Clerodendrum chinense Stem Extract and Nanoparticles: Effects on Proliferation, Colony Formation, Apoptosis Induction, Cell Cycle Arrest, and Mitochondrial Membrane Potential in Human Breast Adenocarcinoma Breast Cancer Cells.

Breast cancer stands out as the most widespread form of cancer globally. In this study, the anticancer activities of Clerodendrum chinense (C. chinense) stem ethanolic extract were investigated. High-performance liquid chromatography (HPLC) analysis identified verbascoside and isoverbascoside as the major bioactive compounds in the C. chinense stem extract. Successfully developed nanoparticles exhibited favorable hydrodynamic diameter, polydispersity index, and surface charge, thus ensuring stability after four months of storage. The total phenolic content and total flavonoid contents in the nanoparticles were reported as 88.62% and 95.26%, respectively. The C. chinense stem extract demonstrated a dose-dependent inhibitory effect on MCF-7, HeLa, A549, and SKOV-3 cancer cell lines, with IC50 values of 109.2, 155.6, 206.9, and 423 µg/mL, respectively. C. chinense extract and NPs exhibited dose-dependent cytotoxicity and the highest selectivity index values against MCF-7 cells. A dose-dependent reduction in the colony formation of MCF-7 cells was observed following treatment with the extract and nanoparticles. The extract induced cytotoxicity in MCF-7 cells through apoptosis and necrosis. C. chinense stem extract and nanoparticles decreased mitochondrial membrane potential (MMP) and induced G0/G1 phase arrest in MCF-7 cells. In conclusion, use of C. chinense stem extract and nanoparticles may serve as a potential therapeutic approach for breast cancer, thus warranting further exploration.

Phenylethanoid Glycoside-Enriched Extract Prepared from Clerodendrum chinense Leaf Inhibits A549 Lung Cancer Cell Migration and Apoptosis Induction through Enhancing ROS Production.

This study aims to investigate the antioxidant and anti-cancer activities of Clerodendrum chinense leaf ethanolic extract. The phenylethanoid glycoside-enriched extract, namely verbascoside and isoverbascoside, was determined in the ethanolic C. chinense leaf extract using the validated HPLC method. The ethanolic extract showed DPPH and ABTS free radical scavenging activities with the IC50 values of 334.2 ± 45.48 µg/mL and 1012.77 ± 61.86 µg/mL, respectively, and a FRAP value of 88.73 ± 4.59 to 2480.81 ± 0.00 µM. C. chinense leaf extract exhibited anti-proliferative activity against A549 lung cancer cells in a dose- and time-dependent manner, with the IC50 value of 340.63 ± 89.43, 210.60 ± 81.74, and 107.08 ± 28.90 µg/mL after treatment for 24, 48, and 72 h, respectively. The IC50 values of verbascoside, isoverbascoside, and hispidulin were 248.40 ± 15.82, 393.10 ± 15.27, and 3.86 ± 0.87 µg/mL, respectively, indicating that the anti-proliferative effects of the C. chinense leaf extract mainly resulted from hispidulin and verbascoside. The selectivity index (SI) of C. chinense leaf extract against A549 lung cancer cells vs. normal keratinocytes were 2.4 and 2.8 after incubation for 24 and 48 h, respectively, suggesting the cytotoxic selectivity of the extract toward the cancer cell line. Additionally, the C. chinense leaf extract at 250 µg/mL induced late apoptotic cells up to 21.67% with enhancing reactive oxygen species (ROS) induction. Furthermore, the lung cancer cell colony formation was significantly inhibited after being treated with C. chinense leaf extract in a dose-dependent manner. The C. chinense leaf extract at 250 µg/mL has also shown to significantly inhibit cancer cell migration compared with the untreated group. The obtained results provide evidence of the anti-lung cancer potentials of the C. chinense leaf ethanolic extract.

Electron Beam Irradiation Cross-Linked Hydrogel Patches Loaded with Red Onion Peel Extract for Transdermal Drug Delivery: Formulation, Characterization, Cytocompatibility, and Skin Permeation.

