Elemene Antitumor Drugs Development Based on "Molecular Compatibility Theory" and Clinical Application: A Retrospective and Prospective Outlook

Elemene, derived from Curcuma wenyujin, one of the "8 famous genuine medicinal materials of Zhejiang province," exhibits remarkable antitumor activity. It has gained wide recognition in clinical practice for effectiveness on tumors. Dr. XIE Tian, introduced the innovative concept of "molecular compatibility theory" by combining Chinese medicine principles, specifically the "monarch, minister, assistant, and envoy" theory, with modern biomedical technology. This groundbreaking approach, along with a systematic analysis of Chinese medicine and modern biomedical knowledge, led to the development of elemene nanoliposome formulations. These novel formulations offer numerous advantages, including low toxicity, well-defined composition, synergistic effects on multiple targets, and excellent biocompatibility. Following the principles of the "molecular compatibility theory", further exploration of cancer treatment strategies and methods based on elemene was undertaken. This comprehensive review consolidates the current understanding of elemene's potential antitumor mechanisms, recent clinical investigations, advancements in drug delivery systems, and structural modifications. The ultimate goal of this review is to establish a solid theoretical foundation for researchers, empowering them to develop more effective antitumor drugs based on the principles of "molecular compatibility theory".

Clinical benefit and risk of elemene in cancer patients undergoing chemotherapy: a systematic review and meta-analysis

Introduction: Elemene injection and oral emulsion, known as elemene, have been utilized have been used in adjuvant therapy for cancer patients in China for more than 20 years. In order to evaluate the efficacy and potential risks of the treatments in cancer patients undergoing chemotherapy, a system review and meta-analysis were conducted. Additionally, the factors that may influence the outcomes were also explored. Methods: A comprehensive search was conducted across various databases including PubMed, Cochrane Library, Web of Science, EMBASE, CKNI, Wan Fang, and VIP databases. Meta-regression, subgroup, and sensitivity analyses were conducted to explore the heterogeneity. GRADE system and TSA were used to assess the strength of evidence and robustness of the results. Results: The pooled data showed that combination with elemene could improve the response rate (RR:1.48, 95%CI:1.38-1.60, p < 0.00001), disease control rate (RR:1.20, 95%CI:1.15-1.25, p < 0.00001), the rate of quality-of-life improvement and stability (WMD:1.31, 95% CI:1.12-1.53, p = 0.0006), immune function (CD4+/CD8+: WMD:0.33, 95% CI:0.24-0.42, p < 0.00001), survival rate (1-year, RR:1.34, 95% CI:1.15-1.56, p = 0.0002; 2-year, RR:1.57, 95% CI:1.14-2.16, p = 0.006), and decrease the prevalence of most chemotherapy-induced side effects, especially leukopenia (Ⅲ-Ⅳ) (RR:0.46, 95% CI:0.35-0.61, p < 0.00001), thrombocytopenia (RR:0.86, 95% CI:0.78-0.95, p = 0.003), and hemoglobin reduction (RR:0.83, 95% CI:0.73-0.95, p = 0.007). However, the administration of elemene has been found to significantly increase the incidence of phlebitis in patients undergoing chemotherapy (RR:3.41, 95% CI:1.47-7.93, p = 0.004). Meta-regression and subgroup analyses discovered that the outcomes were rarely influenced by CR, CT, and dosage of elemene (DE) but the cycle number of elemene (CNE) and TT were the main sources of heterogeneity. Discussion: As the treatment time and the number of cycles increased, the efficacy of the elemene combination decreased across various aspects. Thus, shorter duration and fewer cycles are recommended.

