Aims: Plant extracts are a rich source of natural compounds that have some degree of antimicrobial efficacy and have less side effects compared to antibiotics. The aim of this research was to screen the phytochemical compounds and investigate the potency of Curcuma zedoaria (Christm.) Roscoe rhizome (CZR) extracts to inhibit the growth and biofilm formation of some pathogenic bacteria. Methodology and results: Antimicrobial and antibiofilm effects of CZR extracts in different solvents were examined by agar well diffusion and the broth microdilution method after phytochemical screening. The 95% ethanolic extract of CZR exhibited broad-spectrum antibacterial properties against Gram-negative and Gram-positive bacteria with inhibition zones of 7.25 ± 0.58-12.00 ± 0.26 mm and MIC values ranging from 50-200 mg/mL. The extract also showed rapid bacteriostatic and bactericidal activities towards Enterococcus faecalis DMST 4736 and Staphylococcus aureus ATCC 25923 by time-kill assays. Moreover, the 95% ethanolic extracts of CZR also acted as a potent anti-biofilm agent against E. faecalis DMST 4736, S. aureus ATCC 25923, S. epidermidis, Escherichia coli ATCC 25922, Klebsiella pneumoniae, Pseudomonas aeruginosa ATCC 27853 and Proteus mirabilis DMST 8212 (54.62 ± 0.30-71.25 ± 0.20% inhibition of biofilm formation). The bioactive potency of compounds of the crude 95% ethanolic extract (tannins, flavonoids, cardiac glycosides, steroids, terpenoids and alkaloids) play important roles in the observed antibacterial and anti-biofilm activities. Conclusion, significance and impact of study Curcuma zedoaria (Christm.) Roscoe extract had broad-spectrum antibacterial activity. The ethanolic CZR extract revealed bacteriostatic and bactericidal capacities, depending on time of exposure and concentration of the extracts. Thus, the present results indicate that C. zedoaria (Christm.) Roscoe rhizomes are a potential natural alternative antibacterial agent for preventing bacterial diseases.
Phytochemicals--analysis ; Curcuma

Aims: The occurrence of bacterial disease in shrimp ponds is a major problem faced in shrimp farming. Thus, the aims of this study were to isolate and evaluate antibiotic resistant profile of Vibrio harveyi strain isolated from shrimp pond water, as well as to study the potential anti-Vibrio activity of Combretum quadrangulare Kurz. (CQ) and Mimosa pudica (MP) leaves extracts. Methodology and results: Vibrio harveyi WSC103 was isolated from water in white shrimp (Litopenaeus vannamei) culture pond and identified using 16S rRNA gene sequencing analysis. This strain showed characteristics of multidrug-resistant (7 antibiotics). It had become more sensitive to antibiotics (9 out of 10 antibiotics) after plasmid curing. It is showed CQ and MP leaves extracts contain potent bioactive compounds (tannins, flavonoids, steroids, cardiac glycosides and alkaloids) against V. harveyi WSC103. The aqueous, 95% ethanolic and 75% acetone extracts of CQ (MIC value of 3.13-12.50 mg/mL) and MP (MIC value of 3.13-25.00 mg/mL) leaves revealed strong vibriostatic activity, but aqueous and 95% ethanolic extracts in both plants showed vibriocidal activity. The 95% ethanolic extract of both CQ and MP leaves displayed the excellent vibriocidal property with MBC value of 100 mg/mL with zone of inhibition at 11.44 ± 1.01 and 11.78 ± 1.01 mm by agar disc diffusion. Conclusion, significance and impact of study The isolated Vibrio harveyi WSC103 was successfully characterized as a novel multidrug-resistant strain. The ethanolic C. quadrangulare Kurz. and M. pudica extracts exhibited prominent vibriostatic and vibriocidal capacities. These finding is proven that C. quadrangulare Kurz. and M. pudica extracts would be an alternative anti-Vibrio agent for aquaculture infectious treatment.
Vibrionaceae ; Gram-Negative Bacteria ; Combretum ; Mimosa