Supercritical carbon dioxide extraction of ethyl p-methoxycinnamate from Kaempferia galanga L. rhizome and its apoptotic induction in human HepG2 cells

Ethyl cinnamate suppresses tumor growth through anti-angiogenesis by attenuating VEGFR2 signal pathway in colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Kaempferia galanga Linn. is an aromatic medicinal herb with extensively applied in India, China, Malaysia and other South Asia countries for thousands of years. It has been mentioned to treat abdominal tumors. Ethyl cinnamate (EC), one of the main chemical constituents of the rhizome of K. galanga, exhibited nematocidal, sedative and vasorelaxant activities. However, its anti-angiogenic activity, and anti-tumor effect have not been investigated.

AIM OF THE STUDY

To investigate the anti-angiogenic mechanism of EC and its anti-tumor effect by suppressing angiogenesis.

MATERIALS AND METHODS

The in vitro anti-angiogenic effect was evaluated using HUVECs model induced by VEGF and zebrafish model in vivo. The influence of the EC on phosphorylation of VEGFR2 and its downstream signaling pathways were evaluated by western blotting assay. Molecule docking technology was conducted to explore the interaction between EC and VEGFR2. SPR assay was used for detecting the binding affinity between EC and VEGFR2. To further investigate the molecular mechanism of EC on anti-angiogenesis, VEGFR2 knockdown in HUVECs and examined the influence of the EC. Anti-tumor activity of EC was evaluated using colony formation assay and apoptosis assay. The inhibitory effect of EC on tumor growth was explored using HT29 colon cancer xenograft model.

RESULTS

EC obviously inhibited proliferation, migration, invasion and tube formation of VEGF-induced HUVECs. EC also induced apoptosis of HUVECs. Moreover, it inhibited the development of vessel formation in zebrafish. Further investigations demonstrated that EC could suppress the phosphorylation of VEGFR2, and its downstream signaling pathways were altered in VEGF-induced HUVECs. EC formed a hydrogen bond to bind with the ATP binding site of the VEGFR2, and EC-VEGFR2 interaction was shown in SPR assay. The suppressive effect of EC on angiogenesis was abrogated after VEGFR2 knockdown in HUVECs. EC inhibited the colon cancer cells colony formation and induced apoptosis. In addition, EC suppressed tumor growth in colon cancer xenograft model, and no detectable hepatotoxicity and nephrotoxicity. In addition, it inhibited the phosphorylation of VEGFR2, and its downstream signal pathways in tumor.

CONCLUSIONS

EC could inhibit tumor growth in colon cancer by suppressing angiogenesis via VEGFR2 signaling pathway, and suggested EC as a promising candidate for colon cancer treatment.

Synthesis of molecularly imprinted polymer with a methacrylate derivative monomer for the isolation of ethyl p-methoxycinnamate as an active compound from Kaempferia galanga L. extracts

Kaempferia galanga rhizome is traditionally used as a treatment for various diseases. Ethyl p-methoxycinnamate (EPMC), which constitutes up to 31.77% of the total essential oil, is the main/marker compound. EPMC is responsible for various pharmacological activities of Kaempferia galanga rhizome. According to the existing research, the isolation yield of EPMC is still meager, namely 0.50-2.50%; thus, a new EPMC isolation method is needed to produce better results. In this study, after determining the association constant and obtaining the Jobs plot between methacrylate derivative monomers and EPMC, a molecularly imprinted polymer for solid phase extraction (MI-SPE) was synthesized through bulk polymerization with EPMC as a template, methacrylic acid as a monomer, TRIM/EDGMA as a crosslinker in a ratio of 1 : 4 : 20 (MIP1) or 1 : 7 : 20 (MIP2). BPO was used as an initiator and n-hexane was used as a porogen. The synthesis of the NIP was also conducted using the same ratio but without the template. The MIPs were then characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) measurements, and their analytical performance was evaluated through adsorption capacity and selectivity. The results indicate that MIP2 exhibits better analytical performance with an adsorption capacity value of 0.0813 mg g-1. The selectivity of MIP2 was tested using EPMC analog compounds, namely ethyl cinnamic (EC), cinnamaldehyde (CD), and kaempferol (KF), with imprinting factor (IF) values of 17.436, 1.539, and 0.06, respectively. Lastly, MIP2 was applied to the SPE cartridge for the isolation of EPMC from Kaempferia galanga rhizome extract, and showed a percentage recovery of 82.40% for the ethanol extract, 68.05% for the ethyl acetate extract, and 65.27% for the n-hexane extract. MI-SPE 2 gives high purity results for the ethanol, ethyl acetate, and n-hexane extracts, with purities of 97.00%, 97.63%, and 99.59%, respectively. These results indicate that the MI-SPE technique shows great potential as a new method for isolating EPMCs with high yield and purity.

