Hydroxychavicol, a Piper betle leaf component, induces apoptosis of CML cells through mitochondrial reactive oxygen species-dependent JNK and endothelial nitric oxide synthase activation and overrides imatinib resistance

Oxidative Stress and Chronic Myeloid Leukemia: A Balance between ROS-Mediated Pro- and Anti-Apoptotic Effects of Tyrosine Kinase Inhibitors

The balanced reciprocal translocation t (9; 22) (q34; q11) and the BCR-ABL fusion gene, which produce p210 bcr-abl protein production with high tyrosine kinase activity, are characteristics of chronic myeloid leukemia, a myeloproliferative neoplasm. This aberrant protein affects several signaling pathways connected to both apoptosis and cell proliferation. It has been demonstrated that tyrosine kinase inhibitor treatment in chronic myeloid leukemia acts by inducing oxidative stress and, depending on its level, can activate signaling pathways responsible for either apoptosis or survival in leukemic cells. Additionally, oxidative stress and reactive oxygen species generation also mediate apoptosis through genomic activation. Furthermore, it was shown that oxidative stress has a role in both BCR-ABL-independent and BCR-ABL-dependent resistance pathways to tyrosine kinases, while patients with chronic myeloid leukemia were found to have a significantly reduced antioxidant level. The ideal environment for tyrosine kinase inhibitor therapy is produced by a favorable oxidative status. We discuss the latest studies that aim to manipulate the redox system to alter the apoptosis of cancerous cells.

Targeting bone cancer with 4-Allylbenzene-1,2-diol purified from Piper betle L.: an in silico and cytotoxicity scrutiny

Piper betle L., a well-known medicinal plant with rich source of bioactive compounds, is widely used in several therapeutics. The present study was performed to scrutinize the anti-cancer potential of compounds P. betle petiole by means of in silico studies, purification of 4-Allylbenzene-1,2-diol from petioles and assessing its cytotoxicity on bone cancer metastasis. Subsequent to SwissADME screening, 4-Allylbenzene-1,2-diol and Alpha terpineol were chosen for molecular docking together with eighteen approved drugs against fifteen important bone cancer targets accompanied with molecular dynamics simulation studies. 4-Allylbenzene-1,2-diol was found to be multi-targeting, interacted effectively with all targets, particularly exhibited good stability with MMP9 and MMP2 during molecular dynamics simulations and Molecular Mechanics- Generalized Born and Surface Area (MM-GBSA) analysis using Schrodinger. Later, the compound was isolated, purified and the cytotoxicity studies on MG63 bone cancer cell lines confirmed the cytotoxicity nature (75.98% at 100 µg/ml concentration). The results demonstrated the compound as a matrix metalloproteinase inhibitor, and therefore 4-Allylbenzene-1,2-diol may possibly be prescribed in targeted therapy for alleviating the bone cancer metastasis upon further wet lab experimental validations.Communicated by Ramaswamy H. Sarma.

Hydroxychavicol as a potential anticancer agent (Review)

Piper betle leaves are widely cultivated in Malaysia, India, Indonesia and Thailand. They have been used as a traditional medicine for centuries due to their medicinal properties, including antioxidant, antiproliferative, antibacterial, antifungal and anti-inflammatory properties, which are attributable to their high phenolic contents. Hydroxychavicol (HC), a primary constituent of P. betle leaves, is known to possess antiproliferative activity at micromolar doses on various cancer cell lines of different origins while leaving normal cells unharmed. The present review summarises the mechanisms of action of HC reported in the literature, reviews the scope of work done thus far and outlines the direction of future research on the potential of HC as an anticancer agent. PubMed, Scopus and Web of Science were searched using the keywords (hydroxychavicol OR 4-allylpyrocatechol OR 4-allylcatechol) AND (cancer OR carcinogenesis OR tumour OR carcinoma) to acquire research articles. In vitro studies reported several possible mechanisms for the chemopreventive effects of HC against cancer cell lines, including chronic myelogenous leukaemia (CML), prostate, glioma, breast and colorectal cancers, while in vivo studies encompassed investigations on Ehrlich ascites carcinoma cells in Swiss albino mice and a CML mouse model. These studies suggest that HC exerts its anticancer effect via the modulation of mitochondrial membrane potential and the c-Jun N-terminal kinase, mitogen-activated protein kinase and endoplasmic reticulum-unfolded protein responses pathways and the generation of reactive oxygen species. In summary, future research should focus on combinations of HC with other anticancer drugs and testing in animal models to evaluate its bioavailability, potency and tissue and dose selectivity.

Anticancer Potential of Hydroxychavicol Derived from Piper betle L: An in Silico and Cytotoxicity Study

Piper betle L. is a popular medicinal plant in Asia, and extracts of the plant leaf are used for several therapeutics. It is known for its rich source of phenolic compounds, including hydroxychavicol. Hydroxychavicol is an allylbenzene that has gained much attention due to its anticancer properties. The current study quantified and purified hydroxychavicol from P. betle L. and predicted its anticancer competence through in silico and cytotoxicity studies. Leaf samples of 22 P. betle L. accessions from different locations of Tamil Nadu, India, were analyzed using reverse phase-high performance liquid chromatography for quantification of hydroxychavicol. The highest quantity of hydroxychavicol was obtained from the accession BV22 (89.2%). Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis of hydroxychavicol using SwissADME satisfied the physicochemical property guidelines of Lipinski's Rule of Five, ensuring its drug-likeness behavior. Molecular docking studies confirmed the interaction of hydroxychavicol with all 16 tested cancer targets. In Vitro MTT assay of hydroxychavicol in bone cancer cell lines (MG63) also demonstrated the anticancer competency, indicating the requirement to formulate the molecule as a drug in treating various types of cancers.

Understanding the Molecular Mechanisms of Betel miRNAs on Human Health

BACKGROUND

Since ancient times, "betel leaf" (Piper betle) has been revered for its religious, cultural, and medicinal properties. Phytochemicals from the Piper betle are effective in a variety of conditions, including cancer. To date, however, no genomic study or evidence has been found to elucidate the regulatory mechanism that underpins its therapeutic properties. This is the first study of its kind to predict Piper betle miRNAs and also the first genomics source representation of Piper betle. According to previous research, miRNAs from the plants we eat can regulate gene expression. In line with this, our in-silico study revealed that Piper betle and human cross-kingdom control occurs.

