Thesis (MSc) - Cyprus International University. Institute of Graduate Studies and Research Pharmacognosy

Thevetia peruviana have been used for its cardiotonic, anticancer, anti-inflammatory and
antidiabetic activities. The current study is aimed to evaluate the pharmacognostic and
biological activities of Thevetia peruviana leaf extract. The study is further designed to
evaluate some microscopic features, physicochemical, phytochemical, antioxidant and
antibacterial activities of the leaf extract. The microscopic analysis was conducted with
the aid of the microscope. The physicochemical analysis was done using standard
methods. The phytochemical test for the tannins, alkaloids, flavonoids, and other
metabolites were carried out using standard methods. The DPPH assay was used to
evaluate the free radical scavenging activity. The antibacterial activity was carried out
using the disk diffusion method. The microscopic study revealed the presence of paracytic
stomata surrounded by subsidiary cells and multicellular glandular trichomes. The
moisture content was 18.5%. The petroleum ether, alcohol and water-soluble extractive
values were 20%, 25% and 25% respectively. The phytochemical screening revealed the
presence of alkaloids, tannins, flavonoids and triterpenoids. The leaf extract of Thevetia
peruviana showed antibacterial activity on Escherichia coli and Staphylococcus aureus
with inhibition zones of 10.6 mm and 9.66 mm, respectively. The free radical scavenging
activity demonstrated by the extract was expressed in terms of the IC50 where the extract
had IC50 of 0.142 mg/mL and the ascorbic acid had IC50 of was 0.0296 mg/mL. The
antibacterial and free radical scavenging activities demonstrated by the extract have
validated the use of the plant for treatment of the claims of the use of the plant in traditional
medicine.