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This paper reports the design, synthesis, and antibacterial activity study of pleuromutilin derivatives with 2‐methyl‐4‐nitroaniline and 2‐methoxy‐4‐nitroaniline side chains at the C22 position. The structures of the new compounds were characterized by 1H‐NMR, 13C‐NMR and HRMS. The inhibitory activity of the compounds against MSSA, pyogeniccoccus, streptococcus, and MRSA strains was determined using the micro broth dilution method. The results showed that the compounds exhibited certain activity against Gram‐positive bacteria, among which compounds A8a, A8b, A8c, A8d, and A7 demonstrated superior antibacterial activity against MSSA, MRSA, and pyogeniccoccus compared to tiamulin, although the derivatives showed lower antibacterial activity against streptococcus compared to the control drug. Based on the favorable in vitro activity of A8c, the time‐kill kinetics against MRSA were evaluated, revealing that compound A8c could inhibit bacterial proliferation in a concentration‐dependent manner. [ABSTRACT FROM AUTHOR]

A series of novel pleuromutilin derivatives were designed and synthesized based on the twin drugs theory. Piperazinyl and thioether were used as the linkage to connect the pleuromutilin nuclear and sulfonamide to improve the biological activity and water solubility of derivatives. The in vitro antibacterial activities against drug-sensitive and drug-resistance bacteria were evaluated by agar dilution method. Most of the 25 compounds displayed excellent antibacterial activities against drug-sensitive bacteria, particularly, five compounds (9, 10, 11, 14a and 14b) exerted the excellent antibacterial activities against drug-resistance bacteria. [ABSTRACT FROM AUTHOR]

We described the design, synthesis and antimicrobial activities of novel pleuromutilin derivatives with substituted piperazine substrate. Minimum inhibitory concentration (MIC) was used to evaluate the activity of the derivatives against six bacteria in vitro, and compound 8 was potent against Staphylococcus aureus and Staphylococcus epidermidis with the MIC value of 0.0625 μg/ml. 10a and 10 b showed similar activity to positive control drugs (tiamulin, erythromycin) against S. aureus with the MIC value of 0.125 μg/ml. The binding mode of compound 8 and tiamulin to the ribosome pocket showed the correlation between binding parameters and the antibacterial activity, and more bonds and stronger combination could effectively enhance the activity of compounds. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the efficacy and safety of lignin peroxidase (LIP) as a skin-lightening agent in patients with melasma. A self-controlled clinical study was performed in 31 women who had melasma on both sides of the face. This study involved 8 weeks of a full-face product treatment. The skin color was measured at days 0, 7, 28 and 56 using a chromameter on the forehead and cheeks. Standardized digital photographic images of each side of the face of all subjects were captured by a complexion analysis system. Clinical scores of the pigmentation were determined by two dermatologists. After using the LIP whitening lotion for 7 days, the luminance (L*) values of the melasma and the normal skin were significantly increased from baseline. The L* values continued to increase at days 28 and 56. The melasma area severity index (MASI) score was statistically decreased after 28 days of treatment. No treatment-related adverse events were observed. LIP whitening lotion was able to eliminate the skin pigmentation after 7 days of treatment, and provides a completely innovative approach to rapid skin lightening. The LIP whitening lotion exhibited good compatibility and was well tolerated.