Insulin secreting and α-glucosidase inhibitory activity of hexane extract of Annona squamosa Linn. in streptozotocin (STZ) induced diabetic rats.

The hexane extract of A. squamosa (ASHE) in 100 and 400 mg/kg body weight dose raised the insulin level when compared with Glimepiride (1 mg/kg) and also inhibited α-glucosidase activity when compared with Acarbose (10 mg/kg) in streptozotocin induced diabetic rats. The ASHE significantly reduced peak blood glucose (Gp30) and area under curve (AUC) in diabetic rats in oral glucose (OGTT) and oral sucrose (OSTT) tolerance test, but there was more reduction of Gp30 value than AUC in OSTT. Thus, it can be suggested that the ASHE, has hypoglycemic role at 2 levels, i.e. it acts as secretagogue and also inhibits the intestinal enzymes, responsible for glucose metabolism.

Effect of Nigella sativa seeds extracts on iNOS through antioxidant potential only: Crude/total extract as molecular therapy drug.

There is general belief that only pure phytomolecules may be used as molecular therapeutic agent through one to one action. However, the traditional systems of medicine e.g. Ayurveda, uses the crude extracts, mostly water decoctions and oils, as drug. A comparative study of hexane, ethyl acetate and methanol fractions of N. Sativa seeds has been carried out on fresh rat-peritoneal-macrophage culture with reference to their role on various targets of lipopolysaccharide induced release of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) expression. The results indicated significant antioxidant potential with methanolic extract as most effective. Its mechanism of action was proposed primarily through its antioxidant potential and not through direct inhibition of other kinases, involved in its signaling cascade.

Oily fraction of Semecarpus anacardium Linn nuts involves protein kinase C activation for its pro-inflammatory response.

The oily fraction (non polar fraction-NPF) of S. anacardium (SA) significantly increased the expression of protein kinase C-δ (PKC-δ) in macrophages in concentration dependent manner, which was similar to phorbol myristate acetate (PMA) response. Further, H-7 (1-(5-isoquinolinesulphonyl)-2-methylpiperazine), an inhibitor of PKC significantly inhibited this NPF mediated response in a concentration dependent manner. In the post treatment kinetics, H-7 showed this inhibition only up to 6 min post NPF/PMA addition, but in similar condition, quercetin, a flavone with reported antioxidant property, showed this inhibition only up to 2 min. The results clearly suggest that oily fraction of SA nuts enhances the expression of PKC protein, which may be responsible for its reported pro-inflammatory property.

Extract of gum resins of Boswellia serrata L. inhibits lipopolysaccharide induced nitric oxide production in rat macrophages along with hypolipidemic property.

Boswellia serrata, Linn F (Burseraceae) is commonly used in Indian system of medicine (Ayurvedic) as an anti-inflammatory, analgesic, anti-arthritic and anti-proliferative agent. This study was planned to investigate the water-soluble fraction of the oleoresin gum of Boswellia serrata (BS extract) on lipopolysaccharide (LPS) induced nitric oxide (NO) production by macrophages under in vivo and in vitro conditions. In the previous condition, rats were fed on atherogenic diet (2.5% cholesterol, 1% cholic acid, 15.7 % saturated fat) along with the BS extract for 90 days. Blood was collected for lipid profile and toxicological safety parameters. Peritoneal macrophages were isolated and cultured to see the LPS induced NO production. Under in vivo experiment, BS extract significantly reduced serum total cholesterol (38-48 %), increased serum high-density lipoprotein- cholesterol (HDL-cholesterol, 22-30%). Under in vitro experiments with thioglycolate activated macrophages, it inhibited LPS induced (NO) production with IC 50 value at 662 ng /ml. Further, this fraction, in the dose of 15 mg/100 g body wt for 90 days, did not show any increase in serum glutamate-pyruvate transaminase (SGPT) and blood urea, in normal control animals. However, it significantly reversed the raised SGPT and blood urea in the atherogenic diet-fed animals. Transverse section of liver and kidney also supported its protective effect. Thus it may be concluded that water extract of Boswellia serrata possesses strong hypocholesterolemic property along with increase in serum HDL. It inhibits the LPS induced NO production by the activated rat peritoneal macrophages and show hepato-protective and reno-protective property.