The lingzhi mushroom (Ganoderma lucidum) is well known for its medicinal properties and has long played a role in
traditional oriental medicine due to its health-giving benefits and potential to extend life expectancy. The mushroom contains a number of highly bioactive compounds and can also act as an excellent source of
protein. This research investigated the
peptides obtained from the
protein hydrolysates of lingzhi mushrooms to assess their
free radical scavenging abilities. These
peptides were acquired via different
proteases (
Alcalase,
Neutrase,
papain, and
pepsin-
pancreatin) and were tested at a range of different concentrations (1.0%, 2.5%, and 5.0% w/v). The highest levels of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic
acid (
ABTS),
2,2-diphenyl-1-picrylhydrazyl (DPPH) and
nitric oxide (NO) radical scavenging activities were presented by lingzhi mushroom hydrolysate using 2.5% (w/v)
pepsin-
pancreatin after 6 h of digestion. The hydrolysate was then fractionated using 10, 5, 3, and 0.65 kDa molecular weight cut-off membranes. The results showed that the MW 0.65 kDa fraction had the highest level of
free radical scavenging activity. Further analysis of this MW 0.65 kDa fraction began with another RP-HPLC fractionation technique to obtain three further sub-fractions. De novo
peptide sequencing using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS/MS) was chosen as the optimum method for studying the F3 sub-fraction. DRVSIYGWG and ALLSISSF were discovered as new
peptides with different
antioxidant properties.
Adenocarcinoma colon (Caco-2) cells showed the
antioxidant action of these synthesized
peptides. This activity was linked to
peptide concentration. The
peptides and their pure synthetic counterparts were found to reduce NO generation by RAW 264.7 macrophages without causing cytotoxicity. The results of gene expression reveal that the DRVSIYGWG and ALLSISSF
peptides were able to cut the expression of the proinflammatory
cytokine genes iNOS,
IL-6, TNF-α, and COX-2 in the context of RAW 264.7 macrophages.