The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
K Cimanga - One of the best experts on this subject based on the ideXlab platform.
-
inhibitors of xanthine oxidase and scavengers of superoxide anions from Cryptolepis sanguinolenta lindl schlechter periplocaceae
Pharmacy and Pharmacology Communications, 2000Co-Authors: K Cimanga, Luc Pieters, L Tona, K Kambu, T De Bruyne, Sandra Apers, Paul Cos, P Bakana, D Vanden Berghe, A J VlietinckAbstract:Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae) is a medicinal plant used in some African countries against infectious and parasitic diseases. Six of its constituent alkaloids have been isolated from the root bark, identified spectroscopically as cryptoquindolinine (1), quindoline (2), neocryptolepine (3), cryptolepine (4), 11-hydroxycryptolepine (5) and biscryptolepine (6), and their interaction with the xanthine-xanthine oxidase enzyme system has been tested. Compound 5 has been shown to inhibit xanthine oxidase and act as a scavenger of superoxide anions. Alkaloids 1–4 and 6 were devoid of effect in both assays at the highest test concentration of 100 mM. These findings suggest the importance, in the manifestation of both activities, of the hydroxyl group present in 5 but not in the other alkaloids.
-
antiamoebic and phytochemical screening of some congolese medicinal plants
Journal of Ethnopharmacology, 1998Co-Authors: L Tona, K Cimanga, K Kambu, N P Ngimbi, A J VlietinckAbstract:Abstract Results from the in vitro antiamoebic activity of some Congolese plant extracts used as antidiarrhoeic in traditional medicine indicated that of 45 plant extracts tested, 35 (77.78%) exhibited an antiamoebic activity and 10 (22.22%) were inactive. The highest activity (MIC μ g/ml) was obtained with extracts from root bark of Paropsia brazzeana, Cryptolepis sanguinolenta, Alchornea cordifolia, Hensia pulchella, Maprounea africana, Rauwolfia obscura and Voacanga africana , leaves and stem bark of Psidium guajava , stem bark of Dialum englerianum, Harungana madagascariensis and Mangifera indica , mature seeds of Carica papaya , and leaves of Morinda morindoides and Tithonia diversifolia . Metronidazole used as reference product showed a more pronounced activity than that of all plant extracts tested.
-
antibacterial and antifungal activities of neocryptolepine biscryptolepine and cryptoquindoline alkaloids isolated from Cryptolepis sanguinolenta
Phytomedicine, 1998Co-Authors: K Cimanga, Luc Pieters, L Tona, K Kambu, T De Bruyne, D Vanden Berghe, J Totte, A J VlietinckAbstract:From the 80% EtOH extract of Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaeae) root bark, a cryptolepine isomer named neocryptolepine, and two dimeric alkaloids named biscryptolepine and cryptoquindoline were isolated. These compounds were tested for their putative antibacterial and antifungal activities. Results have indicated that neocryptolepine showed an antibacterial activity against Gram-positive bacteria (MIC < 100 μg/ml), but was less acive against Gram-negative bacteria. It also inhibited the growth of the yeast C. albicans. Biscryptolepine exhibited only an activity against some Gram-positive bacteria (MIC = 62.5 or 31 μg/ml) while cryptoquindoline did not shown an activity against all selected microorganisms. The antibacterial activity of neocryptolepine and biscryptolepine is bacteriostatic rather than bactericidal. No antifungal activity could be observed for all alkaloids in our test system at the highest test concentration of 100 μg/ml.
-
in vitro and in vivo antiplasmodial activity of cryptolepine and related alkaloids from Cryptolepis sanguinolenta
Journal of Natural Products, 1997Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, A J Vlietinck, C A TurgerAbstract:Three different extracts and four alkaloids from the root bark of Cryptolepis sanguinolenta have been assessed in vitro against Plasmodium falciparum D-6 (chloroquine-sensitive strain), K-1, and W-2 (chloroquine-resistant strains). Cryptolepine (1) and its hydrochloride (2), 11-hydroxycryptolepine (3), and neocryptolepine (5) showed a strong antiplasmodial activity against P. falciparum chloroquine-resistant strains. Quindoline (4) was less active. The highest activity was obtained with compound 1. In vivo tests on infected mice showed that crytpolepine (1), when tested as its hydrochloride (2), exhibited a significant chemosuppressive effect against Plasmodium berghei yoelii and Plasmodium berghei berghei, while 1 had the same effect against P. berghei yoelii only. Compounds 3 and 4 did not show activity in this in vivo test system.
