Phytochemical Constituency and Antimicrobial Activity Analysis of Tea and Agar-Wood Leaf Extracts Against Multi-Drug Resistant Microbes

Abstract

Plants derived bioactive compounds have taken the attention in the pharmacological sectors due to their potential therapeutic application with lower side effects. Besides in the threat of antibiotic resistance and the scarcity of effective antibiotics, bioactive compounds from plants can be a promising solution for this critical circumstance that can be implemented on alleviation and cure of pathogenic disease. In this study, comparative antimicrobial activity Tea (Camellia sinensis) including fresh tea (BT-6, BT-7 and BT-8 total three variety) leaves, non-fermented Green tea (GT), fermented Black tea (BT) and Agarwood (Aquilaria malaccensis) leaves extracts were analyzed against different pathogenic bacteria and fungus. Qualitative and quantitative phytochemical constituency profiling of these six leaf extracts were evaluated and preliminary screening exhibited that most of the leaf contained diverse groups of metabolites (Alkaloids, Tannin, Flavonoids, Saponins etc.).The highest 110.16±0.48 µg/mg amounts of TPC (Total Phenolic Content) were found BT-7 in ethanol extracts and BT-8 in methanol extracts possessed the highest 128.1±0.43µg/mg TFC (Total Flavonoid Content) besides both in TPC and TFC Green tea showed remarkable results. In antioxidant scavenging activity, BT-7 and Green tea showed significant IC50 values were 13.23 mg/ml and 20.75 mg/ml respectively. However, leaf extracts phytochemicals and antimicrobial activities against the microbes varied the results in accordance to the leaf type, microbial variant and solvent types. In the antimicrobial activity test, Green tea showed a maximum diameter (22.0±1.1 mm) zone of inhibition against the Klebsiella spp. whereas BT-8 showed (22.0±2.5 mm) against Pseudomonas spp. Indeed, both BT-6, and BT-7 showed remarkable zone of inhibition against the selected microbes including gram-negative and gram-positive bacteria. Besides, leaf extracts also showed antimicrobial activity against pathogenic fungus Mucor circilidones. To minimize antibiotics resistance, synergistic activity contrary to the selected pathogens had experimented where synergism, antagonism and additive results were noted. Combination with BT-8 extracts with antibiotics (Ceftiofur) showed the highest synergism nearly 36mm of the zone of inhibition against E.coli. Additionally, Green tea with Gentamicin and Erythromycin also showed remarkable synergism (35mm and 33mm) against Mucor circilidones and E.coli respectively. More synergism was listed against the fungus Mucor circilidones and no synergism but additive results were identified against Staphylococcus spp.

Keywords: Multi-drug resistant microbes, Antimicrobial activity, Phytochemicals, Natural Antibiotics, Synergistic activity