TLC-bioautography-guided valorization of vetiver (Chrysopogon spp.) leaf extracts into an anti-acne gel.

The growing issue of antimicrobial resistance (AMR) in acne-related bacteria continues to undermine the effectiveness of standard treatments. This study examined the antibacterial potential of Chrysopogon spp. leaf biomass. The leaves, which are often discarded or used locally as mulch to help retain soil moisture, are an underused agricultural byproduct. Leaf extracts were obtained from five cultivars using different ethanol and water-based solvent systems and were screened against Cutibacterium acnes, Staphylococcus aureus, and Streptococcus pyogenes. The 50% ethanolic extracts showed the strongest and most consistent inhibition patterns, with MIC values ranging from 7.81 to 125 mg/mL. TLC-bioautography was employed to identify active components, which were primarily located within the mid-polar Rf range. Topical gels were developed using 4% and 5% w/w of the most active extract showing the strongest antibacterial effect, which was found in the Huai Kha Khang cultivar. The 5% gel exhibited inhibition zones of 6–20 mm, stayed stable and maintained its antimicrobial activity after four weeks of storage at 4 ± 1 °C, 25 ± 2 °C, and 45 ± 2 °C. These findings highlight the therapeutic potential of underutilized vetiver leaves as a plant-based resource for anti-acne gel formulations in AMR-sensitive applications.