Development of a radiochemical cyclooxygenase-1 and -2 in vitro assay for identification of natural products as inhibitors of prostaglandin biosynthesis

Inhibition of cyclooxygenase and EP3 receptor improved long term potentiation in a rat organotypic hippocampal model of repeated blast traumatic brain injury

Blast-induced traumatic brain injury (bTBI) is a health concern in military service members who are exposed to multiple blasts throughout their training and deployment. Our group has previously reported decreased long term potentiation (LTP) following repeated bTBI in a rat organotypic hippocampal slice culture (OHSC) model. In this study, we investigated changes in inflammatory markers like cyclooxygenase (COX) and tested the efficacy of COX or prostaglandin EP3 receptor (EP3R) inhibitors in attenuating LTP deficits. Expression of COX-2 was increased 48 h following repeated injury, whereas COX-1 expression was unchanged. EP3R expression was upregulated, and cyclic adenosine monophosphate (cAMP) concentration was decreased after repeated blast exposure. Post-traumatic LTP deficits improved after treatment with a COX-1 specific inhibitor, SC-560, a COX-2 specific inhibitor, rofecoxib, a pan-COX inhibitor, ibuprofen, or an EP3R inhibitor, L-798,106. Delayed treatment with ibuprofen and L-798,106 also prevented LTP deficits. These findings suggest that bTBI induced neuroinflammation may be responsible for some functional deficits that we have observed in injured OHSCs. Additionally, COX and EP3R inhibition may be viable therapeutic strategies to reduce neurophysiological deficits after repeated bTBI.

Integracides: Tetracyclic Triterpenoids from Fusarium sp.-Their 5-Lipoxygenase Inhibitory Potential and Structure-Activity Relation Using In Vitro and Molecular Docking Studies

Inflammation is a complicated disorder that is produced as a result of consecutive processes. 5-LOX (5-lipoxygenase) is accountable for various inflammation mediators and leukotrienes synthesis, and its inhibition is the target of anti-inflammation therapeutics. Fungi have acquired enormous attentiveness because of their capability to biosynthesize novel bio-metabolites that reveal diversified bio-activities. A new tetracyclic triterpenoid, integracide L (1), along with integracides B (2) and F (3), were separated from Mentha longifolia-associated Fusarium sp. (FS No. MAR2014). Their structures were verified utilizing varied spectral analyses. The isolated metabolites (1-3), alongside the earlier reported integracides G (4), H (5), and J (6), were inspected for 5-LOX inhibition capacity. Interestingly, 1-6 possessed marked 5-LOX inhibition potentials with IC₅₀s ranging from 1.18 to 3.97 μM compared to zileuton (IC₅₀ 1.17 µM). Additionally, molecular docking was executed to examine the interaction among these metabolites and 5-LOX, as well as to validate the in vitro findings. The docking study revealed their inhibitory activity interactions in the binding pocket. These findings highlighted the potential of integracides as lead metabolites for anti-inflammation drug discovery.

Genotoxic effects of Dukhan: A smoke bath from the wood of Acacia seyal used traditionally by Sudanese women

ETHNOBOTANICAL RELEVANCE

Smoke from the wood of Acacia seyal Delile has been used by Sudanese women for making a smoke bath locally called Dukhan. The ritual is performed to relieve rheumatic pain, smooth skin, heal wounds and achieve general body relaxation.

AIM OF THE STUDY

The present study was designed to investigate the in vitro anti-inflammatory effect of the smoke condensate using cyclooxygenase -1 (COX-1) and -2 (COX-2) as well as its potential genotoxic effects using the bacterial-based Ames test and the mammalian cells-based micronucleus/cytome and comet assays.

MATERIAL AND METHODS

The smoke was prepared in a similar way to that commonly used traditionally by Sudanese women then condensed using a funnel. Cyclooxygenase assay was used to evaluate its in vitro anti-inflammatory activity. The neutral red uptake assay was conducted to determine the range of concentrations in the mammalian cells-based assays. The Ames, cytome and comet assays were used to assess its potential adverse (long-term) effects.

RESULTS

The smoke condensate did not inhibit the cyclooxygenases at the highest concentration tested. All smoke condensate concentrations tested in the Salmonella/microsome assay induced mutation in both TA98 and TA100 in a dose dependent manner. A significant increase in the frequency of micronucleated cells, nucleoplasmic bridges and nuclear buds was observed in the cytome assay as well as in the % DNA damage in the comet assay.

CONCLUSIONS

The findings indicated a dose dependent genotoxic potential of the smoke condensate in the bacterial and human C3A cells and may pose a health risk to women since the smoke bath is frequently practised. The study highlighted the need for further rigorous assessment of the risks associated with the smoke bath practice.

Ibuprofen does not impair skeletal muscle regeneration upon cardiotoxin-induced injury

Muscle regeneration is regulated through interaction between muscle and immune cells. Studies showed that treatment with supra-physiological doses of Non-Steroidal Anti-Inflammatory Drug (NSAID) abolished inflammatory signaling and impaired muscle recovery. The present study examines the effects of pharmacologically-relevant NSAID treatment on muscle regeneration. C57BL/6 mice were injected in the tibialis anterior (TA) with either PBS or cardiotoxin (CTX). CTX-injected mice received ibuprofen (CTX-IBU) or were untreated (CTX-PLAC). After 2 days, Il-1beta and Il-6 expression was upregulated in the TA of CTX-IBU and CTX-PL vs. PBS. However, Cox-2 expression and macrophage infiltration were higher in CTX-PL vs. PBS, but not in CTX-IBU. At the same time, anabolic markers were higher in CTX-IBU vs. PBS, but not in CTX-PL. Nevertheless, ibuprofen did not affect muscle mass or muscle fiber regeneration. In conclusion, mild ibuprofen doses did not worsen muscle regeneration. There were even signs of a transient improvement in anabolic signaling and attenuation of inflammatory signaling.

Anti-Inflammatory and Anticoagulant Activities of Synthesized NSAID Prodrug Esters

Paracetamol with ibuprofen or with naproxen are frequently prescribed by doctors in combination. It was found that patients using a combination of NSAID like acetaminophen and ibuprofen experienced less pain. Patients are more compliant if these two drugs are combined in an ester form and given in one dosage form. The esterified prodrugs are hydrolyzed in humans to their active forms. In this study, two esters of paracetamol combined with ibuprofen and naproxen were synthesized as prodrugs. The physiochemical properties of these products were identified. Moreover, the bioactivities of these prodrugs were tested for its anti-inflammatory and anticoagulant activities. The results showed an improved COX inhibition and anticoagulant activity compared with their parent drugs. The synthesized drugs are expected to improve patient's compliance in terms of administration frequency and will have better pharmacokinetic properties with fewer side effects.

Medicinal plants with anti-inflammatory activities from selected countries and regions of Africa

Various nonsteroidal anti-inflammatory drugs have been shown to reduce pain and inflammation by blocking the metabolism of arachidonic acid by isoform of cyclooxygenase enzyme, thereby reducing the production of prostaglandin. Sadly, there are many side effects associated with the administration of nonsteroidal anti-inflammatory drugs. However, there are medicinal plants with anti-inflammatory therapeutic effects with low or no side effects. The Afri-can continent is richly endowed with diverse medicinal plants with anti-inflammatory activities that have been shown to be effective in the treatment of inflammatory conditions in traditional medicine. Interestingly, scientists have examined some of these African medicinal plants and documented their biological and therapeutic activities. Unfortunately, medicinal plants from different countries in Africa with anti-inflammatory properties have not been documented in a single review paper. It is important to document the ethnobotanical knowledge and applications of anti-inflammatory medicinal plants from selected countries representing different regions of the African continent. This paper therefore documents anti-inflammatory activities of various medicinal plants from different geographical regions of Africa with the aim of presenting the diversity of medicinal plants that are of traditional or therapeutic use in Africa.

