Induction of apoptosis by esculetin in human leukemia U937 cells: Roles of Bcl-2 and extracellular-regulated kinase signaling

Assessment of sedative activity of fraxin: In vivo approach along with receptor binding affinity and molecular interaction with GABAergic system

Insomnia is a sleep disorder in which you have trouble falling and/or staying asleep. This research aims to evaluate the sedative effects of fraxin (FX) on sleeping mice induced by thiopental sodium (TS). In addition, a molecular docking study was conducted to investigate the molecular processes underlying these effects. The study used adult male Swiss albino mice and administered FX (10 and 20 mg/kg, i.p.) and diazepam (DZP) (2 mg/kg) either separately or in combination within the different groups to examine their modulatory effects. After a period of 30 min, the mice that had been treated were administered (TS: 20 mg/kg, i.p.) to induce sleep. The onset of sleep for the mice and the length of their sleep were manually recorded. Additionally, a computational analysis was conducted to predict the role of gamma-aminobutyric acid (GABA) receptors in the sleep process and evaluate their pharmacokinetics and toxicity. The outcomes indicated that FX extended the length of sleep and reduced the time it took to fall asleep. When the combined treatment of FX and DZP showed synergistic sedative action. Also, FX had a binding affinity of -7.2 kcal/mol, while DZP showed -8.4 kcal/mol. The pharmacokinetic investigation of FX demonstrated favorable drug-likeness and strong pharmacokinetic characteristics. Ultimately, FX demonstrated a strong sedative impact in the mouse model, likely via interacting with the GABAA receptor pathways.

Esculetin unveiled: Decoding its anti-tumor potential through molecular mechanisms-A comprehensive review

BACKGROUND

The growing complexity of cancer has made it a significant concern in the medical community. Although cancer research has advanced, it is still challenging to create new effective medications due to the limitations and side effects of existing treatment strategies. These are enforcing the development of some alternative drugs from natural compounds with fewer drawbacks and side effects.

AIM

Therefore, this review aims to provide up-to-date, crucial, and all-encompassing data on esculetin's anticancer activity, including all relevant molecular and cellular processes based on in vivo and in vitro investigations.

RESULTS

According to the literature review, esculetin is available in nature and is effective against 16 different types of cancer. The general mechanism shown by esculetin is modulating signaling cascades and its related pathways, like cell proliferation, cell growth, autophagy, apoptosis, necrosis, inflammation, angiogenesis, metastasis, invasion, and DNA damage. Nanoformulation of esculetin improves this natural product's efficacy by improving water solubility. Esculetin's synergistic effects with both natural substances and conventional treatments have been shown, and this method aids in reversing resistance mechanisms by modulating resistance-related proteins. In addition, it has fewer side effects on humans than other phytochemicals and standard drugs with some good pharmacokinetic features.

CONCLUSION

Therefore, until standard chemotherapeutics are available in pharmaceutical markets, esculetin should be used as a therapeutic drug against various cancer types.

Artemisia scoparia and Metabolic Health: Untapped Potential of an Ancient Remedy for Modern Use

Botanicals have a long history of medicinal use for a multitude of ailments, and many modern pharmaceuticals were originally isolated from plants or derived from phytochemicals. Among these, artemisinin, first isolated from Artemisia annua, is the foundation for standard anti-malarial therapies. Plants of the genus Artemisia are among the most common herbal remedies across Asia and Central Europe. The species Artemisia scoparia (SCOPA) is widely used in traditional folk medicine for various liver diseases and inflammatory conditions, as well as for infections, fever, pain, cancer, and diabetes. Modern in vivo and in vitro studies have now investigated SCOPA's effects on these pathologies and its ability to mitigate hepatotoxicity, oxidative stress, obesity, diabetes, and other disease states. This review focuses on the effects of SCOPA that are particularly relevant to metabolic health. Indeed, in recent years, an ethanolic extract of SCOPA has been shown to enhance differentiation of cultured adipocytes and to share some properties of thiazolidinediones (TZDs), a class of insulin-sensitizing agonists of the adipogenic transcription factor PPARγ. In a mouse model of diet-induced obesity, SCOPA diet supplementation lowered fasting insulin and glucose levels, while inducing metabolically favorable changes in adipose tissue and liver. These observations are consistent with many lines of evidence from various tissues and cell types known to contribute to metabolic homeostasis, including immune cells, hepatocytes, and pancreatic beta-cells. Compounds belonging to several classes of phytochemicals have been implicated in these effects, and we provide an overview of these bioactives. The ongoing global epidemics of obesity and metabolic disease clearly require novel therapeutic approaches. While the mechanisms involved in SCOPA's effects on metabolic, anti-inflammatory, and oxidative stress pathways are not fully characterized, current data support further investigation of this plant and its bioactives as potential therapeutic agents in obesity-related metabolic dysfunction and many other conditions.

