Assessment of Antioxidant and Antimicrobial Activities, along with the Quantification of Diverse Phytoconstituents Using GC-MS and HPTLC Of the methanolic extract of Raphanus sativus leaves

Abstract

This study delves into the phytochemical composition and pharmacological potential of the methanolic extract derived from the leaves of Raphanus sativus. Preliminary phytochemical analysis revealed the presence of glycosides, flavonoids, cardiac glycosides, tri-terpinoids, and phytosterols. Thin Layer Chromatography (TLC) demonstrated the existence of Kamferol, Apigenin, Chlorogenic Acid, and Caffeic Acid in the extract. High-Performance Thin-Layer Chromatography (HPTLC) further quantified Kamferol (0.59 mcg/ml), Caffeic Acid (0.16 mcg/ml), and Chlorogenic Acid (2.29 mcg/ml). The amino acid profiling has shown the good food value of the extract and that has resulted with L-Glutamic acid (0.08 μg/ml) , L-Histidine (0.053 μg/ml) and L-tyrosine (0.079 μg/ml). Gas Chromatography-Mass Spectroscopy (GC-MS) analysis identified 25 compounds, with 5-Hydroxymethylfurfural and 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy exhibiting radical scavenging and anti-proliferative activities. Additionally, 7,10,13-Hexadecatrienoic acid, (Z,Z,Z), displayed anti-bacterial, anti-oxidant, immune-stimulant, and anti-tumor activities. Notably, n-Hexadecanoic acid, a major constituent (Area% - 12%), possesses anti-inflammatory properties.

Quantitative analysis indicated a total phenolic content of 55.57±0.37 mg/100g and flavonoid content (quercetin) of 115.73±0.21 mg/100g. The extract exhibited significant DPPH radical scavenging activity (IC₅₀ = 20.0±0.1 µg/ml) compared to ascorbic acid (IC50 = 43.5 ±0.35 µg/ml). Evaluation of antimicrobial activity has shown against the gram-negative bacteria E. coli & S. typhi with zone of inhibition 8.5 mm and 7.2±0.1 mm respectively & compared with gram-positive S. aureus and Bacillus subtilis with zone of inhibition   6.8±0.1 mm and 7.1 mm at the lowest concentration of 50 mg/mL, supported by GC-MS analysis identifying potential antimicrobial compounds.

The presence of n-Hexadecanoic acid suggests potential anti-inflammatory effects, offering promise in mitigating disorders like diabetes. In-silico and in-vivo studies are recommended to further explore these effects. The study establishes R. sativus leaves as a rich source of diverse phyto-constituents with multi-directional health benefits, supporting its potential as a valuable nutritional supplement.