ABSTRACT
β-Elemene is an effective anti-cancer ingredient extracted from the genus Curcuma (Zingiberaceae familiy). In the present study, we demonstrated that β-elemene inhibited the proliferation of colorectal cancer cells and induced cell cycle arrest in the G2/M phase. In addition, β-elemene induced nuclear chromatin condensation and cell membrane phosphatidylserine eversion, decreased cell mitochondrial membrane potential, and promoted the cleavage of caspase-3, caspase-9 and PARP proteins, indicating apoptosis in colorectal cancer cells. At the same time, β-elemene induced autophagy response, and the treated cells showed autophagic vesicle bilayer membrane structure, which was accompanied by up-regulation of the expression of LC3B and SQSTM1. Furthermore, β-elemene increased ROS levels in colorectal cancer cells, promoted phosphorylation of AMPK protein, and inhibited mTOR protein phosphorylation. In the experiments in vivo, β-elemene inhibited the tumor size and induced apoptosis and autophagy in nude mice. In summary, β-elemene inhibited the occurrence and development of colon cancer xenografts in nude mice, and significantly induced apoptosis and autophagy in colorectal cancer cells in vitro. These effects were associated with regulation of the ROS/AMPK/mTOR signaling. We offered a molecular basis for the development of β-elemene as a promising anti-tumor drug candidate for colorectal cancer.
Subject(s)
Animals , Humans , Mice , AMP-Activated Protein Kinases/genetics , Apoptosis , Autophagy , Cell Line, Tumor , Colorectal Neoplasms/genetics , Mice, Nude , Reactive Oxygen Species , Sesquiterpenes , TOR Serine-Threonine Kinases/geneticsABSTRACT
We established a simple and sensitive GC-MS method for the determination of β-elemene in rat plasma and measured the pharmacokinetics of citronella grass extract in rats. Plasma samples were pretreated using liquid-liquid microextraction: 100 μL of plasma sample (containing naphthalene as the internal standard) was extracted with 50 μL of n-hexane. The determination was performed on DB-5ms column (30 m×0.25 mm, 0.25 μm). The initial column temperature was 60 ℃ and raised to 160 ℃ at a rate of 50 ℃·min-1, maintained for 3 min, and finally increased to 260 ℃ for 3 min. Helium was the carrier gas and the flow rate was 0.15 mL·min-1. The injection volume was 2 μL. EI and selected monitored ions pattern were used for ion scanning with m/z 128 (naphthalene) and m/z 93 (β-elemene). Citronella grass extract was administered to rats by intragastric administration and intravenous administration (containing β-elemene 55 mg·kg-1), and plasma was collected and prepared using an automated blood collection system. The linear range of β-elemene in plasma was 1.0-250 ng·mL-1 (r = 0.997), the limit of quantification was 1.0 ng·mL-1, the accuracy was -4.47% - -0.85%, the extraction recovery was between 56.02%-66.89%, and no obvious matrix effect (94.28%-108.63%) was found. The main pharmacokinetic parameters of β-elemene were AUC0-t (23.56 ± 4.40) ng·mL-1, tmax (1.67 ± 0.58) h, Cmax (7.36 ± 0.69) ng·mL-1, MRT0-t (2.76 ± 0.27) h, t1/2z (2.73 ± 1.36) h, Vz (7.39 ± 3.18) L·kg-1, CLz (1.95 ± 0.51) L·h-1·kg-1, and the absolute bioavailability was about 8.78%. The method is simple, accurate, and sensitive, and is suitable for the pharmacokinetic analysis of β-elemene in citronella grass extract in rats. All animal studies were implemented according to protocols, which were reviewed and approved by the Institutional Animal Care and Use Committee at Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences.
