Effects of different parts of Boswellia dalzielii Hutch extracts on key enzymes associated with brain function – in vitro

BACKGROUND: Boswellia dalzielii (B. dalzielii) is traditionally used in African ethnomedicine to manage neurological and cognitive disorders. This study investigated the in vitro effects of its leaf, stem bark, and root bark extracts on key enzymes associated with brain function. METHODS: The leaf, stem bark, and root bark were air-dried, powdered, and extracted using water. The concentrated extracts were evaluated for their effects on acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), monoamine oxidase (MAO), ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase), ecto-5'-nucleotidase, and Na⁺/K⁺-ATPase activities following standard in vitro protocols. RESULTS: The extracts exhibited concentration-dependent inhibition of AChE, BuChE, MAO, E-NTPDase, and ecto-5'-nucleotidase, as well as modulation of Na⁺/K⁺-ATPase activity. The stem bark extract showed the strongest inhibition of AChE and BuChE, with markedly lower IC₅₀ values (27.92 ± 1.45 and 32.20 ± 1.51 µg/mL for AChE and BuChE, respectively) than the leaf and root bark extracts and comparable potency to the standard inhibitor, Prostigmine. For MAO, the root bark extract displayed the highest inhibitory activity (IC₅₀ = 70.92 ± 1.88 µg/mL), followed by the leaf and stem bark extracts. The stem bark extract also exhibited the most potent inhibition of E-NTPDase (IC₅₀ = 31.71 ± 1.50 µg/mL for ATP and 42.01 ± 1.62 µg/mL for ADP) and ecto-5'-nucleotidase (IC₅₀ = 41.20 ± 1.62 µg/mL), while moderately enhancing Na⁺/K⁺-ATPase activity. Overall, the stem bark extract displayed the greatest enzyme modulatory capacity among the plant parts tested. Phytochemical profiling revealed the presence of stilbenoids in all plant parts. CONCLUSIONS: These in vitro findings demonstrate that B. dalzielii extracts can modulate the activity of key enzymes related to brain function. Further in vivo and in silico investigations are underway to elucidate the pharmacological and neuroprotective relevance of these effects.