The emerging role of targeting cancer metabolism for cancer therapy

Glucose, as the main consuming nutrient of the body, faces different destinies in cancer cells. Glycolysis, oxidative phosphorylation, and pentose phosphate pathways produce different glucose-derived metabolites and thus affect cells' bioenergetics differently. Tumor cells' dependency to aerobic glycolysis and other cancer-specific metabolism changes are known as the cancer hallmarks, distinct cancer cells from normal cells. Therefore, these tumor-specific characteristics receive the limelight as targets for cancer therapy. Glutamine, serine, and fatty acid oxidation together with 5-lipoxygenase are main pathways that have attracted lots of attention for cancer therapy. In this review, we not only discuss different tumor metabolism aspects but also discuss the metabolism roles in the promotion of cancer cells at different stages and their difference with normal cells. Besides, we dissect the inhibitors potential in blocking the main metabolic pathways to introduce the effective and non-effective inhibitors in the field.

Chemical Constituents from Fraxinus hupehensis and Their Antifungal and Herbicidal Activities

The phytochemical investigation of Fraxinus hupehensis led to the isolation and characterization of ten compounds which were identified as fraxin (1), fraxetin (2), esculetin (3), cichoriin (4), euphorbetin (5), kaempferol-3-O-β-rutinoside (6), oleuropein (7), linoleic acid (8), methyl linoleate (9), and β-sitosterol (10). Structures of the isolated constituents were characterized by ¹H NMR, ¹³C NMR and HRMS. All the compounds, except compounds 3 and 4, were isolated for the first time from this plant. Further, this was the first report for the occurrence of compound 5 in the Fraxinus species. Antifungal activity evaluation showed that compound 2 exhibited significant inhibitory effects against Bipolaris maydis, Sclerotium rolfsii, and Alternaria solani with EC₅₀ values of 0.31 ± 0.01 mmol/L, 10.50 ± 0.02 mmol/L, and 0.40 ± 0.02 mmol/L respectively, compared to the positive control, Carbendazim, with its EC₅₀ values of 0.74 ± 0.01 mmol/L, 1.78 ± 0.01 mmol/L and 1.41 ± 0.00 mmol/L. Herbicidal activity tests showed that compounds 8-10 had strong inhibitory effects against the roots of Echinochloa crus-galli with EC₅₀ values of 1.16 ± 0.23 mmol/L, 1.28 ± 0.58 mmol/L and 1.33 ± 0.35 mmol/L respectively, more potently active than that of the positive control, Cyanazine, with its EC₅₀ values of 1.56 ± 0.44 mmol/L. However, none of the compounds proved to be active against the tested bacteria (Erwinia carotovora, Pseudomonas syringae, and Ralstonia solanacearum).

Decitabine promotes apoptosis in mesenchymal stromal cells isolated from patients with myelodysplastic syndromes by inducing reactive oxygen species generation

Myelodysplastic syndromes (MDSs) are a group of clonal disorders of hematopoietic stem cells, resulting in ineffective hematopoiesis. Previous studies have reported that decitabine (DAC) plays an essential role in cell cycle arrest and cell death induction in multiple cell types. Nevertheless, the effect of decitabine on mesenchymal stromal cells derived from bone marrow of patients with MDSs is not completely clarified. Here, we explored the apoptotic and anti-proliferative effect of DAC on MSCs isolated from patients with MDSs. Treatment with DAC inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis. We found a positive relationship between cell death triggered by DAC in MSCs and the death receptor family members Fas and FasL mRNA and protein levels (***P < 0.00085), cleaved caspase (-3, -8, and -9) activity, and mitochondrial membrane potential reduction. Additionally, DAC-induced apoptosis was inhibited by Kp7-6, a FasL/Fas antagonist, indicating a crucial role of FasL/Fas, a cell death receptor, in mediating the apoptotic effect of DAC. DAC also induced reactive oxygen species (ROS) generation in MSCs derived from MDSs patients (*P = 0.038). Furthermore, N-acetyl-L-cysteine (NAC), a widely accepted ROS scavenger, efficiently reversed DAC-induced apoptosis by inhibiting ROS generation (***P < 0.00051) in mitochondria and restoring mitochondrial membrane potential. Furthermore, ROS production was found to be a consequence of caspase activation via caspases inhibition. Our data imply that DAC triggers ROS production in human MSCs, which serves as a crucial factor for mitochondrial membrane potential reduction, and DAC induces cell death prior to FasL/Fas stimulation.

