The dietary fibre and fermentability characteristics of local root crops and legumes were determined. Total, soluble and insoluble fibre were determined in six root crops (kamote, gabi, potato, tugi, ube, cassava) and ten legumes (mungbean, soyabean, peanut, pole sitao, cowpea, chickpea, green pea, lima bean, kidney bean and pigeon pea) using Association of Official Analytical Chemists methods. The dietary fibre from test foods was isolated and fermented in vitro using human faecal inoculum simulating conditions in the human colon. The SCFA, e.g. acetate, propionate, butyrate, produced after fibre fermentation was measured using HPLC. The dietary fibre content of root crops ranged from 4·6 to 13·5 g/100 g while legumes ranged from 20·9 to 46·9 g/100 g, suggesting that root crops and legumes are good sources of dietary fibre. Significant amounts of SCFA were produced after in vitro fermentation of the fibre isolate of both root crops and legumes. The best sources (as mmol/g fibre isolate) of acetate among the legumes were pole sitao (5·6 (sem 0·5)) and mungbean (5·3 (sem 0·1)) and among the root crops, tugi (2·5 (sem 0·4)) and cassava (2·4 (sem 0·1)); of propionate, kidney bean (7·2 (sem 1·5)) and pigeon pea (3·3 (sem 0·2)) for legumes, and tugi (1·8 (sem 0·2)) for root crops; and of butyrate, peanut (6·0 (sem 0·2)) and cowpea (5·4 (sem 0·2)) for legumes, and tugi (0·8 (sem 0·0)) and cassava (0·8 (sem 0·0)) for root crops. In conclusion, root crops and legumes are good sources of dietary fibre and produced SCFA after fibre fermentation, such as acetate, propionate and butyrate. SCFA production after in vitro fermentation can be estimated using human faecal inoculum and can be used to model the human colon.

In this issue of the British Journal of Nutrition, Mursu et al.(1) have reported the association between flavonoid intake, cardiovascular mortality and ischaemic stroke among a group of participants in the Kuopio Ischaemic Heart Disease Risk Factor Study.

Following the publication of the landmark trial of Clark et al. in 1996 that appeared to show that Se could reduce the risk of cancer, awareness of the importance of Se to human health has markedly increased. As a result, there is now much more aggressive marketing of Se supplements and functional foods, even in situations where additional consumption of Se is inappropriate. The present review addresses how Se gets into the food chain, the wide variability in Se content of foods and the very different levels of intake between countries and regions. Though it is clear that there are adverse consequences for health of both deficient and excessive intake, health effects at intermediate levels of intake are less certain. Thus it is difficult to define optimal intake which depends on a large number of factors, such as which functions of Se are most relevant to a particular disease state, which species of Se is most prominent in the Se source, which health condition is being considered, the adequacy or otherwise of intake of other nutrients, the presence of additional stressors, and lastly whether the ability to make selenoproteins may be compromised. These complexities need to be understood, particularly by policy makers, in order to make informed judgments. Potential solutions for increasing Se intake, where required, include agronomic biofortification and genetic biofortification or, for individuals, increased intake of naturally Se-rich foods, functional foods or supplements. The difficulties of balancing the risks and benefits in relation to Se intake are highlighted.

It has recently been reported that the increased prevalence in childhood allergy may be linked to deviations in fetal immune development. One reason may be impaired nutrient supply. Hence, a well-differentiated placenta together with an optimal fetal nutrition via the mother are important prerequisites for the establishment of a functional immune system with normal immune responses. Fatty acids and their derivatives can influence both the early immune development and immune maturation by regulating numerous metabolic processes and the gene expression of important proteins such as enzymes and cytokines. The present review summarises the impact of nutritional fatty acids on the development of the immune system as well as the fetal development. It describes the mechanisms of action of PUFA, trans fatty acids and conjugated linoleic acids in programming the fetus with regard to its risk of acquiring atopic diseases in childhood.

