ABSTRACT
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 A 2 (PLA 2) 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 PLA 2 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 (IC 50: 0.287 mg/mL) and was non-cytotoxic to normal HDFn cells (IC 50 >100 μg/mL). Moreover, Alstonia parvifolia was favorably cytotoxic to MCF-7 (IC 50: 4.42 μg/mL), followed by H69PR, HT-29, and THP-1, with IC 50 values of 4.94, 5.07, and 6.27 μg/mL, respectively. Alstonia parvifolia also displayed notable inhibition against PLA 2 activity of Naja philippinensis Taylor venom with IC 50 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 PLA 2 homologues where the utmost affinity was detected in HPT owing to the dipole interactions with amino acid residues. Conclusions: The bark extract of Alstonia parvifolia shows great potential as an anti-venom agent due to its low cytotoxic profile, remarkable PLA 2 inhibition, and docking binding energies between its bioactive constituents and PLA 2 homologues.
ABSTRACT
The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.
ABSTRACT
The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.
ABSTRACT
A novel method was established for the qualitative and quantitative determination of fatty acids in Channel Catfish muscle by gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) after supercritical carbon dioxide fluid extraction (SFE-CO_2). The extraction parameters for the methodology were optimized). The optimal conditions were extraction pressure of 25 MPa at 45 ℃ and extraction time of 100 min at the rate of carbon dioxide 30 L/h. The fatty acids in the muscle oil were derived by boron-trifluoride method). The saponification time was 10 min, and the esterication time was 20 min. The obtained fatty acid methylesters were separated by gas chromatography using a HP-Innowax capillary column, and were detected by electron) ionization) mass spectrometry. Full scan mode and SIM mode were used for the qualitative and quantitative analysis), respectively. In the SIM mode, saturated fatty acids were determined with m/z 74, mono-unsaturated) fatty acids were determined with m/z 55, double-unsaturated fatty acids were determined with m/z 67, and polyunsaturated fatty acids were determined with m/z 79. The detection limits of 14 fatty acids were 2.2-20.0 μg/L(S/N=3)), and the quantitative limits were 7.39-59.85 μg/L(S/N=10). The recoveries fell in the range from 90.0% to 111.2%(n=4), and the relative standard deviation was between) 2.0% and 5.9%. This effective, sensitive and reproducible method can be used for the determination of fatty acids in Channel Catfish muscle sample.