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Objectives: This study aimed to investigate whether the plant species Stachys byzantina produces bioactives with the potential to delay the skin ageing process and treat hyperpigmentation conditions., Methods: The antioxidant action was assessed by 2,2-diphenyl-1-picrylhydrazylradical scavenging, Griess reaction, oxygen radical absorption capacity, and β-carotene bleaching assays. Inhibitory activities for tyrosinase, hyaluronidase, and elastase enzymes were tested. The antiglycation activity, the sun protection factor (SPF), and the toxicity to skin cells by MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay were also evaluated., Key Findings: The ethanolic extract of S. byzantina aerial parts and all fractions obtained by solvent partition inhibited the tyrosinase enzyme at different levels. The dichloromethane fraction (DF) demonstrated the highest inhibition (IC50 = 63.5 ± 10.9 µg/ml). DF also inhibited the hyaluronidase enzyme with IC50 = 369 ± 11.64 μg/ml and elastase by 40% at 500 μg/ml. This fraction showed prominent antioxidant and antiglycation activities, high SPF, and no cytotoxicity at concentrations lower than 50 μg/ml. The phenolic and flavonoid contents were 116.30 ± 6.7 (mgTAE/g) and 66.38 ± 13.5 (mgQE/g), respectively. Chlorogenic acid (23.54 ± 2.46 mg/g) and verbascoside (203.97 ± 19.8 mg/g) were identified and quantified., Conclusions: Stachys byzantina is a potential source of cosmetic and therapeutic ingredients to reduce hyperpigmentation and the impacts caused by free radicals, advanced glycation end products, and sun radiation in skin ageing., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Stachys byzantina is a plant widely cultivated for food and medicinal purposes. Stachys species have been reported as anti-inflammatory, antibacterial, anxiolytic, and antinephritic agents. This study aimed to evaluate the anti-inflammatory potential of the ethanolic extract (EE) from the aerial parts of S. byzantina and its most promising fraction in models of acute and chronic inflammation, including a psoriasis-like mouse model. The EE was fractionated into hexane (HF), dichloromethane (DF), ethyl acetate (AF), and hydroalcoholic (HD) fractions. Screening for anti-inflammatory activity based on nitric oxide inhibition (IC 50 μg/mL: HF 24.29 ± 5.87, EE 176.45 ± 18.65), hydroxyl radical scavenging (HF 3.89 ± 0.61, EE 6.38 ± 2.25), β-carotene/linoleic acid assay (HF 10.13 ± 3.81, EE 25.64 ± 2.12), and ORAC identified HF as the most active fraction. Topical application of HF effectively reduced croton oil- and phenol-induced ear edema in mice, with no statistical difference to the reference drugs. A formulation containing HF showed significant activity in the imiquimod-induced psoriasis model, reducing pro-inflammatory cytokines and nitric oxide production in macrophages, with no cytotoxicity to skin cells. Phytochemical analysis of HF revealed the presence of terpenes, steroids (491.68 ± 4.75 mg/g), phenols (34.30 ± 4.96 mg/g), flavonoids (151.77 ± 6.66 mg/g), and α-tocopherol, which was identified and quantified by HPLC-UV analysis (10.56 ± 0.97 mg/g of HF). These findings highlight the therapeutic potential of S. byzantina for skin inflammation, particularly contact dermatitis and psoriasis, encouraging further studies, including in human volunteers., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Antimicrobial peptides are biologically active molecules produced by a wide range of organisms as an essential component of the innate immune response. They have recently attracted great interest, since they have antimicrobial activity against a broad spectrum of microorganisms. VmCT1 is a cationic peptide from the venom of Vaejovis mexicanus smithi scorpions, which presents antibacterial activity and tends to helical structures. Its analogs were synthesized, characterized and the conformational studies were performed by circular dichroism. The peptides were designed to verify if the single and double substitutions proposed at the hydrophilic and hydrophobic portions of the amphipathic structure would alter antimicrobial activity against Gram-negative and Gram-positive bacteria, yeast and filamentous fungus, besides the hemolytic activity in human erythrocytes. Total charge of the peptides were modified from +2 to +3 by the introduction of a Lysine residue in the hydrophilic face of the amphiphilic helical structure leading to enhanced antimicrobial activity. [K] 11 -VmCT1-NH 2 presented the lower MIC value against the microorganisms (from 0.39 to 6.25 μmol L -1 ), however it showed higher hemolytic activity. The other Lysine-substituted analogs presented also lower MIC values ranging from 0.39 to 25 μmol L -1 for the microorganisms assessed. The circular dichroism spectra analyses suggest that the Lysine-substituted analogs tend to adopt helical structures in trifluoroethanol solution and vesicles (f H : 0.43-1), however they were coiled in water. Alanine substitution by a Glutamic acid residue in the hydrophilic face promotes the increase of polar angle in [E] 4 -VmCT1-NH 2 analog, which was important to led lower hemolytic activity (MHC value = 25 μmol L -1 ). [W] 9 -VmCT1-NH 2 and [E] 4 [W] 9 -VmCT1-NH 2 were designed to favors hydrophobic interactions by the introduction of Tryptophan residue. [W] 9 -VmCT1-NH 2 presented MIC values lower or similar than the model molecule in the most of microorganisms tested. These results provided information about the structure-activity relationship and showed the influence of physicochemical parameters on antimicrobial and hemolytic activity., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)