Fructose consumption in the USA has increased over the past three decades. During this time, obesity, insulin resistance and the metabolic syndrome have also increased in prevalence. While diets high in fructose have been shown to promote insulin resistance and increase TAG concentrations in animals, there are insufficient data available regarding the long-term metabolic effects of fructose consumption in humans. The objective of the present study was to investigate the metabolic effects of 10-week consumption of fructose-sweetened beverages in human subjects under energy-balanced conditions in a controlled research setting. Following a 4-week weight-maintaining complex carbohydrate diet, seven overweight or obese (BMI 26·8–33·3 kg/m2) postmenopausal women were fed an isoenergetic intervention diet, which included a fructose-sweetened beverage with each meal, for 10 weeks. The intervention diet provided 15 % of energy from protein, 30 % from fat and 55 % from carbohydrate (30 % complex carbohydrate, 25 % fructose). Fasting and postprandial glucose, insulin, TAG and apoB concentrations were measured. Fructose consumption increased fasting glucose concentrations and decreased meal-associated glucose and insulin responses (P = 0·0002, P = 0·007 and P = 0·013, respectively). Moreover, after 10 weeks of fructose consumption, 14 h postprandial TAG profiles were significantly increased, with the area under the curve at 10 weeks being 141 % higher than at baseline (P = 0·04). Fructose also increased fasting apoB concentrations by 19 % (P = 0·043 v. baseline). In summary, consumption of fructose-sweetened beverages increased postprandial TAG and fasting apoB concentrations, and the present results suggest that long-term consumption of diets high in fructose could lead to an increased risk of CVD.

We have previously reported the anticarcinogenic effects of an olive fruit extract composed of pentacyclic triterpenes, the main components of which are maslinic acid (73·25 %) and oleanolic acid (25·75 %). Here we examined the effects of the individual components on proliferation, necrosis and apoptosis rates by fluorescence-based techniques in human HT-29 colon cancer cells. Oleanolic acid showed moderate antiproliferative activity, with an ec50 of 160·6 (se 10·6) μmol/l, and moderate cytotoxicity at high concentrations ( ≥ 250 μmol/l). On the other hand, maslinic acid inhibited cell growth with an ec50 of 101·2 (se 7·8) μmol/l, without necrotic effects. Oleanolic acid, which lacks a hydroxyl group at the carbon 2 position, failed to activate caspase-3 as a prime apoptosis protease. In contrast, maslinic acid increased caspase-3-like activity at 10, 25 and 50 μmol/l by 3-, 3·5- and 5-fold over control cells, respectively. The detection of ROS in the mitochondria, which serve as pro-apoptotic signal, evidenced the different bioactivity of the two triterpenes. Confocal microscopy analysis revealed that maslinic acid generated superoxide anions while oleanolic acid-treated cells did not differ from the control. Completion of apoptosis by maslinic acid was confirmed microscopically by the increase in plasma membrane permeability, and detection of DNA fragmentation. In conclusion, the anticancer activity observed for olive fruit extracts seems to originate from maslinic acid but not from oleanolic acid. Maslinic acid therefore is a promising new compound for the chemoprevention of colon cancers.

In contrast to some extensively examined food mutagens, for example, aflatoxins, N-nitrosamines and heterocyclic amines, some other food contaminants, in particular polycyclic aromatic hydrocarbons (PAH) and other aromatic compounds, have received less attention. Therefore, exploring the relationships between dietary habits and the levels of biomarkers related to exposure to aromatic compounds is highly relevant. We have investigated in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort the association between dietary items (food groups and nutrients) and aromatic DNA adducts and 4-aminobiphenyl-Hb adducts. Both types of adducts are biomarkers of carcinogen exposure and possibly of cancer risk, and were measured, respectively, in leucocytes and erythrocytes of 1086 (DNA adducts) and 190 (Hb adducts) non-smokers. An inverse, statistically significant, association has been found between DNA adduct levels and dietary fibre intake (P = 0·02), vitamin E (P = 0·04) and alcohol (P = 0·03) but not with other nutrients or food groups. Also, an inverse association between fibre and fruit intake, and BMI and 4-aminobiphenyl-Hb adducts (P = 0·03, 0·04, and 0·03 respectively) was observed. After multivariate regression analysis these inverse correlations remained statistically significant, except for the correlation adducts v. fruit intake. The present study suggests that fibre intake in the usual range can modify the level of DNA or Hb aromatic adducts, but such role seems to be quantitatively modest. Fibres could reduce the formation of DNA adducts in different manners, by diluting potential food mutagens and carcinogens in the gastrointestinal tract, by speeding their transit through the colon and by binding carcinogenic substances.

