Assessment of Pharmacological Potential of Novel Exopolysaccharide Isolated from Marine Kocuria sp. Strain AG5: Broad-Spectrum Biological Investigations

Samar Zuhair Alshawwa, Khalid S. Alshallash, Ahmed Ghareeb, Ahmed M. Elazzazy, Mohamed Sharaf, Afaf Alharthi, Fathy Elsayed Abdelgawad, Dalia El-Hossary, Mariusz Jaremko, Abdul Hamid Emwas, Yosra A. Helmy

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


With more than 17 clinically approved Drugs and over 20 prodrugs under clinical investigations, marine bacteria are believed to have a potential supply of innovative therapeutic bioactive compounds. In the current study, Kocuria sp. strain AG5 isolated from the Red Sea was identified and characterized by biochemical and physiological analysis, and examination of a phylogenetic 16S rRNA sequences. Innovative exopolysaccharide (EPS) was separated from the AG5 isolate as a major fraction of EPS (EPSR5, 6.84 g/L−1). The analysis of EPSR5 revealed that EPSR5 has a molecular weight (Mw) of 4.9 × 104 g/mol and number average molecular weight (Mn) of 5.4 × 104 g/mol and contains sulfate (25.6%) and uronic acid (21.77%). Analysis of the monosaccharide composition indicated that the EPSR5 fraction composes of glucose, galacturonic acid, arabinose, and xylose in a molar ratio of 2.0:0.5:0.25:1.0, respectively. Assessment of the pharmacological potency of EPSR5 was explored by examining its cytotoxicity, anti-inflammatory, antioxidant, and anti-acetylcholine esterase influences. The antioxidant effect of EPSR5 was dose- and time-dependently increased and the maximum antioxidant activity (98%) was observed at 2000 µg/mL after 120 min. Further, EPSR5 displayed a significant repressive effect regarding the proliferation of HepG-2, A-549, HCT-116, MCF7, HEP2, and PC3 cells with IC50 453.46 ± 21.8 µg/mL, 873.74 ± 15.4 µg/mL, 788.2 ± 32.6 µg/mL, 1691 ± 44.2 µg/mL, 913.1 ± 38.8 µg/mL, and 876.4 ± 39.8 µg/mL, respectively. Evaluation of the inhibitory activity of the anti-inflammatory activity of EPSR5 indicated that EPSR5 has a significant inhibitory activity toward lipoxygenase (5-LOX) and cyclooxygenase (COX-2) activities (IC50 15.39 ± 0.82 µg/mL and 28.06 ± 1.1 µg/mL, respectively). Finally, ESPR5 presented a substantial hemolysis suppressive action with an IC50 of 65.13 ± 0.89 µg /mL, and a considerable inhibitory activity toward acetylcholine esterase activity (IC50 797.02 μg/mL). Together, this study reveals that secondary metabolites produced by Kocuria sp. strain AG5 marine bacteria serve as an important source of pharmacologically active compounds, and their impact on human health is expected to grow with additional global work and research.

Original languageEnglish
Article number1387
Issue number9
StatePublished - Sep 2022

Bibliographical note

Funding Information:
This research was funded by Faculty of Pharmacy, Suez Canal University, Egypt. This research was also funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R165), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Publisher Copyright:
© 2022 by the authors.


  • 5-LOX
  • COX-2
  • FTIR
  • Kocuriasp
  • acetylcholine esterase activity
  • antioxidant
  • cytotoxicity
  • exopolysaccharide
  • marine drugs
  • natural products
  • secondary metabolites

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Biochemistry, Genetics and Molecular Biology (all)
  • Space and Planetary Science
  • Paleontology


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