Abstract:
Osbeckia octandra L. (DC.) is an endemic plant which belongs to the family
Melastomataceae and highly used in Sri Lankan Ayurvedic medicine. The aim of the present study
was to evaluate total phenolic (TP), flavonoid (TF) contents, in-vitro radical scavenging activity
and antioxidant activity of aqueous extract obtained from Osbeckia octandra L. (DC.) (Heen
bovitiya) leaves. The crude aqueous extract was prepared by soaking method in the dark conditions
from oven dried Heen bovitiya leaves collected from Galle District in Sri Lanka. The freeze dried
powder of the crude extract was obtained and subjected to preliminary phytochemical tests. TP
and TF contents of extract were determined by Folin-Ciocalteu assay and Aluminum chloride
colorimetric method respectively. In-vitro antioxidant activity was determined using 2,2-diphenyl 1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Results of the
preliminary phytochemical screening exhibited the presence of phenolic compounds, flavonoids,
tannins, terpenoids, phytosterols, saponins, alkaloids, carbohydrates, proteins and amino acids.
TP and TF contents of aqueous extract were calculated as 5356.501±59.552 mg Gallic acid
equivalents (GAE)/100 g dry weight (DW) of leaves and 2004.514±2.206 mg Catechin
equivalents (CAE)/100 g DW of leaves. Radical scavenging and antioxidant capacities for the
aqueous extract were 11.279±0.516 mmol Trolox equivalents/100 g DW and 33.366±0.674 mmol
Fe(II) equivalents/100 g DW of leaves. Results revealed that O. octandra leaves have a high TP
and TF content which is exhibited through its promising antioxidant activity. Hence, it was
concluded that O. octandra is a medicinally important herb with remarkable antioxidant activity
which could be used to address pathological states related to oxidative stress.
