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Purpose: To evaluate the anti-oxidant, anti-inflammatory and anti-acetylcholine esterase activities of betulinic acid (BA) and 3β- acetoxybetulinic acid (BAA) from Melaleuca bracteata. ‘Revolution Gold’.
Methods: Betulinic acid was isolated from the ethyl acetate extract of M. braceteata while BAA was synthesized by acetylation of BA. Structural elucidation of the compounds was achieved by spectroscopic methods. Antioxidant potential was determined using superoxide dismustase (SOD) and catalase assay kits while iron chelation activity assessed with ferrozin. Anti-inflammatory activity was determined using cotton pellet-induced granuloma rat model. Cyclooxygenase (COX) activity evaluated by COX kits; acetylcholine kit was used for anti-acetylcholinesterase (ACHE) study.
Results: The compounds significantly (p < 0.05) dose-dependently inhibited ACHE and inflammatory activity. They also significantly decreased the inhibition of SOD, catalase activity but increased iron chelation activities in a dose-dependent manner. However, BAA showed higher activity than BA for all the parameters. BAA also had a greater inhibitory effect on COX-2 than on COX-1. BAA (IC50, 0.88 mg/mL) showed better iron chelation than citric acid (0.96 ± 0.04) and EDTA (1.04 ± 0.03), the positive control.
Conclusion: BA and BAA possess anti-ACHE, anti-inflammatory, antioxidant and anti-COX activities. Structural modification of BAA influences its biological activities. Therefore, BAA can potentially serve as a scaffold in synthesizing potent neurodegeneration drugs.
Keywords: Betulinic acid, 3β-Acetoxybetulinic acid, Antioxidant, Anti-inflammatory, Antiacetylcholinesterase, Melaleuca bracteata. ‘Revolution Gold’