Thermo-sensitive injectable hydrogel loading with elemene-loaded liposomes for enhanced anti-tumor effect

Due to the heterogeneity and the complexity of the tumor microenvironment, combination therapy, especially the combination of chemotherapy and photothermal therapy (PTT), had received increasing attention. However, the co-delivery of small molecule drugs for chemotherapy and photothermal agents was a key issue. Herein, we prepared a novel thermo-sensitive hydrogel loading with elemene (ELE)-loaded and nano graphene oxide (NGO)-based liposomes for enhanced combined therapy. ELE was applied as the model drug for chemotherapy because it was a natural sesquiterpene drug with broad-spectrum and efficient antitumor activity. NGO was applied as drug carrier and photothermal agent simultaneously due to its two-dimensional structure and high photo-thermal conversion efficacy. NGO was further modified with glycyrrhetinic acid (GA) to improve its water dispersion, biocompatibility and tumor-targeting ability. ELE was loaded by GA-modified NGO (GA/NGO) to prepare the liposomes designated as ELE-GA/NGO-Lip, which was further mixed with chitosan (CS) solution and β-glycerin sodium phosphate (β-GP) solution to prepare the thermo-sensitive hydrogel designated as ELE-GA/NGO-Lip-gel. The obtained ELE-GA/NGO-Lip-gel had the gelling temperature of 37°C, temperature and pH-response gel dissolution and high photo-thermal conversion effect. More importantly, ELE-GA/NGO-Lip-gel upon 808 nm laser irradiation had relative high anti-tumor efficiency against SMMC-7721 cells in vitro. This research might provide a potent platform for the application of thermos-sensitive injectable hydrogel in combined tumor therapy.

Intravesical delivery of KDM6A-mRNA via mucoadhesive nanoparticles inhibits the metastasis of bladder cancer

This study provides proof-of-principle evidence for intravesical delivery of messenger RNA (mRNA) via a mucoadhesive nanoparticle (NP) strategy and reveals the therapeutic potential of KDM6A in treating bladder cancer metastasis, which remains difficult due to the physiological bladder barriers. The mucoadhesive NPs could protect loaded mRNA, prolong exposure of mRNA in disease sites, and benefit the penetration and effective expression, which all represent challenging hurdles for intravesical delivery of mRNA therapeutics. mRNA local delivery can also avoid potential toxicity issues via systemic delivery and unwanted protein expression throughout the body. We expect this mucoadhesive mRNA nanotechnology can be useful for the effective up-regulation of targeted proteins in bladder tissues in situ for both mechanistic understanding and translational study of bladder-related diseases.

Lysine-specific demethylase 6A (KDM6A), also named UTX, is frequently mutated in bladder cancer (BCa). Although known as a tumor suppressor, KDM6A’s therapeutic potential in the metastasis of BCa remains elusive. It also remains difficult to fulfill the effective up-regulation of KDM6A levels in bladder tumor tissues in situ to verify its potential in treating BCa metastasis. Here, we report a mucoadhesive messenger RNA (mRNA) nanoparticle (NP) strategy for the intravesical delivery of KDM6A-mRNA in mice bearing orthotopic Kdm6a-null BCa and show evidence of KDM6A’s therapeutic potential in inhibiting the metastasis of BCa. Through this mucoadhesive mRNA NP strategy, the exposure of KDM6A-mRNA to the in situ BCa tumors can be greatly prolonged for effective expression, and the penetration can be also enhanced by adhering to the bladder for sustained delivery. This mRNA NP strategy is also demonstrated to be effective for combination cancer therapy with other clinically approved drugs (e.g., elemene), which could further enhance therapeutic outcomes. Our findings not only report intravesical delivery of mRNA via a mucoadhesive mRNA NP strategy but also provide the proof-of-concept for the usefulness of these mRNA NPs as tools in both mechanistic understanding and translational study of bladder-related diseases.

Recent Advances in Understanding the Mechanisms of Elemene in Reversing Drug Resistance in Tumor Cells: A Review

Malignant tumors are life-threatening, and chemotherapy is one of the common treatment methods. However, there are often many factors that contribute to the failure of chemotherapy. The multidrug resistance of cancer cells during chemotherapy has been reported, since tumor cells' sensitivity decreases over time. To overcome these problems, extensive studies have been conducted to reverse drug resistance in tumor cells. Elemene, an extract of the natural drug Curcuma wenyujin, has been found to reverse drug resistance and sensitize cancer cells to chemotherapy. Mechanisms by which elemene reverses tumor resistance include inhibiting the efflux of ATP binding cassette subfamily B member 1(ABCB1) transporter, reducing the transmission of exosomes, inducing apoptosis and autophagy, regulating the expression of key genes and proteins in various signaling pathways, blocking the cell cycle, inhibiting stemness, epithelial-mesenchymal transition, and so on. In this paper, the mechanisms of elemene's reversal of drug resistance are comprehensively reviewed.

