Phytochemical and Antioxidant Analysis of Bioactive Compound Extract from Nelumbo nucifera against Cancer Proteins: In Silico Spectroscopic Approach

Nelumbo nucifera, an aquatic crop cultivated throughout Asian countries, belongs to the Nelumbonaceae family and has been widely used in traditional medicines with key pharmacological activities such as anti-viral, antipyretic, antioxidant, anti-steroid, anti-inflammatory, anti-arrhythmia, anti-obesity, and anti-aging properties. The present study aims to explore and assess the phytochemical composition, GC-MS profiling, antioxidant efficacy, and the major phytoconstituent phytol subjected to theoretical spectroscopic characterization using the DFT method. The phytochemical profiling of N. nucifera reveals the presence of alkaloids, carbohydrates, saponin, phenol, and flavonoids. The antioxidant efficacy of N. nucifera extract against DPPH and ABTS radicals increased in a concentration-dependent manner, with an IC₅₀ value of 222.84 µg and 52.67 µg, respectively. The simulated structural parameters of phytol exhibited strong concordance with experimental values. The simulated wavenumbers identified characteristic peaks corresponding to hydroxyl (OH), methylene (CH₂), and methyl (CH₃) groups. The simulated electronic spectrum of phytol exhibits a prominent absorption peak at 174 nm, predominantly attributed to the transitions H-1 → L (58%) and H → L (36%). NBO analysis reveals significant stabilization energy (7.09 kJ/mol) due to the donation of electrons from the C₂₀-H₅₈ bonding orbital to the anti-bonding orbital of C₁₈-C₁₉ via a σ → σ* transition. In Mulliken charge distribution, compared to other hydrogen, hydrogen H₆₁ in the hydroxyl (O-H) group exhibits a higher positive potential due to the influence of the oxygen atom. In addition, molecular docking was performed against breast cancer SMAD proteins to confirm its antagonist property, with binding energies of - 3.64 kcal/mol (6OM2), - 5.49 kcal/mol (1U7F), - 5.05 kcal/mol (1U7V), and - 3.73 kcal/mol (6FX4).