We have previously reported that dietary fructose rapidly induces jejunal sucrase–isomaltase (SI) gene expression in rats. In this study, we confirmed in mice that SI mRNA was induced 6 h after force-feeding fructose, but not glucose. Using the chromatin immunoprecipitation assay, we revealed that histones H3 and H4 on the promoter/enhancer regions of the SI gene in mice given fructose were highly acetylated, compared with those given glucose or water. These results suggest that acute induction of SI gene expression by dietary fructose is associated with acetylation of histones H3 and H4 on the SI gene.

The loss of weight was analysed in a group of sixty overweight/obese women of childbearing age (20–35 years) according to their initial vitamin D status. Subjects were randomly assigned to one of two slightly hypocaloric diets: Diet V, in which the consumption of vegetables was increased, or Diet C, in which the relative consumption of cereals (especially breakfast cereals) was increased. Dietetic, anthropometric and biochemical data were collected at the start of the study and again at 2 weeks after dividing the women into groups depending on their having an initial serum 25-hydroxyvitamin D (25(OH)D) concentration of < 50 nmol/l (LD) or ≥ 50 nmol/l (HD). Dietary intervention led to a reduction in energy intake, body weight and BMI in all groups. The HD women showed greater body fat losses during the study than the LD women (1·7 (sd 1·8) kg compared to 0·5 (sd 0·8) kg). A better vitamin D status therefore aided the loss of body fat over the experimental period (OR 0·462; CI 0·271, 0·785; P < 0·001). However, when the dietary groups were analysed separately, this effect was only seen in the C subjects (OR 0·300; CI 0·121, 0·748; P < 0·001). The present results suggest that women with a better vitamin D status respond more positively to hypocaloric diets and lose more body fat; this was especially clear among the C subjects who had a greater vitamin D supply during the experimental period.

We aimed to synthesise evidence to assess the effect and safety of NaFeEDTA on Hb and serum ferritin in Fe-deficient populations. We performed a systematic review, identifying potential studies by searching the electronic databases of Medline, Cochrane Library, Embase, WHO Library and China National Knowledge Infrastructure. We also hand-searched relevant conference proceedings and reference lists. Finally, we contacted experts in the field. The selection criteria included randomised or quasi-randomised controlled trials of NaFeEDTA compared with placebo. Hb, serum ferritin and adverse effects were outcomes of interest. Inclusion decisions, quality assessment and data extraction were performed by two reviewers independently. Seven studies met the inclusion criteria. All included studies assessed the effect of NaFeEDTA on Hb concentration, four studies assessed the effect on serum ferritin concentration, and one study on serum Zn concentration. After the intervention, Hb concentration and serum ferritin concentration were both higher in the NaFeEDTA group compared with the control group. For Hb, data from six studies could be pooled and the pooled estimate (weighted mean difference) was 8·56 (95 % CI 2·21, 14·90) g/l (P = 0·008). For serum ferritin, data from four studies could be pooled and the pooled difference was 1·58 (95 % CI 1·20, 2·09) μg/l (P < 0·001). Subgroup analysis indicated that a lower baseline Hb level was associated with a greater increase in Hb concentration. No significant difference in serum Zn concentration was found. We concluded that NaFeEDTA increased both Hb concentration and serum ferritin concentration substantially in Fe-deficient populations, and could be an effective Fe preparation to combat Fe deficiency.

Epoxyxanthophylls (epoxide-containing xanthophylls), a group of carotenoids, are ubiquitously distributed in edible plants. Among them, neoxanthin in green leafy vegetables and fucoxanthin in brown algae have been reported to exhibit an antiproliferative effect on several human cancer cells in vitro. However, there is little information about the intestinal absorption and metabolic fate of dietary epoxyxanthophylls in humans. To estimate the intestinal absorption of neoxanthin and fucoxanthin in humans, we evaluated the plasma epoxyxanthophyll concentrations before and after 1-week dietary interventions with spinach (Spinacia oleracea) and wakame (Undaria pinnatifida). The epoxyxanthophylls and their metabolites in the plasma extracts were determined by HPLC after partial purification and concentration with solid-phase extraction cartridges. Even after 1 week of spinach intake (3·0 mg neoxanthin/d), the plasma concentrations of neoxanthin and its metabolites (neochrome stereoisomers) remained very low (about 1 nmol/l), whereas those of β-carotene and lutein were markedly increased. Similarly, the plasma concentration of fucoxanthinol, a gastrointestinal metabolite of fucoxanthin, was < 1 nmol/l after 1 week of wakame intake (6·1 mg fucoxanthin/d). These results indicated that the plasma response to dietary epoxyxanthophylls was very low in humans even after 1-week intake of epoxyxanthophyll-rich diets.

