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From the stem of Strychnos vanprukii, a gluco-indole alkaloid, 3,4-dehydropalicoside, and a pimarane diterpenoid, 7 beta-hydroxypimara-8,15-dien-14-one, were isolated together with four known alkaloids: palicoside, 3,4,5,6-tetradehydropalicoside, akagerine and 17-O-methylakagerine. The structures of these compounds were elucidated based on spectroscopic evidence.
To further understand the purpose of the traditional processing method of the seeds of Strychnos nux-vomica L. (Loganiaceae) as well as analgesic and anti-inflammatory activities of brucine and brucine N-oxide extracted from this medicinal plant, various pain and inflammatory models were employed in the present study to investigate their pharmacological profiles. Both brucine and brucine N-oxide revealed significant protective effects against thermic and chemical stimuli in hot-plate test and writhing test. However, on different phases they exerted analgesic activities in formalin test. Brucine N-oxide showed stronger inhibitory effect than brucine in carrageenan-induced rat paw edema, both of them significantly inhibited the release of prostaglandin E2 in inflammatory tissue, reduced acetic acid-induced vascular permeability and the content of 6-keto-PGF1a in Freund's complete adjuvant (FCA) induced arthritis rat's blood plasma. In addition, brucine and brucine N-oxide were shown to reduce the content of 5-hydroxytryptamine (5-HT) in FCA-induced arthritis rat's blood plasma, while increase the content of 5-hydroxytryindole-3-acetic acid (5-HIAA) accordingly. These results suggest that central and peripheral mechanism are involved in the pain modulation and anti-inflammation effects of brucine and brucine N-oxide, biochemical mechanisms of brucine and brucine N-oxide are different even though they are similar in chemical structure.
The green monkey orange (Strychnos spinosa Lam., Loganiaceae), a tree indigenous to tropical and subtropical Africa, produces juicy, sweet-sour, yellow fruits containing numerous hard brown seeds. The species has recently been introduced into Israel as a potential new commercial crop. However, little is known about its agronomical performance, fruit development and ripening, or postharvest physiology. The current study shows that during ripening in storage, the peel color changes from green to yellow, accompanied by a climacteric burst of ethylene and carbon dioxide emission. Total soluble solids slightly increased during storage, whereas total titratable acidity and pH did not change significantly. The major sugars that accumulated during ripening in storage were sucrose, glucose, and fructose, and the main acids, citric and malic acids. The main volatiles present in the peel of ripe fruits were phenylpropanoids, trans-isoeugenol being the major compound.
The in vitro antiplasmodial activities of 69 alkaloids from various Strychnos species were evaluated against chloroquine-resistant and chloroquine-sensitive lines of Plasmodium falciparum. The compounds, comprising mainly indolomonoterpenoid alkaloids, exhibited a wide range of biological potencies in the antiplasmodial assays. The most active alkaloids were also tested for cytotoxicity against HCT-116 colon cancer cells to determine their antiplasmodial selectivity. As a result of these studies, structure-activity relationships for these alkaloids have begun to emerge. Alkaloids presenting four types of bisindole skeleton exhibited potent and selective activities against Plasmodium. They were sungucine-type (IC(50) values ranging from 80 nM to 10 microM), longicaudatine-type (IC(50) values ranging from 0.5 to 10 microM), matopensine-type (IC(50) values ranging from 150 nM to 10 microM), and usambarine-type alkaloids. Within the last structural type, isostrychnopentamine (49) and ochrolifuanine A (46) were found to be active against chloroquine-sensitive and -resistant strains (IC(50) values of 100-150 and 100-500 nM, respectively), and dihydrousambarensine (51) exhibited a 30-fold higher activity against the chloroquine-resistant strain (IC(50) = 32 nM) than against the chloroquine-sensitive one.
Three new betulinic acid derivatives, 3beta-O-trans-feruloylbetulinic acid (1), 3beta-O-cis-feruloylbetulinic acid (2), and 3beta-O-cis-coumaroylbetulinic acid (4), along with two known triterpenes, 3beta-O-trans-coumaroylbetulinic acid (3) and ursolic acid (6) were isolated from the leaves and twigs of Strychnos vanprukiiCraib. All isolates showed moderate anti-HIV activity with IC50 values ranging from 3 to 7 microg/mL (5 to 15 microM) in an indicator cell line for HIV infectivity. The structures of the new isolates were elucidated by spectroscopic techniques including 1D and 2D NMR spectroscopy. In addition, the structure of 1 was confirmed by X-ray crystallography.
