Antitumor activity ofTrichosanthes kirilowii

In Silico Molecular Docking Analysis, Cytotoxicity, and Antibacterial Activities of Constituents of Fruits of Cucumis dipsaceus

Cucumis dipsaceus (Cucurbitaceae) is a plant traditionally used against diarrhea, teeth-ach, wounds, stomach ache, meningitis, and cancer. The extracts of C. dipsaceus after silica gel column chromatography gave nine compounds identified using spectroscopic methods such as hexacosane (1), octadecane (2), 17-(-5-ethyl-2,6-dihydroxy-6-methylhept-3-en-2-yl)-9-(hydroxymethyl)-13-methylcyclopenta[α]phenanthren-3-ol (3), erythrodiol (4), (9,12)-propyl icosa-9,12-dienoate (5), α-spinasterol (6), 16-dehydroxycucurbitacin (7), cucurbitacin D (8), and 23,24-dihydroisocucurbitacin D (9). Compounds 3 and 4 are new to the genus Cucumis. α-Spinasterol showed better inhibition zone diameter = 13.67 ± 0.57, 15.00 ± 0.10, and 13.33 ± 0.57 mm against Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pyogenes compared with the other tested samples. α-Spinasterol (-8.0 kcal/mol) and 3 (-7.6 kcal/mol) displayed high binding affinity against DNA Gyrase compared to ciprofloxacin (-7.3 kcal/mol). α-Spinasterol and 16-dehydroxycucurbitacin showed better binding affinity against protein kinase. The cytotoxicity results revealed that the EtOAc extract showed the highest potency with IC50 = 16.05 μg/mL. 16-Dehydroxycucurbitacin showed a higher binding affinity (-7.7 kcal/mol) against human topoisomerase IIβ than etoposide. The cytotoxicity and antibacterial activities and in silico molecular docking analysis displayed by the constituents corroborate the traditional use of the plant against bacteria and cancer.

Root Extract of Trichosanthes kirilowii Suppresses Metastatic Activity of EGFR TKI-Resistant Human Lung Cancer Cells by Inhibiting Src-Mediated EMT

The roots of Trichosanthes kirilowii (TK) have been used in traditional oriental medicine for the treatment of respiratory diseases. In this study, we investigated whether an ethanolic root extract of TK (ETK) can regulate the metastatic potency of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-resistant human lung cancer cells. The relative migration and invasion abilities of erlotinib-resistant PC9 (PC9/ER) and gefitinib-resistant PC9 (PC9/GR) cells were higher than those of parental PC9 cells. Mesenchymal markers were overexpressed, whereas epithelial markers were downregulated in resistant cells, suggesting that resistant cells acquired the EMT phenotype. ETK reduced migration and invasion of resistant cells. The expression levels of N-cadherin and Twist were downregulated, whereas Claudin-1 was upregulated by ETK, demonstrating that ETK suppresses EMT. As a molecular mechanism, Src was dephosphorylated by ETK. The anti-metastatic effect of ETK was reduced by transfecting PC9/ER cells with a constitutively active form of c-Src. Dasatinib downregulated N-cadherin, Twist, and vimentin, suggesting that Src regulates EMT in resistant cells. Notably, CuB played a key role in mediating the anti-metastatic activity of ETK. Collectively, our results demonstrate that ETK can attenuate the metastatic ability of EGFR-TKI-resistant lung cancer cells by inhibiting Src-mediated EMT.

Recent Advances in the Application of Cucurbitacins as Anticancer Agents

Cucurbitacins are tetracyclic triterpenoid secondary metabolites, widely distributed in the Cucurbitaceae family. These bitter-tasting compounds act primarily as defense mechanisms against external injuries, and thus against herbivores, and furthermore, they have also found use in folk medicine in the treatment of various diseases. Many studies have acknowledged significant biological activities of cucurbitacins, such as antioxidant and anti-inflammatory activities, antimicrobial properties, or antitumor potential. Overall, cucurbitacins have the ability to inhibit cell proliferation and induce apoptosis in various cancer cell lines. Both in vitro and in vivo studies were performed to evaluate the anticancer activity of varied cucurbitacins. Cucurbitacins offer a promising avenue for future cancer treatment strategies, and their diverse mechanisms of action make them attractive candidates for further investigation. The aim of the present study is to shed light on the chemical diversity of this group of compounds by providing the sources of origin of selected compounds and their chemical structure, as well as insight into their anticancer potential. In addition, within this paper molecular targets for cucurbitacins and signalling pathways important for cancer cell proliferation and/or survival that are affected by the described class of compounds have been presented.

