Helianthus annuus Leaf Ameliorates Postprandial Hyperglycaemia by Inhibiting Carbohydrate Hydrolyzing Enzymes Associated with Type-2 Diabetes

In vitro antioxidant and enzyme inhibitory properties of the n-butanol fraction of Senna podocarpa (Guill. and Perr.) leaf

Background This study evaluates the antioxidant activity and enzyme inhibitory properties of the n-butanol fraction of Senna podocarpa leaves on α-amylase, α-glucosidase, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, arginase, phosphodiesterase 5 (PDE-5), and angiotensin converting enzyme (ACE). Methods The total phenol and flavonoids, iron (Fe) chelation, and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical scavenging were used to determine the antioxidant activity, and the inhibitory activities of α-glucosidase, α-amylase, AChE, BChE, tyrosinase, arginase, PDE-5 and ACE were also assessed. Results The n-butanol fraction of S. podocarpa shows high total phenol and total flavonoid contents. The n-butanol fraction of S. podocarpa leaves also chelates Fe2+ and ABTS radicals. The n-butanol fraction of S. podocarpa leaves also inhibited α-glucosidase, α-amylase, AChE, BChE, tyrosinase, arginase, PDE-5, and ACE at the concentration tested. Chromatographic analysis displayed the presence of β-elemene, phytol and caryophyllene oxide chrysophanol, 3-oxo-methyl ester, α-humulene, β-caryophyllene, rhein, emodin, and α-copaene. Conclusions Hence, the n-butanol fraction of S. podocarpa leaves demonstrates encouraging feat in controlling and/or managing cognitive dysfunction such as Alzheimer's disease and also hypertension, diabetes, erectile dysfunction, endothelial dysfunction, and hyperpigmentation.

Inhibitory Effects of Solvent-Partitioned Fractions of Two Nigerian Herbs (Spondias mombin Linn. and Mangifera indica L.) on α-Amylase and α-Glucosidase

Therapies directed towards controlling hyperglycemia, the hallmark of type-2 diabetes mellitus, go a long way in managing diabetes and its related complications. Reducing glucose level through the inhibition of the relevant carbohydrate hydrolyzing enzymes is one among many routes in the management of diabetes. This study investigates the in vitro enzyme inhibitory and antioxidant properties of solvent-partitioned fractions of Spondias mombin and Mangifera indica leaves; which are used extensively in the treatment of diabetic patients locally. The leaves of S. mombin and M. indica were extracted with methanol and fractionated to obtain n-hexane (HF), ethyl acetate (EAF), n-butanol (BF), and aqueous (AF) fractions successively. The α-amylase and α-glucosidase inhibitory activities of fractions of S. mombin and M. indica leaves were investigated while the antioxidant activity of each fraction was analyzed using iron chelating and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid) radical scavenging assay. Our findings indicated that the ethyl acetate fraction of M. indica leaves contained a considerably higher (p < 0.05) amount of total phenolic, flavonoids, metal ion, and ABTS radical scavenging activity than the ethyl acetate fractions of S. mombin. Furthermore, the ethyl acetate fraction of M. indica had a considerably higher (p < 0.05) inhibitory effect on α-glucosidase (IC₅₀ = 25.11 ± 0.01 μg mL^-1), and α-amylase (IC₅₀ = 24.04 ± 0.12 μg mL^-1) activities than the S. mombin fraction. Hence, the inhibitory activities of S. mombin and M. indica leaves suggest that they are a potential source of orally active antidiabetic agents and could be employed to formulate new plant-based pharmaceutical and nutraceutical drugs to improve human health.

Inhibitory effect of aqueous extracts of raw and roasted Sesamum indicum L. seeds on key enzymes linked to type-2 diabetes (α-amylase and α-glucosidase) and Alzheimer's disease (acetylcholinesterase and butyrylcholinesterase)

Sesame (Sesamum indicum L.) seeds are nutritional food, but researches have limited knowledge about the antioxidant, antidiabetic and anticholinesterase activities of the seed. This study was conducted to determine the antioxidant activity, enzyme inhibitory potential (α-amylase and α-glucosidase) and acetylcholinesterase inhibitory property of aqueous extracts of raw and roasted sesame seeds. Antioxidant activities were analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging property, 2,2-azino-bis-(3-ethylbenthiazoline-6- sulphonic acid (ABTS) scavenging ability, iron chelating ability and ferric reducing antioxidant power (FRAP). Anti-Alzheimer's potential was determined using acetylcholinesterase and butyrylcholinesterase enzyme inhibition assay. The results showed that the total phenolic and flavonoid contents were higher in the roasted S. indicum sample with the values of 19.81mg/100g and 17.19 mg/100g respectively. The raw S. indicum sample showed higher antioxidant activity in DPPH, and iron chelation assays; while roasted S. indicum sample showed higher in the reducing power and ABTS scavenging activity. However, anticholinesterase activity was higher in the roasted S. indicum sample than in the raw S. indicum sample. The extracts inhibited α-amylase activity in a concentration-dependent manner (20 - 100 µg.mL-1). The raw sample (16.55 ±0.89%) had higher inhibitory α-amylase activity compared to the roasted sample (15.78 ±0.48%) at 100 µg.mL-1. Inhibition of α-glucosidase was higher in the roasted sample at 100 µg.mL-1 (19.40 ±0.26%) compared to the raw sample at the same concentration (3.65 ±0.52%). These findings suggest that S. indicum L. is not only nutritious but also showed potential pharmacological properties.