Anti-Acanthamoeba activity of a semi-synthetic mangostin derivative and its ability in removal of Acanthamoeba triangularis WU19001 on contact lens

Garcinia mangostana L., also known as the mangosteen tree, is a native medicinal plant in Southeast Asia having a wide variety of pharmacologically active compounds, including xanthonoid mangostin. In this study, we examined the pharmacological activities of the selected semi-synthetic mangostin derivative, namely, amoebicidal activity, encystation inhibition, excystation activity, and removal capacity of adhesive Acanthamoeba from the surface of contact lens (CL). Among the three derivatives, C1 exhibited promising anti-Acanthamoeba activity against Acanthamoeba triangularis WU19001 trophozoites and cysts. SEM images displayed morphological changes in Acanthamoeba trophozoites, including the loss of acanthopodia, pore formation in the cell membrane, and membrane damage. In addition, the treated cyst was shrunken and adopted an irregular flat cyst shape. Under a fluorescence microscope, acridine orange and propidium iodide (AO/PI) staining revealed C1 induced condensation of cytoplasm and chromatin with the loss of cell volume in the treated trophozoites, while calcofluor white staining demonstrated the leakage of cell wall in treated cysts, leading to cell death. Interestingly, at the concentration ranges in which C1 showed the anti-Acanthamoeba effects (IC₅₀ values ranging from 0.035-0.056 mg/mL), they were not toxic to Vero cells. C1 displayed the highest inhibitory effect on A. triangularis encystation at 1/16×MIC value (0.004 mg/mL). While C1 demonstrated the excystation activity at 1/128×MIC value with a high rate of 89.47%. Furthermore, C1 exhibited the removal capacity of adhesive Acanthamoeba from the surface of CL comparable with commercial multipurpose solutions (MPSs). Based on the results obtained, C1 may be a promising lead agent to develop a therapeutic for the treatment of Acanthamoeba infections and disinfectant solutions for CL.

Oral Administration of Garcinia dulcis Flower Extract Lowers Arterial Blood Pressure of 2-kidneys-1-clip Renovascular Hypertensive Rat

The hexane insoluble fraction of the Garcinia dulcis (GD) flower extract comprises mainly camboginol and morelloflavone which possess potent in vivo and in vitro antioxidant properties. This study aimed to evaluate the effects of 4-week oral administration of GD flower extract on the arterial blood pressure (ABP) and the excretory function of the kidney in the 2-kidneys-1-clip (2K1C) renovascular hypertensive rats (total=12) compared to sham operated (SO) normotensive Wistar rats (total=12). Four weeks after hypertensive-induced surgery, either 50 mg/kg BW GD flower extract or vehicle was orally administered to the 2K1C or SO groups (n=6/group) daily for four weeks. ABP and the renal excretory function were studied in anesthetized rats, and expression of endothelial nitric oxide synthase (eNOS) mRNA in the isolated thoracic aorta were measured. In the 2K1C rats, GD flower extract significantly decreased ABP while increased significantly eNOS mRNA levels. GD flower extract did not exert a diuretic effect in either SO and 2K1C rats since there was no change in observed urine excretion, but it did tend to attenuated the renal tubular damage caused by renovascular hypertension. GD flower extract was anti-hypertensive in this model of renovascular hypertension and problably acts via the endothelial nitric oxide signaling pathway.

Effects of Artonin E on Cell Growth Inhibition and Apoptosis Induction in Colon Cancer LoVo and HCT116 Cells

Today, colon cancer is the leading cause of cancer death. In Thailand, colon cancer is the third most common cancer in men and the second in women. Currently, the treatments for colon cancer include surgery, chemotherapy, radiation therapy, immunotherapy, hormone therapy, targeted drug therapy, and stem cell therapy. However, some treatments have side effects for cancer patients, causing unwanted symptoms. In addition, targeted therapy comes with a high cost for patients. Therefore, bioactive compounds might be a good choice for colon cancer treatment. In this study, we investigated the effect of artonin E on apoptosis induction in colon cancer LoVo and HCT116 cells. The concentration ranges of artonin E at 3, 5, 10, and 30 µg/mL in LoVo cells and 1, 1.5, 2, and 3 µg/mL in HCT116 cells were examined. The results implied that artonin E decreased cell viability and increased apoptotic cells in a dose-dependent manner. In addition, artonin E stimulated mitochondrial membrane potential (ΔΨm) changes associated with apoptosis by increasing the sub-G1 population analyzed by flow cytometry. Western blotting showed that artonin E increased the proapoptotic protein, Bax, and decreased anti-apoptotic proteins’ (Bcl-2 and Bcl-x) expression. Moreover, artonin E also increased cleaved caspase-7 and cleaved-PARP expression in both LoVo and HCT116 cells. Interestingly, artonin E induced apoptosis through p-ERK1/2, p-p38/p38, and p-c-Jun expression in both cells. Our results suggested that artonin E induced apoptosis via caspase activation associated with the MAPKs signaling pathway. Therefore, artonin E might be used as a potential anticancer drug for colon cancer in the future.

