Targeted isolation of alkaloid from Cyclea Peltata and determination of structural formula of Tetrandrine alkaloid based on NMR studies

Alkaloids are group of chemical entity with proven medicinal properties. This work consolidates the procedure in isolation and structural determination of a bisbenzyl isoquinoline alkaloid from Cyclea peltata with related NMR values and data. Dried routes of Cyclea peltata was extracted using chromatographic techniques monitored using TLC and proton NMR studies. The pure compound isolated was subjected for proton NMR, carbon NMR, HSQC, HMBC, NOESY and COSY spectral experiments. Goal is to document the methods of isolation and NMR experiments involved in structural determination. The compound isolated were bisbenzyl isoquinoline alkaloid with head to head ether bond connection and identified as “Tetrandrine”. Eventhough tetrandrine is a known compound and is reported from many other plants, this time it is isolated and reported from Cyclea peltata (H.f & T).Keywords:- Cyclea peltata; bisbenzyl isoquinoline; NMR; HSQ

Anti-infective activities of secondary metabolites from Vitex pinnata

The phytochemical investigation of Vitex pinnata led to the isolation of a mixture of steroids ß-sitosterol and stigmasterol (1a and 1b) and three known flavonoid identified as 5-hydroxy-3, 7, 4'-trimethoxyflavone (2), 5-hydroxy-7,4'-dimethoxy-flavone (3) and 5-hydroxy-3,3',4',7-tetramethoxyflavone (4). The structures of all isolated compounds were carried out by NMR and mass spectrometry. The isolated compounds were evaluated for their anti-infective activities against Trypanosoma brucei brucei and Mycobacterium marinum. Compound 1-4 showed moderate antitrypanosomal activity with MIC values of 6.25μg/ml, 19.0, 21.0 and 17.0μM, respectively while no activity observed on anti-mycobacterial. This study is the first to report the presence of three flavones and their antitrypanosomal activity from V. pinnata

Response of Methanogens in Arctic Sediments to Temperature and Methanogenic Substrate Availability

Although cold environments are major contributors to global biogeochemical cycles, comparatively little is known about their microbial community function, structure, and limits of activity. In this study a microcosm based approach was used to investigate the effects of temperature, and methanogenic substrate amendment, (acetate, methanol and H2/CO2) on methanogen activity and methanogen community structure in high Arctic wetlands (Solvatnet and Stuphallet, Svalbard). Methane production was not detected in Stuphallet sediment microcosms (over a 150 day period) and occurred within Solvatnet sediments microcosms (within 24 hours) at temperatures from 5 to 40°C, the maximum temperature being at far higher than in situ maximum temperatures (which range from air temperatures of -1.4 to 14.1°C during summer months). Distinct responses were observed in the Solvatnet methanogen community under different short term incubation conditions. Specifically, different communities were selected at higher and lower temperatures. At lower temperatures (5°C) addition of exogenous substrates (acetate, methanol or H2/CO2) had no stimulatory effect on the rate of methanogenesis or on methanogen community structure. The community in these incubations was dominated by members of the Methanoregulaceae/WCHA2-08 family-level group, which were most similar to the psychrotolerant hydrogenotrophic methanogen Methanosphaerula palustris strain E1-9c. In contrast, at higher temperatures, substrate amendment enhanced methane production in H2/CO2 amended microcosms, and played a clear role in structuring methanogen communities. Specifically, at 30°C members of the Methanoregulaceae/WCHA2-08 predominated following incubation with H2/CO2, and Methanosarcinaceaeand Methanosaetaceae were enriched in response to acetate addition. These results may indicate that in transiently cold environments, methanogen communities can rapidly respond to moderate short term increases in temperature, but not necessarily to the seasonal release of previously frozen organic carbon from thawing permafrost soils. However, as temperatures increase such inputs of carbon will likely have a greater influence on methane production and methanogen community structure. Understanding the action and limitations of anaerobic microorganisms within cold environments may provide information which can be used in defining region-specific differences in the microbial processes; which ultimately control methane flux to the atmosphere

Multi-target mode of action of a Clerodane-type diterpenoid from Polyalthia longifolia targeting African trypanosomes.