Reducing the reliance on fishery by-products as amino acid and fatty acid sources in feeds for farmed fish is a major objective today. We evaluated the effect of dietary fish oil or dietary fishmeal replacement by vegetable oils and plant proteins respectively through analysis of hepatic transcriptomes in rainbow trout (Oncorhynchus mykiss). Fish were fed right from first feeding with diets based on plant by-products before being killed. We analysed the hepatic gene profile using trout cDNA microarrays (9K). Our data showed that seventy-one and seventy-five genes were affected after fish oil and fishmeal replacement respectively. The major part of modified gene expression coding for proteins of the metabolic pathways was as follows: (i) a lower level of expression for genes of energy metabolism found in fish after fishmeal and fish oil replacement; (ii) a lower level of gene expression for fatty acid metabolism (biosynthesis) in fish fed with vegetable oils; (iii) a differential expression of actors of detoxification metabolism in trout fed with vegetable oils; (iv) a lower level of expression of genes involved in protein metabolism in fish fed with plant proteins. Overall, our data suggest that dietary fish oil replacement is linked to a decreased capacity of fatty acid biosynthesis (fatty acid synthase) and variation of detoxification metabolism (cytochrome P450s) whereas dietary fishmeal replacement may depress protein metabolism in the liver as reflected by glutamine synthetase.

In the present study, eighty-four breast cancer patients were randomized to receive a daily supplement of 100 mg co-enzyme Q10, 10 mg riboflavin and 50 mg niacin (CoRN), one dosage per d along with 10 mg tamoxifen twice per d. A significant increase in poly(ADP-ribose) polymerase levels and disappearance of RASSF1A DNA methylation patterns were found in patients treated with supplement therapy along with tamoxifen compared to untreated breast cancer patients and tamoxifen alone-treated patients. An increase in DNA repair enzymes and disappearance of DNA methylation patterns attributes to reduction in tumour burden and may suggest good prognosis and efficacy of the treatment.

The present study evaluates for the first time in dogs, the kinetics of green tea catechins and their metabolic forms in plasma and urine. Ten beagles were administered 173 mg (12·35 mg/kg body weight) of catechins as a green tea extract, in capsules. Blood samples were collected during 24 h after intake and urine samples were collected during the following periods of time: 0–2, 2–6, 6–8 and 8–24 h. Two catechins with a galloyl moiety and three conjugated metabolites were detected in plasma. Most of the detected forms in plasma reached their maximum plasma concentration (Cmax) at around 1 h. Median Cmax for ( − )-epigallocatechin-3-gallate (EGCG), ( − )-epicatechin-3-gallate (ECG), ( − )-epigallocatechin glucuronide (EGC-glucuronide), ( − )-epicatechin glucuronide (EC-glucuronide), ( − )-epicatechin sulphate (EC-sulphate) were 0·3 (range 0·1–1·9), 0·1 (range 0–0·4), 0·8 (range 0·2–3·9), 0·2 (range 0·1–1·7) and 1 (range 0·3–3·4) μmol/l, respectively. The areas under the plasma concentration v. time curves (AUC0 → 24) were 427 (range 102–1185) μmol/l × min for EGC-glucuronide, 112 (range 53–919) μmol/l × min for EC-sulphate, 71 (range 26–306) μmol/l × min for EGCG, 40 (range 12–258) μmol/l × min for EC-glucuronide and 14 (range 0·1–124) μmol/l × min for ECG. The values of mean residence time (MRT0 → 24) were 5 (range 2–16), 2 (range 1–11), 10 (range 2–13), 3 (range 2–16) and 2·4 (range 1–18) h for EGCG, ECG, EGC-glucuronide, EC-glucuronide and EC-sulphate, respectively. In urine, catechins were present as conjugated forms, suggesting bile excretion of EGCG and ECG. Green tea catechins are absorbed following an oral administration and EGC-glucuronide is the metabolic form that remains in the organism for a longer period of time, suggesting that this compound could suffer an enterohepatic cycle.

