The role of oxidative stress in anticancer activity of sesquiterpene lactones

Brevilin A promotes oxidative stress and induces mitochondrial apoptosis in U87 glioblastoma cells

Background

Sesquiterpene lactones are plant-derived, natural, bioactive molecules often used against inflammatory diseases in traditional Chinese medicines. Recently, sesquiterpene lactones have been reported to exhibit potent anticancer activity. In the present study, we have investigated the anticancer activity of Brevilin A, a sesquiterpene lactone component of Centipeda minima, against U87 glioblastoma cells.

Materials and methods

The cell proliferation was determined by MTT assay. Cell morphological changes were observed by phase-contrast microscopy. Flow cytometry was used to measure apoptosis. Glutathione (GSH), ROS generation, and mitochondrial membrane potential were measured using commercially available kits. The expression of proteins was measured by Western blotting analysis.

Results

Brevilin A inhibited the proliferation of, and induced severe morphological changes and apoptotic cell death in, U87 glioblastoma cells in a dose-dependent manner. Further mechanistic study revealed that Brevilin A induces oxidative stress, as evident from ROS generation, GSH depletion, and increased phosphorylation of stress-activated proteins p38 and JNK. Furthermore, Brevilin A bcl-xl/bak ratio, decreased mitochondrial membrane potential and induced cytochrome c release from mitochondria into cytosol in a dose-dependent manner. Finally, Brevilin A decreased the expression of Xiap and increased the expression of cleaved forms of caspase-9 and -3 and PARP in a dose-dependent manner.

Conclusion

Collective findings demonstrated that Brevilin A is a potent, anticancer, bioactive molecule and it effectively induces apoptosis in U87 glioblastoma cells, which is associated with induction of oxidative stress and mitochondrial dysfunction.

Application of sesquiterpene lactone: A new promising way for cancer therapy based on anticancer activity

Cancer is one of the most dangerous diseases that are rapidly increasing globally. After heart disease, it is the second leading cause of death, accounting for seven million deaths each year. Chemotherapy is the use of cytotoxic drugs on cancer cells. But the use of common chemotherapy drugs poses a problem due their high side effects and low efficacy. As a result, efforts are on to find new potent compounds with low side effects. The compounds extracted from plants have been studied in this regard due to their prevalence. Sesquiterpene lactones are a group of natural compounds that were first detected in Asteraceae dark plants. These compounds exercise their effects by reacting with functional groups available on proteins and enzymes, especially the thiol group. Owing to the high side effects as an antitumor synthetic drugs, efforts are being made to find drugs with high efficiency and low side effects. Their high structural ranges have attracted the attention of many researchers as a potential source of new anticancer drugs.

Zatariamultiflora ameliorates cisplatin-induced testicular damage via suppression of oxidative stress and apoptosis in a mice model

Objectives

Cisplatin (CP), as an anti-neoplastic drug, causes testicular damage. Zataria multiflora Boiss (ZM), a medicinal plant, has antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effects of ZM against CP-induced testicular toxicity.

Materials and Methods

In this experimental study, thirty-two adult male mice were randomly divided into four groups. The control group received normal saline with oral gavage during 7 days; ZM group received ZM (200 mg/kg) during 7 days by gavage; CP group received CP (10 mg/kg) intraperitoneally (IP) in the 5^th day of study; ZM + CP group received ZM during 7 days and CP was injected in 5th day. Sperm parameters, biochemical (MDA, GSH, and PC) levels, serum testosterone levels, and histopathological and immunohistochemical assays of testis were examined one day after the last drug treatment.

Results

CP treatment caused significant damage via changed sperm parameters (sperm motility, count, viability rate, and abnormalities), increased oxidative stress (increased MDA and PC levels, and decreased GSH level), histological changes (degeneration, necrosis, arrest of spermatogenesis, congestion, and decrease in thickness of the germinal epithelium, diameter of seminiferous tubules, and Johnsen's Score), decreased serum testosterone level, and increased caspase-3 immunoreactivity. ZM preserved spermatogenesis and mitigated the toxic effects of CP on the testis tissue. In addition, treatment with ZM significantly reduced caspase-3 immunoreactivity.

Conclusion

The findings of this study suggest that ZM as a potential antioxidant compound and due to free radicals scavenging activities has a protective effect against CP-induced testicular toxicity.