METHOD

This study demonstrates the prediction and in-silico validation of Piper betle miRNAs from NGS-derived transcript sequences. The cross-kingdom regulation which can also be understood as inter-species RNA regulation was studied to identify human mRNA targets being controlled by Piper betle miRNAs. Functional annotation and gene-disease association of human targets were performed to understand the role of Piper betle miRNAs in human health and disease. The protein-protein interaction and expression study of targets was further carried out to decipher their role in cancer development.

RESULTS

Identified six Piper betle miRNAs belonging to miR156, miR164, miR172, and miR535 families were discovered to target 198 human mRNAs involved in various metabolic and disease processes. Angiogenesis and the cell surface signaling pathway were the most enriched gene ontology correlated with targets, both of which play a critical role in disease mechanisms, especially in the case of carcinoma. In an analysis of gene-disease interactions, 40 genes were found to be related to cancer. According to a protein-protein interaction, the CDK6 gene, which is thought to be a central regulator of cell cycle progression, was found as a hub protein, affecting the roles of CBFB, SAMD9, MDM4, AXIN2, and NOTCH2 onco genes. Further investigation revealed that pbe-miRNA164a can be used as a regulator to minimise disease severity in Acute Myeloid Leukemia, where CDK6 expression is highest compared to normal cells.

CONCLUSION

The predicted pbe-miRNA164a in this study can be a promising suppressor of CDK6 gene involved in tumour angiogenesis. In vivo validation of the pbe-miRNA164a mimic could pave the way for new opportunities to fight cancer and leverage the potential of Piper betle in the healthcare sector.

Imbalanced GSH/ROS and sequential cell death

Reactive oxygen species (ROS) are produced in cells during metabolic processes. Excessive intracellular ROS may react with large biomolecules, such as DNA, RNA, proteins, and small biomolecules, that is, glutathione (GSH) and unsaturated fatty acids. GSH has physiological functions, including free radical scavenging, anti-oxidation, and electrophile elimination. The disruption of ROS/GSH balance results in the deleterious oxidation and chemical modification of biomacromolecules, which eventually leads to cell-cycle arrest and proliferation inhibition, and even induces cell death. Imbalanced ROS/GSH may result from a direct increase of ROS, consumption of GSH, intracellular oxidoreductase interference, or thioredoxin activity reduction. Some chemicals including arsenic trioxide (ATO), pyrogallol (PG), and carbobenzoxy-Leu-Leu-leucinal (MG132) could also disrupt the balance of GSH and ROS. This article reviews the occurrence and consequences of the imbalance between GSH and ROS and introduces factors responsible for the disruption of cellular ROS and GSH balance, resulting in cell death. "GSH" and "ROS" were used as keywords to search the relevant literaturess.

Betel leaf extract and its major component hydroxychavicol promote osteogenesis and alleviate glucocorticoid-induced osteoporosis in rats

Piper betle leaves possess several ethnomedicinal properties and are immensely used in traditional medicinal practices in regions of Asian and African subcontinents. However, their effects in treating skeletal complications are least known. In this study, we evaluated cellular and molecular effects of betel leaf extract (BLE) and its major phytoconstituent, hydroxychavicol (HCV) in promoting osteogenesis in vitro and alleviating glucocorticoid induced osteoporosis (GIO) in vivo. Both BLE and HCV markedly stimulated osteoblast differentiation of C3H10T1/2 cells with increased expression of RUNX2 and osteopontin through the GSK-3β/β-catenin-signaling pathway. Also, oral administration of BLE and HCV in GIO rats resulted in restoration of bone mass and tissue microarchitecture. Thus, with our findings we conclude that BLE and HCV promote osteogenesis of C3H10T1/2 cells via the GSK-3β/β-catenin pathway and alleviate GIO in rats.

Hydroxychavicol, a polyphenol from Piper betle leaf extract, induces cell cycle arrest and apoptosis in TP53-resistant HT-29 colon cancer cells

This study aims to elucidate the antiproliferative mechanism of hydroxychavicol (HC). Its effects on cell cycle, apoptosis, and the expression of c-Jun N-terminal kinase (JNK) and P38 mitogen-activated protein kinase (MAPK) in HT-29 colon cancer cells were investigated. HC was isolated from Piper betle leaf (PBL) and verified by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC-MS). The cytotoxic effects of the standard drug 5-fluorouracil (5-FU), PBL water extract, and HC on HT-29 cells were measured after 24, 48, and 72 h of treatment. Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h. Changes in phosphorylated JNK (pJNK) and P38 (pP38) MAPK expression were observed up to 18 h. The half maximal inhibitory concentration (IC₅₀) values of HC (30 μg/mL) and PBL water extract (380 μg/mL) were achieved at 24 h, whereas the IC₅₀ of 5-FU (50 μmol/L) was obtained at 72 h. Cell cycle arrest at the G₀/G₁ phase in HC-treated cells was observed from 12 h onwards. Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells (P<0.05) was observed. High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells, but not in 5-FU-treated HT-29 cells (P<0.05). It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells, with these actions possibly mediated by JNK and P38 MAPK.

Hydroxychavicol sensitizes imatinib-resistant chronic myelogenous leukemia cells to TRAIL-induced apoptosis by ROS-mediated IAP downregulation

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of cytokine superfamily, induces apoptosis in a number of tumor cells through the activation of extrinsic apoptotic pathway but shows little or no cytotoxicity toward normal cells. However some tumor cells are inherently resistant to TRAIL-mediated apoptosis, which needs to be addressed to establish TRAIL as a potential chemotherapeutic drug. In this study, our aim was to manipulate TRAIL-apoptosis pathway by hydroxychavicol (HCH), a polyphenol from Piper betel leaf, for the induction of apoptosis in TRAIL resistant chronic myeloid leukemia cell. When imatinib-resistant K562 cells were treated with HCH, it made these K562 cells sensitive to TRAIL. It was observed that HCH downregulated antiapoptotic proteins XIAP and FLIP, whereas the expression of TRAIL receptors, DR4 and DR5, remains unchanged. Moreover, we observed that reactive oxygen species or ROS played a crucial role in the downregulation of FLIP and XIAP because ROS scavenger significantly reversed the decrease of XIAP, and FLIP. Ubiquitin-proteasome pathway was observed to play a crucial role in the downregulation of XIAP and FLIP, as proteasomal inhibitor MG132 significantly reversed the downregulation of XIAP and FLIP. In conclusion, this study demonstrates the combinatorial treatment of TRAIL and HCH as promising alternative therapeutic approach to treat the imatinib-resistant leukemia, which are also resistant to TRAIL.

