Lotus (Nelumbo nucifera L.) rhizomes are applicable in traditional medicine due to their therapeutic properties, which include compounds such as phenolics, tannins, alkaloids, and flavonoids. This study aimed to analyze the phytochemical properties, total flavonoid content, antioxidant activity, and bioactive compounds using gas chromatography-mass spectrometry (GC-MS) of N. nucifera rhizomes obtained from the Joto Reservoir in East Java, Indonesia. The results showed lotus rhizomes contain secondary metabolites, such as phenols, flavonoids, tannins, alkaloids, steroids, and terpenoids, with a total flavonoid content of 9.23 ± 0.04 mg/g QE. The DPPH (2,2-diphenyl-1-picrylhydrazyl) test indicated that the extract had a moderate antioxidant activity, with an IC₅₀ of 57.88 ppm. The GC-MS profiling confirmed 238 identified compounds in the crude ethanolic rhizome extract of N. nucifera. The bioactive compounds included linoleic acid (5.90%), hexadecanoic acid (3.61%), octadecadienoic acid (2.62%), stigmasterol 3.β (2.13%), Z-7-hexadecenal (1.73%), 24-norursa-3,12-diene (1.53%), lanosterol (1.51%), campesterol (1.28%), beta-sitosterol (1.14%), betulin (0.82%), and rolipram (0.60%). Further studies revealed the ethanol extract of N. nucifera rhizomes is a valuable source of many bioactive compounds, supporting its beneficial traditional medicinal uses for health.

Keywords: Lotus (N. nucifera L.), antioxidant activity, GC-MS profiling, Joto reservoir, phytochemicals

Key findings: Phytochemical analysis showed the presence of flavonoid, alkaloid, and phenolic contents, which can enhance the efficacy of herbal medicines. The GC-MS profiling of lotus (N. nucifera) rhizome extract identified bioactive compounds, such as linoleic acid, stigmasterol, betulin, and rolipram.