Phytochemical profile of stem extract of Carthamus oxycantha and identification of herbicidal and antimicrobial constituents

The present study was carried out to enlist herbicidal and antimicrobial compounds in the methanolic stem extract of Carthamus oxycantha, a problematic weed of Asteraceae. Methanolic stem extract was subjected to GC-MS analysis that revealed the presence of 150 constituents in the extract. The most abundant compound was Niacin (45.375%) followed by D-ribofuranose, 5-deoxy-5-(methylsulfinyl)-1,2,3-tris-O-(trimethylsilyl)- (14.528%); 9,12-octadecadienoic acid (Z,Z)-, methyl ester (4.951%); γ-tocopherol (4.638%); hexacosane (4.148%); 3-phenyllactic acid, 2TMS derivative (2.675%); 13-retinoic acid, (Z)-, TMS derivative (2.461%); 2,2,5,5-tetramethyl-4-ethyl-3-imidazoline-1-oxyl (2.276%); octadecanoic acid (1.851%); 2-deoxy-1,3,4,5-tetrakis-O-(trimethylsilyl); pentitol (1.757%); 3,5,5-trimethyl-4-(3-((trimethylsilyl)oxy)butyl)cyclohex-2-enone (1.505%); methyl 9.cis.,11.trans.t,13.trans.-octadecatrienoate (1.136%); and benzoic acid, 3-[(trimethylsilyl)oxy]-, trimethylsilyl ester (1.044%). Peak areas for the rest of the compounds were below 1%. Among the identified compounds, 9,12-octadecadienoic acid (Z,Z)-, methyl ester (3), hexacosane (5), 9,12-octadecadienoic acid (Z,Z)- (28), tetradecanoic acid, methyl ester (29), hexadecanoic acid, methyl ester (30), γ-sitosterol (33), 9,12,15-octadecatrienoic acid, (Z,Z,Z)- (48), dodecanoic acid (68) and eicosane (128) are known to possess antimicrobial activities. Compound 28 is also known for its herbicidal activity as a binary mixture with xanthoxyline. This study concludes that the stem extract of C. oxycantha primarily comprises antifungal and antibacterial compounds.