Potentiation of paraquat toxicity by inhibition of the antioxidant defenses and protective effect of the natural antioxidant, 4-hydroxyisopthalic acid in Drosophila melanogaster.

Exposure to pesticides such as paraquat (PQ) is known to induce oxidative stress-mediated damage, which is implicated in neurodegenerative diseases. The antioxidant enzymes are part of the endogenous defense mechanisms capable of protecting against oxidative damage, and down-regulation of these enzymes results in elevated oxidative stress. In this study, we have evaluated the protective action of 4-hydroxyisophthalic acid (DHA-I), a novel bioactive molecule from the roots of D. hamiltonii, against PQ toxicity and demonstrated the protective role of endogenous antioxidant enzymes under the condition of oxidative stress using Drosophila model. The activity of the major antioxidant enzymes, superoxide dismutase 1 (SOD1) and catalase, was suppressed either by RNAi-mediated post transcriptional gene silencing or chemical inhibition. With the decreased in vivo activity of either SOD1 or catalase, Drosophila exhibited hypersensitivity to PQ toxicity, demonstrating the essential role of antioxidant enzymes in the mechanism of defense against PQ-induced oxidative stress. Dietary supplementation of DHA-I increased the resistance of Drosophila depleted in either SOD1 or catalase to PQ toxicity. Enhanced survival of flies against PQ toxicity indicates the protective role of DHA-I against oxidative stress-mediated damage under the condition of compromised antioxidant defenses.

Natural bioactive 4-Hydroxyisophthalic acid (4-HIPA) exhibited antiproliferative potential by upregulating apoptotic markers in in vitro and in vivo cancer models.

There is tremendous scope for identifying novel anti-cancer molecules from the unexplored reserves of plant kingdom. The application of dietary supplementation or medicine derived from such sources is a promising approach towards treatment of cancer. In the present study we have evaluated the antiproliferative potential of 4-hydroxyisophthalic acid (4-HIPA), which is a novel antioxidant compound isolated from the roots of the aqueous extract of Decalepis hamiltonii. 4-HIPA was screened in vitro against human breast cancer cell lines MCF-7, MDA-MB-468 and normal human breast epithelial cell MCF-10, and demonstrated that human breast cancer cell lines, in contrast to MCF-10, are sensitive to 4-HIPA .4-HIPA showed marked reduction in cell viability and short-term proliferation assays in these cells. Results of the long-term colony formation and scratch assay further reaffirmed that 4-HIPA inhibited the growth and proliferation in breast cancer cells. We further conducted in vivo studies using murine Ehrlich Ascites Tumor (EAT) cell model. Our in vivo results established that treatment with 4-HIPA reduced the tumorigenesis by promoting apoptosis in EAT-bearing mice. The results of our molecular docking predictions further warranted our claim. This study is valuable as 4-HIPA exhibits antiproliferative potential that can be exploited in the development of anticancer drugs.

4-Hydroxyisophthalic acid from Decalepis hamiltonii rescues the neurobehavioral deficit in transgenic Drosophila model of taupathies.

Oxidative stress is one of the major etiological factors implicated in pathogenesis of neurodegenerative diseases. Since neurons are more sensitive to oxidative damage there is an increasing interest in developing novel antioxidant therapies, especially herbal preparations due to their safety profile and high efficiency. In this regard, the neuroprotective potential of a novel antioxidant compound, 4-hydroxyisophthalic acid (4-HIPA) isolated from aqueous extract of Decalepis hamiltonii roots was examined using transgenic Drosophila model of taupathy expressing wild-type and mutant forms of 2N4R isoform of human microtubule associated protein tau (MAPT). Taupathy model flies showed cognitive deficits in olfactory memory and deteriorated circadian rhythm of locomotory activities. Administration of 0.1 mg/ml 4-HIPA, markedly enhanced their olfactory memory performance and restored circadian rhythmicity of the transgenic flies locomotory behavior to the normal range. The mechanism of action that underlies 4-HIPA neuroprotection involves enhancement in efficiency of cellular antioxidant defense system by means of elevation in antioxidant enzyme activities and attenuation of oxidative stress. The molecule could positively affect the activity of neurotransmitter enzymes, which in turn enhances neuronal function and ameliorates the Tau-induced neurobehavioral deficits. Our findings showed that 4-HIPA can be considered as a suitable therapeutic candidate for drug development towards treatment of neurodegenerative disorders.