Three new secoiridoid glucosides, stryspinoside (1) and strychosides A (2) and B (3), were isolated, together with 23 known compounds, from the dried branches of Strychnos spinosa. The structures of the new compounds were determined by spectroscopic means.
[reaction: see text] The intramolecular Diels-Alder reaction between an amidofuran moiety tethered onto an indole component was examined as a strategy for the synthesis of Aspidosperma and Strychnos alkaloids. Furanyl carbamate 13 was acylated using the mixed anhydride 16 to provide amidofuran 12 in 68% yield. Further N-acylation of this indole furnished 17 in 88% yield. Cyclization precursors were prepared by removing the carbamate moiety followed by N-alkylation with the appropriate alkyl halides. Thermolysis of 25 provided the novel tetracyclic ketone 26 in 74% yield.
A quantitative analysis using (1)H-NMR (Q-NMR) has been developed for the determination of strychnine and brucine in Strychnos nux-vomica seeds and stems. The advantages of the method are that no reference alkaloids are needed for calibration curves, the quantification could be directly realized on a crude extract, strychnine and brucine could easily be distinguished, an overall profile of the preparation (including non alkaloid compounds) could be directly obtained, and a very significant time-gain could be achieved, in comparison to conventional HPLC methods, for instance.
A new derivative of strychnopentamine was isolated from the leaves of Strychnos usambarensis. This compound, named chrysopentamine, was identified by detailed spectroscopic methods (UV, IR, HR-ESI-MS, 1D and 2D NMR). Chrysopentamine presented an original hydroxy substitution on C-14 and an aromatization of the ring D of strychnopentamine leading to anhydronium base properties and exhibited strong antiplasmodial properties (IC (50) less than 1 microM).
Isostrychnopentamine (ISP) is an asymmetric indolomonoterpenic alkaloid isolated from the leaves of Strychnos usambarensis. The in vitro antiplasmodial activities against five Plasmodium falciparum cell lines were evaluated: ISP possessed an in vitro IC (50) near 0.1 microM against all P. falciparum cell lines tested (chloroquine-resistant and chloroquine-sensitive lines) and showed antiplasmodial selectivity compared to cytotoxicity on human cell lines. The stage-dependent susceptibility to a short exposure of ISP was then investigated. The ring stage was shown to be the most sensitive one, but all stages were affected by ISP treatment. By means of fluorescence microscopy, it was shown that ISP was not accumulated inside the food vacuole of the parasite. Finally, the in vivo antimalarial activities against the P. berghei NK173 and P. vinckei petteri murine strains were determined. The ED (50) in vivo was about 30 mg/kg/day by the intraperitoneal route (after 4 days treatment).
The composition of the essential oil obtained by hydrodistillation of the leaves of Strychnos spinosa (Loganiaceae) was analysed by GC-FID and GC-MS. Out of twenty-two compounds identified in the oil, the main constituents were palmitic acid (34.3%), linalool (16.0%), and (E)-phytol (6.7%). Since the leaves of this plant are used in African traditional medicine to treat African trypanosomiasis, we evaluated the in vitro activity of the essential oil as well as of 15 of its components on Trypanosoma brucei brucei bloodstream forms and on mammalian cells (J774 murine macrophages) to evaluate the selectivity of the antitrypanosomal effect. The essential oil was active on the parasites without a great selectivity [IC50 on T. b. brucei = 13.5 microg/mL with a selectivity index (SI) of 4.4]. (E)-Nerolidol, a minor component of the hydrodistillate, as well as linalool, were shown to have a more potent and selective effect on the trypanosomes [IC50 = 1.7 and 2.5 microg/mL (7.6 and 16.3 microM) with SI = 35.7 and > 40, respectively]. These two oxygenated terpenes have promising activity and it would be of interest to study their mechanism of action as well as their in vivo activity.
A new strychnobrasiline derivative, 12-hydroxy-10,11-dimethoxystrychnobrasiline 1, has been isolated from the stem barks of Strychnos mattogrossensis. Its structure was established by spectroscopy analysis (1D and 2D NMR, MS, IR, UV) and literature data comparison. Two other known indoline alkaloids were also obtained from the heartwood, 12-hydroxy-11-methoxystrychnobrasiline 2 and strychnobrasiline 3.
