Galangin inhibits proliferation of HepG2 cells by activating AMPK via increasing the AMP/TAN ratio in a LKB1-independent manner

Targeting the mTOR Pathway in Hepatocellular Carcinoma: The Therapeutic Potential of Natural Products

Despite advancements in cancer treatment through surgery and drugs, hepatocellular carcinoma (HCC) remains a significant challenge, as reflected by its low survival rates. The mammalian target of rapamycin (mTOR) signaling pathway plays a crucial role in regulating the cell cycle, proliferation, apoptosis, and metabolism. Notably, dysregulation leading to the activation of the mTOR signaling pathway is common in HCC, making it a key focus for in-depth research and a target for current therapeutic strategies. This review focuses on the role of the mTOR signaling pathway and its downstream effectors in regulating HCC cell proliferation, apoptosis, autophagy, cell cycle, and metabolic reprogramming. Moreover, it emphasizes the potential of natural products as modulators of the mTOR signaling pathway. When incorporated into combination therapies, these natural products have been demonstrated to augment therapeutic efficacy and surmount drug resistance. These products target key signaling pathways such as mTOR signaling pathways. Examples include 11-epi-sinulariolide acetate, matrine, and asparagus polysaccharide. Their inhibitory effects on these processes suggest valuable directions for the development of more effective HCC therapeutic strategies. Various natural products have demonstrated the ability to inhibit mTOR signaling pathway and suppress HCC progression. These phytochemicals, functioning as mTOR signaling pathway inhibitors, hold great promise as potential anti-HCC agents, especially in the context of overcoming chemoresistance and enhancing the outcomes of combination therapies.

Small-molecule agents for treating skin diseases

Skin diseases are a class of common and frequently occurring diseases that significantly impact daily lives. Currently, the limited effective therapeutic drugs are far from meeting the clinical needs; most drugs typically only provide symptomatic relief rather than a cure. Developing small-molecule drugs with improved efficacy holds paramount importance for treating skin diseases. This review aimed to systematically introduce the pathogenesis of common skin diseases in daily life, list related drugs applied in the clinic, and summarize the clinical research status of candidate drugs and the latest research progress of candidate compounds in the drug discovery stage. Also, it statistically analyzed the number of publications and global attention trends for the involved skin diseases. This review might provide practical information for researchers engaged in dermatological drugs and further increase research attention to this disease area.

Galangin: A food-derived flavonoid with therapeutic potential against a wide spectrum of diseases

Galangin is an important flavonoid with natural activity, that is abundant in galangal and propolis. Currently, various biological activities of galangin have been disclosed, including anti-inflammation, antibacterial effect, anti-oxidative stress and aging, anti-fibrosis, and antihypertensive effect. Based on the above bioactivities, more and more attention has been paid to the role of galangin in neurodegenerative diseases, rheumatoid arthritis, osteoarthritis, osteoporosis, skin diseases, and cancer. In this paper, the natural sources, pharmacokinetics, bioactivities, and therapeutic potential of galangin against various diseases were systematically reviewed by collecting and summarizing relevant literature. In addition, the molecular mechanism and new preparation of galangin in the treatment of related diseases are also discussed, to broaden the application prospect and provide reference for its clinical application. Furthermore, it should be noted that current toxicity and clinical studies of galangin are insufficient, and more evidence is needed to support its possibility as a functional food.

Pharmacological activities and therapeutic potential of galangin, a promising natural flavone, in age-related diseases

BACKGROUND

The extension of average life expectancy and the aggravation of population aging have become the inevitable trend of human development. In an aging society, various problems related to medical care for the elderly have become increasingly prominent. However, most of the age-related diseases have the characteristics of multiple diseases at the same time, prone to complications, and atypical clinical manifestations, which bring great difficulties to its treatment. Galangin (3,5,7-trihydroxyflavone) is a natural active compound extracted from the root of Alpinia officinarum Hance (Zingiberaceae). Recently, many studies have shown that galangin has potential advantages in the treatment of neurodegenerative diseases and cardiovascular and cerebrovascular diseases, which are common in the elderly. In addition, it also showed that galangin had prospective activities in the treatment of tumor, diabetes, liver injury, asthma and arthritis.

PURPOSE

This review aims to systematically summarize and discuss the effects and the underlying mechanism of galangin in the treatment of age-related diseases.

METHODS

We searched PubMed, SciFinder, Web of Science and CNKI literature database resources, combined with the keywords "galangin", "neurodegenerative disease", "tumor", "diabetes", "pharmacological activity", "drug combination", "pharmacokinetics", "drug delivery system" and "safety", and comprehensively reviewed the pharmacological activities and mechanism of galangin in treating age-related diseases.

RESULTS

According to the previous studies on galangin, the anti-neurodegenerative activity, cardiovascular and cerebrovascular protective activity, anti-tumor activity, anti-diabetes activity, anti-arthritis activity, hepatoprotective activity and antiasthmatic activity of galangin were discussed, and the related mechanisms were classified and summarized in detail. In addition, the drug combination, pharmacokinetics, drug delivery system and safety of galangin were furtherly discussed.

CONCLUSIONS

This review will provide reference for galangin in the treatment of age-related diseases. Meanwhile, further experimental research and long-term clinical trials are needed to determine the therapeutic safety and efficacy of galangin.

3,5,7-trihydroxyflavone restricts proliferation of androgen-independent human prostate adenocarcinoma cells by inducing ROS-mediated apoptosis and reduces tumour growth

Flavonoids are among the largest groups of secondary metabolites. Studies suggest that dietary intake of flavonoids reduces the risk of cancer. 3,5,7-trihydroxyflavone (THF) belongs to the flavone class of flavonoids and potentially inhibits the growth of many cancers; however, it is unexplored in prostate cancer. This study reports the antiproliferative potential of THF in prostate cancer cell line via reactive oxygen species (ROS)-mediated cascades and examines the tumour reduction potential in swiss albino mice. The potency of THF was evaluated by employing cytotoxicity assays and wound healing assays. Cell cycle, ROS, mitochondrial membrane potential (MMP), and Annexin-V-FITC assay were performed using a flow cytometer. In vivo, anticancer potential was achieved using the mice Ehrlich Ascites Carcinoma (EAC) model. THF inhibits cell growth with IC50 of 64.30 µM (MTT), 81.22 µM (NRU) and 25.81 µM (SRB), substantiated by cell migration assay. Cell-cycle analysis revealed that THF increases the subdiploid population. Furthermore, the Annexin-V-FITC assay evoked a significant induction of late apoptosis at a higher concentration of THF. THF also disrupts MMP, caused by an increased generation of ROS. In the EAC model, THF significantly inhibits tumour growth and increases the percent survival of mice and ROS levels in EAC cells. Hence, it may be concluded that THF might execute its antiproliferative effect via inducing ROS generation and could be a promising lead for preclinical and clinical validations.

