Abstract

Medicinal plants are good sources of bioactive compounds that guards the body against cancer and chronic ailments. A lot of studies have been done on medicinal values of higher plants but less on marine sources and wild non-edible mushrooms. The study aimed to assess the antioxidant activity, total flavonoid and total phenolic content from selected Kenyan medicinal plants, sea algae and mushrooms. The plants were selected based on their availability and folklore medicinal value. The antioxidant activity of the extracts was assessed using 2, 2-diphenylpicryl-1-hydrazyl (DPPH) free radical scavenging method. The total phenolic analysis was achieved using the Folin-Ciocalteu technique while the flavonoid content was determined by the use of aluminium chloride calorimetric method. The total phenolic content was expressed as gallic acid equivalent (GAE) and flavonoid content as quercetin equivalent (QE). Ganoderma applanatum had the highest scavenging ability (95.56%), while Urtica dioica leaves had the lowest (11.99%) at 0.3 mg/ml of extract. G. applanatum also had the lowest IC50 (<0.025 mg/ml), an indication that it had the highest antioxidant potential. Ganoderma lucidum showed the highest total phenolic content (GAE/g) of 156 ± 3.45 mg and U. dioica showed the lowest. G. lucidum also showed the highest total flavonoid content (QE/g) of 31.16 ± 0.04 mg. The study reveals that the Kenyan plant species can be potential sources of new natural antioxidants.

Key words: Antioxidant activity, DPPH, Folin-Ciocalteu, IC50, flavonoids, phenolic content.