Copper(I) oxide nanoparticles catalyzed click chemistry based synthesis of melampomagnolide B-triazole conjugates and their anti-cancer activities

A series of thirty one melampomagnolide B-triazole conjugates was synthesized via Copper(I) oxide nanoparticles catalyzed click chemistry. These conjugates were evaluated for their anti-cancer activities against a panel of five human cancer cell lines. The most active compound 6e showed high activity against HCT116 cell line with IC₅₀ value of 0.43 μM, which demonstrated 11.5-fold improvement compared to that of the parent compound melampomagnolide B (IC₅₀ = 4.93 μM). Compound 6e showed significant efficacy of inducing apoptosis, inhibiting proliferation and migration of HCT116 cells. The preliminary molecular mechanism of 6e was also investigated. On the base of these results, compound 6e might be considered as a promising candidate for further evaluation as a potential anti-cancer drug.

β-amyloid cytotoxicity is prevented by natural achillolide A

Alzheimer's disease (AD) is the most prevalent cause of dementia in adults. Current available drugs for AD transiently alleviate some of the symptoms, but do not modify the disease mechanism or cure it. Therefore, new drugs are desperately needed. Key contributors to AD are amyloid beta (Aβ)- and reactive oxygen species (ROS)-induced cytotoxicities. Plant-derived substances have been shown to affect various potential targets in various diseases including AD. Therefore, phytochemicals which can protect neuronal cells against these insults might help in preventing and treating this disease. In the following research, we have isolated the sesquiterpene lactone achillolide A from the plant Achillea fragrantissima and, for the first time, characterized its effects on Aβ-treated neuroblastoma cells. Aβ is a peptide derived from the sequential cleavage of amyloid precursor protein, and is part of the pathogenesis of AD. Our current study aimed to determine whether achillolide A can interfere with Aβ-induced processes in Neuro2a cells, and protect them from its toxicity. Our results show that achillolide A decreased Aβ-induced death and enhanced the viability of Neuro2a cells. In addition, achillolide A reduced the accumulation of Aβ-induced ROS and inhibited the phosphorylation of stress-activated protein kinase/c-Jun N-terminal kinase and p44/42 mitogen-activated protein kinase in these cells. We therefore suggest that achillolide A may have therapeutic potential for the treatment of AD.

15-Hydroxygermacranolides as Sources of Structural Diversity: Synthesis of Sesquiterpene Lactones by Cyclization and Rearrangement Reactions. Experimental and DFT Study

A study on the electrophile-induced rearrangement of two 15-hydroxygermacranolides, salonitenolide and artemisiifolin, was carried out. These compounds underwent electrophilic intramolecular cyclizations or acid-mediated rearrangements to give sesquiterpene lactones with different skeletons such as eudesmanolides, guaianolides, amorphanolides, or other germacranolides. The cyclization that gives guaianolides can be considered a biomimetic route to this type of sesquiterpene lactones. The use of acetone as a solvent changes the reactivity of the two starting germacranolides to the acid catalysts, with a 4,15-diol acetonide being the main product obtained. The δ-amorphenolide obtained by intramolecular cyclization of this acetonide is a valuable intermediate for accessing the antimalarials artemisinin and its derivatives. Mechanistic proposals for the transformations are raised, and to provide support them, quantum chemical calculations [DFT B3LYP/6-31+G(d,p) level] were undertaken.

Polygodial analog induces apoptosis in LNCaP prostate cancer cells

Prostate cancer (PCa) is the second leading cause of death in American men. The chemotherapeutic treatment strategies are generally not effective and can lead to side effects. Hence, there is an urgent need to identify novel chemotherapeutic agents. The aim of this study was to synthesize and evaluate the therapeutic effects of a synthetic analog of polygodial (PG), a pungent constituent abundantly present in mountain pepper, water pepper and dorrigo pepper, on LNCaP PCa cell line and its anti-cancer mechanisms in a preclinical study. We evaluated the anti-cancer potential of the PG analog namely DRP-27 using various assays such as cell viability by MTT assay, anchorage independent growth by soft agar assay, reactive oxygen species generation by 2',7'-dichlorofluorescein probe-based fluorescence assay, and apoptosis by Annexin-V and TUNEL assays respectively. Western blot analysis was performed to identify the molecular mechanism of DRP-27-induced cell death. Our results showed that DRP-27 significantly inhibited LNCaP cell proliferation in a dose-dependent manner at 48 h treatment in vitro. In addition, DRP-27 potently inhibited anchorage-independent growth of these cells. Flow cytometry, Annexin-V and TUNEL assays confirmed that DRP-27 induces apoptosis in LNCaP cells. DRP-27 also induced the activation of intracellular reactive oxygen species. Western blot analysis revealed that DRP-27 downregulated the expression of survivin, while activating Bax and DNA damage marker pH₂AX in LNCaP cells. In conclusion, our study suggests that DRP-27 might be an effective anti-cancer agent for PCa.

