Phytochemical screening, antioxidant activity and toxicity of the orchids Prosthechea cochleata and Prosthechea livida-A preliminary study

Abstract

Phytochemical composition, antioxidant, and toxic effects of two orchid (Prosthechea cochleata and Prosthechea livida) were examined in their different hexane and dichloromethane/methanol extracts of leaves, pseudobulbs, rhizome and roots.  Phytochemical screening reveals the presence of alkaloids, coumarins, flavonoids, saponins, steroids and terpenes except for anthracene derivatives in P. livida and tannins in both species. Results showed exhibited significant toxicity against brine shrimp with an LC₅₀ values ranged from 3 to 54 µg/ml in 24 h.  Finally, the results of the antioxidant test in yeast (Saccharomyces cerevisiae) showed that CH₂Cl₂:MeOH extract of P. cochleata root extract presented the most efficient protective antioxidant percentage (%PA), with 20 µg/mL, displaying a cell viability of 68.58%. In P. livida case, rhizome extract presented the most efficient %PA, with 1000 µg/mL, with a cell viability of 65.82%.  The results evidenced the toxicity of  Prosthechea cochleata and Prosthechea livida and reveals potential antioxidative of extracts.