ABSTRACT
β-Elemene is the main active ingredient of elemene, a broad-spectrum anti-cancer botanical drug, which is also the main isomer of elemene's four isomers. The synthesis of some key intermediates were generalized and summarized during the derivatization of β-elemene, wherein the preparation methods, reaction conditions, yields, characterization data of these intermediates were listed. The purpose of this paper is to facilitate people in understanding and grasping the most optimal synthesis of these intermediates up to date, to inspire people pursuing further synthesis improvement, and to stimulate generation of new ideas for future derivatization of β-elemene.
ABSTRACT
Objective To verify the synergistic effect of transferrin modified β-elemene and celastrol co-loaded microemulsion (Tf-EC-MEs) on anti-colorectal cancer treatment. Methods The optimal mass ratio of β-elemene and celastrol to growth inhibition of Lovo and HT-29 colorectal cancer cells was optimized by MTT staining method in vitro. Tf-EC-MEs was prepared by “mixing-dripping” method, and the preparation and physicochemical properties of the particles were characterized by high performance liquid chromatography (HPLC), laser particle analyzer, and transmission electron microscope. The MTT staining, HPLC-BCA combined method, and Annexin V-PE/7-Aminoactinomycin D (Annexin V-PE/7-AAD) kit were used to investigate the antitumor activity of Tf-EC-MEs in vitro, and its effect on cell uptake, and apoptosis of tumor cells. The tumor-bearing nude mice model was established by subcutaneous injection of Lovo cells, and the tumor growth, weight, and survival time were observed after intravenous injection of β-elemene + celastrol, β-elemene-celastrol co-loaded microemulsion (EC-MEs), and Tf-EC-MEs. Results The combined administration of β-elemene and celastrol (40:1) had significant synergistic effect on the anti-colorectal cancer of Lovo and HT-29 cells. IC50 of β-elemene + celastrol in Lovo and HT-29 cells were (17.5 ± 2.9) and (36.4 ± 3.6) μg/mL, with the CI as 0.89 and 0.96, respectively. IC50 of Tf-EC-MEs in Lovo and HT-29 cells were (11.7 ± 0.6) and (27.4 ± 1.2) μg/mL, with the CI as 0.61 and 0.72 respectively. The 4 h of Lovo uptake of Tf-EC-MEs was 7.2 μg/mg, which was 3.3 times higher than that of β-elemene + celastrol. Tf-EC-MEs induced apoptosis in 59.2% of Lovo cells, which was significantly higher than that in beta-elemene + celastrol and EC-MEs groups. Tf-EC-MEs showed the overwhelming inhibition of growth of Lovo tumor-bearing tumors. The survival rate of Tf-EC-MEs-treated mice was 37.5% at day 60. In Tf-EC-MEs treated group, HE staining sections of tumor tissues showed substantial cell necrosis and the Ki-67 immunohistochemical sections displayed the significant inhibition of proliferation of tumor cells. Conclusion Compared with the combination group (beta-elemene and celastrol) and EC-MEs groups, Tf-EC-MEs has a promising potential in the synergistic anti-colorectal cancer treatment.
ABSTRACT
β-elemene is the sesquiterpene active monomer, as a national second-class non-cell toxic antitumor drugs which extracted from Zingiberaceae Curcuma rcenyujin. Moreover, β-elemene is currently used in clinic for treatment of lung cancer, liver cancer as well as breast cancer, and so on. Because of its broad-spectrum, safe, efficient, economical and other outstanding advantages in antitumor activities, leading to a broad application prospect in clinic. With the deep study of component and anticancer mechanisms of β-elemene, in order to promote its bioavailability and anticancer activity, researchers have screened a great deal of significant effective derivatives, and designed its liposome, microemulsion and other new drug delivery systems, which provide scientific theoretical guidance for further development and utilization of β-elemene. In this study, a systematic illustration was made for the current advance of pharmacological effects and mechanisms of β-elemene on treating cancer. In addition, the important derivatives, new drug delivery systems, and adverse reactions of β-elemene also be clarified, aiming to provide ideas for further scientific research and innovation of β-elemene.
