Triguna is an sanskrit term made up with the combination of two sub words i.e. Tri (three) and Guna (qualities). So the word Triguna stands for the three qualities present in the human body.
As there these are three qualities present in the human body, then is there any simalarity to Tridosha (the three humors of human body)? As the human body is divided into two part i.e. Sthula shareera (physical body; which is visible from the eyes) and the Sukshma shareera (concious body; invisible from the eyes). These three doshas i.e. Vata, Pitta and Kapha after vitiation causes the disease also they plays a part in forming the Prakruti (nature) of an particular individual, also they are assumed with the physical form. Whereas the Trigunas are the qualties which is realted with the Sukshma shareera, and relate with the mental or concious level. They are also called as Mansika dosha/ Mansika tridosha (humors at the mental level). As Tridosha will form the physical nature especially of the human body whereas the Trigunas form the mental nature of the human.
As the Ayurveda theories mainly based upon the Gunas/ qualties of the subject or matter, so Trigunas have their distinct qualties.
Here Sattva is the only Guna or dosha rahita (pure) mansika dosha; whereas other two are not like Sattva. Its qualities are like goodness, calmness and harmonious etc. It will gives high intellectual power to the body as well as it will helps the person to lead a meaningfull life without much pain. Because of this Guna only a person is able to attain the high quality of conciousness, which helps him to understand the life in a better way and to attain the Nirvana (moksha/ enlightenment).
It is also called as the Rajas guna or Raja dosha, it is responsible for the activity, passion and movement etc. in the human form. It helps the person not to stop at a place and also let him enjoy the materialistic life. This Guna will move the person towards the never ending wordly fruits. Which never let the person to come out from the dilemma of the life and because of that he will never able to get the Nirvana.
As the Sanskrit meaning of this term is darkness, so it works as the same and leads the person towards the darkness without ray of light (which can also be uderstood by the Gyan/ light). It is responsible for the inertia, laziness and ignorance etc. which leads the person away from the reality of truth or life, which finally move him far away from the Nirvana.
Only the Sattva Guna is helps the person to attain the Moksha (enlighntment) and help him to comes out from Rebirth/ transmigrations/ reincarnation. But they all present in the human body as per their Karma, and a person will increase his sattva Guna to reach the final destination of the soul i.e. Moksha as per Hindu texts.
