Effects of a Proprietary Standardized Orthosiphon stamineus Ethanolic Leaf Extract on Enhancing Memory in Sprague Dawley Rats Possibly via Blockade of Adenosine A_2A Receptors

Table 5

Results of in vitro adenosine A_2A and adenosine A₁ assays.

Assay	Concentration (g/mL)	Inhibition (%)	IC50 (g/mL)
Adenosine A2A binding assay	15	17	60.07
	150	74
Adenosine A2A functional assay antagonist	3	14	51.5
	30	26
	300	98
		Increase in cAMP (%)
Adenosine A2A functional assay agonist	3	−1	—
	30	−3
	300	−8
Adenosine A1 functional assay antagonist activity	3	0	95.1
	30	0
	300	100
		Reduction in neurogenic twitch (%)
Adenosine A1 functional assay agonist activity	3	5	—
	30	12
	300	29