Cucurbitane-type triterpenoids from the fruits of Citrullus colocynthis

A phytochemical investigation of the fruits of Citrullus colocynthis resulted in the isolation of 21 structurally diverse cucurbitane triterpenoids, including 9 previously undescribed ones, colocynins A-I (1-9). Their absolute configurations were elucidated by means of quantum chemical electronic circular dichroism (ECD) calculations, CD exciton chirality method, and single-crystal X-ray crystallography. Colocynins A-C (1-3) represent the first examples of nonanorcucurbitane-type triterpenoids. An anti-acetylcholinesterase activity assay showed that 6, 10, 13, 18, and 20 exhibited inhibitory activities, with IC₅₀ values ranging from 5.0 to 21.7 μM. In addition, 18 and 21 showed significant cytotoxicity against PACA, A431, and HepG2 cells, with IC₅₀ values ranging from 0.042 to 0.60 and 3.6-14.4 μM, respectively.

Cucurbitane triterpenes from Hemsleya chinensis tubers and their anti-inflammatory activities

Six new cucurbitane-type triterpenes, hemchinins A-F (1-6), together with thirteen known ones (7-19) were isolated from ethyl acetate extraction of Hemsleya chinensis tubers. Compounds 1-2 were a group of cucurbitane triterpenes possessing an infrequent pentacyclic framework. Their structures were established by comprehensive UV, IR, HRMS, 1D/2D NMR, and ECD analyses. Bioassay results showed that most isolated compounds exhibited anti-inflammatory actions, in which compounds 13 and 15 exhibited stronger activities at 6.25 μM, with NO inhibition rates of 49.00 ± 0.05% and 48.40 ± 0.10%, respectively.

Development and Validation of a New Analytical HPLC-PDA Method for Simultaneous Determination of Cucurbitacins B and D from the Roots of Trichosanthes kirilowii

Trichosanthes kirilowii, one of the herbal formulas named SH003, has been used for treatment in traditional medicine. This paper aimed to analyze the marker compounds from the roots of T. kirilowii and evaluate a validation method for cucurbitacins B and D using high-performance liquid chromatography-photodiode array detector (HPLC-PDA). Two marker compounds were identified as cucurbitacin B (1) and cucurbitacin D (2) from the roots of T. kirilowii by spectroscopic analyses. Cucurbitacins B and D peaks were well separated and were detected at 15.4 min and 12.4 min, respectively, by a UV detector at 230 nm with the linearity (R2 > 0.999) range between 5 and 250 μg/mL, limit of detections (LODs) were 1.87 μg/mL and 1.30 μg/mL, respectively, while limit of quantifications (LOQs) were 5.66 μg/mL and 3.93 μg/mL, respectively. The established method offered good precision with overall intra- and inter-day variations of 0.34–1.26 and 0.26–1.35%, respectively, for % relative standard deviation (RSD, acceptance limit %RSD <3%). The cucurbitacins B and D recoveries ranged from 99.2 to 101.7% and 98.6 to 102.0%, respectively. These results suggest that cucurbitacins B and D could be a valuable candidate for marker compounds of the extract from T. kirilowii, and the proposed method was shown applicability for quality control of SH003.

The Ethanolic Extract of Trichosanthes Kirilowii Root Exerts anti-Cancer Effects in Human Non-Small Cell Lung Cancer Cells Resistant to EGFR TKI

The aim of this study was to investigate whether the ethanol extract of the Trichosanthes kirilowii root (ETK), traditionally used to treat lung diseases, exhibits anticancer activity in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-resistant non-small cell lung cancer (NSCLC) cells. ETK treatment suppressed the growth of EGFR TKI-resistant NSCLC cells, including H1299, H1975, PC9/ER (erlotinib-resistant PC9) and PC9/GR (gefitinib-resistant PC9) cells, in a concentration- and time-dependent manner. Dose-dependent decline in anchorage-dependent and -independent colony formation was also detected following ETK treatment. We demonstrate that the growth-inhibitory effect of ETK was related to apoptosis induction, based on flow cytometry results showing ETK-induced increase in the percentage of cells with sub-G1 DNA and the population of annexin V-positive cells. Consistently, ETK induced chromatin condensation and cleavage of poly(ADP-ribose) polymerase (PARP). As a molecular mechanism, the phosphorylation level of signal transducer and activator of transcription 3 (STAT3) and Src was decreased by ETK. ETK-induced apoptosis was partially reversed by transfection of constitutively activated STAT3, indicating that STAT3 inactivation mediated ETK-induced apoptosis in EGFR TKI-resistant NSCLC cells. Our results provide basic evidence supporting the role of ETK as a novel therapeutic in EGFR TKI-resistant NSCLC.

