Cytotoxicity and antiangiogenic activity of grandisin

Objectives The antitumoural properties of grandisin, a tetrahydrofuran neolignan from Piper solmsianum, were investigated by in-vitro and in-vivo assays using the Ehrlich ascites tumoural (EAT) model. Methods Viability of the tumour cells was evaluated by Trypan blue exclusion and MTT methods, after incubation with grandisin (0.017-2.3 mu M). The effects of grandisin on the activity of caspase-3, -6, -8, and -9 were also investigated using colorimetric protease kits. In-vivo studies were performed in EAT-bearing mice treated intraperitoneally with 2.5, 5 or 10 mg/kg grandisin for 10 days. Key findings Grandisin inhibited the growth of EAT cells, by both methods, with IC50 values less than 0.25 mu M. The results showed that the activity of all the caspases studied increased in grandisin-treated cells, when compared with control, non-treated cells. Administering grandisin to EAT-bearing mice increased survival of the animals, in a dose-dependent manner. Simultaneously, we detected a 66.35% reduction of intraperitoneal tumour cell burden in the animals treated with 10 mg/kg grandisin. Additionally, in these animals, the marked increase of vascular endothelial growth factor (VEGF) levels, induced by EAT development, was decreased with treatment with grandisin, resulting in a reduction of 32.1% of VEGF levels in the peritoneal washing supernatant, when compared with the control. Conclusions The results demonstrated that grandisin induced in-vitro cytotoxicity and antiangiogenic effects in mice while it acted against tumour evolution, prolonging host survival.

In vitro basal cytotoxicity assay applied to estimate acute oral systemic toxicity of grandisin and its major metabolite

Preclinical investigations can start with preliminary in vitro studies before using animal models. Following this approach, the number of animals used in preclinical acute toxicity testing can be reduced. In this study, we employed an in-house validated in vitro cytotoxicity test based on the Spielmann approach for toxicity evaluation of the lignan grandisin, a candidate anticancer agent, and its major metabolite. the 4-O-demethylgrandisin, by neutral red uptake (NRU) assay, on mouse fibroblasts Balb/c 3T3 cell line. Using different concentrations of grandisin and its major metabolite (2.31; 1.16; 0.58; 0.29; 0.14; 0.07; 0.04; 0.002 mu M) in Balb/c 3T3-A31 NRU cytotoxicity assay, after incubation for 48 h, we obtained IC(50) values for grandisin and its metabolite of 0.078 and 0.043 mu M, respectively. The computed LD(50) of grandisin and 4-O-demethylgrandisin were 617.72 and 429.95 mg/kg, respectively. Both were classified under the Globally Harmonized System as category 4. Since pharmacological and toxicological data are crucial in the developmental stages of drug discovery, using an in vitro assay we demonstrated that grandisin and its metabolite exhibit distinct toxicity profiles. Furthermore, results presented in this work can contribute to reduce the number of animals required in subsequent pharmacological/toxicological studies. (C) 2010 Elsevier GmbH. All rights reserved.

Disruption of Chrysomya megacephala Growth Caused by Lignan Grandisin

The toxicity of tetrahydrofuran lignan grandisin was evaluated against larvae of Chrysomya megacephala F. (Diptera: Calliphoridae). The bioassay involved topical treatment on larvae, topical treatment oil egg masses, and incorporation in the larval diet. Grandisin showed inhibition of postembryonic development by ovicidal (30%) and larvicidal (38%) effects and reduced larval weight (4 mg), when topically applied oil egg masses and starving larvae (L1) at a concentration of 100 mu g/mu l. These findings elucidated the effect of grandisin on the C. megacephala life cycle and its potential to control C. megacephala populations.

LARVICIDAL ACTIVITY OF GRANDISIN AGAINST AEDES AEGYPTI

Dengue is a tropical disease caused by an arbovirus transmitted by the mosquito Aedes aegypti. Because no effective vaccine is available for the disease, the strategy for its prevention has focused on vector control by the use of natural insecticides. The aim of this study was to evaluate the larvicidal activity of the lignan grandisin, a leaf extract from Piper solmsianum, against Ae. aegypti.