Galangin delivered by retinoic acid-modified nanoparticles targeted hepatic stellate cells for the treatment of hepatic fibrosis

Hepatic fibrosis (HF) is a chronic hepatic pathological process induced by various liver injuries, with few available therapies. Previous research studies revealed that HF is characterized by the accumulation of excess extracellular matrix in the liver, mainly overexpressed by activated hepatic stellate cells (HSC). Therefore, HSC have been targeted in clinical trials for the management of HF. The aim of the present study was to develop an anti-HF drug delivery system with acrylic resin (Eudragit® RS100, Eud RS100) nanoparticles (NPs) through modification by retinoic acid (RA), modified for binding the retinol-binding protein reporter (RBPR) in HSC. Galangin (GA), is a multiple effects flavonoid which has demonstrated an anti-HF effect in our previous studies. In this study, GA was utilized for the treatment of HF. The results revealed that the NPs were well formed (diameter: 70 nm), spherical in shape, and exhibited uniform distribution and a high encapsulation efficiency. Moreover, a prominent controlled release effect and a significant increase in bioavailability was observed following the encapsulation of GA in NPs. These findings indicated that the limitation of low bioavailability due to the hydrophobic feature of GA was overcome. Furthermore, the pharmacodynamics studies demonstrated that NPs could drastically influence the anti-HF effects of GA after modification with retinoic acid. The results of the present study suggested that retinoic acid-modified GA NPs represent a promising candidate in the development of an anti-HF drug delivery system for the treatment of HF.

Crosstalk between xanthine oxidase (XO) inhibiting and cancer chemotherapeutic properties of comestible flavonoids- a comprehensive update

Gout is an inflammatory disease caused by metabolic disorder or genetic inheritance. People throughout the world are strongly dependent on ethnomedicine for the treatment of gout and some receive satisfactory curative treatment. The natural remedies as well as established drugs derived from natural sources or synthetically made exert their action by mechanisms that are closely associated with anticancer treatment mechanisms regarding inhibition of xanthine oxidase, feedback inhibition of de novo purine synthesis, depolymerization and disappearance of microtubule, inhibition of NF-ĸB activation, induction of TRAIL, promotion of apoptosis, and caspase activation and proteasome inhibition. Some anti-gout and anticancer novel compounds interact with same receptors for their action, e.g., colchicine and colchicine analogues. Dietary flavonoids, i.e., chrysin, kaempferol, quercetin, fisetin, pelargonidin, apigenin, luteolin, myricetin, isorhamnetin, phloretinetc etc. have comparable IC₅₀ values with established anti-gout drug and effective against both cancer and gout. Moreover, a noticeable number of newer anticancer compounds have already been isolated from plants that have been using by local traditional healers and herbal practitioners to treat gout. Therefore, the anti-gout plants might have greater potentiality to become selective candidates for screening of newer anticancer leads.

Galangin Exhibits Neuroprotective Effects in 6-OHDA-Induced Models of Parkinson’s Disease via the Nrf2/Keap1 Pathway

Parkinson’s disease (PD) is the second most common neurodegenerative disease, and there is still no cure for it. PD is characterized by the degeneration of dopaminergic neurons, and oxidative stress has been considered an important pathological mechanism. Therefore, the discovery of antioxidants to alleviate the oxidative damage of dopaminergic neurons is a promising therapeutic strategy for PD. First, a network pharmacology approach was used, and nine common core targets of galangin and PD were screened, mainly involving cell aging, apoptosis, and cellular responses to hydrogen peroxide and hypoxia. In addition, the Gene Ontology (GO) function and pathway enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) identified apoptosis, PI3K/Akt, and HIF-1 signaling pathways. Furthermore, the molecular docking results revealed a strong affinity between galangin and the NFE2L2/Nrf2 protein. To validate the above predictions, we employed 6-hydroxydopamine (6-OHDA) to induce neuronal death in HT22 cells and Caenorhabditis elegans (C. elegans). MTT, cell morphology observation, and Hoechst 33342-PI staining results showed that galangin significantly increased the viability of 6-OHDA-treated HT22 cells. In addition, galangin inhibited 6-OHDA-induced ROS generation and apoptosis in HT22 cells. Mechanistic studies demonstrated that galangin activates the Nrf2/Keap1 signaling pathway, as evidenced by the decreased protein expression of Keap1 and increased protein expression of Nrf2 and HO-1. In the 6-OHDA-induced PD model of C. elegans, galangin indeed inhibited the degeneration of dopaminergic neurons, improved behavioral ability, and decreased ROS generation. In conclusion, the current study is the first to show that galangin has the capacity to inhibit neuronal degeneration via the Nrf2/Keap1 pathway, suggesting that galangin is a possible PD treatment.

Galangin inhibits neointima formation induced by vascular injury via regulating the PI3K/AKT/mTOR pathway

Galangin inhibits neointimal hyperplasia after vascular injury by inhibiting vascular smooth muscle cell proliferation, migration, phenotypic switching and promoting autophagy.

Galangin: A metabolite that suppresses anti-neoplastic activities through modulation of oncogenic targets

With the dramatic increase in cancer incidence all over the world in the last decades, studies on identifying novel efficient anti-cancer agents have been intensified. Historically, natural products have represented one of the most important sources of new lead compounds with a wide range of biological activities. In this article, the multifaceted anti-cancer action of propolis-derived flavonoid, galangin, is presented, discussing its antioxidant, anti-inflammatory, antiproliferative, pro-apoptotic, anti-angiogenic, and anti-metastatic effects in various cancer cells. In addition, co-effects with standard chemotherapeutic drugs as well as other natural compounds are also under discussion, besides highlighting modern nanotechnological advancements for overcoming the low bioavailability issue characteristic of galangin. Although further studies are needed for confirming the anti-cancer potential of galangin in vivo malignant systems, exploring this natural compound might open new perspectives in molecular oncology.

