretic and for treating skin diseases. The xanthones contained in mangosteen have many physiological activities including melanin suppression and anticancer activities, but little is known about the physiological effects of the most abundant xanthone, α-mangostin (α-MG) on myoblasts. In this study, we applied α-MG to C2C12 cells that had been induced to differentiate using 2% HS, and analyzed the physiological action of α-MS and the underlying mechanism in the context of myogenic differentiation. α-MG increased the survival rate of C2C12 cells in a concentration-dependent manner. Analysis of the morphological changes in the cells showed that α-MG significantly enhanced the myogenic differentiation of C2C12 myoblasts, whereas the mitochondrial number was only slightly affected. Expression analysis of differentiation-related proteins in C2C12 cells revealed that α-MG promoted the expression of MyoD and Myogenin. Thus, the present study revealed that α-MG improves the survival and myogenic differentiation of C2C12 myoblasts.

Effects of α-Mangostin Derivatives on the Alzheimer's Disease Model of Rats and Their Mechanism: A Combination of Experimental Study and Computational Systems Pharmacology Analysis

α-Mangostin (α-M) is a natural xanthone from the pericarp of fruit Garcinia mangostana and possesses versatile biological activities. α-M has a therapeutic potential to treat Alzheimer's disease (AD) because of its anti-inflammatory, antioxidative, and neuroprotective activities. However, the use of α-M for AD treatment is limited due to its cytotoxic activities and relatively low potency. Modifications of its chemical structure were needed to reduce its cytotoxicity and improve its therapeutic potential against AD. For this purpose, 16 α-M carbamate derivatives were synthesized. An animal model of AD was established, and the effects of AMG-1 on the spatial learning ability and memory ability were evaluated using behavioral tests. The effect on neuropathology was tested by histopathological evaluation, Nissl staining, and silver staining. Computational systems pharmacology analysis using the chemogenomics knowledgebase was applied for network studies. Compound-target, target-pathway, and target-disease networks were constructed, integrating both in silico analysis and reported experimental data. The results show that AMG-1 can demonstrate its therapeutic effects in a one-molecule, multiple-targets manner to remarkably ameliorate neurological changes and reverse behavioral deficits in AD model rats. The improved cognitive function and alleviated neuronal injury can be observed. The ability of AMG-1 to scavenge β-amyloid in the hippocampus was validated in AD model rats.

Cucurbitacin D Overcomes Gefitinib Resistance by Blocking EGF Binding to EGFR and Inducing Cell Death in NSCLCs

In this study, the mechanism of the anticancer effect through which cucurbitacin D (CuD) can overcome gefitinib resistance in NSCLC was investigated. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assay, and cell migration and growth were observed by wound healing and colony formation assays, respectively. Levels of EGFR family members, protein kinase B, extracellular signal-regulated kinase, poly(ADP-ribose) polymerase, and G2/M phase-related proteins were detected by Western blot analysis. Immunofluorescence analysis was used to detect the intracellular expression of p-EGFR. Induction of apoptosis and cell cycle arrest was measured by flow cytometry. Solid-phase binding assays were used to determine binding to the EGFR family. CuD inhibits the phosphorylation of EGFR in gefitinib-resistant NSCLC cells and induces cell death via cell cycle arrest and apoptosis. CuD treatment or EGFR knockdown also suppressed the growth of gefitinib-resistant NSCLC cells. In addition, CuD overcame resistance by blocking EGF binding to EGFR in gefitinib-resistant NSCLC cells. In conclusion, we demonstrate that CuD overcomes gefitinib resistance by reducing the activation of EGFR-mediated survival in NSCLC and by inhibiting the combination of EGF and EGFR.

Doxorubicin and α-Mangostin oppositely affect luminal breast cancer cell stemness evaluated by a new retinaldehyde-dependent ALDH assay in MCF-7 tumor spheroids

