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. 2018 Dec 7;18(1):325.
doi: 10.1186/s12906-018-2382-7.

Terminalia bellirica fruit extracts: in-vitro antibacterial activity against selected multidrug-resistant bacteria, radical scavenging activity and cytotoxicity study on BHK-21 cells

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Terminalia bellirica fruit extracts: in-vitro antibacterial activity against selected multidrug-resistant bacteria, radical scavenging activity and cytotoxicity study on BHK-21 cells

M Priyanga Jayamal Dharmaratne et al. BMC Complement Altern Med. .

Abstract

Background: Identification of novel sources for developing new antibiotics is imperative with the emergence of antibiotic resistant bacteria. The fruits of Terminalia bellirica (Gaertn) Roxb., widely used in traditional medicine, were evaluated for antibacterial activity against multidrug-resistant (MDR) bacteria, antioxidant activity and cytotoxicity.

Methods: Twelve solvent extracts of T. bellirica fruits were prepared by direct aqueous extraction and sequential extraction with dichloromethane, methanol and water using Soxhlet, bottle-shaker and ultrasound sonicator methods. Antibacterial activity of the extracts was tested against 16 strains MDR bacteria-methicillin-resistant Staphylococcus aureus (MRSA), extended spectrum β-lactamase (ESBL) producing Escherichia coli and MDR Acinetobacter spp., Klebsiella pneumoniae and Pseudomonas aeruginosa-and 4 control organisms, using the cut-well diffusion method. The minimum inhibitory concentration (MIC) was determined using an agar dilution method. The radical scavenging activity of six antibacterial extracts was screened against 2,2'-diphenyl-2-picrylhydrazyl (DPPH) and correlation was established between EC50 (50% effective concentration) values and the total phenolic content (TPC). Cytotoxicity was determined for the most potent antibacterial extract on baby hamster kidney (BHK-21) cells by Tryphan Blue exclusion method. Statistical analysis was carried out by one-way analysis of variance at significant level p < 0.05 using "SigmaPlot 10" and "R 3.2.0" software.

Results: All aqueous and methanol extracts displayed antibacterial activity (MIC 0.25-4 mg/mL) against all strains of MRSA, MDR Acinetobacter spp. and MDR P. aeruginosa. The sequential aqueous extracts (MIC, 4 mg/mL) inhibited ESBL producing-E. coli. None of the extracts exhibited activity against MDR K. pneumoniae (MIC > 5 mg/mL). The sequential methanol extract (Soxhlet) recorded high antibacterial activity and the highest DPPH radical scavenging activity (EC50, 6.99 ± 0.15 ppm) and TPC content (188.71 ± 2.12 GAE mg/g). The IC50 (50% inhibition concentration) values of the most potent antibacterial extract-the direct aqueous extract from reflux method-on BHK-21 cells were 2.62 ± 0.06 and 1.45 ± 0.08 mg/ml with 24 and 48 h exposure, respectively.

Conclusions: Results indicate that T. bellirica fruit is a potential source for developing broad-spectrum antibacterial drugs against MDR bacteria, which are non-toxic to mammalian cells and impart health benefits by high antioxidant activity.

Keywords: Antibacterial; Antioxidant; BHK-21 cells; Multidrug-resistant bacteria; Terminalia bellirica; Total phenolic content.

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Figures

Fig. 1
Fig. 1
An overview of different methods used for extracting dried pericarp of Terminalia bellirica fruit
Fig. 2
Fig. 2
Mean diameter of zones of inhibition (ZOI) for direct aqueous extracts (10 mg/mL) of Terminalia bellirica prepared from reflux method, bottle-shaker method and ultrasound sonication method
Fig. 3
Fig. 3
Mean diameter of zones of inhibition (ZOI) for sequential methanol extracts (10 mg/mL) of Terminalia bellirica prepared from Soxhlet method, bottle-shaker method and ultrasound sonication method
Fig. 4
Fig. 4
Mean diameter of zones of inhibition (ZOI) for sequential aqueous extracts (10 mg/mL) of Terminalia bellirica prepared from reflux method, bottle-shaker method and ultrasound sonication method
Fig. 5
Fig. 5
DPPH radical scavenging activity (EC50 value) of ascorbic acid and Terminalia bellirica extracts (Sample: Asc, Ascorbic acid; DaqR, direct aqueous extract from reflux method; DaqB, direct aqueous extract from bottle-shaker method; DaqU, direct aqueous extract from ultrasound sonication method; SmeS, sequential methanol extract from Soxhlet method; SmeB, sequential methanol extract from bottle-shaker method; SmeU, sequential methanol extract from ultrasound sonication method)
Fig. 6
Fig. 6
Relationship between total phenolic content (TPC in gallic acid equivalents, GAE) and EC50 values of DPPH scavenging activity

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References

    1. Prestinaci F, Pezzotti P, Pantosi A. Antimicrobial resistance: a global multifaceted phenomenon. Pathog Glob Health. 2015;109:309–318. doi: 10.1179/2047773215Y.0000000030. - DOI - PMC - PubMed
    1. World Health Organization. Antimicrobial resistance: global report on surveillance. Geneva, WHO; 2014. http://apps.who.int/iris/bitstream/10665/112642/1/9789241564748eng.pdf. Accessed 28 Aug 2017.
    1. Woodford N, Livermore DM. Infections caused by Gram-positive bacteria: a review of the global challenge. J Inf Secur. 2009;59(S1):S4–16. - PubMed
    1. Hatcher JC, Dhillon R, Azadian B. Antibiotic resistance mechanisms in the intensive care unit. J Intensive Care Soc. 2012;13:298–302. doi: 10.1177/175114371201300407. - DOI
    1. World Health Organization . Global priority list of antibiotic-resistant bacteria to guide research, discovery, and development of new antibiotics. Geneva: WHO; 2017.