Title:Hemisynthesis of Pentacyclic Triterpenoids from Diospyros foxworthyi with In vitro
and In silico Anti-malarial Evaluation
Volume: 28
Issue: 10
Author(s): Muhammad Solehin Abd Ghani, Nur Ain Latifhaa Abu Bakar, Arba Pramundita Ramadani, Arde Toga Nugraha, Khalijah Binti Awang, Mohammad Tasyriq Che Omar, Unang Supratman, Ezatul Ezleen Kamarulzaman and Mohamad Nurul Azmi Mohamad Taib*
Affiliation:
- Natural Products and Synthesis Organic Laboratory (NPSOLab), School of Chemical Sciences, Universiti Sains Malaysia, Minden
11800, Penang, Malaysia
Keywords:
Pentacyclic triterpenoids, hemisynthesis, anti-malaria, β-hematin inhibition activity, molecular docking, Diospyros foxworthyi.
Abstract: A total of twelve pentacyclic triterpenoid derivatives based on betulin (1) and lupeol (2) scaffolds
isolated from Diospyros foxworthyi were hemisynthesized by acylation or acetylation reactions with appropriate
acid chloride or acetic anhydride. The structures of the hemisynthesised compounds were characterised by
means of FT-IR, 1D- and 2D-NMR, as well as HRMS analysis. These compounds were assayed for in vitro
anti-malarial studies by inhibition of β-hematin formation assay with chloroquine as a positive control. Compounds
1d and 2f showed the strongest potential as β-hematin formation inhibitors with IC50 values of 6.66 ±
1.36 and 11.89 ± 0.15 μM, respectively, compared with the positive control (chloroquine; IC50 = 37.50 ± 0.60
μM). In silico molecular docking simulations were performed using AutoDock Vina for compounds 1d and 2f
to investigate the binding interactions and free energy of binding (FEB) with the hemozoin supercell crystal
structure (CCDC number: XETXUP01). The findings revealed several hydrophobic interaction modes between
the 1d, 2f and hemozoin, with calculated FEBs of -8.4 ± 0.2 and -8.9 ± 0.0 kcal mol-1, indicating strong and
favourable interactions.