The antitumour effect of galangin and luteolin with doxorubicin on chemically induced hepatocellular carcinoma in rats

Hepatocellular carcinoma (HCC), a highly malignant tumour with very high morbidity and mortality, remains the second cause of cancer-related deaths worldwide. Galangin is a naturally occurring flavonoid extracted from the propolis and root of Alpinia officinarum, which possesses antitumour efficacy, which has resulted in an increase in interest in related research. Additionally, galangin inhibits cell proliferation and induces apoptosis in several human malignancies. On the other hand, luteolin, a naturally occurring flavonoid found in a variety of edible plants, augments cytotoxicity in different cancer cells through the inhibition of cell-survival pathways and activation of apoptosis. Moreover, luteolin blocks the activity of anti-apoptotic Bcl-2 family members. The present study aimed to assess the antitumour effect of galangin and luteolin in combination and the antitumour effect of a combination of galangin and luteolin together with doxorubicin (DOX) in a chemically induced HCC rat model. Our analyses demonstrated that the combination treatment with galangin, luteolin, and DOX showed the greatest antineoplastic activity against HCC, which was observed by significant decreases in the levels of HCC markers, including serum α-fetoprotein-L3, and hepatic tissue expression of both glypican 3 and heat shock proteins. On the other hand, the hepatic tissue expression of caspase-3 was significantly increased. These results suggest that combination treatment with galangin and luteolin is a promising candidate for clinical use in HCC chemotherapy, especially when used in combination with DOX.

Cogent role of flavonoids as key orchestrators of chemoprevention of hepatocellular carcinoma: A review

Chemopreventive approaches with food-derived phytochemicals are progressively rising as a significant aspect of tumor management and control. Herein, we have showcased the major phytoconstituents belonging to the group of flavanoid, as anti-cancer agents used for the treatment and prevention of hepatocellular carcinoma (HCC). Sorafenib is the sole drug used for the treatment of advanced HCC, but its clinical application is limited because of its severe adverse effects and drug resistance. Diet-based chemoprevention seems to be the way forward for this disease of malignant nature. As HCC is derived from a chronic inflammatory milieu, the regular incorporation of bioactive phytochemicals in the diet will confer protection and prevent progression to hepatocarcinogenesis. Many preclinical studies proved that the health benefits of flavonoids confer cytotoxic potential against various types of cancers including hepatocellular carcinoma. As flavonoids with excellent safety profile are abundantly present in common vegetables and fruits, they can be better utilized for chemoprevention and chemosensitization in such chronic condition. This review highlights the plausible role of the eight most promising flavonoids (Curcumin, Kaempferol, Resveratrol, Quercetin, Silibinin, Baicalein, Galangin and Luteolin) as key orchestrators of chemoprevention in hepatocellular carcinoma with preclinical and clinical evidence. An attempt to address the challenges in its clinical translation is also included. This review also provides an insight into the close association of HCC and metabolic disorders which may further decipher the chemopreventive effect of dietary bioactive from a proof of concept to extensive clinical translation. PRACTICAL APPLICATIONS: According to GLOBOCAN 2020 database, it is estimated that 905,677 new cases of liver cancer and approximately 830,180 deaths related to that. The cancer incidence and mortality are almost similar as it is diagnosed at an advanced stage in patients where systemic drug therapy is the sole approach. Due to the emergence of multidrug resistance and drug-related toxicities, most of the patient can not adhere to the therapy regimen. Flavonoids are known to be a potential anticancer agent with an excellent safety profile. These are found to be effective preclinically against hepatocellular carcinoma through modulation of numerous pathways in hepatocarcinogenesis. But, the bioavailability issue, lack of well designed-validated clinical evidence, the possibility of food-drug interaction etc limit its clinical utility. The research inputs mainly to overcome pharmacokinetic issues along with suitable validation of efficacy and toxicity will be a critical point for establishing flavonoids as an effective, safe, affordable therapeutics.

A comprehensive review on chemotherapeutic potential of galangin

Galangin, a non-toxic phytochemical is known to possess several therapeutic applications. Mounting evidences have demonstrated that galangin a naturally available flavonoid exerts anticancer effects via several mechanisms. The phytocompound induces apoptosis and renders antiangiogenic property. Additionally, galangin has demonstrated significate results in combating various cancer types when administered in combination with other phytocompounds or with gold nanoparticles (GNPs). The present article is a critical review of galangin for its treatment on different types of cancer and its usability as an alternative cancer therapeutics.

Simultaneous determination of two galangin metabolites from Alpinia Officinarum Hance in rat plasma by UF LC-MS/MS and its application in pharmacokinetics study

Galangin has multiple pharmacological efficacies, such as anti-cancer, anti-inflammation and anti-oxidation. Galangin can be rapidly converted into glucuronidated metabolites in vivo. This study aimed to establish an UFLC-MS/MS analytical method to simultaneously determine the concentrations of two glucuronidated metabolites of galangin, galangin-3-O-β-D-glucuronic acid (GG-1) and galangin-7-O-β-D-glucuronic acid (GG-2) in rat plasma. After oral administration of galangal extract (0.3 g/kg), blood samples were collected from the orbital sinus, then treated by methanol precipitation and further gradient-eluted with Phenomenex Kinetex 2.6 µm XB-C18 column. The mass spectrometer was manipulated in the negative electrospray ionization (ESI) and selected multiple reaction monitoring (MRM) mode for the analytes. The precursor-to-product ion pairs applied for GG-1, GG-2 and chrysin (as the internal standard, IS) were m/z 445.2→269.0, 445.2→268.9 and 253.0→142.9, respectively. The results showed that the linear ranges for both GG-1 and GG-2 were 2.0–2000.0 ng/mL (r² > 0.995). The inter- and intra-day precision were 89.3%–109.2%, RSD was less than 15%, and the repeatability was good. The recoveries of both metabolites and IS were over 89%, and matrix effect was within 15%. The validated analytical method was further applied to study the pharmacokinetic profiles of GG-1 and GG-2 in vivo. The pharmacokinetic parameters suggested that T_max of GG-1 was equivalent to that of GG-2, and MRT_0-t, t_1/2 of GG-2 were a little higher than those of GG-1. Importantly, AUC_0-t and C_max of GG-2 were almost twice as those of GG-1. In short, the validated UFLCMS/MS analytical method was feasible to simultaneously determine two galangin metabolites GG-1 and GG-2 in rat plasma and further analyze in vivo metabolism of galangin.