Potential Allylpyrocatechol Derivatives as Antibacterial Agent Against Oral Pathogen of S. sanguinis ATCC 10,556 and as Inhibitor of MurA Enzymes: in vitro and in silico Study

BACKGROUND

Streptococcus sanguinis is Gram-positive bacteria that contribute to caries. Many antibacterial agents are resistant against bacteria so that the discovery of new antibacterial agents is a crucial issue. Mechanism of antibacterial agents by disrupting cell wall bacteria is a promising target to be developed. One of the enzymes contributing to the cell wall is MurA enzyme. MurA is an enzyme catalyzing the first step of peptidoglycan biosynthesis in the cell wall formation. Inhibiting MurA is an effective and efficient way to kill the bacteria. Source of bioactive compounds including the antibacterial agent can be found in natural product such as herbal plant. Piper betle L. was reported to contain active antibacterial compounds. However, there is no more information on the antibacterial activity and molecular mechanism of P. betle's compound against S. sanguinis.

PURPOSE

The study aims to identify antibacterial constituents of P. betle L. and evaluate their activities through two different methods including in vitro and in silico analysis.

MATERIALS AND METHODS

The antibacterial agent was purified by bioactivity-guided isolation with combination chromatography methods and the chemical structure was determined by spectroscopic methods. The in vitro antibacterial activity was evaluated by disc diffusion and dilution methods while the in silico study of a compound binds on the MurA was determined using PyRx program.

RESULTS

The antibacterial compound identified as allylpyrocatechol showed inhibitory activity against S. sanguinis with an inhibition zone of 11.85 mm at 1%, together with MIC and MBC values of 39.1 and 78.1 μg/mL, respectively. Prediction for molecular inhibition mechanism of allylpyrocatechols against the MurA presented two allylpyrocatechol derivatives showing binding activity of -5.4, stronger than fosfomycin as a reference with the binding activity of -4.6.

CONCLUSION

Two allylpyrocatechol derivatives were predicted to have a good potency as a novel natural antibacterial agent against S. sanguinis through blocking MurA activity that causes disruption of bacterial cell wall.

Caffeates and Caffeamides: Synthetic Methodologies and Their Antioxidant Properties

Polyphenols are secondary metabolites of plants and include a variety of chemical structures, from simple molecules such as phenolic acids to condensed tannins and highly polymerized compounds. Caffeic acid (3,4-dihydroxycinnamic acid) is one of the hydroxycinnamate metabolites more widely distributed in plant tissues. It is present in many food sources, including coffee drinks, blueberries, apples, and cider, and also in several medications of popular use, mainly those based on propolis. Its derivatives are also known to possess anti-inflammatory, antioxidant, antitumor, and antibacterial activities, and can contribute to the prevention of atherosclerosis and other cardiovascular diseases. This review is an overview of the available information about the chemical synthesis and antioxidant activity of caffeic acid derivatives. Considering the relevance of these compounds in human health, many of them have been the focus of reviews, taking as a center their obtaining from the plants. There are few revisions that compile the chemical synthesis methods, in this way, we consider that this review does an important contribution.

Relationship of oxidative stress in the resistance to imatinib in Tunisian patients with chronic myeloid leukemia: A retrospective study

Background

This work aimed to evaluate oxidative stress in chronic myeloid leukemia (CML) patients treated with tunisian (IM) vs controls and in CML patients with resistance to IM vs patients without resistance to IM.

Methods

The study included 40 CML patients and 34 controls. Of 40 patients with CML, 26 patients were developed in resistance to IM. The oxidant/antioxidant markers were evaluated by spectrophotometric methods for all used samples.

Results

For CML patients, increased malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels were found compared to controls (P < .001; P = .01). Higher catalase (CAT) activity (P = .048) and lower superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, reduced Glutathione (GSH) and vitamin C levels were found in CML patients (P < .001). The comparison between the resistant vs no‐resistant CML patients revealed higher MDA level (P = .02) and CAT and SOD activities in IM‐resistant patients (P = .04, P = .03). GPx activity was reduced (P = .04). Furthermore, increased mean ratio of MDA/GSH, MDA/GPx, and SOD/(GPx + CAT) was found in IM‐resistant patients as compared with no‐resistant (P = .01, P = .01, P = .035). The mean ratio of GPx/GSH in the IM‐resistant CML patients was lower than in IM no‐resistant one (P = .039). For IM‐resistant patients, we found negative correlation between MDA level and the ratio SOD/(CAT + GPx) (r = −0.46, P = .002); and positive correlation between SOD and (CAT + GPx) activities (r = 0.38, P = .06) and between GSH level and GPx activity (r = 0.53, P = .01).

Conclusions

Our results have shown a highly disturbed oxidative profile in IM‐resistant CML patients as compared to no‐resistant. The H₂O₂ has a key role in the resistance to IM treatment.

Phytochemical composition, β-glucuronidase inhibition, and antioxidant properties of two fractions of Piper betle leaf aqueous extract

RATIONALE

Piper betle leaf, used as masticatory in South Asia, is also medicinally important.

OBJECTIVE

This work was done to analyze phytochemical composition of two solvent fractions (chloroform and ethyl acetate) of the aqueous extracts obtained from eight varieties of P. betle leaves and to identify the active components against β-glucuronidase by chemometric analysis.

RESULTS

Twenty-four phenolic compounds, in addition to different organic acids, fatty acids, amino acids, sugars, and polyols, were identified from the solvent fractions. The extracts inhibited the enzyme β-glucuronidase. Piceatannol was the most active constituent against the enzyme (activity 12 times higher than that of silymarin), Chlorogenic acid also inhibited β-glucuronidase (activity 4.4 times higher when compared to silymarin). 2,2'-Diphenyl-1-picrylhydrazyl and superoxide free radical scavenging activities of both the fractions of eight varieties of P. betle leaf extracts showed very strong antioxidant potentiality.

CONCLUSION

The findings validated some medicinal properties of the said leaves.

