Eritadenine-induced alterations of plasma lipoprotein lipid concentrations and phosphatidylcholine molecular species profile in rats fed cholesterol-free and cholesterol-enriched diets

Enhancing Eritadenine Production in Submerged Cultures of Shiitake (Lentinula edodes Berk. Pegler) Using Blue LED Light and Activated Charcoal. Revealing Eritadenine's Novel In Vitro Bioherbicidal Activity Against Chrysanthemum morifolium

Eritadenine from shiitake mushroom is a secondary metabolite with hypocholesterolemic, hypotensive and antiparasitic properties, thus promising for pharmaceutical and agricultural applications. Eritadenine is obtained from submerged mycelial cultures of shiitake, but the actual yields remain unsatisfactory to explore potential applications or industrial-scale production. In this study, green and blue LED lights were tested to increase yields of eritadenine in submerged cultures of shiitake. Notably, blue LEDs increased yields by 13-14 times, reaching 165.7 mg/L, compared to darkness (11.2 mg/L) and green light (12.1 mg/L) (p < 0.05, Tukey test). Nitrogen sources yeast extract (YE) and peptone (at 2 g/L) increased eritadenine production. YE promoted 22.6 mg/L, while peptone 18.3 mg/L. The recovery of eritadenine was evaluated using amberlite and activated charcoal (AC) adsorption isotherms. AC demonstrated the highest adsorption rate, with 75 mg of eritadenine per gram of AC, according to the Freundlich isotherm. The desorption rate reached 93.95% at pH 10. The extract obtained from submerged cultures had eritadenine content of 63.31%, corresponding to 87.86% of recovery, according to HPLC analysis. Furthermore, the novel bioherbicidal potential of eritadenine was tested on in vitro Chrysanthemum morifolium plants. The cultures extract containing eritadenine had a detrimental impact on plant development, generating mortality of 100% at 3%, 0.5%, and 0.25%. Moreover, pure eritadenine exhibited a phytotoxic effect similar than glyphosate on leaves, stems and roots. These findings highlight the significant bioherbicidal properties of eritadenine. Further studies are needed to understand the biosynthetic pathway of eritadenine and its bioherbicidal properties on weeds and illicit crops.

Antiangiogenic potential of Lepista nuda extract suppressing MAPK/p38 signaling-mediated developmental angiogenesis in zebrafish and HUVECs

The medicinal properties of natural/edible plant products and their use are popular in traditional practice owing to their nutritional contents with little to no side effects. Lepista nuda (L. nuda), an edible mushroom (Clitocybe nuda, commonly known as blewit), has attracted researchers to evaluate its contents and the mechanism of its activities. In the current study, we focused on evaluating the antiangiogenic effects of L. nuda water extract on zebrafish development and in vitro human umbilical vein endothelial cell (HUVEC) tube formation. Bioactive components such as ergothioneine, eritadenine, and adenosine were identified and quantified by HPLC analysis. The L. nuda extract showed antiangiogenic properties and inhibited intersegmental vessel (ISV), caudal vein plexus (CVP), hyaloid vessel (HV), and subintestinal vessel (SIV) development in Tg (fli1: EGFP) zebrafish embryos. The expression of angiogenesis-related genes (vegfaa, kdrl, vegfba, flt1, kdr) was affected following L. nuda extract treatment. L. nuda extract attenuated in vitro HUVEC tube formation, migration, and invasion. Furthermore, inhibition of MAPK/p38 signaling and depletion of proangiogenic genes, including growth factors (fgf, ang2, and vegfa); primary and accessory receptors (tie2, vegfr2, and eng); MMPs (mmp1 and mmp2); and cytokines (il-1α, il-1β, il-6, and tnf-α) was observed in HUVECs following L. nuda treatment. An in vivo zebrafish xenograft assay showed that L. nuda extract inhibited HuCCT1 cell-induced SIV sprouting in HuCCT1-injected embryos. Collectively, the results suggest that L. nuda could be a potential inhibitor of angiogenesis limiting cancer progression.

