Timnoy Salitxay, Xaykham Onphachanh, Anousone PHANTHAVONG, Khantavanh Phomlasaboud, Mith SAYVANDY, Seng Aloun Sounthaly
Background and objective: Hand sanitizer is considered as a practical alternative to traditional handwashing when soap and water are not available. This study aimed to determine the optimal concentration of various medicinal plant extracts for microbial inhibition and to evaluate the effectiveness of hand sanitizer gels formulated with these extracts. Methodology: A Total of five medicinal plants, including: Citrus hystrix DC, Azadirachta indica, Curcuma longa L., Senna siamea (Lam.) H.S. Irwin & Barneby, and Terminalia catappa L. were extracted using 80% ethanol. The selected medicinal plant was applied for hand sanitizer gels formulation and antimicrobial activity was conducted using agar well diffusion assay against microbial isolated from hand swabs. In addition, sensory evaluation of the hand sanitizer gels was tested. Main Result: The results indicated that Terminalia catappa L. leaf extract was the most effective, significantly exhibited a zone of inhibition (1.4423 cm), followed by Senna siamea (Lam.) H.S. Irwin & Barneby with 1.1883 cm and Azadirachta indica (0.9350 cm). In contrast, Citrus hystrix DC showed the lowest efficacy (0.1230 cm). The Minimum Inhibitory Concentration (MIC) for A. indica, S. siamea, and T.catappa inhibited at 12.5 mg/ml, while C. longa and C. hystrix inhibited at higher concentration (25 mg/ml). The optimized hand sanitizer gel formulated with 16 mL of T. catappa extract (F3) demonstrated a high microbial reduction rate of 93.19%, which was comparable to commercial positive controls. In sensory evaluations involving 20 panels tester using a 9-point Hedonic scale, the overall acceptance score was 5.41, indicating a neutral to moderate preference. Among the sensory attributes, gel spreadability gained the highest preference (5.78), whereas color received the lowest (4.89) due to the natural amber hue of the herbal extracts. Conclusion: Terminalia catappa L. leaf extract showed the most potent antimicrobial activity among the five Lao medicinal plant extracts, achieving a significant inhibition zone of 1.4423 cm. The optimized hand sanitizer formulation, mix with 16 mL of this extract (F3), demonstrated a remarkable microbial reduction rate of 93.19%. This Inhibiting performance is comparable to commercial alcohol-based controls, proving the effectiveness of herbal based hand sanitizer gel against hand-borne pathogens.