Phytochemicals, antioxidant and antibacterial properties of a lichen species Cladonia digitata
Antioxidant activity assessment was performed using the free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and reducing power assay. Phytochemical screening was done using chemical tests. Antibacterial activities of Cladonia digitata were determined by a disk diffusion method at concentrations of 0, 10, 50 and 100% (v/v) against pathogenic bacteria, Eschericia coli, Clostridium perfringens and Staphylococcus aureus. Standard cotrimoxazole (10 μg/ml) was used as a positive control. C. digitata revealed the presence of alkaloids, tannins, saponins, cardiac glycosides, flavonoids, anthraquinones and steroidal terpenes. The results of antioxidant activity indicate a concentration dependent activity. C. digitata extract showed better free radical scavenging activity than ascorbic acid and quercetin. There was no significant difference (T-test, p = 0.05) in the antioxidant activity between the extract and those of ascorbic acid and quercetin as assessed by the reducing power assay. The highest antibacterial activity was 16.1 mm diameter of zone inhibition observed against Clostridium perfringens followed by 15.5 mm against Staphylococcus aureus at the concentration of 100 and 50%, respectively. The results reveal that the tested extract consisted of several bioactive compounds, significant antioxidant and antimicrobial activity. The present results scientifically authenticate the use of C. digitata in folk medicine.
Keywords: Phytochemicals, antioxidant, antibacterial, Cladonia digitata