Increasing the production of the bioactive compounds in medicinal mushrooms: an omics perspective

Macroscopic fungi, mainly higher basidiomycetes and some ascomycetes, are considered medicinal mushrooms and have long been used in different areas due to their pharmaceutically/nutritionally valuable bioactive compounds. However, the low production of these bioactive metabolites considerably limits the utilization of medicinal mushrooms both in commerce and clinical trials. As a result, many attempts, ranging from conventional methods to novel approaches, have been made to improve their production. The novel strategies include conducting omics investigations, constructing genome-scale metabolic models, and metabolic engineering. So far, genomics and the combined use of different omics studies are the most utilized omics analyses in medicinal mushroom research (both with 31% contribution), while metabolomics (with 4% contribution) is the least. This article is the first attempt for reviewing omics investigations in medicinal mushrooms with the ultimate aim of bioactive compound overproduction. In this regard, the role of these studies and systems biology in elucidating biosynthetic pathways of bioactive compounds and their contribution to metabolic engineering will be highlighted. Also, limitations of omics investigations and strategies for overcoming them will be provided in order to facilitate the overproduction of valuable bioactive metabolites in these valuable organisms.

Identification of matB used as an endogenous reference gene for the qualitative and real-time quantitative polymerase chain reaction detection of Lentinus edodes

Lentinus edodes is a fungus with rich nutritional value and good medicinal value and has accordingly become a substitute for other expensive wild edible mushrooms. In this study, for the first time, the matB gene was selected as an endogenous reference gene of L. edodes and identified as the species-specific gene. The matB genes of L. edodes and 18 non-L. edodes species were determined by qualitative polymerase chain reaction (PCR), but no amplification was found in non-L. edodes species. In SYBR Green quantitative PCR analysis, the detection limit was as low as 16 pg/µl of DNA template. All of these experiments indicated that the matB gene is an ideal reference gene and can detect L. edodes material through qualitative and quantitative PCR assays. It also provides a convenient and accurate approach for the detection of L. edodes products and the adulteration in wild edible mushroom products.

Effect of traditional and modern culinary processing, bioaccessibility, biosafety and bioavailability of eritadenine, a hypocholesterolemic compound from edible mushrooms

Eritadenine is a hypocholesterolemic compound that is found in several mushroom species such as Lentinula edodes, Marasmius oreades, and Amanita caesarea (1.4, 0.7 and 0.6 mg per g dry weight, respectively). It was synthesized during all developmental stages, being present in higher concentrations in the skin of shiitake fruiting bodies. When subjected to traditional cooking, grilling followed by frying were more adequate methodologies than boiling or microwaving to maintain its levels. Modern culinary processes such as texturization (with agar-agar) and spherification (with alginate) also interfered with its release. Grilling and gelling using gelatin enhanced eritadenine's bioaccessibility in an in vitro digestion model. An animal model (where male and female rats were administered 21 and 10 mg per kg animal per day of eritadenine) indicated that intake of the compound was safe under these concentrations; it reached the liver and reduced the atherogenic index (TC/HDL) in rat sera. Thus, it might be used to design a functional food.

Extraction of bioactive compounds against cardiovascular diseases from Lentinula edodes using a sequential extraction method

Three extraction methods were sequentially combined to obtain fractions from Lentinula edodes (shiitake mushrooms) containing bioactive compounds against cardiovascular diseases (CVDs). Fruiting bodies were first extracted with plain water, obtained residue was then submitted to supercritical fluid extraction (SFE) and remaining residue submitted to hot water extraction. Sequential design allowed reutilization of the nonextracted material as raw material for the successive extractions increasing extraction yields and separating interesting compounds. Obtained fractions contained different amounts of ß-glucans, chitins, eritadenine, lenthionine, ergosterol, proteins/peptides and phenolic compounds conferring them different bioactivities. Water soluble fractions showed high antioxidant activities (ABTS^+• and DPPH^• scavenging capacity and reducing power), they were also able to inhibit one of the main enzymes involved in hypertension (angiotensin-I converting enzyme) and the key enzyme of cholesterol metabolism (3-hydroxy-3-methylglutaryl coenzyme A reductase). The latter inhibitory activity was also noticed in SFE extracts although ergosterol and other lipid-like molecules were isolated. Dietary fibers were separated in the third extraction. Therefore, with this sequential extraction procedure bioactive compounds against CVDs can be selectively separated from a single batch of shiitake powder. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:746-755, 2018.