PRACTICAL APPLICATIONS

Edible leaves of Piper betle are medicinally and economically important. Leaves of different local varieties are reported to be used for the treatment of different diseases. The leaves have many biological properties, hepatoprotection being one of them. A large number of rural population is economically dependent on the cultivation of betel vine. But with a rapid change in lifestyle, the chewing habit of P. betle is decreasing ultimately affecting the livelihood of farmers dependent on betel cultivation. Knowledge on β-glucuronidase inhibitory activity and the mechanism for hepatoprotection of different P. betle varieties may validate the medicinal properties of betel, which would increase consumption of these leaves.

Hydroxychavicol from Piper betle induces apoptosis, cell cycle arrest, and inhibits epithelial-mesenchymal transition in pancreatic cancer cells

Pancreatic cancer is a major cause of cancer-related mortality around the world. Currently, options for diagnosis and treatment are extremely limited, which culminates in a very high mortality rate. Intensive research spanning more than four decades has met several roadblocks in terms of improvement in overall survival. In this study, we have evaluated the effect of Hydroxychavicol (HC), a naturally occurring and abundantly isolatable allylarene from Piper betle leaves on pancreatic cancer cells. Our investigation reveals that HC inhibits proliferation and epithelial-mesenchymal transition (EMT) in pancreatic cancer cells. HC induces DNA damage, as evidenced by γ-H2AX, 53BP1 induction and comet assay, which further results in mitotic catastrophe and apoptosis. The apoptosis induced by HC is JNK pathway-dependent and caspase-mediated. HC also inhibits migration and invasion of pancreatic cancer cells via a generalized repression of genes involved in EMT. A quantitative real time PCR-based array revealed at least 14 different genes to be differentially expressed upon HC treatment in pancreatic cancer cells. These results show significant potential of HC as an anticancer agent against pancreatic cancer.

Effects of Piper betle fractionated extracts on inhibition of Streptococcus mutans and Streptococcus intermedius

The overgrowth of certain strains of normal flora in oral cavity can cause many kinds of oral infections or diseases such as carries, periodontitis, and gingivitis. Prevention and treatment of these diseases are usually achieved by chemical antiseptics. However, these chemicals are found as negative impacts of human health hazards and accession of microbial resistance. The present study explores the potential of Piper betle extracts on inhibition of two oral pathogenic bacteria; Streptococcus mutans DMST 41283 and Streptococcus intermedius DMST 42700. P. betle demonstrated significantly higher inhibitory activity against both pathogenic strains than Acacia catechu, Camellia sinensis, Coccinia grandis, Solanum indicum, and Streblus asper. Among fractionated extracts of P. betle from several solvents, the extract from ethyl acetate (Pb-EtOAc) possessed the widest inhibition zone of 11.0 ± 0.1 and 11.3 ± 0.4 mm against both bacterial strains, respectively. Pb-EtOAc showed the same minimum inhibitory concentration of 0.5 mg/mL against both strains, whereas its minimum bactericidal concentrations were 2.0 and 0.5 mg/mL against S. mutans and S. intermedius, respectively. HPLC analysis demonstrated that the major active compound of Pb-EtOAc was 4-allylpyrocatechol. It was found that the killing kinetics of Pb-EtOAc against both test strains were time and dose dependent. Scanning electron microscopy micrographs showed the morphological changes and depletion of the tested pathogens indicating cell destruction after exposure to Pb-EtOAc. It is confirmed that Pb-EtOAc is potentially effective against both oral pathogens and might be used as natural alternative agents in prevention and treatment of oral infections caused by oral pathogenic bacteria.

KLF5 controls glutathione metabolism to suppress p190-BCR-ABL+ B-cell lymphoblastic leukemia

High-risk B-cell acute lymphoblastic leukemia (B-ALL) remains a therapeutic challenge despite advances in the use of tyrosine kinase inhibitors and chimeric-antigen-receptor engineered T cells. Lymphoblastic-leukemia precursors are highly sensitive to oxidative stress. KLF5 is a member of the Krüppel-like family of transcription factors. KLF5 expression is repressed in B-ALL, including BCR-ABL1+ B-ALL. Here, we demonstrate that forced expression of KLF5 in B-ALL cells bypasses the imatinib resistance which is not associated with mutations of BCR-ABL. Expression of Klf5 impaired leukemogenic activity of BCR-ABL1+ B-cell precursors in vitro and in vivo. The complete genetic loss of Klf5 reduced oxidative stress, increased regeneration of reduced glutathione and decreased apoptosis of leukemic precursors. Klf5 regulation of glutathione levels was mediated by its regulation of glutathione-S-transferase Mu 1 (Gstm1), an important regulator of glutathione-mediated detoxification and protein glutathionylation. Expression of Klf5 or the direct Klf5 target gene Gstm1 inhibited clonogenic activity of Klf5^∆/∆ leukemic B-cell precursors and unveiled a Klf5-dependent regulatory loop in glutamine-dependent glutathione metabolism. In summary, we describe a novel mechanism of Klf5 B-ALL suppressor activity through its direct role on the metabolism of antioxidant glutathione levels, a crucial positive regulator of leukemic precursor survival.

Ameliorating effect of Kalpaamruthaa on altered energy metabolism in BCR-ABL+ cell line induced leukemic mouse model

OBJECTIVE

To evaluate the protective effect of Kalpaamruthaa (KA), a modified Siddha preparation, in BCR-ABL+ leukemic mouse model.

METHODS

BCR-ABL leukemia was induced in 6-10-week-old female BALB/c mice by a single tail vein injection of the 12B1 cell line. Leukemia-induced animals were treated with KA at a dosage of 200 mg/kg body weight dissolved in 0.5 mL of olive oil for 14 days by gastrogavage. Imatinib mesylate was used as the control drug. Glycolytic, gluconeogenic, mitochondrial, tricarboxylic acid cycle and respiratory chain enzymes in the spleen and liver of mouse were compared between the control and experiment groups by biochemical assays.

RESULTS

Leukemia-bearing mice showed a significant increase in glycolytic enzymes and a signififi cant decrease in gluconeogenic enzymes, tricarboxylic acid cycle and respiratory chain enzymes as compared with control animals. Treatment with KA signififi cantly reversed the changes seen in the levels of the glycolytic enzymes, gluconeogenic enzymes and mitochondrial enzymes.

CONCLUSION

The presence of various flfl avonoids and polyphenols in the drug KA might have resulted in the amelioration of altered glucose metabolism resulting in the regression of leukemia.