Elemene Nanoemulsion Inhibits Metastasis of Breast Cancer by ROS Scavenging

Introduction

Elemene (C₁₅H₂₄) is a sesquiterpene compound extracted from the rhizome of Curcuma herbs. In the past decades, the anti-tumor activity of elemene has been observed in vitro and in some clinical practices. However, pharmacological mechanisms of elemene are not demonstrated adequately, which may lead to improper clinical applications. This study aimed to investigate the anti-tumor effect of elemene nanoemulsion in the mouse model of triple-negative breast cancer (TNBC) and reveal the underlying mechanisms.

Methods

The ESR measurement and quantum mechanics simulation were used to characterize the antioxidant ability of elemene nanoemulsion. The murine breast cancer cell line 4T1 cells were inoculated subcutaneously into the left fourth mammary fat pad of BalB/c mice to establish a TNBC mice model. The H&E staining, immunohistochemical staining, DHE staining and Western blot were employed to evaluate the therapeutic effects of the elemene nanoemulsion on the TNBC mice.

Results

It was shown that the elemene nanoemulsion prolonged the survival of the triple-negative breast cancer-bearing mice and inhibited the metastasis to lung and liver while did not induce significant cytotoxicity to the tumor cells. Mechanistic studies demonstrated that the elemene nanoemulsion effectively scavenged the reactive oxygen species (ROS) in vitro and in vivo, which decreased the stabilization of hypoxia-inducible factor-1α (HIF-1α) and consequently reduced angiogenesis in the tumor microenvironment as well as decreased the level of NLRP3 inflammasomes and IL-1β production. In addition, the elemene nanoemulsion downregulated the level of IL-1β in the RAW264.7 cells in exposure with LPS.

Conclusion

In conclusion, due to the ROS scavenging ability, elemene nanoemulsion effectively inhibited the metastasis of the breast cancer cells to lung and liver and consequently prolonged the survival of TNBC mice.

Diagnosis and treatment of chylous leakage after modified radical mastectomy for breast cancer: a case report

The post-operative complication of chylous leakage after breast cancer is relatively rare, and few clinical studies have been published. We report a 64-year-old woman with chylous leakage following modified radical mastectomy. We describe the patient's diagnostic and treatment process in detail. The patient was diagnosed with grade II (left) breast invasive ductal carcinoma. Post-operatively, the patient's chest wall and axilla were pressurized, and negative pressure drainage was initiated. On the fifth post-operative day, the drainage from the chest wall and axilla increased significantly, and the patient developed chylous leakage on the eighth postoperative day. We injected meglumine diatrizoate (100 mL) and elemene (10 mL) into the patient's axilla, and the chylous leakage gradually resolved 18 days post-operatively. In this report, we focus on managing a case of chylous leakage after modified radical mastectomy for breast cancer. Meglumine diatrizoate combined with elemene is a possible treatment for the management of this rare complication.

Efficacy and safety of elemene combined with chemotherapy in advanced gastric cancer: A Meta-analysis

BACKGROUND

Elemene is a natural compound extracted from Zingiberaceae plants, and is used in various cancer. However, the efficacy and safety elemene combined with chemotherapy in advanced gastric cancer (GC) are lack of systematic assessment.

METHODS

we searched the PubMed, EMBASE, Web of Science, Cochrane Library, China Academic Journals (CNKI), Chinese Science and Technology Journals (CQVIP) and Chinese Biomedical Literature databases. Randomized controlled trials (RCTs) comparing elemene plus chemotherapy with chemotherapy alone in participants with advanced GC and reporting at least one of the following outcomes were selected and assessed for inclusion. JADAD scale was used to assess the quality. Data was screened and extracted by two independent investigators. The primary clinical outcome was overall response rate (ORR); the secondary outcomes were quality of life (QOL) and adverse events (AEs). Analysis was performed using Review Manager 5.3.

