In Vitro Hypoglycemic and Antioxidant Activities of Some Medicinal Plants Used in Treatment of Diabetes in Southern Ecuador

Abstract

En el proceso de identificar plantas promisorias con actividades hipoglucémicas y antioxidantes, evaluamos las actividades inhibidoras de la α-glucosidasa y la α-amilasa, el contenido fenólico soluble total (TSPC), la actividad de eliminación de radicales libres (DPPH, ABTS) y la capacidad inhibidora de la autooxidación linoleica, de doce plantas utilizadas en la medicina tradicional del Ecuador: Siparuna eggersi (Monte de oso), Croton wagneri (Moshquera), Ilex guayusa (Guayusa), Baccharis genistelloides (Tres filos), Neonelsonia acuminada (Zanahoria blanca), Oreocallis grandiflora (Cucharillo), Verbena litoralis (Verbena), Justicia colorata (Insulina), Artocarpus altilis (Fruto del pan), Adiantun poiretii (Culantrillo), Costus comosus (Caña agria) y Piper crassinervium (Guabiduca). O. grandiflora se encontró superior a las otras plantas, especialmente en términos de su actividad inhibidora sobre α-glucosidasa (IC 50 = 2.8 ± 0.4 μg / mL) y α-amilasa (IC 50 = 161.5 ± 1.3 μg / mL), así como para los radicales libres (DPPH, ABTS) actividad de barrido (IC 50-DPPH = 9.9 ± 0.06 μg / mL; IC 50-TEAC = 6.6 ± 0.55 μg / mL). Por otro lado, A. altilis tuvo la mayor capacidad inhibidora de la autooxidación linoleica (IC 50-β-CLAMS = 3.1 ± 0.20 μg / mL), y O. grandiflora, nuevamente, obtuvo el valor más alto de contenido fenólico soluble total (TSPC = 185.9 ± 0.09 GAE / g extracto). Estos hallazgos sugieren que O. grandiflora podría considerarse como un agente inhibidor y antioxidante enzimático alternativo para el tratamiento de la diabetes mellitus.

Pharmacology and Phytochemistry of Ecuadorian Medicinal Plants: An Update and Perspectives

“…Regarding the radical-scavenging and antioxidant activities of the methanolic extract of the plant, the values were 98 ± 1.4 µg/mL (DPPH), 100 ± 1.0 µg/mL (TEAC), and 43 ± 0.5 µg/mL (β-CLAMS) at the concentrations of 50, 10, and 5 mg/mL, respectively. The values were comparable with those of the reference compounds α-tocopherol and Trolox [19].…”

“…Indeed, pancreatic and intestinal glucosidases are the key enzymes of dietary carbohydrate digestion, and inhibitors of these enzymes may be effective in slowing glucose absorption to suppress postprandial hyperglycemia. In this context, it is significant to mention that the extracts and phenolic or flavonoid contents of Gaiadendron punctatum [73], Muehlenbeckia tamnifolia [93], Oreocallis grandiflora [19], and Otholobium mexicanum [56], as well as trans-tiliroside (22) [53], prenyloxy eriodictyol (92), and rhamnetin (101) [96], showed enzymatic inhibitory activity that was comparable or superior to acarbose, which is a drug that is currently used in the treatment of diabetes mellitus. Therefore, these results should promote studies on determining whether these hypoglycemic products can become sources of new antidiabetic drugs.…”

“…The exudate latex of the stem bark is used to eliminate warts and to treat wounds, sores and ulcers (3R,20S)-3,20-dihydroxydammara-24-ene 3-O-palmitate ( 17), (3R,20S)-3,20-dihydroxydam-mara-24-ene 3-O-acetate (18), trans-phytol (19), vomifoliol (20), β-sitosterol (21), trans-tiliroside (22), and sparsifol (23) (Figure 4) were isolated from the plant [53].…”

“…Quercetin 3-O-β-glucuronide (81) showed an IC 50 = 3.73 ± 0.11 µg/mL in a DPPH test [94]. The plant methanolic extract also showed remarkable inhibitory activity against α-glucosidase (IC 50 = 2.8 ± 0.4 µg/mL) and α-amylase (IC 50 = 161.5 ± 1.3 µg/mL) [19]. These findings justify the traditional medicinal uses of the plant, and suggest the potential use as a source of natural antioxidant, anti-inflammatory, and hypoglycemic products, and as a food supplement [19,94].…”

“…Kaur-16-ene (85), linolenic acid (86), and α-tocopherol (87) (Figure 12) were isolated from a hexane extract; kaur-16-ene (85) (77.2%), kaur-15-ene (4.1%), phytol (19) (3.45%), (E)-nerolidol (62) (2.22%), and (5E,9E)-farnesyl acetone (1.2%) were identified as the main constituents of the EO that was steam distilled from dried plants using GC/MS and GC/FID [95].…”