5.1 Anticancer Peptides
Cancer accounts for about one-eighth of deaths worldwide and has now become
one of the leading causes of mortality. Fortunately, rapid progress in the successful
treatment of some cancers, formerly fatal, has changed the situation of cancer
patients to survivors with chronic diseases due to the development of successful
therapy and using anticancer drugs. The development of new medical therapies
based on bioactive peptides showed to possess and bring several significant benefits, including low cytotoxicity, strong specificity, ability to penetrate tumor cells,
small size, and easy structural modification [85]. Some whey proteins have played
notable roles in cancer therapy by exhibiting activities against cancer cells mainly
through cytoplasmic membrane disturbance and apoptosis induction. For example,
the multimeric form of a-LA protein accelerates apoptotic processes in the transformed and immature cells while protecting mature epithelial cells. The b-LG
protein showed to have the ability to protect against cancer development in an
animal model when administered orally. Both BSA and bovine lactoferrin
(BLF) prevented the growth of a human cell line responsible for breast cancer, but
they are dependent on dosage [86].
Additionally, some fragments released after hydrolysis of whey proteins showed
also to play an important role in cancer therapy. One example is the fragment
FKCRRWQWRMKKLGAPSITCVRRAF f(17–41) released from bovine lactoferrin, called Lactoferricin. This fragment exhibited cytotoxic activity in several
human and rat malignant cell lines, including fibrosarcoma, leukemia, different
cancer cells, and neuroblastoma. Additionally, these peptides are at concentrations
that do not substantially affect the viability of normal fibroblasts, lymphocytes,
epithelial cells, endothelial cells, or erythrocytes [87].
Chen et al. [88] reported that anticancer peptides have a sequence length of 5–30
amino acids with 40–60% content in hydrophobic residues, a specific cationic
charge, and a secondary structure in the a-helix form, in particular with a twist on
its helical axis. Gabernet et al. [89] found a high percentage of Ala, Gly, Ile, Lys,
Arg, and Leu amino acids, while amino acid Lys is responsible for the positive
charge.
Chalamaiah et al. [90] recently reviewed the anticancer peptides derived from
milk and whey proteins and their related amino acid composition.
5.2 Antidiabetic Peptides
Gaudel et al. [91] reported positive effects with oral administration of whey protein
hydrolysates that improved blood glucose clearance, reduced hyperinsulinemia, and
restoration of the ability of pancreatic islet to segregate insulin in response to the
glucose level in an animal model of obese mice. Additionally, Nongonierma et al.
[92] also observed that whey protein hydrolysates with high concentrations of free
amino acids and hydrophilic peptides were responsible for increasing the insulinotropic response of BRIN-BD11 cells.
492
A. F. A. Salvado et al.
Cancer accounts for about one-eighth of deaths worldwide and has now become
one of the leading causes of mortality. Fortunately, rapid progress in the successful
treatment of some cancers, formerly fatal, has changed the situation of cancer
patients to survivors with chronic diseases due to the development of successful
therapy and using anticancer drugs. The development of new medical therapies
based on bioactive peptides showed to possess and bring several significant benefits, including low cytotoxicity, strong specificity, ability to penetrate tumor cells,
small size, and easy structural modification [85]. Some whey proteins have played
notable roles in cancer therapy by exhibiting activities against cancer cells mainly
through cytoplasmic membrane disturbance and apoptosis induction. For example,
the multimeric form of a-LA protein accelerates apoptotic processes in the transformed and immature cells while protecting mature epithelial cells. The b-LG
protein showed to have the ability to protect against cancer development in an
animal model when administered orally. Both BSA and bovine lactoferrin
(BLF) prevented the growth of a human cell line responsible for breast cancer, but
they are dependent on dosage [86].
Additionally, some fragments released after hydrolysis of whey proteins showed
also to play an important role in cancer therapy. One example is the fragment
FKCRRWQWRMKKLGAPSITCVRRAF f(17–41) released from bovine lactoferrin, called Lactoferricin. This fragment exhibited cytotoxic activity in several
human and rat malignant cell lines, including fibrosarcoma, leukemia, different
cancer cells, and neuroblastoma. Additionally, these peptides are at concentrations
that do not substantially affect the viability of normal fibroblasts, lymphocytes,
epithelial cells, endothelial cells, or erythrocytes [87].
Chen et al. [88] reported that anticancer peptides have a sequence length of 5–30
amino acids with 40–60% content in hydrophobic residues, a specific cationic
charge, and a secondary structure in the a-helix form, in particular with a twist on
its helical axis. Gabernet et al. [89] found a high percentage of Ala, Gly, Ile, Lys,
Arg, and Leu amino acids, while amino acid Lys is responsible for the positive
charge.
Chalamaiah et al. [90] recently reviewed the anticancer peptides derived from
milk and whey proteins and their related amino acid composition.
5.2 Antidiabetic Peptides
Gaudel et al. [91] reported positive effects with oral administration of whey protein
hydrolysates that improved blood glucose clearance, reduced hyperinsulinemia, and
restoration of the ability of pancreatic islet to segregate insulin in response to the
glucose level in an animal model of obese mice. Additionally, Nongonierma et al.
[92] also observed that whey protein hydrolysates with high concentrations of free
amino acids and hydrophilic peptides were responsible for increasing the insulinotropic response of BRIN-BD11 cells.
492
A. F. A. Salvado et al.