ABSTRACT
AIM:To investigate the effect of β-elemene on reversing hepatocyte growth factor(HGF)-induced resistance to gefitinib in PC-9 cells, and to explore its possible mechanisms.METHODS: The gefitinib-resistant PC-9 cells induced by HGF were treated with β-elemene or/and gefitinib.The cell activity was measured by MTT assay.The effect of β-elemene on the invasion ability in HGF-induced resistance to gefitinib in PC-9 cells was detected by Transwell migration assay.The protein levels of p-Met, c-Met, p-AKT and AKT in PC-9 cells of each group were determined by Western blot.RESULTS:The results of MTT assay showed that the cell activity of PC-9 cells was significantly inhibited by β-elemene(P<0.05).IC50of β-elemene for PC-9 cells was 169.31 mg/L.IC50of gefitinib for PC-9 cells was 0.30 μmol/L.Exogenously adding recombinant HGF induced significantly resistance to gefitinib in PC -9 cells.Moreover, SU11274(an inhibitor of c-Met)significantly decreased the viability of the cells exposed to HGF and gefitinib(P <0.05).Combined treatment with β-elemene and gefitinib in the presence of HGF(50 μg/L)significantly decreased the viability of PC-9 cells as compared with the PC-9 cells treated with gefitinib alone in the presence of HGF(P<0.05),so did the result of the cell migration.The protein levels of p-Met and p-AKT were significantly up-regulated by HGF,while the protein levels of p-Met and p-AKT were markedly down-regulated in the cells treated with β-elemene and gefitinib com-pared with gefitinib alone in the presence of HGF.CONCLUSION: β-elemene reverses HGF-induced resistance to ge-fitinib in lung cancer PC-9 cells,likely due to the inhibition of HGF-induced activation of c-Met and its down streams sig-naling pathways(P<0.01).
ABSTRACT
Cancer is a serious threat to human health with a high fatality rate. Modern anticancer methods, including surgery, radiotherapy, and chemotherapy, commonly have more serious side effects. Anticancer plant essential oils which now attach great importance to cancer treatment, have many advantages such as multi-target, multi-effect, low adverse reaction, improving the body immunity, not easy to produce drug resistance, etc. The main active ingredients and the anticancer mechanism of essential oils were reviewed in this paper. Nineteen kinds of plant essential oils, including Cymbopogon flexuosus, Salvia officinalis, Lycopus lucidus, Lavandula angustifolia, Smyrnium olusatrum, peel of Citrus reticulate, leaves of Myrica rubra, and so on, displayed their prominent anti-cancer activities. Specifically, limonene, β-elemene, menthol, patchouli alcohol, thymol, eugenol, citral, β-caryophyllene, and their oxide may be the main anticancer composition of plant essential oils.
ABSTRACT
Objective To establish a RP-HPLC method for the determination of encapsulation efficiency (EE) and medicine loading (ML) in β-elemene-loaded Nano Polymeric Micelles; To study its release characteristic in vitro. Methods DSPE-PEG2000 was used as carrier to prepare medicine-loaded micelles. EE and ML were determined by petroleum ether extraction method, and its release characteristic in vitro was studied by dialysis method. Results The average EE and ML ofβ-elemene-loaded Nano Polymeric Micelles were 89.47%and 8.33%, respectively. Its release characteristic was slow. Conclusion The method for EE and ML determination is simple and accurate, and the prepared micelles have the property of sustained release.
