Pharmaceutical Sciences September 2016, 22, 164-169 doi: 10.15171/PS.2016.26 http://journals.tbzmed.ac.ir/PHARM Research Article A Study on Antimicrobial Activities of Essential Oils of Different Cultivars of Lemongrass (Cymbopogon flexuosus) Ashish Kumar Gupta, Ritam Muhury, Deepak Ganjewala* Amity Institute of Biotechnology, Amity University Uttar Pradesh, Sector-125, Noida-201 303 (UP), India A r t i c l e I n f o A B S T R A C T Article History: Background: Cymbopogon flexuosus popularly known as lemongrass provides Received: 20 Dec 2015 a lemon scented essential oil which is widely used in flavour and fragrance, Accepted: 10 May 2016 ePublished: 30 September 2016 perfumery, food and pharmaceuticals. The aim of the present study was to assess antimicrobial activities of essential oils of three lemongrass cultivars viz., Keywords: Pragati, Praman and Suvarna. -Cymbopogon flexuosus Methods: Essential oils were isolated from one month old plants by hydro- -Lemongrass -Essential oil distillation in mini Clevenger apparatus for 2 h. Antimicrobial activities were -Citral determined by agar well diffusion method -Agar well diffusion Results: Lemongrass oils exhibited strong antimicrobial activity against all the -Antimicrobial microbes except E coli. Mean inhibition zone diameter (mm) against bacteria was ranged 27-38 mm. B. Subtilis was the most sensitive bacterium to all essential oils. Essential oils also showed strong antifungal effects against both A. niger and C. albicans with mean inhibition zone diameter (mm) values 20- 26 and 27-29 mm, respectively. Statistical analyses revealed that antimicrobial activity shown by essential oils were significant (p < 0.05) against all microorganisms except B. subtilis and C. albicans (p >> 0.05). Conclusion: The study revealed strong antimicrobial potential of the essential oil against pathogenic microbial strains which may be of high clinical importance in future. Introduction centuries to treat diseases and ailments.11 It has been Medicinal and aromatic plants are important pillars used to cure various ailments like cough, cold, of healthcare and traditional medicinal systems of spitting of blood, rheumatism, lumbago, digestive 1 the world. A number of aromatics plants provide problems, bladder problems, leprosy, and as mouth essential oils of unique aroma which is mainly used wash for the toothache and swollen gums. in flavours and fragrances, perfumery, cosmetics Lemongrass provides an essential oil known as and pharmaceuticals.2 Essential oils possess many lemongrass oil which is characterized by the useful bioactivities particularly the antimicrobial presence of monoterpenes such as, citral (a racemic activities which have formed the basis for the mixture of geranial and neral), geraniol, citronellol, development of new alternative citronellal, linalool, elemol, 1,8-cineole, limonene, remedies/therapeutics for the control and inhibition geraniol, methyl heptenone, geranyl acetate and of human and food-borne pathogens and food geranyl formate.12-14 Citral is identified as the major spoilage microorganism’s growth.3-9 Applications of constituent that imparts lemon like aroma to essential oils are often considered quite safe and lemongrass oil. Lemongrass oil and citral are widely effective with no side effects. With increasing used in flavors and fragrance, cosmetics, food and number of bacterial strains resistant to various pharmaceuticals. Citral is also used in soaps, antibiotics, many attempts to use antimicrobial detergents, and for the synthesis of vitamin and potential of plants have been done. Antimicrobial ionones.12-16 Lemongrass oil and citral possessed a compounds from plants with different mechanisms number of bioactivities such as antibacterial, of action against resistant microbial strains are of antifungal, anti-inflammatory, anticancer and clinical importance.10 allelopathic activities.13,15-16 Recently, we reported Cymbopogon flexuosus popularly known as antibacterial properties of lemongrass essential oils lemongrass is indigenous to India. It is generally separately and in combination with honey and of used as an important ingredient in Ayurveda an silver nanoparticles synthesized from lemongrass oldest system of medicine practiced in India for leaf extract against drug resistant pathogenic *Corresponding Author: Deepak Ganjewala, E-mail: [email protected] ©2016 The Authors. This is an open access article and applies the Creative Commons Attribution (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers. Kumar Gupta et al. bacteria.17-18 According to previous studies a Antimicrobial assay number of pathogenic bacteria have been Antimicrobial activities of essential oils obtained continuously evolving resistance mechanism against from three cultivars of lemongrass namely, Suvarna, currently available antibiotics and posing serious Praman and Pragati were determined by agar well threats to human health. This trend has necessitated diffusion method and compared.20 The culture plates the discovery of new antimicrobial compounds were prepared by first sterilizing the MHA and PDA against drug resistant bacterial and fungal in an autoclave at 121ºC at 15 lb for 15 minutes and pathogens. Lemongrass oils owing to their then by pouring 20 ml of media into each sterilized tremendous bioactive potential could be a good Petri dish used. One milliliter (1 ml) inoculums source of new antimicrobial agents of clinical suspension was spread uniformly over the agar importance and may useful in treatment of various medium using sterile glass rod. Wells were made by forms of infections caused by pathogenic using sterile cork borer (6 mm) in each plate. microorganisms. The aim of the present study was Essential oil samples (10 μl) were inserted to determine antimicrobial properties of essential aseptically with the help of micropipette into the oils of three lemongrass cultivars namely Pragati, well. The bacterial media plates were incubated at Praman and Suvarna against bacterial and fungal 37ºC for 24 h and fungal plates for 48 h at 30ºC. pathogens associated with human diseases. After incubation, microbial growth and the zone of inhibition (mm) were measured and compared to the Material and Methods controls. Antimicrobial assays were performed in Plant Material triplicate. Lemongrass (Cymbopogon flexuosus Steud.) Wats plants were raised at Organic Farm House of Amity Statistical analysis University Uttar Pradesh, Noida (U.P.) following The mean and standard deviation of mean of standard agronomic practices. It took almost a year inhibition zone (MIZ) diameter (mm) were to acclimatize and grow well. At the time of study calculated. Statistical significance was measured by plants were harvested from 10 cm above the ground using one-way ANOVA followed by Tukey’s post- level and tagged. Plants were allowed to grow for hoc test. Analysis of data was done by IBM SPSS one month and then were harvested for isolation of (statisrical package for social science) version 19.0. essential oils. Results and Discussion Isolation of essential oil Antimicrobial activity profiles of essential oils of One month old lemongrass plants were harvested; three cultivars of lemongrass namely Pragati, leaves were separated, washed thoroughly and cut Praman and Suvarna are presented in Table 1. into small pieces. Leaves (100 g) were subjected to Antimicrobial activities were determined by agar steam-distillation in mini Clevenger apparatus for 2 wel diffusion method and expressed in terms of MIZ h.19 The volume of the essential oil accumulated in diamter (mm). All the three essential oils tatsted the burette of Clevenger apparatus was measured showed good antimicrobial activities against and collected in small vials. Anhydrous sodium bacteria and fungi used. Overall average values of sulphate was added to vials in order to remove last MIZ against bacteria was ranged 27-38 mm and traces of moistures in essential oils. Essential oils fungi 23-30 mm, respectively. All of essential oils were stored at 4°C in refrigerator till further use. were highly effective against B. subtilis and less effective against E. coli. However, Suvarna essential Culture of microorganism oil showed strong antibacterial activity against B. Four bacterial pathogens including Escherichia coli subtilis follwed by essential oils of Praman and (MTCC901), Pseudomonas aeruginosa, Pragati (Table 1). The essential oil of suvarna also Staphylococcus aureus (MTCC96) and Bacillus exhibited highest bactericidal effect against S. subtilis (1429) and two fungal pathogens aureus and P. aeruginosa. Essential oils of Praman Aspergillus niger (MTCC2723) and Candida and Pragati displayed almost similar bactricidal albicans were obtained from Microbiology effects as that of suvarna agianst same set of bacteria Laboratory, Amity Institute of Biotechnology, but with little less values of MIZ 28-30 mm. The Noida, Uttar Pradesh. The bacterial and fungal Essential oils of lemongrass cultivars tasted here cultures were inoculated in Muller Hinton Agar also showed strong antifungal effects against C. (MHA) and Potato Dextrose Agar (PDA), albicans with values of zone of inhibition 29-30 respectively. The pure colonies were sub-cultured mm. However, Suvarna essential oil showed strong and preserved in agar slants at 4º C and 50 % antifungal activity against A. niger causing a zone of glycerol stock at -20ºC.