Novel ethyl p-methoxy cinnamate rich Kaempferia galanga (L.) essential oil and its pharmacological applications: special emphasis on anticholinesterase, anti-tyrosinase, α-amylase inhibitory, and genotoxic efficiencies

Background

Kaempferia galanga (L.) is one of the prospective therapeutic plants with an aromatic rhizome, and belongs to the Zingiberaceae family. This herb is commonly used by local practitioners in traditional Asian medicine.

Methods

In the present investigation, the novel Kaempferia galanga rhizome essential oil rich in ethyl p-methoxy cinnamate (EMCKG) was evaluated using GC/MS for chemical composition analysis. EMCKG was analyzed for its possible antimicrobial, neurodegenerative inhibitory, acetylcholinesterase, anti-inflammatory, and antioxidant activities as well as for the genotoxic effects using the standard methodologies. ANOVA and post hoc was performed to test the statistical significance of the study.

Results

GC/MS analysis identified ethyl p-methoxy cinnamate as the major component of EMCKG essential oil with an area percentage of 66.39%. The EMCKG exhibited moderate (DPPH assay IC₅₀ = 15.64 ± 0.263 µg/mL; ABTS assay IC₅₀ = 16.93 ± 0.228 µg/mL) antioxidant activity than standard ascorbic acid (DPPH assay IC₅₀ = 21.24 ± 0.413 µg/mL; ABTS assay IC₅₀ = 21.156 ± 0.345 µg/mL). Similarly, EMCKG showed comparable activity in albumin denaturation (IC₅₀ = 2.93 ± 0.59 µg/mL) and protease inhibitor assay (IC₅₀ = 17.143 ± 0.506 µg/mL) to that of standard sodium diclofenac (IC₅₀ = 23.87 ± 0.729 µg/mL and IC₅₀ = 19.18 ± 0.271 µg/mL, respectively). The EMCKG exhibited a dose-dependent antimicrobial activity pattern with the highest inhibitory activity at 500 µg/mL against Staphylococcus aureus and considerable anticholinesterase activities (IC₅₀ = 21.94 ± 0.109 µg/mL) compared to the standard galanthamine (IC₅₀ = 27.18 ± 0.511 µg/mL). EMCKG also showed strong anti-diabetic activity (IC₅₀ = 18.503 ± 0.480 µg/mL) and anti-tyrosinase activity (IC₅₀ = 14.756 ± 0.325 µg/mL) as compared to the standards used (acarbose IC₅₀ = 20.39 ± 0.231 µg/mL and kojic acid IC₅₀ = 17.73 ± 0.192 µg/mL) in the study. Genotoxicity analysis of EMCKG revealed that at 1 µg/mL concentration has no toxic effects in mitosis of Allium cepa roots (Mitotic Index MI = 13.56% and chromosomal aberration CA = 07.60%). The ANOVA confirmed that except for the anticholinesterase activity, there is insignificant difference for essential oil and standards used for all the other bioactivities thus confirming their interchangeable applicability.

Conclusions

Current research provides the basis for the fact that besides being a rich source of ethyl p-methoxycinnamate, EMCKG has the potential for future formulation and development of an inexpensive skin-care agent and for the preparation of anti-diabetic drugs.

