Bioactive Chemicals and Biological Activity of Tropaeolum majus L. and the Importance of Trichoderma spp. in the Cultivation of This Species

Tropaeolum majus L. is a popular ornamental plant. All parts of T. majus plant (flowers, leaves, and seeds) are edible and are appreciated for their pungent taste, although their chemical composition varies. T. majus is known for its many health benefits. It is a source of trace elements and bioactive compounds that are easily absorbed by the human body. The flowers of T. majus contain flavonoids from the flavone and flavonol groups, as well as their glycosides, which exhibit antibacterial, antifungal and antiviral activity. They also inhibit the activity of certain enzymes. Among the flavonoids, the flowers and leaves of T. majus contain derivatives of kaempferol and quercetin. Flavonoids also include anthocyanins, which are responsible for the color of T. majus flowers. In red flowers, delphinidin predominates; in orange flowers, pelargonidin; and in yellow flowers, pelargonidin and delphinidin are present in similar amounts. In the flowers of T. majus, seven carotenoids have been identified: violaxanthin, antheraxanthin, lutein, zeaxanthin, α, β and γ-carotene. In the leaves, however, lutein, violaxanthin, β-carotene and neoxanthin were detected. In T. majus, the presence of two glucosinolates has been reported: glucotropaeolin and sinalbin. The flowers and leaves of T. majus also contain both macroelements (N, P, K, Ca, Mg, Na) and microelements (Fe, Mn, Cu, Zn, Mo), and essential oils which have anti-cancer, antibacterial, and antiviral properties. The quality and flowering of T. majus are enhanced by fungi of the Trichoderma genus, which is important both ecologically and in terms of increasing the yield of raw material extracted from the plant. T. aureoviride, T. hamatum, and T. harzianum stimulated the flowering of the T. majus ‘Spitfire’. The plants treated with T. harzianum after being planted in pots flowered the most abundantly. Trichoderma spp. caused the plants to grow more intensively, producing longer and more leafy shoots with a greater number of offshoots. Trichoderma spp. stimulated the uptake of macronutrients, except for P. In the case of Ca and Na, this phenomenon was only observed in plants treated with T. aureoviride and T. hamatum, and for Mg, only when T. hamatum was applied to sown seeds. As for the developed root systems, as far as the micronutrients are concerned, Trichoderma spp. stimulated the uptake of Zn and Mn. Additionally, there was a higher Fe content in the plants treated with T. harzianum on both dates and T. aureoviride after planting the plants in pots.