Microwave-Assisted versus Conventional Isolation of Glucosinolate Degradation Products from Lunaria annua L. and Their Cytotoxic Activity

Biomolecules. 2020 Feb 1;10(2):215. doi: 10.3390/biom10020215.

Abstract

Glucosinolates (GSLs) from Lunaria annua L. seeds were analyzed qualitatively and quantitatively by their desulfo counterparts using UHPLC-DAD-MS/MS technique and by their volatile breakdown products, isothiocyanates (ITCs), using GC-MS technique. GSL breakdown products were obtained by conventional techniques (hydrodistillation in a Clevenger type apparatus (HD), CH2Cl2 extraction after myrosinase hydrolysis (EXT) for 24 h) as well as by modern techniques, microwave-assisted distillation (MAD) and microwave hydrodiffusion and gravity (MHG). Seven GSLs were identified as follows: isopropyl GSL (1), sec-butyl GSL (2), 5-(methylsulfinyl)pentyl GSL (3), 6-(methylsulfinyl)hexyl GSL (4), 5-(methylsulfanyl)pentyl GSL (5), 6-(methylsulfanyl)hexyl GSL (6), and benzyl GSL (7). Additionally, pent-4-enyl- and hex-5-enyl ITCs were detected in the volatile extracts. However, their corresponding GSLs were not detected using UHPLC-DAD-MS/MS. Thus, they are suggested to be formed during GC-MS analysis via thermolysis of 5-(methylsulfinyl)pentyl- and 6-(methylsulfinyl)hexyl ITCs, respectively. Volatile isolates were tested for their cytotoxic activity using MTT assay. EXT and MHG showed the best cytotoxic activity against human lung cancer cell line A549 during an incubation time of 72 h (IC50 18.8, and 33.5 μg/mL, respectively), and against breast cancer cell line MDA-MB-231 after 48 h (IC50 6.0 and 11.8 μg/mL, respectively). These activities can be attributed to the ITCs originating from 3 and 4.

Keywords: Lunaria annua; breast cancer cell line MDA-MB-231; cytotoxic activity; glucosinolates; human lung cancer cell line A549; isothiocyanates; microwave-assisted isolation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Cell Line, Tumor
  • Cell Survival
  • Diffusion
  • Gas Chromatography-Mass Spectrometry
  • Glucosinolates / analysis*
  • Glucosinolates / isolation & purification*
  • Glycoside Hydrolases / metabolism
  • Humans
  • Hydrolysis
  • Inhibitory Concentration 50
  • Isothiocyanates / chemistry*
  • Lamiales / chemistry*
  • Microwaves*
  • Plant Extracts / analysis
  • Seeds / metabolism
  • Tandem Mass Spectrometry
  • Time Factors

Substances

  • Glucosinolates
  • Isothiocyanates
  • Plant Extracts
  • Glycoside Hydrolases
  • thioglucosidase