Wine Components Inhibit Cholera Toxin-Induced Intestinal Secretion in Rats

Gut bacterial toxins contribute to many diseases, including diarrhea. Cholera represents a life-threatening form of enterotoxin-induced diarrhea caused by infection with the bacterium Vibrio cholerae. Diarrhea results from the prosecretory actions of a bacterial enterotoxin. The aim of this study was to identify dietary compounds that antagonize the intestinal secretory actions of cholera toxin and which might be useful in diarrhea prevention and treatment. Rat small intestine (jejunum) was ligated in vivo and separate segments of small bowel were randomly injected with various dietary compounds in the presence and absence of cholera toxin. The secretory response to cholera toxin was assessed by measuring the amount of fluid secreted into the bowel segments. Compared to controls, red wine and wine components significantly inhibited the small intestinal secretory response to cholera toxin. Grape juice, ethanol (12%), and World Health Organization rehydration fluid had lesser antisecretory effects. These novel results demonstrate that nonethanol components of wine possess antisecretory effects. These substances may be useful in treating gut enterotoxin-mediated diseases such as cholera.

Synthesis and Evaluation of Novel Erlotinib-NSAID Conjugates as More Comprehensive Anticancer Agents

A series of novel anticancer agents were designed and synthesized based on coupling of different nonsteroidal anti-inflammatory drugs (NSAIDs) with the epidermal growth-factor receptor (EGFR) tyrosine kinase inhibitor, erlotinib. Both the antiproliferative and pharmacokinetic activity of the target compounds were evaluated using HCC827 and A431 tumor cell lines. Among the derivatives made, compounds 10a, 10c, and 21g showed superb potency, comparable to that of erlotinib. Furthermore, preliminary SAR analysis showed that when the NSAIDs were conjugated via linkage to C-6 OH versus linkage to C-7 OH of the quinazoline nucleus, superior anticancer activity was achieved. Finally, the in vitro pharmacokinetic profile of several conjugates demonstrated the desired dissociation kinetics as the coupled molecules were effectively hydrolyzed, releasing both erlotinib and the specific NSAID in a time-dependent manner. The conjugation strategy represents a unique and simplified approach toward combination therapy, particularly for the treatment of cancers where both EGFR overexpression and inflammation play a direct role in disease progression.

Effect of cocoa products and flavanols on platelet aggregation in humans: a systematic review

The percentage of healthy subjects with decreased platelet aggregation after bolus consumption of cocoa products is reported.

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

ETHNOPHARMACOLOGICAL IMPORTANCE

Gastrointestinal disorders and infections are the major pathoaetiologies of diarrhoea causing many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat infectious diseases including diarrhoea and many other ailments by rural people in Africa and Asia. Much of the work done to date on this genus was on the non-polar or intermediate polarity components. Some parameters that may cause diarrhoea and the evaluation of more polar extracts have apparently not been investigated.

AIMS

The polar components were extracted and fractionated by solvent-solvent fractionation to yield fractions with different polarities. The activity of these fractions on different parameters that could be involved in factors associated with diarrhoea was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals.

MATERIALS AND METHODS

Phenolic-enriched leaf extracts of Combretum bracteosum (COB), Combretum padoides (COP), Combretum vendae (COV) and Combretum woodii (COW) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. Acetone was removed from a portion of the 70% acetone extract and it was sequentially treated by solvent-solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures The antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid (ABTS(+)) radical scavenging, ferric reducing antioxidant power (FRAP) methods and lipid peroxidation inhibitory capacity standard methods. The ferric reducing antioxidant activities of the fractions were also determined. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out.

RESULT

Some of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21-12µg/ml (COP), 0.25-16µg/ml (COV), 0.33-9.41µg/ml (COW) and 4.97-85µg/ml (COB) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28-1.51 and 1.02-1.19µg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 µg/ml. COP had the highest antibacterial activity with MICs ranging between 19-2500µg/ml, followed by COV with MICs ranging between 39-625µg/ml; COW and COB had similar MICs ranging between 39-2500µg/ml. COP also had the highest antifungal activity with MICs between 19-625µg/ml. The MIC for COW and COV ranged from 19 to 1250 µg/ml. COB had the lowest antifungal activity (MIC values were between 39 and 625 µg/ml). In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentration of hydrolysable tannin (gallotannin). A good correlation (R(2)= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity.

CONCLUSION

The results obtained in this study with more polar extracts indicate that the use of extracts of these plant species as antidiarrhoeal agents may have a scientific basis. The extractant used here extracted a much higher percentage of the phytochemicals than acetone. It was better for isolating antioxidant compounds (polar) but not good for isolating antimicrobial compounds (non-polar) from the same species compared to acetone, ethyl acetate, dichloromethane, and hexane.

Antiinflammatory and neurological activity of pyrithione and related sulfur-containing pyridine N-oxides from Persian shallot (Allium stipitatum)

ETHNOPHARMACOLOGICAL RELEVANCE

Persian shallot (Allium stipitatum) is a bulbous plant native to Turkey, Iran and Central Asia. It is frequently used in folk medicine for the treatment of a variety of disorders, including inflammation and stress. Antiinflammatory and neurological activities of pyrithione and four related sulfur-containing pyridine N-oxides which are prominent constituents of Allium stipitatum were tested.

METHODS

The antiinflammatory activity was tested by the ability of the compounds to inhibit cyclooxygenase (COX-1 and COX-2), whereas the neurological activities were evaluated by assessing the compounds ability to inhibit monoamine oxidase-A (MAO-A) and acetylcholinesterase (AChE). The compounds׳ affinity for the serotonin transport protein (SERT) and the GABAA-benzodiazepine receptor were also investigated.

RESULTS

2-[(Methylthio)methyldithio]pyridine N-oxide showed very high antiinflammatory effects which are comparable with those of common pharmaceuticals (IC₅₀ of 7.8 and 15.4 µM for COX-1 and COX-2, respectively). On the other hand, neurological activities of the compounds were rather modest. Some compounds moderately inhibited AChE (IC₅₀ of 104-1041 µM) and MAO-A (IC₅₀ of 98-241 µM) and exhibited an affinity for the SERT and GABAA-benzodiazepine receptor.

CONCLUSIONS

Our findings may help to rationalize the wide use of Persian shallot for the treatment of inflammatory disorders.

Bioassays in natural product research - strategies and methods in the search for anti-inflammatory and antimicrobial activity

INTRODUCTION

Identifying bioactive molecules from complex biomasses requires careful selection and execution of relevant bioassays in the various stages of the discovery process of potential leads and targets.

OBJECTIVE

The aim of this review is to share our long-term experience in bioassay-guided isolation, and mechanistic studies, of bioactive compounds from different organisms in nature with emphasis on anti-inflammatory and antimicrobial activity.

