Introduction
The problem of multi-resistant bacteria to antimicrobial drugs has increased the need for new antibiotics or modifications of older antibiotics. Plants can regarded as safe and alternative source of bioactive compounds whit antimicrobial activity (Poongothai & Rajan, 2013). The beneficial medicinal effects of plant materials typically result from the combinations of secondary products present in the plant, such as alkaloids, steroids, tannins and phenol compounds (Karumanchi et al., 2016).
In this context, “mango” tree (Mangifera indica L.) is a known and widely used for treatment of several bacterial, hongs and virus infections. Many researches about antioxidant capacity and antimicrobial activity of extracts from different parts of mango tree are available, these due to high phenolic content (Masud, 2016). Characterization of polyphenolic compounds shows flavonoids like quercetin, kaempferol, phenolic acids, galloyl glycosides, abundant amounts gallic acid and mangiferin (Raju et al., 2019).
The seed extracts of mango could be activity against many microorganism pathogenic as such Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, Aspergillus niger, Candida albicans (Raju et al., 2019;5, Vega-Vega et al., 2015; Ahmed, 2015; Noguera-Machado et al., 2017). Mango seed is abundant source of polyphenols, antioxidants, flavonoids, etc. Have been detected seed mango vr. Kent presents 3.727 mg Gallic Acid Equivalent (GAE) for 100 g of fresh weight, which is higher than that reported in the pulp 48.84 mg GAE/100 g, respectively (Ayala-Zavala et al., 2010).
Staphylococcus aureus is one of the most common pathogenic bacteria, which can invade the body and cause a wide range of diseases such as skin infections and food poisoning. Due to excess use of lactam drugs, multidrug-resistant Staphylococcus aureus, especially the methicillin-resistant S. aureus (MRSA), became a high risk for the health human (Hu et al., 2019). As MRSA can produce enterotoxin and α-pore- forming toxin, it can cause skin infection and respiratory disease. MRSA is resistant to many antibiotics, not only methicillin, but also macrolide antibiotics, aminoglycoside antibiotics, so MRSA shows multiple antibiotics resistance (Lin et al., 2018).
For these reason, in this work has been investigated the antimicrobial activity of mango seeds extract against S. aureus mutants strain MRSA-1025 and MRSA- 1920.
Materials and Methods
Bacterial Strain
S. aureus MRSA 1025 and MRSA 1920 were isolated for Bastidas et al., 2020 and donated for Integral Clinical Department of the School of Bioanalysis, Carabobo University.
Preparation of mango seed extract
The variety used was “mango” “Bocado”. The seeds were collect manually from mango fruits, washed thoroughly with water to remove the pulp and then dried in hot air oven at 60°C until constant weight. The seeds were grinded by using grinder until became powder (Noguera-Machado et al., 2019).
Estimation of total phenol content (TPC)
The total phenol content was determined by Folin-Ciocalteu chloride method, whit modifications (Noguera-Machado et al., 2019), and expressed in terms of gallic acid equivalent (mg/g).
Estimation of total flavonoids (TF)
The total flavonoid content was determined methodology used by (Pacheco et al., 2018) and expressed in terms of catequine equivalent (mg/g).
Determination of antibacterial activity
Antibacterial effect were test on Mueller-Hinton agar by disc diffusion method (Noguera-Machado et al., 2017). Was probed the extract of mango seeds in four concentrations 100, 50, 25 y 12.5 mg/ mL against strains MSRA of S. aureus. How negatives controls were used the ethanol (90%) and Oxacillin antibiotic. The
Vancomycin antibiotic was the positive control.
The extract and controls were incorporate in paper dishes of 5 mm, which were bored onto the Mueller Hinton agar plates, which have inoculated whit strains. After 24 h at 37°C incubation, the plates were observed for the results and zone of inhibitions measured. The experiment was done in triplicate and values are presented as Mean ± SD.
Results and Discussion
Phytochemical constituents of extracts (TPC, TF)
The total phenolic and flavonoids contents of extract were higher, comparative whit the values reported for Ayala-Zabala et al. 2010. This difference probably due for variety utilized, in this work “Bocado” (Table 1).
Antibacterial Activity
The result revealed that the extracts of M. indica seed possess good antibacterial activity against strain probed. For strain S. aureus MRSA 1025 and 1920, the inhibition zones ranged from 6.0 mm to 19 mm, at different concentration extracts probed. Were observed on dependent effect doses in function of extract concentration, whereas major concentration more zone inhibition.
The Oxacillin and ethanol showed minimal inhibition (6.0 ± 1.0 mm). The Vancomycin (positive control) exhibited the maxima inhibition of 19.7 ± 0.6 mm (Table 2).
The maxima concentration of extracts produced zone inhibition of 16.7 ± 2.5 mm, near value of positive control (Vancomycin), indicative the sensibility to extract. Additionally, these finding coincide of Ahmed, (2015), who reported zone inhibition of 20 mm whit mango seeds ethanol extract against S. aureus. Additionally, these value resulted higher than the zone inhibition described for El- Gied et al. (2012), enter 8 and 13 mm, for S. aureus MRSA clinical isolate.
Conclusion
Plant and fruits derived products are potential sources of novel antimicrobial compounds especially against bacterial pathogens. In this work showed that, the extractions of mango seeds bioactive compounds whit ethanol solvent, is efficient and to have advantage for considered to safe and nontoxic in bio treatments. Moreover, present study probed that the mango seed extract contained many compounds such as phenolic that could be affect bacteria S. aureus MRSA. These bioactive compounds to be isolated so that they can serve as templates for the production of new antibiotics.