ABSTRACT
Objective To investigate the effects of β-Elemene on the apoptosis of human pancreatic cancer Panc-1 cells; To discuss its mechanism of action. Methods β-Elemene (10, 20, 40, 80, 160 μg/mL) were incubated to the Panc-1 cells in vitro cultured for 24 h, 48 h and 72h, and trypan blue refusal method was used to detect cell inhibition rate;Apoptosis rate was measured by TUNEL; Hoechst33258 fluorescent staining was used to observe the changes of the nucleus. The activity of Caspase-3, 8 and 9 were detected by ELISA. Western blot was used to detect the expressions of Fas, FasL and Cyt c and AIF. Results The activity of Panc-1 cells was obviously inhibited time/concentration dependent inhibition (P<0.05, P<0.01), and the apoptosis rate increased after incubated with β-Elemene (P<0.01, P<0.001) after incubated with β-Elemene for 24 h, 48 h and 72 h; After giving β-Elemene 72 h, Panc-1 cells nucleus were broken obviously, and chromatin condensed and showed strong blue fluorescence, along with of apoptotic bodies; After incubated with β-Elemene for 48 h, Caspase-3, 8 and 9 activity significantly increased (P<0.05, P<0.01); protein expressions of Fas, FasL, Cyt c and AIF were significantly enhanced (P<0.05, P<0.01, P<0.001). Conclusion β-Elemene can inhibit Panc-1 cell proliferation, induce apoptosis, and the mechanism may be related to activating cell death receptor pathway and mitochondrial apoptosis pathway to play anti-tumor effects.
ABSTRACT
Objective To investigate the effect of β-elemene on SGC7901 gastric cancer cell line and the potential proteins involved. Methods Human SGC7901 gastric cancer cells were treated with different concentrations ofβ-elemene.Cell viability was assessed.A proteomic method,isobaric tags for relative and absolute quantitation (iTRAQ),was employed to detect the proteins altered by β-elemene.Protein expression was validated by Western blot.Results β-elemene inhibited the viability of SGC7901 gastric cancer cells in a dose-dependent manner.Altogether,147 upregulated proteins and 86 downregulated proteins were identified in response to β-elemene treatment in SGC7901 gastric cancer cell line.Among them,the expressions of p21-activated protein kinase-interacting protein 1 (PAK1IP1 ),Bcl-2-associated transcription factor 1 (BTF)and topoisomerase 2-alpha (TOPIIα)were validated by Western blot and the trends were consistent with iTRAQ results.Top pathways involved inβ-elemene treatment in SGC7901 gastric cancer cell line included ribosome signaling,peroxisome proliferator-activated receptors (PPARs)signaling pathway,regulation of actin cytoskeleton,phagosome,biosynthesis and metabolism of some amino acids.Conclusion Our results suggest a promising therapeutic role of β-elemene for gastric cancer.The differentially expressed proteins give us better insights into the potential mechanisms involved in gastric cancer treatment using β-elemene.
ABSTRACT
Objective To study the antiproliferative effect of DX2, a piperazine derivate of P-elemene, on human hepatoma HepG2 cells. Methods Cell viability was measured by MTT method. Morphological changes were observed by phase contrast microscopy and acridine orange staining. Apoptotic cell ratio was measured by flow cytometric analysis. Protein level was detected by Western blot analysis. Results DX2 Induced apoptotic morphological changes in HepG2 cells and increased the ratio of apoptotic cells. Treatment of HepG2 cells with DX2 increased the Bax/Bcl-2 ratio, induced the activation of caspase-9 and caspase-3 and caused the degradation of ICAD which was the substrate of capase-3. Conclusion DX2 Induces HepG2 cell death via activation of intrinsic mitochondrial pathway.
ABSTRACT
In the present study, a series of 13-β-elemene ester derivatives were designed and prepared, and their antioxidant activity was investigated in the H2O2-treated human umbilical vein endothelial cells (HUVECs). Among the test compounds, the dimer compounds 5v and 5w exhibited the most potent antioxidant activity with significant ROS suppression being observed. Both compounds markedly inhibited the H2O2-induced changes in various biochemical substances, such as superoxide dismutase (SOD), malonyldialdehyde (MDA), nitric oxide (NO), and lactic dehydrogenase (LDH), which were superior to that of the positive control vitamin E. Further more, they did not produce any obvious cytotoxicity, but increased the viability of HUVECs injured by H2O2 in a dose-dependent manner. Additionally, compound 5w, designed as a prodrug-like compound, showed improved stability relative to compound 4 in vitro.
