Spices as Sustainable Food Preservatives: A Comprehensive Review of Their Antimicrobial Potential

Antilisterial activity of Thymus vulgaris essential oil: In vitro, in situ, and in silico investigations

Listeria monocytogenes is a major foodborne pathogen that significantly threatens public health and food safety. While Thymus vulgaris essential oil (TV-EO) is widely recognized for its potent antibacterial activity, its specific effects against L. monocytogenes remain unexplored. This study aimed to assess the antilisterial activity of TV-EO using in vitro, in situ, and in silico approaches. The in vitro assessment included disc diffusion method, determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), biofilm inhibition assay, and predictive modeling to assess L. monocytogenes reduction in the presence of TV-EO at 10 °C and 20 °C. In situ approach evaluated the inhibitory effect of TV-EO on L. monocytogenes in minced poultry meat stored at 4 °C. Finally, in silico approach, based on molecular docking, was employed to evaluate the binding affinity of major TV-EO components for β-ketoacyl-ACP synthase II and chorismate synthase, key proteins involved in fatty acid biosynthesis and biofilm formation, respectively. Our finding revealed that TV-EO exhibited strong in vitro antilisterial activity, with inhibitory zones ranging from 51.00 ± 1.00 mm to 55.67 ± 1.15 mm, a MIC value of 0.125 %, and a MBC value of 0.25 %, indicating its bactericidal effect. TV-EO at 0.125 % demonstrated a high capacity to inhibit and eradicate the biofilm, with 100 ± 0.00 % and 91.33 ± 1.23 %, respectively. Predictive modeling, based on the combination of TV-EO and ζ values, revealed that L. monocytogenes inactivation was more pronounced at low temperature. Furthermore, the in-situ approach showed a significant reduction of L. monocytogenes amount, with decreases of 1.068 ± 0.132 log cfu/g, 0.671 ± 0.091 log cfu/g, and 0.317 ± 0.029 log cfu/g at TV-EO concentrations of 1 %, 0.5 %, and 0.25 %, respectively (p < 0.05). In silico analysis indicated that TV-EO components, particularly carvacrol, exhibited high affinity for β-ketoacyl-ACP synthase II and chorismate cynthase, suggesting strong antilisterial and ani-biofilm activity. These findings highlight the antilisterial efficacy of TV-EO, demonstrating its potential as a natural alternative to conventional preservatives for enhancing food preservation and safety.

Sensory preferences are important motivators for using herbs and spices: A cross-sectional analysis of Australian adults

INTRODUCTION

Herbs and spices have been used in cooking and food preparation to add flavour and aroma for centuries. However, many herbs and spices are also associated with a number of health benefits. Despite this, little is known about the types and frequency of use of herbs and spices in Australian households. Therefore, the aim of this study was to determine the types of herbs and spices used in cooking and food preparation in Australian households.

METHODS

A cross-sectional study was undertaken amongst Australian adults aged ≥18 years. Participants were recruited via social media platforms requesting voluntary participation in an online questionnaire. The survey tool included questions related to the types of herbs and spices used and consumed in Australian households, frequency of use, and adherence to a Mediterranean diet (MedDiet) using the Mediterranean Diet Adherence Screener.

RESULTS

A total of n = 400 participants responded and completed the survey. Participants were mostly female (n = 341; 85.3%) aged between 25 and 64 years (n = 331; 82.8%) and were overweight (body mass index: 26.5 ± 5.9 kg/m2). In the previous 12 months, two-thirds of participants (n = 257; 64.3%) reported consuming herbs and spices 1-2 times per day, which were mostly consumed as part of lunch/dinner meals (n = 372; 93%). Basil (n = 391; 97.8%), pepper (n = 390; 97.5%) and garlic (n = 387; 96.8%) were amongst the most frequently used herbs and spices. Moderate to high adherence to a MedDiet was associated with daily use of herbs and spices [χ2 (1, n = 397) = 5.6, P = 0.018].

CONCLUSION

This cross-sectional analysis of Australian households shows that most Australian adults consume herbs and spices daily. Further investigation into the quantities used and needed to elicit potential health benefits of herbs and spices when incorporated into a healthy dietary pattern warrants future investigation.

