Ocimum sanctum Linn. Tulasi, family Labiatae is a sacred plant, to which several medicinal properties are mentioned in Aurveda, the oldest system of medicine. Apart from its medicinal importance it is being worshiped all over India as a plant which provides an antipollutant atmosphere and a fresh cyclic dose of oxygen.
The chemical analysis revealed that the plant parts contain essential oils: eugenol 73.2%, carvacrol 3.2%, citronella 15.7%, citral-aldehyde 68%, plus phenol and acetic acid. In addition to this, the presence of esters (4.8%) such as methyl heptenone and citronella was also revealed.
The wide range of organic constituents play an important role in the metabolism of the plant and it is very interesting to note that the evolution of oxygen, even in absence of sunlight, is a phenomenon in green plants. The continuity of oxygen evolution is due to a specific enzyme, cyclo-oxygenase, which carries out the pericyclic mechanism.
II has been established as fact that the evolution of ozone along with oxygen during photolysis of water in the presence of sunlight gives an impetus for a pericyclic mechanism called auto-oxidation. Conversely, the dissociation of molecular oxygen by absorption of ultraviolet radiation from the sun has important effects on the composition of atmospheric oxygen. This monatomic oxygen reacts with oxygen to form ozone, O-3.
The presence of aldehydes, ketones and esters in the Ocimum plant creates many metabolic interreactions to give rise to substitutions, which also result in the formation of oxides, peroxides and dioxides. The chemical combinations lead to the formation of a series of vapours releasing the oxidised gases through the stomata of the leaves and also absorbing a net amount of posisonous gases in return from the surroundings.
The controlled greenhouse experiments proved that a single plant of Ocimum sanctum can release 0.09 mi of oxygen per hour and 0.006 mi of ozone, and can replace the pollutants by absorbing 0.08 mi per hour. The efficiency of the plant seems to be negligible but the process continues for 24 h, day and night, without disturbing the natural process of the stomatal mechanism.
The plant is of great importance in the modern world of pollution where we are suffocating from vapours of SO, carbon monoxide and many poisonous gases in our day-to-day life.
It has been experimentally proven that one plant of Ocimum sanctum can take care of an area of 100 sq ft, keeping the area clean and nonpolluted for 24 h. This is due to the evolution of oxygen, cyclic transformation of ozone and peroxides, and vapours with organic contents, which replace and absorb pollutants by specific methods.
In conclusion, this unique mechanism of continuity in oxygen formation, ozone formation, and the vapours of essential oils makes this plant, Ocimum sanctum or tulsi plant, an natural antipollutant machine for modern civilization. It can purify the area slowly but surely without disturbing the natural equilibrium.