The cytotoxic, apoptotic and oxidative effects of carbonic anhydrase IX inhibitor on colorectal cancer cells

Colorectal cancer (CRC) is the third most common tumor, malignant and has developed one of the main reasons of cancer mortality. According to studies conducted recently; carbonic anhydrase 9 (CAIX) is an especially attractive target for cancer therapy, in part since it is limited way expressed in normal tissues on the other hand in a wide variety of solid neoplasia are overexpressed. The aim of this study was to appreciate the effects of CAIX inhibitor, namely novel synthesized sulfonamide derivative (H-4i) with high affinity for CAIX, in CAIX-positive human colorectal cancer cell (HT-29) and CAIX-negative human normal embryonic kidney cell line (HEK-293). For this reason, we planned to investigate apoptotic, cytotoxic and oxidative stress activity of H-4i on HT-29 and HEK-293 cell lines. Cell viability determined by WST-1 assay afterwards IC₅₀ values, apoptosis and cell cycle induction measured by flow cytometric analysis, intracellular free radical induction performed by reactive oxygen species (ROS) analyses. The IC₅₀ value of the sulfonamide derivative compound was found to be very low, especially in HT-29 cells, when compared to human normal cells. This research found that H-4i significantly increased cytotoxicity and ROS production, caused significant signs of apoptosis level. High level of ROS and apoptosis lead to arrest the cell cycle and reduce cell survival. The most obvious finding to emerge from the analysis that novel synthesized sulfonamide derivative H-4i is effective on HT-29 more than HEK-293. Therefore, novel derivative H-4i might be used as an anti-cancer potential compound on CRC.

Diversity Modification and Structure-Activity Relationships of Two Natural Products 1β-hydroxy Alantolactone and Ivangustin as Potent Cytotoxic Agents

Sesquiterpene lactones (STLs) are a class of plant secondary metabolites widely found in nature with potent antitumor activities. In this work, two isolated STLs 1β-hydroxy alantolactone (1) and ivangustin (2) were derivatized through diversity-oriented strategy, and in vitro cytotoxic activity assessments were conducted against six cell lines including HeLa, PC-3, HEp-2, HepG2, CHO and HUVEC. The cytotoxic structure-activity relationship showed that the double bond between C5 and C6 was beneficial to improve activity; C1-OH oxidized derivatives showed a slight stronger activity, comparable to the positive drug etoposide (VP-16). Yet, C1-OH esterified derivatives decreased the potency which were different from those of 1-O-acetylbritannilactone (ABL) reported previously by us, and C13-methylene reductive and spiro derivatives resulted in almost complete ablation of cytotoxic activity. Mechanistic basis of cytotoxicity of the representative compound 1i was assayed to relate with apoptosis and cell cycle arrest. Furthermore, 1i inhibited TNF-α-induced canonical NF-κB signaling in PC-3 cells. Molecular modeling studies exhibited additional hydrogen bond interaction between 1i and the residue Lys37 of p65, indicating that 1i could form covalent protein adducts with Cys38 on p65.

Santamarine Inhibits NF-кB and STAT3 Activation and Induces Apoptosis in HepG2 Liver Cancer Cells via Oxidative Stress

Sesquiterpene lactones have long been used in traditional Chinese medicines to treat inflammatory diseases. Recently, sesquiterpene lactone family compounds have been recognized as potential anticancer agents. Thus, it is necessary to explore new sesquiterpene lactones and their antitumor mechanism for cancer treatments. In the present study, we have explored the potential anti-cancer activity of a novel sesquiterpene lactone compound “santamarine” (STM) in HepG2 cells. It inhibited proliferation and induced apoptosis dose-dependently with IC₅₀ ~ 70 μM. Induction of apoptosis was found to be linked with increased reactive oxygen species (ROS) generation, decreased activity of thioredoxin reductase (TrxR), glutathione (GSH) depletion, mitochondrial membrane potential (ΔΨm) dissipation, Bcl-2 family proteins modulation, cytochrome c release, caspases-9, -8 and -3 activation and PARP cleavage. Further mechanistic study demonstrated that STM inhibited the constitutive and TNF-α-induced translocation of NF-кB into nucleus by decreasing phosphorylation of IkB-α. Moreover, STM inhibited STAT3 activation by decreasing phosphorylation at tyrosine705. NAC pretreatment reversed the effect of STM-mediated cell death, NF-кB inhibition and blockage of STAT3 activity, indicating the involvement of oxidative stress in STM-mediated anticancer activity. Further studies are needed to explore the exact molecular mechanism of STM-induced apoptosis to develop it into a lead for treatment of liver cancer in future.

