Abstract:
The rocket ( L.) is a medicinal herb belonging to family Brassicaceae
which highly consist of antioxidant, anticancer properties, reducing risk
of cardiovascular and cognitive disease. Despite the medicinal importance, Avicenna,
farther of Unani medicine considers that the air rise from the fields of vegetables,
particularly those in which cabbage and rocket seeds (Jirjir) are grown, is unfit for
inhalation. In this regard, we examine the current knowledge on plant photoprotective
measures at high light intensities, triggering biosynthesise of toxic photo products in
response to stress. Plants receive light energy as photons which use for driving
photosynthetic process.However, the excess photons captured are rapidly dissipated as
heat by photochemistry to avoid over excitation of chlorophyll molecules. Once this
process delays, excited chlorophylls interacts with oxygen molecules and form an
extremely reactive singlet oxygen( O )and other classes of reactive oxygen species
(ROS) such as superoxide ( O * ), hydrogen peroxide (H O ), hydroperoxyl radicles
(HO ) and hydroxyl radical (OH*)which cause photo oxidative stress by damaging
membrane lipids, protein and nucleic acids.Although, to alleviate such situations,
carotenoids and xanthophyll play role in photoprotective mechanisms eliminates ROS
by re-scavenging enzyme activities viz; superoxide dismutase and ascorbate
peroxides. However, the imbalance between the production of ROS and antioxidant
defence has been reported in rocket plants. In recent studies, it has been revealed that
H O is excessively synthesised in tissues when exposed to stress condition. Moreover,
the alveolus functions are impairedby ROS in premature and new born babies.Hence,
these findings partly validate the Avicenna's theory