The molecular basis of the positive association between apoE4 genotype and CVD remains unclear. There is direct in vitro evidence indicating that apoE4 is a poorer antioxidant relative to the apoE3 isoform, with some indirect in vivo evidence also available. Therefore it was hypothesised that apoE4 carriers may benefit from α-tocopherol (α-Toc) supplementation. Targeted replacement mice expressing the human apoE3 and apoE4 were fed with a diet poor (0 mg/kg diet) or rich (200 mg/kg diet) in α-Toc for 12 weeks. Neither apoE genotype nor dietary α-Toc exerted any effects on the antioxidant defence system, including glutathione, catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase activities. In addition, no differences were observed in mitogen-induced lymphocyte proliferation. α-Toc concentrations were modestly higher in plasma and lower in tissues of apoE4 compared with apoE3 mice, with the greatest differences evident in the lung, suggesting that an apoE4 genotype may reduce α-Toc delivery to tissues. A tendency towards increased plasma F2-isoprostanes in apoE4 mice was observed, while liver thiobarbituric acid-reactive substances did not differ between apoE3 and apoE4 mice. In addition, C-reactive protein (CRP) concentrations were reduced in apoE4 mice indicating that this positive effect on CRP may in part negate the increased CVD risk associated with an apoE4 genotype.

As part of the rapid socio-cultural transition observed in Arctic populations, the Inuit diet is changing. We present original data derived from the baseline Inuit Health in Transition cohort study regarding biological levels of n-3 fatty acids and trans-fatty acids (TFA), lipids with opposite health effects found respectively in traditional marine diets and recently introduced low-quality imported foods. A total of 524 Inuit from the Disko Bay area (Greenland) and 888 Inuit from the fourteen communities of Northern Québec (Nunavik) participated in the study. We measured the fatty acid profile of erythrocyte (RBC) membrane phospholipids (PL) as a surrogate for individual intakes. Moreover, the contribution of store-bought foods to energy intakes was assessed through dietary questionnaires. Our results show that while n-3 fatty acid levels were slightly lower in Nunavik (9·4 % of RBC membrane PL) than in Greenland (12·1 %), TFA levels were on average nearly thrice as high in Nunavik Inuit (1·20 %) as they were in Greenlanders (0·43 %). Moreover, younger Nunavik Inuit accumulated higher intakes of TFA and lower intakes of n-3 fatty acids. Finally, the average proportion of energy derived from store-bought foods was high in both groups (77·5 % and 83·5 %), especially in youth. Our results call for action to rehabilitate and recover access to country foods and point to the importance for Nunavik and the entire circumpolar world to follow the example of Denmark and Greenland, which imposed a maximum content of 2 g/100 g fat on industrially produced trans-fats in 2003.

So far, a protective influence of phytosterols on the human organism and atherogenesis has been suggested. Most studies have concentrated on the cytotoxic efficacy of phytosterols on cancer cells. However, there are only a few reports showing their influence on normal cells. The aim of the present study was to determine whether dietary plant sterols and their thermal processing products could influence the viability of normal, abdominal endothelial cells that play a crucial role in atherogenesis. Thus, we studied the effect of rapeseed oil-extract components, β-sitosterol, cholesterol and their epoxy-derivatives, 5α,6α-epoxy-β-sitosterol and 5α,6α-epoxycholesterol, on the proliferation and viability of human abdominal aorta endothelial cells HAAE-2 in vitro. We showed strong cytotoxic properties of β-sitosterol in HAAE-2 cells (half maximal inhibitory concentration (IC50) = 1·99 (sem 0·56) μm) and, interestingly, a weaker cytotoxic effect of 5α,6α-epoxy-β-sitosterol (IC50>200 μm). Moreover, we observed a significantly stronger cytotoxic activity of β-sitosterol than cholesterol (IC50 = 8·99 (sem 2·74) μm). We also revealed that β-sitosterol as well as cholesterol caused apoptosis, inducing caspase-3 activity in the cells (60 % increase compared with control cells) that corresponded to the DNA fragmentation analysis in a terminal uridine deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling (TUNEL) study. Although absorption of plant sterols is low compared with cholesterol, they can still influence other physiological functions. Since they effectively reduce serum LDL-cholesterol and atherosclerotic risk but also decrease the viability of cancer cells as well as normal cells in a time- and dose-dependent manner in vitro, their influence on other metabolic processes remains to be elucidated.

