Free radical scavenging, α-glucosidase inhibitory and anti-inflammatory constituents from Indian sedges, Cyperus scariosus R.Br and Cyperus rotundus L.

BACKGROUND: Cyperus scariosus R. Br and Cyperus rotundus L are widely used in ayurvedic preparation for the treatment of diabetes and other diseases. The early literature, so far, does not indicate the presence of any bioactive principle isolated from these plants. OBJECTIVE: To identify free radical scavenging, anti-diabetic and anti- inflammatory principles from these two species. MATERIALS AND METHODS: The bioassay guided fractionation and isolation of active constituents was done by chromatographic techniques. They also evaluated their anti-oxidant activity by DPPH and ABTS. The anti-diabetic activity was screened by α- glucosidase and α- amylase assays. Also, the further evaluation of in vitro anti-inflammatory activity using THP-1 monocytic cells and in vivo anti- inflammatory activity, was confirmed by carrageenan induced rat paw edema as model. RESULTS: The activity guided isolation led to isolation of twelve compounds Which are: Stigmasterol[1], ß- sitosterol[2], Lupeol[3], Gallic acid[4], Quercetin[5], ß- amyrin[6], Oleanolic acid[7], ß- amyrin acetate[8], 4- hydroxyl butyl cinnamate[9], 4- hydroxyl cinnamic acid[10], Caffeic acid,[11] and Kaempferol[12] respectively. Among the isolates, the compounds 4 and 5 displayed potent radical scavenging activity with an IC50 values of 0.43 and 0.067 ΅g/ml. The compounds 4, 5 and 10 showed significant anti-diabetic activities. while lupeol[3] showed potent IL-1 ß activity inhibition in THP-1 monocytic cells and also displayed significant (p<0.0025) in vivo anti-inflammatory activity. CONCLUSION: Inbrief, we isolated twelve compounds from both the species. Collectively, our results suggested that aromatic compounds showed good anti-oxidant and anti-diabetic activities. SUMMARY: The study investigates the free radical scavenging, α-glucosidase inhibitory and anti-inflammatory effects of constituents isolated from Indian sedges viz. C. scariosus and C. rotundus. The results indicated that phenolic compounds displayed potent fee radical scavenging activty and alpha-glucosidase inhibition activity. While terpene constituent, Lupeol[3] showed good IL-1ß activity inhibition in THP-1 monocytic cells and also displayed significant (p<0.0025) in vivo anti inflammatory activity in carrageenan induced rat paw edema. However, further studies are required to know the exact molecular mechanism. Abbreviations used: DPPH: 2,2- Diphenyl-1-1-picryl hydrazyl, ABTS: 2,2-Azinobis-3-ethylbenzo thiazoline-6-sulfonic acid, THP-1: Human leukaemia monocytic cell line, IL-1ß: Interleukin-1ß, IC50-Inhibitory concentration 50%.

Advanced glycation end-products inhibitors isolated from Schisandra grandiflora.

Free radicals scavenging and advanced glycation end-products (AGEs) inhibitory potentials in crude chloroform extract of Schisandra grandiflora were evaluated. Bioassay-guided isolation of the chloroform extract led to the identification of 24 compounds. Among the isolates, ( ± ) gomisin M1, arisantetralone C and D, macelignan, saurulignan B and SZ-MO displayed potent-free radical scavenging as well as AGEs inhibitory potentials. This is the first report identifying the presence of AGEs inhibitory activity and assigning AGEs inhibitory activity to these compounds. Therefore, our research finds new application of traditional medicinal plant S. grandiflora having capacity to reduce formation and accumulation of AGEs in diabetes.

New free radical scavenging neolignans from fruits of Piper attenuatum.

OBJECTIVE: The aim was to study and identify free radicals scavenging and antihyperglycemic principles in fruit of Piper attenuatum. MATERIALS AND METHODS: Bioassay guided identification of extracts possessing potent free radical scavenging activity, and isolation of compounds was done. Chloroform extract of P. attenuatum possessing potent radical scavenging activity was also evaluated for antihyperglycemic activity following oral glucose tolerance test in rats. RESULTS: Nine neolignans namely, denudatin B (1), iso-4', 5'-dimethoxy-3, 4-methylenedioxy-2'-oxo-Δ(3',5',8')-8.1'-lignan (2), lancifolin D (3), denudatin A (4), wallichinin (5), piperenone (6), lancifolin C (7), 2-oxo-piperol B (8), piperkadsin A (9) and a crotepoxide (10) was identified in Chloroform extract of P. attenuatum. Neolignans (1-9) displayed potent 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical and piperkadsin A (9) also displayed 1, 1-diphenyl-2-picrylhydrazyl radical scavenging activity. Analysis of structure-activity relationship revealed that presence of furan ring and methoxy groups is an important criterion to influence 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging potentials. Chloroform extract of P. attenuatum fruit could not display antihyperglycemic activity following oral glucose tolerance test in rats. CONCLUSION: Neolignans present in P. attenuatum fruits are potent free radical scavengers and this is the first report identifying these compounds and activities in this fruit.

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.

Influence of antioxidant rich fresh vegetable juices on starch induced postprandial hyperglycemia in rats.

This research analyzed the major chemical components and multiple antioxidant activities present in the fresh juice of eight vegetables, and studied their influence on starch induced postprandial glycemia in rats. A SDS-PAGE based protein fingerprint of each vegetable juice was also prepared. The yields of juice, chemical components like total proteins, total polyphenols, total flavonoids, total anthocyanins and free radicals like the ABTS˙(+) cation, DPPH, H(2)O(2), scavenging activities and reducing properties for NBT and FeCl(3) showed wide variations. Vegetable juice from brinjal ranked first in displaying total antioxidant capacity. Pretreatment of rats with vegetable juices moderated starch induced postprandial glycemia. The fresh juice from the vegetables ridge gourd, bottle gourd, ash gourd and chayote significantly mitigated postprandial hyperglycemic excursion. Total polyphenol concentrations present in vegetable juices positively influenced ABTS˙(+) scavenging activity and total antioxidant capacity. However, NBT reducing activity of juices was positively affected by total protein concentration. Contrarily, however, high polyphenol content in vegetable juice was observed to adversely affect the postprandial antihyperglycemic activity of vegetable juices. This is the first report exploring antihyperglycemic activity in these vegetable juices and highlights the possible adverse influence of high polyphenol content on the antihyperglycemic activity of the vegetable juices.