Datura alba seed proteins effect on snake venom enzymes with antioxidant and antibacterial activities

This study assessed the inhibitory potential of proteins extracted from Datura alba seeds on snake venom toxic enzymes along with their potential antioxidant and antibacterial activities.

Crude proteins were extracted using common biological buffers (20 mM acetate, 20 mM phosphate and 20 mM Tris) at a ratio of 1:5 followed by 80 % ammonium sulfate precipitation, dialysis, and lyophilization. Then the lyophilized extracts were resolved on 15 % sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) gels. The Tris extract showing the maximum number of protein bands on the SDS gel was further assessed for inhibitory bioactivities. Specifically, the agar well diffusion method was performed to assess the inhibitory activities of phospholipase A2 (PLA2), protease, and α-amylase using 2 % egg yolk, 5 % skim milk and 1 % starch as substrates, respectively. Naja naja, Echis carinatus venom, and human saliva were used as sources of PLA2, protease, and amylase, respectively, to test the inhibitory activity of the extract on these enzymes. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay using ascorbic acid as a standard. Antibacterial activity was assessed by the agar well diffusion method using Escherichia coli and Staphylococcus aureus as bacterial sources.

The Tris extract of seed proteins exhibited 19 % inhibition of snake venom PLA2 at a concentration of 125 μg/μL concentration, whereas no venom protease inhibition or antibacterial activity was observed at the highest concentrations analyzed. Significant antioxidant activity (44.9 %) was observed at 600 μg/μL, while α-amylase-enhancing activity in a concentration-dependent manner was noted.

The results of this study demonstrated snake venom PLA2 neutralization, which is a major toxic enzyme present in snake venom, along with significant antioxidant properties. This study highlights the potential of Datura seed proteins as an antiophidic along with other therapeutically important applications.