A novel natural insecticide molecule for grain protection

We have isolated a novel bioactive molecule from the roots of Decalepis hamiltonii that shows insecticidal properties against the stored-product insects Sitophilus oryzae, Rhyzopertha dominica and Callosobruchus chinensis by contact bioassay (LC50: 0.033-0.044 mg/cm2). This compound proved effective as a grain protectant against stored product insects of wheat and green gram. The compound is a novel insecticidal molecule and a promising grain protectant of natural origin. Keywords: Decalepis hamiltonii, Decaleside- I, Insecticidal activity, Stored-product, insect pests, Grain protectio

Reversible antifertility effect of Opuntia elatior Mill. fruit extract

Background: This study was undertaken to evaluate the male antifertility potential of the fruit extract of O. elatior and its reversibility.  Methods: The methanol fruit extract was administered orally (300, 900 mg/kg bw) to male rats for 60 days, and fertility was assessed by analysing spermatogenesis, epididymal sperm count, serum testosterone levels and testicular hydroxysteroid dehydrogenase activity. Fertility was assessed by mating treated rats with normally cycling virgin females. Reversibility of fertility suppression was studied by withdrawal of treatment for two weeks.Results: Epididymal sperm count and motility was markedly reduced up to 75-80% in rats treated for 60 days, without commensurate decline in serum testosterone levels. Testicular steroidogenesis was not affected as evident by the hydroxysteroid dehydrogenase activity. Fertility of the treated rats was suppressed when mated with normally cycling virgin female rats without affecting libido. The fertility suppression was dose-dependent being 100% in the highest dose. Withdrawal of the treatment for two weeks led to recovery of the epididymal sperm count, testicular HSDH activity, serum testosterone levels and the fertility.Conclusions: The methanol extract of the fruit of O. elatior shows reversible male antifertility activity without affecting the serum testosterone levels and libido

Genetic repression of the antioxidant enzymes reduces the lifespan in Drosophila melanogaster

Aging is a biological process associated with gradual loss of function caused by cellular and molecular damages ultimately leading to mortality. Free radicals are implicated in oxidative damage which affects the longevity of organisms. Natural cellular defenses involving antioxidant enzymes delay or prevent oxidative damage and, therefore, influence the aging process and longevity has been shown in many species including Drosophila. We and others have shown that oxidative resistance is an important mechanism in the aging process in Drosophila. Therefore, we hypothesized that repressing endogenous antioxidant defenses shortens longevity in Drosophila. To study the influence of natural defense mechanisms against oxidative stress in aging, we have investigated the effect of genetic repression of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), on longevity in Drosophila using transgenic RNAi flies and in vivo inhibition of the enzymes with chemical inhibitors. RNAi lines of Drosophila viz., UAS-sod1-IR and UAS-cat-IR, are driven ubiquitously using Act5C-Gal4 and Tubulin-Gal4 to achieve the suppression of SOD1 and CAT activities, respectively. We show that genetic repression of SOD1 and CAT by RNAi in transgenic flies led to drastically reduced longevity (SOD1, 77%; CAT, 83%), presenting the evidence for the role of endogenous antioxidant defenses in lifespan extension in Drosophila. Further, our study shows that the enzyme inhibitors, diethyldithiocarbamate and 3-amino-1,2,4-triazole, although lower the enzyme activities in vivo in flies, but did not affect longevity, which could be attributed to the factors such as bioavailability and metabolism of the inhibitors and adaptive mechanisms involving de novo synthesis of the enzymes. Our study of genetic repression using transgenic RNAi provides experimental evidence that extended longevity is associated with endogenous antioxidant defenses and aging is correlated with oxidative stress resistance

Mode of action of the natural insecticide, decaleside involves sodium pump inhibition

Decalesides are a new class of natural insecticides which are toxic to insects by contact via the tarsal gustatory chemosensilla. The symptoms of their toxicity to insects and the rapid knockdown effect suggest neurotoxic action, but the precise mode of action and the molecular targets for decaleside action are not known. We have presented experimental evidence for the involvement of sodium pump inhibition in the insecticidal action of decaleside in the cockroach and housefly. The knockdown effect of decaleside is concomitant with the in vivo inhibition of Na+, K+ -ATPase in the head and thorax. The lack of insecticidal action by experimental ablation of tarsi or blocking the tarsal sites with paraffin correlated with lack of inhibition of Na+- K+ ATPase in vivo. Maltotriose, a trisaccharide, partially rescued the toxic action of decaleside as well as inhibition of the enzyme, suggesting the possible involvement of gustatory sugar receptors. In vitro studies with crude insect enzyme preparation and purified porcine Na+, K+ -ATPase showed that decaleside competitively inhibited the enzyme involving the ATP binding site. Our study shows that the insecticidal action of decaleside via the tarsal gustatory sites is causally linked to the inhibition of sodium pump which represents a unique mode of action. The precise target(s) for decaleside in the tarsal chemosensilla and the pathway linked to inhibition of sodium pump and the insecticidal action remain to be understood

