In Vitro Antioxidant, Anti-Inflammatory, and Digestive Enzymes Inhibition Activities of Hydro-Ethanolic Leaf and Bark Extracts of Psychotria densinervia (K. Krause) Verdc

Psychotria densinervia hydro-ethanolic leaf extract (PHELE) and bark extract (PHEBE) were evaluated for antioxidant, anti-inflammatory, and inhibition of digestive enzymes activities. The antioxidant activity was characterized by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and total flavonoid content (TFC) assays. The anti-inflammatory activity was characterized by protein denaturation and antiproteinase tests, while the inhibition of the enzymes was assessed using alpha-amylase, alpha-glucosidase, lipase, and cholesterol esterase activities. PHELE presented low (p < 0.001) IC50 (59.09 +/- 5.97 mu g/ml) for DPPH compared with ascorbic acid (71.78 +/- 6.37 mu g/ml) and PHEBE (115.40 +/- 1.21 mu g/ml). The IC50 of PHELE (262.4 +/- 4.46 mu g/ml) and PHEBE (354.2 +/- 1.97 mu g/ml) was higher (p < 0.001) than that of catechin (33.48 +/- 2.02 mu g/ml) for ABTS. PHELE had high (p < 0.001) FRAP (341.73 +/- 21.70 mg CE/g) than PHEBE (150.30 +/- 0.32 mg CE/g). PHELE presented (p < 0.001) high TPC (270.05 +/- 7.53 mg CE/g) and TFC (23.43 +/- 0.032 mg CE/g) than PHEBE (TPC: 138.89 +/- 0.91 and TFC: 20.06 +/- 0.032 mg CE/g). PHELE showed antiprotein denaturation with IC50 (257.0 +/- 7.51 mu g/ml) (p < 0.001) and antiproteinase activity (74.37 +/- 1.10 mu g/ml) lower than PHEBE (316.1 +/- 6.02 mu g/ml and 177.6 +/- 0.50 mu g/ml), respectively. Orlistat inhibited lipase (p < 0.001) activity with IC50 (37.11 +/- 4.39 mu g/ml) lower than PHELE and PHEBE (50.57 +/- 2.89 mu g/ml and 62.88 +/- 1.74 mu g/ml, respectively). PHELE inhibited cholesterol esterase with IC50 (34.75 +/- 3.87 mu g/ml) lower than orlistat (54.61 +/- 2.56) and PHEBE (80.14 & PLUSMN; 1.71 mu g/ml). PHELE inhibited alpha-amylase IC50 (6.07 +/- 4.05 mu g/ml) lower than PHEBE (19.69 +/- 6.27 mu g/ml) and acarbose (20.01 +/- 2.84 mu g/ml). Acarbose inhibited alpha-glucosidase (p < 0.001) activity with IC50 (4.11 +/- 3.47 mu g/ml) lower than PHELE (24.41 +/- 2.84 mu g/ml) and PHEBE (38.81 +/- 2.46 mu g/ml). PHELE presented better antioxidant, anti-inflammatory, and enzyme inhibition activity than PHEBE.