Effect of some growth stimulators on productivity, chemical and biological properties of Coleus amboinicus Lour. Cultivated under desert conditions

Abstract
During the two successive seasons, 2020 and 2021, this investigation was carried out on Coleus amboinicus to study the effect of spraying some plant stimulators on growth, yield, active constituents, and biological activities. The experiment included six foliar spray treatments (control, moringa extract, blue green algae extract, compost tea, active dry yeast extract, and Azolla extract). The applications were arranged in a randomized complete block design with three replicates. The measured data involved growth and yield parameters (plant height, fresh weight of herb per plant, fresh yield of herb per hectare, dry weight of herb per plant, and dry yield of herb per hectare), chemical parameters (essential oil percent, oil content per plant, oil yield per hectare, oil composition, total phenolic content, total flavonoid content), and biological activities (antioxidant and anticancer). The results represented that spraying C. amboinicus with all stimulators significantly increased growth, yield, essential oil percent, oil content per plant, and oil yield per hectare over control. The significant promising treatment was sprayed with blue green algae extract, which recorded the best traits. Moreover, the results showed that using blue green algae extract revealed the highest total phenolic content in the plant while utilizing compost tea represented the highest total flavonoid content. Consequently, using compost tea enhanced in vitro antioxidant and anticancer activities of C. amboinicus.