Exploring of Antifungal and Antibacterial Effects of Green Mint (Mentha spicataL.) on Microbial infection

Abstract

Plants possess extraordinary therapeutic virtues. They contain a large number of molecules with multiple applications in the pharmaceutical industry, food, cosmetics, and dermopharmacy. Much of current research focuses on the study of antimicrobial molecules, making it interesting to position our work within this research context. The objective of our study is to evaluate the antibacterial and antifungal activity of extracts from the leaves of Mentha spicata from the Saida and El-Bayedh regions against  microbial strains.Our extract preparation was carried out through maceration using 80% methanol. The total polyphenol content was determined by spectrophotometry using the Folin-Ciocalteau method, the total flavonoid content was estimated using a colorimetric method with aluminum chloride solution, and the condensed tannins were measured using a vanillin-HCl test.The antibacterial activity was assessed using the aromaticogram method with the well diffusion technique. The extracts of Mentha spicata were tested on two culture media, Muller Hinton and Sabouraud, against four pathogenic strains: Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC 25923), Candida albicans (ATCC 10231), and Bacillus cereus (ATCC 11778).Experimental results revealed that the extract from the Saida region is richer in total polyphenols than the extract from El-Bayedh, with values of 180.16 and 138.5 mg EAG/g of extract, respectively. It also contained more flavonoids (6.15 and 5.1 mg EQ/g of extract) and higher levels of condensed tannins (72 and 57.83 mg EC/g of extract from Saida, being more effective than the extract from El-Bayedh).Regarding antibacterial activity, our results show that S. aureus is sensitive to the concentrations of 20% (IZ = 10 mm, 8 mm for Saida and El-Bayedh, respectively), 40% (IZ = 14 mm, 13 mm), and very sensitive to 60% (IZ = 16 mm, 15 mm), 80% (IZ = 17 mm, 15 mm), and 100% (IZ = 19 mm, 16 mm). Bacillus cereus is resistant at 20%, 40%, 60%, and 80%, but sensitive at 100%, with a diameter of 9 mm for both extracts. E. coli is sensitive at 20% (IZ = 9 mm, 8 mm), 40% (IZ = 10 mm, 10 mm), 60% (IZ = 10 mm, 11 mm), 80% (IZ = 11 mm, 11 mm), and 100% (ZI = 12 mm, 11 mm). Candida albicans is resistant at 20% and sensitive at 40% (IZ = 9 mm, 8 mm), 60% and 80% (ZI = 10 mm, 8 mm), and at 100% (IZ = 14 mm, 12 mm).These findings encourage further studies on extracts from a variety of medicinal plants to maximize their benefits.