RESULTS

Sixteen RCTs matched the selection criteria, which reported on 969 subjects. Risk ratios (RR) and corresponding 95% confidence intervals (CIs) were pooled for ORR, life quality based on KPS, and risk of AEs. Compared to chemotherapy alone, elemene combined with chemotherapy in the treatment of GC may increase the efficiency of ORR(RR: 1.41; 95% CI: 1.23-1.60; P < .0001), improve their life quality based on KPS (RR: 1.84; 95% CI: 1.45-2.34; P < .00001), and reduce the adverse reactions, including leukopenia(RR: 0.73; 95% CI: 0.62-0.85; P < .00001), neutropenia (RR: 0.75; 95% CI: 0.60-0.95; P = .02), anemia (RR: 0.76; 95% CI: 0.60-0.95; P = .02), thrombocytopenia (RR: 0.56; 95% CI: 0.43-0.73; P < .00001). Nausea and vomiting (RR: 0.84; 95% CI: 0.84-1.07; P = .39), diarrhea (RR: 0.69; 95% CI: 0.41-1.15; P = .15), neurotoxicity (RR: 0.77; 95% CI: 0.59-1.00; P = .05) and hepatic dysfunction (RR: 0.95; 95% CI: 0.58-1.54; P = .83) were similar between two groups.

CONCLUSIONS

Elemene may have the potential to improve the efficacy and reduce the AEs of chemotherapy for gastric cancer. However, the long-term, high-quality researches with a large sample size in different populations are required.

Elemene injection combined with transcatheter arterial chemoembolization for unresectable hepatocellular carcinoma: A meta-analysis

BACKGROUND

To evaluate the short-term efficacy, long-term efficacy, and adverse events (AEs) of elemene plus transcatheter arterial chemoembolization (TACE) in comparison with TACE alone for the treatment of hepatocellular carcinoma (HCC).

METHODS

PubMed, EMBASE, the Cochrane Library, the Chinese Scientific Journal Full-text Database, Wanfang Data, CBM, and VIP were searched by 2 reviewers using the same search strategy for clinical studies on elemene plus TACE in the treatment of HCC. These articles were screened according to pre-established inclusion and exclusion criteria, and the qualities of the included studies were assessed using the Newcastle-Ottawa scale. The primary outcomes were the objective response rate (ORR), the 1-year survival rate and AEs. Review Manager 5.3 and Stata 15.0 were used for the meta-analysis.

RESULTS

A total of 10 studies involving 543 patients (TACE + elemene = 277, TACE alone = 266) were included. The results showed that the ORR was significantly improved in the combined treatment group compared to the TACE alone group (odds ratio [OR] = 2.72, 95% confidence interval [CI]: 1.84-4.00, P < .05). TACE + elemene significantly increased the 1-year survival rate (OR = 2.79, 95% CI: 1.58-4.95, P < .05). We also found no significant difference in gastrointestinal reactions (OR = 0.97, 95% CI: 0.57-1.64, P = .90), fever (OR = 0.80, 95% CI: 0.37-1.71, P = .56), or bone marrow suppression (OR = 0.73, 95% CI: 0.44-1.22, P = .23) between the 2 groups.

CONCLUSION

Based on current findings, TACE + elemene injection may improve the ORR and the 1-year survival rate for HCC patients compared to TACE alone. Arterial perfusion may be superior to intravenous guttae.

Regulation of signaling pathways by β-elemene in cancer progression and metastasis

Entry of β-elemene into various phases of clinical trials advocates its significance as a premium candidate likely to gain access to mainstream medicine. Based on the insights gleaned from decades of research, it seems increasingly transparent that β-elemene has shown significant ability to modulate multiple cell signaling pathways in different cancers. We partition this multicomponent review into how β-elemene strategically modulates various signal transduction cascades. We have individually summarized regulation of tumor necrosis factor related apoptosis-inducing ligand, signal transducers and activators of transcription, transforming growth factor/SMAD, NOTCH, and mammalian target of rapamycin pathways by β-elemene. Last, we will discuss the results of clinical trials of β-elemene and how effectively we can use these findings to stratify patients who can benefit most from β-elemene.

