1 Introduction

Non-communicable diseases (NCDs) including cancer, cardiovascular, diabetes, and chronic respiratory disease account for 74% of worldwide mortality [1]. A significant amount of non-communicable disease (NCD) deaths, 86% of individuals encounter premature death before reaching the age of 70. NCDs comprise a significant portion of death and disability in adults, and risk factors are introduced at a young age [2, 3]. Chronic diseases are characterized by prolonged disorders caused by a combination of hereditary, biological, environmental, and psychological variables [2, 4]. NCDs quickly spread worldwide and have reached epidemic proportions in many countries due to globalization, industrialization, increasing urbanization, and demographic and lifestyle changes [5].

The global pandemic of non-communicable diseases creates a significant threat to sustainable growth. Non-communicable diseases (NCDs) are also included within the scope of Sustainable Development Goal (SDG) 3.4. This goal sets a target to decrease premature mortality caused by NCDs by one-third by the end of 2030. Additionally, SDG 3.4 intends to promote psychological wellness and health using early detection and treatment strategies [6, 7]. In recent years, significant growth in epidemiological data has been directly linked to the prevalence of non-communicable diseases in people of all ages. A functional food comprises any food that, in addition to basic nutrition, offers a health benefit to one or more biological processes [8, 9].

Fish protein is an essential and significant dietary component, particularly in regions with develo** and developed countries. The global population relying on fish production, processing, and trade for their livelihood is estimated to be about one billion individuals [10,11,12]. The fish processing operations yield over 60% of by-products classified as trash, including various components such as skin, head, fins, trims, frames, internal organs, and roes. Conversely, only 40% of the fish products derived from this sector are intended for consumption by humans directly [13,14,15,1 and 2). The use of fish by-product hydrolysates has shown great potential as a viable source of antioxidant peptides [102,103,104]. The investigation of eel protein hydrolysis (EPH) utilizing alcalase enzyme showed promising attributes in terms of antioxidative and anti-carcinogenic properties. The inhibition of MCF-7 (Michigan Cancer Foundation-7) cells was shown to be strongest in the treatment including 3 kDa EPH, in comparison to the treatments involving crude, 10 kDa, and 5 kDa EPH. The IC50 values for the crude, 3 kDa 5 kDa, 10 kDa, EPH were determined to be 21.50 µg/ml, 6.50 µg/ml, 11.08 µg/ml and 16.84 µg/ml respectively. The results presented in this study indicate that the 3 kDa EPH had the greatest efficacy in inhibiting MCF-7 cells [109]. Hydrolysis shortens amino acid chains and exposes more hydrophobic amino acids, improving antioxidative and anti-proliferative activities. The hydrolytic degradation of EPH resulted in the increased exposure of hydrophobic amino acids, namely isoleucine, methionine asparagine, phenylalanine, valine, and glutamine in the N-terminal region. This phenomenon perhaps contributes to the suppression of MCF-7 cancer cell lines [110].

Table 1 Anti-proliferative activity of fish-derived bioactive peptides
Table 2 Antioxidative activity of fish-derived bioactive peptides

The utilization of a protein hydrolysate derived from tuna trimmings (Thunnas albacares) in conjunction with 5-fluorouracil (30 mg/kg) has been shown to improve the rate of tumour suppression, alleviate the mucosal damage caused by 5-FU in the intestines, and retain the typical structure of the villi and crypt walls in the mucosa of the small intestine [111]. The peptide with anti-cancerous action is opposed to human prostate cancer PC-3 cells derived from anchovy peptic hydrolysates. The peptide designated as YALPAH demonstrated the most apparent positive charge and displayed the most potent anti-proliferative action, as seen by an IC50 value of 8.1 mg/ml [112]. Ultrafiltered roe hydrolysates (URH) prepared from giant grouper can suppress the growth of oral cancer cell lines (Ca9-22 and CAL 27). URH also caused the oral cancer cells to endure apoptosis, which is a programmed cell death process. The characteristics of apoptosis induced by URH include changes in cell morphology, accretion of cells in the sub-G1 stage of the cell cycle and increased expression of annexin V and PI [113]. The PAH 2.5 fraction obtained using ultrafiltration with a cutoff of > 2.5 kDa, exhibited the highest level of anti-proliferative activity (IC50: 1.39 mg/mL). Tuna cooking liquid possesses significant potential as a protein source to produce anti-proliferative peptides targeting MCF-7 cells. Its treatment with the cancer cell line resulted in cell cycle arrest specifically in the S phase and triggered apoptosis in MCF-7 cells [100]. Fish-derived bioactive peptides inhibit apoptosis in oral cancer cells via a process involving the production of reactive oxygen species (ROS) and superoxide, as well as mitochondrial polarization. These findings suggest that fish-derived bioactive peptides have a promising compound to be used as an apoptosis-based anti-cancer therapy for oral cancer.