Autophagy: Mechanisms and Therapeutic Potential of Flavonoids in Cancer

Autophagy, which is a conserved biological process and essential mechanism in maintaining homeostasis and metabolic balance, enables cells to degrade cytoplasmic constituents through lysosomes, recycle nutrients, and survive during starvation. Autophagy exerts an anticarcinogenic role in normal cells and inhibits the malignant transformation of cells. On the other hand, aberrations in autophagy are involved in gene derangements, cell metabolism, the process of tumor immune surveillance, invasion and metastasis, and tumor drug-resistance. Therefore, autophagy-targeted drugs may function as anti-tumor agents. Accumulating evidence suggests that flavonoids have anticarcinogenic properties, including those relating to cellular proliferation inhibition, the induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, the impairment of cell migration, invasion, tumor angiogenesis, and the reduction of multidrug resistance in tumor cells. Flavonoids, which are a group of natural polyphenolic compounds characterized by multiple targets that participate in multiple pathways, have been widely studied in different models for autophagy modulation. However, flavonoid-induced autophagy commonly interacts with other mechanisms, comprehensively influencing the anticancer effect. Accordingly, targeted autophagy may become the core mechanism of flavonoids in the treatment of tumors. This paper reviews the flavonoid-induced autophagy of tumor cells and their interaction with other mechanisms, so as to provide a comprehensive and in-depth account on how flavonoids exert tumor-suppressive effects through autophagy.

Recent Advances in Characterizing Natural Products that Regulate Autophagy

Autophagy, an intricate response to nutrient deprivation, pathogen infection, Endoplasmic Reticulum (ER)-stress and drugs, is crucial for the homeostatic maintenance in living cells. This highly regulated, multistep process has been involved in several diseases including cardiovascular and neurodegenerative diseases, especially in cancer. It can function as either a promoter or a suppressor in cancer, which underlines the potential utility as a therapeutic target. In recent years, increasing evidence has suggested that many natural products could modulate autophagy through diverse signaling pathways, either inducing or inhibiting. In this review, we briefly introduce autophagy and systematically describe several classes of natural products that implicated autophagy modulation. These compounds are of great interest for their potential activity against many types of cancer, such as ovarian, breast, cervical, pancreatic, and so on, hoping to provide valuable information for the development of cancer treatments based on autophagy.

Galangin Reverses Hepatic Fibrosis by Inducing HSCs Apoptosis via the PI3K/Akt, Bax/Bcl-2, and Wnt/β-Catenin Pathway in LX-2 Cells

Hepatic fibrosis (HF) is a common disease, with currently no available treatment. Galangin, a natural flavonoid extracted from Alpinia officinaruim Hance, has multiple effects demonstrated in previous studies. The aim of the present study was to explore the anti-fibrogenic effect of galangin in vitro, and research its potential molecular mechanisms. LX-2 cells were chosen as an in vitro HF model, and were treated with galangin in different concentrations. Cell viability was analyzed using Cell Counting Kit-8 (CCK-8) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell apoptosis was measured using flow cytometry, and the anti-fibrogenic effect of galangin was determined using RT-quantitative (q)PCR, immunofluorescence, and Western blotting. The results show that the proliferation of LX-2 cells was efficiently inhibited by galangin, and apoptosis was induced in a dose-dependent manner. Both the mRNA and protein expression of alpha-smooth muscle actin (α-SMA) and collagen I were markedly downregulated. Galangin also inhibited the phosphatidylinositol 3-kinase (PI3K)/Akt and Wnt/β-catenin signaling pathways and increased the Bax/Bcl-2 ratio. The results of this study suggest that galangin has an anti-fibrogenic effect and may represent a promising agent in the treatment of hepatic fibrosis.

The Natural Flavonoid Galangin Elicits Apoptosis, Pyroptosis, and Autophagy in Glioblastoma

Galangin (GG), a flavonoid, elicits a potent antitumor activity in diverse cancers. Here, we evaluated the efficacy of GG in the treatment of human glioblastoma multiforme (GBM) and investigated the molecular basis for its inhibitory effects in the disease. GG inhibited viability and proliferation of GBM cells (U251, U87MG, and A172) in a dose-dependent manner (IC₅₀ = 221.8, 262.5, 273.9 μM, respectively; P < 0.001; EdU, ~40% decrease at 150 μM, P < 0.001), and the number of colonies formed was significantly reduced (at 50 μM, P < 0.001). However, normal human astrocytes were more resistant to its cytotoxic effects (IC₅₀ >450 μM). Annexin-V/PI staining was increased indicating that GG induced apoptosis in GBM cells (26.67 and 30.42%, U87MG and U251, respectively) and associated proteins including BAX and cleaved PARP-1 were increased (~3×). Cells also underwent pyroptosis as determined under phase-contrast microscopy. Knockdown of gasdermin E (GSDME), a protein involved in pyroptosis, alleviated pyroptosis induced by GG through aggravating nuclear DNA damage in GBM cells. Meanwhile, fluorescent GFP-RFP-MAP1LC3B puncta associated with autophagy increased under GG treatment, and transmission electron microscopy confirmed the formation of autophagic vesicles. Inhibition of autophagy enhanced GG-induced apoptosis and pyroptosis in GBM cells. Finally, in an orthotopic xenograft model in nude mice derived from U87MG cells, treatment with GG in combination with an inhibitor of autophagy, chloroquine, suppressed tumor growth, and enhanced survival compared to GG monotherapy (P < 0.05). Our results demonstrated that GG simultaneously induces apoptosis, pytoptosis, and protective autophagy in GBM cells, indicating that combination treatment of GG with autophagy inhibitors may be an effective therapeutic strategy for GBM.

