Profiling of Bioactive Compounds and Bioactivity of the Kenaf (Hibiscus Cannabinus L.) Leaf Extract

The current research examines the impact of different solvents and maturity stages of the kenaf leaf (Hibiscus Cannabinus L. var. Everglade 51) on the bioactive compound and bioactivity, which specifically focused on antioxidant and antimicrobial properties. The kenaf's leaf powder was extracted sequentially using hexane, acetone, and methanol. The total phenolic compound (TPC), flavonoid content (TFC), and free-radical scavenging activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay were measured using UV–Vis spectrometry. The antibacterial activity of the extract was determined using the disc diffusion method on both Gram-positive and -negative bacteria. Results show that the methanol extracts had a significant (p < 0.05) quantity of TPC and TFC compared to other extracts. Results showed that the antioxidant compound amount measured as TPC and TFC in extract increased from shoot stages into mature leaves by 11% and 24%, respectively. As expected, methanolic extract of mature leaf exerts the highest TPC and TFC value compared to that of other solvents. This also reflects the antioxidant activity among the different extract where methanolic extract showed the highest antioxidant activity with value 60.48 ± 0.24% of radical scavenging activity. Meanwhile, only the methanolic and acetone extracts demonstrated a significant (p < 0.05) inhibitory zone against Gram-negative microorganisms. Overall, mature kenaf leaf extracted with methanol and acetone solvents showed a particularly high in terms of antioxidant capacity and antimicrobial characteristics. Mature kenaf leaf was recommended for food product development due to their strong antioxidant activity and ability to inhibit Gram-negative bacteria.