Inhibitory Effect on Human Platelet Aggregation, Antioxidant Activity, and Phytochemicals of Canna warszewiczii (A. Dietr) Nb. Tanaka

Background: Canna warszewiczii (A. Dietr) Nb. Tanaka has been traditionally used to treat heart diseases in Vietnam, but there is a lack of scientific evidence. Objectives: This study investigated the inhibitory effect on human platelet aggregation, antioxidant activity, and main phytochemicals of fractions from the aerial and rhizome parts of the plant. Materials and Methods: Human platelets were prepared and incubated with different fraction doses (0.33, 0.75, and 1.5 mg/mL). Platelet aggregation was triggered by different agonists (adenosine diphosphate [ADP], collagen, and ristocetin). 2,2‑diphenyl‑1‑pycrylhydrazyl (DPPH) and 2,2’‑azino‑bis (3‑ethylbenzothiazoline‑6‑sulfonic acid) (ABTS) assays were done to test the free‑radical scavenging activities. Spectrophotometry assays using Folin–Ciocalteu and aluminum chloride were used to determine total flavonoid content (TFC) and total polyphenol content (TPC). The phytochemical screening was also implemented. Results: The n‑hexane, dichloromethane, and ethyl acetate (EA) fractions from both the rhizome and aerial parts significantly inhibited ADP‑, collagen‑, and ristocetin‑platelet aggregations and decreased significantly the area under the platelet aggregation curve and aggregation velocity in a concentration‑dependent manner, but the water fractions did not. The EA fractions showed the strongest DPPH and ABTS scavenging activity and highest TPC and TFC. Organic fractions contained variable bioactive compounds: flavonoids, polyphenols, glycosides, cardiac glycosides, coumarins, steroids, emodols, tannins, and cholesterols. Conclusion: The plant extracts or fractions could be used in the preparation of functional foods or supplements with antioxidant and antiplatelet activity. It is also a good candidate for searching novel bioactive compounds used in pharmaceutical industries for the development of antiplatelet and antioxidant agents to prevent and/or treat heart and oxidative stress‑related diseases.