Neuroprotective effect of Decalepis hamiltonii on cyclophosphamide-induced oxidative stress in the mouse brain.

BACKGROUND: Cyclophosphamide (CP), one of the most widely used antineoplastic drugs, causes toxic side effects on vital organs including brain. In this study, we have investigated neuroprotective potential of the aqueous extract of the roots of Decalepis hamiltonii (DHA) against CP-induced oxidative stress in the mouse brain. METHODS: Swiss albino male mice were pre-treated with DHA (50 and 100 mg/kg b.w.) for 10 consecutive days followed by an injection with CP intraperitoneally (25 mg/kg b.w.) for 10 days 1 h after DHA treatment; 16 h later, they were euthanized, their brains were immediately removed, and biochemical and molecular analyses were conducted. RESULTS: The results indicated that injection of CP induced oxidative stress in the mouse brain as evident from the increased lipid peroxidation, reactive oxygen species, depletion of glutathione and reduced activities of the antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase. Treatment with DHA significantly mitigated the CP-induced oxidative stress. Moreover, expression of genes for the antioxidant enzymes was downregulated by CP treatment which was reversed by DHA. CONCLUSIONS: In conclusion, DHA protected the brain from oxidative stress induced by CP, and therefore, it could be a promising nutraceutical as a supplement in cancer chemotherapy in order to ameliorate the toxic side effects of cancer drugs.

Attenuation of neuromotor deficits by natural antioxidants of Decalepis hamiltonii in transgenic Drosophila model of Parkinson's disease.

Oxidative stress is believed to be a major factor for the onset of Parkinson's disease (PD). In this study, we have investigated oxidative status in transgenic Drosophila model of PD. Our results revealed elevated levels of reactive oxygen species (ROS) and lipid peroxidation (LPO) in A30P and A53T α-synuclein PD model flies compared to control. We have demonstrated for the first time the ameliorating potential of natural antioxidants characterized from the roots of Dh in A30P and A53T α-synuclein PD model flies. Feeding of transgenic flies with aqueous Dh root extract for 21 days significantly improved their climbing ability and circadian rhythm of locomotor activity which was associated with reduction in levels of ROS and LPO and enhancement in the activities of catalase (CAT) and superoxide dismutase (SOD). Dh protected against paraquat (PQ) sensitivity in α-synuclein transgenic flies and delayed the onset of PD-like symptoms which appears to be mediated by suppression of oxidative stress.

Modulatory effect of Decalepis hamiltonii on ethanol-induced toxicity in transgenic Drosophila model of Parkinson's disease.

Overexpression of human α-synuclein gene in Drosophila can reduce lifespan, and we have performed lifespan assay for A30P and A53Tα-synuclein transgenic and control (elav-GAL4, UAS-A30P, UAS-A53T) flies. Our results showed reduced lifespan of transgenic flies compared to controls. We have also investigated behavioral responses, levels of reactive oxygen species (ROS) and lipid peroxidation (LPO) and activities of catalase (CAT) and superoxide dismutase (SOD) in a combined genetic-toxin model (Ethanol-A30P or A53Tα-synuclein models) and controls. Our results showed that sedation time (ST50) of A30P or A53Tα-synuclein PD model flies was significantly lower while recovery time (RC50) of them was remarkably higher compared to control flies. The levels of oxidative markers (ROS and LPO) were significantly higher and the activities of CAT and SOD were lower in transgenic flies that underwent ethanol exposure compared to control. Based on our earlier studies on antioxidant properties of isolated and characterized molecules from Decalepis hamiltonii (Dh) root extract, its protective effect in this combined toxicity model has been investigated. Surprisingly, Dh treatment increased ST50 and decreased RC50 values of transgenic flies. Moreover, we showed that Dh pre-treatment could decrease the levels of ROS and LPO and increase the activities of CAT and SOD in the ethanol-α-synuclein model. This is the first report on protective effects of natural antioxidants in A30P or A53Tα-synuclein PD model flies against oxidative stress induced by ethanol.

