Efficacy of Crude Extract from Candle Brush (Senna didymobotrya) Leaves against Aspergillus niger in Reduction of Post-harvest Losses in Tomatoes

Abstract

Background: Senna didymobotrya grows naturally in East Africa and is commonly used to treat microbial infections by African communities due to the presence of various phytochemicals such as alkaloids, terpenoid, anthraquinones, tannins, saponins, phenols and flavonoids. Objective:  This study was conducted to evaluate the effectiveness of the crude extract of candle brush (Senna didymobotrya) leaves against Aspergillus niger in the reduction of post-harvest losses in tomatoes. Methods: A completely randomised design with two treatments, each replicated six times was used. In this study. Dried leaves were ground into a fine powder and extracted using the Soxhlet apparatus with 100% methanol. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the extract were determined against Aspergillus niger. The shelf life of tomatoes was determined by spraying the extract reconstituted in water at 0.4 g/ml and further analysed the total viable counts at three-day intervals and checking for the growth of mould, colour changes and odours as indicators of spoilage. Results: After extraction 22 g of the crude extract was obtained from the dried leaves The MIC and MFC of the methanol crude extract against Aspergillus niger were 0.04 g/ml. The shelf life of the treated tomatoes was 14 days while for the untreated was 9 days. T-test results at (P0.05) showed a significant difference between the treated and untreated samples based on the total viable counts. Conclusion: The crude extract of the candle brush inhibited the growth of Aspergillus niger in fresh tomatoes and also prolonged the shelf life of tomatoes for 14 days.  Further studies should be done to evaluate the market acceptability of the tomatoes.