Synthesis and biological evaluation of 1,2,3-triazole hybrids of 4-methoxy ethyl cinnamate isolated from Hedychium spicatum (Sm) rhizomes: identification of antiproliferative lead actives against prostate cancer

A series of 1, 2, 3- triazole hybrids (9a-9n) were synthesised from major phenolic constituent, 4-methoxy ethyl cinnamate (5) isolated from rhizomes of Hedychium spicatum (Sm), a traditional medicinal plant used in variety of disease conditions. All the synthesised analogues were tested for their in vitro antiproliferative potential against HCT 116 (colon cancer), A549 (lung cancer), DU-145 (prostate cancer), Hep G2 (hepatoma) and HEK-293 (normal) cell lines. Among the compounds tested, compounds 9i and 9k potently arrested proliferation of DU-145 (prostate cancer) cell line. Compound 9i displayed 20 times better antiproliferative potential than parent compound and almost identical inhibitory activity to that of the standard drug, doxorubicin. The flow cytometric analysis revealed that 9i arrested cells in G2/M phase of cell cycle and induced apoptosis. Overall, the hybrid derivative 9i was found to be a potential antiproliferative lead against prostate cancer.

The industrially important genus Kaempferia: An ethnopharmacological review

Kaempferia, a genus of the family Zingiberaceae, is widely distributed with more than 50 species which are mostly found throughout Southeast Asia. These plants have important ethnobotanical significance as many species are used in Ayurvedic and other traditional medicine preparations. This genus has received a lot of scholarly attention recently as a result of the numerous health advantages it possesses. In this review, we have compiled the scientific information regarding the relevance, distribution, industrial applications, phytochemistry, ethnopharmacology, tissue culture and conservation initiative of the Kaempferia genus along with the commercial realities and limitations of the research as well as missing industrial linkages followed by an exploration of some of the likely future promising clinical potential. The current review provides a richer and deeper understanding of Kaempferia, which can be applied in areas like phytopharmacology, molecular research, and industrial biology. The knowledge from this study can be further implemented for the establishment of new conservation strategies.

Derivatives of Cinnamic Acid Esters and Terpenic Diversity in Volatiles of Thirty-Six Sand Ginger (Kaempferia galanga L.) Accessions of Eastern India Revealing Quality Chemovars

The essential oil of Kaempferia galanga L. commonly known as sand ginger has increased its demand in national and international market for decades. Cinnamic acid esters like ethyl-p-methoxy cinnamate (EPMC) and ethyl cinnamate (EC) are major constituents in its essential oil. In spite of the high demand for the plant as raw material, identification of quality chemovars having high essential oil (EO) yield and constituents is still at an infant stage. With this in mind, we have evaluated the EO yield of 36 accessions from three provinces of Eastern India, which varied within a range of 0.41 ± 0.01 to 2.63 ± 0.03 v/w. Further, a total of 65 compounds were detected by gas chromatography and mass spectrometry (GC-MS) with area percentages varying from 76.16 to 97.3%. EPMC was found to be the major component in 14 accessions with area percentages varying from 10.7% to 41.1%, whereas other 22 accessions showed EC as the major constituent, varying from 16% to 29.1%. Further, a diversity study among accessions was performed by agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) analysis based on the abundance of identified constituents, which categorized all 36 accessions into three clusters. Thus, the present study helps to identify quality chemovar K.g16 and K.g14 with respect to oil yield and constituents, respectively, which could be used to guide commercial cultivation and further improvement of the taxa.

Phytochemical characterization of the ethanolic extract of Kaempferia galanga rhizome for anti-oxidant activities by HPTLC and GCMS

Background

The rhizome of Kaempferia galanga (K. galanga) was collected from Meghalaya, India, and its ethanolic extract was obtained by freeze-drying or lyophilization process, which was then assessed for its in vitro anti-oxidant activity and phytochemical characterization using high-performance thin-layer chromatography (HPTLC) and gas chromatography-mass spectroscopy (GCMS).

