## 3 Results and Discussion
### In Silico Analysis of the Isolated Major Protein from 'Senorita' Banana Extracts  
UniProt KB [20] Protein Search query returned more than 2000 _Musa acuminata_ proteins which have a MW of 15 kDa, the approximate MW of the major protein. Some of the proteins returned in the query includes profilin, histone, thioredoxin, ferredoxin, ribosomal proteins, lectin and various enzymes such as kinases, lysates and chitinase. Lectin was used as the putative protein for its sugar binding property and is found in both inter- and intracellular space allowing them to be easily extracted compared to other proteins in the search query which can be found in the cellular organelles requiring a complicated extraction procedure. A study by [PERSON] [27] showed that lectin is easily extracted from white kidney beans by using 0.15 M NaCl. Figure 3 shows the lectin protein sequence after hydrolysis using the enzymes pepsin, trypsin, chymotrypsin, and thermolysin obtained through BIOPEP-UWM [21] protein analyzer. The highlighted peptide fragments are known to exhibit ACE inhibitory activity and/or antioxidant activity. Determination of the Percent (%) Angiotensin Converting Enzyme (ACE) Inhibition as a Basis of Antihypertensive Activity  
The results in Table 2 confirmed that the sample extracts have ACE inhibitory activity even though some values were small. The percent ACE inhibition of the samples were all significantly different to that of captopril (standard), even though the concentration of the drug was leveled to the concentration of the samples (50 mg/mL). A study by [PERSON] et al. [28] showed that the activity of ACE inhibitory compounds depends on the dosage and identity of the compound. Hence, it could be that the low concentration of the samples during the testing have led to the observed low activities. Figure 3: Representation of the cleavage sites (-) of pepsin, trypsin, chymotrypsin and thermolysin in the lectin protein sequence with the peptides highlighted are known to exhibit ACE inhibitory activity and/or antioxidant activity. Yellow highlight for ACE inhibitor peptides and blue highlight for both ACE inhibitor and antioxidant peptides. Among the samples tested, the undigested crude protein extract showed the highest activity with 85.20% while the remaining samples have roughly 10% to 40%. The undigested crude extract was composed of various proteins in their native conformation as well as traces of other easily extractable compounds such as polyphenols, which could account for the observed high activity. For instance, a study by [PERSON] et al. [29] and [PERSON] et al. [30], showed that crude protein extracts from various mushroom samples inhibited ACE by up to 90% depending on the kind of mushroom and extraction methods employed. On the other hand, a study conducted by [PERSON] [31] showed that flavonoids, a subclass of polyphenols, extracted from fruit tissues can inhibit ACE with results dependent on the sugar moiety attached to the flavonoid ring. Other documented bioactive compounds that can inhibit ACE include polysaccharides, sterols, saponins, fiber, vitamins C and E, and other minerals. Statistical analysis on the crude sample at different digestion hours showed that there was a significant decrease in the activity of undigested crude sample after the three-hour digestion followed by a subsequent increase in the activity until the 24-h digestion period (Figure 4). This implies that the initial hydrolysis of the proteins from the crude extract led to denaturation and loss of the active native conformation, resulting to the observed decrease in activity. On the other hand, the observed increase in activity as the digestion period is increased could mean that the precursor protein(s) were continuously broken down to bioactive peptides inhibiting ACE. However, since the activities of 12-h and 24-h digests are not significantly different, the number of bioactive peptides released after 12 h of digestion did not significantly increase.