engleski

Volatiles of Lunaria annua L. obtained by conventional and microwave-assisted isolation and their cytotoxic activity

Lunaria annua L. (annual honesty) belongs to Brassicaceae family, which is highly characterized by glucosinolates (GSL). It is native to the Balkans and southwest Asia. Unmodified L. annua oil has been used on a small scale as an industrial lubricant and as a source of nervonic acid used in pharmaceutical and nutraceutical applications. The goal of the present study was the isolation of the volatiles by conventional methods which include hydrodistillation using a Clevenger type apparatus, CH2Cl2 extraction after autolysis as well as by modern technique using microwave (MW) distillation and extraction. Isothiocyanates (ITCs), the main volatiles identified by GC-MS, originated from GSL degradation, i.e. isopropyl ITC from glucoputranjivin (1), 5-(methylsulfinyl)pentyl ITC from glucoalyssin (2) and 6- (methylsulfinyl)hexyl ITC from glucohesperin (3). Two other ITCs, namely pent-4-enyl ITC and hex-5-enyl ITC were also detected indicating the presence of two more corresponding GSLs. However, LC-PDA-MS/MS analysis of desulfoGSLs confirmed the presence of only 1, 2, and 3. Thus, it can be suggested that pent-4-enyl ITC and hex-5-enyl ITC are formed due to the thermal instability of 5-(methylsulfinyl)pentyl ITC and 6-(methylsulfinyl)hexyl ITC, respectively during GC-MS analysis. Hydrodistillate, CH2Cl2 extract after autolysis as well as MW extract were evaluated for their cytotoxic activity against two tumor cell lines. The activities were observed after 4, 24, 48, and 72 h and expressed as IC50. Hydrodistillate, CH2Cl2 extract and MW extract showed the best cytotoxic activity on human lung cancer cell line A549 during incubation time of 72 h (IC50 152.8, 18.79, and 33.46 μg/mL, respectively), while the best effect on breast cancer cell line MDA-MB-231 was after 48 h (IC50 67.44, 6.0 and 11.8 μg/mL, respectively). Following the Al-Gendy, et al. criteria, who categorized the activities against the tested cell lines based on IC50 values, CH2Cl2 extract and MW extract may be considered as highly active, while hydrodistillate as moderately active.

Lunaria annua ; isothiocyanates ; glucosinolates ; microwave-assisted isolation ; cytotoxic activity

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