According to cancer stem cell theory, only a limited number of self-renewing and cloning cells are responsible for tumor relapse after a period of remittance. The aim of the present study was to investigate the effects of Doxorubicin and α-Mangostin, two antiproliferative drugs, on both tumor bulk and stem cells in multicellular tumor spheroids originated from the luminal MCF-7 breast cancer cell line. A new and original fluorimetric assay was used to selectively measure the activity of the retinaldehyde-dependent isoenzymes of aldehyde dehydrogenase (RALDH), which are markers of a subpopulation of breast cancer stem cells. The administration of 5 μg/ml (12.2 μM) α-Mangostin for 48 h provoked: i) a marked disaggregation of the spheroids, leading to a doubling of their volume (p < 0.01), ii) a 40 % decrease in cell viability (p < 0.01), evaluated by the acid phosphatase assay, and iii) a reduction by more than 90 % of RALDH activity. By contrast, Doxorubicin given for 48 h in the range of 0.1-40 μM did not significantly reduce cell viability and caused only a modest modification of the spheroid morphology. Moreover, 40 μM Doxorubicin increased RALDH activity 2.5-fold compared to the untreated sample. When the two drugs were administered together using 5 μg/ml α-Mangostin, the IC₅₀ of Doxorubicin referred to cell viability decreased six-fold and the RALDH activity was further reduced. In conclusion, the combined administration of Doxorubicin and α-Mangostin provoked a significant cytotoxicity and a remarkable inhibition of RALDH activity in MCF-7 tumor spheroids, suggesting that these drugs could be effective in reducing cell stemness in luminal breast cancer.

α-Mangostin reduced the viability of A594 cells in vitro by provoking ROS production through downregulation of NAMPT/NAD

α-Mangostin (MAN) is a bioactive compound isolated from the inedible pericarp of a tropical fruit mangosteen (Garcinia mangostana Linn). It exhibits notable therapeutic potentials on lung cancers, but the underlying mechanisms are still largely unknown. This study was designed to further explore the mechanisms involved in cytotoxicity of MAN on A549 cells. Apoptosis and cell cycle distribution were analyzed by flow cytometry methods. The fluorescent probes DCFH-DA and JC-1 were used to assess the intracellular reactive oxidative species (ROS) and mitochondrial membrane potential statuses, respectively. The regulation of MAN on relevant pathways was investigated by immunoblotting assays. The results obtained indicated that MAN caused significant apoptosis and cell cycle arrest in A549 cells, which eventually resulted in inhibition on cell proliferation in vitro. All these phenomena were synchronized with escalated oxidative stress and downregulation of nicotinamide phosphoribosyltransferase/nicotinamide adenine dinucleotide (NAMPT/NAD). Supplementation with nicotinamide mononucleotide (NMN) and N-acetylcysteine (NAC) efficiently eased MAN-induced ROS accumulation, and potently antagonized MAN-elicited apoptosis and cell cycle arrest. The pro-apoptotic effect of MAN was further confirmed by increased expressions of cleaved caspase 3, 6, 7, and 9, and its effect on cell cycle progression was validated by the altered expressions of p-p38, p-p53, CDK4, and cyclin D1. The immunoblotting assays also demonstrated that NAC/NMN effectively restored these molecular changes elicited by MAN treatment. Collectively, this study revealed a unique anti-tumor mechanism of MAN by provoking ROS production through downregulation of NAMPT/NAD signaling and further validated MAN as a potential therapeutic reagent for lung cancer treatment.

Current status and contemporary approaches to the discovery of antitumor agents from higher plants

Higher plant constituents have afforded clinically available anticancer drugs. These include both chemically unmodified small molecules and their synthetic derivatives currently used or those in clinical trials as antineoplastic agents, and an updated summary is provided. In addition, botanical dietary supplements, exemplified by mangosteen and noni constituents, are also covered as potential cancer chemotherapeutic agents. Approaches to metabolite purification, rapid dereplication, and biological evaluation including analytical hyphenated techniques, molecular networking, and advanced cellular and animal models are discussed. Further, enhanced and targeted drug delivery systems for phytochemicals, including micelles, nanoparticles and antibody drug conjugates (ADCs) are described herein.

Synergistic anticancer effect of combined use of Trichosanthes kirilowii with cisplatin and pemetrexed enhances apoptosis of H1299 non-small-cell lung cancer cells via modulation of ErbB3

BACKGROUND

Lung cancer is one of the most common malignancies worldwide. To treat lung cancer, various anticancer drugs were developed and tested, but they failed because of drug resistance. In the present study, we tested herbal medicines, such as TK and CuD, as anticancer drugs to decrease side effects and resistance.