Results

In vitro anti-oxidant activity analysis shows an inhibitory concentration (IC50) value of 1.824 mg/mL and 0.307 mg/mL for, α, α-diphenyl-ρ-picrylhydrazyl (DPPH) and 2, 2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays, respectively. Total polyphenol content (TPC) of 23.55 ± 0.5 mg gallic acid equivalent (GAE)/g dry weight of extract and total flavonoid content (TFC) of 100 ± 1.414 mg rutin equivalents (RE)/g dry weight of extract were found. High-performance thin-layer chromatography (HPTLC) analysis shows the best separation of bands at different retention factor (Rf) values, when employing the solvent system 2-butanol/1-propanol/water in the ratio of 3:1:1 (v/v/v). Gas chromatography-mass spectroscopy (GCMS) analysis confirms the presence and identification of various phytocompounds, with ethyl p-methoxycinnamate identified as the major active compound.

Conclusion

Freeze-dried ethanolic extract of K. galanga (rhizome) possesses anti-oxidant activity. Ethyl p-methoxycinnamate is present as the major bioactive component (about 94.87% of the total area composition), and since it has very important and diverse medicinal properties, a freeze-drying process (lyophilization) can be utilized for its isolation and extraction.

Kaempferia galanga L.: Progresses in Phytochemistry, Pharmacology, Toxicology and Ethnomedicinal Uses

K. galanga is an aromatic medicinal herb. It is locally to India and distributed in China, Myanmar, Indonesia, Malaysia, and Thailand. K. galanga is a Traditional Chinese Herb Medicine (TCHM), which has been applied to treat cold, dry cough, toothaches, rheumatism, hypertension and so on. In addition, it has been used widely as spices since its highly aromas. The aim of this review is to compile and update the current progresses of ethnomedicinal uses, phytochemistry, pharmacology and toxicology of K. galanga. All the data on K. galanga were based on different classical literary works, multiple electronic databases including SciFinder, Web of Science, PubMed, etc. The results showed that ninety-seven compounds have been identified from rhizome of K. galanga, including terpenoids, phenolics, cyclic dipeptides, flavonoids, diarylheptanoids, fatty acids and esters. Modern pharmacology studies revealed that extracts or secondary metabolites of the herb possessed anti-inflammatory, anti-oxidant, anti-tumorous, anti-bacterial, and anti-angiogenesis effects, which were closely related to its abundant ethnomedicinal uses. In conclusion, although previous research works have provided various information of K. galanga, more in-depth studies are still necessary to systemically evaluate phytochemistry, pharmacological activities, toxicity and quality control of this herb.

Biological Properties, Health Benefits and Enzymatic Modifications of Dietary Methoxylated Derivatives of Cinnamic Acid

Methoxylated derivatives of cinnamic acid play an important role in the formation of the pro-health potential of food products. Numerous reports present them as molecules with strong antimicrobial, antidiabetic, anticancer as well as hepato-, cardio-, and neuroprotective activities. In the last three decades, many research groups have tried to extend the practical application of these molecules as therapeutic and antioxidant agents extensively studying the methods of their lipophilization as the solution of problems of their low oral bioavailability and rapid metabolism. This article summarizes the latest data of natural sources of occurrence, biological potential and bioavailability of methoxy derivatives of cinnamic acids. Metabolism and pharmacokinetics of this group of dietary compounds are also extensively discussed as well as reviewing the methods of their chemical and enzymatic lipophilization in the aspect of their use in food and pharmaceutical industries.

Cytotoxic Activity of Ethyl-para-methoxycinnamate from Kaempferia galanga L. on A549 Lung Cancer and B16 Melanoma Cancer Cells

Kaempferia galanga L. belongs to the family of Zingiberaceae, an endangered medicinal plant with pharmacology activities. Ethyl-p-methoxycinnamate (EPMC) is an essential phytoconstituent of K. galanga rhizomes. Several studies have reported that EPMC has anticancer activities in several cancer cells, including CL-6 gallbladder cancer cells, HepG2liver cancer cells, MCF-7 breast cancer cells, and Raji lymphoma cancer cells. However, studies on A549 lung cancer and B16 melanoma cancer cells have not been reported. This study aimed to determine the anticancer activity of EPMC against A549 lung cancer and B16 melanoma cancer cells. EPMC was obtained by extraction using n-hexane, then recrystallized with chloroform. The isolate was then analyzed by thin-layer chromatography (TLC), and the structure was characterized by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Cytotoxic activity was determined under Presto Blue assay. Based on the result, EPMC from K. galanga showed the cytotoxic effect on B16 cells with an IC50 value of 97.09 μg/mL, whereas EPMC showed no significant cytotoxic effect on A549 with an IC50 value of 1407.75 μg/mL. It was concluded that EPMC has potential cytotoxic on B16 melanoma cancer cells, but it showed inactive activity against A549 lung cancer cells. Further molecular mechanism underlying EPMC cytotoxic activity needs to be conducted.

