According to Ayurveda, a system of medicine that uses plant-based medicines to cure diseases, Ashwagandha or Withania somnifera is known to have therapeutic properties such as being a potent antimicrobial and an excellent anti-cancer agent. The roots and leaves of this plant, in particular, contain metabolite compounds such as steroids, saponins, flavonoids and alkaloids which are used to make medicines. Hence, Ashwagandha is now being grown as a commercial crop. However, it is difficult for the seeds to germinate and survive, and often, there is a long wait between planting and harvesting, impeding the successful medicinal use of the plant on a large scale.
In a study, researchers from the Guru Nanak Dev University, Amritsar, India and National Institute of Advanced Industrial Science & Technology, Japan, have shown that cultivating Ashwagandha organically with vermicompost can enrich the soil and help in the germination and growth of the plant. The study, jointly funded by the Department of Biotechnology, India and National Institute of Advanced Industrial Science & Technology (AIST), Japan, was published in the journal PLoS ONE.
Ashwagandha is well adapted to tropical climate and is widely grown in the Indian subcontinent, South Africa and the Mediterranean and Middle Eastern countries. In this study, the researchers have used vermicompost—a mix of organic waste composted by earthworms and microorganisms—for growing the plant. It is rich in organic and inorganic nutrients necessary for plant growth, most of which are present in the liquid components of vermicompost, namely the leachate and the ‘tea’.
The researchers investigated if vermicompost, including its leachate and tea, could increase seed germination, growth and the metabolite content of Ashwagandha, using an environmentally sustainable propagation system. They found that successful seed germination increased when the seeds were soaked in the leachate and the tea for 12 hours. Besides, when vermicompost was used, these seeds grew well too. The researchers also observed increased leaf and root mass, and earlier onset of flowering and fruiting in Ashwagandha cultivated using vermicompost and its leachate. The most significant effect of this combination was seen on the leaves, which are the primary sources of metabolites from Ashwagandha.
The study also explored the anti-cancer properties of the active ingredients from Ashwagandha. The extracts from the leaves of the plants that germinated from seeds soaked in the leachate and cultivated with a combination of the vermicompost and the leachate showed higher anticancer activity. However, the quantity of vermicompost used was a determining factor, found the study. Plants grown with only vermicompost and no soil showed lower anti-cancer activity and those cultivated with a combination of up to 60% vermicompost and leachate showed good anticancer activity. The researchers attribute this anti-cancer property to the increased amount of compounds called withanolides, which are produced when vermicompost and its leachate were used.
The study provides sufficient evidence to shift the cultivation of Ashwagandha to an organic and environment-friendly system. “Organic cultivation of Ashwagandha will lead to its improved yield, germination and growth, and enhance its potential to be used as a food and plant-derived medicinal agent. This system is not be limited to the cultivation of Ashwagandha but can also be used for other medicinally important plants”, conclude the authors.