METHODS

Cell viability was measured by an MTT assay. Analysis of cell cycle arrest was performed by flow cytometry. Induction of apoptosis by cucurbitacin D was measured by an annexin V-FITC/PI assay. We performed RTK kit analysis. Levels of p-ErbB3, p-STAT3, p-NF-κB, and caspases were measured by western blot analysis. Nuclear staining of ErbB3 was measured by immunocytochemistry. Transcriptional activity of STAT3 and NF-κB was detected by STAT3 and NF-κB luciferase reporter gene assays.

RESULTS

We found a synergistic effect of TK with CDDP and PXD in primary culture of human NSCLC tumor cells. The combination of CDDP/PXD and TK or CuD inhibited the proliferation of H1299 cells. The combination of CDDP/PXD and TK or CuD induced sub-G1 and G2/M cell cycle arrest in H1299 cells. The combination of CDDP/PXD and TK or CuD induced apoptosis, regulated apoptotic molecules, caused morphological changes and inhibited colony formation in H1299 cells. We found that TK suppresses p-ErbB3 expression and signaling. The combination of CDDP/PXD and TK or CuD inhibited p-AKT, p-Erk, and p-JNK signaling and suppressed Stat3 and NF-κB transcriptional activity in H1299 cells. More importantly, the combination of CDDP/PXD and TK or CuD inhibited p-ErbB3 and downstream molecules in H1299 cells. The combination of CDDP/PXD and TK or CuD inhibited ErbB2/ErbB3 dimerization. Our results clearly demonstrate that the synergistic effect of CDDP/PXD and TK or CuD inhibits cell growth and induces apoptosis by inhibiting ErbB3 signaling.

CONCLUSION

The combination of CDDP/PXD and TK or CuD decreases cell proliferation and induces apoptosis by inhibiting ErbB3 signaling in H1299 lung cancer cells. TK or CuD could be useful as a compound to treat lung cancer. Additionally, targeting ErbB3 may also be useful for treating lung cancer.

Nanomaterials as Inhibitors of Epithelial Mesenchymal Transition in Cancer Treatment

Abstract: Epithelial-mesenchymal transition (EMT) has emerged as a key regulator of cell invasion and metastasis in cancers. Besides the acquisition of migratory/invasive abilities, the EMT process is tightly connected with the generation of cancer stem cells (CSCs), thus contributing to chemoresistance. However, although EMT represents a relevant therapeutic target for cancer treatment, its application in the clinic is still limited due to various reasons, including tumor-stage heterogeneity, molecular-cellular target specificity, and appropriate drug delivery. Concerning this last point, different nanomaterials may be used to counteract EMT induction, providing novel therapeutic tools against many different cancers. In this review, (1) we discuss the application of various nanomaterials for EMT-based therapies in cancer, (2) we summarize the therapeutic relevance of some of the proposed EMT targets, and (3) we review the potential benefits and weaknesses of each approach.

Using high-throughput sequencing to explore the anti-inflammatory effects of α-mangostin

Lipopolysaccharide (LPS) causes an inflammatory response, and α-mangostin (α-MG) is an ingredient of a Chinese herbal medicine with anti-inflammatory effects. We investigated the mechanism by which α-MG reduces LPS-stimulated IEC-6 cells inflammation. A genome-wide examination of control, LPS-stimulated, and α-MG-pretreated cells was performed with the Illumina Hiseq sequencing platform, and gene expression was verified with quantitative real-time PCR (qPCR). Among the 37,199 genes profiled, 2014 genes were regulated in the LPS group, and 475 genes were regulated in the α-MG group. GO enrichment and KEGG pathway analyses of the differentially expressed genes (DEGs) showed that they were mainly related to inflammation and oxidative stress. Based on the transcriptomic results, we constructed a rat model of inflammatory bowel disease (IBD) with LPS and investigated the effects of α-MG on NLRP3 inflammasomes. After LPS stimulation, the rat intestinal villi were significantly detached, with congestion and hemorrhage; the intestinal epithelial cell nuclei were deformed; and the mitochondria were swollen. However, after pretreatment with α-MG, the intestinal villus congestion and hemorrhage were reduced, the epithelial nuclei were rounded, and the mitochondrial morphology was intact. qPCR and western blotting were used to detect NLRP3, caspase 1, interleukin (IL)-18, and IL-1β expression at the gene and protein levels. Their expression increased at both the transcript and protein levels after LPS stimulation, whereas it decreased after pretreatment with α-MG. This study provides new methods and ideas for the treatment of inflammation. α-MG may have utility as a drug for intestinal inflammation.