The biological activities of a protein isolate from lupin (Lupinus albus) were studied in a rabbit model of atherosclerosis. Focal plaque development was induced at both common carotid arteries by perivascular injury. After surgery, animals were fed three different diets for 90 d, all with 1 % cholesterol, 15 % SFA and 20 % protein; the protein source was casein (CAS), lupin proteins (LUP) or 50 % CAS+50 % LUP (CAS+LUP). Lower cholesterolaemia was detected in the LUP v. the CAS group at 60 and 90 d of treatment ( − 40·3 and − 33·5 %, respectively; P < 0·05). Cryosection analyses of the carotids indicated a significant reduction in focal lesion progression in the LUP v. the CAS group ( − 37·4 %; P < 0·05). In summary, in a rabbit model of atherosclerosis, a protein isolate from L. albus reduced cholesterolaemia and exerted a remarkable protective activity against atherosclerosis progression.

This study tested the hypothesis that protein source is a factor determining the impact of the diet on lipid metabolism in hamsters. Twenty-eight hamsters of similar body weight were assigned for a period of 8 weeks to one of the following four diets (seven per group) containing either 20 % (w/w) casein (CAS), beef protein (BF), wheat gluten (WG) or soya protein (SOY). The fat composition of the diet was the same (15·5 % w/w) in all groups and provided SFA, MUFA and PUFA representative of the average Canadian diet. After an overnight fast, blood and liver were collected for the measurement of serum lipids, fatty acid composition of liver phospholipids and mRNA levels of selected genes involved in lipid metabolism. WG resulted in lower total cholesterol, HDL-cholesterol and non-HDL-cholesterol but, along with SOY, in higher mRNA levels of cholesterol 7 α-hydroxylase and LDL receptor. Furthermore, both WG and SOY resulted in lower 18 : 3n-3, 20 : 4n-6, total n-6 PUFA, 18 : 1n-9 and total MUFA, but higher 22 : 6n-3, total n-3 PUFA, 22 : 6n-3/18 : 3n-3 and 22 : 5n-3/18 : 3n-3 ratios in liver phospholipids, and higher hepatic Δ6-desaturase mRNA levels. These results show that the impact of dietary protein on lipid metabolism is source-dependent and associated with changes in mRNA abundances of key hepatic enzymes and receptors.

We investigated the effects of the flavonols kaempferol and quercetin on the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), endothelial cell selectin (E-selectin), inducible NO synthase (iNOS) and cyclo-oxygenase-2 (COX-2), and on the activation of the signalling molecules NF-κB and activator protein-1 (AP-1), induced by a cytokine mixture in cultured human umbilical vein endothelial cells. Inhibition of reactive oxygen and nitrogen species generation did not differ among both flavonols at 1 μmol/l but was significantly stronger for kaempferol at 5–50 μmol/l. Supplementation with increasing concentrations of kaempferol substantially attenuated the increase induced by the cytokine mixture in VCAM-1 (10–50 μmol/l), ICAM-1 (50 μmol/l) and E-selectin (5–50 μmol/l) expression. A significantly inhibitory effect of quercetin on VCAM-1 (10–50 μmol/l), ICAM-1 (50 μmol/l) and E-selectin (50 μmol/l) expression was also observed. Expression of adhesion molecules was always more strongly inhibited in kaempferol-treated than in quercetin-treated cells. The inhibitory effect on iNOS and COX-2 protein level was stronger for quercetin at 5–50 μmol/l. The effect of kaempferol on NF-κB and AP-1 binding activity was weaker at high concentrations (50 μmol/l) as compared with quercetin. The present study indicates that differences exist in the modulation of pro-inflammatory genes and in the blockade of NF-κB and AP-1 by kaempferol and quercetin. The minor structural differences between both flavonols determine differences in their anti-inflammatory properties and in their efficiency in inhibiting signalling molecules.