Interesterification of Egg-Yolk Phosphatidylcholine with p-Methoxycinnamic Acid Catalyzed by Immobilized Lipase B from Candida Antarctica

The p-methoxycinnamic acid (p-MCA) is one of the most popular phenylpropanoids, the beneficial impact of which on the human health is well documented in the literature. This compound has shown many valuable activities including anticancer, antidiabetic, and neuro- and hepatoprotective. However, its practical application is limited by its low bioavailability resulting from rapid metabolism in the human body. The latest strategy, aimed at overcoming these limitations, is based on the production of more stability in systemic circulation bioconjugates with phospholipids. Therefore, the aim of this research was to develop the biotechnological method for the synthesis of phospholipid derivatives of p-methoxycinnamic acid, which can play a role of new nutraceuticals. We developed and optimized enzymatic interesterification of phosphatidylcholine (PC) with ethyl p-methoxycinnamate (Ep-MCA). Novozym 435 and a binary solvent system of toluene/chloroform 9:1 (v/v) were found to be the effective biocatalyst and reaction medium for the synthesis of structured p-MCA phospholipids, respectively. The effects of the other reaction parameters, such as substrate molar ratio, enzyme dosage, and reaction time, on the degree of incorporation of p-MCA into PC were evaluated by use of an experimental factorial design method. The results showed that substrate molar ratio and biocatalyst load have significant effects on the synthesis of p-methoxycinnamoylated phospholipids. The optimum conditions were: Reaction time of three days, 30% (w/w) of Novozym 435, and 1/10 substrate molar ratio PC/Ep-MCA. Under these parameters, p-methoxycinnamoylated lysophosphatidylcholine (p-MCA-LPC) and p-methoxycinnamoylated phosphatidylcholine (p-MCA-PC) were obtained in isolated yields of 32% and 3% (w/w), respectively.

Phytochemistry, pharmacological activities and uses of traditional medicinal plant Kaempferia galanga L. - An overview

ETHNOPHARMACOLOGICAL RELEVANCE

Kaempferia galanga L. is a stemless, rhizomatous, aromatic, perennial and indigenous herb. It is native to India and distributed in China, Bangladesh, Myanmar, Sri Lanka, Japan, Thailand, Indonesia, Malaysia, Vietnam, Laos, Sudan, Nigeria and South Africa. It is an important Indian medicinal herb that has a long history of use in the treatment of several kinds of human ailments including vata ailments like cough and cold, fever, headache, pains disorders, skin diseases, rheumatic diseases, arthritis, joint fractures, vertigo, wounds, gastritis, antidote for snake venoms, inflammation, blood vomiting, mouth sores and tongue blisters in infants. Moreover, the rhizomes of this plant are highly aromatic and have been used widely as spices, in food flavoring, pickles, cosmetics and in perfumery products.

AIM OF THE REVIEW

This paper aimed to provide a critical review of current scenario on K. galanga. This review provides a current data on diversity, phytochemistry, pharmacological activities and traditional uses of K. galanga.

MATERIALS AND METHODS

The information and data on K. galanga were collated from various resources like ethnobotanical textbooks and literature databases such as PubMed, Science Direct, Wiley, Springer, Tailor and Francis, Scopus, Inflibnet, Google and Google Scholar.