Metabolism of (-)-grandisin from Piper solmsianum in Coleoptera and Lepidoptera species

The biotransformation of the major Piper solmsianum leaf phenylpropanoids, such as the tetrahydrofuran lignan grandisin and derivatives was investigated in the beetle Naupactus bipes as well as in the caterpillars Heraclides hectorides and Quadrus u-lucida. Analysis of fecal material indicated that metabolism occurred mainly through mono- and di-O-demethylation at para positions of 3,4,5-trimethoxyphenyl rings of tetrahydrofuran lignans during digestion by these insects. Additionally, 3-hydroxy-4,5-dimethoxycinnamyl and 3,4,5-trimethoxycinnamyl alcohols were identified in fecal extracts of N. bipes. (C) 2008 Elsevier Ltd. All rights reserved.

Chemoprotective effect of the tetrahydrofuran lignan grandisin in the in-vivo rodent micronucleus assay

Objectives The chemoprotective effect of the tetrahydrofuran lignan grandisin against DNA damage induced by cyclophosphamide (200 mg/kg) has been evaluated using the in vitro rodent micronucleus assay. Methods The effects of a daily oral administration of grandisin (2, 4, or 8 mg/kg) for five days before exposure to cyclophosphamide on the frequency of micronucleus in the bone marrow of normal mice exposed and unexposed to cyclophosphamide were investigated (n = 5 per group). Electrochemical measurements were applied to investigate whether the antimutagenic effects of grandisin could be, at least in part, a consequence of its or its metabolite`s antioxidant properties. Key findings Grandisin did not show mutagenic effects on the bone marrow cells of exposed mice. On the other hand, the oral administration of grandisin (2, 4, or 8 mg/kg) per day reduced dose-dependently the frequency of micronucleus, induced by cyclophosphamide, in all groups studied. Cyclic voltammograms showed two peaks for a grandisin metabolite, which were absent for grandisin. Conclusions Under the conditions tested herein, this study has shown that mice treated with grandisin presented, in a dose-dependent manner, a protective effect against cyclophosphamide-induced mutagenicity. This effect could be, at least in part, associated to grandisin bioactivation. These data open new perspectives for further investigation into the toxicology and applied pharmacology of grandisin.

In vitro Metabolism of Grandisin, a Lignan with Anti-chagasic Activity

Tetrahydrofuran lignans represent a well-known group of phenolic compounds capable of acting as antiparasitic agents. In the search for new medicines for the treatment of Chagas disease, one promising compound is grandisin which has shown significant activity on trypomastigote forms of Trypanosoma cruzi. In this work, the in vitro metabolism of grandisin was studied in the pig cecum model and by biomimetic phase I reactions, aiming at an ensuing a preclinical pharmacokinetic investigation. Although grandisin exhibited no metabolization by the pig microbiota, one putative metabolite was formed in a biomimetic model using Jacobsen catalyst. The putative metabolite was tested against T. cruzi revealing loss of activity in comparison to grandisin.

Grandisin caused morphological changes larval and toxicity on Aedes aegypti

Dengue is a tropical disease caused by an arbovirus transmitted by Aedes aegypti. Since no effective vaccine is available for treating dengue, the present study focused on population vector control through investigating the use of the lignan grandisin, isolated from Piper solmsianum C. DC., Piperaceae, against the larvae of A. aegypti. Grandisin caused larval (L3) mortality at LC50 150 µg/mL. Histological analysis on A. aegypti larvae treated with grandisin (LC50 50 µg/mL) showed changes in the anterior-middle midgut, with intense tissue destruction and cell disorganization.

Three new compounds from Kadsura longipedunculata

Two new tetrahydrofuran lignans, kadlongirins A and B (1, 2), a new cadinane-type sesquiterpenoid, 2,7-dihydroxy-1 1,1 2-dehydrocalamenene (3), together with seven known lignans, grandisin, fragransin B-1, vladirol F, kadsuralignan C, otobaphenol, isoanwu

Secondary Metabolites from the Phloem of Piper solmsianum (Piperaceae) in the Honeydew of Edessa meditabunda

Introduction The phytochemistry of species of the genus Piper has been studied extensively, including Piper solmsianum. However, no studies have addressed the phytochemistry of the sap content of Piper species. Objective To evaluate the transferring of secondary compounds from the saps of P. solmsianum to the honeydew of Edessa meditabunda. Methodology The honeydew of E. meditabunda and saps of P. solmsianum were analysed by GC-MS, H-1-NMR and LC-MS. Results The lignan (-)-grandisin and the phenylpropanoid (E)-isoelemicin were detected in both saps of P. solmsianum and honeydew of E. meditabunda. Conclusion Analysis of honeydew secreted by the sap-sucking insect E. meditabunda indicated that (-)-grandisin and (E)-isoelemicin are absorbed from the phloem of Piper solmsianum. Copyright (c) 2012 John Wiley & Sons, Ltd.