Postbiotics in the Bakery Products: Applications and Nutritional Values

In recent years, the consumption of postbiotics has gained significant attention due to their potential health benefits. However, their application in the bakery industry remains underutilized. This review focuses on recent advances in the use of postbiotics, specifically the metabolites of lactic acid bacteria, in bakery products. We provide a concise overview of the multifaceted benefits of postbiotics, including their role as natural antioxidants, antimicrobials, and preservatives, and their potential to enhance product quality, extend shelf-life, and contribute to consumer welfare. This review combines information from various sources to provide a comprehensive update on recent advances in the role of postbiotics in bakery products, subsequently discussing the concept of sourdough as a leavening agent and its role in improving the nutritional profile of bakery products. We highlighted the positive effects of postbiotics on bakery items, such as improved texture, flavor, and shelf life, as well as their potential to contribute to overall health through their antioxidant properties and their impact on gut health. Overall, this review emphasizes the promising potential of postbiotics to revolutionize the bakery industry and promote healthier and more sustainable food options. The integration of postbiotics into bakery products represents a promising frontier and offers innovative possibilities to increase product quality, reduce food waste, and improve consumer health. Further research into refining techniques to incorporate postbiotics into bakery products is essential for advancing the health benefits and eco-friendly nature of these vital food items.

Temperature cycling between 4 °C and 37 °C could reduce Salmonella viability in low-moisture foods

Low-moisture foods (LMFs) have been linked to Salmonella transmission due to the remarkable resilience of Salmonella against desiccation, allowing its survival for extended periods. Being metabolically inactive, Salmonella in LMFs exhibit extraordinary resistance to inactivation treatments. This study proposes a novel strategy for mitigating Salmonella in LMF products through a temperature cycling (TC) approach. Alternating the temperature between 4 °C and 37 °C on a daily basis reduced the viability of S. Typhimurium air-dried on surfaces by >4 log after 6 days. TC also diminished Salmonella resistance to acidity and reduced its virulence. The mechanism was elucidated through an integrated analysis of transcriptomics and proteomics data. Specifically, transcriptomic data revealed elevated levels of protein synthesis alongside active energy metabolism. Proteomic analysis demonstrated that these protein activities were associated primarily with the heat shock protein response. Taken together, the principal mechanism by which TC exerts its inhibitory effect appears to be the repeated induction of heat shock protein synthesis within Salmonella, ultimately leading to energy depletion. Finally, the efficacy of TC was validated on representative LMF samples, including flour, protein powder, and mixed spices. The most notable effect was observed in the mixed spices, with a reduction of 2.7 ± 0.2 log after 6 days (P < 0.05). In conclusion, the TC approach demonstrated in this study provides valuable insights into the management of foodborne pathogens in LMFs.

Zingiber officinale Uncovered: Integrating Experimental and Computational Approaches to Antibacterial and Phytochemical Profiling

BACKGROUND

Zingiber officinale rhizome is widely cultivated in the central region of Sudan (Gezira) and data on the biological properties of this variety grown in Sudan's climate are scarce. This study aims to comprehensively analyze the antibacterial, antioxidant, phytochemical, and GC-MS properties of Zingiber officinale (ginger rhizome) to explore its potential applications.

METHODS AND RESULTS

The in vitro antibacterial assessment of the aqueous extract of Sudanese ginger revealed moderate activity against Staphylococcus aureus, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia, as determined by the disc diffusion method. The inhibition zones ranged from 12.87 ± 0.11 mm to 14.5 ± 0.12 mm at 30 µg/disc. The minimum inhibitory concentration ranged from 6.25 to 25 µg/mL, while the MBC ranged from 25 to 50 µg/mL. The MBC/MIC exhibited a bactericidal effect against all tested bacteria. Phytochemical screening revealed the presence of various chemical constituents, such as saponins, flavonoids, glycosides, alkaloids, steroids, terpenoids, and the absence of tannins in Sudanese ginger rhizome. Furthermore, GC-MS analysis of ginger rhizome identified 22 chemical compounds with retention times ranging from 7.564 to 17.023 min. The identification of 22 chemical compounds through GC-MS analysis further underscores the prospect of harnessing ginger rhizome for the development of novel medications. Computational analyses showed that ginger compounds bind the Protein Data Bank (PDB) codes 1JIJ and 2QZW with high binding affinities, reaching -9.5 kcal/mol. Ginger compounds also established promising molecular interactions with some key residues, satisfactorily explaining the in vitro results and supporting the pharmacokinetic and experimental findings.