Phytochemical, anti-Acanthamoeba, and anti-adhesion properties of Garcinia mangostana flower as preventive contact lens solution

Acanthamoeba keratitis infection extends due to the growing number of contact lens users. Indigenous plants including Garcinia mangostana play a vital role in human health and well being. Many species of this plant have been reported with myriads of potent medicinal properties. However, the aims of this study were, for the first time, to isolate compounds from the flower of G. mangostana and to test their anti-Acanthamoeba and anti-adhesion activity against Acanthamoeba triangularis. Powdered flowers of G. mangostana were extracted and chromatographed on a silica gel column. The structures of the compounds were established with the aid of ¹H NMR. More so, the anti-Acanthamoeba and anti-adhesion properties were tested on a 96-well polystyrene microtiter plate and soft contact lenses. Scanning electron microscope (SEM) was used to determine the features of A. triangularis on contact lenses. Eight pure compounds were obtained, namely 9-hydroxycalabaxanthone, tovophillin A, garcinone E, garcinone B, α-mangostin, gartinin, 8-deoxygartinin and γ-mangostin. The extract and pure compounds exhibited anti-Acanthamoeba activity with MIC values in the range of 0.25-1 mg/mL. In addition, the extract and α-mangostin displayed significant activity against the adhesion of A. triangularis trophozoites both in polystyrene plate and in contact lenses at 0.5 × MIC (0.25 mg/mL). Furthermore, α-mangostin has the potential to remove A. triangularis adhesion in contact lenses similar to a commercial multipurpose solution (MPS). SEM study confirmed that crude extract and α-mangostin are effective as solutions for contact lenses, which removed A. triangularis trophozoites within 24 h. Alpha-mangostin was non-toxic to Vero cells at a concentration below 39 μM in 24 h. Crude extract of G. mangostana flower and its α-mangostin serve as candidate compounds in the treatment of Acanthamoeba infection or as lens care solution, since they can be used as a source of natural products against Acanthamoeba and virulence factor associated with the adhesion of A. triangularis.

Anti-Acanthamoeba synergistic effect of chlorhexidine and Garcinia mangostana extract or α-mangostin against Acanthamoeba triangularis trophozoite and cyst forms

Acanthamoeba spp. can cause amoebic keratitis (AK). Chlorhexidine is effective for AK treatment as monotherapy, but with a relative failure on drug bioavailability in the deep corneal stroma. The combination of chlorhexidine and propamidine isethionate is recommended in the current AK treatment. However, the effectiveness of treatment depends on the parasite and virulence strains. This study aims to determine the potential of Garcinia mangostana pericarp extract and α-mangostin against Acanthamoeba triangularis, as well as the combination with chlorhexidine in the treatment of Acanthamoeba infection. The minimal inhibitory concentrations (MICs) of the extract and α-mangostin were assessed in trophozoites with 0.25 and 0.5 mg/mL, for cysts with 4 and 1 mg/mL, respectively. The MIC of the extract and α-mangostin inhibited the growth of A. triangularis trophozoites and cysts for up to 72 h. The extract and α-mangostin combined with chlorhexidine demonstrated good synergism, resulting in a reduction of 1/4–1/16 of the MIC. The SEM results showed that Acanthamoeba cells treated with a single drug and its combination caused damage to the cell membrane and irregular cell shapes. A good combination displayed by the extract or α-mangostin and chlorhexidine, described for the first time. Therefore, this approach is promising as an alternative method for the management of Acanthamoeba infection in the future.

Tedaniophorbasins A and B-Novel Fluorescent Pteridine Alkaloids Incorporating a Thiomorpholine from the Sponge Tedaniophorbas ceratosis

Two new fluorescent pteridine alkaloids, tedaniophorbasins A (1) and B (2), together with the known alkaloid N-methyltryptamine, were isolated, through application of mass directed purification, from the sponge Tedaniophorbas ceratosis collected from northern New South Wales, Australia. The structures of tedaniophorbasins A and B were deduced from the analysis of 1D/2D NMR and MS data and through application of ¹³C NMR DFT calculations. Tedaniophorbasin A possesses a novel 2-imino-1,3-dimethyl-2,3,7,8-tetrahydro-1H-[1,4]thiazino[3,2-g]pteridin-4(6H)-one skeleton, while tedaniophorbasin B is its 2-oxo derivative. The compounds show significant Stokes shifts (~14,000 cm⁻¹) between excitation and emission wavelengths in their fluorescence spectra. The new compounds were tested for bioactivity against chloroquine-sensitive and chloroquine-resistant strains of the malaria parasite Plasmodium falciparum, breast and pancreatic cancer cell lines, and the protozoan parasite Trypanosoma brucei brucei but were inactive against all targets at 40 µM.

