Gas chromatography–mass spectrometry (GC–MS) analysis and high-performance thin-layer chromatography (HPTLC) fingerprinting profile of petroleum ether extract of Laurus nobilis Linn. (Yue Gui Ye) leaves

Abstract

Background

Laurus nobilis Linn. (Lauraceae), commonly known as Bay Laurel and referred to as Yue Gui Ye in Traditional Chinese Medicine (TCM), has been used for centuries as a culinary spice and a therapeutic herb. It is reputed for its carminative, antiseptic, and anti-inflammatory actions and for promoting digestion and circulation of Qi. Despite widespread usage, the systematic chemical profiling of its non-polar (petroleum ether) extracts remains limited, which constrains standardization efforts and pharmacological validation. Previous studies have largely focused on essential oils obtained by steam distillation, leaving a knowledge gap regarding semi-volatile components uniquely extractable in petroleum ether.

Objective

To establish chromatographic fingerprints and to identify major volatile and semi-volatile compounds in the petroleum ether extract of L. nobilis leaves, thereby supporting its quality control and ethnopharmacological relevance. Additionally, to compare the detected compounds with previous literature to identify newly reported and previously confirmed phytoconstituents.

Methods

Fresh L. nobilis leaves were collected, authenticated, and extracted using petroleum ether (40–60°C) via Soxhlet apparatus. The extract was analyzed by HPTLC using silica gel 60 F₂₅₄ plates and scanned at 366 nm, and by GC–MS using a Shimadzu TQ-8050 HS20 system. Compounds were identified using NIST 2020 library data. Literature between 2010–2024 was systematically reviewed using PubMed, Scopus, and Google Scholar to determine the novelty or previously reported nature of each compound.

Results

The HPTLC fingerprint displayed eight major peaks, confirming chemical diversity. GC–MS analysis identified twenty-nine volatile compounds dominated by α-pinene (32.38%), o-cymene (20.06%), γ-terpinene (9.83%), and β-myrcene (7.94%). Comparison with earlier studies revealed that key monoterpenes including α-pinene, β-myrcene, limonene, linalool, and γ-terpinene have been consistently reported in essential oils and organic extracts. However, six detected semi-volatile compounds (tetradecane, hexadecane, pentadecene isomer, benzaldehyde derivative, phytol acetate, and a minor sesquiterpene oxide) appear newly reported for petroleum ether extracts, indicating chemotype broadening beyond essential-oil profiles. Replicate analysis showed less than 2% RSD, confirming analytical consistency.

Conclusion

A chemical fingerprint of Yue Gui Ye was established using GC–MS and HPTLC. The findings confirm the predominance of α-pinene and o-cymene reported extensively in earlier literature, while also highlighting several newly detected constituents unique to petroleum ether extraction. This comparative profiling enhances the understanding of L. nobilis phytochemical diversity and provides reference data for herbal standardization in Traditional Chinese Medicine and phytopharmaceutical research.