β-Elemene Synergizes With Gefitinib to Inhibit Stem-Like Phenotypes and Progression of Lung Cancer via Down-Regulating EZH2

The inhibitors for EGF receptor tyrosine kinase (EGFR-TKIs) such as gefitinib have been used as a standard treatment for non-small cell lung cancer (NSCLC), but the increasingly occurrence of drug resistance, the associated adverse effects and the enrichment of cancer stem cells significantly impedes its clinical application. β-elemene is a natural sesquiterpene with potent anti-cancer ability, and also it is renowned for its plant-origin, safety and the additive effect with traditional therapies, which prompt us to explore its potential to co-operate with TKIs to achieve greater therapeutic efficacy. Impressively, our study demonstrates that, elemene, in combination of gefitinib, displayed a significantly higher activity in inhibiting lung cancer cellular proliferation, migration and invasion. More importantly, combinative treatment profoundly impaired the epithelial to mesenchymal transition (EMT), the stem-like properties and the self-renewal capacity of lung cancer cells, and hence impeded the in vivo tumor development. We also reveal that the synergistic anti-tumor effect of elemene and gefitinib was largely mediated their regulation of enhancer of zeste homolog 2 (EZH2), an oncogenic histone methyltransferase and gene transcriptional regulator. Thus, our data indicate that combinative treatment of elemene and gefitinib has greater anti-neoplastic activity and greater efficacies in targeting cancer stem-like properties, mainly through regulating the malignant gene modifier and hence the subsequent effector molecules required for cancer progression. The findings may have potential implications for treating aggressive and resistant lung cancers.

Evaluation of the efficacy and safety of elemene in treating malignant pleural effusion caused by tumors: A PRISMA guided meta-analysis

OBJECTIVE

Elemene is widely used to treat malignant pleural effusion in China. This meta-analysis aimed to evaluate the efficacy and safety of elemene in treating malignant pleural effusion.

METHODS

Electronic databases including Pubmed, the Cochrane Library, Embase and Chinese biomedical literature database were searched until March 2017. Clinical controlled trials (CCTs) assessing the efficacy and safety of elemene in the treatment of malignant pleural effusion were included. The quality of the included studies was evaluated using the quality evaluation criteria of the Cochrane Handbook version 5.1.0.

RESULTS

A total of 46 CCTs were included, with 2992 patients. Results of meta-analysis showed that elemene significantly improved the overall response rate (ORR) in controlling malignant pleural effusion (risk ratio [RR] = 1.16; 95% CI: 1.08-1.23; P < .05). Subgroup results showed that the ORR of elemene in the treatment of lung cancer patients with malignant pleural effusion (RR = 1.20, 95% CI: 1.07-1.34; P < .05) was higher than that of other cancers (RR = 1.14, 95% CI: 1.05-1.23; P < .05). Meanwhile, elemene did not significantly increase the incidences of chest pain and fever (P > .05).

CONCLUSION

Elemene is suggested to have the ability of improving the treatment outcome of malignant pleural effusion with acceptable safety.

Elemene treatment for NSCLC with multiple CNS metastases: a case report and literature review

CNS metastases are common in patients with non-small-cell lung cancer (NSCLC) and is associated with poor prognosis. In NSCLC patients with EGFR mutations, and ALK fusion oncogene, chemotherapy is ineffective; however, targeted and pulse therapies may be used as alternative treatment options. Elemene can cross the blood-brain barrier and enter the brain tissue. In this paper, treatment consisting of elemene injections in a case of NSCLC with brain metastases, spinal metastases and a possible complication of leptomeningeal metastases is reported, and the efficacy of elemene in treating NSCLC with CNS metastases was investigated.