Animal study of the anti-diarrhea effect and microbial diversity of dark tea produced by the Yao population of Guangxi

Chinese dark teas (CDTs) are a special type of tea traditionally consumed by ethnic minorities around the border regions of China.

Different roles of Nrf2 and NFKB in the antioxidant imbalance produced by esculetin or quercetin on NB4 leukemia cells

Esculetin (6,7-dihydrocoumarin) and the flavonoid quercetin (3,5,7,3',4' pentahydroxyflavone) are compounds that could change the balance of redox homeostasis. NB4 leukemia cells were treated with 25 μM quercetin for 24 h and with esculetin at either 100 or 500 μM for different times. Quercetin increased the levels of pro-inflammatory NFkB p65 in the nucleus correspondingly reducing them in the cytosol. The levels of NFkB p65 decreased in the nucleus at high esculetin concentration treatments for long times (19 h), concomitantly increasing the levels of anti-inflammatory NFkB p50 in the nucleus. This could suggest formation of inhibitory p50 homodimers possibly related with anti-inflammatory response. Lipoxygenase expression was reduced either by esculetin or quercetin. A significant increase of Nrf2 in the nucleus of NB4 cells treated with 100 μM esculetin for 19 h was observed. Quercetin increased the levels of Nrf2 in the cytosol reducing them in the nucleus. Superoxide dismutase expression increased in NB4 cells treated with esculetin in contrast with quercetin. All these data support a relevant differential role for NFkB and Nrf2 in anti-inflammatory and redox response when apoptosis was induced by esculetin or quercetin in human leukemia NB4 cells.

Esculetin exerts antitumor effect on human gastric cancer cells through IGF-1/PI3K/Akt signaling pathway

In this study, we aimed to investigate the antitumor effect of esculetin, a coumarin derivative extracted from natural plants, on human gastric cancer cells, and to illustrate the potential mechanisms. The results showed that esculetin exhibited anti-proliferative effects against gastric cancer cells and induced their apoptosis in a dose dependent manner with lower toxicity against normal gastric epithelial cells. Mechanism study indicated that esculetin induced gastric cancer MGC-803 cells apoptosis by triggering the activation of mitochondrial apoptotic pathway through reducing the mitochondrial membrane potential (MMP), increasing Bax/Bcl-2 ratio, activating caspase-3 and caspase-9 activity, and increasing cytochrome c release from mitochondria. Further study showed that the pro-apoptotic effects of esculetin were associated with down-regulation of insulin-like growth factor-1/ phosphatidylinositide 3-kinase/protein kinase B (IGF-1/PI3K/Akt) signaling pathway. Activation of IGF-1/PI3K/Akt pathway by IGF-1 abrogated the pro-apoptotic effects of esculetin, while inhibition of IGF-1/PI3K/Akt pathway by triciribine or LY294002 enhanced the pro-apoptotic effects of esculetin. In addition, esculetin inhibited in vivo tumor growth with no obvious toxicity following subcutaneous inoculation of MGC-803 cells in nude mice, and inhibited activation of IGF-1/PI3K/Akt pathway in tumor tissue.

CONCLUSION

These results indicate that esculetin could inhibit cell proliferation and induce apoptosis of gastric cancer cells through IGF-1/PI3K/Akt mediated mitochondrial apoptosis pathway, and may be a novel effective chemotherapeutic agent against gastric cancer.

