International Journal of Applied Pharmaceutics ISSN - 0975 - 7058 Vol 11, Special Issue 5, 2019 IN VITRO ANTIMICROBIAL ACTIVITY OF SOME ESSENTIAL OILS AGAINST BACTERIAL PATHOGENS CAUSING SKIN DISEASES IN VAPOR PHASE PURIT PATTANAPANIT, SUNISA MITHONGLANG, SUNITA MITHONGLANG, SURACHAI TECHAOEI* Thai Traditional Medicine College, Rajamangala University of Technology Thanyaburi, Pathum Thani, Thailand. Email: surachai_te@rmutt.ac.th Received: 26 December 2018, Revised 29 December 2018 and Accepted: 16 February 2019 ABSTRACT Objective: The objective of this study was to evaluate the antimicrobial activity of volatile oils from aromatic plants against pathogenic bacteria. Methods: Thai aromatic plants such as Pogostemon cablin (Blanco) Benth (Patchouli oil), Cymbopogon nardus Rendle (Citronella grass oil), Pelargonium roseum (Geranium oil), Syzygium aromaticum (L.) Merrill and Perry (clove oil), Cinnamomum spp.(cinnamon oil), and Cymbopogon citratus (DC.) Stapf. (lemongrass oil) were selected. Essential oils were obtained by water distillation and were stored at 4°C until use. Five human pathogenic bacteria were obtained from Thai traditional Medicine College, Rajamangala University of Technology, Staphylococcus epidermidis, Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Pseudomonas aeruginosa. The antibacterial activity of volatile oils was determined by disc-diffusion assay. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each essential oil were determined. Results: Our study showed that 10% of essential oil from Cinnamomum spp. was the most potential against S. aureus, MRSA, and E. coli when assayed by disc-diffusion method with inhibition zones ranging from 37.66±0.57 to 45.33±1.15 mm and from 29.33±0.57 to 36.00±1.00 for lemongrass oil with MIC and MBC of 1.25%. Conclusion: From this study, it can be concluded that some essential oils have potential antibacterial activity. The present investigation provides support to the antibacterial properties of essential oils and will be applied to health-care product as aroma antibacterial products. Keywords: Antibacterial activity, Skin diseases, Volatile oils, Pathogen. INTRODUCTION Skin infectious disease is a disorder of exclusively the superficial layers of the skin, infected by organisms such as bacteria, viruses, fungi, and parasites [1]. The pathogens including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and drug- resistant bacteria caused several skin human infections [2-8]. Thus, the global prevalence of infectious disease caused by bacteria is a major public health problem [9]. However, it is important to note that the effects of synthetic drugs can be highly unpredictable, making difficult to fully assess their physical impact. Hence, the natural compounds or essential oils from medicinal plant have an alternative to treat the antimicrobial agent. Medicinal plants have been used as primary treatment of skin disorders for centuries in Thailand Traditional Medicine, Chinese Traditional Medicine, and Indian Traditional Medicine. Essential oils of medicinal plants present a great potential of application as natural antimicrobial agents [9]. They are mixtures of natural volatile molecule deriving from plant secondary metabolism which potent antibacterial, antifungal, antiviral, insecticidal and antioxidant activities. Generally, the biological activity of essential oil depends on their chemical structure, environmental, and agronomic conditions [10]. Thus, the objective of this research was to screen the antibacterial activity of volatile oil from medicinal plants in Thailand against skin human pathogenic bacteria. METHODS The extraction of essential oils from medicinal plants Pogostemon cablin (Blanco) Benth (Patchouli oil), Cymbopogon nardus Rendle (Citronella grass oil), Pelargonium roseum (Geranium oil), Syzygium aromaticum (L.) Merrill and Perry (clove oil), Cinnamomum spp.(cinnamon oil), and Cymbopogon citratus (DC.) Stapf. (lemongrass oil) were selected. Briefly, the medicinal plant was completely immersed in water and heated to boiling, after which the essential oil was evaporated together with water vapor and finally collected after decantation. The distillate was isolated and dried in a Rotavapor to giving greenish-yellow oil. The oil was stored at 4°C until the antimicrobial screening [11]. Antibacterial activity of the essential oils Microorganisms Antimicrobial activity determination was carried out against bacterial pathogens causing skin diseases, Staphylococcus epidermis, E. coli, methicillin-resistant S. aureus (MRSA), S. aureus, and P. aeruginosa. Culture media Bacteria were assayed on nutrient agar (NA) (Merck, g/L):peptone from meat, 50.0; meat extract, 3.0; agar, 12.0; and water, 1.0 L. Inocula Inocula for the assays were prepared by incubation at 37°C for 18 h before use and were adjusted to McFarland scale of 0.5. Cell suspensions were finally diluted to 10 4 cfu/ml for being used in the activity assay. Disc volatilization assay This assay requires a culture agar plate inoculated with microbial suspension adjusted by McFarland No.0.5 containing 10 6 cfu/ml inserted down on top of a container (Fig. 1). A paper disc (6 mm) is deposited at the bottom of the container with 15 µl of essential oils. All plates inoculated and the disc should be sealed with parafilm to prevent the steam outlet and incubated at 37 C for 24 h, and the inhibition zone was measured in millilitre (mm) [12]. The experiments were done by tree replicates (Fig. 1). © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ijap.2019.v11s5.T0084 4 th International Conference on Pharmacy and Pharmaceutical Science (ICPPS) 2019 Research Article