Prevention of hexachlorocyclohexane-induced neuronal oxidative stress by natural antioxidants.

OBJECTIVE: Decalepis hamiltonii roots are traditionally consumed as general vitalizer and used in ayurvedic medicine preparations. We have isolated/characterized potent antioxidants from the aqueous extract of the root of this plant. In this study, we examined the antioxidant potential of the aqueous extract of the roots of D. hamiltonii (DHAE) against hexachlorocyclohexane (HCH)-induced oxidative stress in four major regions of the rat brain. METHODS: The antioxidant activity of the standardized DHAE with known antioxidant constituents was tested against HCH-induced oxidative stress in the major brain regions of 60-day-old adult male Wistar rats. RESULTS: Pretreatment of rats with multiple doses of DHAE, 50 and 100 mg/kg body weight (b.w.), for 7 consecutive days significantly prevented the HCH-induced (single dose -500 mg/kg b.w.) increase in lipid peroxidation, reduction in glutathione, and altered antioxidant enzyme activities viz. superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase in major rat brain regions viz. cortex, cerebellum, midbrain, and brain stem. DHAE, per se, elevated the antioxidant status of the rat brain. DISCUSSION: DHAE shows protective action against HCH-induced oxidative stress in rat brain regions. The protective effect of DHAE could be ascribed to the isolated/characterized antioxidant compounds which could be prospective novel nutraceuticals.

Neuroprotective effect of Decalepis hamiltonii in paraquat-induced neurotoxicity in Drosophila melanogaster: biochemical and behavioral evidences.

In this paper, we have demonstrated for the first time, the antioxidant and neuroprotective effects of Decalepis hamiltonii (Dh) root extract against paraquat (PQ)-induced oxidative stress and neurotoxicity in Drosophila melanogaster. Exposure of adult D. melanogaster (Oregon K) to PQ induced oxidative stress as evidenced by glutathione depletion, lipid peroxidation and enhanced activities of antioxidant enzymes such as catalase, superoxide dismutase as well as elevated levels of acetylcholine esterase. Pretreatment of flies by feeding with Dh extract (0.1, 0.5 %) for 14 days boosted the activities of antioxidant enzymes and prevented the PQ-induced oxidative stress. Dietary feeding of Dh extract prior to PQ exposure showed a lower incidence of mortality and enhanced motor activities of flies in a negative geotaxis assay; both suggesting the neuroprotective potential of Dh. Based on the results, we contemplate that the roots of Dh might prevent and ameliorate the human diseases caused by oxidative stress. The neuroprotective action of Dh can be attributed to the antioxidant constituents while the precise mechanism of its action needs further investigations.

Amelioration of cyclophosphamide-induced hepatotoxicity by the root extract of Decalepis hamiltonii in mice.

Hepatoprotective potential of the aqueous extract of the roots of Decalepis hamiltonii (DHA) against cyclophosphamide (CP)-induced oxidative stress has been investigated in mice. Administration of CP (25mg/kg b.w., i.p) for 10 days induced hepatic damage as indicated by the serum marker enzymes aspartate and alanine transaminases (AST, ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). Parallel to these changes CP induced oxidative stress in the liver as evident from the increased lipid peroxidation (LPO), reactive oxygen species (ROS), depletion of glutathione (GSH), and reduced activities of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST). Treatment with DHA (50 and 100 mg/kg b.w., po) mitigated the CP-induced oxidative stress. Moreover, expression of genes for the antioxidant enzymes, were down-regulated by CP treatment which was reversed by DHA. Our study shows the DHA protected the liver from toxicity induced by CP and therefore, it could be serve as a safe medicinal supplement during cyclophosphamide chemotherapy.

