Essential oils from South African indigenous plants: Extraction techniques, phytochemistry, biological activities and applications

Abstract

Essential oils (EOs) are concentrated, volatile liquids derived from various plant parts, valued for their aromatic properties and widespread use in food flavoring, perfumery, and other applications. Despite substantial global advancements in EO research, limited attention has been given to EOs derived from South African indigenous plants. This review synthesizes existing literature, identifies research gaps, and highlights prospects in this field. Data were sourced from peer-reviewed articles and theses available in online repositories. The review focuses on EOs extracted from 100 South African indigenous plants, predominantly within the Asteraceae family. Hydro-distillation is identified as the primary extraction method; however, variations in EO composition and bioactivity suggest the need to explore alternative techniques. Phytochemical analyzes identified terpenes as the dominant constituents, with pinene and caryophyllene being the most prevalent monoterpene and sesquiterpene, respectively. Despite the discovery of bioactive compounds with commercial potential, significant gaps remain in biological and toxicological evaluations. EOs from these plants show promising applications in decay management and shelf-life extension of fruits and vegetables, emphasizing their value in postharvest technologies. This review highlights the economic potential of developing a sustainable indigenous EO industry in South Africa, underscoring the need for government regulation to support sustainable harvesting practices and ensure product quality. Advancing research on South African indigenous EOs is critical to unlocking their commercial and ecological benefits.