-
new alkaloids from Cryptolepis sanguinolenta
Tetrahedron Letters, 1996Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, M Claeys, A J VlietinckAbstract:Neocryptolepine and biscryptolepine, two new alkaloids, were isolated from the root bark extract of the African medicinal plant, Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae), and their structures elucidated on the basis of spectral evidence. The 1H and 13C NMR assignments of cryptoquindoline, a known artefact, were revised.
Alexandra Paulo - One of the best experts on this subject based on the ideXlab platform.
-
chemotaxonomic analysis of the genus Cryptolepis
Biochemical Systematics and Ecology, 2003Co-Authors: Alexandra Paulo, Peter J HoughtonAbstract:Abstract A chemotaxonomic study is made on the basis of a phytochemical screening of the leaves of 60% of the African Cryptolepis species and the review of the secondary metabolites identified in the genus Cryptolepis , subfamily Periplocoideae and related families Asclepiadaceae and Apocynaceae. Our study indicates that the chemistry of the genus Cryptolepis is in agreement with its taxonomic position within the taxon Periplocaceae/Periplocoideae and also that the chemical evidence obtained so far is consistent with the idea that the taxon Periplocaceae/Periplocoideae is an evolutionary link between the families Apocynaceae and Asclepiadaceae. Our observations also strengthens the argument that the taxon Periplocaceae/Periplocoideae should be considered an independent family.
-
steroidal alkaloids from Cryptolepis obtusa
ChemInform, 2000Co-Authors: Alexandra Paulo, Elsa T Gomes, Luisa M Jimeno, Peter J HoughtonAbstract:AbstractTwo novel diglycosylated steroidal alkaloids of 5D-pregnene nucleus, named obtusine-20(R)-O-[b-thevetopyranosyl-(1 44)-b-cymaropyranoside] and obtusolactam-20(R)-O-[b-thevetopyranosyl-(1 44)-b-cymaropyranoside], together with the known b-sitosteryl-3-O-b-glucopyranoside were isolated from the roots of Cryptolepis obtusa N. E. Br. # 2000 Elsevier Science Ltd. Allrights reserved. Keywords: Cryptolepis obtusa; Periplocaceae or Asclepiadaceae; Saponins; 5D-pregnene steroidal alkaloids 1. IntroductionThe genus Cryptolepis R. Br. includes about 20species distributed throughout the tropical regions ofAfrica, Madagascar, Asia, Australia and Papua NewGuinea. The genus is assigned either to the Periplocoi-deae subfamily of the Asclepiadaceae or to the newlycreated family Periplocaceae (Hutchinson & Dalziel,1963; Cronquist, 1981), a taxon poorly investigatedfrom the chemical point of view. Continuing our stu-dies on the chemistry and biological activity of Crypto-lepis species (Paulo, Pimentel, Viegas, Pires, Duarte C Paulo, Duarte & Gomes, 1994; Paulo,Gomes & Houghton, 1995; Paulo, Gomes, Duarte,Perrett & Houghton, 1997; Paulo, Gomes, Steele, War-hurst & Houghton, in press) the roots of Cryptolepisobtusa N. E. Br. were analysed for their major second-ary metabolites. The aqueous extracts of roots of C.obtusa are traditionally used in Mozambique as ananti-abortive remedy, vermifuge and to treat abdomi-nal pains (Mendes & Jansen, 1984). To our knowledge,no phytochemical work has been reported on the rootsof this species. We describe herein the isolation andstructural elucidation, on the basis of extensive high-field NMR studies, of two new diglycosylated steroidalalkaloids (1 and 2) with a novel 5D-pregnene skeleton.2. Results and discussionTLC using general spray reagents (Wagner, Bladt &Zgainski, 1984) of the chloroformic crude extract ofthe roots of C. obtusa revealed the presence of alka-loidal and non-alkaloidal saponins as major constitu-ents. The chloroformic extract was chromatographedon a silica gel column and the alkaloid fractionobtained was further fractionated and purified bysemi-preparative HPLC and prep. TLC to a•ord com-pounds 1 and 2.Compound 1 gave positive reaction with the Dra-gendor• spray reagent and for that reason it was sus-pected to be an alkaloid. The molecular formula ofC