METHODS

In the search for anti-inflammatory activity, in vivo and in vitro model combinations with enzymes and cells involved in the inflammatory process have been used, such as cyclooxygenases, human neutrophils and human cancer cell lines. Methods concerning adsorption and perforation of bacteria, fungi, human cells and model membranes, have been developed and optimised, with emphasis on antimicrobial peptides and their interaction with the membrane target, in particular their ability to distinguish host from pathogen.

RESULTS

A long-term research has provided experience of selection and combination of bioassay models, which has led to an increased understanding of ethnopharmacological and ecological observations, together with in-depth knowledge of mode of action of isolated compounds.

CONCLUSION

A more multidisciplinary approach and a higher degree of fundamental research in development of bioassays are often necessary to identify and to fully understand the mode of action of bioactive molecules with novel structure-activity relationships from natural sources.

Characterization of inflamin, the first member of a new family of snake venom proteins that induces inflammation

Unlike other sea snakes, Aipysurus eydouxii feeds exclusively on fish eggs. This unusual feeding habit prompted us to search for unique transcripts in their venom glands. In the present study we expressed a novel cysteine-rich secretory protein containing 94 amino acid residues that was identified in its cDNA library. As it induced inflammation and writhing in animals, this protein was named inflamin. It induced two waves of prostanoid production. The first wave peaked at 10 min and 6-oxo PGF1α (prostaglandin F1α) (6-keto PGF1α) was the major product. The second wave, specifically of 6-oxo PGF1α and PGE2 (prostanglandin E2), started after 2 h. In RAW 264.7 cells, COX-1 (cyclo-oxygenase-1) activity showed a transient increase at 10 min and is responsible for the first wave, but its expression was unaffected. COX-2 was induced after 3 h and is responsible for the second wave. Using specific inhibitors, we showed that cPLA2 (calcium-dependent phospholipase A2), and not sPLA2 (secretory phospholipase A2), iPLA2 (calcium-independent phospholipase A2) or DAG (diacylglycerol) lipase, plays a key role in arachidonate release. The cPLA2 activity showed a transient increase of 62% at 10 min; this increase was due to its phosphorylation and not due to an increase in its expression. Thus inflamin, the first member of a new family of snake venom proteins, leads to an increase in the cPLA2 and COX-1 activity resulting in inflammation and pain.

Ibuprofen inhibits colitis-induced overexpression of tumor-related Rac1b

The serrated pathway to colorectal tumor formation involves oncogenic mutations in the BRAF gene, which are sufficient for initiation of hyperplastic growth but not for tumor progression. A previous analysis of colorectal tumors revealed that overexpression of splice variant Rac1b occurs in around 80% of tumors with mutant BRAF and both events proved to cooperate in tumor cell survival. Here, we provide evidence for increased expression of Rac1b in patients with inflamed human colonic mucosa as well as following experimentally induced colitis in mice. The increase of Rac1b in the mouse model was specifically prevented by the nonsteroidal anti-inflammatory drug ibuprofen, which also inhibited Rac1b expression in cultured HT29 colorectal tumor cells through a cyclooxygenase inhibition.independent mechanism. Accordingly, the presence of ibuprofen led to a reduction of HT29 cell survival in vitro and inhibited Rac1b-dependent tumor growth of HT29 xenografts. Together, our results suggest that stromal cues, namely, inflammation, can trigger changes in Rac1b expression in the colon and identify ibuprofen as a highly specific and efficient inhibitor of Rac1b overexpression in colorectal tumors. Our data suggest that the use of ibuprofen may be beneficial in the treatment of patients with serrated colorectal tumors or with inflammatory colon syndromes.

Mechanism of action of indomethacin in indomethacin-responsive headaches

Indomethacin, as a member of the non-steroidal anti-inflammatory drug class, plays a special role in the treatment of headaches. By definition, it is completely efficacious in the treatment of the primary headache disorders paroxysmal hemicrania and hemicrania continua. Therefore, indomethacin is also used as a tool for differential diagnosis in headache clinics. Indomethacin has a clear action as a cyclooxygenase inhibitor. Additional mechanisms and interactions with cell signaling pathways and inflammatory pathways are considered in this article. However, it is not known what mechanism or interaction with pathophysiological mechanisms is the key to indomethacin's specific pharmacology in headache therapy. Focusing on headache therapy, we summarize the current knowledge of pharmacology, treatment options, and recommendations for the use of indomethacin in primary headaches. New findings from the field of headache research, as well as from Alzheimer's disease and cancer research on the pharmacological actions of indomethacin and their potential implications on the pathophysiology of indomethacin sensitive headaches, are discussed.

Bioassay-guided supercritical fluid extraction of cyclooxygenase-2 inhibiting substances in Plantago major L

INTRODUCTION

Selective extraction of plant materials is advantageous for obtaining extracts enriched with desired constituents, thereby reducing the need for subsequent chromatography purification. Such compounds include three cyclooxygenase-2 (COX-2) inhibitory substances in Plantago major L. targeted in this investigation: α-linolenic acid (α-LNA) (18:3 ω-3) and the triterpenic acids ursolic acid and oleanolic acid.

OBJECTIVE

To investigate the scope for tuning the selectivity of supercritical fluid extraction (SFE) using bioassay guidance, and Soxhlet extraction with dichloromethane as solvent as a reference technique, to optimise yields of these substances.

METHOD

Extraction parameters were varied to optimise extracts' COX-2/COX-1 inhibitory effect ratios. The crude extracts were purified initially using a solid phase extraction (SPE) clean-up procedure and the target compounds were identified with GC-MS, LC-ESI-MS and LC-ESI-MS² using GC-FID for quantification.

RESULTS

α-LNA was preferentially extracted in dynamic mode using unmodified carbon dioxide at 40°C and 172 bar, at a 0.04% (w/w) yield with a COX-2/COX-1 inhibitory effect ratio of 1.5. Ursolic and oleanolic acids were dynamically extracted at 0.25% and 0.06% yields, respectively, with no traces of (α-LNA) and a COX-2/COX-1-inhibitory effect ratio of 1.1 using 10% (v/v) ethanol as polar modifier at 75°C and 483 bar. The Soxhlet extracts had ursolic acid, oleanolic acid and αLNA yields up to 1.36%, 0.34% and 0.15%, respectively, with a COX-2/COX-1 inhibitory effect ratio of 1.2.

CONCLUSION

The target substances can be extracted selectively by bioassay guided optimisation of SFE conditions.

The antimicrobial, antioxidative, anti-inflammatory activity and cytotoxicity of different fractions of four South African Bauhinia species used traditionally to treat diarrhoea

ETHNOPHARMACOLOGICAL IMPORTANCE

Many Bauhinia species, including those indigenous to South Africa, are used in traditional medicine across the world for treating ailments such as gastrointestinal tract (GIT) disorders, diabetes, infectious diseases and inflammation.

AIMS

Several relevant aspects of different fractions of leaf extracts of Bauhinia bowkeri (BAB), Bauhinia galpinii (BAG), Bauhinia petersiana (BAP), and Bauhinia variegata (BAV) used in South African traditional medicine to alleviate diarrhoea related symptoms were evaluated.