Esculetin Neutralises Cytotoxicity of t-BHP but Not of H2O2 on Human Leukaemia NB4 Cells

The coumarin esculetin shows antioxidant action on some cell types, both by scavenging ROS and by decreasing ROS production. We have previously demonstrated the induction of apoptosis by esculetin on NB4 human leukaemia cells by an ill-defined mechanism related to ROS levels. In this work, we analyze the effect of the simultaneous treatment with esculetin and two oxidants to observe the early events in the mechanism of esculetin-induced apoptosis. Our results show that, from the early time of 15 min, esculetin acts synergistically with H₂O₂ to decrease cell viability and metabolic activity and to increase apoptosis in NB4 cells. In contrast, the early oxidative effects of t-BHP are neutralised by esculetin, protecting human leukaemia NB4 cells from apoptosis. Esculetin seems to restrict the increase in peroxides caused by H₂O₂ or t-BHP in the time interval analyzed. These results contribute to a better understanding of the cytotoxic effect caused by esculetin on NB4 cells. At the same time, the early neutralisation of exogenous oxidants could be of interest to prevent diseases related to oxidative stress imbalance.

Esculetin induces antiproliferative and apoptotic response in pancreatic cancer cells by directly binding to KEAP1

BACKGROUND

A handful of studies have exploited antitumor potential of esculetin, a dihydroxy coumarine derivative; the targets to which it binds and the possible downstream mechanism for its cytotoxicity in cancer cells remain to be elucidated. Using pancreatic cancer cell lines as a model system, herein the study was initiated to check the efficacy of esculetin in inhibiting growth of these cancer cells, to decipher mechanism of its action and to predict its direct binding target protein.

METHODS

The cytotoxicity of esculetin was determined in PANC-1, MIA PaCa-2 and AsPC-1 cell lines; followed by an inspection of intracellular levels of ROS and its associated transcription factor, p65-NF-κB. The interaction between transcription factor, Nrf2 and its regulator KEAP1 was studied in the presence and absence of esculetin. The effect of Nrf2 on gene expression of antioxidant response element pathway was monitored by real time PCR. Thereafter, potential binding target of esculetin was predicted through molecular docking and then confirmed in vitro.

RESULTS

Esculetin treatment in all three pancreatic cancer cell lines resulted in significant growth inhibition with G1-phase cell cycle arrest and induction of mitochondrial dependent apoptosis through activation of caspases 3, 8 and 9. A notable decrease was observed in intracellular ROS and protein levels of p65-NF-κB in PANC-1 cells on esculetin treatment. Antioxidant response regulator Nrf2 has been reportedly involved in crosstalk with NF-κB. Interaction between Nrf2 and KEAP1 was found to be lost upon esculetin treatment in PANC-1 and MIA Paca-2 cells. Nuclear accumulation of Nrf2 and an upregulation of expression of Nrf2 regulated gene NQO1, observed on esculetin treatment in PANC-1 further supported the activation of Nrf2. To account for the loss of Nrf2-KEAP1 interaction on esculetin treatment, direct binding potential between esculetin and KEAP1 was depicted in silico using molecular docking studies. Pull down assay using esculetin conjugated sepharose beads confirmed the binding between esculetin and KEAP1.

CONCLUSIONS

We propose that esculetin binds to KEAP1 and inhibits its interaction with Nrf2 in pancreatic cancer cells. This thereby promotes nuclear accumulation of Nrf2 in PANC-1 cells that induces antiproliferative and apoptotic response possibly by attenuating NF-κB.

Inula Viscosa Extracts Induces Telomere Shortening and Apoptosis in Cancer Cells and Overcome Drug Resistance

Telomerase is activated in human papillomavirus (HPV) positive cervical cancer and targeting telomeres offers a novel anticancer therapeutic strategy. In this study, the telomere targeting properties, the cytotoxic as well as the pro-apoptotic effects of hexane (IV-HE) and dichloromethane (IV-DF) fractions from Inula viscosa L. extracts were investigated on human cervical HeLa and SiHa cancer cells. Our data demonstrate that IV-HE and IV-DF extracts were able to inhibit cell growth in HeLa and SiHa cells in a dose-dependent manner and studied resistant cell lines exhibited a resistance factor less than 2 when treated with the extracts. IV-HE and IV-DF extracts were able to inhibit telomerase activity and to induce telomere shortening as shown by telomeric repeat amplification protocol and TTAGGG telomere length assay, respectively. The sensitivity of fibroblasts to the extracts was increased when telomerase was expressed. Finally, IV-HE and IV-DF were able to induce apoptosis as evidenced by an increase in annexin-V labeling and caspase-3 activity. This study provides the first evidence that the IV-HE and IV-DF extracts from Inula viscosa L. target telomeres induce apoptosis and overcome drug resistance in tumor cells. Future studies will focus on the identification of the molecules involved in the anticancer activity.

