Abstract
Bacterial infection is one of the most prevalent infectious diseases in the world, and the search for innovative antibacterial agents from medicinal plants to combat microbial infection has remained a vital aspect of antimicrobial drug discovery [1, 2]. Till date, bacterial infections are treated with a combination of various medicinal plants in most developing countries which could show that plants have potential as sources of antibacterial extracts and compounds [3].
Salix species commonly called willows are a group of plants that belong to the Salicaceae family. The bark of Salix species (willow bark) is known to be traditionally used in the treatment of inflammation, high fever and pain [4].
In this study, the antibacterial activity of the methanol, cold water maceration, and hot water decoction of the twig extracts of Salix aurita, Salix caprea and Salix pyrolifolia were tested against Gram-positive and Gram-negative human pathogenic bacterial strains. Agar diffusion and microplate methods were used to evaluate the antibacterial activity of the extracts. Salicin, salicortin, taxifolin and other pure compounds present in Salix were also screened for their antibacterial activity. UPLC-PDA-QTOF/MS (ESI- mode) was used for the chemical identification and molecular mass determination of the bioactive compounds present in the extracts. All twig extracts of S. aurita, S. caprea and S. pyrolifolia were active against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus with the cold-water maceration of S. caprea showing the highest percentage of growth inhibition against P. aeruginosa and a methanol extract of S. aurita showed good growth inhibition against B. cereus. The minimum inhibitory concentration values ranged from 1250 to 2500 µg/mL. S. caprea
water extracts showed strong growth inhibition of both S. aureus and B. cereus (IZD 28.3 mm). The extracts were not active against Escherichia coli except the hot water decoction of S. aurita and a cold-water maceration of S. caprea which showed inhibition zones of 18.3 and 22.0 mm, respectively. Salicin was moderately active against P. aeruginosa and S. aureus with an inhibition zone of 19.0 mm for both. In a time- kill assay of a cold methanol extract of the twigs
of S. aurita against B. cereus, the extracts at MIC and 0.5 MIC inhibited totally the growth of this bacterium at all time-points till 24-hour incubation. UPLC-PDA-QTOF/MS results showed that the extracts contained salicylates, procyanidins and flavonoids as their major compounds. The results from the findings indicate that Salix aurita, Salix caprea and Salix pyrolifolia are
good sources of antibacterial compounds that could have potential as antibacterial agents’ scaffolds.
[1] U. Anand et al. Metabolites 9(11):258, (2019).
[2] G. Porras et al. Chemical Reviews 121(6):3495-3560, (2020).
[3] N. Talukdar et al. Journal of Diabetology 12(2):128-133, (2021).
[4] E. Gligorić et al. Sustainable Chemistry and Pharmacy 32:00981, (2023).
Salix species commonly called willows are a group of plants that belong to the Salicaceae family. The bark of Salix species (willow bark) is known to be traditionally used in the treatment of inflammation, high fever and pain [4].
In this study, the antibacterial activity of the methanol, cold water maceration, and hot water decoction of the twig extracts of Salix aurita, Salix caprea and Salix pyrolifolia were tested against Gram-positive and Gram-negative human pathogenic bacterial strains. Agar diffusion and microplate methods were used to evaluate the antibacterial activity of the extracts. Salicin, salicortin, taxifolin and other pure compounds present in Salix were also screened for their antibacterial activity. UPLC-PDA-QTOF/MS (ESI- mode) was used for the chemical identification and molecular mass determination of the bioactive compounds present in the extracts. All twig extracts of S. aurita, S. caprea and S. pyrolifolia were active against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus with the cold-water maceration of S. caprea showing the highest percentage of growth inhibition against P. aeruginosa and a methanol extract of S. aurita showed good growth inhibition against B. cereus. The minimum inhibitory concentration values ranged from 1250 to 2500 µg/mL. S. caprea
water extracts showed strong growth inhibition of both S. aureus and B. cereus (IZD 28.3 mm). The extracts were not active against Escherichia coli except the hot water decoction of S. aurita and a cold-water maceration of S. caprea which showed inhibition zones of 18.3 and 22.0 mm, respectively. Salicin was moderately active against P. aeruginosa and S. aureus with an inhibition zone of 19.0 mm for both. In a time- kill assay of a cold methanol extract of the twigs
of S. aurita against B. cereus, the extracts at MIC and 0.5 MIC inhibited totally the growth of this bacterium at all time-points till 24-hour incubation. UPLC-PDA-QTOF/MS results showed that the extracts contained salicylates, procyanidins and flavonoids as their major compounds. The results from the findings indicate that Salix aurita, Salix caprea and Salix pyrolifolia are
good sources of antibacterial compounds that could have potential as antibacterial agents’ scaffolds.
[1] U. Anand et al. Metabolites 9(11):258, (2019).
[2] G. Porras et al. Chemical Reviews 121(6):3495-3560, (2020).
[3] N. Talukdar et al. Journal of Diabetology 12(2):128-133, (2021).
[4] E. Gligorić et al. Sustainable Chemistry and Pharmacy 32:00981, (2023).
| Original language | English |
|---|---|
| Title of host publication | NNPC2023 – Nordic Natural Products Conference 2023 |
| Number of pages | 1 |
| Publication date | 14 Jun 2023 |
| Pages | 54-54 |
| Publication status | Published - 14 Jun 2023 |
| MoE publication type | A4 Article in conference proceedings |