MATERIALS AND METHODS

The antioxidative activities of the extracts were determined using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS(+)) radical scavenging and ferric reducing antioxidant power (FRAP) methods. In vitro antimicrobial activities of the extracts were determined against bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis) and clinical isolates of the opportunistic fungal strains (Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans) using a serial dilution microplate method. The polyphenolic contents were quantified using standard methods, and anti-inflammatory activities of the crude extracts were determined using the cyclooxygenase and soybean 15-lipoxygenase enzyme inhibitory assays. The safety of the extracts was evaluated by determining the cytotoxicity against Vero cell lines.

RESULTS

The acidified 70% acetone crude extract and their fractions had good antiradical potency against the DPPH and ABTS radicals. The methanol soluble portions of the butanol fractions were more potent (EC(50) ranges from 0.64 ± 0.05 to 1.51 ± 0.07 and 0.88 ± 0.18 to 1.49 ± 0.09 μg/ml against DPPH and ABTS radical respectively) compared to the standard, trolox and ascorbic acid (EC(50) ranges from 1.47 ± 0.24 to 1.70 ± 0.27 μg/ml) for both DPPH and ABTS. The crude extracts contained variable quantities of phenolic content. The crude extracts and their fractions had weak to good antimicrobial activities, inhibiting the growth of the organisms at concentrations ranging from 39 to 2500 μg/ml. The BAG crude extract and its fractions were the most active against the fungi (MICs ranging from 39 to 625 μg/ml) while the BAB extract and its fractions were the least active with the MICs ranging between 39 and 2500 μg/ml. Aspergillus fumigatus was the least susceptible fungus while Cryptococcus neoformans was the most susceptible. The phenolic-rich crude extracts of BAB, BAG, and BAP had moderate to good dose-dependent cyclooxygenase-1 enzyme inhibitory activity with inhibitions between 22.8% and 71.4%. The extracts were however, inactive against cyclooxygenase-2. The extracts had some level of cytotoxicity towards Vero cell lines, reducing cell viability to less than 10% at concentrations more than 50 μg/ml.

CONCLUSION

The biological activities observed in Bauhinia species provide a scientific basis for the use of the plants in traditional medicines to treat diseases with multi-factorial pathogenesis such as diarrhoea, with each aspect of activity contributing to the ultimate therapeutic benefit of the plants. However, the use of the phenolic-rich extracts of these plants to treat diarrhoea or any other ailments in traditional medicine needs to be monitored closely because of potential toxic effects and selective inhibition of COX-1 with the associated GIT injury.

Trihydroxyflavones with antioxidant and anti-inflammatory efficacy

The classical anti-inflammatory therapies are frequently ineffective and present numerous and severe side effects, especially in long term use, which requires the development of anti-inflammatory drugs with different scaffolds and mechanisms of action. Owing to the high antioxidant potential and anti-inflammatory activities already inferred for hydroxyflavones, we found it would be relevant to evaluate the anti-inflammatory potential of a series of trihydroxyflavones by testing their ability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) in cells and cell-free systems and to inhibit the proinflammatory pathways mediated by the enzymes cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), in which reactive species have a proven involvement. The tested trihydroxyflavones proved to be effective inhibitors of neutrophils' oxidative burst and were shown to scavenge different ROS and RNS in cell-free systems. The most active compound in the majority of the assays was 3,3',4'-trihydroxyflavone, which was somehow expected due to the presence of the ortho-dihydroxy in the B-ring, an important structural feature in terms of free radical scavenging activity. Additionally, the studied compounds were able to inhibit the production of leukotriene B(4) by 5-LOX in activated neutrophils. 3,5,7-Trihydroxyflavone was able to inhibit both COX-1 and COX-2, which makes it a dual inhibitor of COX and 5-LOX pathways and, therefore, a promising candidate for a new therapeutic option in the treatment of inflammatory processes.

Effects of nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NONO-NSAIDs) on melanoma cell adhesion

A new class of nitric oxide (NO•)-releasing nonsteroidal anti-inflammatory drugs (NONO-NSAIDs) were developed in recent years and have shown promising potential as NSAID substitutes due to their gentle nature on cardiovascular and gastrointestinal systems. Since nitric oxide plays a role in regulation of cell adhesion, we assessed the potential use of NONO-NSAIDs as anti-metastasis drugs. In this regard, we compared the effects of NONO-aspirin and a novel NONO-naproxen to those exerted by their respective parent NSAIDs on avidities of human melanoma M624 cells. Both NONO-NSAIDs, but not the corresponding parent NSAIDs, reduced M624 adhesion on vascular cellular adhesion molecule-1 (VCAM-1) by 20-30% and fibronectin by 25-44% under fluid flow conditions and static conditions, respectively. Only NONO-naproxen reduced (~56%) the activity of β1 integrin, which binds to α4 integrin to form very late antigen-4 (VLA-4), the ligand of VCAM-1. These results indicate that the diazeniumdiolate (NO•)-donor moiety is critical for reducing the adhesion between VLA-4 and its ligands, while the NSAID moiety can impact the regulation mechanism of melanoma cell adhesion.

Mitigation of DMBA-induced mammary carcinoma in experimental rats by antiangiogenic property of Kalpaamruthaa

Extra cellular matrix (ECM) and basement membrane (BM) are important layers that regulate cell structure, cell migration, and cellular proliferation. Degradation of both ECM and BM mediated by proteases favors the tumor invasion and promotes angiogenesis. Female Sprague-Dawley rats weighing 180 ± 10 g were categorized into 6 groups. Group-1 animals served as vehicle control. Group-2 to Group-4 animals were administered with 7,12-dimethylbenz(a)anthracene (25 mg/rat dissolved in olive oil, orally) on day 1 of experimental period to induce mammary carcinoma. (After 90 days, mammary carcinoma was confirmed by histopathological examination). Group-3 and Group-4 rats were subsequently treated with Semecarpus anacardium nut milk extract (SA) and Kalpaamruthaa (KA), respectively. Group-5 and Group-6 animals served as drug control for SA and KA, respectively. Pro-angiogenic factors like proteases, cyclooxygenase-2, and vascular endothelial growth factor were elevated in tumor-bearing animals and decreased in SA- and KA-supplemented rats. Increased levels of these angiogenic factors in tumor-bearing rats indicate the progression of mammary tumor. The decreased levels of these angiogenic in SA- and KA-treated rats may be due to the ameliorative effect of phenolic compounds such as flavonoids, tannins, and other compounds present in the drug.

A potential nitrergic mechanism of action for indomethacin, but not of other COX inhibitors: relevance to indomethacin-sensitive headaches

Non-steroidal anti-inflammatory drugs (NSAIDs) that act as cyclo-oxygenase (COX) inhibitors are commonly used in the treatment of a range of headache disorders, although their mechanism of action is unclear. Indomethacin is of particular interest given its very special effect in some primary headaches. Here the in vivo technique of intravital microscopy in rats has been utilised as a model of trigeminovascular nociception to study the potential mechanism of action of indomethacin. Dural vascular changes were produced using electrical (neurogenic) dural vasodilation (NDV), calcitonin gene-related peptide (CGRP) induced dural vasodilation and nitric oxide (NO) induced dural vasodilation using NO donors. In each of these settings the effect of intravenously administered indomethacin (5 mg kg(-1)), naproxen (30 mg kg(-1)) and ibuprofen (30 mg kg(-1)) was tested. All of the tested drugs significantly inhibited NDV (between 30 and 52%). Whilst none of them was able to inhibit CGRP-induced dural vasodilation, only indomethacin reduced NO induced dural vasodilation (35 ± 7%, 10 min post administration). We conclude NSAIDs inhibit release of CGRP after NDV without an effect on CGRP directly. Further we describe a differentiating effect of indomethacin inhibiting nitric oxide induced dural vasodilation that is potentially relevant to understanding its unique action in disorders such as paroxysmal hemicrania and hemicrania continua.