5.2 Anti-hypertensive fish bioactive peptides

Hypertension is a chronic medical illness characterized by persistently elevated blood pressure in the arteries. CVDs (cardiovascular diseases) accounted for 20.5 million deaths and over 500 million people are affected worldwide in 2021 [6]. The Renin-Angiotensin System (RAS) is crucial for maintaining blood flow and homeostasis by regulating salt balance [117]. Angiotensin Converting Enzyme (ACE) catalyzes a specific reaction: converting Angiotensin-I to Angiotensin-II, which regulates blood pressure through vasoconstriction and salt retention. Inactivation and reduction of ACE is considered a significant mode of treatment for hypertension [118, 119]. Mostly ACE inhibitors, angiotensin receptor blockers and anti-hypertensive drugs (lisinopril, benazepril, captopril chlorthalidone and hydrochlorothiazide) are available in the market to treat hypertension [120]. But those drugs cause side effects because of that natural marine-based compounds come into the study.

A novel ACE-inhibitory peptide (GPLGVP; IC50 = 105.8 µM) was identified from Alaska Pollack skin protein hydrolysates, showing promising potential for blood pressure regulation [75].

The highly effective ACEi protein hydrolysate (TMPH) from skipjack tuna muscle was created using alcalase under optimal conditions. This resulted in an ACEi activity of 72.71% at a concentration of 1.0 mg/mL. Following this, six novel ACEi peptides were isolated from TMPH using ultrafiltration and chromatography techniques. These peptides were identified as Ser-Pro (SP), Val-Asp-Arg-Tyr-Phe (VDRYF), Val-His-Gly-Val-Val (VHGVV), Tyr-Glu (YE), Phe-Glu-Met (FEM), and Phe-Trp-Arg-Val (FWRV). Notably, SP and VDRYF exhibited significant ACEi activity, with IC50 values of 0.06 ± 0.01 and 0.28 ± 0.03 mg/mL [82]. The production of bioactive peptides from shortfin scad fish waste. The study includes purification and characterization of the peptides, as well as molecular docking studies to understand their interactions with the ACE enzyme. The isolated peptide sequence and its biological activity are determined. The study reveals that the purified peptide (GVGPVPAA) acts as a competitive inhibitor of ACE and has strong potential as an antihypertensive agent [83]. The hydrolysate was protein seahorse protein fractionated by dialysis, Sephadex G-25 gel filtration chromatography, and reverse-phase high-performance liquid chromatography. After consecutive purification, a potent ACE-inhibiting peptide composed of 8 amino acids (Pro-Ala-Gly-Pro-Arg-Gly-Pro-Ala; MW: 721.39 Da; IC50 value: 7.90 μM) [89]. Sturgeon skin protein extract hydrolyzed by flavourzyme exhibited angiotensin converting enzyme (ACE) inhibitory activity. The sequences of peptides from flavourzyme hydrolysates were identified using high-performance liquid chromatography-tandem mass spectrometry. Gly-Pro-Pro-Gly-Ala-Asp-Gly-Gln-Ala-Gly-Ala-Lys (P6) displayed the highest ACE inhibitory activity (ACE IC50 = 3.77 mmol L−1). The molecular docking analysis revealed that ACE inhibition by P6 is mainly attributed to strong hydrogen bonds [93]. The lizard fish protein hydrolysates with the amino acid sequence Val-Tyr-Pro which has the potential to block ACE activity. The results of this study indicate that muscle protein derived from lizard fish exhibits the potential of ACE inhibitory peptides [121]. The study demonstrated the presence of ACE inhibitory peptides in the muscle protein of seaweed pipefish. A total of four fractions were isolated by alcalase hydrolysates (Fr3-I, Fr3-II, Fr3-III and Fr3-IV). Among these fractions, Fr3-II and Fr3-III exhibit the most significant ACE inhibitory activity. The peptides included in these fractions exhibit negligible cytotoxicity towards human lung fibroblast cell lines, indicating their potential use as components with anti-hypertensive properties in multifunctional food products [122].

