Screening of the Dichloromethane: Methanolic Extract of Centella asiatica for Antibacterial Activities against Salmonella typhi, Escherichia coli, Shigella sonnei, Bacillus subtilis, and Staphylococcus aureus

Abstract

<jats:p>Bacterial infections are responsible for a large number of deaths every year worldwide. On average, 80% of the African population cannot afford conventional drugs. Moreover, many synthetic antibiotics are associated with side effects and progressive increase in antimicrobial resistance. Currently, there is growing interest in discovering new antibacterial agents from ethnomedicinal plants. About 60% of the population living in developing countries depends on herbal drugs for healthcare needs. This study involved the screening of <jats:italic>Centella asiatica</jats:italic> commonly used by herbal medicine practitioners in Kisii County to treat symptoms related to bacterial infections. Standard bioassay methods were applied throughout the study. They included preliminary screening of dichloromethane: methanolic extract of <jats:italic>Centella asiatica</jats:italic> against human pathogenic bacteria including <jats:italic>Salmonella typhi</jats:italic> ATCC 19430, <jats:italic>Escherichia coli</jats:italic> ATCC 25922, <jats:italic>Shigella sonnei</jats:italic> ATCC 25931, <jats:italic>Bacillus subtilis</jats:italic> ATCC 21332, and <jats:italic>Staphylococcus aureus</jats:italic> ATCC 25923 using agar disc diffusion, broth microdilution method, and time-kill kinetics with tetracycline as a positive control. Phytochemical screening was carried out to determine the different classes of compounds in the crude extracts. Data were analyzed using one way ANOVA and means separated by Tukey’s test. Dichloromethane: methanolic extract of <jats:italic>Centella asiatica</jats:italic> was screened against the selected bacterial strains. Time-kill kinetic studies of the extracts showed dose- and time-dependent kinetics of antibacterial properties. Phytochemical screening of the DCM-MeOH extract revealed the presence of alkaloids, flavonoids, phenolics, terpenoids, cardiac glycosides, saponins, steroids, and tannins. The present study indicates that the tested plant can be an important source of antibacterial agents and recommends that the active phytoconstituents be isolated, identified, and screened individually for activities and also subjected further for <jats:italic>in vivo</jats:italic> and toxicological studies.</jats:p>

GC-MS Analysis, Antibacterial and Antioxidant Potential of Ethyl Acetate Leaf Extract of Senna singueana (Delile) Grown in Kenya

“…To obtain fresh bacterial colonies, the bacterial stock pathogens were streaked on Mueller Hinton Agar (MHA) prior to 24 hours at 37°C [ 48 ]. Thereafter, 3 to 4 colonies were picked with a sterile wire loop and transferred in sterile glass tubes containing 10 ml of sterile Mueller Hinton Broth (MHB) followed by 24 hours of incubation at 37°C to obtain freshly grown bacterial suspensions which were kept at 4°C [ 48 ].…”

“…Using a sterile cotton swab, 10 μ l of the materials from every well having concentrations at and above the MICs of studied antibacterial agents was spread all over the surface of the MHA plate followed by 37°C incubation for 24 hours [ 48 ]. MBC was documented as the minimal concentration with no visible bacterial growth on MHA [ 56 ].…”

Comparative Studies on Different Extraction Methods of Centella asiatica and Extracts Bioactive Compounds Effects on Antimicrobial Activities

“…There is also the determination of the minimum inhibitory concentration (MIC) by the microdilution method using 96-well microtitration plates, the hole plate diffusion method, the two-fold method in a microtiter plate, the Versa Max Tunable microplate reader, and particular MIC methods such as the tetrazolium microplate method, liquid dilution method, and serial dilution method [ 80 ]. In terms of MIC, concentrations of extracts are varied in the preferred antimicrobial test to determine the lowest concentration of extract that effectively prevents microbial growth [ 81 ].…”

Transcriptome sequencing revealed the influence of blue light on the expression levels of light-stress response genes in Centella asiatica

“…It shows several biological activities that are pharmaceutically and cosmetically useful [ 2 , 3 ]. The extracts from this plant have been reported to have wound healing [ 4 ], antioxidant [ 5 ], anti-inflammatory [ 6 ], antibacterial [ 7 ], anticancer [ 8 ], and neuroprotective [ 9 ] activities. C .…”