This study investigated the anti-inflammatory activity, molecular target and interaction mechanism of Ganoderma lingzhi-derived peptide Gln-Arg-Val-Cys-Glu (GLP4). The results showed that in LPS-induced inflammation in RAW264.7 cells, GLP4 significantly reduced the expression of COX-2, iNOS, TNF-α, IL-1β, and IL-6, and exhibited potent anti-inflammatory activities. GLP4 directly interacted with the target protein TBK1. Moreover, GLP4 mainly combined with the critical sites of TBK1 through hydrogen bonding and formed a stable complex. The binding affinity of GLP4 and TBK1 was 0.368 μmol/L. Further multispectral experiments showed that the interaction of GLP4 with TBK1 altered its secondary structure. Notably, GLP4 intervention directly inhibited the phosphorylation activity of TBK1 and affected the activation of NF-κB. Our study reported the inflammation-modulating ability of Ganoderma lingzhi mycelial peptides for the first time, providing valuable insights into the natural anti-inflammatory activity of functional foods or nutritional supplements.

Ganoderma lingzhi is a new species of the prize medicinal mushroom Ganoderma (Agaricomycetes). Using angiotensin Ⅰ-converting enzyme (ACE) as a target, a tripeptide Ser-Tyr-Pro (SYP) was discovered with preponderant ACE inhibitory activity with an 50% inhibiting concentration (IC₅₀) value of 62.50 μg/mL attribute to the formed salt bridge and hydrogen bonds between SYP and ACE. SYP even maintained superior bioactivity after intestinal digestion, and exerted no cytotoxicity, but presented incomplete bioavailability in blood of spontaneous hypertensive rats (SHRs). Furthermore, it performed antihypertensive effect in vivo by inhibiting the influx of Ca²⁺ through activating endothelial NO synthase (eNOS)/NO/guanosine 3’,5’-cyclic monophosphate (cGMP) pathway, accompanied by attenuating angiotensin Ⅱ (Ang Ⅱ)/NADPH oxidase (NOX)/reactive oxygen species (ROS) pathway. This work not only discoverers a novel pharmacological ingredient from medicinal mushroom G. lingzhi for hypertension therapy, but also provides an insight into molecular mechanism of the ACE inhibitory peptide (ACEIP) on lowering blood pressure.

3,4-Dihydroxy-2,2-dimethyl-chroman derivatives have diverse physiological properties. A polyketone (3S,4S)-3,4-Dihydroxy-6-methoxy-2,2-dimethylchromom (3S,4S-DMD) with antibacterial activity was isolated from the solid culture of rare edible fungus Panus lecomtei. However, the yield of 3S,4S-DMD in solid culture of P. lecomtei is very low and the production period are too long. In this work, efficient accumulation of 3S,4S-DMD in P. lecomtei by submerged fermentation is studied. The key fermentation factors of P. lecomtei for 3S,4S-DMD production were optimised by single-factor experiment successively, and then a Box-Behnken design (BBD) experiment was carried out to further enhance 3S,4S-DMD production. A maximum 3S,4S-DMD yield of 196.3 mg/L was obtained at 25.78 g/L glucose, 1.67 g/L MgSO₄ · 7H₂O, 40℃ and 197 r/min, respectively, which increased by 1.3-fold in comparison with that in the non-optimised fermentation conditions. Furthermore, an enhanced yield of 3S,4S-DMD (261.6 mg/L) was obtained in 5-L agitated fermenter. The 3S,4S-DMD productivity in flask and fermenter reached to 7.26 and 8.07 mg/g per day, respectively, which considerably increased by over 121-fold in comparison with that in the solid fermentation (0.06 mg/g per day). This study presents a potential method for the production of 3S,4S-DMD by submerged fermentation.