Quality assessment and scavenging activity of Siamese neem flower extract

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

Siamese neem flower extract suppresses cholesterol absorption by interfering NPC1L1 and micellar property in vitro and in intestinal Caco-2 cells

Siamese neem (Azadirachta indica A. Juss var. siamensis Valeton) (A. indica) leaf extract, a traditional ayurvedic medicine, has been reported to exhibit antipyretic, antibacterial, antidyslipidemic, and antihyperglycemia effects. This study investigated the mechanism of hypocholesterolemic effect of methanolic extract of Siamese neem flowers in in vitro studies and in Caco-2 cells. Pancreatic cholesterol esterase and 3-hydroxy 3-methylglutaryl-CoA (HMG-CoA) reductase activities were assessed. Cholesterol micelle formation was prepared for in vitro cholesterol physicochemical property analyses, micelle size and solubility, and transport of cholesterol into the Caco-2 cells. The expression of niemann-pick C1 like 1 (NPC1L1), and its major regulator, peroxisome proliferator-activated receptor δ (PPARδ), were determined by western blot and real time polymerase chain reaction, respectively. A. indica flower extract inhibited pancreatic cholesterol esterase activity and increased cholesterol micelles size. Uptake of cholesterol into Caco-2 cells was inhibited by A. indica flower extract in a dose-dependent manner. In addition, A. indica extract inhibited HMG-CoA reductase activity, resulting in low level of intracellular cholesterol accumulation, together with increased cytosolic NPC1L1 protein expression and decreased PPARδ gene expression. In conclusion, A. indica flower extract has cholesterol-lowering effects by inhibiting intestinal cholesterol absorption, interfering micellar cholesterol formation, and attenuating cholesterol synthesis. As such, A. indica flower extract has potential for developing into nutraceutical product for prevention of hypocholesterolemia.

Effect of Azadirachta indica flower extract on functional recovery of sciatic nerve crush injury in rat models of DM

Chronic hyperglycemia causes nerves to be more susceptible to compression, which often occurs as a result of hyperglycemia-induced oxidative stress. Oxidative stress impairs nerve function and delays nerve recovery. Azadirachta indica, a herb from Thailand, possesses antioxidant and antidiabetic properties. The aim of the present study was therefore to investigate the effect of A. indica flower extract on the functional recovery of a sciatic nerve crush injury in rat models of diabetes mellitus (DM). Male Wistar rats were randomly assigned into seven groups including the control rats, rats with DM subjected to sham surgery and treated with vehicle, and rats with DM subjected to the crush surgery and treated with vehicle or A. indica flower extract at a dose of 250, 500 or 750 mg/kg animal body weight, or with vitamin C. DM was induced using a single intraperitoneal injection of streptozotocin (55 mg/kg animal body weight). Rats subjected to a sciatic nerve crush injury or sham surgery were orally treated with either vehicle, A. indica flower extract or vitamin C for 21 days. Functional recovery was assessed every 3 days using a walking track analysis, foot withdrawal reflex test and rotarod test. At the end of the study, the rats were sacrificed and their left sciatic nerves were harvested in order to determine malondialdehyde levels, superoxide dismutase activity and axon density. The treatment with A. indica flower extract significantly improved functional recovery, especially motor and sensory functions. The extract significantly decreased malondialdehyde levels, and increased superoxide dismutase activity and axon density. The results of the current study indicate that the mechanism underlying the enhanced functional recovery of the sciatic nerve following treatment with A. indica flower extract may be associated with an antioxidative effect. However, further studies are required to confirm the current results.

Characterisation of an extract and fractions of Azadirachta indica flower on cholesterol lowering property and intestinal motility

Azadirachta indica has long been used in traditional medicine. This study focused on isolation and characterisation of active ingredients in the extract, its fractions (NF-EA, NF-AQ, NF-G) and its effect on the cholesterol absorption activity. The NF-EA fraction was identified by marker compounds by LC-ESI-QTOF/MS. Cholesterol absorption activity was performed by measuring the solubility and size of cholesterol micelles. The intestinal motility was also examined by isolated rat's ileum to test the contraction. The extract and its fractions consist of flavonoids and phenolic compounds, like quercetin, kaempferol and myricetin. We found that A. indica extract and NF-EA increase cholesterol micelles size, while the extract, NF-AQ, myricetin and quercetin, reduced the solubility of cholesterol in micelles. The extract and quercetin inhibited the contraction induced by KCl up to 29 and 18%, respectively, and also decreased CaCl₂-induced contraction. This finding is in support to traditional uses of A. indica as cholesterol-lowering agents and regulator of gastrointestinal motility.

Protective Effect of Aqueous Crude Extract of Neem (Azadirachta indica) Leaves on Plasmodium berghei-Induced Renal Damage in Mice

Malaria is a major public health problem in the world because it can cause of death in patients. Malaria-associated renal injury is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. Therefore, new plant extracts to protect against renal injury induced by malaria infection are urgently needed. In this study, we investigated the protective effect of aqueous crude extract of Azadirachta indica (neem) leaves on renal injury induced by Plasmodium berghei ANKA infection in mice. ICR mice were injected intraperitoneally with 1 × 10⁷ parasitized erythrocytes of PbANKA, and neem extracts (500, 1,000, and 2,000 mg/kg) were given orally for 4 consecutive days. Plasma blood urea nitrogen (BUN) and creatinine levels were subsequently measured. Malaria-induced renal injury was evidenced as marked increases of BUN and creatinine levels. However, the oral administration of neem leaf extract to PbANKA infected mice for 4 days brought back BUN and creatinine levels to near normalcy, and the highest activity was observed at doses of 1,000 and 2,000 mg/kg. Additionally, no toxic effects were found in normal mice treated with this extract. Hence, neem leaf extract can be considered a potential candidate for protection against renal injury induced by malaria.