Tehran University Medical Journal

Herbal essential oils are volatile, natural, complex compounds formed by medicinal plants as secondary metabolites. As reported by international organization for standardization (ISO), the term "essential oils" (EOs) is defined for a product obtained from vegetable raw materials or fruit using distillation with water or steam. The EOs are generally complex mixtures of volatile organic compounds include hydrocarbons (terpenes and sesquiterpenes) and oxygenated compounds (alcohols, esters, ethers, aldehydes, ketones, lactones, phenols, and phenol ethers) compounds. In medicinal plants, the EOs chemical profile usually very varies because of both intrinsic (sexual, seasonal, ontogenetic, and genetic variations) and extrinsic (ecological and environmental aspects) factors, also the EOs composition differs not only in the number and type of molecules but also in their stereochemical structures, and can be very different according to the extraction method. EOs represents a “green” alternative in the nutritional and pharmaceutical fields due to reported antimicrobial, antioxidant, anti-inflammatory and anticancer properties thus, in recent times; EOs has gained great popularity as consumers have developed a particular ever-growing awareness toward the use of natural ingredients, especially in food and household. Therefore, the present review provides a comprehensive summary on the method of preparation of EOs from medicinal plants, chemical composition analysis, their biological and pharmacological effects and their potential benefits on health level. Present information was compiled using keywords “Essential oil, Medicinal Plants and Natural additive in scientific database as Science Direct, Elsevier, PubMed, Google scholar and SID, until 2005 to 2015. EOs have great antimicrobial activity and mostly destroy bacteria, fungi and viruses without harmful effects on consumer’s health. Finding of this study showed that the Thymol, α-Pinene, β-Pinene, Cumin Aldehyde, Carvacrol, Germacrene, Linalool were the main components. Also, EOs have antioxidant, anti-inflammatory and many other pharmacological properties which enhance their potential application. EOs have potential biological and pharmacological activities and so have many applications in pharmaceutical and food industries.

Background: Considering the high death rate of patients on the transplant waiting list, one of the most important ethical challenges of organ transplantation is the lack of transplant organs and different approaches to cover it.
Methods: The ethical issues of organ transplantation have been frequently reviewed recently.
Results: Currently, there are 4 sources for organ transplants, which are: a) organ transplant from animal to human b) transplant from a living donor c) transplant from a brain-dead donor d) transplant from a cardiac-dead donor or donors without a heartbeat, and tissue engineering research continues to prepare a transplantable organ. Each of them has its own limitation and specific consideration. In Iran, organ procurement from brain-dead donors and living donors are the most important sources. Many approaches have been considered to increase the number of procured organs from brain-death cases in the world, but have not yet been able to reduce the gap between supply and demand. Therefore, since the 1980s, the program of organ transplantation from cardiac death (donors with irreversible cardiac arrest) in the world has been reviewed again. Based on the classification of cardiac arrest patients, they are placed in two general categories: uncontrolled and controlled. In a controlled condition, death is predictable, and organ removal is possible by eliminating planned medical interventions and patient support. But in the uncontrolled state, death occurs accidentally, which is more likely to prolong the duration of hot ischemia. Italy's organ donation group has recently introduced type 6 deaths in patients on ECMO, which is mentioned as a semi-controlled group. This group is called donors with abnormal blood flow versus brain-dead donors with normal blood flow. In this study, ethical considerations for organ donation from NHBD were discussed. Regarding the procurement of organs from non-heart beating donors, there are many ethical considerations that include both the donors and the recipients. Considering that the clinical conditions of the brain-dead donors are sometimes very unstable, cardiac arrest may occur before organ harvesting. In these cases, donation after cardiac death is an option.
Conclusion: It is necessary to regulate the ethical considerations for organ procurement from NHBD