Subject(s)
Humans , Antioxidants , Metabolism , Pharmacology , Cells, Cultured , Curcuma , Chemistry , Drug Stability , Drugs, Chinese Herbal , Chemistry , Pharmacology , Endothelium, Vascular , Cell Biology , Metabolism , Human Umbilical Vein Endothelial Cells , Hydrogen Peroxide , Metabolism , Malondialdehyde , Metabolism , Nitric Oxide , Metabolism , Oxidation-Reduction , Oxidative Stress , Phthalic Acids , Pharmacology , Sesquiterpenes , Pharmacology , Succinates , Pharmacology , Superoxide Dismutase , MetabolismABSTRACT
The present study aimed at investigating the possible effects of β-elemene on the progression of atherosclerosis in a rabbit model. The rabbit atherosclerosis model was established by the combination of balloon angioplasty-induced endothelial injury and an atherogenic diet fed to the rabbits. New Zealand White rabbits were randomly divided into four groups (8/group): the normal control group (fed with normal chow diet), and three experimental groups, placebo group, atorvastatin group, and β-elemene group (received the atherogenic diet). After two weeks on the diet, the three experimental groups underwent balloon injury at right common carotid artery and were treated with drugs or placebo for five weeks. Serum lipids were measured. Carotid artery lesions were isolated for histological and immunohistochemical analysis. In vitro, RAW264.7 macrophages were pretreated with β-elemene and ox-LDL for 24 h and the viability of macrophages was assayed using the MTT method. TNF-α and IL-6 were also determined. Compared with the control group, the thickness of the atherosclerosis lesion in the placebo group was significantly increased; The thickness the drug treatment groups were significantly decreased, compared with that of the placebo group. The infiltration of macrophage was markedly reduced in the β-elemene group compared with that of the placebo group. β-elemene treatment also reduced the levels of TC, TG, and LDL-C, compared with the placebo group. β-elemene decreased the TNF-α and IL-6 levels in vitro. In conclusion, our results demonstrated that β-elemene retarded the progression of atherosclerosis in vivo and in vitro, which may be related to the capacity of β-elemene to reduce the infiltration of macrophages and suppress inflammatory factors.
Subject(s)
Animals , Humans , Male , Rabbits , Atherosclerosis , Drug Therapy , Genetics , Allergy and Immunology , Pathology , Disease Models, Animal , Disease Progression , Interleukin-6 , Genetics , Allergy and Immunology , Macrophages , Allergy and Immunology , Sesquiterpenes , Tumor Necrosis Factor-alpha , Genetics , Allergy and ImmunologyABSTRACT
Objective To investigate the growth inhibition of β-elemene in ECV-304 cells,and study it's meaning to anti-angiogenesis in tumors.Methods The IC50 value of β-elemene in ECV-304 cells were got through MTT assay.Under treatment of β-elemene in ECV-304 cell,flow cytometry(FCM)was used to investigated the changing of cell cycle,electron microscope was used to show the morphological al-terations,agarose gel electrophoresis was used to detect effection on cells'DNA.Results The proliferation of ECV-304 cells was significantly inhibited by β-elemene,the IC50 value was (58.3 ±8.1)μg/ml.By FCM,we observed Cell cycle was significantly arrested in G0 /G1 phase under 60μg/ml treatment(P <0.05),apoptotic cells increased with the increase of drug concentrations.Typical apoptotic morphological alterations were found under electron microscope.Characteristic DNA-ladder standing for apoptosis was showed in agarose gel electrophoresis.Conclusions β-elemene can significantly inhibit ECV-304 cells'pro-liferation By inducing apoptosis.
