Antibacterial activity of Allium sativum extract on common upper respiratory tract infections

Abstract

Upper respiratory tract infections such as pharyngitis sinusitis, tonsillitis and pneumonia which contribute to the disease burden in Uganda are managed by use of antibiotics. This has caused increased antibiotic resistance among bacterial pathogens responsible for these infections. Garlic is one of the most widely used herbs with acclaimed medicinal potential and has been used to treat respiratory infections. Therefore, this study aimed at determining the antibacterial activity of both the indigenous and exotic garlic species of Allium Sativum family on representative pathogens Streptococcus pneumoniae and Klebsiella pneumoniae. Ethanolic extracts of Allium Sativum extracts were evaluated for phytochemicals and antibacterial activity against S. pneumoniae and K. pneumoniae. The exotic garlic extract was found to contain more saponins, Flavonoids and Alkaloids compared to the indigenous garlic ethanolic extract. Both exotic and indigenous garlic ethanolic extracts contained considerably equal amounts of phenolic compounds. However, the indigenous garlic ethanolic extract was also found to contain Tannins which was absent in exotic garlic ethanolic extract. The indigenous garlic extract showed a mean zone of clearance of 8mm and 8.5mm whereas the exotic garlic extract showed a mean zone of clearance of 8.5 and 9mm against S. pnemoniae and K. pneumoniae respectively. This was achieved using the Agar well diffusion method. However, using the broth dilution method on a 96 microtitre plate, both ethanolic garlic extracts showed the same value for both minimum inhibitory concentration and minimum bactericidal concentration of 0.5 g/ml against both S. pneumonia and K. pneumoniae. This study showed that ethanolic extract of Allium sativum contain important and active phytochemical compounds which justify the need to consider it as having antibacterial properties that can be of relevance to pharmaceutical science.