Antioxidant and Antibacterial Activity of Endophytic Fungi Isolated from The Leaves of Sungkai (Peronema canescens)

Abstract

Sungkai (Peronema canescens) is a medicinal plant widely used in Indonesia. Its leaves are believed to have the potential to treat fever and boost the immune system. This study investigated the antioxidant and antibacterial activity of endophytic fungi extracts obtained from Sungkai leaves. This will provide basic information for developing the potential of natural ingredients as antioxidants and antibacterials. Endophytic fungi residing in Sungkai leaves were identified morphologically. The antioxidant test was completed using DPPH, while the antibacterial activity was tested using the paper disk diffusion method. Most potential endophytic fungal isolates were identified through molecular identification, and the isolation of a bioactive compound was achieved using column chromatography. The structure of the compound was determined using 1D and 2D NMR spectroscopy methods. Four endophytic fungi isolates were observed in the Sungkai leaves (code RND1–RND4). RND3 demonstrated very strong antioxidant activity (IC50 < 20 µg/mL) and strong antibacterial activity. Based on the molecular test, RND3 was identified as Aspergillus niger. The pure compound isolated from RND3 revealed weak and strong antioxidant (IC50 > 500 µg/mL) and antibacterial (MIC ≤ 64 µg/mL) properties, respectively. Spectroscopic analysis showed that compound 1 was 3-benzyl-2,6-dihydroxy-1,4,11,13-tetramethyl-5- methylene-12,15-dioxo-14-oxabicycloheptadeca-8,16-diene-7-carboxylic acid. Through further research, this study can be used as a basis for the development of compounds as raw materials for drugs.