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 ofDecalepis 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

Histology and histochemistry of the oviductal sperm storage pockets of the agamid lizard calotes-versicolor

Some reptiles are known to possess sperm storage in the female genital tract. Examination of the oviduct of the lizard Calotes versicolor shows the presence of sperm in storage pockets of the uterovaginal region throughout the reproductive cycle. Histochemical studies indicate that the epithelium of these pockets resembles the local oviductal epithelium and that a considerable amount of activity of steroidogenic and metabolic enzymes exists

Sperm storage in the oviduct of the tropical rock lizard, Psammophilus dorsalis

The female rock lizard, Psammophilus dorsalis (Agamidae), lays multiple clutches of eggs over a period of 6 months (June-December). The later clutches of eggs are presumably fertilized by sperm stored from earlier matings, since testes and epididymides are regressed after August. Sperm storage is seen in pockets of the anterior vaginal region of the oviduct. Sperm recovered from the uterovaginal region are intact and motile. Discrete granules resembling the secretory granules present in the vas deferens also occur along with sperm in the vaginal sperm storage structures. The PAS-positive granules and acid phosphatase form important components of the secretions present along with sperm in the vaginal sperm storage pockets. The epithelium of the vaginal sperm storage pockets is PAS-positive and contains lipid. Several enzymes, including hydroxysteroid dehydrogenases and hydrolases, are localized histochemically in the epithelium of the vaginal sperm storage pockets. A possible role is suggested for the secretions from the male reproductive tract during sperm storage in the oviduct, in which physiological `'dormancy'' of the sperm during their storage may be maintained by the metabolic `'milieu'' in the vaginal sperm storage pockets by a mechanism similar to that effecting dormancy of the epididymal sperm in the male. (C) 1995 Wiley-Liss, Inc

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 RNAimediated 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

Antitumor effect of decalepis hamiltonii root extract against ehrlich ascites tumor in mice

The antitumor activity of Decalepis hamiltonii root extract (DHA) was investigated in Ehrlich Ascites Tumor (EAT) cell model in mice and the effect was compared with that of the anticancer drug, cyclophosphamide (CP). Treatment of EAT cell bearing mice with aqueous extract of Decalepis hamiltonii (50 mg/kg and 100 mg/kg b.w.) showed a significant reduction in ascites tumor volume, tumor cell counts and increased median survival time (MST). EAT cells induced alterations in hematological profile and the serum marker enzymes aspartate and alanine transaminases (AST, ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were restored by DHA treatment. The antitumor effect of DHA was comparable to that of the anticancer drug cyclophosphamide suggesting the anticancer potential of the root extract of Decalepis hamiltonii

Neuroprotective action of 4-Hydroxyisophthalic acid against paraquat-induced motor impairment involves amelioration of mitochondrial damage and neurodegeneration in Drosophila

Neurodegenerative disorders including Parkinson’s disease (PD) are believed to be caused by oxidative stress and mitochondrial dysfunction. Exposure to environmental agents such as pesticides has been implicated in the etiology of sporadic PD. Paraquat (PQ), a widely used herbicide, induces PD symptoms in laboratory animals including Drosophila. PQ acts as a free radical generator and induces oxidative damage, which is implicated in neuronal cell death. Drosophila model of PQ-induced PD offers a convenient tool for mechanistic studies and, to assess the neuroprotective potential of natural antioxidants. We have investigated the neuroprotective potential of 4-Hydroxyisophthalic acid (DHA-I), a novel bioactive molecule from the roots of Decalepis hamiltonii, against PQ-induced locomotor impairment and neurodegeneration in Drosophila melanogaster. Our study shows that PQ treatment results in movement disorder associated with oxidative stress-mediated mitochondrial damage and neurodegeneration in the brain as evident by ultrastructural observations. Treatment with DHA-I markedly attenuated locomotor deficits, oxidative stress, mitochondrial damage, and neurodegenerative changes induced by PQ in Drosophila. Our results show that DHA-I could be a promising natural antioxidant and a neuroprotective molecule targeting oxidative stress-mediated mitochondrial dysfunction with therapeutic potential for neurodegenerative disorders