Zoology
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Item "Inhibition of phospholipase A2 from Naja haje and Naja nigricollis venoms by active fraction of Moringa oleifera leaves: in vitro and in silico methods"(Taylor & Francis, 2023) Adeyi, A.O.; Jimoh, A.O.; Ajisebiola, B.S.; Adeyi, O.E.; Metibemu, D.S.; Okonji, P.E.Phospholipases are one of the principal toxic enzymes in snake venoms inducing a wide variety of pharmacological effects after envenomation. Natural inhibitors from plants are known to inhibit the toxic enzyme activities of snake venoms. In this study, ethanol crude extract of M. oleifera leaves was partitioned using n-hexane and ethyl acetate after which fractionation was done using column and thin layer chromatography. Subsequently, the inhibitory activities of the crude extract and sub-fractions of M. oleifera were investigated against phospholipases A2 isolated from Naja haje and Naja nigricollis venoms using in vitro and in-silico approaches while EchiTab-PLUS polyvalent antivenom was used as the standard drug. The molecular weight of isolated N. haje phospholipase A2 (NH-PL) and N. nigricollis phospholipase A2 (NN-PL) were 24.11 and 35.22 kDa respectively. NH-PL enzyme had a specific activity of 2.70 lM/min/mg substrate while NN-PL activity was 2.10 lM/min/mg substrate. The Km of NH-PL was 0.330 lM with Vmax of 0.085 lM/mL min while NN-PL had Vmax of 0.198 lM/mL.min and Km of 0.670 lM. M. oleifera nhexane sub-fraction 5 (MOLH5) exhibited a total inhibition of NN-PL and NH-PL enzyme activities at all concentrations used. Molecular docking of the phytoconstituents of MOLH5 against the catalytic site of phospholipase A2 revealed 2-Hydrazino-8-hydroxy-4-phenylquinoline as the lead compound and a potential drug candidate with a docking score of _6.789 kcal/mol. Findings indicated that MOLH5 possesses phospholipase A2 natural inhibitors that could be explored as a therapy for snake envenoming.Item Inhibition of Echis ocellatus venom metalloprotease by flavonoid-rich ethyl acetate sub-fraction of Moringa oleifera (Lam.) leaves: in vitro and in silico approaches(Taylor & Francis, 2021) Adeyi, A.O.; Mustapha, K.K.; Ajisebiola, B.S.; Adeyi, O.E.; Metibemu, D.S.; Okonji, R.E"Envenoming by Echis ocellatus is potentially life-threatening due to severe hemorrhage, renal failure and capillary leakage. These effects are attributed to snake venom metalloproteinases (SVMPs). Due to drawbacks in the use of antivenin, natural inhibitors from plants are of interest in studies of new antivenin treatment. Antagonizing effects of bioactive compounds of Moringa oleifera is yet to be tested against SVMPs of E. ocellatus (SVMP-EO). Ethanol crude extract of M. oleifera was partitioned using n-hexane and ethyl acetate. Each partitions was fractionated using column chromatography and tested against SVMP-EO purified through ion exchange chromatography with EchiTab-PLUS polyvalent antivenin as control. Phytoconstituents of ethyl acetate fraction was screened against catalytic site of crystal of BaP1-SVMP while drug-likeness and ADMET toxicity of compound was equally determined. The molecular weight of isolated SVMP-EO was 43.28 kDa, with specific activity of 245 U/ml, percentage yield of 62.83 % and purification fold of 0.920. The Vmax and Km values are 2 mg/ml and 38.095 imol/ml/min, respectively while the optimal pH and temperature are 6.0 and 40 °C, respectively. Polyvalent antivenin, crude extract and ethyl acetate fraction of M. oleifera exhibited complete inhibitory effect against SVMP-EO activity. Inhibitions of P-1 and P-II metalloprotease's enzymes by ethyl acetate fraction are largely due to methanol, 6, 8, 9-trimethyl-4-(2-phenylethyl)-3-oxabicyclo[3.3.1]non-6-en-1-yl)- and paroxypropione, respectively. Both compounds are potential drug candidates with little or no concern of toxicity as revealed from in-silico predictions. The inhibitory effects suggest that this compound might be therapeutic candidate for further exploration for treatment of Ocellatus' envenoming."