Measurement of cyclooxygenase inhibition using liquid chromatography-tandem mass spectrometry

Because cyclooxygenases (COX) convert arachidonic acid into pro-inflammatory cyclic endoperoxides, inhibition of these enzymes and especially the inducible COX-2 form is an important therapeutic approach to manage inflammatory diseases and possibly prevent cancer. Due to side effects of existing non-selective and COX-2 selective non-steroidal anti-inflammatory agents, the discovery of new COX inhibitors continues to be an area of active investigation. Since existing assays are slow or lack specificity, a liquid chromatography-tandem mass spectrometry (LC-MS-MS) based COX inhibition assay was developed and validated for the rapid and accurate quantitative analysis of the COX product prostaglandin E(2). The assay was validated using four COX inhibitors, celecoxib, indomethacin, resveratrol, and diclofenac that exhibit different selectivities towards COX-1 and COX-2. The IC(50) values of celecoxib and resveratrol for ovine and human COX-2 were compared, and the K(m) values were determined. Since considerable inter-species variation was observed, human COX-2 should be used for the discovery of COX inhibitors intended for human use. This sensitive and accurate LC-MS-MS based assay is suitable for the rapid screening of ligands for COX-1 and COX-2 inhibition and for IC(50) determinations.

In vitro biological activities of niloticane, a new bioactive cassane diterpene from the bark of Acacia nilotica subsp. kraussiana

ETHNOPHARMACOLOGICAL RELEVANCE

Acacia nilotica subsp. kraussiana was reported in African traditional medicine for the treatment of various ailments. Isolation of an active compound in this study from the bark extract may lead to the validation of its efficiency as a traditional crude drug.

AIMS OF THE STUDY

This study aimed to isolate active compound(s) from an ethyl acetate bark extract of Acacia nilotica subsp. kraussiana and to investigate some of its biological activity.

MATERIALS AND METHODS

The isolation process was carried out using bioassay-guided fractionation. The isolated compound was tested for antibacterial activity using the micro-dilution assay; anti-inflammatory activity using the COX-1 and COX-2 assays and investigated for inhibitory effect against acetylcholinesterase using the microplate assay.

RESULTS

A new bioactive compound was isolated and identified as a cassane diterpene, niloticane. Niloticane showed antibacterial activity against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus with MIC values of 4 and 8microg/mL, respectively. With Gram-negative bacteria, niloticane showed weak activity. MIC values obtained were 16 and 33microg/mL against Klebsiella pneumonia and Escherichia coli, respectively. In the cyclooxygenase test, niloticane possessed activity with IC50 values of 28 and 210microM against COX-1 and COX-2, respectively. IC50 values observed with indomethacin (positive control) were 3.6microM for COX-1 and 189microM for COX-2. In the acetylcholinesterase test, niloticane showed anti-cholinesterase activity with an IC50 value of 4microM. IC50 values obtained by the galanthamine (positive control) was 2.0microM.

CONCLUSION

The results obtained support the traditional uses of the bark of Acacia nilotica subsp. kraussiana in African traditional medicine for the treatment of some ailments that relate to microbial diseases, inflammation and central nervous system disorders.

Discovery of cyclooxygenase inhibitors from medicinal plants used to treat inflammation

Eleven authenticated botanicals used in the traditional Chinese medicine Huo-Luo-Xiao-Ling Dan were screened for ligands to cyclooxygenase (COX) using pulsed ultrafiltration liquid chromatography-mass spectrometry, and a mass spectrometry-based enzyme assay was used to determine the concentration of each of 17 ligands that inhibited COX-1 or COX-2 by 50% (IC(50)). Acetyl-11-keto-beta-boswellic acid, beta-boswellic acid, acetyl-alpha-boswellic acid, acetyl-beta-boswellic acid, and betulinic acid were COX-1 selective inhibitors with IC(50) values of approximately 10 microM. Senkyunolide O and cryptotanshinone were COX-2 selective inhibitors with IC(50) values of 5 microM and 22 microM, respectively. Roburic acid and phenethyl-trans-ferulate inhibited COX-1 and COX-2 equally. COX inhibition and the IC(50) values of most of these natural product ligands have not been reported previously.

Liquid chromatography/tandem mass spectrometry study of anti-inflammatory activity of plantain (Plantago L.) species

To evaluate anti-inflammatory activity of selected Plantago species (P. lanceolata L. and P. major L.) an optimized in vitro test for determination of cyclooxygenase-1 (COX-1) and 12-lipoxygenase (12-LOX) inhibition potency was undertaken. By using intact cell system (platelets) as a source of COX-1 and 12-LOX enzymes and highly sensitive and specific LC-MS/MS technique for detection of main arachidonic acid metabolites formed by COX-1 and 12-LOX, this test provides efficient method for evaluation of anti-inflammatory potential of plant extracts and isolated compounds. Our results validated the well-known COX-1 inhibitory activity of P. lanceolata and P. major methanol extracts (concentration required for 50% inhibition (IC(50)) was 2.00 and 0.65 mg/ml, respectively). Furthermore, 12-LOX inhibitory activity of examined extracts was reported for the first time (IC(50)=0.75 and 1.73 mg/ml for P. lanceolata and P. major, respectively). Although renowned inhibitors, such as acetylsalicylic acid and quercetin showed higher activity, this study verifies P. lanceolata and P. major as considerable anti-inflammatory agents.

Using N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) to assay cyclooxygenase activity in vitro

Prostaglandin endoperoxide synthase (PGH synthase), also known as cyclooxygenase (COX), was identified over 30 years ago and is the key enzyme in the pathway by which arachidonic acid is converted to the range of biologically active lipid mediators known as the prostanoids that participate in numerous physiological processes. The need for the development of new and improved COX inhibitors as potential therapeutics also drives the need for rapid, reliable, and inexpensive assays of COX activity. Colorimetric assays are often the preferred methods of enzyme analysis since they may be readily adapted to simple microplate formats that require relatively inexpensive and widely available instrumentation. The use of N,N,N cent,N cent-tetramethyl-p-phenylenediamine (TMPD) in high throughput microplate assays of COX activity could become the approach of choice in the screening of potential therapeutics that inhibit COX activity in vivo. Considering that TMPD is also a potential substrate for most, if not all, heme peroxidases, it is anticipated that this agent could find increasing application in the future.

Effect of cadmium accumulation on anti-inflammatory activity in two Eucomis species

Eucomis species (Hyacinthaceae) are widely used in South Africa as traditional medicine. The bulbs are used to alleviate a variety of symptoms including pain and inflammation. High levels of cyclooxygenase-1 and -2 (COX-1 and COX-2) inhibitory activity have been associated with certain Eucomis species. The aim of this study was to quantify cadmium(Cd) accumulation and examine its effect on COX-1 and COX-2 anti-inflammatory activity in Eucomis autumnalis and Eucomis humilis. Cadmium application at 2 mg L(-1) over a 6 week period revealed a substantial difference in total Cd accumulation in E. autumnalis and E. humilis (40.2 and 15.3 mg Cd kg-1, respectively). When supplied with Cd at 2 mg L(-1), E. humilis bulbous extracts showed lower inhibitory activity than the control for both COX-1 and COX-2. E. autumnalis bulbous extracts had greater COX-1 activity compared to the control. While COX-2 activity was suppressed. Researchers should be aware of the effect of environmental contaminants when reporting on biological activity of crude plant extracts.