The remarkable ACE inhibitory peptides are produced from various fish species like Alaska pollack [75], deep-water pink shrimp [90], shark [123], ribbon fish [124], hound [125], tuna [126], krill [127], boar [128], pacific cod [129], grass carp [130], sardinelle [131], bighead carp [132] and kawakawa [133] also have been studied in respect of the ACE inhibitory bioactive peptides (Table 3).

Table 3 ACE inhibitory activity of fish-derived bioactive peptides

The anti-hypertensive efficacy of lower molecular weight derived from enzymatically hydrolyzed fish protein fractionations was shown to be greater. The enhanced ACE inhibitory efficacy of peptides can be attributed to the inclusion of valine and arginine residues at the C-terminal. Consequently, the utilization of enzymes such as trypsin, which selectively cleave arginine may potentially facilitate the production of peptides with improved ACE inhibitory properties. The promise of bio-active peptides produced from fish as nutraceuticals and medicines lies in their efficacy in the prevention and treatment of hypertension.

5.3 Anti-diabetic fish bioactive peptides

Diabetes mellitus (DM) is a persistent metabolic disorder that impacts globally and its distinguished by elevated levels of blood glucose (hyperglycemia). Diabetes mellitus (DM) is commonly categorized into two primary classifications: type I diabetes (T1DM) and type II diabetes (T2DM) [134]. Insulin-dependent type I diabetes mellitus constitutes 10% of the total cases of diabetes mellitus, whereas non-insulin-dependent type II diabetes mellitus accounts for the remaining 90% of cases. Research findings indicate that the global prevalence of diabetes is projected to reach around 600 million cases by the year 2035 [135]. Hormone-like insulin is produced in the pancreas that regulates blood glucose levels. Insufficient insulin or insulin resistance results in abnormal blood glucose levels [136]. Fish-derived proteins and peptides have been shown to have anti-diabetic effects through various mechanisms, including stimulating glucagon-like peptide 1 (GLP-1) secretion, increasing insulin release, decline in dipeptidyl peptidase-IV (DPP-IV) activity, increasing glucose uptake, declining blood glucose concentrations, and upregulating glucose transporter type 4 (GLUT4) and peroxisome proliferator-activated receptor alpha (PPAR- α) [137,138,139] (Table 4). Peptides that inhibit DPP-IV are obtained from fish sources and typically consist of 3–15 amino acids. The most often occurring amino acid residues in these peptides are leucine, proline, valine, glycine, isoleucine, and phenylalanine [140, 141]. The protein hydrolysate was separated into four sub-fractions using RP-HPLC. The findings of the study indicated that the fourth sub-fraction (SF4) had the most potent inhibitory effect against DPP-IV, as evidenced by its IC50 value of 0.21 mg/mL [142].

