Phytochemical and Biological Activities of Pseudocalymma elegans: A False Garlic

Evaluation of phytochemical constituents and antioxidant and antimicrobial activities of hexane (PELH), dichloromethane (PELDCM), ethyl acetate (PELEA), and MeOH (PELM) extracts of young leaves of Pseudocalymma elegans have been carried out. Moreover, extracts have also been explored for the presence of sulphur containing compounds, 1,2-dithiolane (33), diallyl disulfide (35), 3-vinyl-1,2-dithiacyclohex-5-ene (37), and diallyl trisulfide (38) responsible for the garlic like smell of P. elegans. All the extracts were found to be antioxidant and showed potent inhibition with IC₅₀ values of 0.168 ± 0.001, 0.128 ± 0.002, 0.221 ± 0.011, and 0.054 ± 0.001, respectively, as compared to standard drugs ascorbic acid (AA) and butylated hydroxytoluene (BHT). The ethyl acetate extract (PELE) showed excellent activities against few Gram-positive and Gram-negative bacteria and some fungi as compared with standard drug ceftriaxone (3rd generation cephalosporin) and nystatin, respectively. Chemical constituents of hexane, dichloromethane, and ethyl acetate extracts were identified by gas chromatography-mass spectrometry and mass spectral library search. Over all 55 chemical constituents were first time identified from the leaves which included branched and n-hydrocarbons, fatty acids, fatty acid methyl esters, fatty alcohols, terpenes, alkaloid, vitamins, glycosides, aromatic compounds, and sulfur containing compounds. Two known chemical constituents, ursolic acid (1) and β-amyrin (2), were also purified for the first time from the MeOH extract. To elucidate the structures of these compounds, UV, IR, EI-MS, ¹ H- and ¹³ C-NMR spectroscopy were used.