Search

To improve the quality of life of diabetic patients, oral delivery of insulin would be better than subcutaneous injection, and the encapsulation of insulin for its oral delivery is a promising alternative one. In this study, we prepared an oral insulin delivery system using thiolated chitosan nanoparticles (TCNPs) loaded with insulin (Ins) and tested under in vitro and in vivo systems. TCNPs prepared from CS and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) at 4:1 ratio showed 220 ± 4 nm, 2.3 ± 1 mV, and 119 ± 4 μmol g−1 in their size, charge and sulfhydryl content, respectively. There was a sustained release of insulin from the TCNPs at pH 5.3. TCNPs treatment did not alter cell viability in vitro and oral administration of TCNPs reached over the tip of the microvilli near the intestinal mucosa in vivo. There were increased and decreased the levels of insulin and glucose in the blood, respectively when Ins-TCNPs were orally administered in the diabetes induced rats. Thus, our results suggested that the insulin stays significantly for a prolonged period to make bio-distribution and bioavailability due to its interaction with the mucus of the intestine, thus offering a better oral insulin delivery system for diabetic patients.

Antioxidant peptides protect biological macromolecules against radical damages. The use of these peptides was evaluated using free radicals scavenging assays [2,2-diphenyl-1 picrylhydrazyl (DPPH) and hydroxyl] with the help of UV-visible and electron spin resonance (ESR) spectroscopy methods. The Octopus aegina mantle protein were tested upon hydrolysis using gastrointestinal enzymes up to 12 h, where pepsin hydrolysate exhibited superior properties (DPPH: 44.39±0.67% and hydroxyl: 38.84±1.07%) compared with trypsin and α-chymotrypsin. Consequently, the antioxidant activity of the purified hydrolysate increased on a successive purification, and the peptide sequence was determined to be 368.9 Da with Gly-Glu-Tyr amino acids. Tripeptide exerted free radical scavenging efficiency in DNA damage, lipid peroxidation and cellular destruction (MCF7 cells) under stress condition. The results obtained with octopus antioxidant peptide suggested its role as an adjunct in food and pharmaceutical industries.

The aim was to drive the ACE-I inhibitory peptide from the dumped waste of O. woodmasoni muscle protein hydrolysate after 12 h of hydrolysis using thermolysin and pepsin. The degree of hydrolysis (DH) was observed till 12th hr and the maximum ACE-I inhibition activity was recorded in 2nd and 5th hr (73.51 ± 0.25% & 68.93 ± 0.23%) for thermolysin and pepsin respectively. Further, the higher active thermolysin hydrolysate was separated using ultrafiltration membrane unit and 10-3 kDa fraction showed chief ACE-I inhibition activity (IC50 value: 0.47 mg/mL). The active fraction was purified by consecutive chromatographic techniques using ion exchange chromatography (IEC) & gel filtration chromatography (GFC) using fast protein liquid chromatography (FPLC). Finally, the fraction TH1-A1 evaluated by ACE-I inhibition assay and showed 77.09 ± 2.18% inhibitions. The non-toxic peptide against MCF-7 cells was further characterized for functional properties at pH 2 to 10. The active purified fraction also exhibited antioxidant activity analyzed with various assays and found to have 5 amino acid sequence (Asn-Gly-Val-Ala-Ala) with molecular weight 431 Da through LC-MS/MS. In conclusion, the identified low molecular weight peptide from by catch O. woodmasoni waste has both ACE-I inhibition and antioxidant properties. Therefore, this peptide might be a better alternative nutraceutical and functional food after few more investigations.