A novel deubiquitinase inhibitor b-AP15 triggers apoptosis in both androgen receptor-dependent and -independent prostate cancers

Prostate cancer (PCa) remains a leading cause of cancer-related death in men. Especially, a subset of patients will eventually progress to the metastatic castrate-resistant prostate cancer (CRPC) which is currently incurable. Deubiquitinases (DUBs) associated with the 19S proteasome regulatory particle are increasingly emerging as significant therapeutic targets in numerous cancers. Recently, a novel small molecule b-AP15 is identified as an inhibitor of the USP14/UCHL5 (DUBs) of the 19S proteasome, resulting in cell growth inhibition and apoptosis in several human cancer cell lines. Here, we studied the therapeutic effect of b-AP15 in PCa, and our results indicate that (i) b-AP15 decreases viability, proliferation and triggers cytotoxicity to both androgen receptor-dependent and -independent PCa cells in vitro and in vivo, associated with caspase activation, inhibition of mitochondria function, increased reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress; (ii) pan-caspase inhibitor z-VAD-FMK and ROS scavenger N-acetyl-L-cysteine (NAC) efficiently block apoptosis but not proteasome inhibition induced by exposure of b-AP15; (iii) treatment with b-AP15 in androgen-dependent prostate cancer (ADPC) cells down-regulates the expression of androgen receptor (AR), which is degraded via the ubiquitin proteasome system. Hence, the potent anti-tumor effect of b-AP15 on both androgen receptor-dependent and -independent PCa cells identifies a new promising therapeutic strategy for prostate cancer.

Glutamate Toxicity to Differentiated Neuroblastoma N2a Cells Is Prevented by the Sesquiterpene Lactone Achillolide A and the Flavonoid 3,5,4'-Trihydroxy-6,7,3'-Trimethoxyflavone from Achillea fragrantissima

Glutamate toxicity is a major contributor to the pathophysiology of numerous neurodegenerative diseases including amyotrophic lateral sclerosis and Alzheimer's disease. Therefore, protecting neuronal cells against glutamate-induced cytotoxicity might be an effective approach for the treatment of these diseases. We have previously purified from the medicinal plant Achillea fragrantissima two bioactive compounds which were not studied before: the sesquiterpene lactone achillolide A and the flavonoid 3,5,4'-trihydroxy-6,7,3'-trimethoxyflavone (TTF). We have shown that these compounds protect astrocytes from oxidative stress-induced cell death and inhibit microglial activation. The current study examined for the first time their effects on differentiated mouse neuroblastoma N2a cells and on glutamate toxicity. We have found that, although these compounds belong to different chemical families, they protect neuronal cells from glutamate toxicity. We further demonstrate that this protective effect might be, at least partially, due to inhibitory effects of these compounds on the levels of reactive oxygen species produced following treatment with glutamate.

The sesquiterpene α-bisabolol in the adipocyte-cancer desmoplastic crosstalk: does it have an action on epithelial-mesenchymal transition mechanisms?

Alpha-bisabolol is a plant-derived sesquiterpene alcohol recently associated with a supposed anti-cancer action due to its ability to induce BID-related apoptosis. The molecule, which enters the cell through lipid rafts, may also interact with kisspeptin receptor 1, which has recently been associated with tumor mobility and invasiveness. This evidence suggests the possibility that α-bisabolol might act on the epithelial-mesenchymal transition mechanism, closely associated with the desmoplastic reaction of adipose tissue surrounding a pancreatic ductal adenocarcinoma. This review addresses the issue on the basis of the most recent reported literature in the field.