CONCLUSIONS

This study lays the groundwork for future research and pharmaceutical exploration aimed at harnessing the beneficial properties of ginger rhizome for medicinal and therapeutic purposes, particularly its antimicrobial potential.

Antimicrobial and antioxidant study of combined essential oils of Anethum Sowa Kurz. and Trachyspermum ammi (L.) along with quality determination, comparative histo-anatomical features, GC‒MS and HPTLC chemometrics

Spices played crucial and variable roles in traditions, culture, history, religious ceremonials and festivals along with fetching food flavor and microbial protection globally due to presence of structurally unique and multi-natured chemotypes. Their existence in dishes portrayed key roles in improving shelf life by regulating spoilage of cuisine with different synergistic mechanism. Histo-anatomically (A) sowa exhibited distinguished cellular attributes which created remarkable differences with T. ammi. HPTLC chemometrics of both fruits revealed several peaks for active metabolomics with unique isocratic combination of menstruum. GC-MS study of hydro-distillate exhibited presence of monoterpenic cyclic and aromatic hydrocarbons, alcoholic and ketonic groups along with phenolic derivative that covers majorly 90% of total metabolites. Combined essential oils (EOs 1 + 2) of both fruits showed excellent antimicrobial activity against various clinical pathogenic strains such as K. pneumoniae at 10 µL/mL, S. aureus at 2.5 µL/mL, E. coli and E. faecalis at 1.25 µL/mL, and MRSA and Bcereus at 0.625 µL/mL and (C) albicans at 0.312 µL/mL as the MIC. The antioxidant study of (EOs 1 + 2) with maximum inhibition percentage to DPPH assay was 84.02 ± 1.05 at 100 µg/mL, and minimal inhibition was 72.31 ± 0.63 at 5 µg/mL with IC50 value 4.69 ± 0.22 µg/mL, while ABTS assay extreme was 79.15 ± 2.14 µg/mL and minimal was 67 ± 1.34 with the IC50 value of 18.37 ± 0.15 µg/mL, in superoxide assay uppermost inhibition was 81.03 ± 0.27 µg/mL and lowest was at 65.16 ± 3.15 with the IC50 value 16.46 ± 0.54, and H2O2 radical scavenging activity, predominant value was 78.01 ± 0.47 and least was 64.1 ± 2.01 with IC50 15.58 ± 0.34. These comparative key diagnostic features and synergistic effect of multicomponent natural antimicrobials will provide profound intellect of ancient utility and further scientists to explore their multiple mechanistic modality and application in food and beverages industry.

Changes in flavor profile of vegetable seasonings by innovative drying technologies: A review

Seasonings like garlic, ginger, and scallion provide spicy and masking flavor or aroma in vegetables. However, the method or technique used for drying these spices can affect the flavor profile. Therefore, this review focuses on vegetable seasonings like ginger, garlic, and scallion, the characteristic flavor of fresh and dehydrated vegetable seasoning, and how drying methods (freeze-drying [FD], convective hot air drying [HAD], infrared drying, microwave drying [MW]), and other recent dryers (swirling fluidized bed [SFB], pulsed-vacuum dryer, relative humidity-convective dryer, etc.) affect the flavor profile of the common vegetable seasonings. HAD increases α-zingiberene, reduces gingerol, and forms β-citral and citral in fresh ginger. FD increased sesquiterpenes, retained terpenoids, sulfides, and other volatiles in fresh ginger, and did not produce new volatile compounds (VOCs) in garlic. SFB drying better preserves 6-gingerol than FD and HAD. MW increases trisulfides and cyclic sulfur compounds in garlic. In general, drying, especially thermal drying reduces the VOCs in fresh garlic, ginger, and scallion and causes the formation of new VOCs.

