Nattokinase as a functional food ingredient:therapeutic applications and mechanisms in age-related diseases

Consumption of natto,a traditional eastern Asian food made of fermented soybeans by Bacillus subtilis,has long been linked to healthy aging and longer human lifespan.As the key thrombolytic ingredient of natto,the serine protease nattokinase(NK)has been developed into a widely-used dietary supplement.NK has shown excellent anti-thrombus,thrombolytic,and anti-inflammation activities that potentially delay aging and provide therapeutic effects on aging-related diseases.In this review,we critically overview the experimental and clinical evidence in the past 20 years that support the beneficial function of NK in the prevention and treatment of aging-related diseases,including cardiovascular diseases,Alzheimer’s disease,other abnormalities and cancer.We focus on the underlying molecular mechanisms and recent advances in application methods that are aimed at further development of NK for healthier aging of modern society.The challenges and unsolved issues in this area are also discussed.

Degradation of amyloid β-peptides catalyzed by nattokinase in vivo and in vitro

Amyloid-β 1-42(Aβ42)plays a pivotal role in Alzheimer disease(AD)pathogenesis. Peripheral clearance of Aβ42 largely affects its level in the brain and affects AD progression. Although nattokinase(NK)degrades Aβ40, the details of NK's capture of various Aβ species and reduction of plasma Aβ42/Aβ40 are uncharacterized. In this study, the Aβ42/Aβ40-degrading ability of NK was investigated using five Aβs and AD model mice. The C-terminal region of Aβ42/Aβ40(Gly29 to Val40)was primarily required for NK capture, and the integrated conformation in Aβ42/Aβ40 aggregates was a more efficient target for NK catalysis. Further, suspended Aβ42/Aβ40 oligomers were more easily captured by NK than suspended Aβ42/Aβ40 fibrils, while deposited Aβ42/Aβ40 fibrils recruited more NK than deposited Aβ42/Aβ40 oligomers. Although most NK was likely lost during NK uptake and/or entry into the blood, a small fraction of NK showed good plasma Aβ42/Aβ40-degrading efficacy after entering the blood due to NK's stability in the plasma of AD mice for at least 9 days. It was concluded that oral administration of NK is a feasible approach for peripheral Aβ42/Aβ40 clearance. This implies that NK might serve as an anti-Aβ42 agent for the treatment of Aβ42/Aβ40-related diseases such as AD.

Preparation and evaluation of nattokinaseloaded self-double-emulsifying drug delivery system

In the present study,we prepared nattokinase-loaded self-double-emulsifying drug delivery system(SDEDDS)and investigated its preliminary pharmacodynamics.The type and concentration of oil phase,inner aqueous phase and emulsifier were screened to prepare optimum nattokinase-loaded SDEDDS.Next,the optimum formulations were characterized based on microstructure,volume-weighted mean droplet size,self-emulsifying rate,yield,storage stability,in vitro release and in vivo pharmacodynamics studies.The water/oil/watermultiple emulsions exhibited typicalmultiple structure,with relatively small volumeweighted mean droplet size 6.0±0.7μm and high self-emulsifying ability(self-emulsifying time<2 min).Encapsulation of nattokinase was up to 86.8±8.2%.The cumulative release of nattokinase within 8 h was about 30%,exhibiting a sustained release effect.The pharmacodynamics study indicated that nattokinase-loaded SDEDDS could significantly prolong the whole blood clotting time in mouse and effectively improve the carrageenan-induced tail thrombosis compared with nattokinase solution.Moreover,we showed that SDEDDS could successfully self-emulsify into water/oil/water multiple emulsions upon dilution in dispersion medium with gentle stirring and effectively protect nattokinase activity in gastric environment.Our findings suggested that SDEDDS could be a promising strategy for peptide and protein drugs by oral administration.

Preparation and toxicity evaluation of a novel nattokinase-tauroursodeoxycholate complex

Nattokinase(NK), which has been identified as a potent fibrinolytic protease, has remarkable potential in treatment of thrombolysis, and even has the ability to ameliorate chronic vein thrombosis. To reduce the hemorrhagic risk from an intravenous injection of NK,nattokinase-tauroursodeoxycholate(NK-TUDCA) complex was prepared at different pH values and with different ratios of NK and TUDCA. When assessing survival time, survival state,tail injury, and the body weight of mice, it was found that the NK-TUDCA complex(NK: 10 k IU/ml; TUDCA: 10 mg/ml; pH 5.0) had a lower toxicity when administered at an NK dosage of 130 kIU/kg in the acute toxicity test and 13 kIU/kg in the repeated low-dose challenge. From the results of the in vitro thrombolytic test and characterization of NKTUDCA, we speculated that the delayed release of NK-TUDCA might be the main cause of toxicity reduction by the complex. This study described the preparation of an NK complex with low toxicity following intravenous administration, which could be utilized for further clinical study of NK.

Studies on a Novel Fibrinolytic Enzyme(Nattokinase)in the Vegetable Cheese Natto

The culture condition of bacillus strain and the extraction method of Nattokinase were reported. The fibrinolytic activity of nattokinese was appraised.

