Characterization and isolation of quinones from Tectona grandis Linn. leaves using innovative hyphenation of TLC-MS interface with LC/MS/MS system

Importance of the Topic

The characterization of quinones from Tectona grandis leaves addresses the need for efficient identification of color pigments and bioactive compounds in natural products. This work enables rapid screening of phytochemicals and supports applications in quality control, pharmaceuticals and industrial analytics.

Objectives and Overview of the Study

The study aims to isolate and identify quinone constituents in teak leaf extracts by combining high performance thin layer chromatography with mass spectrometry through an innovative hyphenated TLC-MS interface. Key goals include rapid online transfer of compounds from TLC plates to an LC/MS/MS system and structural confirmation via m/z and fragmentation profiling.

Methodology and Instrumentation

• Sample Collection and Preparation
  Teak leaves were harvested, shade-dried, powdered and extracted with acidified ethyl acetate under sonication.
• HPTLC Separation
  Silica gel F254 plates were developed in two steps using mixtures of petroleum ether, ethyl acetate and formic acid. Six distinct colored bands were visualized under CAMAG densitometry.
• TLC-MS Interface
  A CAMAG hyphenation unit enabled semi-automatic extraction of target zones by applying solvent under controlled piston pressure and direct infusion into the mass spectrometer.
• LC/MS/MS Conditions
  Shimadzu Nexera UHPLC coupled to an LCMS-8040 triple quadrupole operated in dual ion source mode. Mobile phase comprised 0.1 percent formic acid in water and acetonitrile (30 70 v/v), flow rate 0.3 mL/min, oven at 40 °C. Full scan Q3 mode in positive and negative polarities followed by automated collision energy optimization.

Key Results and Discussion

HPTLC resolved six bands with Rf values ranging from 0.06 to 0.67. Band 3 (Rf 0.26) produced a [M+H]+ ion at m/z 227.1 and characteristic fragments at m/z 186, 163, 159, 136 and 57 under collision energy of 45 V. This pattern matched deoxylapachol, a naphthoquinone, by comparing fragmentation with an authentic standard. Similar workflows enabled the identification of other quinones such as emodin and tectoquinone.

Benefits and Practical Applications

• Rapid online coupling of TLC separations with mass spectrometry for direct compound identification.
• Cost efficient screening of complex plant matrices without extensive sample cleanup.
• Enhanced reliability of phytochemical profiling in natural product research and quality assurance.

Future Trends and Potential Applications

Continued integration of planar chromatography and high-resolution MS is expected to expand applications in metabolomics, drug discovery and environmental monitoring. Advances in automated extraction interfaces and AI-driven spectral interpretation will further streamline compound annotation from botanical sources.

Conclusion

• Innovative hyphenation of a CAMAG TLC-MS interface with Shimadzu LC/MS/MS allows efficient online extraction and mass spectrometric analysis of HPTLC bands.
• Combined Rf, m/z and fragmentation data deliver confident identification of quinones in Tectona grandis leaf extracts.
• This workflow offers a versatile platform for rapid profiling of bioactive phytochemicals in research and industrial laboratories.

References

• Naira Nayeem M Karvekar The International Journal of Pharmacology Vol 8 1 Jan 2010
• Lacret Rodney Varela Rosa Journal of Chemical Ecology Vol 37 2011 1341-1348