Hyperlipidemic Inhibitory Effects of Phellinus pini in Rats Fed with a High Fat and Cholesterol Diet

This study evaluated the in vitro and in vivo hypolipidemic effects of the medicinal mushroom Phellinus pini. The methanol extract (ME) of the fruiting body of Ph. pini was active against pancreatic lipase and cholesterol esterase with 99.14% and 67.23% inhibited activity at 1.0 mg/mL, respectively. It also inhibited 81.81% and 55.33% of α-glucosidase and α-amylase activities, respectively, at 2.0 mg/mL. Hyperlipidemia as induced by feeding rats with a high fat and cholesterol diet (HFC). HFC supplemented with a 5% fruiting body powder of Ph. pini (HFC + PhP) significantly reduced plasma total cholesterol, low-density lipoprotein cholesterol, and triglycerides in rats compared with HFC. The reduced levels were comparable to rats fed the normal control diet (NC). The atherogenic index of HFC + PhP rats was significantly lower than that of the HFC rats. The excretion of fecal total lipid and cholesterol in the HFC + PhP rats was significantly higher than those in the NC and HFC rats. Histopathological examinations demonstrated scant deposition of lipids in the liver of rats fed HFC + PhP. The dietary supplementation with the fruiting body powder provided natural plasma lipid and glucose lowering effects in experimental rats without adverse effects on the plasma biochemical parameters and liver function related enzyme activities. Therefore, the hypolipidemic effects of Ph. pini may be due to the inhibitory effects on pancreatic lipase, cholesterol esterase, α-glucosidase, and α-amylase, and excretion of excess lipids and cholesterol in the feces.

Diets Containing Shiitake Mushroom Reduce Serum Lipids and Serum Lipophilic Antioxidant Capacity in Rats

BACKGROUND

We previously reported that dietary intake of shiitake mushroom (SM; Lentinus edodes) decreased serum concentrations of polar lipids in male rats.

OBJECTIVE

This study evaluated the dietary effects of SM on serum cholesterol-related and serum antioxidant indexes in rats of both sexes.

METHODS

Sprague-Dawley rats [38 dams and their offspring (20 males and 20 females/diet)] were fed diets containing 0 (control), 1%, 4%, or 10% (wt:wt) SM powder from gestation day 4 through to postnatal day (PND) 126. Biochemical indexes were monitored during the midgrowth phase (PNDs 50-66).

RESULTS

The food consumption by offspring fed the control diet and diets supplemented with SM was not different when measured on PND 65. However, the 4% and 10% SM diets resulted in male rats with 7% lower body weights than those of the other 2 groups on PND 66. SM consumption dose-dependently decreased the concentrations of lipidemia-related factors in sera, irrespective of sex. At PND 50, serum concentrations of total cholesterol, HDL cholesterol, and non-HDL cholesterol in SM-fed male and female rats were generally lower (3-27%) than those in the corresponding control groups. Consumption of the 10% SM diet resulted in significantly decreased (55%) serum triglyceride concentrations relative to the control groups for both sexes. The 10% SM diet elicited a 62% reduction of serum leptin concentrations in females but not in males, and this same diet increased serum insulin (137%) and decreased serum glucose (15%) in males compared with controls. Serum lipophilic antioxidant capacity in males and females fed SM diets was generally lower (31-86%) than that in the control groups.

CONCLUSION

SM decreased the concentrations of lipidemia-related factors in rat sera irrespective of sex. The SM-elicited reduction of lipophilic antioxidant capacity irrespective of sex may reflect a lower pro-oxidative state and, hence, improved metabolic profile.

Mushroom intake and risk of epithelial ovarian cancer in southern Chinese women

OBJECTIVE

This study aimed to investigate the association between mushroom consumption and risk of epithelial ovarian cancer in southern Chinese women.

METHODS

A hospital-based case-control study was undertaken in Guangzhou, Guangdong Province, from 2006 to 2008. Participants were 500 incident patients with epithelial ovarian cancer and 500 controls, with a mean (SD) age of 59 (6) years. Information on habitual mushroom consumption was obtained by face-to-face interview using a validated and reliable food frequency questionnaire. Unconditional logistic regression analyses were performed to assess the association between mushroom intake and the ovarian cancer risk.

RESULTS

The patients with ovarian cancer consumed less mushrooms (mean [SD], 28.48 [37.45] g/d) than did controls (mean [SD], 30.75 [41.85] g/d). Apparent reductions in cancer risk were found at high levels of intake, especially for the common white button mushroom with adjusted odds ratios 0.68 (95% confidence interval, 0.52-0.89) for women consuming more than 2 g per day relative to those who consume less than that (P = 0.005). Decreases in risk at high levels of intake were also observed for serous and mucinous subtypes of epithelial ovarian tumors.

CONCLUSIONS

Intake of mushrooms, particularly white button mushroom, seemed to be inversely associated with the incidence of epithelial ovarian cancer in southern Chinese women.

