A comprehensive review of the phytochemistry and agricultural potential of Combretum erythrophyllum (Burch.) Sond. in crop protection

Combretum erythrophyllum (Burch.) Sond, commonly known as river bushwillow, is an indigenous southern African tree traditionally used in human and animal medicine, and now gaining attention for its potential in sustainable crop protection. Despite its widespread use, there is limited information of its application in agriculture. The aim of the present review is to summarise the phytochemical composition, antimicrobial, and insecticidal properties of C. erythrophyllum, focusing on its role as a botanical pesticide. Data on C. erythrophyllum was gathered using the following databases: Google Scholar, Scopus, Web of Science, ScienceDirect, PubMed, and SpringerLink. This review considered peer-reviewed research articles published between 1997 and 2024 in English. Eligible studies included investigations reporting on the use of C. erythrophyllum in crop protection, including activity against agricultural pests, phytopathogenic microbes as well as studies describing phytochemical compounds associated with plant protection mechanisms. Studies focusing exclusively on pharmacological or human/animal medicinal applications without relevance to agricultural or plant protection were not considered within the scope of this review. Findings revealed that C. erythrophyllum leaf extracts, obtained using different solvents exhibited in vitro antifungal activity against fungi, such as Fusarium spp and Aspergillus spp with activity ranging from 0.08 to 1.25 mg/mL. A total of 45 compounds has been identified in the leaf and bark through various analytical methods, with GC–MS profiled 27 compounds. Identified compounds belonged to different class, including flavonoids, triterpenoids, polyphenols and phenolic acids. Compounds such as apigenin, quercetin, kaempferol and 5‑hydroxy-7,4′-dimethoxyflavone have been reported to have antifungal, antibacterial, nematicidal, insecticidal, and activities highlighting the plant’s potential as a natural biocontrol agent for sustainable agriculture. Although its potential as an eco-friendly alternative to chemical pesticides, further studies are required to validate its efficacy under field conditions and support its development as an effective biocontrol agent.