Identification of α-Mangostin as a Potential Inhibitor of Microtubule Affinity Regulating Kinase 4

Microtubule affinity regulating kinase 4 (MARK4) is a potential drug target for neuronal disorders and several types of cancers. Filtration of naturally occurring compound libraries using high-throughput screening and enzyme assay suggest α-mangostin is a potential inhibitor of MARK4. Structure-based docking and 100 ns molecular dynamics simulation revealed that the binding of α-mangostin stabilizes the MARK4 structure. Enzyme inhibition and binding studies showed that α-mangostin inhibited MARK4 in the submicromolar range with IC₅₀ = 1.47 μM and binding constant (K_a) 5.2 × 10⁷ M^-1. Cell-based studies suggested that α-mangostin inhibited the cell viability (MCF-7 and HepG2), induced apoptosis, arrested the cell cycle in the G0/G1 phase, and reduced tau-phosphorylation. This study implicates MARK4 as a new target of α-mangostin, adding an additional lead molecule to the anticancer repertoire.

The photoactivity of natural products - An overlooked potential of phytomedicines?

BACKGROUND

Photoactivity, though known for centuries, is only recently shifting back into focus as a treatment option against cancer and microbial infections. The external factor light is the ingenious key-component of this therapy: Since light activates the drug locally, a high level of selectivity is reached and side effects are avoided. The first reported photoactive medicines were plant extracts. Synthetic entities (so-called photosensitizers PSs), however, paved the route towards the clinical approval of the so-called photodynamic therapy (PDT), and thus natural PSs took a backseat in the past.

HYPOTHESIS

Many isolated bioactive phytochemicals hold a hidden photoactive potential, which is overlooked due to the reduced common awareness of photoactivity.

METHODS

A systematic review of reported natural PSs and their supposed medicinal application was conducted by employing PubMed, Scifinder, and Web of Science. The identified photoactive natural products were compiled including information about their natural sources, their photoyield, and their pharmacological application. Furthermore, the common chemical scaffolds of natural PS are shown to enable the reader to recognize potentially overlooked natural PSs.

RESULTS

The literature review revealed over 100 natural PS, excluding porphyrins. The PSs were classified according to their scaffold. Thereby it was shown that some PS-scaffolds were analyzed in a detailed way, while other classes were only scarcely investigated, which leaves space for future discoveries. In addition, the literature revealed that many PSs are phytoalexins, thus the selection of the starting material significantly matters in order to find new PSs.

CONCLUSION

Photoactive principles are ubiquitous and can be found in various plant extracts. With the increasing availability of light-irradiation setups for the identification of photoactive natural products, we anticipate the discovery of many new natural PSs in the near future. With the accumulation of chemically diverse PSs, PDT itself might finally reach its clinical breakthrough as a promising alternative treatment against multi-resistant microbes and cancer types.

Potential Anticancer Agents Characterized from Selected Tropical Plants

Higher plants are well known for their value in affording clinically useful anticancer agents, with such compounds acting against cancer cells by a range of mechanisms of action. There remains a strong interest in the discovery and development of plant secondary metabolites as additional cancer chemotherapeutic lead compounds. In the present review, progress on the discovery of plant-derived compounds of the biflavonoid, lignan, sesquiterpene, steroid, and xanthone structural types is presented. Several potential anticancer leads of these types have been characterized from tropical plants collected in three countries as part of our ongoing collaborative multi-institutional project. Preliminary structure-activity relationships and work on in vivo testing and cellular mechanisms of action are also discussed. In addition, the relevant work reported by other groups on the same compound classes is included herein.