-
antiplasmodial activity of Cryptolepis sanguinolenta alkaloids from leaves and roots
Planta Medica, 2000Co-Authors: Alexandra Paulo, Elsa T Gomes, Jonathan C P Steele, Dave C Warhurst, Peter J HoughtonAbstract:The roots of Cryptolepis sanguinolenta have been investigated for their chemical composition since 1931 but so far no studies on the leaves have been reported although they are used in traditional medicine in Guinea-Bissau. Two new alkaloids identified as cryptolepinoic acid (1) and methyl cryptolepinoate (2) and the known alkaloids cryptolepine (4), hydroxycryptolepine (5/5a) and quindoline (6), were isolated from the ethanolic and chlorophormic leaf extracts. Aqueous and ethanolic extracts of the leaves and roots and seven alkaloids isolated from those extracts were tested in vitro against Plasmodium falciparum K1 (multidrug-resistant strain) and T996 (chloroquine-sensitive clone). All the extracts were shown to give 90% inhibition of P. falciparum K1 growth at concentrations < 23 micrograms/ml. Cryptolepine (4) was the most active alkaloid tested with IC50 values (0.23 microM to K1; 0.059 microM to T996) comparable with chloroquine (0.26 microM to K1; 0.019 microM to T996). The indolobenzazepine alkaloid cryptoheptine (7) was the second most active with IC50 values of 0.8 microM (K1) and 1.2 microM (T996). Cryptolepinoic acid (1) showed no significant activity while its ethyl ester derivative 3 was active against P. falciparum K1 (IC50 = 3.7 microM). All the indoloquinoline alkaloids showed cross-resistance with chloroquine but not the indolobenzazepine alkaloid 7. It was noticed that alkaloids with weakly basic characteristics were active whereas other structurally related alkaloids with different acid-base profiles were inactive. These observations are in agreement with the antimalarial mechanism of action for quinolines.
-
new alkaloids from Cryptolepis sanguinolenta
ChemInform, 1996Co-Authors: Alexandra Paulo, Elsa T Gomes, Peter J HoughtonAbstract:An extract of Cryptolepis sanguinolenta yielded five alkaloids. Two of these were the known compounds cryptolepine [1] and quindoline [2]. Three of the compounds have not been reported previously and were named hydroxycryptolepine [3], cryptoheptine [4], and cryptoquindoline [5]. Compound 5 was shown to be an artifact.
-
Cryptolepis sanguinolenta activity against diarrhoeal bacteria
Journal of Ethnopharmacology, 1994Co-Authors: Alexandra Paulo, Madalena Pimentel, Silvia Viegas, Ilda Pires, Aida Duarte, Jose Cabrita, Elsa T GomesAbstract:Cryptolepine is the main alkaloid of Cryptolepis sanguinolenta (Lindl.) Schlechter, a plant used in traditional medicine in West Africa. The minimal inhibitory concentrations (MICs) of cryptolepine, ethanol and aqueous extracts of Cryptolepis sanguinolenta root were determined for 65 strains of Campylobacter jejuni, 41 strains of Campylobacter coli isolated from sporadic cases of gastroenteritis in Portugal and 86 strains of Vibrio cholerae isolated from patients with enteric infections in Angola, Brazil and Portugal. The ethanol extract activity against Campylobacter strains (MIC90% = 25 micrograms/ml) is higher than that of co-trimoxazole and sulfamethoxazole and Campylobacter strains susceptibility for cryptolepine (MIC90% = 12.5 micrograms/ml) is equal for ampicillin. The ethanol extract and cryptolepine show some activity against the Vibrio cholerae strains, although their activities are lower than that of tetracycline. The results suggest that these roots could be a therapeutic alternative for bacterial etiologic diarrhoea in West Africa.
Elsa T Gomes - One of the best experts on this subject based on the ideXlab platform.