Synthesis, characterization, and photodynamic therapy activity of 5,10,15,20-Tetrakis(carboxyl)porphyrin

Water-soluble porphyrins are considered promising drug candidates for photodynamic therapy (PDT). This study investigated the PDT activity of a new water-soluble, anionic porphyrin (1-Zn), which possesses four negative charges. The photodynamic anticancer activity of 1-Zn was investigated by the MTT assay, with mTHPC as a positive control. The cellular distribution was determined by fluorescence microscopy. Holographic and phase contrast images were recorded after 1-Zn treatment with a HoloMonitor™ M3 instrument. The inhibition of A549 cell growth achieved by inducing apoptosis was investigated by flow cytometry and fluorescence microscopy. DNA damage was investigated by the comet assay. The expression of apoptosis-related proteins was also measured by western blot assays. 1-Zn had better phototoxicity against A549 cells than HeLa and HepG2 cancer cells. Interestingly, 1-Zn was clearly located almost entirely in the cell cytoplasmic region/organelles. The late apoptotic population was less than 1.0% at baseline in the untreated and only light-treated cells and increased to 40.5% after 1-Zn treatment and irradiation (P < 0.05). 1-Zn triggered significant ROS generation after irradiation, causing ΔΨm disruption (P < 0.01) and DNA damage. 1-Zn induced A549 cell apoptosis via the mitochondrial apoptosis pathway. In addition, 1-Zn bound in the groove of DNA via an outside binding mode by pi-pi stacking and hydrogen bonding. 1-Zn exhibits good photonuclease activity and might serve as a potential photosensitizer (PS) for lung cancer cells.

Galangin Inhibits Thrombin-Induced MMP-9 Expression in SK-N-SH Cells via Protein Kinase-Dependent NF-κB Phosphorylation

Galangin, a member of the flavonol compounds of the flavonoids, could exert anti-inflammatory effects in various cell types. It has been used for the treatment of arthritis, airway inflammation, stroke, and cognitive impairment. Thrombin, one of the regulators of matrix metalloproteinase (MMPs), has been known as a vital factor of physiological and pathological processes, including cell migration, the blood–brain barrier breakdown, brain edema formation, neuroinflammation, and neuronal death. MMP-9 especially may contribute to neurodegenerative diseases. However, the effect of galangin in combating thrombin-induced MMP-9 expression is not well understood in neurons. Therefore, we attempted to explore the molecular mechanisms by which galangin inhibited MMP-9 expression and cell migration induced by thrombin in SK-N-SH cells (a human neuroblastoma cell line). Gelatin zymography, western blot, real-time PCR, and cell migration assay were used to elucidate the inhibitory effects of galangin on the thrmbin-mediated responses. The results showed that galangin markedly attenuated the thrombin-stimulated phosphorylation of proto-oncogene tyrosine-protein kinase (c-Src), proline-rich tyrosine kinase 2 (Pyk2), protein kinase C (PKC)α/β/δ, protein kinase B (Akt), mammalian target of rapamycin (mTOR), p42/p44 mitogen-activated protein kinase (MAPK), Jun amino-terminal kinases (JNK)1/2, p38 MAPK, forkhead box protein O1 (FoxO1), p65, and c-Jun and suppressed MMP-9 expression and cell migration in SK-N-SH cells. Our results concluded that galangin blocked the thrombin-induced MMP-9 expression in SK-N-SH cells via inhibiting c-Src, Pyk2, PKCα/βII/δ, Akt, mTOR, p42/p44 MAPK, JNK1/2, p38 MAPK, FoxO1, c-Jun, and p65 phosphorylation and ultimately attenuated cell migration. Therefore, galangin may be a potential candidate for the management of brain inflammatory diseases.

Rapamycin enhances growth inhibition on urothelial carcinoma cells through LKB1 deficiency-mediated mitochondrial dysregulation

Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, has significant potential for application in the treatment of urothelial carcinoma (URCa) of the bladder. Previous studies have shown that regulation of the AMP-activated serine/threonine protein kinase (AMPK)-mTOR signaling pathway enhances apoptosis by inducing autophagy or mitophagy in bladder cancer. Alteration of liver kinase B1 (LKB1)-AMPK signaling leads to mitochondrial dysfunction and the accumulation of autophagy-related proteins as a result of mitophagy, resulting in enhanced cell sensitivity to drug treatments. Therefore, we hypothesized that LKB1 deficiency in URCa cells could lead to increased sensitivity to rapamycin by inducing mitochondrial defect-mediated mitophagy. To test this, we established stable LKBI-knockdown URCa cells and analyzed the effects of rapamycin on their growth. Rapamycin enhanced growth inhibition and apoptosis in stable LKB1-knockdown URCa cells and in a xenograft mouse model. In spite of the stable downregulation of LKB1 expression, rapamycin induced AMPK activation in URCa cells, causing loss of the mitochondrial membrane potential, ATP depletion, and ROS accumulation, indicating an alteration of mitochondrial biogenesis. Our findings suggest that the absence of LKB1 can be targeted to induce dysregulated mitochondrial biogenesis by rapamycin treatment in the design of novel therapeutic strategies for bladder cancer.

Sodium butyrate induces autophagy in colorectal cancer cells through LKB1/AMPK signaling

Butyrate is produced by the fermentation of undigested dietary fibers and acts as the promising candidate for cancer treatment. However, the mechanism underlying sodium butyrate (NaB)-induced autophagy in colorectal cancer is not yet completely understood. The expressions of LC3-II protein and mRNA were detected by western blot and quantitative RT-PCR in colorectal cancer (CRC) cell lines HCT-116 and HT-29, respectively. Autolysosome formation was observed by transmission electron microscope. AMPK and LKB1 were inhibited by chemical inhibitor or siRNAs and confirmed by western blot. NaB elevated the protein and mRNA expressions of LC3 in a dose-dependent manner. NaB treatment increased the formation of autolysosome and expression of phosphorylated liver kinase B1 (LKB1), AMP-activated protein kinase (AMPK), and acetyl-CoA carboxylase (ACC). Treatment with compound C (an inhibitor of AMPK) and siRNA-mediated knockdown of AMPK and LKB1 significantly attenuated NaB-induced autophagy in CRC cells. Collectively, these findings indicated that LKB1 and AMPK are critical for NaB-mediated autophagy and may act as the novel targets for colorectal cancer therapy in the future.

A review on the ethnomedicinal uses, phytochemistry and pharmacology of Alpinia officinarum Hance

ETHNOPHARMACOLOGICAL RELEVANCE

Alpinia officinarum Hance is a perennial plant that has been traditionally used for many decades to treat several ailments including inflammation, pain, stomach-ache, cold, amongst others. Pharmacological studies over the years have demonstrated remarkable bioactivities that could be further explored for development of new therapeutic agents against various ailments.

AIM OF THE STUDY

The paper critically reviewed the ethno-medicinal uses, pharmacology, and phytochemistry of A. officinarum.