Biodegradable Polymeric Nanocapsules Prevent Cardiotoxicity of Anti-Trypanosomal Lychnopholide

Chagas disease is a neglected parasitic disease caused by the protozoan Trypanosoma cruzi. New antitrypanosomal options are desirable to prevent complications, including a high rate of cardiomyopathy. Recently, a natural substance, lychnopholide, has shown therapeutic potential, especially when encapsulated in biodegradable polymeric nanocapsules. However, little is known regarding possible adverse effects of lychnopholide. Here we show that repeated-dose intravenous administration of free lychnopholide (2.0 mg/kg/day) for 20 days caused cardiopathy and mortality in healthy C57BL/6 mice. Echocardiography revealed concentric left ventricular hypertrophy with preserved ejection fraction, diastolic dysfunction and chamber dilatation at end-stage. Single cardiomyocytes presented altered contractility and Ca²⁺ handling, with spontaneous Ca²⁺ waves in diastole. Acute in vitro lychnopholide application on cardiomyocytes from healthy mice also induced Ca²⁺ handling alterations with abnormal RyR2-mediated diastolic Ca²⁺ release. Strikingly, the encapsulation of lychnopholide prevented the cardiac alterations induced in vivo by the free form repeated doses. Nanocapsules alone had no adverse cardiac effects. Altogether, our data establish lychnopholide presented in nanocapsule form more firmly as a promising new drug candidate to cure Chagas disease with minimal cardiotoxicity. Our study also highlights the potential of nanotechnology not only to improve the efficacy of a drug but also to protect against its adverse effects.

Sesquiterpene lactones and scopoletins from Artemisia scoparia Waldst. & Kit. and their angiotensin I-converting enzyme inhibitory activities

Ten compounds, including a new guaiane-type sesquiterpene lactone, were isolated from the aerial parts of Artemisia scoparia. The structure of the new compound was determined to be 5-hydroxyguaia-3(4),11(13),10(14)-trien-6α,12-olide, named scoparanolide. Six known sesquiterpene lactones [estafiatone, 3β,4α-dihydroxyguaia-11(13),10(14)-dien-6α,12-olide, estafiatin, preeupatundin, 3β-hydroxycostunolide, and ludovicin B] and three known coumarin derivatives (scopoletin, scoparone, and isofraxidin) were identified by nuclear magnetic resonance and electrospray ionization mass spectroscopy. Six known sesquiterpene lactones were found for the first time in this plant. The angiotensin I-converting enzyme inhibitory activities of coumarin derivatives and scopoletins were significantly higher compared to those of sesquiterpene lactones and quercetin.

Rutin ameliorates cisplatin-induced reproductive damage via suppression of oxidative stress and apoptosis in adult male rats

Cisplatin (CP) treatment causes damage in the male reproductive system. Rutin (RUT) is a naturally occurring flavonoid glycoside that has antioxidant and anti-inflammatory properties. This study aimed to investigate effects of RUT against cisplatin-induced reproductive toxicity in male rats. Twenty-one adult male Sprague Dawley rats were used. The control group received physiological saline with oral gavage during 14 days, and physiological saline was injected intraperitoneally (IP) in 10th days of study. CP Group received physiological saline during 14 days, and 10 mg kg^-1 CP was injected IP in 10th day. RUT + CP group received RUT (150 mg kg^-1 ) during 14 days, and 10 mg kg^-1 CP was injected IP in 10th day. Spermatological parameters (including motility, cauda epididymal sperm density, dead sperm percentage and morphological sperm abnormalities), biochemical (MDA, GSH, GSH-px, SOD and CAT), histological (H&E dye) and immunochemistry evaluations of testicles were evaluated. CP treatment caused damage on some spermatological parameters, increased the oxidative stress and induced testicular degeneration and apoptosis when compared to the control group. However, RUT treatment mitigates these side effects when compared to the CP alone group. IT is concluded that RUT treatment may reduce CP-induced reproductive toxicity as a potential antioxidant compound.

Achillolide A Protects Astrocytes against Oxidative Stress by Reducing Intracellular Reactive Oxygen Species and Interfering with Cell Signaling

Achillolide A is a natural sesquiterpene lactone that we have previously shown can inhibit microglial activation. In this study we present evidence for its beneficial effects on astrocytes under oxidative stress, a situation relevant to neurodegenerative diseases and brain injuries. Viability of brain astrocytes (primary cultures) was determined by lactate dehydrogenase (LDH) activity, intracellular ROS levels were detected using 2',7'-dichlorofluorescein diacetate, in vitro antioxidant activity was measured by differential pulse voltammetry, and protein phosphorylation was determined using specific ELISA kits. We have found that achillolide A prevented the H₂O₂-induced death of astrocytes, and attenuated the induced intracellular accumulation of reactive oxygen species (ROS). These activities could be attributed to the inhibition of the H₂O₂-induced phosphorylation of MAP/ERK kinase 1 (MEK1) and p44/42 mitogen-activated protein kinases (MAPK), and to the antioxidant activity of achillolide A, but not to H₂O₂ scavenging. This is the first study that demonstrates its protective effects on brain astrocytes, and its ability to interfere with MAPK activation. We propose that achillolide A deserves further evaluation for its potential to be developed as a drug for the prevention/treatment of neurodegenerative diseases and brain injuries where oxidative stress is part of the pathophysiology.