New flavonoids and xanthone from the stem bark of Artocarpus rigidus blume and cytotoxicity

Three new flavonoids named artorigidinones A-C and a new xanthone named artorixanthone together with seven known compounds were isolated from the stem bark of Artocarpus rigidus Blume. Their structures were characterized by spectroscopic data. γ-Geranylapigenin exhibited cytotoxicity to a fibroblast-like cell line (SW1353) (IC₅₀ < 0.32 µg/mL) stronger than a standard drug.

Artonin E sensitizes TRAIL-induced apoptosis by DR5 upregulation and cFLIP downregulation in TRAIL-refractory colorectal cancer LoVo cells

Background

The TRAIL treatment is an ideal strategy for colorectal cancer (CRC) therapy because of minimal collateral damage to normal cells. Unfortunately, some CRC is TRAIL-refractory cancer, such as LoVo cells. In an effort to overcome TRAIL-refractory cancer, we investigated the effect of artonin E in regulating death receptor 5 (DR5) and cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (cFLIP), two major mediators regulate TRAIL-induced apoptosis, in LoVo cells as a model of TRAIL refractory CRC.

Methods

TRAIL-refractory cancer (LoVo cells) was treated with artonin E and TRAIL. Cell viability was determined by MTT assay. Apoptotic chromatin condensation was observed by fluorescent Hoechst33342 staining. The mRNA and protein expression of DR5 and FLIP was determined by quantitative PCR and Western blotting analysis, respectively.

Results

The combination treatment of artonin E and TRAIL enhanced cytotoxicity and apoptotic chromatin condensation in LoVo cells significantly, while treatment of artonin E or TRAIL alone was not. Artonin E enhanced both mRNA and protein expression of DR5. Interestingly, this is the first report showing that artonin E decreased protein expression of cFLIP. All together we showed that artonin E enhanced TRAIL-induced apoptosis in LoVo cells through DR5 upregulation and cFLIP downregulation.

Conclusions

Artonin E was able to increase DR5 expression and decrease cFLIP expression in LoVo cells. These results showed that LoVo cells sensitized TRAIL-induced apoptosis in combined treatment with artonin E and TRAIL. Therefore, the combination treatment of artonin E and TRAIL is one of the potential strategies used for TRAIL-refractory CRC therapy in the future.

Goniothalamin induces mitochondria-mediated apoptosis associated with endoplasmic reticulum stress-induced activation of JNK in HeLa cells

Goniothalamin, a natural occurring styryl-lactone isolated from Goniothalamus macrophyllus (Blume) Hook. f. & Thomson var. macrophyllus, can trigger cancer cell death in various types of cancer cell. The present study focused on elucidation of the mitochondria-mediated apoptosis associated with endoplasmic reticulum (ER) stress-induced activation of c-Jun NH₂-terminal kinase (JNK) by goniothalamin in HeLa cervical cancer cells. Cell viability was determined using an MTT assay, and DNA condensation and loss of mitochondrial membrane potential were determined using Hoechst 33342 and JC-1 staining, respectively. Flow cytometry was used for cell cycle and phosphatidyl-serine exposure analyses. Apoptotic-associated ER stress signaling pathways were determined using immunoblotting, reverse transcription-polymerase chain reaction (RT-PCR) and RT-quantitative PCR analyses. The results suggested that goniothalamin suppressed cell proliferation in a time- and dose-dependent manner. The induction of apoptosis was confirmed by increased DNA condensation, loss of mitochondrial membrane potential and cell surface phosphatidyl-serine presentation. The cell cycle analysis demonstrated that the goniothalamin-treated HeLa cells were in G2/M arrest. Determination of the caspase cascade and apoptotic proteins indicated the induction of apoptosis through the intrinsic pathway. In addition, the levels of phosphorylated JNK and the transcription factor, C/EBP homologous protein (CHOP), an ER stress-associated apoptotic molecule, were increased in the goniothalamin-treated cells. These data indicated that goniothalamin exerted a cytotoxic effect against HeLa cells via the induction of mitochondria-mediated apoptosis, associated with ER stress-induced activation of JNK.

Anti-Proliferation and Apoptosis Induction in Breast Cancer Cells by Cratoxylum cochinchinense Extract

BACKGROUND

Breast cancer is the most common invasive cancer in females worldwide. It was found about 37.5% in Thai females and is one of the leading causes of death-related cancers in women. Therefore, new finding of anti-cancer compound as a therapeutic candidate in breast cancer is necessary.

