GC-MS, FTIR, XRD, UV–Vis, and HPLC profiling of the natural bioactive constituents of Lemna minor L. extract and its in-vitro antimicrobial and anti-parasitic activities against pathogenic organisms

The current study focuses on Lemna minor L. (common duckweed) through proximate analysis, qualitative and quantitative phytochemical analysis by UV spectroscopy (UV), gas chromatography and mass spectroscopy (GC-MS), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction analysis (XRD). The phytochemical investigation of the fresh sample of L. minor was compared with the powdered sample extracted using different drying procedures. The highest moisture content was recorded in fresh samples (87.94 %), while maximum percentages of ash, fiber, and protein were found in oven-dried powder as 14.81 %, 24.01 %, and 34.92 %, respectively. The freeze-dried powder contained the greatest percentages of fat (8.48%) and carbohydrates (17.5%). The qualitative phytochemical analysis detected variable concentrations of bioactive compounds. Quantitative analysis revealed that tannins were found in the maximum concentration across all solvents, while non-polar or polar steroids were extracted the least. In terms of mineral content, the freeze-dried plant samples contained the maximum levels of potassium (54.51 mg/100g), followed by phosphorus (31.750.25 mg/100g), magnesium (18.25±0.25 mg/100g) and sodium (4.4±1 mg/100g). The maximum antibacterial potential was achieved against E. coli, that was 21.4 mm zone of inhibition (ZOI). Similarly, the maximum fungal inhibition was observed against A. niger, which was 21 mm ZOI at the highest concentration of 75 μl. The parasite's promastigote and amastigote forms each had a significant death rate of 75.40±1.16 and 60.15±0.12 at 150 g/mL, respectively. Schematic diagram of the whole study • Proximate and mineral analyses performed for fresh and dried L. minor. • Oven-dried L. minor shows the highest protein (34.9%) and fiber (24.0%). • Freeze-dried L. minor contains the highest fat (8.5%) and carbohydrates (17.5%). • Strong antibacterial activity of L. minor (21.4 mm ZOI) against E. coli. • L. minor shows significant antileishmanial activity (75.4% promastigote kill).