Antihypertensive, Antioxidative, and Hypocholesterolemic Activities of Bioactive Peptides From Bamboo (Bambusa blumeana) Shoots

The bioactive peptides derived from proteins of bamboo (Bambusa blumeana) shoots were isolated and characterized in this study. In silico analysis revealed 24 proteins in B. blumeana, of which upon simulated peptide cutting resulted in 8 dipeptides exhibiting lone ACE-inhibition activity and 2 dipeptides displaying both ACE-inhibitory and antioxidative capabilities. Isolation of proteins from unboiled bamboo (UBS) and boiled bamboo (BBS) shoots was done using 50 mM phosphate buffer pH 7.4. The amount of proteins obtained using Bradford assay was estimated to be 0.876 +/- 0.015 mg mL(-1) and 0.808 +/- 0.020 mg mL(-1) for UBS and BBS, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of crude UBS (CUBS) and crude BBS (CBBS) revealed four bands wherein the major band corresponds to an approximate molecular weight of 22.8465 +/- 0.3741 kDa. Enzymatic digestion using pepsin, thermolysin, chymotrypsin, and trypsin for 3, 6, 12, and 24 hr was performed as well. As supported by the data from densitometric analysis, results showed that digestion of the major protein of the bamboo shoots was successful upon further SDS-PAGE. Performing antihypertensive assay showed that the 3-hr and 6-hr digests have ACE-inhibitory activities, with the 6-hr digest of UBS having the highest activity of 9.6200 +/- 1.9875%. Furthermore, results of the antioxidative assay revealed that the 3-hr, 6-hr, and 12-hr digests exhibited DPPH radical scavenging activities, with the 12-hr hydrolysate of UBS showing the most pronounced activity at 46.898 +/- 1.089%. Lastly, the hypocholesterolemic assay showed that the crude protein and the 3-hr and 24-hr digests have cholesterol-binding capacities, of which the maximum capacity of 57.939 +/- 0.748% was recorded by the 24-hr digest of UBS. The shoots of B. blumeana were then found to be promising in terms of their antioxidative and hypocholesterolemic activities.