Preliminary evaluation of the potential role of β-elemene in reversing erlotinib-resistant human NSCLC A549/ER cells

β-elemene (β-ELE) is a natural compound extracted from Curcuma zedoaria Roscoe that has shown promise as a novel anticancer drug to treat malignant tumors. Recent studies have demonstrated that β-ELE can reverse the drug resistance of tumor cells. To the best of our knowledge, there are no reports concerning the reversal of erlotinib resistance by β-ELE in human non-small cell lung cancer (NSCLC) cells. Therefore, the present study investigated the effects of β-ELE on erlotinib-resistant human NSCLC A549/ER cells in vitro and its possible mechanism of action. The sensitivity of A549/ER cells to erlotinib, the cytotoxicity of β-ELE on the growth of A549/ER cells and the effects of β-ELE on the reversal of drug resistance in A549/ER cells were determined by MTT assay. The cell apoptosis rate, cell cycle phase distribution and intracellular rhodamine 123 (Rh123) fluorescence intensity were detected by flow cytometry. The expression level of P-glycoprotein (P-gp) was detected by western blotting. A549/ER cells had a stable drug-resistance to erlotinib. β-ELE inhibited the proliferation of A549/ER cells in a time- and dose-dependent manner, enhanced the sensitivity of A549/ER cells to erlotinib and reversed the drug resistance in A549/ER cells. Treatment with 15 µg/ml β-ELE combined with 10 µmol/l erlotinib caused an increased rate of cell apoptosis and G₀/G₁ phase arrest. Furthermore, β-ELE reduced the efflux of Rh123 from A549/ER cells, increased the intracellular accumulation of Rh123 and decreased the expression of P-gp. The results of the present study indicated that β-ELE could reverse drug resistance in erlotinib-resistant human NSCLC A549/ER cells in vitro through a mechanism that may involve the decreased expression of P-gp, inhibition of P-gp dependent drug efflux and the increased intracellular concentration of anticancer drugs.

Demethylation effects of elemene on the GSTP1 gene in HCC cell line QGY7703

The present study aimed to investigate elemene's effects on cell proliferation, apoptosis, and the cell cycle in the hepatocellular carcinoma (HCC) cell line, QYG7703, and to investigate GSTP1 gene methylation change in QGY7703 cells after being treated with elemene to explore whether elemene reversed the abnormal GSTP1 gene methylation. QGY7703 cells were treated with different elemene concentrations. Cell proliferation was measured with MTT assay, cell apoptosis and cell cycle were analyzed by flow cytometry, and GSTP1 gene methylation was analyzed by methlation-specific polymerase chain reaction. The cells' apoptotic rate increased dose-dependently with elemene concentration, and the difference was statistically significant (P<0.05). Elemene treatment arrested the cells in S phase, and thus the percentage of cells in G1 phase decreased while the cells in S phase increased dose-dependently, and the difference was statistically significant compared to the control group (P<0.05). All QGY7703 cells were identified to contain GSTP1 gene methylation before being treated with elemene and the methylation state decreased after treatment. In the present study, elemene induced cell apoptosis, inhibited the cell cycle, and reversed GSTP1 gene methylation in QGY7703 cells.

The effect of elemene on lung adenocarcinoma A549 cell radiosensitivity and elucidation of its mechanism

OBJECTIVE

To investigate the effect of elemene on the radiosensitivity of A549 cells and its possible molecular mechanism.

METHODS

Apoptosis of A549 cells was detected by flow cytometry and fluorescence microscopy. The effect of double-strand break (DSB) damage repair in A549 cells was evaluated using the neutral comet assay. Protein expression levels were detected using western blotting, and the correlation between protein levels was analyzed.

RESULTS

Elemene exhibited a radiosensitizing effect on A549 cells. The level of apoptosis induced by elemene combined with radiation was significantly greater (p<0.01) than that elicited by either radiation or elemene alone. Following radiation and subsequent repair for 24 h, the tail intensity of A549 cells treated with a combination of elemene and radiation was greater than that of cells treated with either elemene or radiation alone (p<0.01). This result indicates that elemene inhibits cellular DSB repair. Both elemene combined with radiation and radiation alone decreased the protein expression of DNA-PKcs and Bcl-2 compared to elemene alone (p<0.01), while p53 protein expression was increased (p<0.01). A negative correlation was observed between DNA-PKcs and p53 expression (r=-0.569, p=0.040), while a positive correlation was found between DNA-PKcs and Bcl-2 expression (r=0.755, p=0.012).

