Phytochemical composition and antifungal activity of Balanites aegyptiaca seed extracts against Colletotrichum capsici causing cowpea anthracnose

Anthracnose is a major disease of cowpea caused by Colletotrichum capsici, responsible for yield losses of up to 85% in the field. Although synthetic fungicides are commonly used to control this disease and are generally effective, their use has detrimental effects on the environment and human health. Therefore, plant extracts represent a promising alternative. This study aimed to investigate the antifungal activity of phytochemical compounds present in Balanites aegyptiaca (L.) Del. seed extracts, as identified by GC-MS, against C. capsici. Phytochemical screening and GC-MS analyses were carried out, and in vitro inhibition tests were conducted using aqueous and organic (methanolic and acetonic) extracts of B. aegyptiaca seeds at concentrations of 12.5, 25 and 50 μL·mL⁻¹, compared with a control (0 μL·mL⁻¹) and a commercial fungicide containing 80% Maneb at 3.33 g·L⁻¹. The tests were performed against two isolates of C. capsici collected from the Akonolinga locality. Mycelial growth, as well as the minimal inhibitory concentrations (MIC₅₀ and MIC₉₀), were evaluated. The results showed that phytochemical screening and GC-MS analysis revealed the presence of several secondary metabolites and bioactive compounds in B. aegyptiaca seed extracts with known antifungal properties. The most abundant compounds were pyridine (52.05%) in the aqueous extract and 9-octadecenamide (29.79%) in the organic extracts. Both aqueous and organic extracts at 50 μL·mL⁻¹ inhibited up to 93% of mycelial growth in the two C. capsici isolates. The lowest MIC₅₀ values were obtained with the aqueous extract (5.81 μL·mL⁻¹ and 9.21 μL·mL⁻¹) for isolates CAK01 and CAK05, respectively. Based on these results, B. aegyptiaca seed extract appears to be a promising natural antifungal source, warranting further field trials to confirm its potential efficacy under natural conditions.