Comparison of Dasatinib, Nilotinib, and Imatinib in the Treatment of Chronic Myeloid Leukemia

To overcome the drug resistance phenomenon induced by Imatibib (IM), in clinical practice, are often used second generation of tyrosine kinase inhibitors as Nilotinib (NIL); a such potent inhibitor of the BCR/ABL kinase and Dasatinib (DAS), a inhibitor of BCR/ABL kinase, and inhibitor SrC family kinase. In this study we evaluated the in vivo effect of DAS, NIL, and IM on intracellular calcium concentration, oxidative stress, and apoptosis in peripheral blood leukocytes of 45 newly diagnosed patients with chronic myeloid leukaemia (CML-PBM). Our data demonstrated that treatment with DAS and NIL showed an higher modulating potential than IM on intracellular calcium concentration by inhibiting the thapsigargin, a sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor, and Lithium (Li) an inositol 1,4,5-triphosphate (InsP3) receptor inhibitor activities. Moreover our data demonstrated that NIL and DAS have significantly increased apoptosis more than IM by involving both intracellular calcium signaling as well as oxidative stress. The acquisition of the oxidative stress and calcium channels receptors values data could help the hematologist to modulate and improve the treatment of chronic myeloid leukaemia (CML) pathology.

The variable chemotherapeutic response of Malabaricone-A in leukemic and solid tumor cell lines depends on the degree of redox imbalance

PURPOSE

The 'two-faced' character of reactive oxygen species (ROS) plays an important role in cancer biology by acting as secondary messengers in intracellular signaling cascades, enhancing cell proliferation and survival, thereby sustaining the oncogenic phenotype. Conversely, enhanced generation of ROS can trigger an oxidative assault leading to a redox imbalance translating into an apoptotic cell death. Intrinsically, cancer cells have higher basal levels of ROS which if supplemented by additional oxidative insult by pro-oxidants can be cytotoxic, an example being Malabaricone-A (MAL-A). MAL-A is a plant derived diarylnonanoid, purified from fruit rind of the plant Myristica malabarica whose anti-cancer activity has been demonstrated in leukemic cell lines, the modality of cell death being apoptosis. This study aimed to compare the degree of effectiveness of MAL-A in leukemic vs. solid tumor cell lines.

METHODS

The cytotoxicity of MAL-A was evaluated by the MTS-PMS cell viability assay in leukemic cell lines (MOLT3, K562 and HL-60) and compared with solid tumor cell lines (MCF7, A549 and HepG2); further studies then proceeded with MOLT3 vs. MCF7 and A549. The contribution of redox imbalance in MAL-A induced cytotoxicity was confirmed by pre-incubating cells with an antioxidant, N-acetyl-L-cysteine (NAC) or a thiol depletor, buthionine sulfoximine (BSO). MAL-A induced redox imbalance was quantitated by flow cytometry, by measuring the generation of ROS and levels of non protein thiols using dichlorofluorescein diacetate (CM-H2DCFDA) and 5-chloromethylfluorescein diacetate (CMFDA) respectively. The activities of glutathione peroxidase (GPx), superoxide dismutase, catalase (CAT), NAD(P)H dehydrogenase (quinone 1) NQO1 and glutathione-S-transferase GST were measured spectrophotometrically. The mitochondrial involvement of MAL-A induced cell death was measured by evaluation of cardiolipin peroxidation using 10-N-nonyl acridine orange (NAO), transition pore activity with calcein-AM, while the mitochondrial transmembrane electrochemical gradient (∆ψ(m)) was measured by JC-1, fluorescence being acquired in a flow cytometer. The apoptotic mode of cell death was evaluated by double staining with annexin V-FITC and propidium iodide (PI), cell cycle analysis by flow cytometry and caspase-3 activity spectrophotometrically. The expression of Nrf2 and HO-1 was examined by western blotting.

RESULTS

MAL-A demonstrated a higher degree of cytotoxicity in three leukemic cell lines whose IC50 ranged from 12.70 ± 0.10 to 18.10 ± 0.95 µg/ml, whereas in three solid tumor cell lines, the IC50 ranged from 28.10 ± 0.58 to 55.26 ± 5.90 µg/ml. This higher degree of cytotoxicity in MOLT3, a leukemic cell line was due to a higher induction of redox imbalance, evident by both an increased generation of ROS and concomitant depletion of thiols. This was confirmed by pre-incubation with NAC and BSO, wherein NAC decreased MAL-A induced cytotoxicity by 2.04 fold while BSO enhanced MAL-A cytotoxicity and decreased the IC50 by 5.60 fold. However, in solid tumor cell lines (MCF7 and A549), NAC minimally decreased MAL-A induced cytotoxicity, and BSO increased the IC50 by 1.96 and 2.39 fold respectively. Furthermore, the generation of ROS by MAL-A increased maximally in MOLT3 as the fluorescence increased from 44.28 ± 7.85 to 273.99 ± 32.78, and to a lesser degree in solid tumor cell lines, MCF7 (44.28 ± 14.89 to 207.97 ± 70.64) and A549 (37.87 ± 3.24 to 147.12 ± 38.53). In all three cell lines there was a concomitant depletion of thiols as in MOLT3, the GMFC decreased from 340.65 ± 60.39 to 62.67 ± 11.32, in MCF7 (277.82 ± 50.32 to 100.39 ± 31.93) and in A549 (274.05 ± 59.13 to 83.15 ± 21.43). In MOLT3 as compared to MCF7 and A549, decrease in the activities of GPx, CAT, NQO1 and GST was substantially greater. In all cell lines, the MAL-A induced redox imbalance translated into triggering of initial mitochondrial apoptotic events. Here again, MAL-A induced a higher degree of cardiolipin peroxidation in MOLT3 (67.01%) than MCF7 and A549 (29.15% and 44.30%), as also down regulated the mitochondrial transition pore activity from baseline to a higher extent, GMFC being 48.05 ± 2.37 to 10.70 ± 3.97 (MOLT3), 43.55 ± 3.36 to 15.36 ± 0.60 (MCF7) and 39.58 ± 0.4 to 12.65 ± 1.56 (A549). Perturbation of mitochondrial membrane potential evident by a decrease in the ratio of red/green (J-aggregates/monomers) was 134 fold (14.73/0.11) in MOLT3, 45 fold in MCF7 (20.72/0.46) and 34 fold in A549 (22.01/0.64). The extent of apoptosis using a similar concentration of MAL-A was maximal in MOLT3, wherein a 105 fold increase in annexin V binding was evident (0.83 ± 0.51 to 87.08 ± 9.85%) whereas it increased by 43.11 fold in MCF7 (0.69 ± 0.30 to 29.75 ± 11.79%) and 47.52 fold in A549 (0.61 ± 0.31 to 28.99 ± 17.21%). MAL-A induced apoptosis was also associated with a higher degree of caspase-3 activity in MOLT3 vs. MCF7 or A549 which translated into halting of cell cycle progression, evident by an increment in the sub-G0/G1 population [19.26 fold in MOLT3 (0.95 ± 0.45 vs. 18.30 ± 1.90%), 11.01 fold in MCF7 (0.97 ± 0.37 vs. 10.68 ± 0.69%) and 8.58 fold in A549 (1.06 ± 0.45 vs. 9.10 ± 1.05%)]. MAL-A effectively inhibited Nrf2 and HO-1, more prominently in MOLT3. Furthermore, the decreased expression of Nrf2 in MOLT3 correlated with the decreased activities of NQO1 and GST, suggesting that targeting of the Nrf2 anti-oxidant pathway could be considered.