CONCLUSIONS

Elemene exhibits a radiosensitizing effect on A549 cells, and its underlying molecular mechanism of action may be related to the downregulation of DNA-PKcs gene expression.

β-elemene reverses the drug resistance of A549/DDP lung cancer cells by activating intracellular redox system, decreasing mitochondrial membrane potential and P-glycoprotein expression, and inducing apoptosis

BACKGROUND

β-elemene (β-ELE) injection is a new anticancer drug extracted from Curcuma zedoaria Roscoe that has been widely used to treat malignant tumors. Recent studies show that β-ELE reverses the drug resistance of tumor cells. To explore the possible mechanisms of β-ELE, we investigated its effects on cisplatin (DDP)-resistant human lung adenocarcinoma A549/DDP cells.

METHODS

The effects of β-ELE on the growth of A549/DDP cells in vitro were determined by MTT assay. Apoptosis was assessed by fluorescence microscopy with Hoechst 33258 staining, flow cytometry with Annexin V-FITC/propium iodide double staining; mitochondrial membrane potential using JC-1 fluorescence probe and laser confocal scanning microscopy, and intracellular reactive oxygen species levels were measured by 2',7'-dichlorfluorescein-diacetate staining and flow cytometry; and contents of cytosolic glutathione were determined by glutathione assay kits. Intracellular Rhodamine-123 fluorescence intensity was detected by flow cytometry, and the expression of P-glycoprotein (P-gp) was detected by Western blotting.

RESULTS

β-ELE inhibited the proliferation of A549/DDP cells in a time- and dose-dependent manner. Furthermore, β-ELE enhanced the sensitivity of A549/DDP cells to cisplatin and reversed the drug resistance of A549/DDP cells. Consistent with a role in activating apoptosis, β-ELE decreased mitochondrial membrane potential, increased intracellular reactive oxygen species concentration and intracellular accumulation of Rhodamine-123, decreased the cytoplasmic glutathione levels and the expression of P-gp in a time- and dose-dependent manner.

CONCLUSIONS

These results define a pathway of β-ELE function that involves decreased mitochondrial membrane potential and P-gp expression activated intracellular redox system, and induced apoptosis leading to reverse drug resistance.

Analysis of Cleistopholis patens leaf and trunk bark oils using combined GC- flame ionisation detection, GC-retention index, GC-MS and (13) C-NMR

INTRODUCTION

Germacrenes A-C are secondary metabolites produced by various plants. They are sesquiterpene hydrocarbons bearing the (E,E)-1,5-cyclodecadiene structure known to undergo thermal rearrangement through a [3.3]-sigmatropic reaction. Such a rearrangement was evidenced by comparing the contents of a given germacrene and the corresponding elemene calculated by GC-flame ionisation detection (FID) with the relative intensities of the signals of both molecules in the (13) C-NMR spectrum of the mixture, recorded at room temperature.

OBJECTIVE

To develop a protocol to identify and quantify germacrenes A, B and C and in parallel the corresponding elemenes, using a combination of GC-FID and (13) C-NMR and then provide a correct analysis of Cleistopholis patens essential oils.

METHODS

The essential oil was submitted to GC-FID, GC-retention index, GC-MS and (13) C-NMR analyses. The relative percentages of every couple of germacrene and elemene measured by GC-FID were summed. Then, the relative ratio of the mean intensities of the signals of the protonated carbons of a given germacrene and the corresponding elemene was calculated. The contents of both compounds were obtained by combining GC-FID and (13) C-NMR data.

RESULTS

The true content of germacrene A/β-elemene, germacrene B/γ-elemene and germacrene C/δ-elemene in leaf and root oils from C. patens was evaluated by combination of GC-FID and (13) C-NMR data. Correct analysis of the essential oils was provided.

