Effects of berberine on cholinesterases and monoamine oxidase activities, and antioxidant status in the brain of streptozotocin (STZ)-induced diabetic rats.

OBJECTIVES: Several studies had been conducted to examine the link between diabetes and diabetes encephalopathy. This study was conducted to examine the potency of berberine (BER) on the restoration of impaired neurochemicals in the brain of streptozotocin (STZ)-induced diabetic Wistar rats. METHODS: Fifty-six (56) adult rats weighing between 200 and 230 g were randomly divided into seven groups (n=8) as follows; Group I is normal control; Groups II and III were normal rats treated with 50 and 100 mg/kg respectively; Group IV-VII were STZ-induced rats, but Groups V-VII were treated with acarbose (25 mg/kg), 50 and 100 mg/kg of BER, respectively. RESULTS: The result of the study showed that untreated STZ-induced diabetic rats have increased acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO) activities, and malonylaldehyde (MDA) level, with concomitant decrease of superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, and glutathione (GSH) level. However, daily treatment with 50 and 100 mg/kg BER and ACA significantly reversed these effects. CONCLUSIONS: The findings of this study clearly indicated that BER possesses neuro-protective and antioxidative potentials and normalize neurochemical impairment distort by diabetes.

Modulatory effect of quercetin and its glycosylated form on key enzymes and antioxidant status in rats penile tissue of paroxetine-induced erectile dysfunction.

This study sought to compare the effects of quercetin and rutin on some enzymes linked to erectile function as well as antioxidant status in penile tissue of paroxetine - induced erectile dysfunction in rats. Animals were randomly divided into twelve groups: normal control (NC), sildenafil (SD), quercetin (QA) (25 and 50 mg/kg), rutin (RU) (25 and 50 mg/kg), PAR (10 mg/kg); PAR + SD; PAR + QA, PAR + RU (25 and 50 mg/kg). After 14 days' treatment, phosphodiesterase-5' (PDE-5'), arginase, adenosine deaminase (ADA), acetylcholinesterase (AChE) and angiotensin-I converting enzyme (ACE) activities as well as malondialdehyde (MDA) and non-protein thiol levels were determined in rat penile tissues. Elevated levels of PDE-5', arginase, AChE, ADA and ACE activities and MDA were observed in PAR-induced rats with concomitant decrease in non-protein thiol levels when compared to the NC group. However, treatment with SD, QA and RU significantly reduced the activities of AChE, PDE-5', arginase, ADA and ACE and MDA levels and elevated non-protein thiol levels in penile tissues of PAR-induced rats. Furthermore, administration of QA and RU in PAR-induced rats modulated the key enzymes relevant to erection, improved antioxidant status and could be potential functional food ingredients and nutraceuticals in the prevention and/or management of erectile dysfunction.

Phenolic constituents and modulatory effects of Raffia palm leaf (Raphia hookeri) extract on carbohydrate hydrolyzing enzymes linked to type-2 diabetes.

This study sought to investigate the effects of Raffia palm (Raphia hookeri) leaf extract on enzymes linked to type-2 diabetes mellitus (T2DM) and pro-oxidant induced oxidative stress in rat pancreas. The extract was prepared and its α-amylase and α-glucosidase inhibitory effects were determined. Radical [2,2-diphenyl-1-picrylhydrazyl (DPPH)] scavenging and Fe2+-chelating abilities, and inhibition of Fe2+-induced lipid peroxidation in rat pancreas homogenate were assessed. Furthermore, total phenol and flavonoid contents, reducing property, and high performance liquid chromatography diode array detector (HPLC-DAD) fingerprint of the extract were also determined. Our results revealed that the extract inhibited α-amylase (IC50 = 110.4 µg/mL) and α-glucosidase (IC50 = 99.96 µg/mL) activities in concentration dependent manners which were lower to the effect of acarbose (amylase: IC50 = 18.30 µg/mL; glucosidase: IC50 = 20.31 µg/mL). The extract also scavenged DPPH radical, chelated Fe2+ and inhibited Fe2+-induced lipid peroxidation in rat pancreas all in concentration dependent manners with IC50 values of 402.9 µg/mL, 108.9 µg/mL and 367.0 µg/mL respectively. The total phenol and flavonoid contents were 39.73 mg GAE/g and 21.88 mg QAE/g respectively, while the reducing property was 25.62 mg AAE/g. The HPLC analysis revealed the presence of chlorogenic acid (4.17 mg/g) and rutin (5.11 mg/g) as the major phenolic compounds in the extract. Therefore, the ability of the extract to inhibit carbohydrate hydrolyzing enzymes and protect against pancreatic oxidative damage may be an important mechanisms supporting its antidiabetic properties and could make Raffia palm leaf useful in complementary/alternative therapy for management of T2DM. However, further studies such as in vivo should be carried out.