Innovative strategy for extraction of green cardamom via super critical fluid extractor at different levels of pressure with its application against microorganisms in vitro and in silico

The extraction of bioactive compounds from plants has emerged as a promising strategy for developing resource-efficient solutions that are both economically viable and value-driven. Supercritical fluid extraction (SFE), has become a popular technique for extraction significant plant-based compounds. Our investigation contrasted the yield, biological functions and phytochemical compositions of green cardamom extracts generated with SFE at 100, 200, and 300 bar of pressures. The maximal obtained weight was 0.279 gm upon applying 300 bar. There is a proportional elevation in the levels of most of phenolic compounds which detected using HPLC upon raising the pressure levels for extraction. Gallic acid had a significant increase (P ≤ 0.05) upon applying ascending pressure levels The extract obtained at 300 bar demonstrated the most potent antimicrobial activity against Bacillus subtilis and Candida albicans, with inhibition zones of 23.33 ± 0.58 mm and 22.17 ± 1.04 mm, respectively. Furthermore, antibiofilm and anti-hemolytic assays confirmed that higher extraction pressure enhanced the bioactivity of the extracts, with 300 bar showing the maximum effect. Time-kill kinetics demonstrated a progressive increase in microbial inhibition over time, with the 300-bar extract again displaying the most effective results. Transmission electron microscopy (TEM) revealed significant ultrastructural damage in B. subtilis and C. albicans treated with the 300-bar extract, indicating strong antimicrobial action at the cellular level. The molecular docking performance of the main constituents in green cardamom extracts gallic acid and syringic acid against B. subtilis (PDB ID: 5VX6) and S. aureus (PDB ID: 3V8J) using the molecular operating environment (MOE) software was evaluated. The docking scores (S), root mean square deviation (RMSD)_refine values, and energy terms (E_conf, E_place, E_score1, E_refine, E_score2) were analyzed to assess binding affinities. Key interactions, including hydrogen bonds, were identified, with distances and energies quantified. Syringic acid exhibited better binding (S = - 4.27 to - 5.04 kcal/mol) compared to gallic acid (S = - 4.11 to - 4.68 kcal/mol) across both targets. Interactions with residues like GLU 187 (Glutamic acid residue at position 187 in the protein sequence) and ARG 172 (Arginine residue at position 172) in 5VX6, and ASP 239 (ASP 239: Aspartic acid residue at position 239) in 3V8J, highlighted critical binding motifs. The findings concluded that green cardamom extracts, particularly those obtained at 300 bar, possess enhanced antimicrobial and antibiofilm properties, supported by both experimental and computational evidence. These results highlight the therapeutic potential of pressure-optimized SFE in maximizing the bioactivity of plant extracts.