Discovery of calcium-binding peptides derived from defatted lemon basil seeds with enhanced calcium uptake in human intestinal epithelial cells, Caco-2.

It is anticipated that calcium-chelating peptides may serve to enhance the absorption of calcium. This research examined defatted lemon basil seeds (DLBS) which had been treated with Alcalase under optimized parameters for the degree of hydrolysis for proteolysis, discovering that the activity for calcium-binding in a competitive condition with phosphate ion was 60.39 ± 1.545%. The purification of the hydrolysates was performed via ultrafiltration along with reversed-phase high performance liquid chromatography (RP-HPLC). Determination of the purified peptide amino acid sequence was confirmed for both peptides and reported as Ala-Phe-Asn-Arg-Ala-Lys-Ser-Lys-Ala-Leu-Asn-Glu-Asn (AFNRAKSKALNEN; Basil-1), and Tyr-Asp-Ser-Ser-Gly-Gly-Pro-Thr-Pro-Trp-Leu-Ser-Pro-Tyr (YDSSGGPTPWLSPY; Basil-2). The respective activities for calcium-binding were 38.62 ± 1.33%, and 42.19 ± 2.27%. Fluorescence spectroscopy, and fourier transform infrared spectroscopy were employed in order to assess the chelating mechanism between calcium and the peptides. It was found that the calcium ions took place through the activity of the amino nitrogen atoms and the oxygen atoms on the carboxyl group. Moreover, both of these peptides served to improve calcium transport and absorption in Caco-2 cell monolayers, depending on the concentration involved. It was revealed that the peptide-calcium complexes offered an increased calcium absorption percentage when compared to free calcium at similar concentrations. It might be concluded that the peptide within the peptide-calcium complex can promote calcium absorption through both active and passive transport pathways by increasing calcium concentration and promoting cell membrane interaction. Accordingly, DLBS protein can be considered a strong potential source of protein which can be used to produce calcium-binding peptides and might therefore play a role in the production of nutraceutical foods as a bioactive ingredient.

ACE inhibitory peptides derived from de-fatted lemon basil seeds: optimization, purification, identification, structure-activity relationship and molecular docking analysis.

The oil processing industry generates significant quantities of lemon basil seed residue which is not currently used to any significant extent. However, this by-product has important potential as a source of bioactive peptides which may play a role as ingredients in functional foods. This study therefore sought to optimize the preparation techniques used to obtain the necessary protein hydrolysate from de-fatted lemon basil seeds (DLBS), and subsequently to examine the ACE inhibitory capabilities of the resulting hydrolysate. Response Surface Methodology (RSM) was used for the hydrolysis of DLBS by Alcalase®, with observation of the resulting ACE inhibitory activity and degree of hydrolysis (DH). The optimum conditions were 55 °C and 103 minutes with a ratio of enzyme to substrate of 7.0% w/v. The hydrolysate was fractionated by ultrafiltration and purified through RP-HPLC. The results reveal that the F2 sub-fraction demonstrated the highest ACE inhibitory activity. The amino acid sequence of this peak was identified by mass spectrometry as LGRNLPPI and GPAGPAGL with a molecular weight of 879.06 and 639.347 Dalton, respectively. These peptides were classified as non-toxic and bitter peptides. For the synthesized version of these peptides, the ACE inhibitory activity values, measured by IC50, were 0.124 ± 0.02 mM and 0.013 ± 0.001 mM, respectively. Analysis of the Lineweaver-Burk plot confirmed that these peptides served as non-competitive ones. The study of molecular docking showed that the ACE inhibitory behavior of both purified peptides was mainly due to the interactions of the hydrogen bonds between the peptides and ACE. It is therefore suggested that DLBS may be a useful raw material allowing the production of antihypertensive peptides which can offer therapeutic and commercial benefits as an ingredient in functional foods.

Antifungal and antiproliferative activities of lectin from the rhizomes of Curcuma amarissima Roscoe.

A lectin was purified from the rhizomes of Curcuma amarissima Roscoe by aqueous extraction, fractionation with 80% saturated ammonium sulfate, and a combination of affinity and gel chromatography on ConA Sepharose and Superdex G-75, respectively. The molecular mass of the purified lectin was 32.4 kDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The lectin showed no significant specificity in its ability to hemagglutinate erythrocytes from human blood groups (A, B, AB, and O), but for other animals, it only agglutinated rabbit and rat, and not mouse, guinea pig, goose, and sheep erythrocytes. The lectin was stable at temperatures below 40 degrees C, but the hemagglutinating activity halved when it was heated to 45-85 degrees C and was completely lost at 95 degrees C. The hemagglutinating activity was more stable at 80 degrees C than at 70 degrees C and was rapidly inactivated at 90 degrees C. It showed a maximum hemagglutination activity within the pH range of 8.0-11.0. The deduced amino acid sequence of an internal tryptic peptide sequence of this purified lectin showed sequence similarity (homology) to other members of the leucoagglutinating phytohemagglutinin precursor family, whilst the complete lectin inhibited the in vitro growth of three plant pathogenic fungi, Fusarium oxysporum, Exserohilum turicicum, and Colectrotrichum cassiicola, at a concentration of 17.5 to 35 microg, and showed in vitro cytotoxicity against the BT474 breast cancer cell line with an IC(50) of approximately 21.2 microg.