Antibacterial, Antioxidant potential, nutritional value and phytochemical content of the fruits of Dacryodes edulis (Burseraceae) and Litchi chinensis (Sapindaceae) from the Democratic Republic of Congo

Dacryodes edulis (DAED) and Litchi chinensis (LICH) fruits are staples in Haut-Katanga (DRC) and traditionally used in Lubumbashi to treat gastrointestinal, urinary and respiratory infections despite a lack of efficacy data. This study assessed the antibacterial activity of DAED and LICH fruit extracts against six pathogens—Escherichia coli, Salmonella typhi, Shigella sonnei, Staphylococcus aureus, Klebsiella pneumoniae, and Streptococcus pneumoniae—and simultaneously characterized their nutritional profiles, radical-scavenging capacity and phytochemical content (polyphenols, flavonoids, tannins). Antibacterial efficacy was determined by broth microdilution (MIC) and agar diffusion (inhibition zone diameters), antioxidant potential by DPPH assay, and nutritional–phyto-chemical composition by spectrophotometric quantification of dietary fiber, reducing sugars, vitamin E, minerals and bioactive groups. Both extracts exhibited strong antibacterial activity, notably against E. coli and K. pneumoniae (MIC 3.1–6.3 µg/mL; inhibition zones 20–21 mm), and potent radical-scavenging effects (IC₅₀: 3.1 µg/mL for DAED; 5 µg/mL for LICH). Nutritional analysis revealed elevated dietary fiber (20–27 g/100 g), vitamin E (10–14 mg/100 g) and zinc (11–18 mg/100 g), exceeding recommended daily intakes. Phytochemical screening detected flavonoids, tannins, steroids and terpenoids. DAED was distinguished by high lipid (53.4 g/100 g), potassium (444 mg/100 g), magnesium (149 mg/100 g) and total polyphenols (978 mg GAE/100 g) contents, whereas LICH was richer in total flavonoids (230 mg QE/100 g), tannins (40 mg GAE/100 g), carbohydrates (71 g/100 g) and calcium (300 mg/100 g). These findings provide the first scientific validation of DAED and LICH’s traditional antimicrobial applications in Lubumbashi and pave the way for standardizing fruit-based phytotherapeutics and isolating their bioactive principles.