OBJECTIVE

To investigate the effect of Cratoxylum cochinchinense extract on anti-proliferation and apoptosis induction in breast cancer cells.

MATERIAL AND METHOD

Cell proliferation and cell viability assay were determined by MTT assay. Hoechst 33342 and JC-1 staining were used to determined nuclear morphological changes and mitochondrial membrane potential, respectively.

RESU;TS

C. cochinchinense extract showed anti-proliferation in MDA-MB-468 treated cells in a time- and dose-dependent manner with IC50 value of 19.19+0.8 μg/ml. In addition, C. cochinchinense extract induced nuclear condensation and apoptotic bodies in MDA-MB-468 treated cells. JC-1 staining revealed that C. cochinchinense extract induced mitochondrial membrane dysfunction.

CONCLUSION

C. cochinchinense extract showed anti-proliferation and apoptosis induction properties in MDA-MB-468 treated cells. These results suggested that C. cochinchinense extract may be a potential candidate for anti-cancer drug developing. The underlying mechanisms of apoptosis induction should be further studied.

Constituents of Fagraea fragrans with Antimycobacterial Activity in Combination with Erythromycin

Seven new compounds constituted by three secoiridoids (1-3), two isocoumarins (4 and 5), an iridoid (6), and an aromatic derivative (7) in addition to 24 known compounds were isolated from the stem bark of Fagraea fragrans. The structures of the new compounds were determined on the basis of spectroscopic data analysis. The isolated compounds showed no antibacterial activity against Staphylococcus aureus and Escherichia coli. However, 5-formylisochromen-1-one (4), (-)-mellein (8), and swermacrolactone C (9) exhibited potent antimycobacterial activities against Mycobacterium smegmatis when used in combination with the antibiotic drug erythromycin.

Antiproliferation and Apoptosis Induction in Colorectal Cancer Cells by Goniothalamin

OBJECTIVE

To investigate the effect of goniothalamin on antiproliferation and apoptosis induction in three types of colorectal cancer cells.

BACKGROUND

Colorectal cancer is the third of the twentieth most commonly diagnosed cancer. Different types of colorectal cancer cells differ in genotype and characteristics leading to different responses to anticancer drugs. Therefore, finding new anticancer compound for the colorectal cancer cells is necessary.

MATERIAL AND METHOD

Antiproliferative response of goniothalamin on three colorectal cancer cell lines including Colo 205, SW480, and LoVo were determined by MTT assay. The antiproliferative response at different time and dose was also observed. Apoptosis induction by goniothalamin was observed in all three cell-lines via morphological changes and nuclear condensation by Hoechst33342 staining.

RESULTS

Goniothalamin showed different antiproliferative response on Colo 205, SW480, and Lo Vo cells at the IC50 value is 9.86 ± 0.38 µM, 22.00 ± 4.40 µM, and 65.25 ± 1.85 µM respectively. In addition, the antiproliferative response of goniothalamin was a time- and dose-dependent manner Apoptosis morphological changes and nuclear condensation were clearly observed in Colo 205, SW480 and LoVo cells treated with 10 µM, 25 µM, and 50 µM goniothalamin, respectively.

CONCLUSION

Goniothalamin showed antiproliferation and apoptosis induction in colorectal cancer cells with different sensitivity depending on cell type. Investigation of mechanisms underlying apoptosis and its potential use for colorectal cancer treatment should be further studied.

Emilia sonchifolia extract activity against white spot syndrome virus and yellow head virus in shrimp cell cultures

Emilia sonchifolia (L.) DC is a plant used in traditional medicine to treat several viral and bacterial diseases. The antiviral activities of selected Sephadex LH-20 column fractions and HPLC subfractions of an acetone extract of E. sonchifolia leaves were determined in shrimp Penaeus merguiensis primary lymphoid cells infected with either white spot syndrome virus (WSSV) or yellow head virus (YHV). WSSV and YHV replication was quantified using quantitative real-time PCR tests targeted to the VP19 and ORF1b gene transcripts, respectively. In lymphoid organ cells exposed to 100 µg ml⁻¹ of either the Sephadex fraction F14 or the HPLC F14 subfraction SF4, both fractions caused reduced replication, but YHV replication was reduced only by SF4. In the asthiazolyl blue mitochondrial enzyme activity assays to assess extract cytotoxicity, >60% of primary lymphoid organ cells remained viable following exposure to 100 µg ml⁻¹ of either F14 or SF4. GC-MS analysis of the HPLC F14 subfraction SF4 showed that it contained 2,4-di-tert-butylphenol. This study is the first to show that E. sonchifolia leaf extracts might be useful as bioactive agents to protect shrimp against viruses such as WSSV and YHV.