Impact of Drying Methods on Phenolic Composition and Bioactivity of Celery, Parsley, and Turmeric-Chemometric Approach

Drying is one of the most commonly used methods for food preservation, and in spice processing, it has a significant impact on quality. In this paper, the influences of drying at room temperature, 60 °C, and 90 °C and freeze-drying on celery and parsley roots and turmeric rhizomes were examined. The highest content of total phenolics was found in celery dried at 60 °C (C60), parsley at room temperature (PRT), and freeze-dried turmeric (TFD) (1.44, 1.58, and 44.92 mg GAE/gdm, respectively). Celery dried at room temperature (CRT), PRT, and TFD showed the highest antioxidant activity regarding the DPPH and ABTS radicals and FRAP. The analysis of color parameters revealed that celery dried at 90 °C (C90); PFD and TFD showed the most similar values to control samples. The drying process was optimized using a combination of standard score (SS) and artificial neural network (ANN) methods. The ANN model effectively evaluated the significance of drying parameters, demonstrating high predictive accuracy for total phenolics, total flavonoids, total flavonols, total flavan-3-ols, IC50ABTS, and FRAP. TFD showed the strongest α-glucosidase inhibitory potential. Also, TFD extract showed good antibacterial activity against Staphylococcus aureus but not against Escherichia coli. C90 and PFD extracts did not show antibacterial activity against the tested microorganisms.

Antibacterial and anticancer potential of bioactive compounds and secondary metabolites of endophytic fungi isolated from Anethum graveolens

Fungal endophytes are known to produce bioactive chemicals and secondary metabolites that are often identical to those produced by their host plants. The main objective of the current study was to isolate and identify endophytic fungi associated with the medicinal plant Anethum graveolens, and to investigate their potential antibacterial and anticancer properties. The ethyl acetate extracts from the isolated endophytic fungi, as well as the host plant A. graveolens, were subjected to bioactivity assays to evaluate their antibacterial and anticancer potential against multi-drug resistant bacterial strains and the human hepatocellular carcinoma cell line HepG2. The endophytic fungi isolated and identified from the A. graveolens samples included Diaporthe, Auxarthron, Arthrinium, Aspergillus, Microsporum, Dothiorella, Trichophyton, Lophiostoma, Penicillium, and Trichoderma species. The minimum inhibitory concentration (MIC) assay revealed that the A. graveolens extract exhibited the strongest antibacterial activity, with an MIC value of 4 μg/ml, followed by the Trichoderma sp. (5 μg/ml) and Penicillium sp. (6 μg/ml) extracts. Additionally, the crude extracts of Trichoderma sp., Penicillium sp., and Fusarium sp. demonstrated high anticancer activity against HepG2 cells, with inhibition rates ranging from 89 to 92% at a concentration of 50 μg/ml. Interestingly, the A. graveolens extract showed the most potent anticancer activity, with a 95% inhibition rate against HepG2 cells at the same concentration. These findings highlight the significant potential of endophytic fungi associated with A. graveolens, as a source of bioactive compounds with promising antibacterial and anticancer properties. The results reinforce the hypothesis that medicinal plants and their endophytic fungi can serve as an attractive alternative for the development of novel therapeutic agents, potentially offering a more sustainable and less harmful approach to disease management compared to traditional chemical-based methods.

Harnessing medicinal plant compounds for the control of Campylobacter in foods: a comprehensive review

Campylobacter is a major foodborne and zoonotic pathogen, causing severe human infections and imposing a substantial economic burden on global public health. The ongoing spread and emergence of multidrug-resistant (MDR) strains across various fields exacerbate therapeutic challenges, raising the incidence of diseases and fatalities. Medicinal plants, renowned for their abundance in secondary metabolites, exhibit proven efficacy in inhibiting various foodborne and zoonotic pathogens, presenting sustainable alternatives to ensure food safety. This review aims to synthesize recent insights from peer-reviewed journals on the epidemiology and antimicrobial resistance of Campylobacter species, elucidate the in vitro antibacterial activity of medicinal plant compounds against Campylobacter by delineating underlying mechanisms, and explore the application of these compounds in controlling Campylobacter in food. Additionally, we discuss recent advancements and future prospects of employing medicinal plant compounds in food products to mitigate foodborne pathogens, particularly Campylobacter. In conclusion, we argue that medicinal plant compounds can be used as effective and sustainable sources for developing new antimicrobial alternatives to counteract the dissemination of MDR Campylobacter strains.