A high-dose Shiitake mushroom increases hepatic accumulation of triacylglycerol in rats fed a high-fat diet: underlying mechanism

Shiitake mushroom have been shown to have health benefits including lowering plasma lipids and preventing body weight gain. However, their underlying mechanisms are largely unknown. The study aim was to assess the potential underlying mechanism of Shiitake mushrooms in lowering plasma triacylglycerol (TAG) in rats fed a high fat diet (HFD). Forty Wistar rats were divided into control group were given HFD and treatment group were fed HFD, enriched with Shiitake mushroom powder at a low dose (LD-M): 0.7%, medium dose (MD-M): 2%, or high dose (HD-M): 6% (wt:wt) for six weeks. Diets were isocaloric containing ~50% energy from fat. After six weeks' dietary intervention, the rats were sacrificed, and blood and tissue samples were collected. The HD-M group showed a significantly higher ratio of liver weight to 100 g body weight (p < 0.05), a more severe hepatic steatosis marker, such as hepatocyte ballooning (p < 0.0001), and more liver triacylglycerol content than LD-M and MD-M (p < 0.05). HD-M also showed a significantly decreased ratio of phosphatidylcholine (PC) to phosphatidylethanolamine (PE) compared to HFD (p < 0.05), however, there were no differences compared to HD-M and MD-M. Our results also showed a positive association between the dosage, liver TAG, and liver ballooning histology. A negative association was found between the mushroom dosage and the ratio of liver PC to PE. This study showed the mechanism of how high-dose Shiitake mushroom (HD-M) prevents obesity by increasing TAG accumulation in the liver, rather than adipose tissue.

Hypolipidemic effect of the edible mushroom Agaricus blazei in rats subjected to a hypercholesterolemic diet

The effects of Agaricus blazei intake on the lipid profile of animals fed a hypercholesterolemic diet were evaluated. Thirty-two female Fisher rats were divided into four groups and given the standard AIN-93 M diet (C), this diet + 1 % A. blazei (CAb), a hypercholesterolemic diet with 25 % soybean oil and 1 % cholesterol (H) or this diet + 1 % A. blazei (HAb) for 6 weeks. Food intake, weight gain, liver and serum lipid profiles, activity of aminotransferases [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)], and creatinine and urea levels as well as abdominal fat weight were measured. Histological analysis of kidney and liver tissue was also performed. The HAb group had a higher food intake, but a lower weight gain as compared to group H. This resulted in a significant decrease in abdominal fat weight, to values close to those of groups C and CAb. Supplementing the hypercholesterolemic diet with A. blazei promoted a significant reduction in total and non-HDL cholesterol, as well as in the atherogenic index, as compared to group H, and this effect was more pronounced in the serum. There was no hepatotoxic effect caused by the supplementation of the diets with the mushroom. We conclude that in our experimental model and in the concentration used, A. blazei was effective in improving the lipid profile of the animals.

Lentinus edodes promotes fat removal in hypercholesterolemic mice

Lentinus (L.) edodes (shiitake mushroom) is used as a traditional medicine in Asia. One of the components of L. edodes, eritadenine (an adenosine analog alkaloid), has been shown to reduce cholesterol levels. The hypocholesterolemic action of eritadenine appears to be achieved through the modification of hepatic phospholipid metabolism. In the present study, the effects of L. edodes in a mouse model of hypercholesterolemia were investigated. Hypercholesterolemia was induced by the consumption of a high-fat diet (HFD). The animals were divided into six groups, which were fed a normal diet, HFD alone, HFD containing eritadenine [10 mg/kg of body weight (BW)] or HFD with 5, 10 or 20% L. edodes, respectively, for 4 weeks (from 5 to 9 weeks of age). The mice in the six groups had similar BW gains. Total serum cholesterol (T-CHO), low-density lipoprotein (LDL) and triglyceride (TG) levels were increased in the HFD-fed group compared with those in the normal diet group. However, the levels of high-density lipoprotein (HDL) were not significantly altered. In mice treated with L. edodes (5, 10 or 20%), the T-CHO, LDL and TG serum levels were reduced in a dose-dependent manner. The mRNA expression of cholesterol 7-α-hydroxylase 1 (CYP7A1) was decreased in hypercholesterolemic mice and increased by eritadenine and L. edodes (5, 10 and 20%) supplementation. In liver tissues, it was observed that lipid accumulation was reduced by treatment with eritadenine and L. edodes. In addition, it was revealed that the formation of atherosclerotic plaques due to the HFD was also suppressed by eritadenine and L. edodes. The results of the study indicated that the consumption of an HFD may inhibit CYP7A1 expression in the liver by increasing serum T-CHO, LDL and TG levels. L. edodes may help regulate lipid metabolism, suggesting that this fungus ameliorates hypercholesterolemia in mice by regulating CYP7A1 expression in the liver.