A new anthraquinone from Morinda elliptica Ridl

A new anthraquinone, morinquinone, together with 18 known anthraquinones were isolated from the stems of Morinda elliptica Ridl. Their structures were elucidated on the basis of spectroscopic data. They each showed weak inhibitory activity against a susceptible strain of Staphylococcus aureus and a methicillin-resistant S. aureus. Damnacanthal was effective against Microsporum gypseum (MIC 1 μg/mL). Lucidin was active against Entamoeba histolytica (MIC 31.25 μg/mL) and Giardia intestinalis (MIC 7.8 μg/mL).

New acridone from the wood of Citrus reticulata Blanco

A new acridone, named citruscridone (1) together with five known compounds were isolated from the wood of Citrus reticulata Blanco. Their structures were established based on spectroscopic evidence. The antibacterial and antifungal activities of the wood extracts and pure compounds were evaluated.

Alkaloid and coumarins from the green fruits of Aegle marmelos

Five (1-5) and 15 known compounds were isolated from the acetone extract of the green fruits of Aegle marmelos. The structure of compounds 1-5, marmesiline (1), 6-(4-acetoxy-3-methyl-2-butenyl)-7-hydroxycoumarin (2), 6-(2-hydroxy-3-hydroxymethyl-3-butenyl)-7-hydroxycoumarin (3), marmelonine (4) and 8-hydroxysmyrindiol (5), were determined on the basis of spectroscopic analyses. Antifungal and antibacterial activities of selected compounds were also evaluated.

Morelloflavone, a biflavonoid inhibitor of migration-related kinases, ameliorates atherosclerosis in mice

While macrophages take up modified LDL to form foam cells and multiply to develop fatty streaks, vascular smooth muscle cells (VSMC) migrate from the media to intima, secrete extracellular matrix, and increase the volume of atherosclerotic lesions. A medicinal plant Garcinia dulcis has been used in traditional Thai medicine for centuries to treat various chronic human diseases. Morelloflavone, a biflavonoid and an active ingredient of the plant, has been shown to inhibit VSMC migration through its inhibition of multiple migration-related kinases such as focal adhesion kinase, c-Src, ERK, and RhoA. However, the exact role of morelloflavone in atherosclerogenesis was unknown. We fed Ldlr(-/-)Apobec1(-/-) mice with either normal chow or chow containing 0.003% morelloflavone for 8 mo and assessed the extent of atherosclerosis by the en face and cross-sectional analyses. A cell composition analysis of atherosclerotic tissue was carried out using immunohistochemical staining. Oral morelloflavone therapy significantly reduced the atherosclerotic areas of the mouse aortas (a 26% reduction), without changing plasma lipid profiles or weights. Immunohistochemical analyses showed that morelloflavone reduced the number of VSMC in the atherosclerotic lesion while it did not change the density of macrophages in the lesion or the percentages of proliferating and apoptotic cells. Oral, low-dose, morelloflavone therapy retards atherosclerogenesis by limiting the migration of VSMC into the intima in the mouse model of human atherosclerosis. Upon further investigation, morelloflavone may be found to be a novel oral antiatherosclerotic agent and a viable addition to the conventional therapies such as statins in humans.

Morelloflavone from Garcinia dulcis as a novel biflavonoid inhibitor of HMG-CoA reductase

Morelloflavone, a biflavonoid from Garcinia dulcis previously shown to have hypocholesterolemic activity, was examined for its effect on HMG-CoA reductase, the rate-limiting enzyme of the cholesterol biosynthetic pathway. By using the catalytic domain of house mouse HMG-CoA reductase, morelloflavone was found to inhibit the enzyme activity by competing with HMG-CoA whereas it was non-competitive towards NADPH. The inhibition constants (K(i)) with respect to HMG-CoA and NADPH were 80.87 ± 0.06 µm and 103 ± 0.07 µm, respectively. Both flavonoid subunits of this compound, naringenin and luteolin, equally competed with HMG-CoA with K(i) of 83.58 ± 4.37 µm and 83.59 ± 0.94 µm, respectively, and were also non-competitive with NADPH (K(i) of 182 ± 0.67 µm and 188 ± 0.14 µm, respectively). Due to these findings, we suggest that each subunit of morelloflavone would occupy the active site of the enzyme, thereby blocking access of its substrate. The present study thus demonstrates the ability of morelloflavone from G. dulcis to inhibit HMG-CoA reductase in vitro. As a result, this biflavonoid might serve as a new candidate for the future development of hypocholesterolemic agents.