The use of bioactive molecules derived from medicinal plants in wound healing has recently attracted considerable attention in both research and public interest. In this work, we demonstrated the first attempt to incorporate the extract from Thai red onion skins in hydrogel patches intended for transdermal delivery. The red onion skin extract (ROSE) was first prepared and evaluated for cytotoxicity by MTT assay with both L929 and human dermal fibroblast cells. Hydrogel patches with porous microstructure and high water content were fabricated from polyvinyl alcohol (PVA) by electron beam irradiation and characterized for their physical, mechanical, morphological, and cytocompatible properties prior to the loading of ROSE. After decontamination by electron beam irradiation, the in vitro release profile exhibited the burst release of extract from ROSE-coated hydrogel patches within 5 h, followed by the sustained release up to 48 h. Finally, evaluation of skin permeation using Franz cell setup with a newborn pig skin model showed that the permeation of ROSE from the hydrogel patch increased with time and reached the maximum of 262 µg/cm2, which was well below the cytotoxicity threshold, at 24 h. These results demonstrated that our ROSE-coated hydrogel patches could potentially be used in transdermal delivery.

Ultraviolet Radiation Protective and Anti-Inflammatory Effects of Kaempferia galanga L. Rhizome Oil and Microemulsion: Formulation, Characterization, and Hydrogel Preparation.

Long-term UV radiation exposure can induce skin disorders such as cancer and photoallergic reactions. Natural products have been considered as non-irritate and potential sunscreen resources due to their UV absorption and anti-inflammatory activities. This study aimed to evaluate the in vitro ultraviolet radiation protective effect and anti-inflammatory activity of K. galanga rhizome oil and microemulsions. The chemical components of K. galanga rhizome oil was analyzed via gas chromatography coupled with mass spectrometry. Microemulsions containing K. galanga rhizome oil were formulated using a phase-titration method. The microemulsion was characterized for droplet size, polydispersity index, and zeta potential, using a dynamic light-scattering technique. The physical and chemical stability of the microemulsion were evaluated via a dynamic light scattering technique and UV-Vis spectrophotometry, respectively. The UV protection of K. galanga rhizome oil and its microemulsion were investigated using an ultraviolet transmittance analyzer. The protective effect of K. galanga rhizome oil against LPS-induced inflammation was investigated via MTT and nitric oxide inhibitory assays. In addition, a hydrogel containing K. galanga rhizome oil microemulsion was developed, stored for 90 days at 4, 30, and 45 °C, and characterized for viscosity, rheology, and pH. The chemical degradation of the main active compound in the microemulsion was analyzed via UV-Vis spectrophotometry. The formulated O/W microemulsion contained a high loading efficiency (101.24 ± 2.08%) of K. galanga rhizome oil, suggesting a successful delivery system of the oil. The size, polydispersity index, and zeta potential values of the microemulsion were optimized and found to be stable when stored at 4, 30, and 45 °C. K. galanga rhizome oil and microemulsion demonstrated moderate sun protective activity and reduced the nitric oxide production induced by LPS in macrophage cells, indicating that microemulsion containing K. galanga rhizome oil may help protect human skin from UV damage and inflammation. A hydrogel containing K. galanga rhizome oil microemulsion was developed as a topical preparation. The hydrogel showed good physical stability after heating and cooling cycles and long-term storage (3 months) at 4 °C. The use of K. galanga rhizome oil as a natural sun-protective substance may provide a protective effect against inflammation on the skin. K. galanga rhizome oil microemulsion was successfully incorporated into the hydrogel and has the potential to be used as a topical sunscreen preparation.

Development of Jelly Loaded with Nanogel Containing Natural L-Dopa from Mucuna pruriens Seed Extract for Neuroprotection in Parkinson's Disease.