Bioassay-guided isolation of cytotoxic constituents from the flowers of Aquilaria sinensis

Bioassay-guided fractionation of the EtOH extract from the flowers of Aquilaria sinensis (Lour.) Spreng. (Thymelaeaceae) led to the isolation of a new cucurbitane-type triterpenoid, aquilarolide A (1), along with five known compounds (2-6). The structure of 1 was elucidated by extensive 1D and 2D nuclear magnetic resonance (NMR) experiments and mass spectrometry (MS) data and theoretical calculations of its electronic circular dichroism (ECD) spectra. Aquilarolide A, cucurbitacin E (3), cucurbitacin B (4), and 7-hydroxy-6-methoxy-2-[2-(4-methoxyphenyl)ethyl]-4H-1-benzopyran-4-one (6) showed significant cytotoxicity against human lung adenocarcinoma SPC-A-1, human lung squamous cell carcinoma NCI-H520, human lung adenocarcinoma A549, and paclitaxel-resistant A549 (A549/Taxol) cell lines. All four active compounds, with IC₅₀ values ranging from 0.002 to 0.91 μM, had better inhibitory activities against A549/Taxol cells than paclitaxel (IC₅₀ = 1.80 μM). Among them, cucurbitacin E (IC₅₀ = 0.002 μM) is the most active. Further studies are needed to evaluate their in vivo antitumor activities and to clarify their mechanisms.

Analysis of Active Compounds Using Target Protein Cofilin―Cucurbitacins in Cytotoxic Plant Bryonia cretica

We examined a two-step target protein binding strategy that uses cofilin as the target protein to analyze the active constituents in Bryonia cretica. In the first step, we prepared the target protein, and used it to analyze the compounds binding to it in the second step. We used the methanolic extract of B. cretica as a library of possible active compounds. We conducted LC–MS analysis using information from our previous study. The peaks in the HPLC profile were identified as cucurbitacin D, isocucurbitacin D, and cucurbitacin I. As far as we know, there is no known study of the activity of isocucurbitacin D in this research field. Therefore, we examined the effects of isocucurbitacin D on cell proliferation and cofilin protein in human fibrosarcoma cell line HT1080 to confirm the effectiveness of this strategy. The cytotoxicity assay, the fibrous/globular actin ratio assay, and the immunoblotting analysis revealed that isocucurbitacin D showed a cytotoxic effect with disruption of target protein cofilin. The target protein binding strategy is a direct and straightforward method for finding new drug seeds from crude sources, such as natural plant extracts.

New triterpenoid saponin glycosides from the fruit fibers ofTrichosanthes cucumerinaL

Five new triterpenoid saponin glycosides, trichocucumerisides A–E (1–5), together with eleven known compounds (6–16) were isolated from Trichosanthes cucumerina fruit fibers. The structures of the new compounds were elucidated by detailed analysis of NMR and mass spectroscopic data as well as chemical reactions. The anti-inflammatory study against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells shows that compounds 7 and 9 exhibited stronger NO inhibitory activity, with IC₅₀ values of 3.0 and 2.7 μM, respectively, with comparison to positive references Celecoxib and aminoguanidine (IC₅₀ values 75.7 and 75.0 μM, respectively). Compounds 7 and 9 also possessed a greater selectivity index (SI) of approximately 3–4-fold activity than that of the positive references.

The new glycosides 1–5, together with eleven known compounds were isolated. Two compounds exhibited more potent anti-inflammatory activity than Celecoxib and aminoguanidine reference compounds.

A Bioreductive Prodrug of Cucurbitacin B Significantly Inhibits Tumor Growth in the 4T1 Xenograft Mice Model

Cucurbitacin B (CuB), a highly cytotoxic constituent of the Cucurbitaceae plant, was identified to exhibit potent inhibitory activity against human cancer cells as well as normal cells. This disadvantage hampers the possibility of developing this compound into an anticancer drug candidate. In this work, several bioreductive prodrugs of CuB were designed to reduce toxicity to normal cells while maintaining the cytotoxic effect to cancer cells. Embedded with a bioreductive delivery and cleavable system in cancer tissues, cucurbitacin B-based prodrugs 1, 2, and 3 were synthesized and evaluated by in vitro and in vivo experiments. Compared with the parent CuB, prodrug 1 was found to significantly reduce the toxicity down to 310-fold lower against noncancerous cells. LC-MS analyses show that prodrug 1 efficiently releases the parent compound in the reductase-overexpressed MCF-7 cells. In addition, prodrug 1 shows satisfactory and comparable effectiveness in controlling tumor growth as that by tamoxifen in the 4T1 xenograft mice model.