Metformin Induces Cell Cycle Arrest and Apoptosis in Drug-Resistant Leukemia Cells

Recent epidemiological studies indicate that the antidiabetic drug metformin has chemosensitizing and chemopreventive effects against carcinogenesis. Here, we demonstrate that metformin exerts varying degrees of antitumor activity against human leukemia cells, as reflected by differences in growth inhibition, apoptosis, and alterations to metabolic enzymes. In metformin-sensitive cells, autophagy was not induced but rather it blocked proliferation by means of arresting cells in the S and G2/M phases which was associated with the downregulation of cyclin A, cyclin B1, and cdc2, but not that of cyclin E. In 10E₁-CEM cells that overexpress Bcl-2 and are drug-resistant, the effect of metformin on proliferation was more pronounced, also inducing the activation of the caspases 3/7 and hence apoptosis. In all sensitive cells, metformin decreased the Δψ_m and it modified the expression of enzymes involved in energy metabolism: PKCε (PKCepsilon) and PKCδ (PKCdelta). In sensitive cells, metformin altered PKCε and PKCδ expression leading to a predominance of PKCε over PKCδ which implies a more glycolytic state. The opposite occurs in the nonresponsive cells. In conclusion, we provide new insights into the activity of metformin as an antitumoral agent in leukemia cells that could be related to its capability to modulate energy metabolism.

p-Methoxycinnamic acid, an active phenylpropanoid induces mitochondrial mediated apoptosis in HCT-116 human colon adenocarcinoma cell line

Among the eight phytochemicals (dihydrocarveol, sinapic acid, vanillic acid, ethylgallate, myrtenol, transcarveol, p-methoxycinnamic acid, and isoferulic acid) we tested, p-methoxycinnamic acid (p-MCA) [10 μM] showed the most potent in vitro growth inhibition on human colon adenocarcinoma (HCT-116 cells). Antiproliferative activity of p-MCA at 24h was associated with DNA damage, morphological changes and the results were comparable with doxorubicin. p-MCA induced phosphatidylserine translocation, increased the levels of reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC) and decreased enzymic antioxidant status (SOD, CAT, GPx) in HCT-116. p-MCA treatment increased the percentage of apoptotic cells, decreased the mitochondrial membrane potential and triggered cytochrome C release to cytosol. The induction of apoptosis by p-MCA was accompanied by an increase in caspase 3 and caspase 9 activities, increased expression of Bax and decreased expression of Bcl-2. Thus p-MCA induces mitochondria mediated intrinsic pathway of apoptosis in HCT-116 and has potential for treatment and prevention of colon cancer.

Human acute promyelocytic leukemia NB4 cells are sensitive to esculetin through induction of an apoptotic mechanism

Acute promyelocytic leukemia (APL) is a type of cancer, in which immature cells called promyelocytes proliferate abnormally. Human NB4 cell line appears to be a suitable in vitro model to express the characteristics of APL. In this work, we have investigated the effects of esculetin, a coumarin derivative with antioxidant properties, on the viability, the induction of apoptosis and the expression of apoptotic factors in NB4 cells. Cells treated with esculetin at several concentrations (20-500 μM) and for different times (5-24 h) showed a concentration- and time-dependent viability decrease with increased subdiploid DNA production. Esculetin inhibited cell cycle progression and induced DNA fragmentation. Moreover, annexin-V-FITC cytometry assays suggested that increased toxicity is due to both early and late apoptosis. This apoptosis process is be mediated by activation of caspase-3 and caspase-9. Treatments with progressively increasing concentrations (from 100 μM to 500 μM) of esculetin produced a reduction of Bcl2/Bax ratio in NB4 cells at 19 h, without affecting p53 levels. Proapoptotic action of esculetin involves the ERK MAP kinase cascade since increased levels of phosphorylated ERK were observed after those treatments. Increments in the levels of phosphorylated-Akt were also observed. Additionally, esculetin induced the loss of mitochondrial membrane potential with a release of cytochrome c into the cytosol which starts at 6 h of treatment with esculetin and increases up to 24 h. Esculetin induced an increase in superoxide anion at long times of treatment and a reduction of peroxides at short times (1 h) with an observed increase at 2-4 h of treatment. No significant changes in NO production was observed. Esculetin reduced the GSH levels in a time-dependent manner. In summary, the present work shows the cytotoxic action of esculetin as an efficient tool to study apoptosis mechanism induction on NB4 cell line used as a relevant model of APL disease.

