ANTIOXIDANT ACTIVITY OF ENDOPHYTIC BACTERIAL METABOLITE COMPOUNDS FROM THE STEM BARK OF MORINGA (MORINGA OLEIFERA)

Abstract

Endophytic bacteria on the bark of the Moringa plant are microorganisms that live inside the plant and produce bioactive compounds similar to those of their host. The high antioxidant content of endophytic bacteria in Moringa plants can be beneficial for health. To determine the antioxidant activity of bacterial isolates from the bark of the Moringa plant and to identify these isolates morphologically. This study used a true experimental design. Sterilization was performed to ensure the bacteria tested were endophytic. Microscopic identification was performed using Gram staining and screening using the catalase test. The best screened isolates were fermented in Nutrient Broth and extracted with Ultrasound Assisted Extraction (UAE). The extract results were tested for antioxidant activity using the DPPH method to obtain an IC₅₀ value to categorize its strength. Four streak isolates of endophytic bacteria that taken from the bark of the Moringa plant were found, with similar colony patterns observed in NA growth media. Microscopic identification revealed that the bacteria were Gram-positive, with a single bacillus, and the catalase screening results were positive. The metabolite extracts tested using the DPPH method yielded relatively high IC₅₀ values in all three replicates. This indicates a very weak antioxidant status. The endophytic bacterial isolates from the bark of the Moringa plant in this study can be suspected to belong to the genus Bacillus Based on identification, the antioxidant activity of the metabolite compounds of endophytic bacterial isolates is classified as weak.