Trichosanthis Fructus: botany, traditional uses, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Trichosanthis Fructus (ripe fruits of Trichosanthes kirilowii Maxim. and Trichosanthes rosthornii Harms) is an essential traditional Chinese medicine to treat thoracic obstruction, angina, cardiac failure, myocardial infarction, pulmonary heart disease, some cerebral ischaemic diseases, etc. The present report reviews the advancements in research on the botany, traditional uses, phytochemistry and pharmacology of Trichosanthis Fructus. Finally, perspectives on future research and its possible directions are discussed.

AIM OF THE STUDY

This review provides up-to-date information about the botany, traditional uses, phytochemistry, pharmacology, toxicity and quality control of Trichosanthis Fructus and discusses the perspectives on future research and possible directions of this traditional Chinese Medicine and its origin plants.

MATERIALS AND METHODS

The information on Trichosanthes kirilowii Maxim. and Trichosanthes rosthornii Harms was collected from published scientific materials, including books; monographs on medicinal plants; pharmacopoeia and electronic databases such as SCI finder, PubMed, Web of Science, ACS, Science Direct, Wiley, Springer, Taylor, CNKI and Google Scholar.

RESULTS

Approximately 162 compounds, including terpenoids, phytosterols, flavonoids, nitrogenous compounds and lignans, have been isolated and identified from Trichosanthes kirilowii Maxim. and Trichosanthes rosthornii Harms. Numerous studies have shown that the extracts and compounds isolated from these two plants exhibit pharmacological activities, including protection against myocardial ischaemia, calcium antagonist, endothelial cell protection, anti-hypoxic, anti-platelet aggregation, expectorant, anti-inflammatory, cytotoxic and antioxidant.

CONCLUSIONS

Trichosanthis Fructus is an essential traditional Chinese medicine with pharmacological activities that mainly affect the cardiovascular system. This review summarises its botany, traditional uses, phytochemistry and pharmacology. Future research is needed to clarify the different uses of the seeds, pericarps and fruits. Quality control of investigations of the fruits should be improved, and the potential uses of the flesh, leaves and twigs should be further explored.

Bioassay-guided isolation and identification of cytotoxic compounds from Bolbostemma paniculatum

ETHNOPHARMACOLOGICAL RELEVANCE

Bolbostemma paniculatum (Maxim.) Franquet (B. paniculatum), also named "Tu-bei-mu" in Chinese folk medicines, has been described in application for the treatment of tumors, warts, inflammation and toxication in traditional Chinese medicinal books. The major constituents in B. paniculatum are triterpenoid saponins, which have been proved to possess dramatically cytotoxic activity and antivirus activity. The aim of this study is to isolate and identify the active triterpenoid saponin from the bulb of B. paniculatum by a bioassay-guided method.

MATERIALS AND METHODS

Four cucurbitacine triterpenoid sapogenins and 11 triterpenoid saponins were isolated from the active EtOAc and n-BuOH extract of B. paniculatum by using bioassay-guided screening. Their structures were elucidated based on the spectroscopic methods and compared with published data. Cytotoxic activities of isolated compounds were determined by MTT assay.

RESULTS

Four cucurbitacine triterpenoid sapogenins, isocucurbitacin B(1), 23,24-dihydroisocucurbitacin B(2), cucurbitacin E(3), 23,24-dihydrocucurbitacin E(4), and 11 triterpenoid saponins, tubeimosideI(5), tubeimoside III(6), tubeimoside V(7), dexylosyltubeimoside III(8), lobatoside C(9), tubeimoside A(10), tumeimoside B(11), lobatoside A(12), tubeimoside C(13), tubeimoside IV(14), 7β,18,20,26-tetrahydroxy-(20S)-dammar-24E-en-3-O-α-L-(4-acetyl)arabinopyranosyl-(1→2)-β-D-glucopyranoside(15) were isolated from the active EtOAc and n-BuOH extracts. Of them, compounds 2, 4, 9 and 12 were firstly isolated from the Bolbostemma genus. MTT assay revealed that compounds 1, 3 and 4 had significantly activities against HeLa and HT-29 human cancer cells with IC50 values ranging from 0.93 to 9.73μM. It is worth mentioning that compound 4׳s activities against the two cell lines are 12- and 8-fold that of the positive control drug (5-Fu). Whereas, the cyclic bisdesmosides 5-9 exerted significantly activities on BGC-823, HeLa, HT-29 and MCF-7 cancer cells with IC50 values ranging from 1.30 to 15.64μM. And 6׳s activities against the four cell lines are 6-, 3-, 10- and 16-fold that of 5-Fu and 8׳s activities against the four cell lines are 5-, 3-, 14- and 9-fold that of 5-Fu.

