Pharmacognostic, antioxidant and antimicrobial activities of Solanum aethiopicum fruits

Abstract

Antimicrobial resistance is a serious global health problem caused by microorganisms that no longer respond to existing antibiotics. Despite years of drug development, this challenge continues to worsen. In recent years, natural products from plants have gained attention because they can be effective and often have fewer side effects than synthetic drugs. This study aimed to evaluate the pharmacognostic, antioxidant, and antimicrobial activities of Solanum aethiopicum fruits. Fruits were collected, authenticated, dried, and powdered. Microscopic and physicochemical analyses followed WHO guidelines. Methanolic extracts was prepared by cold maceration. Phytochemical screening was performed using standard procedures. Antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Thin-layer chromatography (TLC) was used for chemical profiling. Antimicrobial activity against Escherichia coli and Aspergillus niger was assessed by agar well diffusion. Minimum inhibitory (MIC), bactericidal (MBC), and fungicidal concentrations (MFC) were determined. Chemomicroscopy revealed starch grains, calcium oxalates, lignin, tannins, mucilage, and suberized walls. Physicochemical evaluation showed high extractive values and low moisture content. Phytochemical analysis detected alkaloids, flavonoids, saponins, tannins, steroids, triterpenes, and cardiac glycosides. TLC revealed five spots with Rf values between 0.22 and 0.92. Antioxidant activity was concentration-dependent, with maximum inhibition of 93.4% at 1000 µg/mL (IC₅₀ = 43.88 µg/mL). The extract showed moderate antibacterial activity against E. coli (12–16 mm) and weak antifungal activity against A. niger (6–14 mm). MIC and MBC for E. coli were 125 µg/mL, while MFC for A. niger was 6.25 µg/mL. Result obtained in this study have indicated that S. aethiopicum fruits contain bioactive compounds with strong antioxidant and moderate antimicrobial activities, supporting their potential for pharmaceutical use.