-
steroidal alkaloids from Cryptolepis obtusa
ChemInform, 2000Co-Authors: Alexandra Paulo, Elsa T Gomes, Luisa M Jimeno, Peter J HoughtonAbstract:AbstractTwo novel diglycosylated steroidal alkaloids of 5D-pregnene nucleus, named obtusine-20(R)-O-[b-thevetopyranosyl-(1 44)-b-cymaropyranoside] and obtusolactam-20(R)-O-[b-thevetopyranosyl-(1 44)-b-cymaropyranoside], together with the known b-sitosteryl-3-O-b-glucopyranoside were isolated from the roots of Cryptolepis obtusa N. E. Br. # 2000 Elsevier Science Ltd. Allrights reserved. Keywords: Cryptolepis obtusa; Periplocaceae or Asclepiadaceae; Saponins; 5D-pregnene steroidal alkaloids 1. IntroductionThe genus Cryptolepis R. Br. includes about 20species distributed throughout the tropical regions ofAfrica, Madagascar, Asia, Australia and Papua NewGuinea. The genus is assigned either to the Periplocoi-deae subfamily of the Asclepiadaceae or to the newlycreated family Periplocaceae (Hutchinson & Dalziel,1963; Cronquist, 1981), a taxon poorly investigatedfrom the chemical point of view. Continuing our stu-dies on the chemistry and biological activity of Crypto-lepis species (Paulo, Pimentel, Viegas, Pires, Duarte C Paulo, Duarte & Gomes, 1994; Paulo,Gomes & Houghton, 1995; Paulo, Gomes, Duarte,Perrett & Houghton, 1997; Paulo, Gomes, Steele, War-hurst & Houghton, in press) the roots of Cryptolepisobtusa N. E. Br. were analysed for their major second-ary metabolites. The aqueous extracts of roots of C.obtusa are traditionally used in Mozambique as ananti-abortive remedy, vermifuge and to treat abdomi-nal pains (Mendes & Jansen, 1984). To our knowledge,no phytochemical work has been reported on the rootsof this species. We describe herein the isolation andstructural elucidation, on the basis of extensive high-field NMR studies, of two new diglycosylated steroidalalkaloids (1 and 2) with a novel 5D-pregnene skeleton.2. Results and discussionTLC using general spray reagents (Wagner, Bladt &Zgainski, 1984) of the chloroformic crude extract ofthe roots of C. obtusa revealed the presence of alka-loidal and non-alkaloidal saponins as major constitu-ents. The chloroformic extract was chromatographedon a silica gel column and the alkaloid fractionobtained was further fractionated and purified bysemi-preparative HPLC and prep. TLC to a•ord com-pounds 1 and 2.Compound 1 gave positive reaction with the Dra-gendor• spray reagent and for that reason it was sus-pected to be an alkaloid. The molecular formula ofC
-
antiplasmodial activity of Cryptolepis sanguinolenta alkaloids from leaves and roots
Planta Medica, 2000Co-Authors: Alexandra Paulo, Elsa T Gomes, Jonathan C P Steele, Dave C Warhurst, Peter J HoughtonAbstract:The roots of Cryptolepis sanguinolenta have been investigated for their chemical composition since 1931 but so far no studies on the leaves have been reported although they are used in traditional medicine in Guinea-Bissau. Two new alkaloids identified as cryptolepinoic acid (1) and methyl cryptolepinoate (2) and the known alkaloids cryptolepine (4), hydroxycryptolepine (5/5a) and quindoline (6), were isolated from the ethanolic and chlorophormic leaf extracts. Aqueous and ethanolic extracts of the leaves and roots and seven alkaloids isolated from those extracts were tested in vitro against Plasmodium falciparum K1 (multidrug-resistant strain) and T996 (chloroquine-sensitive clone). All the extracts were shown to give 90% inhibition of P. falciparum K1 growth at concentrations < 23 micrograms/ml. Cryptolepine (4) was the most active alkaloid tested with IC50 values (0.23 microM to K1; 0.059 microM to T996) comparable with chloroquine (0.26 microM to K1; 0.019 microM to T996). The indolobenzazepine alkaloid cryptoheptine (7) was the second most active with IC50 values of 0.8 microM (K1) and 1.2 microM (T996). Cryptolepinoic acid (1) showed no significant activity while its ethyl ester derivative 3 was active against P. falciparum K1 (IC50 = 3.7 microM). All the indoloquinoline alkaloids showed cross-resistance with chloroquine but not the indolobenzazepine alkaloid 7. It was noticed that alkaloids with weakly basic characteristics were active whereas other structurally related alkaloids with different acid-base profiles were inactive. These observations are in agreement with the antimalarial mechanism of action for quinolines.
-
new alkaloids from Cryptolepis sanguinolenta
ChemInform, 1996Co-Authors: Alexandra Paulo, Elsa T Gomes, Peter J HoughtonAbstract:An extract of Cryptolepis sanguinolenta yielded five alkaloids. Two of these were the known compounds cryptolepine [1] and quindoline [2]. Three of the compounds have not been reported previously and were named hydroxycryptolepine [3], cryptoheptine [4], and cryptoquindoline [5]. Compound 5 was shown to be an artifact.
