Cytotoxic and antibacterial triterpenoids derivatives from Clematis ganpiniana

Ethnopharmacological relevance

The roots and rhizomes of Clematis are commonly used as an analgesic, abirritative, antibacterial, antiphlogistic, anticancer and diuretic agent. The Naxi people traditionally used Clematis ganpiniana's (Lévl. Et Vant.) as a diuretic agent, an anti-inflammatory and anticancer remedy.

Aim of study

To investigate the cytotoxic and antibacterial components from Clematis ganpiniana.

Materials and methods

The aboveground part of Clematis ganpiniana was isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods and comparison with published data. Their cytotoxic, apoptosis and antibacterial activities of purified components were also performed.

Results

By bioassay-guided fractionation techniques and chemical characterization, four triterpene glycosides were isolated and their cytotoxicity against cancer cells and antibacterial activity were tested. They showed significant inhibitory activities against MCF-7, MDA-MB-231 with IC50 value of 0.7–16.5 μg/ml, and significant apoptosis for MCF-7 and MDA-MB-231. Moreover, compound 4 showed weak wide-spectrum antibacterial activity.

Conclusion

These results provide promising baseline information for the potential use of Clematis ganpiniana as well as some of the isolated compounds in the treatment of cancer and infectious disease.     

Cytotoxic polyphenols against breast tumor cell in Smilax china L.

Ethnopharmacological relevance

Smilax china L., referred to ‘Ba Qia’ (or ‘Jin Gang Teng’) in China, is a small vine that grows in the southern parts of China. The roots and tubers of S. china L. have been applied not only as traditional Chinese medicine (TCM) for treatment of diuretic, rheumatic arthritic, detoxication, lumbago, gout, tumor, and inflammatory diseases, but also as food in some area of China.

Aim of study

To investigate the breast tumor cell toxic components in S. china L. continuously and systematically.

Materials and methods

Three fractions and six polyphenols were isolated from roots and tubers of S. china L. under bioassay-guided screenings. The structures of six compounds were elucidated by spectroscopic methods and comparison with published data. Their breast tumor cytotoxicity and apoptosis of purified components were performed.

Results

Six polyphenols were obtained on the basis of a bioassay-guided separation of the ethyl acetate extract, and their breast tumor cytotoxic activities were tested. They showed anti-tumor activities against MCF-7 and MDA-MB-231 with IC50 value of 2.1–38.9 μg/mL, and can induce apoptosis for MCF-7 and MDA-MB-231.

Conclusions

Among these six polyphenols, five (1, 3–6) were reported for the 1st time with in vitro activities on anti-breast tumor cell. It is likely that these polyphenols are the active components of S. china L. responsible for the anti-breast tumor cell activities.     

In vitro anti-breast cancer activity of ethanolic extract of Wrightia tomentosa: Role of pro-apoptotic effects of oleanolic acid and urosolic acid

Ethnopharmacological relevance

Wrightia tomentosa Roem. & Schult. (Apocynaceae) is known in the traditional medicine for anti-cancer activity along with other broad indications like snake and scorpion bites, renal complications, menstrual disorders etc. However, the anti-cancer activity of this plant or its constituents has never been studied systematically in any cancer types so far.

Aim of the study

To evaluate the anti-cancer activities of the ethanolic extract of W. tomentosa and identified constituent active molecule(s) against breast cancer.

Material and methods

Powdered leaves of W. tomentosa were extracted with ethanol. The ethanolic extract, subsequent hexane fractions and fraction F-4 of W. tomentosa were tested for its anti-proliferative and pro-apoptotic effects in breast cancer cells MCF-7 and MDA-MB-231.

Results

The ethanolic extract, subsequent hexane fractions and fraction F-4 of W. tomentosa inhibited the proliferation of human breast cancer cell lines, MCF-7 and MDA-MB-231. The fraction F-4 obtained from hexane fraction inhibited proliferation of MCF-7 and MDA-MB-231 cells in concentration and time dependent manner with IC₅₀ of 50 μg/ml and 30 μg/ml for 24 h, 28 μg/ml and 22 μg/ml for 48 h and 25 μg/ml and 20 μg/ml for 72 h respectively. The fraction F-4 induced G1 cell cycle arrest, reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential and subsequent apoptosis. Apoptosis is indicated in terms of increased Bax/Bcl-2 ratio, enhanced Annexin-V positivity, caspase 8 activation and DNA fragmentation. The active molecule isolated from fraction F-4, oleanolic acid and urosolic acid inhibited cell proliferation of MCF-7 and MDA-MB-231 cells at IC₅₀ value of 7.5 μM and 7.0 μM respectively, whereas there is devoid of significant cell inhibiting activity in non-cancer originated cells, HEK-293. In both MCF-7 and MDA-MB-231, oleanolic acid and urosolic acid induced cell cycle arrest and apoptosis as indicated by significant increase in Annexin-V positive apoptotic cell counts.

Conclusion

Our results suggest that W. tomentosa extracts has significant anti-cancer activity against breast cancer cells due to induction of apoptosis pathway. Olenolic and urosolic acid are important constituent molecules in the extract responsible for anti-cancer activity of W. tomentosa.     

Cytotoxic sesquiterpene lactones from the leaves of Vernonia guineensis Benth. (Asteraceae)

Ethnopharmacological relevance

Vernonia guineensis Benth. (Asteraceae) preparations are used in folk medicine in Cameroon to treat a number of ailments, including prostate cancer and malaria, and is used as an anthelmintic, adaptogen and antidote. The aim of this study was to continue the validation of the activity of Vernonia guineensis Benth. extracts and isolated molecules against cancer cell lines following the previous isolation of an anti-prostate cancer sugar ester from the root extract.

Materials and methods

Acetone extracts of Vernonia guineensis Benth. leaves were tested for activity against 10 cancer cell lines (Breast—MDA-MB-231, Breast—MCF-7, Colon—HCT-116, Leukemia—HL-60, Lung—A549, Melanoma—A375, Ovarian—OVCAR3, Pancreas—Mia-paca, Prostate—PC-3 and Prostate—DU-145). The acetone extract was subjected to bioactivity guided fractionation. Anti-proliferation and clonogenic activity of the isolated compounds were tested. The WST-1 assay was used for the anti-proliferation activity, while the standard clonogenic test was used to determine the clonogenic activity.

Results

The acetone extract of Vernonia guineensis Benth. demonstrated in vitro activity ranging from IC₅₀ 4–26 μg/mL against the 10 cell lines. Activity guided fractionation of this extract yielded two sesquiterpene lactones, isolated for the first time from the genus Vernonia. The compounds were characterized using spectroscopic experiments, including a combination of 1D and 2D NMR data. Vernopicrin (1) and Vernomelitensin (2) demonstrated in vitro activity against human cancer cell lines with IC₅₀ ranging from 0.35–2.04 μM (P<0.05) and 0.13–1.5 μM (P<0.05), respectively, between the most and least sensitive cell lines for each compound. Vernopicrin was most active against the human melanoma (A375) cell line and least active against the lung cancer (A549) cell line, while Vernomelitensin was also most active against the human melanoma (A375) cell line and least active against the breast cancer (MCF-7) cell line. Both compounds also demonstrated anticlonogenic activity.

Conclusion

The cytotoxicity demonstrated by the crude extract and isolated sesquiterpenes against cancer cell lines highlights the medicinal potential of V. guineensis. The selective anti-proliferation and dose dependent anticlonogenic activities suggest that the identified sesquiterpenes could be potential antitumor agents.     

Cytotoxicity and modes of action of four Cameroonian dietary spices ethno-medically used to treat Cancers: Echinops giganteus, Xylopia aethiopica, Imperata cylindrica and Piper capense

Ethnopharmacological relevance.

Echinops giganteus, Imperata cylindrica, Piper capense and Xylopia aethiopica are four medicinal spices used in Cameroon to treat cancers.

Aim of the study

The above plants previously displayed cytotoxicty against leukemia CCRF-CEM and CEM/ADR5000 cell lines as well as human pancreatic MiaPaCa-2 cells. The present study aims at emphasizing the study of the cytotoxicity and the modes of action of the above plants on a panel of ten cancer cell lines including various sensitive and drug-resistant phenotypes. The study has been extended to the isolation of the bioactive constituents from Echinops giganteus.

Materials and methods

The cytotoxicity of the extracts was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect the activation of caspases 3/7, caspase 8 and caspase 9 in cells treated with the four extracts. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells, analysis of mitochondrial membrane potential (MMP) as well as measurement of reactive oxygen species (ROS).

Results

The four tested extracts inhibited the proliferation of all tested cancer cell lines including sensitive and drug-resistant phenotypes. Collateral sensitivity of cancer cells to the extract of Echinops giganteus was generally better than to doxorubicin. The recorded IC₅₀ ranges were 3.29 µg/mL [against human knockout clones HCT116 (p53^−/−) colon cancer cells] to 14.32 µg/mL (against human liver hepatocellular carcinoma HepG2 cells) for the crude extract from Echinops giganteus, 4.17 µg/mL (against breast cancer cells transduced with control vector MDA-MB231 cells) to 19.45 µg/mL (against MDA-MB-231 BCRP cells) for that of Piper capense, 4.11 µg/mL (against leukemia CCRF-CEM cells) to 30.60 µg/mL (against leukemia HL60AR cells) for Xylopia aethiopica, 3.28 µg/mL [against HCT116 (p53^−/−) cells] to 33.43 µg/mL (against HepG2 cells) for Imperata cylindica and 0.11 µg/mL (against CCRF-CEM cells) to 132.47 µg/mL (against HL60AR cells) for doxorubicin. The four tested extracts induced apoptosis in CCRF-CEM cells via the alteration loss of MMP whilst that of Piper capense also enhanced the production of ROS.

Conclusion

The studied plants are potential cytotoxic drugs that deserve more detailed exploration in the future, to develop novel anticancer drugs against sensitive and otherwise drug-resistant phenotypes.     

Anti-breast cancer effects and mechanisms of Xihuang pill on human breast cancer cell lines

Objective

To investigate the anti-breast cancer (BC) effects and mechanisms of action of Xihuang pill (XHP) by conducting in vitro experiments on human BC cell lines.

Methods

Two human BC cell lines (MCF-7 and MDA- MB231) were cultured and treated with XHP. Cell viability was detected using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry was used to measure the cell cycle and apoptosis. The cell cycle was analyzed with propidium iodide staining. Apoptosis was evaluated using the Annexin V-fluorescein isothiocyanate/propidium iodide method. Western blotting was used to analyze the expression of estrogen receptor (ER)-α and ER-β.

Results

XHP had growth-inhibitory effects on MCF-7 and MDA-MB231 cells with a half-maximal inhibitory concentration (IC50) of 10.14 mg/mL (MCF-7) and 8.98 mg/mL (MDA-MB231). Apoptosis was induced to some extent. Certain changes in the ER were caused. Upregulation of ER-α protein was found in MCF-7 cells. ER-β expression in MDA-MB231 cells was increased. Cell-cycle arrest was not observed in the two BC cell lines. ER-β expression in MCF-7 cells was unchanged. No ER-α expression was shown in MDA-MB231 cells.

Conclusion

These data suggest that XHP can affect cell viability and cause apoptosis, but that the cell cycle is not blocked. XHP has a certain impact on ER expression, but its mechanisms of action of anti-BC effects may not be due to regulation of ER expression.     

Tumoral cytotoxic and antioxidative phenylpropanoid glycosides in Smilax riparia A. DC

Ethnopharmacological relevance

Smilax riparia A. DC., known as “Niu-Wei-Cai” in China, is distributed through the south and middle of China. The roots and rhizomes of Smilax riparia have been used not only as traditional Chinese medicines (TCMs) for the treatment of bronchitis, lumbago of renal asthenia, traumatic injury, asthenia edema, and cancer but also as edible wild herbs in some areas of China.

Aim of the study

To identify the phytochemicals in the roots and rhizomes of Smilax riparia and to investigate their antioxidant activities and cytotoxicities toward several tumor cell lines.

Materials and methods

Four fractions and five phenylpropanoid glycosides were obtained from roots and rhizomes of Smilax riparia under bioassay-guided screenings. The structures of five compounds were elucidated by spectroscopic methods and compared with published data. We evaluated their antioxidant activities and their cytotoxicities on five cancer cell lines: human promyelocytic leukemia (HL-60), human hepatocellular carcinoma (SMMC-7721), human lung cancer (A-549), human breast cancer (MCF-7), and human colon cancer (SW480).

Results

Of the five glycosides, one new compound (3, smilaside P) was isolated from an EtOAc fraction. Compound 1 was cytotoxic toward HL-60, SMMC-7721, A-549, MCF-7, and SW480 (IC₅₀ 2.70, 3.80, 11.91, 3.79, and 3.93 μM, respectively). Moreover, compounds 1–3 showed moderate scavenging activities against the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical (IC₅₀ 339.58, 330.66, 314.49 μM, respectively).

Conclusions

Five phenylpropanoid glycosides were reported for the first time from this TCM. Each was studied, as observed here for the first time, in the cytotoxic experiments toward HL-60, SMMC-7721, and SW480 cell lines. Compound 1, bearing three feruloyl groups and three acetyl groups, had the greatest cytotoxicity toward the five tumor cell lines. Compounds 1–3 showed moderate antioxidant activities. All results reflect that compounds 1–3 are cytotoxic for a wide variety of cancer cell lines of differing tissue origins and that the cytotoxicities of these compounds may be related to their antioxidant activities.     

Antitumor effect of blister beetles: An ethno-medicinal practice in Karbi community and its experimental evaluation against a murine malignant tumor model

Ethnopharmacological importance

The blister beetles Epicauta hirticornis and Mylabris cichorii are used as a folk medicine by the Karbi tribe in Karbi Anglong district of Assam, India for the treatment of different human ailments, including cancer cases.

Aim of the study

It includes field survey related to zoo-therapeutic aspects of two blister beetles in Karbi community, isolation of bio-active compound and evaluation of its antitumor potential with possible mode of action against murine Ehrlich ascites carcinoma (EAC).

Materials and methods

The main bio-active compound of blister beetles was isolated from ethyl acetate extract and the structure was confirmed as cantharidin using NMR, IR, Mass and X-ray diffractometer. The effect of cantharidin on apoptosis, necrosis, autophagy and the apoptosis related signaling pathways were determined using different bioassays, including cell cycle analysis, mitochondrial membrane potential, western blot analysis of cytochrome c, caspases 9, 3/7 assays, and lactate dehydrogenase (LDH) assay.

Results

Cantharidin induced apoptosis, necrosis and autophagy cell death in EAC cells. The decrease in mitochondrial membrane potential was observed, which may help to release cytochrome c from mitochondria to cytosol. Cantharidin treatment caused up-regulation of caspases 9 and −3/7 and a decrease in LDH activity in EAC cells.

Conclusion

The major bioactive compound of these blister beetles is cantharidin which induces severe apoptosis in EAC cells involving mitochondrial intrinsic pathway. Cantharidin-mediated inhibition of LDH activity may lead to short supply of NAD⁺ and cut off energy and anabolic supply to cancer cells.     

γ-Sitosterol from Acacia nilotica L. induces G2/M cell cycle arrest and apoptosis through c-Myc suppression in MCF-7 and A549 cells

Ethnopharmacological relevance

Acacia nilotica is widely distributed in Asia. In India, it occupies an important place in the indigenous system of medicine against anti-inflammatory, antioxidant, cancers, and/or tumors.

Aim of the study

The purpose of this study is to investigate the inhibitory effect of Acacia nilotica leaves extract and γ-Sitosterol on cell proliferation, the apoptotic effect and cell cycle arrest in breast and lung cancer cells.

Materials and methods

GC–MS and HPLC were used to determine the chemical constituents of this extract and γ-Sitosterol respectively. Human MCF-7 and A549 cell lines were treated with Acacia nilotica extract and γ-Sitosterol. Cell viability was determined by MTT assay. Cell proliferation was determined by BrdU incorporation assay. Apoptosis was detected by cell morphologic observation through AO/EtBr staining, cell cycle analysis, and immunoblot analysis on the expression of protein associated with cell cycle arrest.

Results

Experimental results of bioactive compound analysis indicate that γ-Sitosterol, bioactive ingredients of Acacia nilotica extract. The IC₅₀ value of extract on MCF-7 and A549 cancer cells was 493.3 ± 15.2 and 696.6 ± 11.5 μg/ml, respectively. Acacia nilotica extract and γ-Sitosterol were inhibited the cell proliferation by 54.34 ± 1.8 and 42.18 ± 3.9% for MCF-7 and 58.26 ± 1.5 and 44.36 ± 3.05% for A549 cells. The percentage of apoptotic cells observed in the MCF-7 and A549 cell lines were increased to 42.46 and 36.8% of extract; 46.68 and 43.24% for γ-Sitosterol respectively. Flow cytometric analysis results demonstrate that cells were arrested at the G2/M phase and decrease the c-Myc expression.

Conclusions

This study demonstrates in vitro results, which support the ethnomedical use of γ-Sitosterol against cancer. Experimental results of this study suggest that γ-Sitosterol exerts potential anticancer activity through the growth inhibition, cell cycle arrest and the apoptosis on cancer cells.     

Protective effects of fraction 1a of polysaccharides isolated from Solanum nigrum Linne on thymus in tumor-bearing mice

Aim of the study

To further screen out the anti-tumor active compound of polysaccharides isolated from Solanum nigrum Linne (SNL-P), which had shown to have anti-cervical cancer and modulating properties, and evaluate the thymus protective effects of this active compound.

Material and methods

SNL-P was separated and purified by column chromatography, and its anti-cervical cancer activity was evaluated by mice models injected of ascites U14 cells. Furthermore, the protective effect of fraction 1a of SNL-P (SNL-P1a) on the thymus tissue of tumor-bearing mice was evaluated by histological study and TUNEL staining. Finally, the protein expression of Bcl-2 and Bax gene were assayed by immunohistochemistry.

Results

SNL-P1a has shown a marked inhibition effect on U14 cevical cancer, it restore the ratio of CD4⁺/CD8⁺ peripheral blood T-lymphocyte subpopulation. Histological study and TUNEL staining results showed that SNL-P1a protect thymus tissue against the onslaught of tumor by inhibiting thymus lymphocyte apoptosis, and immunohistochemistry assay displayed that SNL-P1a treatment could increase Bcl-2/Bax ratio in thymus lymphocytes of tumor-bearer, which might promote more thymus lymphocytes towards proliferation.

Conclusion

SNL-P1a had significant growth inhibition effect on U14 cervical cancer and protective effect on thymus tissue of tumor-bearing mice.     

In vitro anti-prostate cancer and ex vivo antiangiogenic activity of Vernonia guineensis Benth. (Asteraceae) tuber extracts

Ethnopharmacological relevance

Prostate cancer is a major problem worldwide and affects most men above the age of forty-five. Vernonia guineensis Benth. (Asteraceae) root decoction is used in folk medicine in Cameroon to treat a number of ailments including prostate cancer. The aim of this study was to provide a preliminary validation of the use of Vernonia guineensis Benth. extracts to treat prostate cancer by evaluating the in vitro activity of its crude extracts and isolated molecules on prostate cancer cells lines and effect on angiogenesis which is essential for growth and metastases of prostate cancer.

Materials and methods

Aqueous, dichloromethane and methanol extracts of Vernonia guineensis Benth. tubers were tested for activity against three prostate cancer cell lines (PC-3, DU-145 and AT3B-1). The dichloromethane extract was subjected to bioactivity guided fractionation. Anti-proliferation, clonogenic and antiangiogenic activity of the crude extracts and isolated compound were tested. The WST-1 assay was used for the anti-proliferation activity meanwhile the standard clonogenic test and the rat ring aorta assay were carried out to determine the clonogenic and antiangiogenic activity of tested products respectively.

Results

The aqueous and methanol extracts of Vernonia guineensis Benth. demonstrated weak activity against prostate cancer cell lines in vitro with IC₅₀ > 100 μg/mL. The dichloromethane extract was more potent with IC₅₀ of 56.233 ± 3.630 μg/ml and 67.316 ± 2.452 μg/ml against the DU-145 and PC-3 cell lines respectively. Activity guided fractionation of this extract yielded a Pentaisovalerylsucrose (1) isolated for the first time from a natural source to the best of our knowledge. Compound 1 demonstrated in vitro activity against the human prostate cancer cell lines PC-3 and DU-145 with IC₅₀ of 5.701 ± 0.142 μM and 4.275 ± 0.710 μM, respectively. The IC₅₀ of the compound was 5.763 ± 0.425 μM against AT3B-1, a rat prostate cancer cell line expressing P-glycoprotein which is linked to drug resistance in most metastatic cancers. Compared to compound 1, Paclitaxel and Docetaxel were active against AT3B-1 at 2.641 ± 1.253 μM and 0.613 ± 0.251 μM. Paclitaxel showed IC₅₀ values of 0.004 ± 0.002 μM and 0.003 ± 0.001 μM against DU-145 and PC-3 prostate cancer cell lines respectively. Docetaxel showed IC₅₀ values of 0.002 ± 0.001 μM and 0.004 ± 0.001 μM against DU-145 and PC-3 prostate cancer cell lines respectively.

Conclusion

The in vitro anti-prostate cancer and the antiangiogenic activity of Vernonia guineensis Benth. extracts and isolated compound support the use of the tubers of this plant for the treatment of prostate cancer.     

Water extract of Rheum officinale Baill. induces apoptosis in human lung adenocarcinoma A549 and human breast cancer MCF-7 cell lines

Ethnopharmacological relevance

Rheum officinale Baill. (Da Huang) is one of the herbs commonly used in traditional Chinese medicine formulae against cancer. The traditional decoction is similar to the water extract used in the present study.

Aim of the study

The water extract of Da Huang was investigated to see if it possesses anticancer effects through apoptotic pathways.

Materials and methods

Human lung adenocarcinoma A549 and human breast cancer MCF-7 cell lines were treated with different concentrations of Da Huang water extract at different time intervals. Growth inhibition was detected by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and colony formation assays; apoptosis was detected by cell morphologic analysis, DNA fragmentation analysis and COMET assay.

Results

Da Huang water extract was found to have significant growth inhibitory effects on both A549 and MCF-7 cell lines with IC₅₀ values 620 ± 12.7 and 515 ± 10.1 μg/ml, respectively. Growth inhibitory effects were dose- and time-dependent. A significant decrease in cell number, DNA fragmentation and single DNA strand breakages were observed in the Da Huang water extract treated A549 and MCF-7 cells.

Conclusions

This suggests that the water extract of Da Huang exerts potential anticancer activity through growth inhibition and apoptosis on MCF-7 and A549 cells lines.     

Anti-cancer activity of compounds from Bauhinia strychnifolia stem

Ethnopharmacological relevance

The stem and root of Bauhinia strychnifolia Craib (Fabaceae family) have been traditionally used in Thailand to treat fever, alcoholic toxication, allergy and cancer. An EtOH extract of Bauhinia strychnifolia showed good inhibitory activity against several cancer cell lines including HT-29, HeLa, MCF-7 and KB. As there has been no previous reports on chemical constituents of Bauhinia strychnifolia, this study is aimed to isolate the pure compounds with anti-cancer activity.

Materials and methods

Five pure compounds were isolated from EtOH extract of Bauhinia strychnifolia stem using silica gel, dianion HP-20 and sephadex LH-20 column chromatography and were tested for their cytotoxic effects against HT-29, HeLa, MCF-7 and KB cell lines using the Sulforhodamine B (SRB) assay.

Results

Among five compounds, 3,5,7,3′,5′-pentahydroxyflavanonol-3-O-α-l-rhamnopyranoside (2) possessed very potent activity against KB (IC₅₀=0.00054 μg/mL), HT-29 (IC₅₀=0.00217 μg/mL), MCF-7 (IC₅₀=0.0585 μg/mL) and HeLa cells (IC₅₀=0.0692 μg/mL). 3,5,7-Trihydroxychromone-3-O-α-l-rhamnopyranoside (3) also showed good activity against HT-29 (IC₅₀=0.02366 μg/mL), KB (IC₅₀=0.0412 μg/mL) and MCF-7 (IC₅₀=0.297 μg/mL), respectively. The activity of 2 (IC₅₀=0.00054 μg/mL) against KB cell was ten times higher than that of the positive control, Camptothecin (anti-cancer drug, IC₅₀=0.0057 μg/mL). All compounds did not show any cytotoxicity with normal cells at the concentration of 1 μg/mL.

Conclusion

This is the first report of compounds 2 and 3 on anti-cancer activity and based on the anti-cancer activity of extracts and pure compounds isolated from Bauhinia strychnifolia stem, it might be suggested that this plant could be useful for treatment of cancer.     

Identification of bioactive constituents of Ziziphus jujube fruit extracts exerting antiproliferative and apoptotic effects in human breast cancer cells

Ethnopharmacological relevance

Ziziphus extracts have been used in Traditional Chinese Medicine for the treatment of cancer.

Aim of the study

In the present study we have investigated the effects of Ziziphus jujube extracts (ZEs) on breast cancer.

Materials and methods

We evaluated the effects of increasing concentrations of ZEs on ERα positive MCF-7 and ERα negative SKBR3 breast cancer cell proliferation using MTT assays. Apoptosis was analyzed by evaluating the involvement of some pro-apoptotic proteins, including Bax, Bad, Bid and PARP cleavage by immunoblotting analysis. Moreover, the effects of ZEs treatment on apoptosis were tested by both DNA fragmentation and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining. By using chromatographic techniques, we identified the constituents of the effective extracts.

Results

ZE1, ZE2, and ZE4 exerted significant antiproliferative effects on estrogen receptor alpha (ERα) positive MCF-7 (IC₅₀ values of 14.42, 7.64, 1.69 μg/mL) and ERα negative SKBR3 (IC₅₀ values of 14.06, 6.21, 3.70 μg/mL) human breast cancer cells. Remarkably, ZEs did not affect cell viability of both normal human fibroblasts BJ1-hTERT and nonmalignant breast epithelial MCF-10A cells. Treatment with ZEs induced cell death by apoptosis in both malignant breast cells. We found that the most effective extracts ZE2 and ZE4 shared a number of triterpenic acids, already known for their anticancer activities.

Conclusions

Our data provide a rational base for the use of Ziziphus extracts in the treatment of breast cancer in Traditional Chinese Medicine.     

Anti-tumor activity of Annona squamosa seeds extract containing annonaceous acetogenin compounds

Ethnopharmacological relevance

Seeds of Annona squamosa L. have been used in the south of China as a folk remedy to treat “malignant sores” (cancer).

Aim of the study

To investigate the chemical constituents and the anti-tumor activity of the standardized A. squamosa seeds extract in vitro and in vivo.

Materials and methods

Annonaceous acetogenin profiles of the standardized extract were determined by using Fourier transform infrared (FT-IR) and high performance liquid chromatography (HPLC) techniques. The anti-tumor activity of the extract was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cytotoxicity in vitro and H₂₂ hepatoma cells transplantation tumor model in vivo.

Results

The FT-IR spectroscopy showed the presence of annonaceous acetogenin compounds in the extract. Two major annonaceous acetogenins: 12, 15-cis-squamostatin-A and bullatacin were identified and quantified by HPLC. The seed extract showed significant anti-tumor activity against four human tumor cell lines, especially for MCF-7 (IC₅₀. 0.25 μg/ml) and Hep G2 (IC₅₀. 0.36 μg/ml) cells in vitro. The extract inhibited the growth of H₂₂ tumor cells in mice with a maximum inhibitory rate of 69.55% by oral administration.

Conclusion

A. squamosa seed extract showed significant anti-tumor activities against human hepatoma cells in vitro and in vivo, indicating a potential for developing the extract as a novel anti-liver cancer drug.     

Antibacterial and cytotoxic activity of isoprenylated coumarin mammea A/AA isolated from Mammea africana

Ethnopharmacological relevance

The stem bark of Mammea africana is widely distributed in tropical Africa and commonly used in traditional medicine. This study aims to identify the active compound in Mammea africana and to evaluate its antimicrobial and antiproliferative activity.

Materials and methods

Methanol extract from the bark of the Mammea africana was separated by liquid–liquid extraction, followed by open column chromatography. A principal antimicrobial compound was purified by high performance liquid chromatography (HPLC) and its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The antibacterial activity of the purified compound was determined using the broth microdilution method against 7 common pathogenic bacteria. The compound was also evaluated for cytotoxicity by cell proliferation assay (MTS) using the mouse embryonic fibroblast cell line NIH 3T3 and the non-small cell lung cancer cell line A549.

Results

The purified active compound was determined to be mammea A/AA and was found to be highly active against Campylobacter jejuni (MIC=0.5 μg/ml), Streptococcus pneumoniae (MIC=0.25 μg/ml), and Clostridium difficile (MIC=0.25 μg/ml). The compound exhibited significant antiproliferative activities against both NIH 3T3 and A549 cell lines.

Conclusion

Mammea A/AA isolated from Mammea africana exerts specific inhibitory activity against Campylobacter jejuni, Streptococcus pneumoniae, and Campylobacter difficile. Mammea A/AA was also found to exhibit significant cytotoxicity against both cancer and normal cell lines.     

Cytotoxicity and inhibition of P-glycoprotein by selected medicinal plants from Thailand

Ethnopharmacological relevance

Thai medicine has a long tradition of tonifying medicinal plants. In the present investigation, we studied the flower extracts of Jasminum sambac, Mammea siamensis, Mesua ferrea, Michelia alba, Mimusops elengi, and Nelumbo nucifera and speculated that these plants might influence metabolism and substance flow in the body.

Materials and methods

Isolation of porcine brain capillary endothelial cells (PBCECs) as well as multidrug-resistance CEM/ADR5000 leukemia cells, MDA-M;B-231 breast cancer, U-251 brain tumor, and HCT-116 colon cancer cells were used. The calcein-acetoxymethylester (AM) assay was used to measure inhibition of P-glycoprotein transport. XTT and resazurin assays served for measuring cytotoxicity.

Results

The extracts revealed cytotoxicity towards CCRF-CEM leukemia cells to a different extent. The strongest growth inhibition was found for the n-hexane extracts of Mammea siamensis and Mesua ferrea, and the dichloromethane extracts of Mesua ferrea and Michelia alba. The flower extracts also inhibited P-glycoprotein function in porcine brain capillary endothelial cells and CEM/ADR5000 leukemia cells, indicating modulation of the blood–brain barrier and multidrug resistance of tumors. Bioactivity-guided isolation of coumarins from Mammea siamensis flowers revealed considerable cytotoxicity of mammea A/AA, deacetylmammea E/BA and deacetylmammea E/BB towards human MDA-MB-231 breast cancer, U-251 brain tumor, HCT-116 colon cancer, and CCRF-CEM leukemia cells.

Conclusion

The plants analyzed may be valuable in developing novel treatment strategies to overcome the blood–brain barrier and multidrug-resistance in tumor cells mediated by P-glycoprotein.     

Estrogenic and serotonergic butenolides from the leaves of Piper hispidum Swingle (Piperaceae)

Ethnopharmacological relevance

Our previous work has demonstrated that several plants in the Piperaceae family are commonly used by the Q’eqchi Maya of Livingston, Guatemala to treat amenorrhea, dysmenorrhea, and pain. Extracts of Piper hispidum Swingle (Piperaceae), bound to the estrogen (ER) and serotonin (5-HT7) receptors.

Aim of the study

To investigate the estrogenic and serotonergic activities of Piper hispidum extracts in functionalized assays, identify the active chemical constituents in the leaf extract, and test these compounds as agonists or antagonists of ER and 5-HT7.

Materials and methods

The effects of the Piper hispidum leaf extracts were investigated in estrogen reporter gene and endogenous gene assays in MCF-7 cells to determine if the extracts acted as an estrogen agonist or antagonist. In addition, the active compounds were isolated using ER- and 5-HT7 receptor bioassay-guided fractionation. The structures of the purified compounds were identified using high-resolution LC–MS and NMR spectroscopic methods. The ER- and 5-HT7-agonist effects of the purified chemical constituents were tested in a 2ERE-reporter gene assay in MCF-7 cells and in serotonin binding and functionalized assays.

Results

Three butenolides including one new compound (1) were isolated from the leaves of Piper hispidum, and their structures were determined. Compound 1 bound to the serotonin receptor 5-HT₇ with IC₅₀ values of 16.1 and 8.3 μM, respectively, and using GTP shift assays, Compound 1 was found to be a partial agonist of the 5-HT₇ receptor. The Piper hispidum leaf extracts, as well as Compounds 2 and 3 enhanced the expression of estrogen responsive reporter and endogenous genes in MCF-7 cells, demonstrating estrogen agonist effects.

Conclusions

Extracts of Piper hispidum act as agonists of the ER and 5-HT₇ receptors. Compound 1, a new natural product, identified as 9,10-methylenedioxy-5,6-Z-fadyenolide, was isolated as the 5-HT₇ agonist. Compounds 2 and 3 are reported for the first time in Piper hispidum, and identified as the estrogen agonists. No inhibition of CYP450 was observed for any of these compounds in concentrations up to 1 μM. These activities are consistent with the Q’eqchi traditional use of the plant for the treatment of disorders associated with the female reproductive cycle.     

Cytotoxicity and modes of action of five Cameroonian medicinal plants against multi-factorial drug resistance of tumor cells

Ethnopharmacological relevance

Beilschmiedia acuta Kosterm, Clausena anisata (Willd) Hook, Fagara tessmannii Engl., Newbouldia laevis Seem., and Polyscias fulva (Hiern) Harms. are medicinal plants used in Cameroonian traditional medicine in the treatment of various types of cancers. The present study aims at investigating 11 methanolic extracts from the above Cameroonian medicinal plants on a panel of human cancer cell lines, including various drug-resistant phenotypes. Possible modes of action were analyzed for two extracts from Beilschmiedia acuta and Polyscia fulva and alpha-hederin, the representative constituent of Polyscia fulva.

Materials and methods

Cytotoxicity was determined using a resazurin assay. Cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were measured by flow cytometry. Cellular response to alpha-hederin was investigated by a mRNA microarray approach.

Results

Prescreening of extracts (40 µg/mL) showed that three of eleven plant extracts inhibited proliferation of CCRF-CEM cells by more than 50%, i.e. BAL (73.65%), the bark extract of Beilschmiedia acuta (78.67%) and PFR (68.72%). Subsequent investigations revealed IC₅₀ values below or around 30 µg/mL of BAL and PFR in 10 cell lines, including drug-resistant models, i.e. P-glycoprotein-overexpressing CEM/ADR5000, breast cancer resistance protein-transfected MDA-MB-231-BCRP, TP53 knockout cells (HCT116 p53^−/−), and mutation-activated epidermal growth factor receptor-transfected U87MG.ΔEGFR cells. IC₅₀ values below 5 µg/mL of BAL were obtained for HCT116 (p53^−/−) cells. IC₅₀ values below 10 µM of alpha-hederin were found for sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 cells. The BAL and PFR extracts induced cell cycle arrest between G0/G1 and S phases. PFR-induced apoptosis was associated with increased ROS generation and MMP breakdown. Microarray-based cluster analysis revealed a gene expression profile that predicted cellular response to alpha-hederin.

Conclusion

BAL, PFL and alpha-hederin, an exemplarily taken constituent of Beilschmiedia acuta and Polyscia fulva extracts revealed cytotoxicity towards cancer cell lines. Hence, Beilschmiedia acuta and Polyscia fulva may be valuable to develop drugs against otherwise drug-resistant cancer cells.