Decalepis hamiltonii root extract attenuates the age-related decline in the cognitive function in Drosophila melanogaster.

Age-associated accumulation of oxidative damage linked to decline of antioxidant defense mechanism, leads to impairment of cognitive function in many organisms. These damages can pass through generations and affect the cognitive quality of progenies. In Drosophila, classical olfactory conditioning results in the formation of different types of memory. Age-related memory impairment (AMI) causes reduction in middle term memory (MTM) and parental senescence causes decline in short-term memory (STM) of the offspring. We have further examined the neuromodulatory effect of Decalepis hamiltonii (Dh) root extract, which is a cocktail of novel antioxidant molecules, on the biochemical oxidative defenses in relation to cognitive ability of the aged flies and their offspring. There is a strong correlation between the age-related decline in the activity of the antioxidant enzymes and the lower cognitive ability of the aged flies and their offspring. Feeding of aged flies in the diet containing 0.1% Dh, markedly enhances the cognitive ability of both aged flies and their offspring which is associated with enhanced antioxidant defenses as evident for the activity of superoxide dismutase (SOD) and catalase. Our findings, for the first time, show that the antioxidant-rich Dh root extract attenuates the age-related decline in cognitive ability of Drosophila, and also shows ameliorative effect on the memory of the offspring.

2,4,8-trihydroxybicyclo [3.2.1]octan-3-one scavenges free radicals and protects against xenobiotic-induced cytotoxicity.

Currently, there is a great deal of interest in the study of natural compounds with free-radical-scavenging activity because of their potential role in maintaining human health and preventing diseases. In this paper, we report the antioxidant and cytoprotective properties of 2,4,8-trihydroxybicyclo [3.2.1]octan-3-one (TBO) isolated from the aqueous extract of Decalepis hamiltonii roots. Our results show that TBO is a potent scavenger of superoxide (O(2)·-), hydroxyl (·OH), nitric oxide (·NO) and lipid peroxide (LOO·) - physiologically relevant free radicals with IC(50) values in nmolar (42-281) range. TBO also exhibited concentration-dependent secondary antioxidant activities such as reducing power, metal-chelating activity and inhibition of protein carbonylation. Further, TBO at nmolar concentration prevented CuSO(4)-induced human LDL oxidation. Apart from the in vitro free-radical-scavenging activity, TBO demonstrated cytoprotective activity in primary hepatocytes and Ehrlich ascites tumour (EAT) cells against oxidative-stress-inducing xenobiotics. The mechanism of cytoprotective action involved maintaining the intracellular glutathione (GSH), scavenging of reactive oxygen species (ROS) and inhibiting lipid peroxidation (LPO). Based on the results, it is suggested that TBO is a novel bioactive molecule with implications in both prevention and amelioration of diseases involving oxidative stress as well as in the general well-being.

14-aminotetradecanoic acid exhibits antioxidant activity and ameliorates xenobiotics-induced cytotoxicity.

Natural compounds with free-radical scavenging activity have potential role in maintaining human health and preventing diseases. In this study, we report the antioxidant and cytoprotective properties of 14-aminotetradecanoic acid (ATDA) isolated from the Decalepis hamiltonii roots. ATDA is a potent scavenger of superoxide (O(2) (•-)), hydroxyl ((•)OH), nitric oxide ((•)NO), and lipid peroxide (LOO(•)) physiologically relevant free radicals with IC(50) values in nM (36-323) range. ATDA also exhibits concentration-dependent secondary antioxidant activities like reducing power, metal-chelating activity, and inhibition of protein carbonylation. Further, ATDA at nM concentration prevented CuSO(4)-induced human LDL oxidation. ATDA demonstrated cytoprotective activity in primary hepatocytes and Ehrlich ascites tumor cells against oxidative stress inducing xenobiotics apart from the in vitro free-radical scavenging activity. The mechanism of cytoprotective action involved maintaining the intracellular glutathione, scavenging of reactive oxygen species, and inhibition of lipid peroxidation. It is suggested that ATDA is a novel bioactive molecule with potential health implications.