Inhibition of pancreatic cancer stem cell characteristics by α-Mangostin: Molecular mechanisms involving Sonic hedgehog and Nanog

The current investigation was intended to elucidate the molecular mechanism of α‐Mangostin in the regulation of pancreatic cancer stem cell (CSC) characteristics. Here, we demonstrate that α‐Mangostin inhibited cell proliferation in pancreatic CSCs and cancer cell lines while it showed no effect on human pancreatic normal ductal epithelial cells. Also, α‐Mangostin inhibited colony formation and induced apoptosis in these cells. Further, α‐Mangostin inhibited the self‐renewal capacity of CSCs isolated from human primary tumours and Kras^G12D mice. Furthermore, α‐Mangostin inhibited the invasive and metastatic ability of pancreatic CSCs by suppressing the epithelial‐to‐mesenchymal transition (EMT) via up‐regulation of E‐cadherin and down‐regulation of mesenchymal phenotype by inhibiting N‐cadherin, Snail and Slug expression. Interestingly, the pluripotency maintaining factors and CSC markers were inhibited by α‐Mangostin thus suggesting that α‐Mangostin can target CSCs to inhibit pancreatic cancer effectively. Gli signalling plays a crucial role in the self‐renewal and pluripotency of CSCs. α‐Mangostin inhibited the Gli transcription and the expression of Gli target genes (Nanog, Oct4, c‐Myc, Sox‐2 and KLF4) in CSCs. Using ChIP assay, we demonstrated that Nanog could directly bind to promoters of Cdk2, Cdk6, FGF4, c‐Myc and α‐Mangostin inhibited Nanog binding to these promoters. Conversely, the inhibitory effects of the α‐Mangostin on CSC proliferation and Gli or Nanog transcription and their targets were abrogated by either enforced activation of sonic hedgehog (Shh) or by the overexpression of Nanog. Taken together, our studies suggest that α‐Mangostin may act as Gli inhibitor and establishes the pre‐clinical significance of α‐Mangostin for the prevention and treatment of pancreatic cancer.

Alpha-mangostin induces apoptosis through activation of reactive oxygen species and ASK1/p38 signaling pathway in cervical cancer cells

Alpha-mangostin, a natural xanthonoid, has been reported to possess the anti-cancer property in various types of human cancer. However, its effects and mechanism of α-mangostin in cervical cancer remain unclear. We found that α-mangostin effectively inhibited cell viability, resulted in loss of mitochondrial membrane potential (MMP), release of cytochrome C, increase of Bax, decrease of Bcl-2, and activation of caspase-9/caspase-3 cascade in cervical cancer cells. Alpha-mangostin elevated the contents of reactive oxygen species (ROS) to activate p38. Disrupting ASK1/p38 signaling pathway by a specific inhibitor of p38, or by the siRNAs against ASK1, MKK3/6, or p38, significantly abolished α-mangostin-induced cell death and apoptotic responses. Moreover, α-mangostin also repressed tumor growth in accordance with increased levels of p-ASK1, p-p38, cleaved-PARP and cleaved-caspase-3 in the tumor mass from the mouse xenograft model of cervical cancer. In the current study, we provided first evidence to demonstrate that dietary antioxidant α-mangostin could inhibit the tumor growth of cervical cancer cells through enhancing ROS amounts to activate ASK1/p38 signaling pathway and damage the integrity of mitochondria and thereby induction of apoptosis in cervical cancer cells.

Bioactivity and pharmacological properties of α-mangostin from the mangosteen fruit: a review

INTRODUCTION

α-Mangostin (α-MG) is the most representative xanthone isolated from the pericarp of mangosteen, possessing extensive biological activities and pharmacological properties, considered as an antineoplastic agent, antioxidant, anti-proliferation and induces apoptosis.

AREAS COVERED

The bioactivity and pharmacological properties of α-MG are being actively investigated by various industrial and academic institutions. The bioactivities of α-MG have been summarized in several previous reviews, which were worthy of high compliment. However, recently, many new literatures about the bioactivities of α-MG have been further reported from 2016 to 2017. Herein, the activities of α-MG are supplemented and summarized in this text.

EXPERT OPINION

As previously said, α-MG possesses good bioactivities pharmacological properties. More recently, it found that α-MG has the effect of maintaining cardiovascular system and gastrointestinal health and controlling free radical oxidation. Furthermore, α-MG has more applications in cosmetics, with the effects of anti-aging, anti-wrinkle, acne treatment, maintenance of skin lubrication. The application of α-MG in treating rheumatoid arthritis has been disclosed and the MG-loaded self-micro emulsion (MG-SME) was designed to improve its pharmacokinetic deficiencies. As mentioned above, α-MG can be a promising drug, also worthy of developing, and further research is crucial for the future application of α-MG.