-
Cryptolepis sanguinolenta activity against diarrhoeal bacteria
Journal of Ethnopharmacology, 1994Co-Authors: Alexandra Paulo, Madalena Pimentel, Silvia Viegas, Ilda Pires, Aida Duarte, Jose Cabrita, Elsa T GomesAbstract:Cryptolepine is the main alkaloid of Cryptolepis sanguinolenta (Lindl.) Schlechter, a plant used in traditional medicine in West Africa. The minimal inhibitory concentrations (MICs) of cryptolepine, ethanol and aqueous extracts of Cryptolepis sanguinolenta root were determined for 65 strains of Campylobacter jejuni, 41 strains of Campylobacter coli isolated from sporadic cases of gastroenteritis in Portugal and 86 strains of Vibrio cholerae isolated from patients with enteric infections in Angola, Brazil and Portugal. The ethanol extract activity against Campylobacter strains (MIC90% = 25 micrograms/ml) is higher than that of co-trimoxazole and sulfamethoxazole and Campylobacter strains susceptibility for cryptolepine (MIC90% = 12.5 micrograms/ml) is equal for ampicillin. The ethanol extract and cryptolepine show some activity against the Vibrio cholerae strains, although their activities are lower than that of tetracycline. The results suggest that these roots could be a therapeutic alternative for bacterial etiologic diarrhoea in West Africa.
-
in vitro antibacterial screening of Cryptolepis sanguinolenta alkaloids
Journal of Ethnopharmacology, 1994Co-Authors: Alexandra Paulo, Aida Duarte, Elsa T GomesAbstract:The ethanol and aqueous crude extracts and five alkaloids isolated from the roots of Crytolepis sanguinolenta (Lindl.) Schlechter were screened for antibacterial activity against 7 reference strains by the twofold serial broth microdilution assay. The ethanol extract and the alkaloids cryptolepine and cryptoheptine inhibited the growth of all strains tested except that of Pseudomonas aeruginosa.
A J Vlietinck - One of the best experts on this subject based on the ideXlab platform.
-
antibacterial and antifungal activities of neocryptolepine biscryptolepine and cryptoquindoline alkaloids isolated from Cryptolepis sanguinolenta
Phytomedicine, 1998Co-Authors: K Cimanga, Luc Pieters, L Tona, K Kambu, T De Bruyne, D Vanden Berghe, J Totte, A J VlietinckAbstract:From the 80% EtOH extract of Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaeae) root bark, a cryptolepine isomer named neocryptolepine, and two dimeric alkaloids named biscryptolepine and cryptoquindoline were isolated. These compounds were tested for their putative antibacterial and antifungal activities. Results have indicated that neocryptolepine showed an antibacterial activity against Gram-positive bacteria (MIC < 100 μg/ml), but was less acive against Gram-negative bacteria. It also inhibited the growth of the yeast C. albicans. Biscryptolepine exhibited only an activity against some Gram-positive bacteria (MIC = 62.5 or 31 μg/ml) while cryptoquindoline did not shown an activity against all selected microorganisms. The antibacterial activity of neocryptolepine and biscryptolepine is bacteriostatic rather than bactericidal. No antifungal activity could be observed for all alkaloids in our test system at the highest test concentration of 100 μg/ml.
-
in vitro and in vivo antiplasmodial activity of cryptolepine and related alkaloids from Cryptolepis sanguinolenta
Journal of Natural Products, 1997Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, A J Vlietinck, C A TurgerAbstract:Three different extracts and four alkaloids from the root bark of Cryptolepis sanguinolenta have been assessed in vitro against Plasmodium falciparum D-6 (chloroquine-sensitive strain), K-1, and W-2 (chloroquine-resistant strains). Cryptolepine (1) and its hydrochloride (2), 11-hydroxycryptolepine (3), and neocryptolepine (5) showed a strong antiplasmodial activity against P. falciparum chloroquine-resistant strains. Quindoline (4) was less active. The highest activity was obtained with compound 1. In vivo tests on infected mice showed that crytpolepine (1), when tested as its hydrochloride (2), exhibited a significant chemosuppressive effect against Plasmodium berghei yoelii and Plasmodium berghei berghei, while 1 had the same effect against P. berghei yoelii only. Compounds 3 and 4 did not show activity in this in vivo test system.