Evaluation of antimicrobial and anti-inflammatory activities of seed extracts from six Nigella species

Seed extracts from six species of the genus Nigella (Family Ranunculaceae)-Nigella arvensis, Nigella damascena, Nigella hispanica, Nigella nigellastrum, Nigella orientalis, and Nigella sativa-obtained by successive extraction with n-hexane, chloroform, and methanol, were tested for their antimicrobial activity against 10 strains of pathogenic bacteria and yeast using the microdilution method as well as for anti-inflammatory properties by in vitro cyclooxygenase (COX)-1 and COX-2 assay. Chemical characterization of active extracts was carried out including free and fixed fatty acid analysis. Comparison of antimicrobial activity showed that N. arvensis chloroform extract was the most potent among all species tested, inhibiting Gram-positive bacterial and yeast strains with minimum inhibitory concentration (MIC) values ranging from 0.25 to 1 mg/mL. With the exception of selective inhibitory action of n-hexane extract of N. orientalis on growth of Bacteroides fragilis (MIC = 0.5 mg/mL), we observed no antimicrobial activity for other Nigella species. Anti-inflammatory screening revealed that N. sativa, N. orientalis, N. hispanica, N. arvensis n-hexane, and N. hispanica chloroform extracts had strong inhibitory activity (more than 80%) on COX-1 and N. orientalis, N. arvensis, and N. hispanica n-hexane extracts were most effective against COX-2, when the concentration of extracts was 100 microg/mL in both COX assays. In conclusion, N. arvensis, N. orientalis, and N. hispanica seeds, for the first time examined for antimicrobial and anti-inflammatory effects, revealed their significant activity in one or both assays.

Hydroxylated anthraquinones produced by Geosmithia species

Geosmithia fungi are little known symbionts of bark beetles. Secondary metabolites of lilac colored species G. lavendula and other nine Geosmithia species were investigated in order to elucidate their possible role in the interactions of the fungi with environment. Hydroxylated anthraquinones (yellow, orange, and red pigments), were found to be the most abundant compounds produced into the medium during the submerged cultivation. Three main compounds were identified as 1,3,6,8-tetrahydroxyanthraquinone (1), rhodolamprometrin (1-acetyl-2,4,5,7-tetrahydroxyanthraquinone; 2), and 1-acetyl-2,4,5,7,8-pentahydroxyanthraquinone (3). Compounds 2 and 3 (representing the majority of produced metabolites) inhibited the growth of G+-bacteria Staphylococcus aureus and Bacillus subtilis with minimum inhibitory concentration of 64-512 microg/mL. Anti-inflammatory activity detected as inhibition of cyclooxygenase-2 was found only for compound 3 at 1 and 10 microg/mL. Compound 2 interfered with the morphology, compound 3 with cell-cycle dynamics of adherent mammalian cell lines.

Aspirin and indomethacin reduce lung inflammation of mice exposed to cigarette smoke

Neutrophil accumulation response to cigarette smoke (CS) in humans and animal models is believed to play an important role in pathogenesis of many tobacco-related lung diseases. Here we evaluated the lung anti-inflammatory effect of aspirin and indomethacin in mice exposed to CS. C57BL/6 mice were exposed to four cigarettes per day during 4 days and were treated i.p. with aspirin or indomethacin, administered each day 1h before CS exposure. Twenty four hours after the last exposure, cells and inflammatory mediators were assessed in bronchoalveolar lavage (BAL) fluid and the lungs used for evaluation of lipid peroxidation, p38 mitogen-activated protein kinase (MAPK) phosphorylation and nuclear transcription factor kappaB (NF-kappaB) activation. Exposure to CS resulted in a marked lung neutrophilia. Moreover, the levels of oxidative stress-related lipid peroxidation, prostaglandin E(2) (PGE(2)), interleukin 1beta (IL-1beta), monocyte chemotactic protein 1 (MCP-1), and activated NF-kappaB and p38 MAPK were greatly increased in CS group. Aspirin or indomethacin treatment led to a significant reduction of neutrophil influx, but only aspirin resulted in dramatic decrease of inflammatory mediators. Moreover, both drugs reduced lung p38 MAPK and NF-kappaB activation induced by CS. These results demonstrate that short-term CS exposure has profound airway inflammatory effects counteracted by the anti-inflammatory agents aspirin and indomethacin, probably through COX-dependent and -independent mechanisms.

In vitro anti-inflammatory activity of carvacrol: Inhibitory effect on COX-2 catalyzed prostaglandin E(2) biosynthesis

Possible anti-inflammatory effect of carvacrol was evaluated by in vitro cyclooxygenase-2 (COX-2) assay. Carvacrol inhibited production of prostaglandin E(2) catalysed by COX-2 with an IC(50) value of 0.8 microM what is practically the same concentration as the IC(50) obtained for the standard inhibitors indomethacin and NS-398 with values of 0.7 microM and 0.8 microM, respectively. The COX-1 was inhibited approximately at the same rate (IC(50) of 0.7 microM for carvacrol), which suggests non-selective inhibition of both enzyme isoforms. The results of the study demonstrate possible anti-inflammatory potential of this compound due to the inhibition of inducible COX-2 isoform.

Bioactivity and structure of biophenols as mediators of chronic diseases

Biophenols and their associated activity have generated intense interest. Current topics of debate are their bioavailability and bioactivity. It is generally assumed that their plasma concentrations are insufficient to produce the health benefits previously attributed to their consumption. However, data on localized in vivo concentrations are not available and many questions remain unanswered. Potential mechanisms by which they may exert significant bioactivity are discussed together with structure activity relationships. Biophenols are highly reactive species and they can react with a range of other compounds. Products of their reaction when functioning as antioxidants are examined.

Potent inhibition of in vivo angiogenesis and tumor growth by a novel cyclooxygenase-2 inhibitor, enoic acanthoic acid

Recent studies have shown that cyclooxygenase-2 is crucially involved in angiogenesis. In fact, several specific cyclooxygenase-2 inhibitors suppress angiogenesis in vivo, suggesting that cyclooxygenase-2 is a promising target for the treatment of angiogenesis-related diseases. In the present study we investigate the activity of a new cyclooxygenase-2 inhibitor, enoic acanthoic acid (EAA), which was synthesized from the known natural cyclooxygenase-2 inhibitor, acanthoic acid (AA). The demonstration of a high correlation between EAA- and celecoxib-induced gene expression signatures in microarray experiments validated the specificity of EAA on cyclooxygenase-2. In angiogenesis assays, EAA potently inhibited basic fibroblast growth factor-induced invasion and tube formation of bovine aortic endothelial cells in vitro. Moreover, this inhibitor prevented both neovascularization of the chorioallantoic membrane of growing chick embryo and basic fibroblast growth factor-induced mouse corneal angiogenesis in vivo. EAA also significantly suppressed the growth of bladder tumors in a mouse model, showing better antitumor activity than celecoxib. Furthermore, gelatin zymogram analysis revealed that EAA potently inhibited the activities of matrix metalloproteinase 2 and 9. These results clearly demonstrate that EAA is a promising agent for the prevention and treatment of angiogenesis-related diseases including cancer.

