Antioxidant, cytotoxic, and anti-venom activity of Alstonia parvifolia Merr. Bark

• Published in: Asian Pacific Journal of Tropical Biomedicine
• Main Authors: Maria Carmen S. Tan, Mary Stephanie S. Carranza, Virgilio C Linis, Raymond S Malabed, Yves Ira A. Reyes, Francisco C Franco, Glenn G Oyong
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer Medknow Publications 2021
• Subjects: alstonia parvifolia merr.; naja philippinensis taylor; gas chromatography-electron ionization-mass spectrometry; secretory phospholipase a2; cytotoxicity assay; anti-venom; Arctic medicine. Tropical medicine; RC955-962; Biology (General); QH301-705.5; Arctic
• Online Access: https://doi.org/10.4103/2221-1691.326100; https://doaj.org/article/5114d99e1a8d480b96dc1535bf929196

Objective: To evaluate antioxidant, cytotoxic, and anti-venom capacity of crude bark extracts of Alstonia parvifolia Merr. Methods: Gas chromatography-mass spectrometry (GC-MS) and energy dispersive X-ray analyses were accomplished to characterize the chemical constituents of Alstonia parvifolia. Biochemical characterization was evaluated using an inhibitory phospholipase A2 (PLA2) assay, DPPH, and cytotoxicity assays. Using the constituents listed in the GC-MS analyses, molecular docking was conducted to inspect the binding energies between the chosen compounds and selected PLA2 isoforms. Results: GC-MS analyses showed that the Alstonia parvifolia crude extract consisted predominantly of acetylmarinobufogenin (14.89%), γ-sitosterol (10.44%), 3-O-methyl-D-glucose (5.88%), 3,5-dimethoxy-4-hydroxyphenylacetic acid (5.30%), (2α,5α)-17-methoxyaspidofractinin-3-one (AFM) (4.08%), and 2,3,5,6,7,8,9-heptahydro-1-phenyl-5-(p-chlorophenylimino)-1H-benzo[e][1],[4]thiazepine (HPT) (1.37%). The principal elemental components of Alstonia parvifolia were Ca (4.012%) and K (1.496%), as exhibited by energy dispersive X-ray examination. Alstonia parvifolia showed significant free radical scavenging ability (IC50: 0.287 mg/mL) and was non-cytotoxic to normal HDFn cells (IC50 >100 μg/mL). Moreover, Alstonia parvifolia was favorably cytotoxic to MCF-7 (IC50: 4.42 μg/mL), followed by H69PR, HT-29, and THP-1, with IC50 values of 4.94, 5.07, and 6.27 μg/mL, respectively. Alstonia parvifolia also displayed notable inhibition against PLA2 activity of Naja philippinensis Taylor venom with IC50 of (15.2 ± 1.8) μg/mL. Docking and cluster analyses projected negative binding energies from AFM (-6.36 to -9.68 kcal/mol), HPT (-7.38 to -9.77 kcal/ mol), and acetylmarinobufogenin (-7.22 to -9.59 kcal/mol). These calculations were for the particular interactions of Alstonia parvifolia constituents to PLA2 homologues where the utmost affinity was detected in HPT owing to the dipole interactions with amino acid residues. Conclusions: The bark ...