Abstract:
In recent years, infectious diseases have risen dramatically in prevalence, becoming a major
worldwide health concern. The advent of antibiotic-resistant bacterial strains, as well as the
associated side effects and toxicities, has challenged the efficiency of many antibiotics, resulting
in inefficient therapy. Thus, discovering alternative antimicrobial agents with higher efficacy and
lesser toxicity is of utmost importance. In this context, the utilization of natural herbs used in
traditional medicine for identifying potential antimicrobial agents has attracted the interest of
many researchers and practitioners. Despite the wide variety of therapeutic capabilities, Clitoria
ternatea L. is an underutilized medicinal plant. In this study, the antibacterial potential of C.
ternatea L. blue paired flowers (corolla with standard five petals) and blue solitary (corolla with
one large standard petal, two wrinkled wings, and two white keels) flowers were evaluated
against the selected control strains of human pathogenic bacteria, Staphylococcus aureus,
Escherichia coli, and Pseudomonas aeruginosa. The Soxhlet extraction technique was used to
prepare the solvent extracts (ethanol, ethyl acetate, dichloromethane, chloroform, petroleum
ether, and hexane) of each flower form. The minimum inhibitory concentration (MIC) and
minimum bactericidal concentration (MBC) were determined using a broth microdilution assay
in Mueller-Hinton broth in 96-well microtiter plates. The highest extraction yield percentages
(W/V) were obtained from the ethanol extracts of blue paired (21.02%) and blue solitary
(10.06%) flowers. The results of broth microdilution assay revealed that all the C. ternatea blue
paired and blue solitary solvent extracts were effective against strains of S. aureus and E. coli,
whereas P. aeruginosa was resistant to all the tested petroleum ether and hexane extracts. The
dichloromethane and chloroform (MIC and MBC values ranged from 0.13 mg/mL to 2 mg/mL)
extracted blue paired and blue solitary flower forms have shown significant antibacterial activity
(p<0.05). Further, the study showed that different solvent extracts from the same plant flowers
had varying degrees of inhibition when tested against different bacteria. Thus, the current
investigation verifies the therapeutic use of C. ternatea blue flowers in traditional medicine and
demonstrates their potential to be exploited in the discovery of novel antimicrobial agents, which
is an important step forward.
