Background: Agathosma betulina (P.J. Bergius) Philans and Agathosma crenulata (L.) Pillans are species known as Buchu in Khoi, ‘boegoe’ or ‘bergboegoe’ in Afrikaans and ‘ibuchu’ in isiXhosa. Traditionally, buchu has served as an antipyretic, antispasmodic, diuretic, treatment for constipation, and unrinary tract infections. Aim: The aim of this review is to contribute to the better understanding of the cultivation practices and phytochemical constituents of buchu. Setting: This review provides an overview of cultivation practices and phytochemical composition of A. betulina and A. crenulata. Method: A comprehensive search was conducted on existing literature on the traditional uses, medicinal use, cultivation, and phytochemistry of A. betulina and A. crenulata in online databases. Results: Buchu is highly valued for its oil, and used globally in culinary and cosmetic industries for its flavour and aroma. Rising demand for its essential oils and therapeutic products in the early 2000s led to overharvesting, threatening natural populations. To address this, cultivation was encouraged, but limited knowledge of its cultivation methods raises concerns about the impact of further commercial expansion on the species and its ecosystem. Buchu contains bioactive compounds such as diosphenol, menthone, and pulegone, which have demonstrated antibacterial, anti-inflammatory, and antioxidant properties in preclinical studies. Conclusion: Further research should focus on cultivation practices, non-volatile constituents, in vitro, in vivo, and clinical research of the species health benefits. Contribution: Bioprospecting for new health-promoting items needed in the primary healthcare delivery system can benefit from this study’s addition to the body of knowledge already available on the two commercially available buchu plants.

The role of medicinal plants in primary healthcare and livelihoods around the world is both ancient and well-documented. Agathosma betulina (P.J. Bergius) Pillans, commonly known as ‘buchu’, has long been utilised in traditional medicine as a household remedy for various ailments and is also valued for its essential oils in the cosmetics and pharmaceutical industries. This study aimed to profile and quantify the secondary metabolites in buchu using ultra-performance liquid chromatography quadrupole time-of-flight combined with mass spectrometry (UPLC-QTOF-MS) techniques, whereby plant material from three distinct locations in the Western Cape Province, Groot Winterhoek, Citrusdal, and Cederberg, was collected. A total of 32 maker compounds were identified from buchu leaves. The results revealed a significant location-dependent variation in the accumulation of multiple classes of phytochemicals, including phenolic acids, flavonoids, saponins, terpenoids, oligosaccharides, vitamins, and steroids. Citrusdal samples had the most bioactive compounds compared to the Cederberg and Groot Winterhoek. Citrusdal had the highest flavonoid levels, while Cederberg samples were the richest in phenolic acids and Groot Winterhoek was dominant in iridoid glycoside levels. Principal component analysis (PCA) revealed distinct clusters corresponding to the three different regions, confirming chemical differences. Elucidating the distribution of secondary metabolites in this species may provide new information for possible medicinal and pharmacological uses, such as the creation of novel and enhanced organic medications and food products. These results will aid in selecting a buchu chemotype with optimal attributes for the intended therapeutic application, helping to protect wild populations from over-exploitation through cultivation.

Lobostemon fruticosus (L.) H. Buek is an indigenous South African medicinal plant valued for its traditional therapeutic uses; however, information on its phytochemical variation and pyrrolizidine alkaloid (PA) content across geographical populations remains limited. This study investigated the secondary metabolite composition and PA accumulation in nine biological samples (three geographical locations × three biological replicates) of L. fruticosus collected from Rhodes Memorial, Doringrivier, and Grootnek Fontein in the Western Cape Province between January and March 2025 using untargeted UPLC-QTOF-MS and targeted LC-MS/MS, with values presented as mean ± standard deviation (SD). A total of 15 secondary metabolites of different classes were putatively annotated. Seven compounds, including kaempferol, jaceidin 7-rhamnoside, schizotenuin F, senburiside III, cosmosporaside B, lirioresinol A, and (−)-steganacin, are reported for the first time in L. fruticosus. Significant geographical variation (p < 0.05) was observed, with Doringrivier containing the highest relative abundances of rutin (4815.60 ± 18.96 mg CE g⁻¹ DW), rosmarinic acid (3846.89 ± 285.78 mg CE g⁻¹ DW), and rabdosiin (5142.10 ± 651.00 mg CE g⁻¹ DW). Six of the ten targeted PAs were detected, with lycopsamine N-oxide being the predominant alkaloid (3.89 mg kg⁻¹ in Grootnek Fontein). Principal component analysis explained 97.2% of the total metabolomic variation (PC1 = 72.6%; PC2 = 24.6%) and clearly separated the three geographical populations. The OPLS-DA model showed strong discrimination among populations (R²X = 0.725, R²Y = 0.998, and Q² = 0.994), supporting the presence of location-specific chemotypic differences. The observed chemotypic differences may be associated with variation in soil properties, climatic conditions, water availability, altitude, and nutrient status among the study sites. Collectively, the results provide a foundation for chemotype selection, quality control, conservation, and the safe medicinal utilization of this species.

Agathosma betulina (P.J. Bergius) Pillans is an aromatic medicinal shrub endemic to South Africa’s Cape Floristic Region, widely used in traditional medicine to treat urinary tract infections, gastrointestinal disorders, colds, and wounds. Despite its commercial importance, limited information is available on how different growing environments influence its phytochemical composition. This study profiled the secondary metabolite composition of A. betulina leaves collected from wild, open-field cultivation, and glasshouse-grown environments using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) combined with chemometric analyses. Methanolic extracts prepared from nine samples were analysed, resulting in the confident annotation of 21 secondary metabolites (MSI Level 2), comprising phenolic acids, flavanones, flavones, and flavonol glycosides. Rutin was the predominant flavonoid, with concentrations of 194.62, 185.71, and 58.82 mg CE kg⁻¹ DW in wild, cultivated, and glasshouse-grown plants, respectively. Neochlorogenic acid accumulated predominantly in cultivated plants (51.84 mg CE kg⁻¹ DW) compared with wild plants (3.31 mg CE kg⁻¹ DW), while coumaroylquinic acid (125.93 mg CE kg⁻¹ DW) and feruloylquinic acid (30.74 mg CE kg⁻¹ DW) were most abundant under glasshouse conditions. Tricin-7-O-glucoside (62.93 mg CE kg⁻¹ DW) and isorhamnetin-3-O-glucoside (31.26 mg CE kg⁻¹ DW) also accumulated significantly in cultivated plants. Partial Least Squares Discriminant Analysis (PLS-DA) score explained 92.1% of the total variation (C1 = 63.8%; C2 = 28.3%), together with hierarchical heat map clustering and VIP, clearly separating samples according to growing environment. Wild plants exhibited the greatest metabolite diversity, cultivated plants showed intermediate metabolite profiles, and glasshouse-grown plants displayed reduced flavonoid accumulation and overall chemical diversity. These findings demonstrate that growing environment strongly influences secondary metabolite accumulation in A. betulina and provide valuable information for optimizing cultivation practices, quality control, and conservation strategies for this economically important medicinal species.