Antioxidant activity of endophytic fungi culture extracts of Christ’s thorn jujube (Ziziphus spina-christi)

This study aims to explore 50 extracts from fungal endophytes from roots, stems, and leaves of Z. spina christi based on the chemical content and their antioxidant activity. Isolation of fungal endophytes was carried out in CMMA and PDA media. Cultivation was in PDB and GYP media. Determination of antioxidant activity qualitatively by TLC-bioautography and quantitatively by DPPH method. Phytochemical screening of these extracts revealed the presence of alkaloids, phenolics, flavonoids, and tannins. The results showed that seven types of fungal endophytes had antioxidant activity, namely Trichoderma sp., Aspergillus sect. Flavi, Aspergillus sect. Nigri, Aspergillus sect. Terrei, Phomopsis sp., Sordariomycetes, and Hyphomycetes. One root isolate from PDB (Aspergillus sect. Terrei Bi. Ak. 3.3) possesses very strong antioxidant activity (IC50 of 9.17 µg/mL and AAI = 3.35) and one stem isolate (Aspergillus nigri Bi. Bt. 1.2.2) has strong antioxidant activity (IC50 22.13 µg/mL and AAI = 1.38). The fungal endophyte culture extract from GYP media produced one root isolate (Aspergillus terrei Bi. Ak. 3.3) with strong antioxidant activity (IC50 19.54 µg/mL and AAI = 1.57). It can be concluded that the fungal endophytes of Z. spina-christi have the potential to be developed as an antioxidant.