Bioactive Phenylethanoids from the Seeds of Manilkara zapota

Aims: Discovering new lead compounds against cancer and bacterial infections is a crucial step to ensuring a sustainable global pipeline for new effective drugs. These study focuses on the isolation of secondary metabolites of methanol extract from the seeds of Manilkara zapota (Sapotaceae) a Cameroonian medicinal plant.

Study Design: According to the literature, plants of the genus Manilkara are potential sources of antibacterial and anticancer secondary metabolites.

Methodology: The air-dried and powdered seeds (1.8 kg) of M. zapota was extracted at room temperature for 72 h with a mixture of CH2Cl2/methanol (1/1). The extract was concentrated to dryness under vacuum and the residue was subjected to repeated column chromatographic separation. The structures of the isolates were established by means of spectroscopic methods. These compounds were screened in vitro for their free radical scavenging activity using DPPH.

Results: New phenylethanoid, 2-(4-hydroxyphenethyl) tetratriacontanoate (1), together with twelve known compounds were isolated from the CH2Cl2/methanol (1/1) extract from the seeds of Manilkara zapota. The structures of all compounds were determined by comprehensive analysis of their 1D and 2D NMR, mass spectral (EI and ESI) data, chemical reactions and comparison with previously known analogs. The radical scavenging activity using DPPH assay gave significantly high antioxidant values for the crude extract with IC508.50 μg/mL, and moderate activity for the phenylethanoid compounds 1-6 with IC50 62.52- 70.20 mM compared to the phenolic synthetic antioxidant standard BHA with IC50 44.20 mM.

Conclusion: Six phenylethanoids with moderate antioxidant activity were isolated from the seeds of Manilkara zapota.