The first line therapy of patients with Parkinson's disease, a neurodegenerative disorder caused by the degeneration of dopaminergic neurons, is levodopa (L-dopa) given orally. Recently, the presence of natural L-dopa in the seed of Mucuna pruriens, a tropical legume in the Fabaceae family, was reported and it showed superior efficiency compared with synthetic L-dopa. Therefore, this study aimed to examine the phytochemical compounds, particularly for natural L-dopa, in M. pruriens seed extract and subsequently prepare a nanogel containing the extract prior to incorporation into a jelly formulation for use as a functional food in elderly patients with Parkinson's disease. The results show that M. pruriens seed extract contains phenolic compounds, flavonoids, tannins, alkaloids, terpenoids, and saponins. The quantitative analysis performed by the HPLC method revealed that spray-dried M. pruriens seed extract contained 5.59 ± 0.21% L-dopa. M. pruriens seed extract possesses a ferric-reducing antioxidant power and shows free-radical scavenging activity, determined by DPPH and ABTS methods, suggesting a distinctive antioxidant ability of the extract. M. pruriens seed extract at 10 ng/mL did not show cytotoxicity against a neuronal cell line (SH-SY5Y cells), kidney cells (HEK293 cells), or Caco-2 cells. Nanogel of M. pruriens seed extract prepared by ionic gelation had the hydrodynamic diameter, polydispersity index and zeta potential value of 384.53 ± 11.24 nm, 0.38 ± 0.05, and -11.23 ± 1.15 mV, respectively. The transepithelial transport of L-dopa in M. pruriens seed-extract nanogel through Caco-2 cells was measured. Nanogel containing M. pruriens seed extract at the concentration of 10 ng/mL exhibited neuroprotective activity. A jelly formulation containing M. pruriens seed-extract nanogel was successfully developed. The prepared jelly exhibited the acceptable physical and microbiological stabilities upon 6 months of the stability test. The half-life of natural L-dopa in jelly were 3.2, 0.9, and 0.6 years for storage conditions at 4, 30, and 40 °C, respectively, indicating the thermal degradation of natural L-dopa. The prepared jelly containing natural L-dopa from M. pruriens seed extract with the prominent antioxidant activity is a promising option for elderly patients suffering from Parkinson's disease.

Phytochemical Analysis, Antioxidant, and Wound Healing Activity of Pluchea indica L. (Less) Branch Extract Nanoparticles.

Proliferation and migration of keratinocytes and fibroblasts play an important role in cutaneous wound healing, while oral mucosal squamous cell proliferation and migration are crucial for oral wound healing. In this study, the phytochemical profile of Pluchea indica branch ethanolic extract was characterized. The bioactive compound of Pluchea indica branch ethanolic extract was identified and analyzed by the validated HPLC method. The nanoparticles of P. indica branch extract were formulated by solvent displacement method to increase the solubility and the colloidal stability of the extract. The stability of the nanoparticles was investigated by using the dynamic light scattering technique. Effects of P. indica crude extract and nanoparticles on cell viability, proliferation and migration of primary epidermal keratinocytes, human dermal fibroblasts, and oral mucosal keratinocyte cells were investigated by MTT assay and scratch assay, respectively. The results showed that P. indica branch extract contained a high content of total phenolic and total flavonoids. The HPLC analysis revealed that the main compound in the extract was 4,5-O-dicaffeoylquinic acid. The cell viability of the extract and nanoparticles decreased when cells were exposed to a high concentration of extract and nanoparticles. These results demonstrate that P. indica branch extract and extract nanoparticles at specific concentrations possess in vitro wound healing activity and they may be possibly used to treat different types of wounds including dermal and oral mucosal wounds.

Anti-Austerity Activity of Thai Medicinal Plants: Chemical Constituents and Anti-Pancreatic Cancer Activities of Kaempferia parviflora.

Human pancreatic tumor cells have an intrinsic ability to tolerate nutrition starvation and survive in the hypovascular tumor microenvironment, the phenomenon termed as "austerity". Searching for an agent that inhibits such tolerance to nutrient starvation and kills the pancreatic cancer cells preferentially in nutrient-starvation is a unique anti-austerity strategy in anti-cancer drug discovery. In this strategy, plant extracts and compounds are tested against PANC-1 human pancreatic cancer cell line under the conditions of nutrient-deprived medium (NDM) and nutrient-rich medium (DMEM), to discover the compounds that show selective cytotoxicity in NDM. Screening of twenty-five Thai indigenous medicinal plant extracts for their anti-austerity activity against the PANC-1 human pancreatic cancer cell line in nutrient deprived medium (NDM) resulted in the identification of four active plants, Derris scandens, Boesenbergia pandurata, Citrus hystrix, and Kaempferia parviflora, with PC50 values 0.5-8.9 µg/mL. K. parviflora extract also inhibited PANC-1 cancer cell colony formation. Phytochemical investigation of K. parviflora extract led to the isolation of fourteen compounds, including two polyoxygenated cyclohexanes (1 and 2), eleven flavonoids (3-13), and ß-sitosterol (14). Stereochemical assignment of compound 1 was confirmed through X-ray analysis. All isolated compounds were tested for their preferential cytotoxicity against PANC-1 cells. Among them, 5-hydroxy-7-methoxyflavone (3) displayed the most potent activity with a PC50 value of 0.8 µM. Mechanistically, it was found to induce apoptosis in PANC-1 cell death in NDM as evident by caspase cleavage. It was also found to inhibit PANC-1 cancer cell colony formation in DMEM. Therefore, compound 3 can be considered as a potential lead compound for the anticancer drug development based on the anti-austerity strategy.