The Potential of Thymus serpyllum Essential Oil as an Antibacterial Agent against Pseudomonas aeruginosa in the Preservation of Sous Vide Red Deer Meat

Foodborne infections caused by microbes are a serious health risk. Regarding this, customer preferences for "ready-to-eat" or minimally processed (MP) deer meat are one of the main risk factors. Given the health dangers associated with food, essential oil (EO) is a practical substitute used to decrease pathogenic germs and extend the shelf-life of MP meals. Nonetheless, further data regarding EO use in MP meals are required. In order to evaluate new, safer alternatives to chemicals for disease control and food preservation, this research was carried out in the following areas to assess the antibacterial and antibiofilm characteristics of Thymus serpyllum (TSEO) essential oil, which is extracted from dried flowering stalks. Furthermore, this study applied an essential oil of wild thyme and inoculated the sous vide deer meat with Pseudomonas aeruginosa for seven days at 4 °C in an effort to prolong its shelf-life. Against P. aeruginosa, the essential oil exhibited potent antibacterial action. The findings of the minimal biofilm inhibition concentration (MBIC) crystal violet test demonstrated the substantial antibiofilm activity of the TSEO. The TSEO modified the protein profiles of bacteria on glass and plastic surfaces, according to data from MALDI-TOF MS analysis. Moreover, it was discovered that P. aeruginosa was positively affected by the antibacterial properties of TSEO. The anti-Pseudomonas activity of the TSEO was marginally higher in vacuum-packed sous vide red deer meat samples than in control samples. The most frequently isolated species from sous vide deer meat, if we do not consider the applied bacteria Pseudomonas aeruginosa, were P. fragi, P. lundensis, and P. taetrolens. These results highlight the antibacterial and antibiofilm qualities of TSEO, demonstrating its potential for food preservation and extending the shelf-life of deer meat.

Recent Advances in Astaxanthin as an Antioxidant in Food Applications

In recent years, astaxanthin as a natural substance has received widespread attention for its potential to replace traditional synthetic antioxidants and because its antioxidant activity exceeds that of similar substances. Based on this, this review introduces the specific forms of astaxanthin currently used as an antioxidant in foods, both in its naturally occurring forms and in artificially added forms involving technologies such as emulsion, microcapsule, film, nano liposome and nano particle, aiming to improve its stability, dispersion and bioavailability in complex food systems. In addition, research progress on the application of astaxanthin in various food products, such as whole grains, seafood and poultry products, is summarized. In view of the characteristics of astaxanthin, such as insolubility in water and sensitivity to light, heat, oxygen and humidity, the main research trends of astaxanthin-loaded systems with high encapsulation efficiency, good stability, good taste masking effect and cost-effectiveness are also pointed out. Finally, the possible sensory effects of adding astaxanthin to food aresummarized, providing theoretical support for the development of astaxanthin-related food.

Identification of cholinesterases inhibitors from flavonoids derivatives for possible treatment of Alzheimer's disease: In silico and in vitro approaches

Nowadays, one of the methods to prevent the progress of Alzheimer's disease (AD) is to prescribe compounds that inhibit the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Researchers are actively pursuing compounds, particularly of natural origin, that exhibit enhanced efficacy and reduced side effects. The inhibition of AChE and BChE using natural flavonoids represents a promising avenue for regulating AD. This study aims to identify alternative flavonoids capable of modulating AD by down-regulating AChE and BChE activity through a molecular docking approach. Molecular docking analysis identified Ginkgetin and Kolaflavanone as potent inhibitors of AChE and BChE, respectively, among the selected flavonoids. Asn87 and Ala127 involved in the interactions of AChE-Ginkgetin complex through conventional hydrogen bonds. While in the BChE-Kolaflavanone complex, Asn83, Ser79, Gln 47, and Ser287 are involved. In vitro analysis further corroborated the inhibitory potential, with Ginkgetin exhibiting an IC50 of 3.2 mM against AChE, and Kolaflavanone displaying an IC50 of 3.6 mM against BChE. These findings underscore the potential of Ginkgetin and Kolaflavanone as candidate inhibitors for the treatment of AD through the inhibition of AChE and BChE enzymes. Nevertheless, additional in vitro and in vivo studies are imperative to validate the efficacy of these compounds.

