DescriptionLycopene is an acyclic C40 non polar carotenoid found in tomatoes. In nature, the predominant form is the all-trans isomeric form which represents 80-97% of lycopene in tomato and tomato related products. However on consumption of tomato products, >50% of the lycopene is found in the cis isomeric form in the body, thereby implying that the cis isomeric form is the more bioavailable /bioactive form in the human body.
The major objective of our study was to validate the bioactivity of lycopene isomers. Three approaches were used to achieve this goal. 1). An ab initio computational model to study the structure of isomers. 2). Develop a method to isolate isomers. 3). Study antioxidant activity and cellular proliferation activity of isomers in in- vitro condition.
Computational modeling studies showed that lycopene isomers differ in their electronic distribution on the molecules. Cellular Antioxidant Activity (CAA) method showed that cis isomers have higher CAA compared to all-trans isomers.
The cellular proliferation assay known as the MTT assay indicated larger decrease in proliferation of cis isomer treated prostate cancer cells. The anti-inflammatory assay (measures the amount of nitric oxide (NO) produced by mouse macrophages (RAW 264.7)) showed marginal difference in activity between control and isomer treated cells.
Non-thermal processing techniques like High Hydrostatic Pressure (HHP) processing and Pulse Electric Field (PEF) were used to increase the yield of beneficial cis lycopene isomer in the processed product. The results showed an qualitative increase in cis isomer after non-thermal processing.
This study helps us get deeper insights on the activity of cis and all-trans lycopene isomers at a basic molecular level, which correlates to the activity at a chemical and biological level. Non-thermal processing methods like High Hydrostatic Pressure processing and Pulse Electric Field processing methods can cause lycopene isomerization. These can be used as alternative means of processing to get tomato products that can yield health benefits to the consumers.