METHODS

Keywords including A. officinarum and its synonyms were searched using electronic databases including ISI web of knowledge, Science direct, Scopus, PubMed, Google scholar and relevant database for Masters and Doctoral theses.

RESULTS

A. officinarum is prepared in Asia, Turkey, Morocco and Iran as a decoction, infusion or juice as a single preparation or in combination with other herbs, food or drinks for the treatment of general health problems including cold, inflammation, digestive disorders, etc. Pharmacological studies revealed the potent in vitro and in vivo bioactivities of various parts of A. officinarum that include anti-inflammatory, cytotoxicity, homeostasis, lipid regulation, antioxidant, antiviral, antimicrobial, antiosteoporosis, etc. Over 90 phytochemical constituents have been identified and isolated from A. officinarum comprising vastly of phenolic compounds especially diarylheptanoids isolated from the rhizome and considered the most active bioactive components.

CONCLUSION

In vitro and in vivo studies have confirmed the potency of A. officinarum. However, further studies are required to establish the mechanisms mediating its bioactivities in relation to the medicinal uses as well as investigating any potential toxicity for future clinical studies.

Galangin Induces Apoptosis in MCF-7 Human Breast Cancer Cells Through Mitochondrial Pathway and Phosphatidylinositol 3-Kinase/Akt Inhibition

AIMS

The study aimed to investigate the molecular mechanism of inhibition of proliferation and apoptosis induction by galangin against MCF-7 human breast cancer cells.

METHODS

Cell Counting Kit-8 assay was used to assess cell viability and flow cytometry was used to detect cell apoptosis. The expression level of apoptosis-related proteins (cleaved-caspase-9, cleaved-caspase-8, cleaved-caspase-3, Bad, cleaved-Bid, Bcl-2, Bax, p-phosphatidylinositol 3-kinase [PI3K], and p-Akt) and cell cycle-related proteins (cyclin D3, cyclin B1, cyclin-dependent kinases CDK1, CDK2, CDK4, p21, p27, p53) were evaluated by Western blotting.

RESULTS

Galangin increased the expression of Bax and decreased the expression of Bcl-2 in a concentration-dependent manner, inhibited cell viability, and induced apoptosis. Meanwhile, the expression of cleavage of caspase-9, caspase-8, caspase-3, Bid, and Bad increased significantly while the expression of p-PI3K and p-Akt proteins decreased. In addition, the protein levels of cyclin D3, cyclin B1, CDK1, CDK2, and CDK4 were downregulated while the expression levels of p21, p27, and p53 were upregulated significantly.

CONCLUSION

Galangin could suppress the viability of MCF-7 cells and induce cell apoptosis via the mitochondrial pathway and PI3K/Akt inhibition as well as cell cycle arrest.

Integrated multi-omics data analysis identifying novel drug sensitivity-associated molecular targets of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and the third-leading cause of malignancy-associated mortality worldwide. HCC cells are highly resistant to chemotherapeutic agents. Therefore, there are currently only two US Food and Drug Administration-approved drugs available for the treatment of HCC. The objective of the present study was to analyze the results of previously published high-throughput drug screening, and in vitro genomic and transcriptomic data from HCC cell lines, and to integrate the obtained results to define the underlying molecular mechanisms of drug sensitivity and resistance in HCC cells. The results of treatment with 225 different small molecules on 14 different HCC cell lines were retrieved from the Genomics of Drug Sensitivity in Cancer database and analyzed. Cluster analysis using the treatment results determined that HCC cell lines consist of two groups, according to their drug response profiles. Continued analyses of these two groups with Gene Set Enrichment Analysis method revealed 6 treatment-sensitive molecular targets (epidermal growth factor receptor, mechanistic target of rapamycin, deoxyribonucleic acid-dependent protein kinase, the Aurora kinases, Bruton's tyrosine kinase and phosphoinositide 3-kinase; all P<0.05) and partially effective drugs. Genetic and genome-wide gene expression data analyses of the determined targets and their known biological partners revealed 2 somatically mutated and 13 differentially expressed genes, which differed between drug-resistant and drug-sensitive HCC cells. Integration of the obtained data into a short molecular pathway revealed a drug treatment-sensitive signaling axis in HCC cells. In conclusion, the results of the present study provide novel drug sensitivity-associated molecular targets for the development of novel personalized and targeted molecular therapies against HCC.

Autophagic compound database: A resource connecting autophagy-modulating compounds, their potential targets and relevant diseases

OBJECTIVES

Autophagy, a highly conserved lysosomal degradation process in eukaryotic cells, can digest long-lived proteins and damaged organelles through vesicular trafficking pathways. Nowadays, mechanisms of autophagy have been gradually elucidated and thus the discovery of small-molecule drugs targeting autophagy has always been drawing much attention. So far, some autophagy-related web servers have been available online to facilitate scientists to obtain the information relevant to autophagy conveniently, such as HADb, CTLPScanner, iLIR server and ncRDeathDB. However, to the best of our knowledge, there is not any web server available about the autophagy-modulating compounds.

METHODS

According to published articles, all the compounds and their relations with autophagy were anatomized. Subsequently, an online Autophagic Compound Database (ACDB) (http://www.acdbliulab.com/) was constructed, which contained information of 357 compounds with 164 corresponding signalling pathways and potential targets in different diseases.

RESULTS

We achieved a great deal of information of autophagy-modulating compounds, including compounds, targets/pathways and diseases. ACDB is a valuable resource for users to access to more than 300 curated small-molecule compounds correlated with autophagy.

CONCLUSIONS

Autophagic compound database will facilitate to the discovery of more novel therapeutic drugs in the near future.

Galangin increases ERK1/2 phosphorylation to decrease ADAM9 expression and prevents invasion in A172 glioma cells

Galangin (3,5,7‑trihydroxyflavone), is a natural flavonoid present in plants. Galangin is reported to exhibit anti‑cancer properties against various cancer types. The aim of the present study was to display the effects of galangin on glioma and its mechanism of action in A172 human glioma cancer cells. The results clearly indicated that treatment of galangin inhibited A172 cell migration and invasion under non‑toxic doses. A human proteinase array assay was conducted to elucidate the potential effects of galangin, and the obtained results demonstrated that treatment of galangin inhibited ADAM9 protein expression and mRNA expression, that are known to contribute to cancer progression. Sustained extracellular signal‑regulated kinase (Erk)1/2 activation was also monitored, which contributed to ADAM9 protein expression and mRNA inhibition as investigated using western blotting analysis and reverse transcription‑quantitative polymerase chain reaction experiment. Erk1/2 inhibition by inhibitor or small interfering (si)Erk transfection markedly terminated galangin‑inhibited A172 migration and invasion via an Erk1/2 activation mechanism. Collective results suggested that galangin may act as an effective chemotherapeutic agent for glioma cancer depending on its ability to bring about ADAM9 and Erk1/2 activation.

