Amtul Zehra

Synthesis and antiglycation potentials of bergenin derivatives

Bergenin (1), major bioactive compound isolated from methanolic extract of Mallotus philippinensis, displayed moderate AGE inhibition activity (IC(50)=186.73 μM). A series of derivatives of bergenin (3a-k) containing variety of aromatic acids were synthesized under mild conditions by modification of sugar part. Selective esterification of hydroxyl groups on the sugar part enhanced antiglycation potential of bergenin. Compounds 3j and 3k exhibited potent antiglycation activity with the IC(50) values of 60.75 and 12.28 μM, respectively.

Mitigation of starch and glucose-induced postprandial glycemic excursion in rats by antioxidant-rich green-leafy vegetables' juice.

Objective: Consumption of green-leafy vegetables is being advocated beneficial for type 2 diabetes mellitus individuals possibly because they are cost effective source of potent biological antioxidants. This research analyzed various phytochemicals, free radicals scavenging antioxidant potentials and starch digesting enzymes inhibitory activities in fresh juice of nine green-leafy vegetables. Furthermore, this study also investigated influence of these vegetables juice on starch and glucose induced postprandial glycemic load. Materials and Methods: Phytochemical constituents, in vitro free radicals scavenging antioxidant and enzymes inhibitory activities were evaluated applying various reported methods. Post-prandial glycemic excursion was induced in rats pretreated with vegetables juice by oral administration of starch and glucose. Results: All the leafy vegetables juice displayed potent free radicals scavenging activities. Juice of amaranthus, rumex, palak and raphanus displayed potential anti-oxidative property by reducing H2O2 induced hemolysis in rats red blood cells RBCs. Ajwain and rumex juice showed pancreatic α-amylase inhibitory activity. Alternanthera, ajwain, methi, amaranthus and sowa leaves juice displayed intestinal α-glucosidase inhibitory activity. Juice of raphanus, ajwain and sowa significantly mitigated starch-induced postprandial glycemic load. Amaranthus leaves juice potently mitigated glucose-induced postprandial glycemic load and also reduced hemoglobin glycation induced by glucose in vitro. Conclusions: This investigation finds that juice of leafy vegetables is potent source of biological antioxidants. In addition, juice of raphanus, ajwain and sowa leaves possess capacity to mitigate starch induced postprandial glycemic burden and amaranthus leaves’ juice can reduce glucose induced postprandial glycemic excursion.

Vegetables' juice influences polyol pathway by multiple mechanisms in favour of reducing development of oxidative stress and resultant diabetic complications

Objective: Hyperglycemia induced generation of free radicals and consequent development of oxidative stress by polyol pathway is one of the crucial mechanisms stirring up development of diabetic complications. We evaluated influence of ten vegetables’ juice on polyol pathway along with their antioxidant and antioxidative stress potentials. Materials and Methods: Aldose reductase activity was determined utilising goat lens and human erythrocytes. In goat lens, utilization of nicotinamine adenine dinucleotide phosphate (NADPH) and aldose reductase inhibition was assayed. In human erythrocytes, sorbitol formation was measured as an index of aldose reductase activity under normoglycemic and hyperglycemic conditions. Ability of juices in inhibiting oxidative damage to deoxyribose sugar and calf thymus DNA and inhibitory activity against hydrogen peroxide induced hemolysis of erythrocytes was also analysed. Phytochemical contents like total polyphenol, total flavonoid and total protein were measured to find their influence on biological activities. Results: Vegetables’ juice displayed varying degrees of inhibitory potentials in mitigating NADPH dependent catalytic activity of aldose reductase in goat lens, accumulation of sorbitol in human erythrocytes under different glucose concentrations; Fenton-reaction induced oxidative damage to deoxyribose sugar, and calf thymus DNA. Substantial variations in vegetables phytochemicals content were also noticed in this study. Conclusions: Vegetables’ juice possesses potent activities in influencing polyol pathway by various mechanisms in favour of reducing development of oxidative stress independent of their inherent antioxidative properties. Juice of ivy gourd followed by green cucumber and ridge gourd were among the most potent for they displayed strong activities on various parameters analysed in this study. These vegetables’ juice may become part of mechanism-based complementary antioxidant therapy to prevent development of diabetic complications.

Presence of postprandial antidysmetabolic and antioxidative stress properties in aqueous methanol extract of seeds and tuber of aquatic food plant Nymphaea nouchali (Burm.f.)

Abstract Aqueous methanol extract of seeds and tuber of food and medicinal plant Nymphaea nouchali (Burm.f.) displayed potent pancreatic lipase and intestinal α-glucosidase inhibitory properties. These properties may help reduce development of diet induced postprandial hyperlipidaemia and postprandial hyperglycaemia respectively. In addition, seeds and tuber extracts possess potent free radicals scavenging activities and reducing power. Furthermore, extracts also displayed strong inhibitory activities against formation of various advanced glycation end-products which is an important link inducing postprandial oxidative stress due to postprandial hyperlipidaemia and postprandial hyperglycaemia. Seeds and tubers of N. nouchali are rich sources of polyphenolic and flavonoids. Results of this study show for the first time that N. nouchali seeds and tuber may become an important dietary supplement to counter development of diet induced hyperglycaemia, hyperlipidaemia and resultant oxidative stress and can be utilized as herbal therapeutics for management of type 2 diabetes mellitus and obesity.

Highly selective one pot synthesis and biological evaluation of novel 3-(allyloxy)-propylidene acetals of some natural terpenoids

A series of 3-(allyloxy)-propylidene acetals 1a to 6a of some natural terpenoids like andrographolides 1, 2, forskolins 3–5 and arjunolic acid 6 were developed by a novel one pot synthetic strategy using ceric ammonium nitrate as a catalyst. The method is both chemo and regioselective towards 1,3-acetal formation without affecting other poly functional groups of terpenoids. O-Allylation is an important functional group transformation for alcohols and the resulting end allylic double bond may participate in a number of synthetically useful transformations like olefin metathesis. Acetal of andrographolide 1a was further converted into 1b, 1c and 1d by dimerization, acetylation and epoxidation respectively. All the synthesized compounds were screened for in vitro antiproliferative activity against four cancer cell lines B16F10, THP-1, PC-3 and SKOV3. Derivatives of andrographolide 1a, 1b, 1c and 2a, forskolin 4a and arjunolic acid 6a have shown promising cytotoxicity (IC50 < 10 μg ml−1) in most of the tested cell lines. Also compounds 1b (IC50 0.83 μg ml−1) and 5a (IC50 3.43 μg ml−1) showed significant α-glucosidase inhibition in an in vitro assay. Structures of all the synthesized compounds were confirmed by NMR, mass and IR spectral data. A single crystal X-ray analysis of 5a also confirmed the 3-(allyloxy)-propylidene acetal formation.