Layer chromatography-bioassays directed screening and identification of antibacterial compounds from Scotch thistle

Abstract

Highlights:-First direct transfer of OPLC mobile phase to flash chromatography -Antibacterial profiling of Scotch thistle (Onopordum acanthium L.) leaf extract -TLC/OPLC-DB using plant and human pathogen bacteria and a probiotic, human gut bacterium L. plantarum utilized for investigation of the extract against eight bacterial strains including two plant and three human pathogens and a soil, a marine and a probiotic human gut bacteria. Antibacterial fractions obtaining infusion-transfusion OPLC were transferred to HPLC-MS/MS analysis that resulted in the characterization of three active compounds and two of them were identified as, linoleic and linolenic acid. OPLC method was adopted to preparative-scale flash chromatography for the isolation of the third active compound, which was identified after a further semi-preparative HPLC purification as the germacranolide sesquiterpene lactone onopordopicrin. Pure onopordopicrin exhibited antibacterial activity that was specified as minimal inhibitory concentration in the liquid phase as well.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

“…Onopordopicrin ( 122 ), a germacranolide sesquiterpenoid lactone, was isolated from Onopordum acanthium L. (Asteraceae) and exhibited moderate activity against B. subtilis , Lactobacillus plantarum , Vibrio fischeri , and Xanthomonas euvesicatoria …”

Traditional Medicine Plant, Onopordum acanthium L. (Asteraceae): Chemical Composition and Pharmacological Research

“…A total of 3.5 g of onopordopicrin was obtained from 10 kg of fresh leaves using water extract and purification with chloroform. Later, onopordopicrin was isolated from leaves [35]. Arctiopicrin was also found in O. acanthium herb (Figure 6) [27].…”

“…In comparison with this, the work of Tonguç [50] described a smaller amount of fatty acids (212 g/kg vs. 144 g/kg). Additionally, linoleic and linolenic acids were detected in the leaves of O. acanthium [35].…”

“…All of the bacterial cultures were sensitive to component hR f 37; however P. maculicola was inhibited by a high amount of this compound. Onopordopicrin inhibited all of the bacterial cultures; however P. maculicola was resistant to 20 μg onopordopicrin [35].…”

Onopordopicrin from the new genus Shangwua as a novel thioredoxin reductase inhibitor to induce oxidative stress-mediated tumor cell apoptosis

“…Compounds 1-3 (Figure 1(B)) bearing the same lactone ring are onopordopicrin (Compound 1, ONP), 11b,13-dihydro-19-desoxycnicin (Compound 2, C2), and 8-oxo-15-hydroxygermacra-1(10)E, 4Z-dien-11bH-12, 6a-olide (Compound 3, C3), respectively. ONP was previously reported to harbor antibacterial and antifungal 4,5 , antiplasmodial 6 , phytotoxic 7 , anti-ulcerogenic 8 , and anti-inflammatory activities 9 , while the biological activities of C2 and C3 are rarely reported. However, despite ONP exhibits cytotoxicity, whether ONP is effective for inhibiting tumor growth and acting mechanism remains unclear.…”