Preventive effects of Lentinus edodes on homocysteinemia in mice

Homocysteinemia is associated with cardiovascular and neuronal degenerative diseases. Deficiencies of the B vitamins lead to high homocysteine serum levels. Lentinus edodes (L. edodes) is also known as the Shiitake mushroom and may have beneficial effects on vascular and lipid metabolic diseases, including hypertension, homocysteinemia and lipidemia. In this study, we induced a homocysteinemia-like condition in mice by the administration of a folate- and vitamin B12-deficient diet and evaluated the effect of L. edodes on the homocysteinemia-like condition. Homocysteinemia was induced by the administration of a diet deficient in folate and vitamin B12 (DFV) for 6 weeks to mice aged 4–10 weeks. The homocysteinemic mice were treated with L. edodes flour (5, 10 and 20%), eritadenine (10 mg/kg) or DFV only (negative control) for 2 weeks. The DFV induced a significant increase in serum homocysteine levels. The increased homocysteine serum levels were reduced by eritadenine and L. edodes flour (5, 10 and 20%). Hepatic levels of S-adenosyl-L-homocysteine hydrolase (SAH) were significantly higher under DFV administration and the elevated SAH levels were reduced by treatment with L. edodes in a dose-dependent manner. The mRNA expression levels of DNA methyl transferases, DNMT1 and DNMT3a, were reduced in the DFV group, and the reduced levels of DNMT1 and DNMT3a mRNA expression were recovered in the eritadenine and L. edodes (5, 10 and 20%) groups. These results suggest that components of L. edodes, including eritadenine may have beneficial effects on hyperhomocysteinemia and its therapeutic effects may be involved in the regulation of DNA methylation-related genes in mice.

Dietary Shiitake Mushroom (Lentinus edodes) Prevents Fat Deposition and Lowers Triglyceride in Rats Fed a High-Fat Diet

High-fat diet (HFD) induces obesity. This study examined the effects of Shiitake mushroom on the prevention of alterations of plasma lipid profiles, fat deposition, energy efficiency, and body fat index induced by HFD. Rats were given a low, medium, and high (7, 20, 60 g/kg = LD-M, MD-M, HD-M) Shiitake mushroom powder in their high-fat (50% in kcal) diets for 6 weeks. The results showed that the rats on the HD-M diet had the lowest body weight gain compared to MD-M and LD-M groups (P < 0.05). The total fat deposition was significantly lower (-35%, P < 0.05) in rats fed an HD-M diet than that of HFD group. Interestingly, plasma triacylglycerol (TAG) level was significantly lower (-55%, P < 0.05) in rats on HD-M than HFD. This study also revealed the existence of negative correlations between the amount of Shiitake mushroom supplementation and body weight gain, plasma TAG, and total fat masses.

Analysis of polar lipids in the serum from rats fed shiitake by liquid chromatography-mass spectrometry/mass spectrometry

Consumption of a shiitake mushroom diet has been reported to have effects on serum phospholipids. However, much less is known about the effect on serum polar lipids including lysophospholipids and free fatty acids. In the present study, the effects of a shiitake diet were evaluated on the basis of identification and quantification of individual polar lipid components in rat serum using liquid chromatography-mass spectrometry/mass spectrometry. By comparison with standards and published data, 50 lysophospholipids and 32 free fatty acids were identified, and the concentrations of 27 polar lipids in rat serum were determined. Shiitake diets decreased the levels of all individual polar lipid components in the serum of male rat. The total level of serum polar lipids in males fed 4% shiitake diets (1365.71 mol/L) was significantly lower than that of the control (2270.26 mol/L). However, shiitake diets did not significantly affect the levels of serum polar lipids in female rats.