Nutritional Value and in vitro Antigiardial Activity of Anise (Pimpinella anisum L.) Seeds

The present study focused on evaluating the proximate analysis, mineral composition, and in vitro anti-giardial activity of Pimpinella anisum seed extracts, which are aromatic plants with a long history of usage in folk and conventional medicine, as well as pharmaceutical manufacturing. Standard methods were used to determine the proximate analysis of the powdered plant sample, including dry matter, ash, fat, protein, fiber, and carbohydrates. The mineral contents of Pimpinella anisum seed were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), revealing that the plant has a high fiber content (42.62%) followed by carbohydrates (38.79%). The seeds were also found to be a rich source of minerals, with notable amounts of Rubidium, Magnesium, and Calcium. The extracts showed a high mortality percentage compared to Metronidazole, with the chloroform extract exhibiting higher anti-giardial activity (78.71%) than the ethanolic extract (75.29%) at a concentration of 500 ppm. These findings support the traditional use of Anise in treating gastrointestinal issues and as a natural supplement. Further studies are needed to isolate the active ingredients and understand their mechanism of action.

Dataset of 16S ribosomal DNA sequence-based identification of bacteriocinogenic lactic acid bacteria isolated from fermented food samples

The dataset profiled in this research is built on sequencing of lactic acid bacteria 16S rDNA mined from Nono (N4 and N5), Kunu (K4 and K1) and Garri. The 16S rDNA sequences files are accessible under the data identification numbers: OK017047, OK017046, OK017044, OK017043, OK017045 at the GenBank database, NCBI. Taxonomic identification and phylogenetic tree analysis were done using the online BLAST (blastn) and MEGA11 software, respectively. The effect of the bacteriocin produced by these organisms on spoilage bacteria associated with salad was evaluated using an agar well diffusion assay. Limosilactobacillus pontis strain EOINONO, Limosilactobacillus pontis strain OGENONO, Limosilactobacillus pontis strain SEOGARI, Lactiplantibacillus plantarum strain MJIKUNU and Limosilactobacillus pontis strain EEIKUNU were the identified bacteriocinogenic organisms while Bacillus tequilensis strain SEOABACHA, Bacillus tequilensis strain EEIABACHA, Achromobacter xylosoxidans strain IMABACHA and Achromobacter insolitus strain MJIABACHA were the identified spoilage organisms.

Unveiling the Anti-Cholera and Active Diabetic Renoprotective Compounds of Maqian Essential Oil: A Computational and Molecular Dynamics Study

Cholera is an exceptionally aggressive infectious disease characterized by the potential to induce acute, copious, watery diarrhea of considerable severity and renal inflammation. Diabetic nephropathy is a serious complication of diabetes mellitus that can lead to kidney failure through inflammation; thus, anti-inflammatory agents are promising therapies for diabetic nephropathy. Previous studies have shown that the essential oil of Zanthoxylum myriacanthum var. pubescens Huang, Maqian essential oil (MQEO), exhibits potent antibacterial, anti-inflammatory, and renoprotective activities in diabetic mice and has emerged as a potential therapeutic drug for the treatment of diabetic nephropathy complications. Therefore, the present study was carried out to screen the potential inhibition of cholera toxin and the diabetic renoprotective activity of MQEO through computational approaches. Twelve chemical constituents derived from MQEO were docked with cholera toxin and the target proteins involved in diabetic nephropathy, namely, TXNIP, Nrf2, and DPP IV, and, subsequently, the predictions of molecular dynamic simulations, the drug-likeness properties, and the ADMET properties were performed. α-terpineol showed high binding affinities toward the cholera toxin protein. For TXNIP, among all the chemical constituents, α-phellandrene and p-cymene showed strong binding affinities with the TXNIP protein and displayed relatively stable flexibility at the hinge regions of the protein, favorable physicochemical properties in the absence of hepatotoxicity, and low cytotoxicity. For Nrf2, α-terpineol exhibited the highest binding affinity and formed a very stable complex with Nrf2, which displayed high pharmacokinetic properties. All compounds had low free-binding energies when docked with the DPP IV protein, which suggests potent biological activity. In conclusion, based on a computational approach, our findings reveal that MQEO constituents have inhibitory activity against cholera toxin and are promising therapeutic agents for suppressing diabetic inflammation and for the treatment of diabetic nephropathy complications.