In vitro and in silico studies on fibrinolytic activity of nattokinase： A clot buster from Bacillus sp.

BACKGROUND： Nattokinase （NK） is a serine protease enzyme of the subtilisin family. It exhibits a strong fibrinolytic activity. The fibrinolytic enzymes from Bacillus sp. have attracted interest as thrombolytic agents because of their efficiency in the fibrinolytic process including plasmin activation. METHODS： In the present study, VIT garden soil was collected and subjected to isolation process in order to screen for the NK production. Screening for NK enzyme was performed by radial caseinolytic assay. The production of NK enzyme was done in two different production medium for comparative studies. The NK enzyme was purified by gel permeation chromatography. The activity of the purified NK was checked by clot lysis and casein digestion assay. To investigate the structural basis of NK and fibrinogen interaction and also to identify the best binding mode, molecular dynamics and docking studies were performed. RESULTS： Based on the morphological and biochemical characterization, the isolate was identified as Bacillus sp. The overall purification fold of NK was about 3 with the specific activity of 664U/mg and 9.9% yield. Homogeneity of the purified enzyme was analyzed and confirmed by the single band obtained in SDS-PAGE. Molecular weight of the purified protease was estimated as 25 kDa. Purified NK enzyme exhibited 97% of effective clot lysis activity. The NK was docked in to the knob region of the fibrinogen at its binding site using Dock server. A total of 26 residues of fibrinogen and 29 residues of NK constitute the interface region. However, 9 residues offibrinogen （THR238, MET264, LYS266, ARG275, THR277, ALA279, ASN308, MET310, and LYS321） and 8 residues ofNK （GLY61, SER63, THR99, PHE189, LEU209, TYR217, ASN218, and MET222） are involved in intact binding. CONCLUSIONS： A significant amount of NK enzyme was obtained from Bacillus sp. The docking analysis revealed that the NK and fibrinogen adopt an extended binding pattern and interacts with the crucial residues to exhibit their activity.

Thermostability of Subtilisin Nattokinase Obtained by Site-Directed Mutagenesis

To study the thermostability of Nattokinase（subtilisin NAT,NK）,three double mutant plasmids（pET-28a-NKG61C/S98C,pET-28a-NKT22C/S87C,pET-28a-NKS24C/S87C）were constructed by site-directed mutagenesis.Target enzymes were detected using SDS-PAGE and disulfide bond formation was detected using Western blotting analysis.Thermostability was tested by rates of inactivation at certain temperature.The results showed that disulfide bond was not formed within two cysteines and the thermostability of three double mutants was not increased compared with the wild-type NK.The thermostability of NK performed in Ca2＋was stronger than in ethylenediaminetetraacetic acid（EDTA）.But when the temperature reached 62℃,the enzymes rapidly denatured and inactivated even in the presence of Ca2＋.Although the thermostability of mutants was not increased,this study shows a tendency of improving thermostability of NK in protein engineering.

响应面法优化鹰嘴豆发酵纳豆工艺

鹰嘴豆作为纳豆发酵原料,以纳豆激酶(Nattokinase,NK)活性为指标,在单因素实验的基础上,利用Box-Behnken实验设计以及响应面分析优化纳豆发酵工艺。研究结果表明,鹰嘴豆的最佳发酵工艺条件为:基质含水量50%,接种量6%,发酵温度34℃,发酵时间48h,后熟时间20h;对优化的工艺条件进行验证,纳豆激酶活性为986.324IU/g,与预测值接近。

Cloning and Expression of One Fibrinolytic Enzyme from Bacillus sp. zlw-2

The gene encoding fibrinolytic enzyme from Bacillus sp. zlw-2 was cloned and sequenced （accession no. EU734749）, which was 1146 bp, encoded 381 amino acids and had 99% homology with Nattokinase YF308 and NAT. The genes encoding pre-pro-fibrinolytic enzyme （including signal peptide, propeptide, and mature peptide） and fibrinolytic enzyme （including mature peptide） were cloned into pET28a vector respectively and then transformed into Escherichia coli BL21 （DE3）. The recombinant ofpre-pro-fibrinolytic enzyme showed enzyme activity of 183 U mL^-1, while no detectable enzyme activity could be found from the recombinant of the mature peptide.

Analysis of Main Components and Prospects of Natto

The word “natto” originated from Japan, which was known as stinky bean, salt bean or silk bean in Chinese folk. Natto contains multiple functional components, including nattokinase, soybean isoflavone, γ-polyglutamic acid, vitamin K2, biogenic amines, SOD, small-molecule polypeptide, which has good preventive and curative effects for many diseases, such as cardiovascular and cerebrovascular diseases, hyperlipidemia, hypertension, menopausal symptoms and hypoimmunity. Along with the aging population in the world and China, it is urgent to improve the quality of life. It is necessary to enhance the understanding of natto-related knowledge, expand propaganda power, accept natto consciously and eat natto frequently, which is good for our health and helps our country to build a healthy and harmonious society. This review will descript the development, components, functions and prospects of natto, which help us to offer theoretical basis for promoting natto industry.