Naphthoquinones, anthraquinones and naphthalene derivatives from the bulbs of Eleutherine americana

A new naphthoquinone, named eleuthinone A ( 8), two new anthraquinones, named eleuthraquinone A and B ( 12, 13), a naphthalene derivative, named eleucanarol ( 14) were isolated from the bulbs of ELEUTHERINE AMERICANA, together with two new natural products previously synthesized, and nine known compounds. Their structures were established based on spectroscopic evidence. Their antibacterial activities against STAPHYLOCOCCUS AUREUS ATCC25923 and ATCC27664, an enterotoxin producing strain were investigated.

Rhodomyrtone: a new candidate as natural antibacterial drug from Rhodomyrtus tomentosa

Rhodomyrtone [6,8-dihydroxy-2,2,4,4-tetramethyl-7-(3-methyl-1-oxobutyl)-9-(2-methylpropyl)-4,9-dihydro-1H-xanthene-1,3(2H)-di-one] from Rhodomyrtus tomentosa (Aiton) Hassk. displayed significant antibacterial activities against gram-positive bacteria including Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Staphylococcus epidermidis, Streptococcus gordonii, Streptococcus mutans, Streptococcus pneumoniae, Streptococcus pyogenes, and Streptococcus salivarius. Especially noteworthy was the activity against MRSA with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) ranging from 0.39 to 0.78 microg/ml. As shown for S. pyogenes, no surviving cells were detected within 5 and 6h after treatment with the compound at 8MBC and 4MBC concentrations, respectively. Rhodomyrtone displays no bacteriolytic activity, as determined by measurement of the optical density at 620 nm. A rhodomyrtone killing test with S. mutans using phase contrast microscopy showed that this compound caused a few morphological changes as the treated cells were slightly changed in color and bigger than the control when they were killed. Taken together, the results support the view that rhodomyrtone has a strong bactericidal activity on gram-positive bacteria, including major pathogens.

Inhibitory effect of Eleutherine americana Merr. extract on Staphylococcus aureus isolated from food

About 106 samples of ready-to-eat foods were purchased over a period of 3 mo out of which 76 (71.69%) were contaminated with Staphylococcus aureus. S. aureus isolated from the food samples were characterized phenotypically using traditional biochemical methods. Ninety-four percent of the isolates were mannitol fermenters, 86% positive for coagulase test, while 80% produced lipase enzyme. Antibiotic susceptibility test revealed that 21% and 63% of the food isolates were resistant to oxacillin and penicillin, respectively. The antibacterial activity of the bulb of Eleutherine americana used in Thai cuisine was investigated by agar disc diffusion using 2.5 mg of the crude extract and produced inhibition zone between 14.5 and 15.7 mm, while the minimum inhibitory concentration (MIC) value ranged from 0.06 to 1.00 mg/mL on both food isolates and reference strains. Growth curve in the presence of the crude ethanol extract at 4 MIC showed bacteriostatic effect by 5 log reduction relative to the control. Partially purified fractions tentatively identified by column chromatography were suspected to be responsible for the antibacterial property. This study suggests that E. americana bulb has potential for application as a natural preservative in foods.

Assessment of antistaphylococcal activity of partially purified fractions and pure compounds from Eleutherine americana

Ready-to-eat foods were investigated for contamination with methicillin-resistant Staphylococcus aureus (MRSA), and the partially purified fractions from the bulb of Eleutherine americana were evaluated for their anti-MRSA activity. Partially purified fractions Ea6.3 and Ea9 demonstrated good antibacterial activity with a MIC of 125 to 500 microg/ml and MBC of 250 to > or =1000 microg/ml against all the food isolates. Fraction Ea6.3 produced a MIC and MBC of 250 and 500 microg/ml, respectively, whereas fraction Ea9 yielded MIC and MBC of 125 and > or =1000 microg/ml, respectively, against the enterotoxin-producing reference strains. Growth curves in the presence of fraction Ea6.3 at 4 x MIC resulted in total elimination of all the test strains between 20 and 24 h, while fraction Ea9 reduced bacterial population by at least 6 log relative to the control. The partially purified fractions were further purified to obtain pure compounds identified as eleutherol, eleutherin, isoeleutherin, hongconin, two anthraquinones, and elecanacin. The antibacterial activities of these compounds were also investigated; they produced MICs ranging from 31.25 to > or =1000 microg/ml. This study suggests that E. americana crude extract or its partially purified fractions have potentials for application as natural food preservatives.

Effects of compounds from Garcinia mangostana on inflammatory mediators in RAW264.7 macrophage cells

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit hull of Garcinia mangostana Linn. has been used in Thai traditional medicine for treatment of abscess and skin infection.

AIM OF THE STUDY

The mangosteen fruit hull and its compounds were carried out to investigate for anti-inflammatory activity.