CONCLUSION

Taken together, MAL-A a pro-oxidant compound is likely to be more effective in leukemias, meriting further pharmacological consideration.

Ethnobotanical study of Loloh: Traditional herbal drinks from Bali (Indonesia)

ETHNOPHARMACOLOGICAL RELEVANCE

Loloh are herbal drinks produced and consumed exclusively in Bali (Indonesia) to prevent and treat different ailments. This is the first study to document plants species used as Loloh, reporting the phytochemical components and pharmacological properties of the most cited plants. Documenting the plants used in herbal drinks in Bali by local communities to treat various ailments (providing some information on phytochemistry and pharmacology of the most interesting plants).

MATERIALS AND METHODS

Ethnobotanical data were obtained through semi-structured interviews (individual and group discussions) and questionnaires. Plant specimens were collected, identified and made into herbarium vouchers.

RESULTS

A total of 51 plants species (belonging to 32 families) have been documented for their use in the various preparation of Loloh. Different plants and plant parts are used to prepare Loloh to treat heartburn, fever, diarrhea, hypertension, aphthous stomatitis (canker sores), and other minor health problems. These plants are mainly prepared as decoctions, are juiced or simply added to the preparation. The most cited plants (>30 informants) are Alstonia scholaris (L.) R. Br., Blumea balsamifera (L.) DC., Cinnamomum burmanni Nees ex Bl., and Piper betle L. These plants are well studied with multiple demonstrated pharmacological activities (e.g., antimicrobial, anticancer, antidiabetic).

CONCLUSION

The Balinese communities still preserve a rich ethnobotanical knowledge. Several species are well known for their pharmacological properties, but some [such as Pneumatopteris callosa (Blume) Nakai and Dendrocnide stimulans (L. f.) Chew] are understudied and could be promising candidates for further research.

Piper betle leaf extract enhances the cytotoxicity effect of 5-fluorouracil in inhibiting the growth of HT29 and HCT116 colon cancer cells

OBJECTIVE

The combination effect of Piper betle (PB) and 5-fluorouracil (5-FU) in enhancing the cytotoxic potential of 5-FU in inhibiting the growth of colon cancer cells was investigated.

METHODS

HT29 and HCT116 cells were subjected to 5-FU or PB treatment. 5-FU and PB were then combined and their effects on both cell lines were observed after 24 h of treatment. PB-5-FU interaction was elucidated by isobologram analysis. Apoptosis features of the treated cells were revealed by annexin V/PI stain. High-performance liquid chromatography (HPLC) was performed to exclude any possible chemical interaction between the compounds.

RESULTS

In the presence of PB extract, the cytotoxicity of 5-FU was observed at a lower dose (IC50 12.5 µmol/L) and a shorter time (24 h) in both cell lines. Both cell lines treated with 5-FU or PB alone induced a greater apoptosis effect compared with the combination treatment. Isobologram analysis indicated that PB and 5-FU interacted synergistically and antagonistically in inhibiting the growth of HT29 and HCT116 cells, respectively.

CONCLUSIONS

In the presence of PB, a lower dosage of 5-FU is required to achieve the maximum drug effect in inhibiting the growth of HT29 cells. However, PB did not significantly reduce 5-FU dosage in HCT116 cells. Our result showed that this interaction may not solely contribute to the apoptosis pathway.

Combination of imatinib and clotrimazole enhances cell growth inhibition in T47D breast cancer cells

Imatinib mesylate (IM), a tyrosine kinase inhibitor, is used as targeted cancer therapy. However, mono-targeting by IM does not always achieve full tumor eradication and thus it is recommended to combine IM with other anticancer agents. Clotrimazole (CLT) is an antifungal azole derivative with promising anticancer effects due to inhibiting the activity of glycolytic enzymes. The present study aimed to evaluate the effect of combining CLT with IM on breast cancer cell line in an attempt to establish effective new combination. T47D human breast cancer cell line was treated with different concentrations of IM and/or CLT for 48 h. IM-CLT interaction was determined by isobologram equation and combination index. Cell viability was confirmed by measuring LDH activity. As indicators of glycolysis inhibition, the expression of hexokinase-2 (HK-2) and 6-phosphofructo-1-kinase (PFK-1) plus the activity of intracellular lactate dehydrogenase (LDH) and pyruvate kinase (PK) were determined. In addition, glucose consumption and adenosine triphosphate (ATP) production were measured. Moreover, nitric oxide (NO), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-α (HIF-α) were also determined as they are modulators for glycolysis. This study demonstrated that IM or CLT synergistically inhibited cell growth in T47D as shown by combination and dose reduction indices. The combination of 15 μM IM and 20 μM CLT significantly decreased glucose consumption, activity of both PK and intracellular LDH, while increased leaked LDH, VEGF and NO in the medium compared to each drug alone. Furthermore the combination decreased gene expression of HK-2, PFK-1 and ATP content compared to the control. In conclusion, the synergistic effect of CLT on IM cytotoxicity in T47D cell line maybe mediated through inhibition of glycolysis and increasing both NO and VEGF. Further studies are required to confirm the efficiency and safety of this combination.