The antioxidant, cytotoxic, and antigenotoxic effects of galangin, puerarin, and ursolic acid in mammalian cells

Phenolic compounds not only contribute to the sensory qualities of fruits and vegetables but also exhibit several health protective properties. Galangin, puerarin, and ursolic acid are commonly used plant phenolics in folk medicine. In this study, the antioxidant capacities of galangin, puerarin, and ursolic acid by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxic effects by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in V79 cells were investigated. The genotoxic potentials of galangin, puerarin, and ursolic acid were evaluated by micronucleus (MN) and alkaline COMET assays in human lymphocytes and in V79 cells. Galangin, puerarin, and ursolic acid (10, 100, 500, 1000, 2000, 5000, 10 000, and 20 000 μM) were found to have antioxidant activities at the studied concentrations. IC50 values of galangin, puerarin, and ursolic acid in V79 cells were found to be 275.48 μM, 2503.712 μM, and 224.85 μM, respectively. Galangin, puerarin, and ursolic acid, at the all concentrations, have not exerted genotoxic effects and galangin, puerarin, and ursolic acid revealed a reduction in the frequency of MN and DNA damage induced by H2O2.

Synthesis, characterization and in vitro and in vivo photodynamic activities of a gallium(iii) tris(ethoxycarbonyl)corrole

A gallium(iii) tris(ethoxycarbonyl)corrole is a highly effective photosensitizer against A549 cancer cells via p38 MAPK signaling cascade pathways.

Galangin Induces Autophagy via Deacetylation of LC3 by SIRT1 in HepG2 Cells

Galangin suppresses proliferation and induces apoptosis and autophagy in hepatocellular carcinoma (HCC) cells, but the precise mechanism is not clear. In this study, we demonstrated that galangin induced autophagy, enhanced the binding of SIRT1-LC3 and reduced the acetylation of endogenous LC3 in HepG2 cells. But this autophagy was inhibited by inactivation of SIRT1 meanwhile, galangin failed to reduce the acetylation of endogenous LC3 after SIRT1 was knocked-down. Collectively, these findings demonstrate a new mechanism by which galangin induces autophagy via the deacetylation of endogenous LC3 by SIRT1.

Ampelopsin Improves Insulin Resistance by Activating PPARγ and Subsequently Up-Regulating FGF21-AMPK Signaling Pathway

Ampelopsin (APL), a major bioactive constituent of Ampelopsis grossedentata, exerts a number of biological effects. Here, we explored the anti-diabetic activity of APL and elucidate the underlying mechanism of this action. In palmitate-induced insulin resistance of L6 myotubes, APL treatment markedly up- regulated phosphorylated insulin receptor substrate-1 and protein kinase B, along with a corresponding increase of glucose uptake capacity. APL treatment also increased expressions of fibroblast growth factor (FGF21) and phosphorylated adenosine 5’-monophosphate -activated protein kinase (p-AMPK), however inhibiting AMPK by Compound C or AMPK siRNA, or blockage of FGF21 by FGF21 siRNA, obviously weakened APL -induced increases of FGF21 and p-AMPK as well as glucose uptake capacity in palmitate -pretreated L6 myotubes. Furthermore, APL could activate PPAR γ resulting in increases of glucose uptake capacity and expressions of FGF21 and p-AMPK in palmitate -pretreated L6 myotubes, whereas all those effects were obviously abolished by addition of GW9662, a specific inhibitor of peroxisome proliferator- activated receptor –γ (PPARγ), and PPARγsiRNA. Using molecular modeling and the luciferase reporter assays, we observed that APL could dock with the catalytic domain of PPARγ and dose-dependently up-regulate PPARγ activity. In summary, APL maybe a potential agonist of PPARγ and promotes insulin sensitization by activating PPARγ and subsequently regulating FGF21- AMPK signaling pathway. These results provide new insights into the protective health effects of APL, especially for the treatment of Type 2 diabetes mellitus.

Galangin sensitizes TRAIL-induced apoptosis through down-regulation of anti-apoptotic proteins in renal carcinoma Caki cells

Galangin, bioflavonoids, has been shown anti-cancer properties in various cancer cells. In this study, we investigated whether galangin could enhance TRAIL-mediated apoptosis in TRAIL resistant renal carcinoma Caki cells. Galangin alone and TRAIL alone had no effect on apoptosis, while combined treatment with galangin and TRAIL significantly induced apoptosis in renal carcinoma (Caki, ACHN and A498) but not normal cells (normal mouse kidney cells and human normal mesangial cells). Galangin induced down-regulation of Bcl-2 protein at the transcriptional level via inhibition of NF-κB activation but not p53 pathway. Furthermore, galangin induced down-regulation of cFLIP, Mcl-1 and survivin expression at the post-translational levels, and the over-expression of Bcl-2, cFLIP, Mcl-1 and survivin markedly reduced galangin-induced TRAIL sensitization. In addition, galangin increased proteasome activity, but galangin had no effect on expression of proteasome subunits (PSMA5 and PSMD4). In conclusion, our investigation suggests that galangin is a potent candidate for sensitizer of TRAIL resistant cancer cell therapy.

