Anti-Acne Inducing Bacteria and Free Radical Scavenging Activities of Turmeric Rhizome Extracts Prepared Using Different Solvents

Turmeric (Curcuma longa Linn.) of the family Zingiberaceae is one of the most popular medicinal plant used in food, drugs and cosmetics for a long time. It contains high amount of curcuminoid, especially curcumin which is a major constituent and responsible for numerous biological activities [1]. The purpose of this study is to compare anti-acne inducing bacteria and antioxidant activities of turmeric rhizome extracts which were prepared using different solvents i.e, hexane, dichloromethane, ethanol and water. All extracts were tested for antibacterial activities against bacteria causing acne, including Propionibacterium acnes, Staphylococcus epidermidis and Staphylococcus aureus, using broth microdilution method [2]. They were also evaluated for antioxidant activity using DPPH scavenging assay [3]. Additionally, the content of curcumin content of each extract was analyzed by HPLC [4]. The dichloromethane and ethanol extract exhibited the strongest antibacterial effect with MIC values for all bacterial species at 78 µg/ml and MBC values at 156.25 µg/ml. Based on DPPH scavenging method, it indicated that the dichloromethane extract of turmeric rhizome promoted the strongest DPPH scavenging effect (IC₅₀= 7.16 µg/ml), while the water extract showed poor antioxidant activity (IC₅₀= 375.29 µg/ml). By HPLC, the dichloromethane extract yielded the highest content of curcumin (18.87%w/w) followed by the ethanol extract (9.18%w/w), the hexane extract (0.54%w/w), and the water extract (0.01%w/w), respectively. These findings suggest that the dichloromethane extract of turmeric rhizome should be a potential source of natural anti-acne inducing bacteria and antioxidant agents for further development of pharmaceutical preparations.

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[2] Chomnawang MT, et al. J Ethnopharmacol 2005; 101: 330 – 333.

[3] Sithisarn P, et al. Evid Based Complement Alternat Med 2015: doi:10.1155/2015/908242

[4] Wichitnithad W, et al. Phytochem Anal, 2009; 20: 314 – 319.