title: 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.
abstract: The aim of the study was to explore a propriety standardized ethanolic extract from leaves of Orthosiphon stamineus Benth in improving impairments in short-term social memory in vivo, possibly via blockade of adenosine A2A receptors (A2AR). The ethanolic extract of O. stamineus leaves showed significant in vitro binding activity of A2AR with 74% inhibition at 150 μg/ml and significant A2AR antagonist activity with 98% inhibition at 300 μg/mL. A significant adenosine A1 receptor (A1R) antagonist activity with 100% inhibition was observed at 300 μg/mL. Its effect on learning and memory was assessed via social recognition task using Sprague Dawley rats whereby the ethanolic extract of O. stamineus showed significant (p < 0.001) change in recognition index (RI) at 300 mg/kg and 600 mg/kg p.o and 120 mg/kg i.p., respectively, compared to the vehicle control. In comparison, the ethanolic extract of Polygonum minus aerial parts showed small change in inflexion; however, it remained insignificant in RI at 200 mg/kg p.o. Our findings suggest that the ethanolic extract of O. stamineus leaves improves memory by reversing age-related deficits in short-term social memory and the possible involvement of adenosine A1 and adenosine A2A as a target bioactivity site in the restoration of memory.
authors.affiliation: Biotropics Malaysia Berhad, Lot 21 Jalan U1/19, Section U1, Hicom-Glenmarie Industrial Park, 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Annie
authors.identifier: 0000-0001-6806-018X
authors.initials: A
authors.lastname: George
authors.affiliation: Biotropics Malaysia Berhad, Lot 21 Jalan U1/19, Section U1, Hicom-Glenmarie Industrial Park, 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Sasikala
authors.identifier: 0000-0002-7917-872X
authors.initials: S
authors.lastname: Chinnappan
authors.affiliation: Ethix Pharma Laboratories, Karbala Road, Bilaspur 495001, Chhattisgarh, India.
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Choudhary
authors.affiliation: Ethix Pharma Laboratories, Karbala Road, Bilaspur 495001, Chhattisgarh, India.
authors.forename: Vandana Kotak
authors.initials: VK
authors.lastname: Choudhary
authors.affiliation: Ethix Pharma Laboratories, Karbala Road, Bilaspur 495001, Chhattisgarh, India.
authors.forename: Praveen
authors.initials: P
authors.lastname: Bommu
authors.affiliation: Biotropics Malaysia Berhad, Lot 21 Jalan U1/19, Section U1, Hicom-Glenmarie Industrial Park, 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Hoi Jin
authors.initials: HJ
authors.lastname: Wong