MATERIAL AND METHODS

The extract of Garcinia mangostana together with alpha- and gamma-mangostins were tested for anti-inflammatory effect against lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-alpha) and interleukin-4 (IL-4) releases as well as their mechanisms in transcriptional levels using RAW264.7 macrophage cells.

RESULTS

Mangosteen extract possessed potent NO inhibitory effect with an IC50 value of 1.0 microg/ml. The isolated compounds from the extract including alpha-mangostin and gamma-mangostin, possessed marked inhibitory effect against NO release with IC50 values of 3.1 and 6.0 microM, respectively. The extract exhibited potent inhibitory effect on PGE2 release (IC50=6.0 microg/ml), whereas those of alpha- and gamma-mangostins were 13.9 and 13.5 microM, respectively. However, mangostins possessed only moderate effects towards TNF-alpha and IL-4 releases with IC50 values ranging from 31.8 to 64.8 microM. Both extract and alpha-mangostin suppressed transcription of gene encoding inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in dose-dependent manners, whereas gamma-mangostin had only an inhibitory effect on transcription of iNOS.

CONCLUSION

The present study may support the Thai traditional use of Garcinia mangostana fruit hull for treatment of inflammatory-related diseases through the inhibition of NO and PGE2 releases, but moderate effect through TNF-alpha and IL-4.

Morelloflavone blocks injury-induced neointimal formation by inhibiting vascular smooth muscle cell migration

BACKGROUND

In-stent restenosis, or renarrowing within a coronary stent, is the most ominous complication of percutaneous coronary intervention, caused by vascular smooth muscle cell (VSMC) migration into and proliferation in the intima. Although drug-eluting stents reduce restenosis, they delay the tissue healing of the injured arteries. No promising alternative anti-restenosis treatments are currently on the horizon.

METHODS

In endothelium-denudated mouse carotid arteries, oral morelloflavone-an active ingredient of the Thai medicinal plant Garcinia dulcis-significantly decreased the degree of neointimal hyperplasia, without affecting neointimal cell cycle progression or apoptosis as evaluated by Ki-67 and TUNEL staining, respectively. At the cellular level, morelloflavone robustly inhibited VSMC migration as shown by both scratch wound and invasion assays. In addition, morelloflavone prevented VSMCs from forming lamellipodia, a VSMC migration apparatus. Mechanistically, the inhibition by morelloflavone of VSMC migration was through its negative regulatory effects on several migration-related kinases, including FAK, Src, ERK, and RhoA. Consistently with the animal data, morelloflavone did not affect VSMC cell cycle progression or induce apoptosis.

RESULTS

These data suggest that morelloflavone blocks injury-induced neointimal hyperplasia via the inhibition of VSMC migration, without inducing apoptosis or cell cycle arrest.

GENERAL SIGNIFICANCE

We propose morelloflavone to be a viable oral agent for the prevention of restenosis, without compromising effects on the integrity and healing of the injured arteries.

Inhibition of human lipoprotein oxidation by morelloflavone and camboginol fromGarcinia dulcis

A biflavonoids, morelloflavone (1) and a prenyltated xanthone, camboginol (2), isolated from the fruits of Garcinia dulcis (Roxb.) Kurz., exhibited strong antioxidation effects in both Fe2+ -mediated and non-metal induced human low-density lipoprotein (LDL) oxidations. However, a well-known antioxidant, alpha-tocopherol (vitamin E), was found less potent than both compounds based on the same test systems.

Prenylated xanthones as potential antiplasmodial substances

Mangostin, the major xanthone of Garcinia mangostana, and a series of synthetic derivatives were investigated for their in vitro antiplasmodial activity against Plasmodium falciparum. Mangostin itself showed moderate activity, but prenylated xanthones containing alkylamino functional groups exhibited quite potent antiplasmodial activity. Some structure-activity relationships are proposed.

Xanthone derivatives from Cratoxylum cochinchinense roots

Two xanthones and two caged-prenylated xanthones, named cochinchinones A-D, respectively, and a synthetically known caged-prenylated xanthone, together with seven known compounds were isolated from the roots of Cratoxylum cochinchinense (Lour.) Blume. Their structures were assigned on the basis of analyses of spectroscopic data. Some of the compounds exhibited effective antioxidative properties.

Phenolic compounds from the flowers of Garcinia dulcis

Dulcisxanthones C-F and dulcinone together with 22 known compounds were isolated from the flowers of Garcinia dulcis. Their structures were determined by spectroscopic methods. The abilities of some of these compounds to act as radical scavengers and antibacterial agents were investigated.

