1. Antibacterial effect: USNIC ACID can effectively inhibit the growth of Gram-positive bacteria such as Staphylococcus aureus, MRSA, Bacillus acnes, Corynebacterium, and can inhibit the growth of Pyrosporidium, directly killing Staphylococcus aureus. cells, and hinder the signal transduction pathway of Pseudomonas aeruginosa, suggesting that Usnea chinensis extract and usnic acid can be used to treat acne, rosacea, seborrheic dermatitis and other related skin diseases; in addition, USNIC ACID has the effect of eliminating sa drug-resistant plasmids. The elimination rate was 52% within 24 hours, and the duration of action was extended to 48 hours, and the elimination rate was up to 14.6%. It may be used for clinical treatment of drug-resistant sa infection.
2. Antiviral effect: Studies have shown that USNIC ACID has the potential to inhibit the proliferation of mouse polyoma virus, mainly by inhibiting the formation of messenger RNA, thereby indirectly inhibiting DNA replication. Usnic acid in Usnea longiflora has inhibitory activity against Epstein-barrvirus (EBV), of which (+)-usnic acid showed the highest inhibitory activity (ED501.0 μg/mL), while ( The inhibitory activity of -)-usnic acid was weak (ED505.0μg/mL).
3. Insecticidal effect: (+)-USNIC ACID has the activity of killing the promastigote of Leishmania donovani (Kala-azar), and the in vitro activity concentration of (+)-usnic acid is 25μg/mL. The minimum effective concentration of S-(-) usnic acid to kill Trichomonas in vitro was 0.4 mg/mL, and there was no significant difference in the in vitro killing effects of usnic acid at or above 0.4 mg/mL and the same concentration of metronidazole. Usnic acid has a growth inhibitory effect on trypanosome larvae within 5-30 μg/mL, and usnic acid can also significantly reduce the amount of trypanosomes in the blood, with 40 or 80 μg/mL USNIC ACID acting on infected macrophages cells, which can lead to the disintegration of trypanosome mitochondria and Golgi apparatus, and the cytoplasm becomes vacuolated, but it has no effect on host cells.
4. Anti-tumor effect: USNIC ACID has anti-wild-type P53 breast cancer cell line MCF7, non-functional P53 breast cancer cell line MDA-MB-231, lung cancer cell line H1299 and various cancer cell lines L1210, 3LL, DU145, MCF7 , K-562 and U251 activity, but does not cause damage to the DNA of normal cells, so it is expected to be developed into a new generation of anticancer drugs. The inhibitory effect of usnic acid extracted from the fungus Usnea on the proliferation of prostate cancer PC-3M cells in vitro was studied. The cell growth inhibition experiment showed that the maximum inhibition rate could reach more than 80%, and the biological effect was inhibited in a dose-dependent manner. relationship, indicating that usnic acid has an inhibitory effect on PC-3M cells cultured in vitro, slows down the proliferation of tumor cells, and has an obvious anti-tumor effect. But usnic acid had no inhibitory effect on 12(S)-LOX cultured with human platelets in vitro. The water solubility of usnic acid is poor. We used 10% HP-β-CD as a solubilizer to investigate the effect on three human malignant cell lines under the condition of pH 7.4. -70-fold increased solubility in CD with EC50s of 2.9 μg/mL, 4.3 μg/mL and 8.2 μg/mL for T-47D, Panc-1 and PC-3 cells, respectively.
5. Anti-inflammatory activity: The anti-inflammatory activity of usnic acid was studied using the rat foot swelling test (acute inflammation) and the rat cotton ball granuloma test (chronic inflammation), and ibuprofen was used as the positive control drug. For acute inflammation, the anti-inflammatory effect of ibuprofen is better than that of usnic acid at the same dose as ibuprofen (oral 100 mg/kg); for chronic inflammation, the anti-inflammatory effects of the two are equivalent, and there is a significant difference compared with the control group , it is speculated that the anti-inflammatory mechanism of pine acid is related to the inhibition of prostaglandin synthesis.
6. Other activities: To study the effect of sodium usneate on promoting skin wound healing, the overall experiment shows that external application of usnic acid sodium can accelerate the repair of experimental large skin damage, but at 0.5 ~ 8μg/mL, it can promote the proliferation of L929 fibroblasts. No promotion. In addition, the effect of sodium usnate on fibroblasts and its mechanism of promoting wound healing were also investigated. The results showed that sodium usnate could promote fibroblasts to secrete TGF-1 and EGF, and with the increase of drug concentration The enhancement can produce chemotactic effects on repair cells and inflammatory cells, promote repair cell migration and extracellular matrix deposition, and promote wound healing. In addition, experimental studies have shown that usnic acid has a good gastroprotective effect on indomethacin-induced gastric ulcer model in rats. Compared with the model group, it can significantly increase the levels of SOD, GSH and GPx, reduce the level of LPO, and increase the level of SOD, GSH and GPx in rats. cNOS, reduce iNOS. In terms of anti-radiation, the absorption of lichen secondary metabolites in the UV region was studied. The results showed that usnic acid mainly had absorption in the UV-B region and was relatively stable to light. And the photolysis product of usnic acid still has UV absorption, suggesting that USNIC ACID is a very potential natural sunscreen that can be used in cosmetics such as sunscreen.