Salicylic acid (SA) is a phenolic phytohormone and is found in plants with roles in plant growth and development, photosynthesis , transpiration , ion uptake and transport.  SA is involved in endogenous signaling, mediating in plant defense against pathogens .  It plays a role in the resistance to pathogens by inducing the production of pathogenesis-related proteins .  It is involved in the systemic acquired resistance in which a pathogenic attack on one part of the plant induces resistance in other parts. The signal can also move to nearby plants by salicylic acid being converted to the volatile ester, methyl salicylate . 
The castor seed contains ricin , a toxic enzyme. Heating during the oil extraction process denatures and deactivates the enzyme. However, harvesting castor beans may not be without risk.  Allergenic compounds found on the plant surface can cause permanent nerve damage, making the harvest of castor beans a human health risk. India, Brazil and China are the major crop producers and the workers suffer harmful side effects from working with these plants.  These health issues, in addition to concerns about the toxic byproduct (ricin) from castor oil production, have encouraged the quest for alternative sources for hydroxy fatty acids.   Alternatively, some researchers are trying to genetically modify the castor plant to prevent the synthesis of ricin. 
Why a report on castor oil? Castor oil is one of the most versatile plant oils. Its unique chemical structure makes it useful in a wide number of industries and applications. Castor oil is fast becoming one of the most sought after plant oils, owing to its rich properties and variety of end-uses. Currently, it is being used by industries from pharmaceuticals to lubricants. With biopolymer and bio-fuels industries picking up a lot of steam in the last couple of years, the potential for castor oil to play a much larger role in the world economy had increased dramatically. While the castor oil industry is over five decades old, there has been considerable interest shown in this industry in the last few years. Leading countries from practically every continent (North & South America, Europe, Asia, Africa and Oceania) are showing renewed interest in the castor crop.