Insight into the antioxidant activities of ten Fabaceae plant species that are medicinally used by the Aucan Tribal Peoples from the Republic of Suriname (South America).

Fabaceae are associated with a high antioxidant activity (AA) and a high total phenolic (TPC), total flavonoid (TFC), and selenium content (SeC). In this study, the aqueous extracts from ten Fabaceae species that are medicinally used by the Aucan Tribal Peoples from Suriname (South America), were evaluated for AA using a DPPH and a FRAP assay, and for TPC, TFC, and SeC using Folin-Ciocalteu's, an AlCl3 colorimetric, and an azure B-based method. Associations between pairs of these variables were determined by Pearson correlation coefficient. One-way ANOVA with post-hoc Tukey's test was used to evaluate the data for statistically significant differences (p < 0.05). The I. stipularis (bark), C. guyanensis (bark), A. jupunba (twigs), and M. urens (fruit) extracts had the highest DPPH IC50 values (36 - 70 µg/mL) and FRAP values (346 - 573 µM FeE/100 µg) and the highest TPC (25 - 41 GAEq/100 µg), TFC (21 - 39 REq/100 µg), and SeC (4 -17 µg/g). The values for the T. indica (leaf), P. macroloba (bark), M. pigra (whole plant), S. quinquangulata (leaf), A. sensitiva (whole plant), and L. leucocephala (leaf) extracts were > 10-fold lower. AA, TPC, TFC, and SeC correlated well with each other (correlation coefficient ≥ 0.83, p ≤ 0.0030). Thus, AA, TPC, TFC, and SeC may represent important determinants of the health benefits of the former four samples but not of the others. Future studies should focus on the precise contribution of AA, TPC, TFC, and SeC to the therapeutic value of medicinal Fabaceae.

Beneficial effect of medicinal plants on the contractility of post-hypoxic isolated guinea pig atria - Potential implications for the treatment of ischemic-reperfusion injury.

Context Ischemic-reperfusion injury is accompanied by a decreased contractility of the myocardium. Positive-inotropic agents have proven useful for treating this condition but may exert serious side-effects. Objective In this study, aqueous preparations from Abelmoschus esculentus L. Moench (Malvaceae), Annona muricata L. (Annonaceae), Bixa orellana L. (Bixaceae), Cecropia peltata L. (Moraceae), Erythrina fusca Lour. (Fabaceae), Psidium guajava L. (Myrtaceae) and Terminalia catappa L. (Combretaceae) were evaluated for their ability to improve the decreased contractility of isolated guinea pig atria after hypoxic stress. Materials and methods Guinea pig atria isolated in Ringer-Locke buffer gassed with 100% O2 at 30 °C were exposed for 5 min to hypoxia, then allowed to recover in oxygenated buffer alone or containing a single plant extract (0.001-1 mg/mL). The contractility (g/s) and beating frequency (beats/min), as well as troponin C contents of the bathing solution (ng/mL), were determined and expressed as means ± SDs. Results The extracts of A. muricata, B. orellana, C. peltata and T. catappa caused an increase in the contractility compared to untreated atria of 340 ± 102%, 151 ± 13%, 141 ± 14% and 238 ± 44%, respectively. However, the latter two preparations increased the troponin C contents of the bathing solution to 36 ± 11 and 69 ± 33, compared to the value of 11 ± 3 ng/mL found with untreated atria. Conclusions Preparations from A. muricata and B. orellana may possess positive-inotropic properties which may improve the contractility of the post-hypoxic myocardium. Studies to assess their usefulness in ischemic-reperfusion injury are warranted.