Phytochemical and Safety Evaluation of Hydroethanolic Leaf Extract of Tecoma stans (L.) Juss. ex Kunth

Tecoma stans (yellow bell) is a popular ornamental plant mostly found in the tropical regions. It is reported to have significant pharmacological activity and has gained attention by natives of various cultures. This study focused on the phytoconstituents screening, antioxidant activity, and heavy metal analysis as well as the acute and subchronic toxicity of the hydroethanolic leaf extract (TSE) using standard methods. The presence of flavonoids, alkaloids, cardiac glycosides, saponins, coumarins, and terpenoids in the raw leaf of the plant was observed while the hydroethanolic extract contained coumarins, saponins, cardiac glycosides, and flavonoids. The DPPH percentage scavenging activity of the crude extract was 64.32% while the fractions, ethyl acetate (55.26%), methanol (60.72%), and hydro (36.97%.), gave varying activities. The UV-Vis and FT-IR indicated the presence of alcohols, phenols, alkanes, alkenes, carbonyls (general), aliphatic amines, aromatics, ketones, ethers, esters, carboxylic acids, alkyl halides, saturated aliphatic acids, 1° and 2° amines, amides, and α,β-unsaturated aldehydes. The heavy metal analysis showed a high level of iron (Fe) and zinc (Zn) in the raw leaf. The median acute toxicity (LD(50)) of the extract was determined to be <5000mg/kg body weight in mice. Subchronic use for 28 days resulted in significant weight gain, reduction in platelet levels, decrease in WBCs, and increase in blood glucose compared to the normal. TSE caused no adverse effects on vital organs. No mortality was recorded. The hydroethanolic extract of T. stans could therefore be considered safe in moderate doses.