STI571 protects neuronal cells from neurotoxic prion protein fragment-induced apoptosis

Prion diseases are neurodegenerative disorders caused by the accumulation of misfolded prion proteins [scrapie form of PrP (PrP(Sc))]. PrP(Sc) accumulation in the brain causes neurotoxicity by inducing mitochondrial-apoptotic pathways. Neurodegeneration can be prevented by imatinib mesylate (Gleevec or STI571) that regulates c-Abl tyrosine kinases, which elicit protective effects in neurodegenerative disease models. However, the protective effect of STI571 against prion disease remains unknown. In the present study, the effect of STI571 on prion peptide-induced neuronal death was investigated. Results showed that STI571 rescued neurons from PrP106-126-induced neurotoxicity by preventing mitochondrial dysfunction. STI571-inhibited c-Abl tyrosine kinases prevented PrP106-126-induced reduction in mitochondrial potential, Bax translocation to the mitochondria and cytochrome c release. The protective effect of STI571 against mitochondrial dysfunction was related to the activation of BIM expression. This study is the first to demonstrate the protective effect of STI571 against prion-mediated neurotoxicity. Our results suggested that imatinib mesylate treatment may be a novel therapeutic strategy to treat prion-mediated neurotoxicity.

Superoxide activates mTOR-eIF4E-Bax route to induce enhanced apoptosis in leukemic cells

Mammalian target of rapamycin (mTOR) is a central kinase that regulates cell survival, proliferation and translation. Reactive oxygen species (ROS) are second messengers with potential in manipulating cellular signaling. Here we report that two ROS generating phytochemicals, hydroxychavicol and curcumin synergize in leukemic cells in inducing enhanced apoptosis by independently activating both mitogen activated protein kinase (MAPK) (JNK and P(38)) and mTOR pathways. Low level transient ROS generated after co-treatment with these phytochemicals led to activation of these two pathways. Both mTOR and MAPK pathways played important roles in co-treatment-induced apoptosis, by knocking down either mTOR or MAPKs inhibited apoptosis. Activation of mTOR, as evident from phosphorylation of its downstream effector eukaryotic translation initiation factor 4E-binding protein 1, led to release of eukaryotic translation initiation factor 4E (eIF4E) which was subsequently phosphorylated by JNK leading to translation of pro-apoptotic proteins Bax and Bad without affecting the expression of anti-apoptotic protein Bcl-xl. Our data suggest that mTOR and MAPK pathways converge at eIF4E in co-treatment-induced enhanced apoptosis and provide mechanistic insight for the role of mTOR activation in apoptosis.

Piper betle leaves: profiling phenolic compounds by HPLC/DAD-ESI/MS(n) and anti-cholinesterase activity

INTRODUCTION

Piper betle L. is a widely distributed plant in the tropical and subtropical regions, its leaves being largely consumed as a masticator and mouth freshener.

OBJECTIVE

The purposes of this work were to characterise the phenolic profile of this species and to improve knowledge of its anti-cholinesterase properties.

METHODS

The phenolic composition of P. betle leaf aqueous and ethanol extracts was characterised by HPLC coupled with a diode-array detector and combined with electrospray ionisation tandem MS, and in vitro cholinesterase inhibitory capacity of both extracts was assessed by spectrophotometric microassays. The effect on neuronal cells (SH-SY5Y) viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction and lactate dehydrogenase leakage.

RESULTS

Twelve phenolic compounds, comprising a phenylpropanoid, five cinnamoyl and six flavonoids derivatives were identified in P. betle leaves. Hydroxychavicol was the major compound in both extracts; however, the aqueous extract presented a greater diversity of compounds. Both extracts showed strong activity against both acetyl- and butyrylcholinesterase, which can be due, at least partially, to the phenolic composition. Furthermore, the aqueous extract proved to be cytotoxic to human neuroblastoma cells at concentrations higher than 500 µg/mL.

CONCLUSION

The results suggest that the consumption of P. betle leaves as an infusion can have a positive impact in the prevention and treatment of neurodegenerative diseases. Apigenin and luteolin derivatives are reported for the first time in this species.

Gamma-tocotrienol and hydroxy-chavicol synergistically inhibits growth and induces apoptosis of human glioma cells

Background

Gamma-tocotrienol (GTT), an isomer of vitamin E and hydroxy-chavicol (HC), a major bioactive compound in Piper betle, has been reported to possess anti-carcinogenic properties by modulating different cellular signaling events. One possible strategy to overcome multi-drug resistance and high toxic doses of treatment is by applying combinational therapy especially using natural bioactives in cancer treatment.

Methods

In this study, we investigated the interaction of GTT and HC and its mode of cell death on glioma cell lines. GTT or HC alone and in combination were tested for cytotoxicity on glioma cell lines 1321N1 (Grade II), SW1783 (Grade III) and LN18 (Grade IV) by [3-(4,5-dimethylthiazol-2- yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)- 2H- tetrazolium, inner salt] MTS assay. The interactions of each combination were evaluated by using the combination index (CI) obtained from an isobologram.

Results

Individually, GTT or HC displayed mild growth inhibitory effects against glioma cancer cell lines at concentration values ranging from 42–100 μg/ml and 75–119 μg/ml respectively. However, the combination of sub-lethal doses of GTT + HC dramatically enhanced the inhibition of glioma cancer cell proliferation and exhibited a strong synergistic effect on 1321N1 with CI of 0.55, and CI = 0.54 for SW1783. While in LN18 cells, moderate synergistic interaction of GTT + HC was observed with CI value of 0.73. Exposure of grade II, III and IV cells to combined treatments for 24 hours led to increased apoptosis as determined by annexin-V FITC/PI staining and caspase-3 apoptosis assay, showing caspase-3 activation of 27%, 7.1% and 79% respectively.

Conclusion

In conclusion, combined treatments with sub-effective doses of GTT and HC resulted in synergistic inhibition of cell proliferation through the induction of apoptosis of human glioma cells in vitro.

Apoptosis of bladder transitional cell carcinoma T24 cells induced by adenovirus-mediated inducible nitric oxide synthase gene transfection

OBJECTIVES

To investigate the effects of adenovirus-mediated inducible nitric oxide synthase gene transfection on bladder transitional cell carcinoma T24 cells, and to provide novel insights and approaches to clinical therapies against bladder transitional cell carcinoma.

METHODS

Firstly, construct recombinant adenovirus vector pAd-iNOS of iNOS, followed by transfection of pAd-iNOS into HECK293 packaging cells. Thirdly, harvest recombinant adenovirus rAd-iNOS after amplification and purification procedures. Finally, transfect the recombinant adenovirus rAd-iNOS into human bladder carcinoma T24 cells and examine the effect of rAd-iNOS transfection on apoptosis of T24 and possible mechanism.

