Search

In the human oral cavity, Streptococcus mutans is often observed and is a major contributor to tooth decay. Increased S. mutans levels may be linked to progressively more severe forms of periodontal disease because root exposure in people with periodontitis increases caries rates. Hence, a new potential antibacterial compound needs to be searched to combat this pathogenic bacterium. The butterfly pea, or Clitoria ternatea is an ornamental plant that has been reported to exhibit antibacterial properties against several bacteria. Thus, the goal of this investigation was to determine how well C. ternatea aqueous (CTA) extract inhibited S. mutans. The disk diffusion assay was performed to access the antibacterial properties of the CTA extract. The efficiency of the extract against the test bacterium was then determined through MIC/MBC determinations and a time-kill study. Meanwhile, the toxicity of the extract was tested using a brine shrimp lethality assay (BSLA). The CTA extract demonstrated substantial antibacterial activity against the test bacterium at a concentration of 200 mg/ml, with a diameter of the inhibition zone of 13.4±0.4 mm, according to the disc diffusion assay. The aqueous extract’s MIC and MBC values were found to be 100 and 400 g/mL, respectively. Time-kill analysis revealed the CTA extract exerted a strong bactericidal effect on S. mutans and this activity was dose-dependent. A scanning electron microscope (SEM) exhibited the bacterial cells experienced severe damage after being exposed to CTA extract including formation cavities, irregular shape, and crumpled cells. Thus, the present study suggested the potential of CTA extract as an antibacterial agent against oral cavity bacteria and can be used in the formulation of natural mouthwash due to no toxicity effect.

Research on atrazine has expanded over the past decade. Studies focussing on the adverse effects of atrazine, methods for atrazine removal, and evaluation of water quality have been conducted. Atra...

The effect of incorporating plant extract in the culture medium on anti-MRSA activity of Lasiodiplodia pseudotheobromae IBRL OS-64, was investigated in the present study. On disk diffusion assay, the ethyl acetate fungal extract from culture medium supplemented with host plant extract (HPE) of Ocimum sanctum leaves demonstrated good anti-MRSA activity with a diameter inhibition zone of 22.6±0.6 mm. Meanwhile, the minimal inhibition concentration (MIC) values of the extract from YES broth and YES broth incorporated with HPE were 1000 µg/mL and 250 µg/mL, respectively. The MBC values were 8000 µg/mL and 500 µg/mL, respectively. The YES + HPE extracts exerted bactericidal effect against the test bacteria since the MBC/MIC ratio was less than or equal to 4. The time-kill study revealed a 90% of growth reduction of MRSA ATCC 33591 after 16 h exposure to the fungal extract cultured in YES + HPE. Ironically, for fungal extract grown in YES broth, time-kill curve showed a regrowth pattern of bacterial cells after 24 h exposed to the extract. Therefore, the present study suggested that the addition of HPE in the culture medium could enhance the anti-MRSA activity of endophytic fungus, L. pseudotheobromae IBRL OS-64 against MRSA ATCC 33591.

The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 log10, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GCMS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.