Wound healing activity of Pluchea indica leaf extract in oral mucosal cell line and oral spray formulation containing nanoparticles of the extract.

CONTEXT: Pluchea indica (L.) Less (Asteraceae) is an herb used as a traditional medicine for wound healing. The chemical compounds found in Pluchea indica leaves are phenolic acids, flavonoids, anthocyanins and carotenoids. OBJECTIVE: This study investigates the effect of Pluchea indica leaf ethanol extract and its nanoparticles (NPs) on cytotoxicity, cell survival and migration of human oral squamous carcinoma cell line. MATERIALS AND METHODS: Cell viability was measured using MTT assay to assess the effect of Pluchea indica leaf extract and NPs (1-500 µg/mL) on cytotoxicity and cell survival. The effect of Pluchea indica leaf extract and NPs on cell migration was determined by scratch assay. The % relative migration was calculated after 24, 48 and 72 h of treatment. RESULTS: The sizes of Pluchea indica leaf extract NPs were in a range of nanometers. NPs possessed negative charge with the polydispersity index (PDI) smaller than 0.3. After the treatment for 24, 48 and 72 h, Pluchea indica leaf extract had IC50 value of 443.2, 350.9 and 580.5 µg/mL, respectively, whereas the IC50 value of NPs after the treatment for 24, 48 and 72 h were 177.4, 149.2 and 185.1 µg/mL, respectively. The % relative migration of cells was significantly increased when the cells were treated with 62.5 and 125 µg/mL of the extract and 62.5 µg/mL of NPs. DISCUSSION AND CONCLUSIONS: NPs increased cytotoxicity of the Pluchea indica leaf extract, increased the migration of cells at low concentration and increased colloidal stability of the extract in an oral spray formulation.

Highly oxygenated antiausterity agents from the leaves of Uvaria dac.

From the chloroform extract of the leaves of Uvaria dac, four new highly-oxygenated cyclohexene derivatives named uvaridacols I-L (1-4) were isolated together with nine previously reported compounds (5-13). Their structures were determined based on the extensive NMR spectroscopic data and circular dichroism spectroscopic analysis. Among the new compounds, uvaridacol L (4) displayed strong preferential cytotoxicity in the nutrient deprived medium against five different tested pancreatic cancer cell lines, PANC-1 (PC50, 20.1µM), PSN-1 (PC50, 9.7µM), MIA PaCa-2 (PC50, 29.1µM), Capan-1 (73.0µM) and KLM-1 (25.9µM).

Chrysin Inhibits Lymphangiogenesis in Vitro.

The induction of lymphangiogenesis is an important process to promote cancer growth and cancer metastasis via the lymphatic system. Identifying the compounds that can prevent lymphangiogenesis for cancer therapy is urgently required. Chrysin, 5,7-dihydroxyflavone, a natural flavone extracted from Thai propolis, was used to investigate the effect on the lymphangiogenesis process of TR-LE, rat lymphatic endothelial cells. In this study, maximal nontoxic doses of chrysin on TR-LE cells were selected by performing a proliferation assay. The process of lymphangiogenesis in vitro was determined by cord formation assay, adhesion assay and migration assay. Chrysin at a nontoxic dose (25 µM) significantly inhibited cord formation, cell adhesion and migration of TR-LE cells when compared with the control group. We also found that chrysin significantly induced vascular endothelial growth factor C (VEGF-C) mRNA expression and nitric oxide (NO) production in TR-LE cells which was involved in decreasing the cord formation of TR-LE cells. In conclusion, we report for the first time that chrysin inhibited the process of lymphangiogenesis in an in vitro model. This finding may prove to be a natural compound for anti-lymphangiogenesis that could be developed for use in cancer therapy.