Anti-inflammatory activity of flavonoids from Populus davidiana

An in vitro bioassay-guide revealed that the methanol (MeOH) extract of the stem bark of Populus davidiana showed considerable inhibitory activity against cyclooxygenase (COX-1, COX-2). Continuous phytochemical study of the MeOH extract of this plant led to the isolation of ten flavonoids; sakuranetin (1), rhamnocitrin (2), 7-O-methylaromadendrin (3), naringenin (4), eriodictyol (5), aromadendrin (6), kaempferol (7), neosakuranin (8), sakuranin (9) and sakurenetin-5,4'-di-beta-D-glucopyranoside (10). Their structures were identified on the basis of their physicochemical and spectroscopic analyses. The isolated compounds, 1-10, were tested for their inhibitory activities against COX-1 and COX-2. Compound 7 was found to have potent inhibitory effect on COX-1 and a moderate effect on COX-2, meanwhile, compounds 1-6 showed moderate inhibition against COX-1 only. Moreover, compounds 5-8 exhibited suppressive effects on xanthine oxidase (XO). These results may explain, in part, the traditional uses of P. davidiana in ethnomedicine.

Aryl ketones from Acronychia pedunculata with cyclooxygenase-2 inhibitory effects

1-[2,4-Dihydroxy-6-methoxy-3,5-bis(3-methylbut-2-en-1-yl)phenyl]ethanone (1), and a new aryl ketone, named acrovestenol (2), were isolated as cyclooxygenase-2 (COX-2) inhibitory principles from a CH2Cl2 extract of the bark of Acronychia pedunculata by a bioassay-guided fractionation procedure. Compound 2 inhibited COX-2 with an IC50 value of 142.0+/-2.15 microM, compared to the COX-2 inhibitory reference compound NS-398 with an IC50 value of 11.3+/-1.12 microM. Compound 1 inhibited COX-2-catalyzed PG biosynthesis with 68% at a concentration of 500 microM. The structures were determined by UV, IR, and 1D- and 2D-NMR, including TOCSY, HSQC-DEPT, and HMBC, and MS investigations.

A novel electron paramagnetic resonance-based assay for prostaglandin H synthase-1 activity

Background

Prostaglandin H₂ synthase (PGHS) is the enzyme that catalyses the two-stage conversion of arachidonic acid to prostaglandin H₂ (PGH₂) prior to formation of prostanoids that are important in inflammation. PGHS isozymes (-1 and -2) are the target for nonsteroidal anti-inflammatory drugs (NSAIDs).

Given the rekindled interest in specific anti-inflammatory PGHS inhibitors with reduced unwanted side effects, it is of paramount importance that there are reliable and efficient techniques to test new inhibitors. Here, we describe a novel in vitro electron paramagnetic resonance (EPR)-based assay for measuring the activity of PGHS-1.

Methods

We validated a novel in vitro PGHS-1 activity assay based on the oxidation of spin-trap agent, 1-hydroxy-3-carboxy-pyrrolidine (CPH) to 3-carboxy-proxy (CP) under the action of the peroxidase element of PGHS-1. This quantifiable spin-adduct, CP, yields a characteristic 3-line electron paramagnetic (EPR) spectrum.

Results

The assay is simple, reproducible and facilitates rapid screening of inhibitors of PGHS-1. Aspirin (100 μM, 1 mM) caused significant inhibition of spin-adduct formation (72 ± 11 and 100 ± 16% inhibition of control respectively; P < 0.05). Indomethacin (100 μM) also abolished the signal (114 ± 10% inhibition of control; P < 0.01). SA and the PGHS-2-selective inhibitor, NS398, failed to significantly inhibit spin-adduct generation (P > 0.05).

Conclusion

We have demonstrated and validated a simple, reproducible, quick and specific assay for detecting PGHS-1 activity and inhibition. The EPR-based assay described represents a novel approach to measuring PGHS activity and provides a viable and competitive alternative to existing assays.

The anti-inflammatory properties of cocoa flavanols

Signs of chronic or acute inflammation have been demonstrated in most cardiovascular diseases of multifactorial pathogenesis, including atherosclerosis and chronic heart failure. The triggers and mechanisms leading to inflammation may vary between clinical conditions but they share many common mediators, including specific patterns of eicosanoid and cytokine production. Certain cocoa-based products can be rich in a subclass of flavonoids known as flavanols, some of which have been found in model systems to possess potential anti-inflammatory activity relevant to cardiovascular health. Indeed, experimental evidence demonstrates that some cocoa-derived flavanols can reduce the production and effect of pro-inflammatory mediators either directly or by acting on signaling pathways. However, it should be noted that the evidence for any beneficial effects of cocoa flavanols in providing a meaningful anti-inflammatory action has been gathered predominantly from in vitro experiments. Therefore, additional research in well-designed human clinical experiments, using cocoa properly characterized in terms of flavanol content, would be a welcome addition to the evidence base to determine unambiguously if this benefit does indeed exist. If so, then flavanol-rich cocoa could be a potential candidate for the treatment, or possibly prevention, of the broad array of chronic diseases that are linked to dysfunctional inflammatory responses.

Cytotoxic and COX-2 inhibitory constituents from the aerial parts ofAralia cordata

Three diterpenes (1, 8, and 9), three triterpenes (3, 4, and 7), one saponin (11), four sterols (2, 5, 6, and 12), and one cerebroside (10) were isolated from the EtOH extract of the aerial parts of Aralia cordata by repeated silica gel column chromatography. Their chemical structures were identified by comparing their physicochemical and spectral data with those published in literatures. All isolated compounds were evaluated for their cytotoxicity against L1210, K562, and LLC tumor cell lines using MTT assay. Of which, 3beta,5alpha-dihydroxy-6beta-methoxyergosta-7,22-diene (6) showed a potent cytotoxicity against all cell lines with IC50 values of 11.7, 11.9, and 15.1 microM, respectively, while compounds 1, 5, and 11 showed a moderate or weak cytotoxicity. These isolates were also examined for their inhibitory activity against COX-1 and COX-2. Although most compounds, except for 2, 10, and 12, showed a strong inhibitory activity against COX-1, they exhibited a moderate or weak inhibitory activity against COX-2.

Prostaglandin-H-synthase (PGHS)-1 and -2 microtiter assays for the testing of herbal drugs and in vitro inhibition of PGHS-isoenzyms by polyunsaturated fatty acids from Platycodi radix

In order to test inhibition of prostaglandin-H-synthase-1 and -2 (PGHS-1 and -2) by plant extracts, we have established two enzyme based in vitro assays with enzyme immunoassay (EIA) evaluation. The assays have been evaluated with known synthetic inhibitors and with plant extracts. In a screening of traditionally used Chinese herbs for anti-inflammatory activity, a series of n-hexane and dichloromethane extracts showed significant inhibitory effect in comparison with the known specific PGHS-2 inhibitors NS-398 (IC(50) = 2.6 microM) and nimesulide (IC(50) = 36 microM). The lipophilic extracts of the Chinese drug Jiengeng, the dried roots of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae), showed good inhibitory activity against both PGHS isoenzymes. The directly prepared DCM-extract exhibited better activity against PGHS-2 (IC(50) = 4.0 microg/ml) than against PGHS-1 (IC(50) = 17.6 microg/ml). We identified fatty acids as main active constituents and quantified them. Linoleic acid showed the highest content (ca. 20% of the dried extract) and a high and preferential PGHS-2 inhibitory activity (IC(50) (PGHS-1) = 20 microM; IC(50) (PGHS-2) = 2 microM). The comparison of the concentration of linoleic acid and the inhibitory activity of the direct DCM-extract showed, that linoleic acid is mainly responsible for the in vitro activity of the extract on PGHS-2.

