Effect of green tea and ginger on cariogenic bacteriaRebecca R. G., Geetha R.V.*, Dr. Ravindra Kumar**Graduate Student, Saveetha Dental College and Hospitals, Chennai*Faculty of Microbiology, Saveetha Dental College and Hospitals, Chennai **Reader, Saveetha Dental College, Chennai ABSTRACTDental caries (tooth decay) is one of the common dental problem in most countries, affecting 60-90% of school children and the majority of adults. Reports have brought out the evidence that green tea and ginger have a synergistic impact to limit the growth of bacteria such as E.coli owing to their anti-microbial effects. So the aim of the present study was to evaluate the anti bacterial activity green tea and ginger alone and also their synergistic activity on Streptococcus mutans, the potent initiator and leading cause of dental caries worldwide. Antibacterial activity of green tea along with ginger was screened against Streptococcus mutans, using agar well diffusion technique. The results of this study showed that both green tea and ginger has got good antibacterial activity. But they didn’t exhibit synergistic activity on the organism tested.Key words : Dental caries, agar well diffusion, synergistic effect, green tea, ginger.INTRODUCTIONDental caries is the demineralisation of the tooth surface caused by bacteria. 1,2 The bacterial aspect of dental caries can be explained such that the bacteria produce acids that cause the irreversible solubilisation of tooth structure. Streptococcus mutans is the main cause of dental decay while various lactobacilli are associated with progression of the lesion. Reports have brought out the evidence that green tea and ginger have a synergistic impact to limit the growth of bacteria such as E.coli owing to their anti-microbial effects. 3,4Ginger has been known for medicinal purposes since antiquity. Ginger is from the botanical family Zingiberaceae. Its botanical name is Zinger officinale. The parts of the ginger plants that are of medicinal value are the rhizomes (underground stems). Ginger has long been an alternative therapeutic to prevent motion sickness i.e, nausea and vomiting. Its synergistic and individual impact with green tea is found to affect some bacterial populations. Zingiber officinale (or ginger), is one of the most extensively used herbs in the Indian system of traditional medicine. Many studies have revealed its numerous phar- macological activities, such as, antioxidant, antibacterial, anti-inflammatory, anti-nociceptive 5, anti-mutagenic 6 and hepatoprotective 7. Furthermore, there are several other studies showing the antibacterial effect of Z. officinale against a number of micro-organisms including S. mutans 8-10. However, there are hardly any reports evaluating its anticariogenic potential. Hence, in view of the current need of alternative therapeutic approach, we initiated our study to provide an innovative and comprehensive insight of the effect of Z. officinale to inhibit various virulence traits of S. mutans.Green tea (Camellia assamica) is cultivated in many countries of the countries of the world, Japan being the largest producer in the world. Green tea has been chosen as a raw material for extracts used in different beverages, dietary supplements and cosmetic items. Green tea is derived from the dried leaves of the plant Camellia sinensis. Green tea is usually available in the form of beverage, mouth wash containing extract of green tea, and as a chewing gum. Green tea catching can be altered by different factors like type of green tea leaves , type of processing before drying, growing conditions and the geographic conditions. 11 Significant antibacterial activity has been reported for extracts of green tea. Green tea is observed to inhibit the growth of bacteria such as Streptococcus mutans and Lactobacillus acidophilus.MATERIALS AND METHODSTest microorganismsBacterial strain used was Streptococcus mutans. The organism was isolated. Isolation was done using selective media Mutans-Sanguis agar Hi media M977, and maintained in nutrient agar slope at 4?C in Department of Microbiology, Saveetha Dental College.MethodologyThe green tea and ginger were dissolved in distilled water in following concentrations 2.5mg/ml, 5mg/ml and 10mg/ml so that 100µl delivers 250µg/ml, 500µg/ml and 1000 µg/ml respectively. Screening of antibacterial activity Agar well diffusion techniqueBroth culture of the specified bacterial strain according to Mac Farland’s standard 11-13 0.5 was prepared. On Muller Hinton agar MHA-Hi media M1084 plates lawn culture of the test organisms was made using sterile cotton swab and plates were dried for 15 minutes. Using a sterile well cutter wells measuring 4mm depth were made on the agar plates. 100 µl of different concentration of the extract were then filled in the wells. To determine the synergistic activity 50µl of green tea and 50µl of zinger extract from different concentrations were loaded on to the wells. 0.2% chlorhexidine was used as the positive control. The plates were incubated at 37°C overnight and the zone of inhibition of growth was measured in millimeters. All the tests were done in triplicate to minimize the test error.RESULT AND DISCUSSIONThe antibacterial activity of green tea and ginger at different concentrations was screened by agar well diffusion technique and zone of inhibition was measured in mm diameter. The results are given in Table 1. The green tea alone was more effective against Streptococcus mutans with a zone of inhibition of 22mm; ginger showed a zone of 19mm diameter and with both green tea and ginger the zone diameter was 20 mm.The present study was to analyse the antibacterial activity of green tea and ginger alone and together on caries causing organisms. The results obtained from our study show that green tea and ginger have good antibacterial activity but do not have much of a synergistic impact against Streptococcus mutans.