Chemical Composition of the Essential Oil from Croton oblongifolius and its Antibacterial Activity against Propionibacterium acnes.

The essential oil of C. oblongifolius Roxb. stem bark was obtained by hydrodistillation. Chemical analysis by GC-MS identified 29 compounds. Terpinen-4-ol (17.8%) was a major component, together with α-guaiene (7.9%), E-caryophyllene (7.0%), myrcene (6.7%), (+)-cyclosativene (5.1%), sabinene (4.8%), aciphyllene (4.7%), pogostol (4.6%), gamma-terpinene (3.4%), α-muurolol (3.2%) and germecrene D (3.2%). The essential oil exhibited antibacterial activity against Propionibacterium acnes ATCC 6919 with an MIC of 0.125%, v/v.

(+)-Grandifloracin, an antiausterity agent, induces autophagic PANC-1 pancreatic cancer cell death.

Human pancreatic tumors are known to be highly resistant to nutrient starvation, and this prolongs their survival in the hypovascular (austere) tumor microenvironment. Agents that retard this tolerance to nutrient starvation represent a novel antiausterity strategy in anticancer drug discovery. (+)-Grandifloracin (GF), isolated from Uvaria dac, has shown preferential toxicity to PANC-1 human pancreatic cancer cells under nutrient starvation, with a PC50 value of 14.5 µM. However, the underlying mechanism is not clear. In this study, GF was found to preferentially induce PANC-1 cell death in a nutrient-deprived medium via hyperactivation of autophagy, as evidenced by a dramatic upregulation of microtubule-associated protein 1 light chain 3. No change was observed in expression of the caspase-3 and Bcl-2 apoptosis marker proteins. GF was also found to strongly inhibit the activation of Akt, a key regulator of cancer cell survival and proliferation. Because pancreatic tumors are highly resistant to current therapies that induce apoptosis, the alternative cell death mechanism exhibited by GF provides a novel therapeutic insight into antiausterity drug candidates.

A flavonoid chrysin suppresses hypoxic survival and metastatic growth of mouse breast cancer cells.

Tumor hypoxia commonly occurs in solid tumors, and correlates with metastasis. Current cancer therapies are inefficient in curing metastatic disease. Herein, we examined effect of Thai propolis extract and its major constituent, chrysin, on hypoxic survival of 4T1 mouse breast cancer cells in vitro, and investigated its underlying mechanism. In vivo effect of chrysin on metastatic progression of cancer cells was studied, both as a single agent and in combination with another antimetastatic agent, agonistic monoclonal antibody targeting the DR5 TRAIL receptor (DR5 mAb). Thai propolis extract and chrysin decreased survival of 4T1 cells after exposure to hypoxia (1% O2), for 2 days. Immunoblot analysis revealed that chrysin inhibited hypoxia-induced STAT3 phosphorylation without affecting HIF-1α protein level. Chrysin also abrogated hypoxia-induced VEGF gene expression as determined by qRT-PCR. The in vivo effect of chrysin was determined in a spontaneous metastasis mouse model of breast cancer, either alone or in combination with DR5 mAb. Daily oral administration of chrysin in Balb/c mice implanted with 4T1 cells significantly suppressed growth of lung metastatic colonies. Moreover, antimetastatic activity of DR5 mAb was enhanced when given in combination with chrysin. We demonstrate that chrysin has potential in controlling metastatic progression.

Chrysin overcomes TRAIL resistance of cancer cells through Mcl-1 downregulation by inhibiting STAT3 phosphorylation.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively kills various types of cancer cells without harming normal cells, but TRAIL resistance has been frequently observed in cancer cells. Propolis (bee glue) is a material collected from various plants by honeybees and is a rich source of bioactive compounds, including the natural flavonoid chrysin, which possesses multiple anticancer effects. We investigated the mechanism underlying the TRAIL sensitization effect of chrysin, which is a major constituent of Thai propolis, in human lung and cervical cancer cell lines. Propolis extract and chrysin sensitizes A549 and HeLa human cancer cell lines to TRAIL-induced apoptosis. The TRAIL sensitization effect of chrysin is not mediated by inhibition of TRAIL-induced NF-κB activation or by glutathione depletion. Immunoblot analysis using a panel of anti-apoptotic proteins revealed that chrysin selectively decreases the levels of Mcl-1 protein, by downregulating Mcl-1 gene expression as determined by qRT-PCR. The contribution of Mcl-1 in TRAIL resistance was confirmed by si-Mcl-1 knockdown. Among signaling pathways that regulate Mcl-1 gene expression, only constitutive STAT3 phosphorylation was suppressed by chrysin. The proposed action of chrysin in TRAIL sensitization by inhibiting STAT3 and downregulating Mcl-1 was supported by using a STAT3­specific inhibitor, cucurbitacin-I, which decreased Mcl-1 levels and enhanced TRAIL-induced cell death, similar to that observed with chrysin treatment. In conclusion, we show the potential of chrysin in overcoming TRAIL resistance of cancer cells and elucidate its mechanism of action.