CONCLUSION

Combined analysis of essential oil including (13) C-NMR without isolation of the components, appeared really efficient to identify and quantify germacrene isomers and in parallel elemene isomers in essential oils.

Mechanisms of inhibition of elemene on human lens epithelial cell proliferation in vitro

AIM

To study the effects of elemene (Ele) on proliferation and cell cycle of human lens epithelial cells B3 (HLE-B3) and the mechanisms of its signal transduction.

METHODS

Recombinant human basic fibroblast growth factor (rhbFGF) was used to induce proliferation of HLE-B3 cells, which were incubated with 80mg/L Ele for 24 hours. The inhibitory effects of Ele on the proliferation of HLE-B3 cells were evaluated by MTT method. The effect of Ele on HLE-B3 cell cycle was analyzed by flow cytometry(FCM). The expressions of protein kinase A (PKA) and protein kinase G (PKG) of HLE-B3 were also analyzed by FCM.

RESULTS

Ele altered the cell cycle of HLE-B3 and effectively inhibited HLE-B3 cell proliferation induced by rhbFGF. Ele up-regulated PKA and down-regulated the expression of PKG in HLE-B3 cell.

CONCLUSION

Ele inhibits HLE-B3 proliferation, making it an attractive potential agent in regimens to treat after-cataracts.

Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion

The objective was to develop an elemene oil/water (o/w) microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC) and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v), 5% ethanol (v/v), 15% propylene glycol (v/v), 15% glycerol (v/v), and 5% polysorbate 80 (w/v), was characterized as (57.7 ± 2.8) nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4) mv in zeta potential, (5.19 ± 0.08) in pH, 6 mpa·s in viscosity, (31.8 ± 0.3) mN·m⁻¹ in surface tension, (8.273 ± 0.018) mg·mL⁻¹ in content of β-elemene, and (99.81 ± 0.24)% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC_0→24h) of the elemene microemulsion and commercial elemene emulsion were integrated to be 3.092 mg·h·L⁻¹ and 1.896 mg·h·L⁻¹ respectively, yielding a relative bioavailability of 163.1%. The present study demonstrates the elemene microemulsion as a new formulation with ease of preparation, high entrapment efficiency, excellent clarity, good stability, and improved bioavailability.

Germacrene C synthase from Lycopersicon esculentum cv. VFNT cherry tomato: cDNA isolation, characterization, and bacterial expression of the multiple product sesquiterpene cyclase

Germacrene C was found by GC-MS and NMR analysis to be the most abundant sesquiterpene in the leaf oil of Lycopersicon esculentum cv. VFNT Cherry, with lesser amounts of germacrene A, guaia-6,9-diene, germacrene B, beta-caryophyllene, alpha-humulene, and germacrene D. Soluble enzyme preparations from leaves catalyzed the divalent metal ion-dependent cyclization of [1-3H]farnesyl diphosphate to these same sesquiterpene olefins, as determined by radio-GC. To obtain a germacrene synthase cDNA, a set of degenerate primers was constructed based on conserved amino acid sequences of related terpenoid cyclases. With cDNA prepared from leaf epidermis-enriched mRNA, these primers amplified a 767-bp fragment that was used as a hybridization probe to screen the cDNA library. Thirty-one clones were evaluated for functional expression of terpenoid cyclase activity in Escherichia coli by using labeled geranyl, farnesyl, and geranylgeranyl diphosphates as substrates. Nine cDNA isolates expressed sesquiterpene synthase activity, and GC-MS analysis of the products identified germacrene C with smaller amounts of germacrene A, B, and D. None of the expressed proteins was active with geranylgeranyl diphosphate; however, one truncated protein converted geranyl diphosphate to the monoterpene limonene. The cDNA inserts specify a deduced polypeptide of 548 amino acids (Mr = 64,114), and sequence comparison with other plant sesquiterpene cyclases indicates that germacrene C synthase most closely resembles cotton delta-cadinene synthase (50% identity).