Phytochemical investigation and antioxidant and anti-inflammatory activities of three Knema species with emphasis on Knema lenta methanolic extract

The anti-inflammatory and antioxidant activities of branch and leaf extracts from Knema globularia, K. tonkinensis, and K. lenta were evaluated in lipopolysaccharide-stimulated RAW 264.7 macrophages. Antioxidant capacity was assessed by DPPH and ABTS assays, together with total phenolic and flavonoid contents. K. lenta leaf extract showed the highest phenolic (157.70 ± 5.68 mg GAE g⁻¹) and flavonoid (175.02 ± 4.45 mg QE g⁻¹) contents, and the strongest antioxidant activity (DPPH IC₅₀ 26.17 ± 0.82 μg mL⁻¹; ABTS IC₅₀ 34.20 ± 1.75 μg mL⁻¹). It also significantly inhibited NO production (IC₅₀ 22.07 ± 0.35 μg mL⁻¹), indicating potent anti-inflammatory potential.