Chemical constituents of Thai propolis.

Phytochemical investigation on the constituents of Thai propolis led the isolation of a new phenylallylflavanone, (7″S)-8-[1-(4'-hydroxy-3'-methoxyphenyl)prop-2-en-1-yl]-(2S)-pinocembrin (1) and (E)-cinnamyl-(E)-cinnamylidenate (2) from methanolic extract of Thai propolis. Their structures were determined on the basis of extensive NMR spectroscopic analysis. In addition to this, 19 compounds (3-21) belonging to flavonoids and phenolic esters were isolated and identified.

Uvaridacols E-H, highly oxygenated antiausterity agents from Uvaria dac.

Chemical investigation of the stems of Uvaria dac yielded four new highly oxygenated cyclohexene derivatives named uvaridacols E-H (1-4). Their structures were established through NMR and circular dichroism spectroscopic analysis. Uvaridacols E (1), F (2), and H (4) displayed weak preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions in a concentration-dependent manner, without causing toxicity in normal nutrient-rich conditions.

Antiausterity agents from Uvaria dac and their preferential cytotoxic activity against human pancreatic cancer cell lines in a nutrient-deprived condition.

Human pancreatic cancer cell lines are known for their inherent tolerance to nutrition starvation, which enables them to survive under a hypovascular (austerity) tumor microenvironment. The search for agents that preferentially retard the survival of cancer cells under low nutrition conditions (antiausterity agent) is a novel approach to anticancer drug discovery. In this study, it was found that a dichloromethane extract of the stem of Uvaria dac preferentially inhibited PANC-1 human pancreatic cancer cells survival under nutrition-deprived conditions at a concentration of 10 µg/mL. Workup of this bioactive extract led to the discovery of (+)-grandifloracin (8) as a potent antiausterity agent as evaluated in a panel of four human pancreatic cancer cell lines, PANC-1 (PC(50), 14.5 µM), PSN-1 (PC(50), 32.6 µM), MIA PaCa-2 (PC(50), 17.5 µM), and KLM-1 (32.7 µM). (+)-Grandifloracin (8) has been isolated from a natural source for the first time. Its absolute stereochemistry was established by single-crystal X-ray crystallography and circular dichroism spectroscopic analysis. In addition to this, seven other new highly oxygenated cyclohexene derivatives, named uvaridacanes A (1) and B (2), uvaridacols A-D (3, 4, 6, 7), and uvaridapoxide A (5), were also isolated and structurally characterized.

COX-1, COX-2 inhibitors and antifungal agents from Croton hutchinsonianus.

Two new compounds, 3'-(4''-hydroxy-3'',5''-dimethoxyphenyl)-propyl benzoate (1) and 3'-(4''-hydroxyphenyl)-propyl benzoate (3) together with known compounds, 3'-(4''-hydroxy-3''-methoxyphenyl)-propyl benzoate (2), poilaneic acid (4), farnesyl acetone (5) and 4-hydroxybenzaldehyde (6) were isolated and identified from the branches of Croton hutchinsonianus. Their structures were determined by spectroscopic methods. The three phenylpropyl benzoates (1-3) were found to exhibit antifungal activity against Candida albicans (IC(50) 5.36-11.41 microg/ml). Compounds 1-2 (IC(50) 2.11-4.95 microg/ml) exhibited potent but non-selective activity against the enzymes cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) whereas 3 (IC(50) 1.88 microg/ml) preferentially inhibited the enzyme COX-2.