Cucurbitacin D exhibits its anti-cancer effect in human breast cancer cells by inhibiting Stat3 and Akt signaling

Cucurbitacins are triterpenoids commonly found in Cucurbitaceae and Cruciferae and have long been used in traditional medicine. Cucurbitacins demonstrate anti-inflammatory and anti-cancer activities. We investigated whether cucurbitacin D affects viability in breast cancer cells and its mechanism of action. An MTT assay was used to measure the viability of breast cancer cells. Western blot analysis was used to measure the expression of various modulators, such as p-p53, p-Stat3, p-Akt, and p-NF-κB. Doxorubicin and cucurbitacin D affected the viability of MCF7, MDA-MB-231, and SKBR3 cells. Cucurbitacin D and doxorubicin increased p-p53 expression in MCF7, SKBR3, and MDA-MB-231 cells. Cucurbitacin D suppressed p-Akt, p-NF-κB, and p-Stat3 expression in MCF7, MDA-MB-231, and SKBR3 cells. Doxorubicin alone did not decrease p-Akt and p-Stat3 levels. Cucurbitacin D decreased p-NF-κB and p-Stat3 levels. Doxorubicin in combination with cucurbitacin D increased p-p53 levels and suppressed Akt, NF-κB, Stat3, and Bcl-2 expression more than cucurbitacin D alone. Our results clearly demonstrate that cucurbitacin D could be a useful compound for treating human breast cancer.

Design, synthesis and structure–activity relationships of mangostin analogs as cytotoxic agents

A series xanthone derivatives were synthesized and cytotoxicity results indicated that the isopentene group at C-8 is essential.

α, γ-Mangostins Induce Autophagy and Show Synergistic Effect with Gemcitabine in Pancreatic Cancer Cell Lines

Pancreatic cancer is one of the most lethal and aggressive cancers in the world. However, no effective treatment is currently available for pancreatic cancer. The objective of this study was to determine the anti-pancreatic cancer effect of α-mangostin (αM) and γ-mangostin (γM) extracted from the pericarp of Garcinia mangostana L.. Both αM and γM reduced the viability of pancreatic cancer cells MIA PaCa-2 and PANC-1 in a dose-dependent manner. These compounds induced apoptosis by increasing c-PARP and c-Caspase 3 levels. They also induced autophagy by increasing levels of microtubule-associated protein 1A/1B light chain 3B (LC3II) in both cell lines while decreasing sequestosome 1 (p62) in MIA PaCa-2. Both αM and γM induced autophagy through increasing phosphorylation levels of AMP-activated protein kinase (p-AMPK) and p38-mitogen activated protein kinase (p-p38) while decreasing phosphorylation level of mammalian target of rapamycin complex 1 (p-mTOR). Of various microRNAs (miRNA), miR-18a was found to be a putative regulatory miRNA for autophagy induced by αM or γM. In combination with gemcitabine, a compound frequently used in pancreatic cancer treatment, αM and γM showed synergistic anti-cancer effects in MIA PaCa-2. Collectively, these results suggest that αM and γM can induce apoptosis and autophagy in pancreatic cancer cells and that their anti-cancer effect is likely to be associated with miR-18a. In conclusion, αM and γM might be used as a potential new therapy for pancreatic cancer.

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.

Alpha-Mangostin Reverses Multidrug Resistance by Attenuating the Function of the Multidrug Resistance-Linked ABCG2 Transporter

The ATP-binding cassette (ABC) drug transporter ABCG2 can actively efflux a wide variety of chemotherapeutic agents out of cancer cells and subsequently reduce the intracellular accumulation of these drugs. Therefore, the overexpression of ABCG2 often contributes to the development of multidrug resistance (MDR) in cancer cells, which is one of the major obstacles to successful cancer chemotherapy. Moreover, ABCG2 is highly expressed in various tissues including the intestine and blood-brain barrier (BBB), limiting the absorption and bioavailability of many therapeutic agents. For decades, the task of developing a highly effective synthetic inhibitor of ABCG2 has been hindered mostly by the intrinsic toxicity, the lack of specificity, and complex pharmacokinetics. Alternatively, considering the wide range of diversity and relatively nontoxic nature of natural products, developing potential modulators of ABCG2 from natural sources is particularly valuable. α-Mangostin is a natural xanthone derived from the pericarps of mangosteen (Garcinia mangostana L.) with various pharmacological purposes, including suppressing angiogenesis and inducing cancer cell growth arrest. In this study, we demonstrated that at nontoxic concentrations, α-mangostin effectively and selectively inhibits ABCG2-mediated drug transport and reverses MDR in ABCG2-overexpressing MDR cancer cells. Direct interactions between α-mangostin and the ABCG2 drug-binding site(s) were confirmed by stimulation of ATPase activity and by inhibition of photolabeling of the substrate-binding site(s) of ABCG2 with [¹²⁵I]iodoarylazidoprazosin. In summary, our findings show that α-mangostin has great potential to be further developed into a promising modulator of ABCG2 for reversing MDR and for its use in combination therapy for patients with MDR tumors.