RESULTS

The forty-nine phytochemicals including esters, terpenoids, flavonoids, thiourea derivatives, polysaccharides, diarylheptanoids, phenolic acids, phenolic glycoside and cyclic lipodepsipeptide have been hitherto isolated and characterized. The major bioactive compounds extracted from the rhizome of K. galanga were ethyl p-methoxycinnamate, ethyl cinnamate, kaempferol, kaempferide, kaempsulfonic acids, kaemgalangol A, xylose, cystargamide B and 3-caren-5-one. Various studies demonstrated that the K. galanga and its constituents possess several pharmacological activities like antimicrobial, antioxidant, amebicidal, analgesic, anti-inflammatory, anti-tuberculosis, anti-dengue, anti-nociceptive, anti-angiogenic, anticancer, hyperlipidemic, hypopigmentary, osteolysis, larvicidal, insecticidal and mosquito repellent, nematocidal, sedative, sniffing, vasorelaxant and wound healing.

CONCLUSION

Kaempferia galanga L. is a valuable medicinal plant which is used traditionally in India to treat a wide variety of ailments. A number of bioactive phytochemicals like esters, terpenoids, flavonoids, polysaccharides, diarylheptanoids, cyclic lipodepsipeptide, phenolic acids and glucoside have been isolated from the rhizomes of K. galanga by several researchers. These phytochemicals are highly bioactive and exhibit various pharmacological activities.

Cytotoxicity, Cell Cycle Arrest, and Apoptosis Induction Activity of Ethyl-p-methoxycinnamate in Cholangiocarcinoma Cell

Objective:

To investigate cytotoxic activity of ethyl-p-methoxycinnamate (EPMC) including its effect on p-glycoprotein (multidrug resistance-1: mdr-1 gene) in human cholangiocarcinoma cell.

Methods:

Cytotoxic activity of EPMC against human cholangiocarcinoma (CL-6), fibroblast (OUMS-36T-1F), and colon cancer (Caco-2) cell lines were assessed using MTT assay. Selectivity index (SI) was determined as the ratio of IC₅₀ (concentration that inhibits cell growth by 50%) of EPMC in OUMS-36T-1F and that in CL-6 cell. Cell cycle arrest and apoptosis in CL-6 cells were investigated by flow cytometry and fluorescent microscopy. Effect of EPMC on mdr-1 gene expression in CL-6 and Caco-2 was determined by real-time PCR.

Results:

The median (95% CI) IC₅₀ values of EPMC in CL-6, OUMS-36T-1F, and Caco-2 were 245.5 (243.1-266.7), 899.60 (855.8-966.3) and 347.0 (340.3-356.9) µg/ml, respectively. The SI value of the compound for the CL-6 cell was 3.70. EPMC at IC₅₀ inhibited CL-6 cell division and induced apoptosis compared to untreated control. EPMC exposure did not induce mdr-1 gene expression in both CL-6 and Caco-2 cells.

Conclusion:

The results suggest the potential role of EPMC in cholangiocarcinoma with a low possibility of drug resistance induction.

Structural Characterization and Antitumor Activity of Polysaccharides from Kaempferia galanga L

The water-soluble polysaccharides from Kaempferia galanga L. (KGPs) were extracted and purified, and their structural characteristics and antitumor activity were further investigated. The UV spectrum, high-performance gel permeation chromatography (HPGPC), Fourier-transform infrared spectroscopy (FTIR), and ion chromatography (IC) were employed to evaluate the structural characteristics, and H22 tumor-bearing mice model was established to demonstrate the antitumor activity. Physicochemical analysis and UV spectrum results showed that the proportions of total sugar, protein, and uronic acid in KGPs were 85.23%, 0.54%, and 24.17%, respectively. HPGPC, FTIR, and IC indicated that KGPs were acidic polysaccharides with skeletal modes of pyranose rings and mainly composed of arabinose and galactose with the average molecular weight of 8.5 × 105 Da. The in vivo antitumor experiments showed that KGPs could effectively protect the thymus and spleen of tumor-bearing mice from solid tumors and enhance the immunoregulatory ability of CD4+ T cells, the cytotoxic effects of CD8+ T cells and NK cells, and finally resulting in the inhibitory effects on H22 solid tumors. This study provided a theoretical foundation for the practical application of KGPs in food and medical industries.