Marine organisms provide an intriguing number of bioactive compounds. These bioactive compounds show immunomodulatory, antioxidant, anti-inflammatory and antimicrobial activities. Crabs rank third after shrimps and lobster as seafood delicacies and provide major health benefits when consumed due to presence of proteins, vitamins and unsaturated essential fatty acids. Due to their diverse biological activities, the peptides derived from marine sources may treat various diseases such as migraine, inflammatory bowel disease, rheumatoid arthritis etc. In this study the Crab Leg (CL) muscle was isolated and further hydrolysed using trypsin, alcalase and papain to produce enzymatic hydrolysates. The results obtained from degree of hydrolysis showed that the enzymes significantly cleave the proteins. Furthermore, the HPLC analysis for amino acid compositions of CL showed the sample contained both essential and non-essential amino acids where histidine (%) was highest. In vitro assays for anti-inflammatory activity like Albumin Denaturation (AD) and HRBC Membrane Stabilization (HMS) assay helped to determine the active hour hydrolysate showing the trypsin 3rd hr hydrolysate as having highest activity in CL (90.57 ± 0.95% and 49.94 ± 1.52%). This active hour hydrolysate was purified using gel filtration chromatography and the fractions were determined using AD and HMS assay which resolved fraction Ⅰ to be more active in CL. The low molecular weight peptide sequence was found to be L-G-L-G-A-A-V-L (713.456 Da) by using LC-MS/MS. Further, cell proliferation assay and ELISA were performed for the purified peptide to test the suppression of LPS-mediated induction of COX-2 in RAW264.7 macrophage cells.

In this current investigation, the antioxidant peptides were derived from marine Sepia brevimana mantle by trypsin, α-chymotrypsin and pepsin for 12 h hydrolysis. The active peptides were found in the hydrolysates of trypsin and α-chymotrypsin at the 7th hour and pepsin at the 8th hour. The highest activity was found in trypsin hydrolysate compared to others using various radical scavenging and metal ions transition assays, further the hydrophobic amino acids were observed in more quantity along with other amino acids. Active peptide was purified by consecutive chromatographic techniques and evaluated by DPPH (38.81 ± 1.07%) and reducing power assays (0.478 ± 0.03). The purified peptide exhibited significant inhibition for the linoleic acid auto-oxidation in the model system, protective effect on DNA damage due to hydroxyl radical induction and was non-toxic even at higher concentration. The mass and sequence of the peptide was found to be 679.5 Da and Ile/Leu-Asn-Ile/Leu-Cys-Cys-Asn, respectively. The current results suggested that cuttlefish peptide could be used as natural antioxidant in enhancing antioxidant properties of functional foods and in preventing oxidation reactions in food processing.

Peptide from croaker (Otolithes ruber) muscle protein hydrolysate was purified, characterized and evaluated for its in vitro and in vivo antioxidant activity. Results showed that purified peptide contained the amino acid sequence as Lys-Thr-Phe-Cys-Gly-Arg-His (861.6Da), which were expected to contribute to its antioxidant activities. This peptide efficiently quenched 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (84.5±1.2 and 62.4±2.9%), and successfully inhibits the lipid peroxidation and DNA damage and proven to be a potent antioxidant at different in vitro systems. It also improved the endogenous cellular antioxidant enzymes in Wistar rat by increasing the activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) after supplementation of the peptide (283.6±7.25, 4.3±0.78 and 28.42±1.97) compared to the negative control (196.4±5.65, 1.3±0.45 and 15.1±0.35). Therefore, croaker muscle peptide can increase an endurance capacity and facilitate recovery from oxidative stress.

In the present study, a peptide having high antioxidant properties was isolated from horse mackerel viscera protein, Magalaspis cordyla . In vitro gastrointestinal digestion was employed to obtain potential protein hydrolysate and was subjected to consecutive chromatographic methods using fast protein liquid chromatography (FPLC) connected to diethyl amino ethyl (DEAE) anion exchange column and Sephadex G-25 gel filtration column. The activity of the fractions was tested against DPPH and hydroxyl radicals and the isolated peptide showed 89.2 and 59.1 percentage of scavenging. The amino acid sequence of purified peptide was determined using ESI-MS/MS as Ala–Cys–Phe–Leu (518.5 Da), it exhibited high activity against polyunsaturated fatty acid (PUFA) peroxidation than that of natural antioxidant, α-tocopherol.