Garcinol and Its Role in Chronic Diseases

The various bioactive compounds isolated from leaves and fruits of Garcinia sps plants, have been characterized and experimentally demonstrated to be anti-oxidant, anti-inflammatory and anti-cancer in nature. Garcinol, a polyisoprenylated benzophenone, obtained from plant Garcinia indica has been found to be an effective inhibitor of several key regulatory pathways (e.g., NF-kB, STAT3 etc.) in cancer cells, thereby being able to control malignant growth of solid tumours in vivo. Despite its high potential as an anti-neoplastic modulator of several cancer types such as head and neck cancer, breast cancer, hepatocellular carcinoma, prostate cancer, colon cancer etc., it is still in preclinical stage due to lack of systematic and conclusive evaluation of pharmacological parameters. While it is promising anti-cancer effects are being positively ascertained for therapeutic development, studies on its effectiveness in ameliorating other chronic diseases such as cardiovascular diseases, diabetes, allergy, neurodegenerative diseases etc., though seem favourable, are very recent and require in depth scientific investigation.

Pharmacology of mangostins and their derivatives: A comprehensive review

Mangosteen (Garcinia mangostana Linn.) is a well-known tropical tree indigenous to Southeast Asia. Its fruit's pericarp abounds with a class of isoprenylated xanthones which are referred as mangostins. Numerous in vitro and in vivo studies have shown that mangostins and their derivatives possess diverse pharmacological activities, such as antibacterial, antifungal, antimalarial, anticarcinogenic, antiatherogenic activities as well as neuroprotective properties in Alzheimer's disease (AD). This review article provides a comprehensive review of the pharmacological activities of mangostins and their derivatives to reveal their promising utilities in the treatment of certain important diseases, mainly focusing on the discussions of the underlying molecular targets/pathways, modes of action, and relevant structure-activity relationships (SARs). Meanwhile, the pharmacokinetics (PK) profile and recent toxicological studies of mangostins are also described for further druggability exploration in the future.

In Vitro and In Vivo Inhibitory Effects of α-Mangostin on Cholangiocarcinoma Cells and Allografts

We investigated the anti-cholangiocarcinoma effect of α-mangostin from Garcinia mangostana pericarp extract (GM) in a human cholangiocarcinoma (CCA) cell line and a hamster CCA allograft model. In vitro, human CCA cells were treated with GM at various concentrations and for different time periods; then cell-cycle arrest and apoptosis were evaluated using flow cytometry, and metastatic potential with wound healing assays. In vivo, hamster allografts were treated with GM, gemcitabine (positive control) and a placebo (negative control) for 1 month; tumor weight and volume were then determined. Histopathological features and immunostaining (CK19 and PCNA) characteristics were examined by microscopy. The present study found that α-mangostin could: inhibit CCA cell proliferation by inducing apoptosis through the mitochondrial pathway; induce G1 cell-cycle arrest; and inhibit metastasis. Moreover, α-mangostin could inhibit CCA growth, i.e. reduce tumor mass (weight and size) and alter CCA pathology, as evidenced by reduced positive staining for CK19 and PCNA. The present study thus suggested that α-mangostin is a promising anti-CCA compound whose ready availability in tropical countries might indicate use for prevention and treatment of CCA.

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.

