Variability of Bio-active and Other Chemical Constituents in Soursop Fruits (Annona muricata L.) Grown in Sri Lanka

Soursop has been reported to be effective for the treatment of a variety of diseases, including cancer prevention. Phenolic acids and flavonoids are the most important biologically active compounds in plants in terms of neutralizing reactive oxygen species (ROS). The bio-active compounds in plants are genetically determined with strong influence from environmental factors on their quality and quantity. Soursop is cultivated in all over the country, except few areas in the Nuwara Eliya district. Soursop fruits were collected from selected locations in the country to determine the variability of some selected chemical constituents in them. Soursop samples collected from different locations were grouped into three clusters. The biochemical properties namely, total phenolic content (TPC), total flavonoid content (TFC), vitamin C and total soluble solids (TSS) in the fruits significantly (p=0.0001) differed among the crop growing areas. Soursop fruits collected from crop-growing areas in seven agro-climatic zones with 14 different soil types. Soursop fruits collected from locations in the Up-country (>900 m amsl) area exhibited significantly (p=0.0001) higher amounts of TPC and TFC compared to the fruits from other areas. Methanolic extracts yielded 202-309 mg gallic acid equivalent (GAE) of total phenolics and 69-91 mg quercetin equivalents (QE) of total flavonoids in 100 g of fresh fruit.