ABSTRACT
Objective Pemetrexed and β-elemene can inhibit the growth of tumor cells .This study was to investigate the effect of pemetrexed combined with β-elemene on the proliferation and apoptosis of cervical cancer HeLa cells. Methods Cervical cancer HeLa cells were treated with pemetrexed at the concentrations of 38, 76, 152, 228, and 304μg/mL, and at 24 and 48 hours of treatment subjected to MTT for detection of their proliferation .The experiment included four groups , with the cells treated with β-elemene ( 125μg/mL) , pemetrexed ( 76 μg/mL ) , β-elemene ( 125 μg/mL ) +pemetrexed (76μg/mL), and nothing (blank control) for 24 hours, followed by determination of their proliferation and apoptosis by MTT and flow cytometry, respectively. Results Pemetrexed at 38, 76, 152 and 228μg/mL inhibited the proliferation of the HeLa cells in a concentration-dependent manner, with the inhibition rates of (7.24 ±3.78), (7.94 ±4.37), (11.10 ±2.86) and (15.88 ± 3.38)%at 24 hours, and (16.69 ±0.95), (22.54 ±1.53), (24.48 ±0.92) and (25.54 ±3.61)%at 48 hours, both with statis-tically significant differences between any two groups (P<0.05).Significant differences were also found in the proliferation rate of the same concentration of pemetrexed at the two time points (P<0.05).The combination of pemetrexed and β-elemene showed an inhibi-tion rate of (49.95 ±5.76)%at 24 hours, remarkably higher than (24.36 ±5.59)%in theβ-elemene group and (10.69 ±1.37)%in the pemetrexed group (P<0.01). Conclusion Pemetrexed combined with β-elemene can significantly inhibit the proliferation and synergistically accelerate the apoptosis of HeLa cells .
ABSTRACT
Arsenic trioxide (ATO) has been identified as an effective treatment for acute promyelocytic leukemia (APL) but is much less effective against solid tumors such as hepatocellular carcinoma (HCC). In the search for ways to enhance its therapeutic efficacy against solid tumors, we have examined its use in combination with a novel derivative of β-elemene, N-(β-elemene-13-yl)tryptophan methyl ester (ETME). Here we report the effects of the combination on cell viability, apoptosis, the cell cycle and mitochondria membrane potential (MMP) in HCC SMMC-7721 cells. We found that the two compounds acted synergistically to enhance antiproliferative activity and apoptosis. The combination also decreased the MMP, down-regulated Bcl-2 and pro-proteins of the caspase family, and up-regulated Bax and BID, all of which were reversed by the p53 inhibitor, pifithrin-α. In addition, the combination induced cell cycle arrest at the G2/M phase and reduced tumor volume and weight in an xenograft model of nude mice. Overall, the results suggest that ETME in combination with ATO may be useful in the treatment of HCC patients particularly those unresponsive to ATO alone.
ABSTRACT
Objective To explore the radiosensitivity ofβ-elemene on Colo320 cells transplanted tumor in nude mice and its molecular mechanisms.Methods Colo320 cells transplanted tumor model was established by cell suspension inoculation in nude mice.Then the transplanted mice with 0.8-1.0 cm3 tumor were randomly divided into 4 groups:control,β-elemene (40 mg/kg),radiation (4 Gy),andβ-elemene (40 mg/kg)+ radiation (4 Gy) groups,with four to five mice in each.Tumor weight and morphology were observed in each group.In addition,the apoptosis of tumor cells was measured by TUNEL and the expression of Fas gene was detected by immunohistochemistry.Results The nude mice transplanted tumor model was successfully established.Compared with that in control and simple radiation groups,tumor weight was significantly decreased inβ-elemene combined with irradiation group (P <0.05).At the same time,the apoptosis rate and the expression of Fas gene in tumor cells were significantly increased (P <0 .0 5 )inβ-elemene combined with irradiation group compared with control and simple radiation groups. Conclusion β-elemene could enhance the radiosensitivity of Colo320 cells transplanted tumor in nude mice probably by inducing Fas-mediated apoptosis of tumor cells.