Isostrychnopentamine (ISP) is an indolomonoterpenic alkaloid that is present in the leaves of Strychnos usambarensis, a well known African shrub or little tree. The roots contain quaternary alkaloids, which are used to make a curare-like arrow poison. However, tertiary alkaloids isolated from the same plant possess cytotoxic activities against mammalian cells and protozoa. The effect of ISP has been investigated on the growth and viability of HCT-116 colon cancer cells during their exponentially growing phase. ISP induced apoptotic cell death as shown by the translocation of phosphatidylserine from the inner layer to the outer layer of the plasma membrane, chromatin condensation, DNA fragmentation, and caspase-3 and -9 activation. ISP provoked also cell cycle arrest in the G(2)-M phase. We also showed that the expression of p53 was not modified in ISP-treated cells, but that p21 was induced in a p53-independent manner. Finally, we demonstrated that ISP did not affect the catalytic activity of human topoisomerases I and II. In conclusion, ISP, which promotes cell death by a p53-independent apoptotic pathway, could be an interesting lead for cancer chemotherapy.
Strychnos pseudoquina ST. HIL. (Loganiaceae) was investigated for its ability to protect the gastric mucosa against injuries caused by non-steroidal anti-inflammatory drugs (piroxicam) and a necrotizing agent (HCl/EtOH) in mice. The MeOH extract and enriched alkaloidic fraction (EAF) provided significant protection in experimental models wheer used at doses of 250 and 1000 mg/kg. In vivo tests were carried out to evaluate for possible toxic effects and no mortality was observed up to the 5 g/kg dose level. Phytochemical investigation led to the isolation of a new indole alkaloid, which elucidated the observed pharmacological effects.
AIM: To study the pharmacokinetic process about the concentration in rat plasma of the alkaloids from processed seeds of Strychnos nux-vomica with RP-HPLC method. METHODS: Hypersil BDS C18 column was used and the mobile phase consisted of acetonitrile-water at the flow rate of 0.8 mL.min-1. The UV detection wave length was 254 nm. RESULTS: The concentration-time data of strychnine, brucine, strychnine N-oxide and brucine N-oxide were all in accordance with an open two-compartment model after i.v. alkaloids. Their parameters were as follows: T1/2 alpha were (8 +/- 5), (4 +/- 3), (6.2 +/- 1.7) and (3.0 +/- 0.8) min, T1/2 beta were (262 +/- 125), (416 +/- 131), (285 +/- 50) and (342 +/- 141) min, CL were (17 +/- 4), (21 +/- 12), (1.9 +/- 1.8) and (2.8 +/- 1.1) mL.min-1, Vc were (1.4 +/- 0.5), (1.7 +/- 1.1), (0.24 +/- 0.16) and (0.23 +/- 0.06) L.kg-1, Vd were (6.0 +/- 1.2), (12 +/- 7), (0.8 +/- 0.6) and (1.5 +/- 0.6) L.kg-1, AUC were (57,578 +/- 25,578), (35,240 +/- 15,616), (93,088 +/- 22,375) and (177,712 +/- 120,110) h.microgram.L-1, respectively. CONCLUSION: The method is a good reference for pharmacokinetics in human bodies.
Three alkaloids of the stem bark of Strychnos dolichothyrsa Gilg ex Onochie et Hepper (Loganiaceae) were isolated and identified as caracurine V and its mono- and di-N-oxide by comparison with synthesized compounds. 13C-NMR was used to confirm the structure of the N-oxides. The muscle relaxant activity and the toxicity of the N-oxides were less than those of caracurine V.
13C-NMR spectral assignments of the Strychnos alkaloids brucine and strychnine have been reported by numerous investigators. One recent report contained several disparities in the assignments that were attributable to incorrect determinations of spin multiplicities. The source of the inaccuracies in the spin-multiplicity determinations of very complex molecules is discussed, and several additional techniques for the determination of these multiplicities are described that are less subject to interpretational errors than the conventional and routinely employed single-frequency off-resonance decoupling methods. These procedures are applied using brucine as a representative example.
A review of the phytochemistry of African Strychnos species and the biological activities of some species as well as of some individual alkaloids isolated from them is presented. Although pharmacological studies of 48 species showed that muscle-relaxant and/or convulsant properties were generally present, antimicrobial, cytotoxic and hypotensive properties among others have also been demonstrated by some of the species and/or alkaloids.