17 - Lippia javanica

Abstract

The highly aromatic Lippia javanica (Burm.f.) Spreng (Verbenaceae) is a multipurpose medicinal shrub with leaves that have a characteristic lemon-scent when bruised. ‘Fever-bush’ as it is commonly known, has widespread ethnobotanical applications, including the treatment of fevers, respiratory and gastrointestinal complaints, skin infections and insect repellence. The plant is naturally distributed throughout South Africa and various other southern African countries. Lippia javanica is one of the few commercialised medicinal plants with products that include herbal teas (Mosukudu tea), and the essential oil is used in perfumery and candles. The biological properties of the plant have been extensively studied in vitro, while the volatile and non-volatile fractions of the plant have been well characterised. The chromatographic profiling of the volatile and non-volatile fractions of L. javanica is reported and the quality control parameters and markers documented, herein. Representative L. javanica plants from various areas were collected, and the aerial parts were divided into two. The essential oil was obtained by hydrodistillation of one part, while the non-volatile fraction was obtained through methanol extraction. The essential oil was analysed by high-performance thin-layer chromatography (HPTLC) and gas chromatography coupled to mass spectrometry (GC-MS), while the non-volatile fraction was analysed using ultra-performance liquid chromatography, coupled to mass spectrometry and photodiode array detection (UPLC-MS-PDA), and HPTLC. The HPTLC essential oil profiles viewed under white light revealed chemical variation between the samples. Four different chemotypes could be identified, based on the prominent bands in each oil. The chemotypic variation was confirmed by GC-MS, which was used to identify myrcenone-rich, linalool-rich, ipsenone-rich and piperitenone-rich chemotypes. Conversely, the non-volatile fractions showed consistency in the marker compounds, revealing verbascoside and isoverbascoside in all the samples with HPTLC. This was consistent with the UPLC-MS results, where the same marker compounds were identified.