Anolignan B: a bioactive compound from the roots of Terminalia sericea

Antibacterial bioassay-guided fractionation of an ethyl acetate root extract of Terminalia sericea led to the isolation of anolignan B. The isolated compound was further tested for anti-inflammatory activity using the cyclooxygenase enzyme assays (COX-1 and COX-2) and for potential mutagenic effects using the Ames test. In the antibacterial test, anolignan B showed activity against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration values obtained (MIC) ranged from 3.8 microg/ml against Bacillus subtilis (Gram-positive) to 31 microg/ml against Escherichia coli (Gram-negative). In the anti-inflammatory assays, anolignan B showed activity against both COX-1 (IC(50) = 1.5 mM) and COX-2 (IC(50) = 7.5 mM) enzymes. No potential mutagenic effects were observed in the Salmonella microsome assay (TA98). Isolation of anolignan B from Terminalia sericea as well as the antibacterial and anti-inflammatory activities observed in this study has not been reported previously.

Studies on antibacterial, anti-inflammatory and antioxidant activity of herbal remedies used in the treatment of benign prostatic hyperplasia and prostatitis

Crude water and ethanolic extracts of five herbal remedies reported in the literature for traditional treatment of benign prostatic hyperplasia (BPH) and/or prostatitis were investigated for their effect on hydroxyl scavenging activity, antibacterial activity and their ability to inhibit cyclooxygenase-1 and -2 (COX-1 and COX-2) catalysed prostaglandin biosynthesis. Both the water and ethanol extracts of Hypoxis hemerocallidea and Epilobium parviflorum inhibited the growth of Escherichia coli. All 10 extracts scavenged the hydroxyl radical but with various potencies (32-93%). Ethanolic extracts were the most active in inhibiting COX-1 catalysed prostaglandin biosynthesis. The ethanolic extract of Epilobium parviflorum showed inhibitory effects on both the COX-1 and -2 catalysed prostaglandin biosynthesis, inhibited growth of Escherichia coli and exerted antioxidant activity. Although these results support the traditional use of Epilobium parviflorum for treatment of prostatitis and BPH, further investigation is required, for this promising plant.

Antibacterial, anti-inflammatory, anti-cholinesterase and mutagenic effects of extracts obtained from some trees used in South African traditional medicine

Extracts obtained from 10 trees used in South African traditional medicine were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and anti-cholinesterase activities and investigated for potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and micro-dilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae. Of the 78 different plant extracts investigated, 80% showed activity against both Gram-positive and Gram-negative bacteria in the disc-diffusion assay. In the micro-dilution assay, 60% of the plant extracts showed minimum inhibitory concentration (MIC) values < or =1.56 mg ml(-1). The lowest MIC value (0.092 mg ml(-1)) was recorded for an ethyl acetate root extract of Acacia sieberiana against Staphylococcus aureus and Escherichia coli. In the anti-inflammatory assay, 70% of the investigated plant extracts (0.25 mg ml(-1)) inhibited both COX-1 and COX-2 activity (>50% and 70% for water and organic solvent extracts, respectively). An ethyl acetate leaf extract of Trichilia dregeana showed selective inhibition of COX-2 (81%). In the acetylcholinesterase inhibitory test, 21% of the plant extracts were active at a concentration < or =1 mg ml(-1) using the micro-dilution assay. The lowest IC(50) value was 0.04 mg ml(-1) obtained with an ethanol bark extract of Combretum kraussii. None of the investigated plants showed any potential mutagenic effects.

Human fecal water inhibits COX-2 in colonic HT-29 cells: role of phenolic compounds

The inducible enzyme cyclooxygenase-2 (COX-2) plays a major role in the regulation of inflammation and possibly in the development of colon cancer. The aim of the present study was to screen for COX-2 inhibitors in samples of fecal water (the aqueous phase of feces) and investigate whether phenolic compounds are responsible for any observed effects on COX-2. Volunteers (n = 20) were recruited and asked to supply a 24-h stool sample. Fecal water samples were prepared and analyzed by GC-MS for their content of phenolic compounds. These samples were also evaluated for their effects on COX-2 protein levels (Western blot) and prostaglandin (PG)E2 production in tumor necrosis-alpha-stimulated HT-29 cells and pure enzymatic activity in a COX-2-catalyzed prostaglandin biosynthesis in vitro assay. The major phenolic compounds identified were phenylpropionic acid, phenylacetic acid, cinnamic acid, and benzoic acid derivatives. Of 13 fecal water samples analyzed, 12 significantly decreased PGE2 production (range 5.4-39.7% inhibition, P-value < 0.05) compared with control cells and 13 of 14 samples analyzed decreased COX-2 protein levels in HT-29 cells (19-63% inhibition). Of the 20 fecal water samples, 2 also weakly inhibited enzymatic activity of purified COX-2 (22-24% inhibition). Three compounds identified in fecal water, 3-phenylpropionic acid, 3-hydroxyphenylacetic acid, and 3-(4-hydroxyphenyl)-propionic acid, decreased the protein level at 250 micromol/L (15-62% inhibition). This study shows for the first time that human fecal water contains components that can affect both the COX-2 protein level and enzymatic activity.

Anti-inflammatory activity and QSAR studies of compounds isolated from Hyacinthaceae species and Tachiadenus longiflorus Griseb. (Gentianaceae)

Twenty-two homoisoflavanones and structurally related compounds isolated from plants were screened for anti-inflammatory activity. Seventeen compounds were isolated from southern African Hyacinthaceae species, one from the Madagascan gentian Tachiadenus longiflorus Griseb. and four were of synthetic origin. Inhibition of prostaglandin synthesis in cell microsomal fractions was first evaluated, followed by screening for specific inhibition of isolated cyclooxygenase enzymes (COX-1 and COX-2). Six homoisoflavanone and structurally related compounds showed significantly high levels of anti-inflammatory activity in the microsomal fraction assay. Only one compound exhibited a high level of anti-inflammatory activity in the COX-1 enzyme assay and no significant activity was detected in the COX-2 enzyme assay. Biological screening was followed by a computer-based quantitative structure-activity relationship (QSAR) study. The physicochemical descriptors: strain energy, heat of formation, volume, surface area, aqueous phase energy, dipole moment, enthalpy, entropy, molar refractivity, parachor, density, refractive index, surface tension, polarizability, logP, Van der Waals interaction energy, Coulombic interaction energy and nonbonded interaction energy were used to characterize the structures of the homoisoflavanones and structurally related compounds. This study produced three equations with significant prediction values for the anti-inflammatory activity of the compounds investigated. The derived models also provided valuable parameter guidelines for those properties influencing the anti-inflammatory activity of the studied compounds.