Phytochemical, Acute Oral Toxicity, and In-Vitro Anti-Diabetic Activity Screening of the Methanol Leaf Extract of Landolphia owariensis (Apocynaceae)

Medicinal plants have been explored for the treatment of numerous health problems from the era of complete absence of scientific medical knowledge to present day medicine. Therefore, the objective of this paper was to investigate the phytochemical, acute oral toxicity, and in-vitro anti-diabetic activity of the methanol leaf extract of Landolphia owariensis (Apocynaceae) using appropriate standard methods. The phytochemical investigation of the leaf extract of Landolphia owariensis revealed the presence of saponins, alkaloids, phenolics, flavonoids, terpenoids, and anthraquinones, while tannins were absent. Acute toxicity screening showed that the extract was toxic at high doses with LD50 of 3808 mg/kg body weight. The anti-diabetic investigation showed that the leaf extract of Landolphia owariensis exhibited mild-moderate α-amylase inhibitory activity. The present study has shown that the methanol extract of the leaf of Landolphia owariensis possess anti-diabetic activity in vitro as evaluated by its α-amylase inhibitory activity. However, the therapeutic use of the plant may be limited by its potential toxic effect, especially at high doses.