RESULTS

As shown by this study, the recombinant adenovirus rAd-iNOS was constructed successfully. The virus titer was 5.8×10(8) PFU/mL and recombinant was verified by PCR analysis. Transfection of adenovirus rAd-iNOS into T24 cells could induce secretion of high NO concentration, P53 protein expression up-regulation, as well as promotion of T24 cell apoptosis.

CONCLUSIONS

The transfection of human bladder carcinoma T24 cells from recombinant adenovirus rAd-iNOS was confirmed to induce intracellular iNOS over-expression, high production of NO, up-regulation of intracellular P53 expression and promotion of cell apoptosis.

Synergistic apoptosis of CML cells by buthionine sulfoximine and hydroxychavicol correlates with activation of AIF and GSH-ROS-JNK-ERK-iNOS pathway

Background

Hydroxychavicol (HCH), a constituent of Piper betle leaf has been reported to exert anti-leukemic activity through induction of reactive oxygen species (ROS). The aim of the study is to optimize the oxidative stress –induced chronic myeloid leukemic (CML) cell death by combining glutathione synthesis inhibitor, buthionine sulfoximine (BSO) with HCH and studying the underlying mechanism.

Materials and Methods

Anti-proliferative activity of BSO and HCH alone or in combination against a number of leukemic (K562, KCL22, KU812, U937, Molt4), non-leukemic (A549, MIA-PaCa2, PC-3, HepG2) cancer cell lines and normal cell lines (NIH3T3, Vero) was measured by MTT assay. Apoptotic activity in CML cell line K562 was detected by flow cytometry (FCM) after staining with annexinV-FITC/propidium iodide (PI), detection of reduced mitochondrial membrane potential after staining with JC-1, cleavage of caspase- 3 and poly (ADP)-ribose polymerase proteins by western blot analysis and translocation of apoptosis inducing factor (AIF) by confocal microscopy. Intracellular reduced glutathione (GSH) was measured by colorimetric assay using GSH assay kit. 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA) and 4-amino-5-methylamino-2′,7′-difluorofluorescein (DAF-FM) were used as probes to measure intracellular increase in ROS and nitric oxide (NO) levels respectively. Multiple techniques like siRNA transfection and pharmacological inhibition were used to understand the mechanisms of action.

Results

Non-apoptotic concentrations of BSO significantly potentiated HCH-induced apoptosis in K562 cells. BSO potentiated apoptosis-inducing activity of HCH in CML cells by caspase-dependent as well as caspase-independent but apoptosis inducing factor (AIF)-dependent manner. Enhanced depletion of intracellular GSH induced by combined treatment correlated with induction of ROS. Activation of ROS- dependent JNK played a crucial role in ERK1/2 activation which subsequently induced the expression of inducible nitric oxide synthase (iNOS). iNOS- mediated production of NO was identified as an effector molecule causing apoptosis of CML cells.

Conclusion/Significance

BSO synergizes with HCH in inducing apoptosis of CML cells through the GSH-ROS-JNK-ERK-iNOS pathway.

Piper betel leaf extract: anticancer benefits and bio-guided fractionation to identify active principles for prostate cancer management

Plant extracts, a concoction of bioactive non-nutrient phytochemicals, have long served as the most significant source of new leads for anticancer drug development. Explored for their unique medicinal properties, the leaves of Piper betel, an evergreen perennial vine, are a reservoir of phenolics with antimutagenic, antitumor and antioxidant activities. Here, we show that oral feeding of betel leaf extract (BLE) significantly inhibited the growth of human prostate xenografts implanted in nude mice compared with vehicle-fed controls. To gain insights into the 'active principles', we performed a bioactivity-guided fractionation of methanolic BLE employing solvents of different polarity strengths using classical column chromatography. This approach yielded 15 fractions, which were then pooled to 10 using similar retention factors on thin-layer chromatographs. Bioactivity assays demonstrated that one fraction in particular, F2, displayed a 3-fold better in vitro efficacy to inhibit proliferation of prostate cancer cells than the parent BLE. The presence of phenols, hydroxychavicol (HC) and chavibetol (CHV), was confirmed in F2 by nuclear magnetic resonance, high-performance liquid chromatography and mass spectroscopy. Further, the HC containing F2 subfraction was found to be ~8-fold more potent than the F2 subfraction that contained CHV, in human prostate cancer PC-3 cells as evaluated by the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay. Removing CHV from F2 remarkably decreased the IC50 of this fraction, indicating that HC is perhaps the major bioactive constituent, which is present to an extent of 26.59% in BLE. These data provide evidence that HC is a potential candidate for prostate cancer management and warrants further preclinical evaluation.

ICB3E induces iNOS expression by ROS-dependent JNK and ERK activation for apoptosis of leukemic cells

The role of c-Jun N terminal Kinase (JNK) has been well documented in various cellular stresses where it leads to cell death. Similarly, extracellular signal-regulated kinase (ERK) which was identified as a signalling molecule for survival pathway has been shown recently to be involved in apoptosis also. Recently we reported that ICB3E, a synthetic analogue of Piper betle leaf-derived apoptosis-inducing agent hydroxychavicol (HCH), possesses anti-chronic myeloid leukemia (CML) acitivity in vitro and in vivo without insight on mechanism of action. Here we report that ICB3E is three to four times more potent than HCH in inducing apoptosis of leukemic cells without having appreciable effects on normal human peripheral blood mononuclear cells, mouse fibroblast cell line NIH3T3 and monkey kidney epithelial cell line Vero. ICB3E causes early accumulation of mitochondria-derived reactive oxygen species (ROS) in K562 cells. Unlike HCH, ICB3E treatment caused ROS dependent activation of both JNK, ERK and induced the expression of iNOS leading to generation of nitric oxide (NO). This causes cleavage of caspase 9, 3 and PARP leading to apoptosis. Lack of cleavage of caspase 8 and inability of blocking chimera antibody to DR5 or neutralizing antibody to Fas to reverse ICB3E-mediated apoptosis suggest the involvement of only intrinsic pathway. Our data reveal a novel ROS-dependent JNK/ERK-mediated iNOS activation pathway which leads to NO mediated cell death by ICB3E.