Ethanol extract of turmeric [Curcuma longa Linn. (Zingiberaceae)] was investigated for its in vitro antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and activities against six microorganisms (Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphyloccoccus aureus, Candida albicans and Cryptococcus neoformans). Clear liquid soaps containing 0.5% w/v turmeric extract were formulated. The only one preparation with acceptable appearance, foam and viscosity was selected for antimicrobial activity and stability studies. It was found that turmeric extract had 50% radical scavenging ability (EC50) at concentration of 11.26 µg/ml against DPPH. Turmeric extract was showed no activity against Escherichiacoli and Pseudomonas aeruginosa. The minimum inhibitory concentration of turmeric extract against Bacillus subtilis, Staphyloccocus aureus, Cryptococcus neoformans and Candida albicans were 16, 128, 128 and 256 µg/ml, respectively. The selected preparation was physically and chemically stable and the antimicrobial activity did not change (p<0.05) under the heating-cooling stability test. However, curcumin content and the antimicrobial activities against S. aureus and C. neoformans decreased significantly (p<0.05) under the accelerated test conditions (temperature 45oC, 75% RH for 4 months) and after storage at room temperature for 12 months. The results of a clinical trial with HIV patients found that this liquid soap decreased itching symptom (100%) and infectious wound and abscess became dryness scabs (78.6%) within 2 weeks.
