Solanum melongena (Eggplant) Crude Anthocyanin Extract and Delphinidin-3- glucoside protects Caenorhabditis elegans against Staphylococcus aureus and Klebsiella pneumoniae

Abstract

Background and Objective: During infection, ROS signaling is activated to protect the cells from invading microorganisms. However, high level of ROS may also damage the host tissue. The anthocyanin delphinidin is known to have a strong antioxidant activity which protects cells from oxidative damage. We explored the potential of crude anthocyanin extract from the fruit of Solanum melongena (Eggplant) and Delphinidin-3- glucoside in enhancing the innate immunity in Caenorhabditis elegans against Staphylococcus aureus and Klebsiella pneumoniae.

Methodology: We used Caenorhabditis elegans to study innate immune response because it lacks adaptive immunity. First, we determined the sublethal concentration of S. melongena crude anthocyanin extract (SMCAE) and Delphinidin-3-glucoside (D3G) in C. elegans. We used the sublethal concentration of SMCAE and D3G to supplement the nematodes during its exposure to S. aureus and K. pneumoniae. We then observed its survival rate until day five post-L4. We also tested SMCAE and D3G for probable antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae.

Results and Conclusion: We found out that both SMCAE and D3G showed no inhibitory effect on the growth of the bacteria. However, both SMCAE and D3G enhanced the survival of the nematode when exposed to S.aureus and K. pneumoniae. Overall, we speculate that the anthocyanin delphinidin in S. melongena crude extract protected the C. elegans against S. aureus and K. pneumoniae infection through its antioxidant activity.