CONCLUSION

The cytotoxic activity of the bulbs of B. paniculatum is mainly ascribable to cucurbitacine triterpenoid sapogenins (1-4) and the cyclic bisdesmosides (5-9). The cyclic bisdesmosides are the main anti-cancer active compounds of B. paniculatum. The above results provide scientific evidence to support, to some extent, the ethnomedicinal use of B. paniculatum as anticancer remedies in traditional Chinese medicine.

Multi-channel counter-current chromatography for high-throughput fractionation of natural products for drug discovery

A multi-channel counter-current chromatography (CCC) method has been designed and fabricated for the high-throughput fractionation of natural products without complications sometimes encountered with other conventional chromatographic systems, such as irreversible adsorptive constituent losses and deactivation, tailing of solute peaks and contamination. It has multiple independent CCC channels and each channel connects independent separation column(s) by parallel flow tubes, and thus the multi-channel CCC apparatus can achieve simultaneously two or more independent chromatographic processes. Furthermore, a high-throughput CCC fractionation method for natural products has been developed by a combination of a new three-channel CCC apparatus and conventional parallel chromatographic devices including pumps, sample injectors, effluent detectors and collectors, and its performance has been displayed on the fractionation of ethyl acetate extracts of three natural materials Solidago canadensis, Suillus placidus, and Trichosanthes kirilowii, which are found to be potent cytotoxic to tumor cell lines in the course of screening the antitumor candidates. By combination of biological screening programs and preparative high-performance liquid chromatography (HPLC) purification, 22.8 mg 6 beta-angeloyloxykolavenic acid and 29.4 mg 6 beta-tigloyloxykolavenic acid for S. canadensis, 25.3mg suillin for S. placidus, and 6.8 mg 23,24-dihydrocucurbitacin B for T. Kirilowii as their major cytotoxic principles were isolated from each 1000 mg crude ethyl acetate extract. Their chemical structures were characterized by electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance. The overall results indicate the multi-channel CCC is very useful for high-throughput fractionation of natural products for drug discovery in spite of the solvent balancing requirement and the lower resolution of the shorter CCC columns.

23,24-Dihydrocucurbitacin B induces G2/M cell-cycle arrest and mitochondria-dependent apoptosis in human breast cancer cells (Bcap37)

23,24-Dihydrocucurbitacin B (DHCB), a cucurbitacin-derived compound known to posses anticancer and anti-inflammatory activities. In this study, DHCB, isolated from roots of Trichosanthes kirilowli which is a traditional Chinese herb medicine used as treatments for cancer and other diseases, has been found to inhibit the proliferation of human cancer cell lines Bcap37, HeLa, SW620, SMMC-7721, K562 and MCF-7 in a dose- and time-dependent manner, and induce apoptosis in human breast cancer cell line Bcap37 at low concentration. DHCB-induced Bcap37 apoptosis was characterized with the changes in nuclear morphology, DNA fragmentation, activation of caspase-like activities, poly(ADP-ribose) polymerase cleavage, release of cytochrome c into cytosol. The cell death was partly prevented by a caspase-family inhibitor Z-VAD-FMK. The results suggest that DHCB-induced Bcap37 apoptosis through mitochondrial dependent pathway. Flow cytometric analysis revealed that at the lower dose of 1.8 and 3.6muM, DHCB-induced cancer cell lines death via an apoptotic process rather than necrotic one; whereas, the higher dose of 8.9, 17.9 and 35.7muM induced cell death via the necrotic process. Cell-cycle analysis demonstrated DHCB induction of G(2)/M phase cell-cycle arrest and apoptosis. The overall results suggest that DHCB might have the therapeutic value against human cancer cell lines, especially the breast cancer cell lines.

Cucurbitacins and cucurbitane glycosides: structures and biological activities

The natural cucurbitacins constitute a group of triterpenoid substances which are well-known for their bitterness and toxicity. Structurally, they are characterized by the tetracyclic cucurbitane nucleus skeleton, namely, 19-(10-->9beta)-abeo-10alpha-lanost-5-ene (also known as 9beta-methyl-19-norlanosta-5-ene), with a variety of oxygen substitutions at different positions. According to the characteristics of their structures, cucurbitacins are divided into twelve categories. The biological effects of the cucurbitacins are also covered.