Dihydromyricetin improves skeletal muscle insulin resistance by inducing autophagy via the AMPK signaling pathway

Skeletal muscle insulin resistance (SMIR) plays an important role in the pathogenesis of type 2 diabetes. Dihydromyricetin (DHM), a natural flavonoid, exerts various bioactivities including anti-oxidative and hepatoprotective effects. Herein, we intended to determine the effect of DHM on SMIR and the underlying mechanisms. We found that DHM increased the expression of phosphorylated insulin receptor substrate-1, phosphorylated Akt and glucose uptake capacity in palmitate-treated L6 myotubes under insulin-stimulated conditions. The expression of light chain 3, Beclin 1, autophagy-related gene 5 (Atg5), the degradation of sequestosome 1 and the formation of autophagosomes were also upregulated by DHM. Suppression of autophagy by 3-methyladenine and bafilomycin A1 or Atg5 and Beclin1 siRNA abolished the favorable effects of DHM on SMIR. Furthermore, DHM increased the levels of phosphorylated AMP-activated protein kinase (AMPK) and Ulk1, and decreased phosphorylated mTOR levels. AMPK inhibitor compound C (CC) and AMPK siRNA abrogated DHM-induced autophagy, subsequently suppressed DHM-induced SMIR improvement. Additionally, DHM inhibited the activity of F1F0-ATPase thereby activating AMPK. Finally, the results of in vivo study conducted in high fat diet-fed rats were consistent with the findings of in vitro study. In conclusion, DHM improved SMIR by inducing autophagy via the activation of AMPK signaling pathway.

Dietary compounds galangin and myricetin suppress ovarian cancer cell angiogenesis

Galangin and myricetin are flavonoids isolated from vegetables and fruits which exhibit anti-proliferative activity in human cancer cells. In this study, their anti-angiogenic effects were investigated with in vitro (HUVEC) and in vivo (CAM) models, which showed that galangin and myricetin inhibited angiogenesis induced by OVCAR-3 cells. The molecular mechanisms through which galangin and myricetin suppress angiogenesis were also studied. It was observed that galangin and myricetin inhibited secretion of the key angiogenesis mediator vascular endothelial growth factor (VEGF) and decreased levels of p-Akt, p-70S6K and hypoxia-inducible factor-1α (HIF-1α) proteins in A2780/CP70 and OVCAR-3 cells. Transient transfection experiments showed that galangin and myricetin inhibited secretion of VEGF by the Akt/p70S6K/ HIF-1α pathway. Moreover, a novel pathway, p21/HIF-1α/VEGF, was found to be involved in the inhibitory effect of myricetin on angiogenesis in OVCAR-3 cells. These data suggest that galangin and myricetin might serve as potential anti-angiogenic agents in the prevention of ovarian cancers dependent on new blood vessel networks.

Monoamine oxidase inhibitory constituents of propolis: kinetics and mechanism of inhibition of recombinant human MAO-A and MAO-B

Propolis is the resinous material that bees gather from leaf buds, flowers and vegetables. Propolis extracts contain constituents with a broad spectra of pharmacological properties and are important ingredients of popular dietary supplements. Propolis extracts were evaluated in vitro for inhibition of recombinant human monoamine oxidase (MAO)-A and MAO-B. The dichloromethane extract of propolis showed potent inhibition of human MAO-A and MAO-B. Further fractionation identified the most active fractions as rich in flavonoids. Galangin and apigenin were identified as the principal MAO-inhibitory constituents. Inhibition of MAO-A by galangin was about 36 times more selective than MAO-B, while apigenin selectivity for MAO-A vs. MAO-B was about 1.7 fold. Apigenin inhibited MAO-B significantly more potently than galangin. Galangin and apigenin were further evaluated for kinetic characteristics and the mechanism for the enzymes’ inhibition. Binding of galangin and apigenin with MAO-A and -B was not time-dependent and was reversible, as suggested by enzyme-inhibitor binding and dissociation-dialysis assay. The inhibition kinetics studies suggested that galangin and apigenin inhibited MAO-A and -B by a competitive mechanism. Presence of prominent MAO inhibitory constituents in propolis products suggests their potential for eliciting pharmacological effects that might be useful in depression or other neurological disorders. The results may also have important implications in drug-dietary supplement interactions.

Galangin suppresses HepG2 cell proliferation by activating the TGF-β receptor/Smad pathway

Galangin can suppress hepatocellular carcinoma (HCC) cell proliferation. In this study, we demonstrated that galangin induced autophagy by activating the transforming growth factor (TGF)-β receptor/Smad pathway and increased TGF-β receptor I (RI), TGF-βRII, Smad1, Smad2, Smad3 and Smad4 levels but decreased Smad6 and Smad7 levels. Autophagy induced by galangin appears to depend on the TGF-β receptor/Smad signalling pathway because the down-regulation of Smad4 by siRNA or inhibition of TGF-β receptor activation by LY2109761 blocked galangin-induced autophagy. The down-regulation of Beclin1, autophagy-related gene (ATG) 16L, ATG12 and ATG3 restored HepG2 cell proliferation and prevented galangin-induced apoptosis. Our findings indicate a novel mechanism for galangin-induced autophagy via activation of the TGF-β receptor/Smad pathway. The induction of autophagy thus reflects the anti-proliferation effect of galangin on HCC cells.

The role of AMP-activated protein kinase in quercetin-induced apoptosis of HL-60 cells

Our previous studies have shown that quercetin inhibits Cox-2 and Bcl-2 expressions, and induces human leukemia HL-60 cell apoptosis. In order to investigate the role of AMP-activated protein kinase (AMPK) on quercetin-induced apoptosis of HL-60 cells, we used flow cytometry to detect cell apoptosis. The expressions of LKB1, phosphorylated AMPK (p-AMPK), and Cox-2 protein were detected in HL-60 cells and normal peripheral blood mononuclear cells (PBMCs) by western blot. The expressions of LKB1, p-AMPK, and Cox-2 were detected in HL-60 cells after culture with quercetin. The expressions of p-AMPK were detected in HL-60 cells after culture with AMPK inhibitor Compound C. Then, the expressions of LKB1, p-AMPK, and Cox-2 were detected in HL-60 cells after culture with quercetin alone or quercetin + Compound C. It was found that there was no significant difference in LKB1 between PBMCs and HL-60. p-AMPK in PBMCs was higher than that in HL-60, while Cox-2 was lower. After culture of HL-60 with quercetin, p-AMPK was increased, Cox-2 was decreased, but LKB1 remained unchanged. After culture of HL-60 with Compound C, p-AMPK was decreased. There was no significant difference in LKB1 between the quercetin-alone and the quercetin + Compound C groups. p-AMPK decreased more significantly, while Cox-2 increased more significantly in the quercetin + Compound C groups than those in the quercetin-alone groups. Taken together, these findings suggested that quercetin activates AMPK expression in HL-60 cells independent of LKB1 activation, inhibits Cox-2 expression by activating AMPK, and further regulates the Bcl-2-dependent pathways of apoptosis to exert its anti-leukemia effect.