Sustainable valorization of Eclipta alba (L.) Hassk. Stem using eco-friendly extraction: Bioactive compound profiling and in vitro wound-healing assessment

Eclipta alba (L.) Hassk., known as a medicinal or herbal crop across Asia, including Myanmar and Thailand, is used for skin ailments. Despite extensive research on the bioactive compounds in its leaves and whole plant, the therapeutic potential of the plant's stems remains largely unexplored. This study aimed to explore the wound-healing potential of E. alba (L.) Hassk. stems by optimizing ultrasound-assisted extraction with an aqueous propylene glycol (PG) system using Box-Behnken Design. The aqueous propylene glycol E. alba stem extract (EUPG) was assessed by antioxidant, antibacterial, anti-inflammatory, and wound-healing activities. Optimal extraction conditions were determined as 10 min of extraction time, liquid-solid ratio of 28.57 mL/g, and a solvent concentration of 47.80 %. The EUPG yielded higher bioactive compounds and exhibited greater antioxidant activity compared to other methods. LC-QTOF-MS/MS analysis identified 21 bioactive compounds including six newly reported bioactive compounds. The EUPG exhibited its antimicrobial activity against Staphylococcus aureus, Streptococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. Additionally, the EUPG inhibited human 5-lipoxygenase by 31.48 ± 4.99 % at 62.5 mg/mL and displayed nitric oxide (NO) scavenging activity (6.13 ± 0.26 mg GAE/g). The EUPG exhibited NO inhibition in lipopolysaccharide-induced RAW 246.7 macrophage cells with an IC50 value of 26.98 mg/mL, with a notable 78.07 ± 2.68 % inhibition at 50 mg/mL. In a cell scratch assay using HaCaT keratinocytes, the EUPG showed the wound closure of 65.90 ± 3.06 % at 10 mg/mL. This study presents the EUPG as a sustainable, ready-to-use active ingredient for cosmetic and pharmaceutical applications, aligning with eco-friendly innovations in health and skincare.