Kaemgalangol A: Unusual seco-isopimarane diterpenoid from aromatic ginger Kaempferia galanga

A new unusual seco-isopimarane, kaemgalangol A (1) and 12 usual analogs (2-13) were isolated from the rhizomes of Kaempferia galanga (Family: Zingiberaceae). KaemgalangolA (1) represented a rarely isolated 9,10-seco-isopimarane skeleton. The chemical structures of the isolated compounds were mainlyinvestigated by spectroscopic techniques such as 1D, 2D NMR, and HRMS. The absolute configuration of 1-3 was studied by X-ray diffraction analysis as well as experimental and TDDFT-calculated electronic circular dichroism. Among the isolated diterpenoids, 5, 6 and 9 exhibited cytotoxic activity against HeLa (IC₅₀ 75.1, 74.2 and 76.5 μM, respectively) and HSC-2 (IC₅₀ 69.9, 53.3 and 58.2 μM, respectively) cancer cells.

Anticholangiocarcinoma activity and toxicity of the Kaempferia galanga Linn. Rhizome ethanolic extract

BACKGROUND

Cholangiocarcinoma (CCA) is an important public health problem in several tropical and subtropical parts of the world particularly Thailand. Chemotherapy of CCA is largely ineffective and discovery and development of effective alternative drugs is urgently needed. The objective of the study was to confirm the anti-CCA potential as well as toxicity of the crude extract of Kaempferia galangal Linn. (rhizome) both in vitro and in animal models.

METHODS

The ethanolic extract of K. galanga Linn. rhizome, ethyl-p-methoxycinnamate (EPMC) and 5-fluorouracil (5-FU) were evaluated for their cytotoxic activities against CCA cell line (CL-6) using MTT cell proliferation assay. Acute and subacute toxicity of the extract were evaluated in ICR (Imprinting Control Region) mice according to the OECD (International Organization for Economic Co-operation and Development) Guideline. Anti-CCA activity was evaluated in CCA- xenografted nude mice.

RESULTS

Results of cytotoxicity test showed moderate activity of the extract and EPMC with median (95% confidence interval: 95% CI) 50% inhibitory concentration (IC50) of 64.2 (57.76-72.11) and 49.19 (48.16-52.29) μg/ml, respectively. The IC50 of 5-FU was 107.1 (103.53-109.64) μg/ml. The selectivity index (SI) values for the extract, EPMC and 5-FU against human normal cell line (OUMS) and cancer cell line (CL-6) were 2.2, 2.09 and 1.31, respectively. Toxicity testing revealed no overt toxic effect up to the maximum single oral dose of 5000 mg/kg body weight and up to daily dose of 1000 mg/kg body weight for 30 days. The extract at the maximum tolerated dose level of 1000 mg/kg body weight for 30 days exhibited promising anti-CCA activity in CL6-xenografted nude mice as determined by inhibitory activity on tumor growth (58.41%) and lung metastasis (33.3%), as well as prolongation of survival time (62 days).

CONCLUSION

The K. galangal Linn. rhizome extract and its bioactive compound EPMC exhibited moderate cytotoxic activity against human CCA tumor (CL-6) cell line. Results of toxicity testing suggest that the extract was well tolerated up to the maximum single oral dose of 5000 mg/kg body weight and daily dose of 1000 mg/kg body weight for 30 days. The extract exhibited promising anti-CCA activity in CL6-xenografed nude mice as determined by significant inhibitory activity on tumor growth and lung metastasis, as well as prolongation of survival time.

Ethyl-p-methoxycinnamate isolated from Kaempferia galanga inhibits inflammation by suppressing interleukin-1, tumor necrosis factor-α, and angiogenesis by blocking endothelial functions

OBJECTIVE

The present study aimed to investigate the mechanisms underlying the anti-inflammatory and anti-angiogenic effects of ethyl-p-methoxycinnamate isolated from Kaempferia galanga.

METHODS

The anti-inflammatory effects of ethyl-p-methoxycinnamate were assessed using the cotton pellet granuloma assay in rats, whereby the levels of interleukin-1 and tumor necrosis factor-α were measured in the animals' blood. In addition, the levels of interleukin, tumor necrosis factor, and nitric oxide were measured in vitro using the human macrophage cell line (U937). The analgesic effects of ethyl-p-methoxycinnamate were assessed by the tail flick assay in rats. The anti-angiogenic effects were evaluated first by the rat aortic ring assay and, subsequently, by assessing the inhibitory effects of ethyl-p-methoxycinnamate on vascular endothelial growth factor, proliferation, migration, and tube formation in human umbilical vein endothelial cells.