Mitigation of paracetamol-induced reproductive damage by chrysin in male rats via reducing oxidative stress

Paracetamol (PRC) is a nonsteroidal anti-inflammatory drug used widely as a painkiller for various diseases and as the symptomatic flu cure in several countries worldwide. PRC toxicity may occur under conditions of the overdose usage. Chrysin (CR) is a flavonoid that is naturally present in several plants, honey and propolis. The aim of this study was to investigate the effects of CR (at the doses of 25 mg kg^-1 and 50 mg kg^-1 ) pre-treatment over seven consecutive days against PRC-induced reproductive toxicity in male rats. Our results showed that PRC toxicity decreased the sperm motility, and increased dead sperm rate, abnormal sperm cell rate, apoptosis and MDA levels in testicular tissues. Pre-treatment with CR at the dose of 25 and 50 mg kg^-1 for 7 days mitigated side effects of acute PRC toxicity in male reproductive system proportionally in a dose-dependent manner. This possible protection mechanism might be dependent on the antioxidant activity of CR. In conclusion, pre-treatment with CR at the dose of 25 and 50 mg kg^-1 for 7 days can be the beneficial against PRC-induced reproductive toxicity proportionally in a dose-dependent manner.

Investigation of the Antiproliferative Properties of Natural Sesquiterpenes from Artemisia asiatica and Onopordum acanthium on HL-60 Cells in Vitro

Plants and plant extracts play a crucial role in the research into novel antineoplastic agents. Four sesquiterpene lactones, artecanin (1), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guaia-11(13)-en-12,6α-olide (2), iso-seco-tanapartholide 3-O-methyl ether (3) and 4β,15-dihydro-3-dehydrozaluzanin C (4), were isolated from two traditionally used Asteraceae species (Onopordum acanthium and Artemisia asiatica). When tested for antiproliferative action on HL-60 leukemia cells, these compounds exhibited reasonable IC₅₀ values in the range 3.6–13.5 μM. Treatment with the tested compounds resulted in a cell cycle disturbance characterized by increases in the G1 and G2/M populations, while there was a decrease in the S phase. Additionally, 1–3 elicited increases in the hypodiploid (subG1) population. The compounds elicited concentration-dependent chromatin condensation and disruption of the membrane integrity, as revealed by Hoechst 33258–propidium staining. Treatment for 24 h resulted in significant increases in activity of caspases-3 and -9, indicating that the tested sesquiterpenes induced the mitochondrial pathway of apoptosis. The proapoptotic properties of the sesquiterpene lactones were additionally demonstrated withannexin V staining. Compounds 1 and 2 increased the Bax/Bcl-2 expression and decreased the expressions of CDK1 and cyclin B2, as determined at the mRNA level by means of RT-PCR. These experimental results indicate that sesquiterpene lactones may be regarded as potential starting structures for the development of novel anticancer agents.

Lead Phytochemicals for Anticancer Drug Development

Cancer is a serious concern at present. A large number of patients die each year due to cancer illnesses in spite of several interventions available. Development of an effective and side effects lacking anticancer therapy is the trending research direction in healthcare pharmacy. Chemical entities present in plants proved to be very potential in this regard. Bioactive phytochemicals are preferential as they pretend differentially on cancer cells only, without altering normal cells. Carcinogenesis is a complex process and includes multiple signaling events. Phytochemicals are pleiotropic in their function and target these events in multiple manners; hence they are most suitable candidate for anticancer drug development. Efforts are in progress to develop lead candidates from phytochemicals those can block or retard the growth of cancer without any side effect. Several phytochemicals manifest anticancer function in vitro and in vivo. This article deals with these lead phytomolecules with their action mechanisms on nuclear and cellular factors involved in carcinogenesis. Additionally, druggability parameters and clinical development of anticancer phytomolecules have also been discussed.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.