TRAIL mediated signaling in pancreatic cancer

Research over the years has progressively shown substantial broadening of the tumor necrosis factor alpha- related apoptosis-inducing ligand (TRAIL)-mediated signaling landscape. Increasingly it is being realized that pancreatic cancer is a multifaceted and genomically complex disease. Suppression of tumor suppressors, overexpression of oncogenes, epigenetic silencing, and loss of apoptosis are some of the extensively studied underlying mechanisms. Rapidly accumulating in vitro and in vivo evidence has started to shed light on the resistance mechanisms in pancreatic cancer cells. More interestingly a recent research has opened new horizons of miRNA regulation by DR5 in pancreatic cancer cells. It has been shown that DR5 interacts with the core microprocessor components Drosha and DGCR8, thus impairing processing of primary let-7. Xenografting DR5 silenced pancreatic cancer cells in SCID-mice indicated that there was notable suppression of tumor growth. There is a paradigm shift in our current understanding of TRAIL mediated signaling in pancreatic cancer cells that is now adding new layers of concepts into the existing scientific evidence. In this review we have attempted to provide an overview of recent advances in TRAIL mediated signaling in pancreatic cancer as evidenced byfindings of in vitro and in vivo analyses. Furthermore, we discuss nanotechnological advances with emphasis on PEG-TRAIL and four-arm PEG cross-linked hyaluronic acid (HA) hydrogels to improve availability of TRAIL at target sites.

Cucurbitacin D exhibits potent anti-cancer activity in cervical cancer

In this study, we for the first time, investigated the potential anti-cancer effects of a novel analogue of cucurbitacin (Cucurbitacin D) against cervical cancer in vitro and in vivo. Cucurbitacin D inhibited viability and growth of cervical cancer cells (CaSki and SiHa) in a dose-dependent manner. IC50 of Cucurbitacin D was recorded at 400 nM and 250 nM in CaSki and SiHa cells, respectively. Induction of apoptosis was observed in Cucurbitacin D treated cervical cancer cells as measured by enhanced Annexin V staining and cleavage in PARP protein. Cucurbitacin D treatment of cervical cancer cells arrested the cell cycle in G1/S phase, inhibited constitutive expression of E6, Cyclin D1, CDK4, pRb, and Rb and induced the protein levels of p21 and p27. Cucurbitacin D also inhibited phosphorylation of STAT3 at Ser727 and Tyr705 residues as well as its downstream target genes c-Myc, and MMP9. Cucurbitacin D enhanced the expression of tumor suppressor microRNAs (miR-145, miRNA-143, and miRNA34a) in cervical cancer cells. Cucurbitacin D treatment (1 mg/kg body weight) effectively inhibited growth of cervical cancer cells derived orthotopic xenograft tumors in athymic nude mice. These results demonstrate the potential therapeutic efficacy of Cucurbitacin D against cervical cancer.

α-Mangostin-encapsulated PLGA nanoparticles inhibit pancreatic carcinogenesis by targeting cancer stem cells in human, and transgenic (Kras(G12D), and Kras(G12D)/tp53R270H) mice

Activation of sonic hedgehog (Shh) in cancer stem cell (CSC) has been demonstrated with aggressiveness of pancreatic cancer. In order to enhance the biological activity of α-mangostin, we formulated mangostin-encapsulated PLGA nanoparticles (Mang-NPs) and examined the molecular mechanisms by which they inhibit human and KC mice (Pdx^Cre;LSL-Kras^G12D) pancreatic CSC characteristics in vitro, and pancreatic carcinogenesis in KPC (Pdx^Cre;LSLKras^G12D;LSL-Trp53^R172H) mice. Mang-NPs inhibited human and Kras^G12D mice pancreatic CSC characteristics in vitro. Mang-NPs also inhibited EMT by up-regulating E-cadherin and inhibiting N-cadherin and transcription factors Slug, and pluripotency maintaining factors Nanog, c-Myc, and Oct4. Furthermore, Mang-NPs inhibited the components of Shh pathway and Gli targets. In vivo, Mang-NPs inhibited the progression of pancreatic intraneoplasia to pancreatic ductal adenocarcinoma and liver metastasis in KPC mice. The inhibitory effects of Mang-NPs on carcinogenesis in KPC mice were associated with downregulation of pluripotency maintaining factors (c-Myc, Nanog and Oct4), stem cell markers (CD24 and CD133), components of Shh pathway (Gli1, Gli2, Patched1/2, and Smoothened), Gli targets (Bcl-2, XIAP and Cyclin D1), and EMT markers and transcription factors (N-cadherin, Slug, Snail and Zeb1), and upregulation of E-cadherin. Overall, our data suggest that Mang-NPs can inhibit pancreatic cancer growth, development and metastasis by targeting Shh pathway.