Dietary capsanthin, the main carotenoid in paprika (Capsicum annuum), alters plasma high-density lipoprotein-cholesterol levels and hepatic gene expression in rats

The effects of dietary capsanthin, the main carotenoid in paprika (Capsicum annuum), on lipid metabolism were examined. Young male Wistar rats were fed diets containing paprika powder, paprika organic solvent extract, residue of paprika extract, and purified capsanthin. Administration of purified capsanthin for 2 weeks resulted in a significant increase in plasma HDL-cholesterol (P < 0·05) without detectable differences in plasma total cholesterol and TAG concentrations. A statistically significant correlation (r 0·567; P < 0·001) was found between dietary capsanthin concentrations and plasma HDL-cholesterol concentrations. Animals receiving diets containing two different capsanthin concentrations exhibited dose-dependent increases in plasma HDL-cholesterol (r 0·597; P < 0·005). While capsanthin was absent in the liver of animals fed the basal diet, it increased markedly in capsanthin-fed animals (P < 0·001). Quantitative analyses of hepatic mRNA levels revealed that capsanthin administration resulted in up-regulation of mRNA for apoA5 and lecithin cholesterol acyltransferase (LCAT), without significant differences in other mRNA levels related to HDL-cholesterol metabolism. These results suggest that capsanthin had an HDL-cholesterol-raising effect on plasma, and the potential to increase cholesterol efflux to HDL particles by increasing apoA5 levels and/or enhancement of LCAT activity.

Production of the bioactive compound eritadenine by submerged cultivation of shiitake (Lentinus edodes) mycelia

Fruit bodies and mycelia of shiitake mushroom ( Lentinus edodes) have been shown to contain the cholesterol-reducing compound eritadenine, 2( R),3( R)-dihydroxy-4-(9-adenyl)butyric acid. In the search for a production method for eritadenine, shiitake mycelia were investigated in the present study. The mycelia were cultivated both in shake flasks and in bioreactors, to investigate the effects of pH, stirring rate, and reactor type on the production and distribution of eritadenine. Both the biomass and the culture broth were examined for their eritadenine content. In the shake flasks, the final concentration of eritadenine was 1.76 mg/L and eritadenine was equally distributed between the mycelia and the growth media. In the bioreactors, the shiitake mycelia were found to contain eritadenine in relatively low levels, whereas the majority, 90.6-98.9%, was detected in the growth media. Applying a stirring rate of 250 rpm during bioreactor cultivation resulted in the highest eritadenine concentrations: 10.23 mg/L when the pH was uncontrolled and 9.59 mg/L when the pH was controlled at 5.7. Reducing the stirring rate to 50 rpm resulted in a decreased eritadenine concentration, both at pH 5.7 (5.25 mg/L) and when pH was not controlled (5.50 mg/L). The mycelia in the shake flask cultures appeared as macroscopic aggregates, whereas mycelia cultivated in bioreactors grew more as freely dispersed filaments. This study demonstrates for the first time the extra- and intracellular distribution of eritadenine produced by shiitake mycelial culture and the influence of reactor conditions on the mycelial morphology and eritadenine concentrations.

Structure and function of eritadenine and its 3-deaza analogues: Potent inhibitors of S-adenosylhomocysteine hydrolase and hypocholesterolemic agents

d-Eritadenine (DEA) is a potent inhibitor of S-adenosyl-l-homocysteine hydrolase (SAHH) and has hypocholesterolemic activity. We have hypothesized that 3-deaza-DEA (C3-DEA) and its analogues retain high level of SAHH inhibitory activity and have resistance to deamination and glycosidic bond hydrolysis in vivo. Such C3-DEA analogues would have much higher hypocholesterolemic activity. C3-DEA, and its methyl ester (C3-OMeDEA) and its methyl amido (C3-NMeDEA) were synthesized to examine their SAHH inhibitory and hypocholesterolemic activities. A crystal structure of SAHH containing C3-DEA was determined and confirmed that DEA and C3-DEA bound to the same site of SAHH with the same binding mode. The SAHH inhibitory activities of C3-DEA (K(I)=1.5 microM) and C3-OMeDEA (K(I)=1.5 microM) are significantly lower than that of DEA (K(I)=30 nM), while rats fed by C3-DEA and C3-OMeDEA decrease the total plasma cholesterol and phospholipids by 36-40% and 23%, respectively, which is similar to the level of reductions (42% and 27%) by DEA. C3-NMeDEA lost most of the SAHH inhibitory activity (K(I)=30 microM) and dietary C3-NMeDEA does not decrease cholesterol and phospholipid in plasma but decreases the triacylglycerol level by 16%. DEA and C3-DEA analogues are neither substrates nor inhibitors of adenosine deaminase.