ABSTRACT
This article was aimed to study the inhibition of cell proliferation and induction of apoptosis by β-el-emene extract from traditional Chinese medicine (TCM) Rhizoma Zedoariae on human hepatocellular carcinoma (HepG2) cells, as well as the effect on expression of apoptosis-related proteins in liver cancer-burdened H22 mice. Human HepG2 cells were cultured in vitro. MTT method was used in the determination of β-elemene on cell prolif-eration. Apoptosis of cells were detected by the Annexin V-FITC/PI double staining method. Through the establish-ment of liver cancer-burdened H22 mice model, the inhibition of cell proliferation and induction of apoptosis-related protein expression by β-elemene on tumor-burdened mice were observed. The results showed that β-elemene inhib-ited HepG2 cell proliferation, which was dose- and time-dependent. Annexin V-FITC/PI method detected early apoptotic cells. Inhibitions of tumor growth on tumor-burdened mice from different groups were different. Inhibition of tumor growth in the high-dose β-elemene group was relatively low, and that of the middle-dose was more obvi-ous. It was concluded that β-elemene can effectively inhibit human HepG2 cells proliferation. The inhibition on pro-liferation of cancer cells was through the inducing of cell apoptosis. It was also related to the upregulation of apopto-sis-related protein Caspase-3 and downregulation of NF-κB P65.
ABSTRACT
Objective: Optimizing the formula and preparation of β-elemene- polybutylcyanoacrylate nanoparticles (β-ELE-PBCA-NP). Methods: With polybutylcyanoacrylate (PBCA) as the drug-loaded material, β-ELE-PBCA-NP was prepared by interfacial polycondensation. The preparation conditions were optimized by single factor design and the formula was optimized by orthogonal design with entrapment efficiency (EE) as index. EE of β-ELE-PBCA-NP was determinated by RP-HPLC. Results: Under the optimal conditions, the prepared NPs were round and regular in shape without adhesions with average particle size of 254 nm and EE of 90.17%. Conclusion: The optimized technology in this experiment is stable and feasible.
ABSTRACT
Objective To study if β-elemene can increase radiation-induced deoxyribonucleic acid (DNA) damage and decrease the damage repair.Methods Exponentially growing human lung adenocarcinoma cells (A549) were exposed to 10 or 20 μg/ml β-elemene for 24 h before irradiation.The effect of β-elemene on the in vitro radiosensitivity of A549 cells was evaluated using clonogenic assay.DNA damage and repair were evaluated using comet assay.Results Exposure to β-elemene before irradiation increased the radiosensitivity of A549 cells.The SERD0 for 10 μg/ml and 20 μg/ml β-elemene was 1.55 and 1.64, respectively.The SERDq for 10 μg/ml and 20 μg/ml β-elemene was 1.43 and 1.75, respectively.Combined treatment, comparing to irradiation or β-elemene treatment alone, induced higher levels of DNA damage and slower rate of damage repair.A549 cells exposed to 20 μg/ml β-elemene followed by irradiation showed a higher levels of tail moment (TM) than those exposed to irradiation or β-elemene alone at 0 h,2 h,6 h and 24 h after irradiation.The TM of the three groups at 0 h,2 h,6 h and 24 h after irradiation was 7.16±2.61,0.95±0.65 and 1.81±1.23(F=231.24,P<0.01), 3.65±2.06,0.11±0.07 and 1.58±1.40(F=90.22,P<0.01), 2.09±0.83,0.1±0.05 and 0.45±0.25(F=238.44,P<0.01), 1.45±1.37,0.11±0.08 and 0.60±0.40(F=38.94,P<0.01), respectively. Conclusions β-elemene can enhance the radiosensitivity of A549 cells through the enhancement of DNA damage and the inhibition of DNA damage repair.