5-lipoxygenase antagonist therapy: a new approach towards targeted cancer chemotherapy

Leukotrienes are the bioactive group of fatty acids and major constituents of arachidonic acid metabolism molded by the catalytic activity of 5-lipoxygenase (5-LOX). Evidence is accumulating in support of the direct involvement of 5-LOX in the progression of different types of cancer including prostate, lung, colon, and colorectal cancers. Several independent studies now support the correlation between the 5-LOX expression and cancer cell viability, proliferation, cell migration, invasion through extracellular matrix destruction, metastasis, and activation of anti-apoptotic signaling cascades. The involvement of epidermal growth factor receptor and 5-oxo-ETE receptor (OXER1) is the major talking point in the downstream of the 5-LOX pathway, which relates the cancer cells to the proliferative pathways. Antisense technology approaches and use of different kinds of blocker targeted to 5-LOX, FLAP (5-LOX-activating protein), and OXER1 have shown a greater efficiency in combating different cancer cell types. Lastly, suppression of 5-LOX activity that reduces the cell proliferation activity also induces intrinsic mitochondrial apoptotic pathway in either p53-dependent or independent manner. Pharmacological agents that specifically inhibit the LOX-mediated signaling pathways have been used during last few years to treat inflammatory diseases such as asthma and arthritis. Studies of these well-characterized agents are therefore warranted for their use as possible candidates for chemotherapeutic studies against the killer disease cancer.

Structure-anti-leukemic activity relationship study of ortho-dihydroxycoumarins in U-937 cells: key role of the δ-lactone ring in determining differentiation-inducing potency and selective pro-apoptotic action

Previous studies indicated the need of at least one phenolic hydroxyl group in the coumarin core for induction of cytotoxicity in different cell lines. Herein, we present an exhaustive structure-activity relationship study including ortho-dihydroxycoumarins (o-DHC) derivatives, cinnamic acid derivatives (as open-chain coumarin analogues) and 1,2-pyrones (representative of the δ-lactone ring of the coumarin core), carried out to further identify the structural features of o-DHC required to induce leukemic cell differentiation and apoptosis in U-937 cells. Our results show for the first time that the δ-lactone ring positively influences the aforementioned biological effects, by conferring greater potency to compounds with an intact coumarin nucleus. Most tellingly, we reveal herein the crucial role of this molecular portion in determining the selective toxicity that o-DHC show for leukemic cells over normal blood cells. From a pharmacological perspective, our findings point out that o-DHC may be useful prototypes for the development of novel chemotherapeutic agents.

Induction of apoptosis by cordycepin via reactive oxygen species generation in human leukemia cells

Cordycepin (3'-deoxyadenosin), a specific polyadenylation inhibitor, is the main functional component in Cordyceps militaris, one of the top three renowned traditional Chinese medicines. Cordycepin has been shown to possess many pharmacological activities including immunological stimulation, and anti-bacterial, anti-viral, and anti-tumor effects. However, the mechanisms underlying its anti-cancer mechanisms are not yet understood. In this study, the apoptotic effects of cordycepin were investigated in human leukemia cells. Treatment with cordycepin significantly inhibited cell growth in a concentration-dependent manner by inducing apoptosis but not necrosis. This induction was associated with generation of reactive oxygen species (ROS), mitochondrial dysfunction, activation of caspases, and cleavage of poly(ADP-ribose) polymerase protein. However, apoptosis induced by cordycepin was attenuated by caspase inhibitors, indicating an important role for caspases in cordycepin responses. Administration of N-acetyl-l-cysteine, a scavenger of ROS, also significantly inhibited cordycepin-induced apoptosis and activation of caspases. These results support a mechanism whereby cordycepin induces apoptosis of human leukemia cells through a signaling cascade involving a ROS-mediated caspase pathway.