Phenolic compounds from the fruit of Garcinia dulcis

Dulcinoside (1), dulcisisoflavone (2), dulcisxanthone A (3) and sphaerobioside acetate (6) together with 22 known compounds were isolated from the green fruit of G. dulcis. Dulcisflavan (4), dulcisxanthone B (5) and isonormangostin (7) together with 22 known compounds were isolated from the ripe fruit. Compounds 6 and 7 were synthetic known compounds. Their structures were determined by spectroscopic methods. The radical scavenging and antibacterial activities of some of the compounds were investigated.

Xanthones from Garcinia cowa Roxb. latex

Five xanthones named cowagarcinone A-E and six previously reported xanthones were isolated from the latex of Garcinia cowa Roxb. Their structures were determined on the basis of spectroscopic analysis. The crude latex and the isolated compounds were investigated for their radical scavenging activities.

A benzil and isoflavone derivatives from Derris scandens Benth

A benzil derivative: scandione, 2',2"-dihydroxy-4'-methoxy-4",5"-methylenedioxybenzil and two isoflavones: scandenal, 3'-formyl-4',5-dihydroxy-2",2"-dimethylchromeno-[6,7:5",6"]isoflavone and scanderone, 4',5-dihydroxy-3'-prenyl-2",2"-dimethylchromeno-[7,8:6",5"]isoflavone together with fifteen known compounds were isolated from the stem of D. scandens. Their structures were determined by spectroscopic methods. Radical scavenging, antibacterial and hypertensive activities of some of the compounds were investigated.

Inhibition of lipoprotein oxidation by prenylated xanthones derived from mangostin

Oxidative damage is thought to play a critical role in cardiovascular and other chronic diseases. This has led to considerable interest in the antioxidant activity of dietary compounds. Flavonoids have received the most attention and much is known about the structural requirements for antioxidant activity. However, little is known about the antioxidant activity of other plant derived phenolic compounds such as the xanthones. We have previously shown that the prenylated xanthone, mangostin, can inhibit the oxidation of low density lipoprotein. In order to examine the effects of structure modification on antioxidant activity of this class of compound we have prepared a number of derivatives of mangostin and tested antioxidant activity in an isolated LDL and plasma assay. The results of this study show that structural modification of mangostin can have a profound effect on antioxidant activity. Derivatisation of the C-3 and C-6 hydroxyl groups with either methyl, acetate, propane diol or nitrile substantially reduces antioxidant activity. In contrast, derivatisation of C-3 and C-6 with aminoethyl derivatives enhanced antioxidant activity, which may be related to changes in solubility. Cyclisation of the prenyl chains had little influence on antioxidant activity.

Inhibition of eukaryote protein kinases and of a cyclic nucleotide-binding phosphatase by prenylated xanthones

A series of prenylated xanthones are variously potent inhibitors of the catalytic subunit (cAK) of rat liver cyclic AMP-dependent protein kinase (PKA), rat brain Ca2+ and phospholipid-dependent protein kinase C (PKC), chicken gizzard myosin light chain kinase (MLCK), wheat embryo Ca2+-dependent protein kinase (CDPK) and potato tuber cyclic nucleotide-binding phosphatase (Pase). The prenylated xanthones examined are mostly derivatives of alpha-mangostin in which the 3-hydroxyl and 6-hydroxyl are variously substituted with groups R or R', respectively, or derivatives of 3-isomangostin (mangostanol) in which the 9-hydroxyl is substituted with groups R' or the prenyl side chain is modified. The most potent inhibitors of cAK have non-protonatable and relatively small R' and R groups. Conversely, the most potent inhibitors of PKC and MLCK have bulkier and basic R' groups. Some prenylated xanthones are also potent inhibitors of CDPK. PKC and cAK are competitively inhibited by particular prenylated xanthones whereas the compounds that are the most potent inhibitors of MLCK and CDPK are non-competitive inhibitors. Prenylated xanthones having relatively small and non-protonatable R' and R groups inhibit a high-affinity cyclic nucleotide binding Pase in a non-competitive fashion.

Bicyclomangostin: a New Acid-Catalysed Cyclization Product from Mangostin

Cyclization of mangostin with p-toluenesulfonic acid gave 1-isomangostin, 3-isomangostin, and a new cyclization product, bicyclomangostin (4). The structure of bicyclomangostin was determined by spectroscopic and X-ray crystallographic studies. The methyl ether derivatives (8) and (9) or (10) were produced on methylation of bicyclomangostin, depending on the method used.

A triterpenoid saponin from Maesa ramentacea

The structure of a piscicidal triterpenoid saponin (saponin A) isolated from the leaves of Maesa ramentacea has been shown to be 3-O-[[(alpha-rhamnopyranosyl (1-->2)-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl (1-->3)]-[beta-D-glucopyranosyl(1-->2)]-beta-D-glucuronopyranosyl] barringtogenol C21, 22-O-diangeloate. Extensive use was made of homo- and heteronuclear 2D NMR techniques.