RESULTS

Ethyl-p-methoxycinnamate strongly inhibited granuloma tissue formation in rats. It prolonged the tail flick time in rats by more than two-fold compared with the control animals. The inhibition of interleukin and tumor necrosis factor by ethyl-p-methoxycinnamate was significant in both in vivo and in vitro models; however, only a moderate inhibition of nitric oxide was observed in macrophages. Furthermore, ethyl-p-methoxycinnamate considerably inhibited microvessel sprouting from the rat aorta. These mechanistic studies showed that ethyl-p-methoxycinnamate strongly inhibited the differentiation and migration of endothelial cells, which was further confirmed by the reduced level of vascular endothelial growth factor.

CONCLUSION

Ethyl-p-methoxycinnamate exhibits significant anti-inflammatory potential by inhibiting pro-inflammatory cytokines and angiogenesis, thus inhibiting the main functions of endothelial cells. Thus, ethyl-p-methoxycinnamate could be a promising therapeutic agent for the treatment of inflammatory and angiogenesis-related diseases.

Antiangiogenic effects and mechanisms of trans-ethyl p-methoxycinnamate from Kaempferia galanga L

Kaempferia galanga L. (Zingiberaceae) is an aromatic herb and a popular spice used as a condiment in Asian cuisine. The ethanol extract of the dried plant and its successive four subfractions were investigated on zebrafish model by quantitative endogenous alkaline phosphatase assay. Both n-hexane and ethyl acetate fractions had antiangiogenic activity, and two major active components (trans-ethyl p-methoxycinnamate and kaempferol) showed potent antiangiogenic effects on wild-type zebrafish. Because of its much stronger effect and no antiangiogenic activity reported, trans-ethyl p-methoxycinnamate was further investigated for its action mechanism. It dose dependently inhibited vessel formation on both wild- and Tg(fli1a:EGFP)y1-type zebrafish embryos. The semiquantitative reverse transcription polymerase chain reaction assay suggested that trans-ethyl p-methoxycinnamate affects multiple molecular targets related to angiogenesis. In vitro, it specifically inhibited the migration and tube formation of human umbilical vein endothelial cells. In vivo, it could block bFGF-induced vessel formation on Matrigel plug assay.

Bioactivity-guided isolation of ethyl-p-methoxycinnamate, an anti-inflammatory constituent, from Kaempferia galanga L. extracts

This study evaluated the anti-inflammatory effect of Kaempferia galanga (KG) using an activity-guided approach. KG rhizomes were serially extracted with petroleum ether, chloroform, methanol and water. These extracts (2 g/kg each) were tested for their ability to inhibit carrageenan-induced rat paw edema. The chloroform extract was found to exert the highest inhibition (42.9%) compared to control (p < 0.001), hence it was further fractionated by washing serially with hexane, hexane-chloroform (1:1) and chloroform. The chloroform fraction (1 g/kg) showed the highest inhibitory effect (51.9%, p < 0.001) on carrageenan-induced edema. This chloroform fraction was further fractionated with hexane-chloroform (1:3) and chloroform, and of the two fractions, the hexane-chloroform sub-fraction was the most effective in inhibiting edema (53.7%, p < 0.001). GC-MS analysis of the active sub-fraction identified ethyl-p-methoxycinnamate (EPMC) as the major component, which was re-crystallized. EPMC dose-dependently inhibited carrageenan-induced edema with an MIC of 100 mg/kg. Moreover, in an in vitro study, EPMC non-selectively inhibited the activities of cyclooxygenases 1 and 2, with IC₅₀ values of 1.12 µM and 0.83 µM respectively. These results validate the anti-inflammatory activity of KG which may be exerted by the inhibition of cyclooxygenases 1 and 2. EPMC isolated from this plant may be the active anti-inflammatory agent.