Evaluation of antioxidant activity of the crude ethanolic extract from the bark of Cinnamomum mercadoi

Kalingag (Cinnamomum mercadoi) is a native plant of the Philippines that has long been used in traditional medicine. Because of its indigenous nature, research on this plant remains limited. This research evaluated the phytochemical content and antioxidant properties of a crude ethanolic extract from Cinnamomum mercadoi bark. The plant bark collected from Davao Occidental was thoroughly cleaned with distilled water to remove any adhering dirt, air-dried for a week in the shade, and then pulverized with a Wiley mill. The bark was then subjected to Soxhlet extraction for 6 hours, and the pooled extracts were concentrated for 5 hours at 60°C in a rotary evaporator to yield a green, syrupy substance. The extract was tested for phytochemical content, followed by Fourier Transform Infrared Spectroscopy (FTIR) for confirmation of the subsequent results by determining the functional groups that comprise their structure, before being assessed using the DPPH assay for free radical scavenging. The phytochemical screening and subsequent FTIR analysis revealed important metabolites such as tannins, glycosides, phytosterols, and terpenoids, all of which contribute to the antioxidant activity of the crude ethanolic extract. In the DPPH assay, the extract demonstrated concentration-dependent activity (IC₅₀ = 85.7627 µg/mL) compared to the gallic acid (IC₅₀ = 4.1818 µg/mL). Such findings highlight the importance of purifying and isolating specific compounds to boost the plant's antioxidant activity. To maximize its value, further study into other parts of the plant is recommended.