Differential cholinesterase inhibition in the rat brain regions by dichlorvos and protective effect of Decalepis hamiltonii roots.

Dichlorvos (DDVP) causes neurotoxicity primarily by inhibiting cholinesterase (ChE) which is the characteristic feature of organophosphate pesticides. In this study, we found for the first time that DDVP shows differential inhibition of ChE (acetylcholinesterase+butyrylcholinesterase) in various rat brain regions. A single dose of DDVP (1/3 LD(50)) after 16 h of treatment elicited ChE inhibition in the brain regions which was highest in striatum and lowest in cerebellum. The inhibition of ChE by DDVP has been shown to be accompanied with induction of oxidative stress. Further, we investigated the protective potential of the aqueous extract of the roots of Decalepis hamiltonii (DHA), having potent antioxidant constituents, against DDVP-induced ChE inhibition in various rat brain regions. Pretreatment of rats with multiple doses of DHA, 50 and 100mg/kg b.w., for 7 consecutive days did not produce any significant change in ChE activity. Pretreatment of rats with DHA, at high dose, significantly protected against DDVP-induced ChE inhibition in all the brain regions except cerebellum. Pretreatment of rats with DHA, at low dose, showed significant protection in striatum, cortex, and pons against DDVP-induced ChE inhibition. The protective activity of DHA can be attributed to the characterized potent antioxidant constituents which could have an important role in preventing ChE inhibition by inducing the DDVP detoxifying enzymes. We strongly believe that these antioxidant constituents are prospective novel nutriceuticals.

Effect of vitamin A on hexachlorocyclohexane (HCH) toxicity in the rat.

1. Technical hexachlorocyclohexane (HCH) depleted hepatic stores of vitamin A in male albino rats to cause secondary vitamin A deficiency. 2. Toxicity of HCH in rats is augmented by dietary vitamin A-deficiency as evidenced by growth retardation, organ hypertrophies and alterations in the serum and liver levels of the marker enzymes of toxicity. 3. Supplementation of dietary vitamin A to the rats either in adequate (2000 IU/kg diet) or in an excess but not hypervitaminotic level (10(5) IU/kg diet) resulted in significant protection against the toxicity of HCH. 4. The activities of the hepatic xenobiotic metabolizing enzymes were generally low (with the exception of glutathione S-transferase) in the vitamin A-deficient rats compared to those of the vitamin A supplemented diet groups. 5. The results indicated that dietary vitamin A influences the response of male albino rats to HCH toxicity possibly by modulating the activities of hepatic xenobiotic metabolizing enzymes.

Protective role of vitamin A in the male reproductive toxicity of hexachlorocyclohexane (HCH) in the rat.

The reproductive toxicity of the organochlorine insecticide, hexachlorocyclohexane (HCH), was investigated in male albino rats fed a diet free of vitamin A or containing vitamin A at 2000 or 100,000 IU/kg diet. Diets containing 1000 ppm HCH for 7 weeks did not cause testicular toxicity in the vitamin-A-deficient and supplemented rats. However, reproductive toxicity was clearly manifested 2 weeks after withdrawing HCH from the diets and was more pronounced in the vitamin A deficient rats compared to their vitamin A supplemented counterparts. Reduction in the testicular weights was accompanied by atrophy of epididymides and seminal vesicles in the vitamin A deficient rats alone. Inhibition of spermatogenesis was further confirmed by decreased sperm count in the epididymis. Biochemically, the activities of the steroidogenic enzymes were drastically reduced. Supplementation of vitamin A after withdrawal of HCH accelerated the recovery and restored spermatogenesis and enzyme activities in the deficient rats. These results demonstrate the greater susceptibility of the male reproductive system to HCH toxicity during vitamin A deficiency and also the protective effect of vitamin A supplementation.