Rosmarinic acid-rich ethanolic extract of Orthosiphon stamineus ameliorates cognitive and hippocampal long-term potentiation in chronic cerebral hypoperfusion rat model


  • Zurina Hassan Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.
  • KKesevan Rajah Kumaran Malaysian Institute of Pharmaceuticals and Nutraceuticals, National Institutes of Biotechnology Malaysia, Halaman Bukit Gambir, 11700 Gelugor, Pulau Pinang, Malaysia.
  • Nelson Jeng-Yeou Chear Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.
  • Siti Najmi Syuhadaa Bakar Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia.
  • Thaarvena Retinasamy Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
  • Saatheeyavaane Bhuvanendran Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
  • Amin Malik Abdul Majeed School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia.
  • Mohd. Farooq Shaikh Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
  • Iekhsan Othman Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.



O. stamineus, passive avoidance task, Morris-water-maze, cognitive function, chronic cerebral hypoperfused rats


Chronic cerebral hypoperfusion (CCH) is one of the main causes of vascular dementia caused by the reduced blood flow to the brain. Orthosiphon stamineus (OS) is a medicinal herb exhibiting pronounced neuroprotective, anti-oxidant and anti-inflammatory activities due to its high rosmarinic acid content. This study investigated the nootropic effect of OS ethanolic extract on cognitive functions in CCH rats. CCH was developed by permanent bilateral occlusion of the common carotid artery (PBOCCA). Passive avoidance task (PAT) and Morris water maze (MWM) test were conducted to evaluate cognitive functions followed by in vivo long-term potentiation (LTP) for assessing neuroplasticity. The rosmarinic acid content of OS ethanolic extract was quantified using a validated HPLC-PDA. Treatment with OS ethanolic extract significantly increased step-through latency in the PAT, decreased escape latency at a low dose of OS extract in the MWM and rescued the LTP impairment at the highest dose in CCH rats. These results strongly support the effectiveness of rosmarinic acid-rich OS extract (5.088 % w/w) in treating pathological vascular dementia caused by CCH.


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How to Cite

Hassan, Z., Kumaran, K. R., Chear, N. J.-Y., Syuhadaa Bakar, S. N., Retinasamy, T., Bhuvanendran, S., Abdul Majeed, A. M., Shaikh, M. F. and Othman, I. (2023) “Rosmarinic acid-rich ethanolic extract of Orthosiphon stamineus ameliorates cognitive and hippocampal long-term potentiation in chronic cerebral hypoperfusion rat model”, Neuroscience Research Notes, 6(3), pp. 196.1–196.16. doi: 10.31117/neuroscirn.v6i3.196.