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 α-amylase, α-glucosidase, lipase, and cholesterol esterase activities. PHELE presented low (p < 0.001) IC50 (59.09 ± 5.97 µg/ml) for DPPH compared with ascorbic acid (71.78 ± 6.37 µg/ml) and PHEBE (115.40 ± 1.21 µg/ml). The IC50 of PHELE (262.4 ± 4.46 µg/ml) and PHEBE (354.2 ± 1.97 µg/ml) was higher (p < 0.001) than that of catechin (33.48 ± 2.02 µg/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 µg/ml) (p < 0.001) and antiproteinase activity (74.37 ± 1.10 µg/ml) lower than PHEBE (316.1 ± 6.02 µg/ml and 177.6 ± 0.50 µg/ml), respectively. Orlistat inhibited lipase (p < 0.001) activity with IC50 (37.11 ± 4.39 µg/ml) lower than PHELE and PHEBE (50.57 ± 2.89 µg/ml and 62.88 ± 1.74 µg/ml, respectively). PHELE inhibited cholesterol esterase with IC50 (34.75 ± 3.87 µg/ml) lower than orlistat (54.61 ± 2.56) and PHEBE (80.14 ± 1.71 µg/ml). PHELE inhibited α-amylase IC50 (6.07 ± 4.05 µg/ml) lower than PHEBE (19.69 ± 6.27 µg/ml) and acarbose (20.01 ± 2.84 µg/ml). Acarbose inhibited α-glucosidase (p < 0.001) activity with IC50 (4.11 ± 3.47 µg/ml) lower than PHELE (24.41 ± 2.84 µg/ml) and PHEBE (38.81 ± 2.46 µg/ml). PHELE presented better antioxidant, anti-inflammatory, and enzyme inhibition activity than PHEBE.

Excelsanone, a new isoflavonoid from Erythrina excelsa (Fabaceae), with in vitro antioxidant and in vitro cytotoxic effects on prostate cancer cells lines.

A new isoflavonoid, excelsanone (2), was isolated from the ethyl acetate extract of Erythrina excelsa stem bark, together with three known compounds namely 6,8-diprenylgenistein (3), ß-sitosterol (1) and sitosteryl-ß-D-glucopyranoside (4). Their structures were elucidated using spectroscopic methods (HR-ESI-MS, NMR and IR) and by comparison with some literature data. The antioxidant activity of crude extracts and two isolated compounds was evaluated using free radical scavenging (DPPH) and Ferric Reducing Ability Power (FRAP) methods with catechin as standard. The results of the radical scavenging activity showed that excelsanone (2) has a moderate potential with an IC50 of 1.31 mg/ml. The cytotoxicity of compounds 2 and 3 as well as the ethyl acetate extract was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in two prostate cancer cell lines (DU145 and PC3). Excelsanone (2) induced a greater cytotoxicity in all tested cell lines, with a significant inhibition of DU145 cells growth in a concentration-dependent manner.