Understanding how the environment and production and cultivation practices influence the composition and quality of food crops is fundamental to the production of high-quality nutritious foods. In this 3-year study, total phenolics, percent soluble solids, ascorbic acid, and the flavonoid aglycones quercetin, kaempferol, and luteolin were measured in two varieties of tomato (Lycopersicon esculentum L. cv. Ropreco and Burbank) and two varieties of bell peppers (Capsicum annuum L. cv. California Wonder and Excalibur) grown by certified organic and conventional practices in a model system. Significantly higher levels of percent soluble solids (17%), quercetin (30%), kaempferol (17%), and ascorbic acid (26%) were found in Burbank tomatoes (fresh weight basis; FWB), whereas only levels of percent soluble solids (10%) and kaempferol (20%) were significantly higher in organic Ropreco tomatoes (FWB). Year-to-year variability was significant, and high values from 2003 influenced the 3-year average value of quercetin reported for organic Burbank tomatoes. Burbank tomatoes generally had higher levels of quercetin, kaempferol, total phenolics, and ascorbic acid as compared to Ropreco tomatoes. Bell peppers were influenced less by environment and did not display cropping system differences.

Annona muricata Linn. (soursop) plant is a medicinal plant that has been utilized in folk medicine for treatment of infectious and inflammatory diseases. This study aimed to determine the phytochemicals content, total phenolic and flavonoid contents and antioxidant activities of A. muricata leaves. Antioxidant activity was performed via 2, 2’-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenyl- 1-picrylhydrazyl (DPPH) radical scavenging assays. The phytochemical was extracted separately with distilled water and 96% ethanol by maceration. The results show that a wide variety of pharmacologically active compounds such as alkaloids, coumarins, tannins, flavonoids, carbohydrates, phenols, terpenoids, saponins were present in the leaves of A. muricata. The total phenolic and flavonoid content of ethanol extract in A. muricata leave achieved 609.08±5.82 mgGAE/g and 209.52±1.88 mgQE/g, respectively. The antioxidant activity of the ethanol extract of A. muricata was correlated with total phenolic and flavonoid content with values IC50 of 20.75±0.28 μg/ml, 12.84±0.21 μg/ml for DPPH and ABTS scavenging activity, respectively.