Table 4 Anti-diabetic activity of fish-derived bioactive peptides

Antarctic krill protein contains two peptides (AP and IPA) that inhibit DPP-IV, an enzyme that breaks down incretin hormones. Incretin hormones stimulate insulin secretion and reduce glucagon secretion, which helps to improve glucose control [143]. The administration of marine peptides demonstrated enhanced glucose digestion and increased insulin sensitivity in rats with type 2 diabetes mellitus (T2DM). The observed benefits may be attributed to the peptides capacity to reduce the effects of inflammation and oxidative stress as well as enhance the expression of GLUT4 and PPAR-α, both of which play crucial roles in glucose absorption and metabolism [139]. The hydrolysate derived from silver carp by the application of neutrase for five hours exhibited the most pronounced inhibitory action against dipeptidyl peptidase IV (DPP-IV). This inhibitory effect was seen to be at its peak with an inhibition rate of 81% when the hydrolysate was present at a level of 5 mg/mL. The peptide WGDEHIPGSPYH had the highest potency as a DPP-IV inhibitor, displaying an uncompetitive inhibition mechanism with an IC50 value of 0.35 mM [140]. The sardine protein was subjected to enzymatic treatment using a mixture of three enzymes (subtilisin, trypsin and flavourzyme to produce hydrolysates with antidiabetic activity. This hydrolysate was subsequently purified by size exclusion chromatography. The highest dipeptidyl peptidase IV inhibitory activity was obtained with an IC50 of 1.83 ± 0.05 mg/ml with molecular weight in the range of 800 to 1400 Da [141]. Blue whiting protein hydrolysate was produced using alcalase and flavourzyme and its simulated gastrointestinal digestion (SGID) sample was assessed for antidiabetic potential. The results demonstrate that the blue whiting protein hydrolysate had significant metabolic effects relevant to glucose control [144]. The anti-obesity peptides were generated from fish water-soluble protein by enzymatic conditions and optimized with the aid of response surface methodology. The porcine pancreas lipase and α-amylase inhibitory rate could reach 53.04 ± 1.32% and 20.03 ± 0.89%, while predicted values were 54.63% ± 1.75%, 21.22% ± 0.70%, respectively [145]. The novel antidiabetic peptides were identified from the Chinese giant salamander (Andrias davidianus) protein hydrolysate. The peptides’ amino acid sequences were Cys-Ser-Ser-Val (MW = 393.99 Da), Tyr-Ser-Phe-Arg (MW = 570.99 Da), Ser-Ala-Ala-Pro (MW = 343.89 Da), Pro-Gly-Gly-Pro (MW = 325.99 Da) and Leu-Gly-Gly-Gly-Asn (MW = 415.99 Da) possessing α-amylase inhibitory activity IC50 of 13.76 × 103, 10.82 × 103, 4.46 × 103, 4.23 × 103, and 2.86 × 103 µg/mL, respectively; and for α-glucosidase with IC50 of 206.00, 162.00, 66.90, 63.50, and 42.93 µg/mL, respectively. The peptide LGGGN showed higher inhibition on both α-amylase and α-glucosidase and could be considered as a potential anti-diabetic inhibition [146]. The peptides produced from various fishery sources like salmon [147], boarfish [148] and tilapia [149] show good anti-diabetic potential.

Several laboratory and clinical investigations have provided data indicating that separated peptides might be incorporated as components in nutritional supplements or functional foods. These peptides can effectively block dipeptidyl peptidase-IV (DPP-IV), preventing the deterioration of glucagon-like peptide-1 (GLP-1) and maintaining insulin production. Furthermore, it is worth noting that most clinical trials are carried out using limited sample sizes, a factor that hinders the ability to make conclusive recommendations on the efficacy of these bioactive substances in the treatment and management of T2DM. Hence, it is imperative to conduct additional studies using larger sample sizes to provide further validation of the anti-diabetic ability.

6 Challenges and future perspectives

Fish peptides exhibit numerous biological functions, delivering them a promising bioactive constituent for the food, nutraceutical, and nutritional supplement sectors. The commercial use of bioactive peptides has been limited due to high costs. enzyme cost, long process, bitterness limiting oral consumption, lack of process optimization for bioactive properties, no control over the specific molecular weight of peptide, lack of food safety data, poor understanding between protein structure and bioactivity, absence of sufficient evidence showcasing the practical implementation of food and nutritional items, insufficiency of robust human data to substantiate claims regarding their health benefits and safety, no clear legal regulation or guidelines regarding the dosage and safety related to different age groups.

However, strategies and research are needed to industrialize the fish bioactive peptides. The high cost of production could be reduced by using economical raw materials like by-products, underutilized and trash fish. Systematic design of experiments approaches to optimize process parameters for best quality attributes. Several innovative and environmentally friendly methods, such as ultrafiltration membrane reactor, high-pressure hydrostatic processing and pulsed electric field-assisted enzymatic hydrolysis have been examined to enhance the overall functionality and effectiveness of the process. Peptides own a bitter test that could change the taste of the final product so suitable methods like debittering, encapsulation or masking approaches are used to tackle that problem. Utilizing in silico methods has been identified as a highly effective way to identify and synthesize specific bioactive peptides. Research on stability, bioavailability, absorption, distribution, metabolism, and excretion withdrew the process of action and safety. In conclusion, the present amount of clinical research on the prospective biological activities and health benefits offered by fish peptides is limited, suggesting more human investigations to gain a comprehensive understanding of the physiological significance of these peptides.

7 Conclusion

The fish processing industry generates huge, untapped nutritional-rich material that can be converted into protein hydrolysate. Fish-derived bioactive peptides provide significant applications in pharmaceuticals, nutraceuticals and functional food ingredients industries. Bioactivities of peptides derived from fish show cardioprotective, anti-hypertensive, anti-cancer, anti-diabetic, and anti-oxidative effects, suggesting their promising potential in the treatments and preventive care for NCD. Further research is required to develop pharmaceutical applications and more understanding of the mechanisms of bioavailability and bioaccessibility of fish-derived bioactive peptides.