Natural products have made remarkable contributions to drug discovery and therapy. In this work we exploited various biochemical approaches to investigate the mode of action of 16-α-hydroxycleroda-3,13 (14)-Z-dien-15,16-olide (HDK-20), which we recently isolated from Polyalthia longifolia, on Trypanosoma brucei bloodstream trypomastigotes. HDK20 at concentrations ≥ EC50 (0.4μg/ml) was trypanocidal, with its efect irreversible after only a brief exposure time (<1h). Fluorescence microscopic assessment of DNA confguration revealed severe cell cycle defects after 8h of incubation with the compound, the equivalent of a single generation time. This was accompanied by DNA fragmentation as shown by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling (TUNEL) assays. HDK-20 also induced a fast and profound depolarisation of the parasites’ mitochondrial membrane potential and depleted intracellular ATP levels of T. brucei. Overall, HDK20 showed a multi-target mechanism of action, which provides a biochemical explanation for the promising antitrypanosomatid activity in our previous report

Molecular docking studies on InhA, MabA and PanK enzymes from Mycobacterium tuberculosis of ellagic acid derivatives from Ludwigia adscendens and Trewia nudiflora

There is an urgent need to discover and develop new drugs to combat Mycobacterium tuberculosis, the causative agent of tuberculosis (TB) in humans. In recent years, there has been a renewed interest in the discovery of new anti-TB agents from natural sources. In the present investigation, molecular docking studies were carried out on two ellagic acid derivatives, namely pteleoellagic acid (1) isolated from Ludwigia adscendens, and 3,3′-di-O-methyl ellagic acid 4-O-α-rhamnopyranoside (2) isolated from Trewia nudiflora, to investigate their binding to two enzymes involved in M. tuberculosis cell wall biogenesis, namely 2-trans-enoyl-ACP reductase (InhA) and β-ketoacyl-ACP reductase (MabA), and to pantothenate kinase (PanK type I) involved in the biosynthesis of coenzyme A, essential for the growth of M. tuberculosis. Molecular docking experiments were performed using AutoDock Vina. The crystal structures of InhA, MabA and PanK were retrieved from the RCSB Protein Data Bank (PDB). Isonicotinic-acyl-NADH for InhA and MabA, and triazole inhibitory compound for PanK, were used as references. Pteleoellagic acid showed a high docking score, estimated binding free energy of −9.4 kcal/mol, for the MabA enzyme comparable to the reference compound isonicotinic-acyl-NADH.Knowledge on the molecular interactions of ellagic acid derivatives with essential M. tuberculosis targets could prove a useful tool for the design and development of future anti-TB drugs

Hibiscus acid from hibiscus sabdariffa (malvaceae) has a vasorelaxant effect on the rat aorta

Hibiscus sabdariffa (Malvaceae) is a plant that is widely recognised for its antihypertensive properties; however the constituent(s) responsible for this biological activity are presently unknown. The aim of this study was to identify the potential compounds that are responsible for the vasorelaxant activity of H. sabdariffa. Thereafter, the mechanisms involved in producing the vasorelaxation were investigated. The plant was extracted consecutively with hexane, ethyl acetate and methanol. The methanolic extract was subjected to bioassay-guided fractionation in order to isolate pure compounds that possessed vasorelaxant activity. The vascular effects of the pure compounds were studied on the rat aorta in vitro using myography techniques. Hibiscus acid produced a concentration-dependent relaxation of the rat aorta pre-contracted with either phenylephrine (3 μM) or KCl (60 mM), irrespective of the presence of the endothelium. When the tissue was pre-contracted with phenylephrine, the concentration required to produce 50% relaxation (IC50), was 0.09 ± 0.01 mg/ml. Hibiscus acid had no effect on the phasic contraction induced by phenylephrine in Ca2+-free physiological solution; but it did affect the component of the contraction that is due to Ca2+ influx. In parallel studies, garcinia acid, a diastereoisomer of hibiscus acid, was found to have an almost identical vasorelaxant effect. The vasorelaxant action of both compounds is most likely due to the inhibition of Ca2+ influx via voltage-dependent Ca2+ channels

The individual components of commercial isometamidium do not possess stronger trypanocidal activity than the mixture, nor bypass isometamidium resistance

The four components present in the trypanocidal treatment Samorin, the commercially available formulation of isometamidium, were separated and purified by column chromatography. These compounds as well as the Samorin mixture and the other phenanthridine trypanocide, homidium, were tested on Trypanosoma congolense and wild type, diamidine- and isometamidium-resistant Trypanosoma brucei brucei strains using an Alamar blue drug sensitivity assay. EC50 values obtained suggest that M&B4180A (2) was the most active of the components, followed by M&B38897 (1) in all the strains tested, whereas M&B4596 (4) was inactive. Samorin was found to be significantly more active than any of the individual components alone, against T. congolense and all three T. b, brucei strains. Samorin and all its active constituents displayed reduced activity against the previously characterised isometamidium-resistant strain ISMR1

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist