Antimicrobial Effect of Emodin Isolated from Cassia tora Linn. Seeds against Food-Borne Bacteria

Abstract

Abstract The antimicrobial activities of emodin and its derivatives(anthraquinone, alizarin, and alizarin-3-methyliminodiacetic acid)were evaluated using a paper disc diffusion method against food-borne bacteria (Bacillus cereus, Listeria monocytogenes,Staphylococcus intermedius, Salmonella typhimurium andShigella sonnei). Emodin isolated from C. tora seeds has anantimicrobial activity against Bacillus cereus, followed byalizarin-3-methyliminodiacetic acid (13.0±2.5 mm) and alizarin(11.5±1.2 mm). Furthermore, emodin showed the antimicrobialactivity against S. sonnei and S. typhimurium. In conclusion, C.tora seed and its active component derivatives are useful for thedevelopment of natural products on food supplemental agents andpharmaceuticals. Keywords antimicrobial activity · Cassia tora seeds · emodin ·food-borne bacteriaFor the last decades, food industry has emphasized effort todevelop their products modified from the current market. Sometechniques have been devised to prevent the microorganismproliferation from the food degradation and the risk of pathogens(Appendini and Hotchkiss, 2002). The concerns about food safetyhave being continued because of the outbreaks of new food-bornedisease caused by pathogenic microorganism. Although chemicalor artificial preservatives are already used to inhibit or inactivategrowth of various kinds of pathogenic microorganisms, some ofthem have been caused to unwanted effects such as allergicdiseases (Fleming-Jones and Smith, 2003; Powella et al., 2011;Liang et al., 2012). The natural substances as alternatives may beemployed (Kim et al., 2013). Therefore, these play the importantroles in future food preservation markets.Cassia tora Linn. is an annual small shrub which grows inAsian countries. It is commonly known as ‘Sicklepod’ (Maity etal., 1998). The seed extracts of C. tora have been used in Chinesemedicine as an aperient, anti-asthenic and diuretic agent and alsoto improve visual activity (Asolkar et al., 1992; Maity et al.,1998). The seeds of C. tora contain several anthraquinoneglycosides and naphthopyran glycosides. The seed extract is alsoreported for its hypotensive activity. Many medicinal propertiessuch as antihepatotoxic, antimicrobial, and antimutagenic activitieshave been attributed this plant (Wong et al., 1989; Choi et al.,1997; Yen and Chung, 1999; Patil et al., 2004). To substantiate theclaim, this study was initiated to evaluate the antimicrobial effectsof C. tora seeds and active components against food-bornebacteria.Alizarin, alizarin-3-methyliminodiacetic acid, and emodin werepurchased from Fluka Chemical (Germany) and anthraquinoneand tetracycline were provided from Sigma Chemical (USA). Theother chemicals were of reagent grade. The seeds of C. tora werepurchased from a local market in Jeonju and the extraction andpartition of C. tora seeds were performed as modified from Kimet al. (2004). C. tora seeds (5 kg) were extracted twice withmethanol (10 L) in the shaking incubator at 30