-
new alkaloids from Cryptolepis sanguinolenta
Tetrahedron Letters, 1996Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, M Claeys, A J VlietinckAbstract:Neocryptolepine and biscryptolepine, two new alkaloids, were isolated from the root bark extract of the African medicinal plant, Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae), and their structures elucidated on the basis of spectral evidence. The 1H and 13C NMR assignments of cryptoquindoline, a known artefact, were revised.
-
in vitro biological activities of alkaloids from Cryptolepis sanguinolenta
Planta Medica, 1996Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, M Claeys, L Tona, K Kambu, A Lasure, Bart Van Poel, Dirk Vanden Berghe, A J VlietinckAbstract:In our biological screening of higher plants, an aqueous and an 80% EtOH extract from the root bark of Cryptolepis sanguinolenta showed potent antibacterial, anticomplementary, and moderate antiviral activities, but no antifungal effect could be detected. Bioassay-guided fractionation of the 80% EtOH extract led to the isolation of three alkaloids: quindoline (1), hydroxycryptolepine (2), cryptolepine.HCl (3), and the corresponding base cryptolepine (4). All compounds strongly inhibited the growth of Gram-positive bacteria (MIC 500 micrograms/ml) against selected Gram-negative bacteria. They also possessed a bactericidal effect depending on the bacterial strain. Compounds 1, 2 and 3 displayed a dose-dependent inhibitory effect on the classical pathway of the complement system while compounds 2 and 3 activated the alternative pathway, except for compound 1. Compound 3 was found to possess an antiherpetic activity. Compounds 1 and 4 showed no antiviral effect, but were quite cytotoxic in the antiviral test system down to a concentration of 1 microgram/ml.
Luc Pieters - One of the best experts on this subject based on the ideXlab platform.
-
interactions of cryptolepine and neocryptolepine with unusual dna structures
Biochimie, 2003Co-Authors: Lionel Guittat, Luc Pieters, Patrizia Alberti, Frederic Rosu, Sabine Van Miert, Emilie Thetiot, Valerie Gabelica, Edwin De Pauw, Alexandre Ottaviani, Jeanfrancois RiouAbstract:Cryptolepine, the main alkaloid present in the roots of Cryptolepis sanguinolenta, presents a large spectrum of biological properties. It has been reported to behave like a DNA intercalator with a preference for GC-rich sequences. In this study, dialysis competition assay and mass spectrometry experiments were used to determine the affinity of cryptolepine and neocryptolepine for DNA structures among duplexes, triplexes, quadruplexes and single strands. Our data confirm that cryptolepine and neocryptolepine prefer GC over AT-rich duplex sequences, but also recognize triplex and quadruplex structures. These compounds are weak telomerase inhibitors and exhibit a significant preference for triplexes over quadruplexes or duplexes.
-
inhibitors of xanthine oxidase and scavengers of superoxide anions from Cryptolepis sanguinolenta lindl schlechter periplocaceae
Pharmacy and Pharmacology Communications, 2000Co-Authors: K Cimanga, Luc Pieters, L Tona, K Kambu, T De Bruyne, Sandra Apers, Paul Cos, P Bakana, D Vanden Berghe, A J VlietinckAbstract:Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae) is a medicinal plant used in some African countries against infectious and parasitic diseases. Six of its constituent alkaloids have been isolated from the root bark, identified spectroscopically as cryptoquindolinine (1), quindoline (2), neocryptolepine (3), cryptolepine (4), 11-hydroxycryptolepine (5) and biscryptolepine (6), and their interaction with the xanthine-xanthine oxidase enzyme system has been tested. Compound 5 has been shown to inhibit xanthine oxidase and act as a scavenger of superoxide anions. Alkaloids 1–4 and 6 were devoid of effect in both assays at the highest test concentration of 100 mM. These findings suggest the importance, in the manifestation of both activities, of the hydroxyl group present in 5 but not in the other alkaloids.
-
antibacterial and antifungal activities of neocryptolepine biscryptolepine and cryptoquindoline alkaloids isolated from Cryptolepis sanguinolenta
Phytomedicine, 1998Co-Authors: K Cimanga, Luc Pieters, L Tona, K Kambu, T De Bruyne, D Vanden Berghe, J Totte, A J VlietinckAbstract:From the 80% EtOH extract of Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaeae) root bark, a cryptolepine isomer named neocryptolepine, and two dimeric alkaloids named biscryptolepine and cryptoquindoline were isolated. These compounds were tested for their putative antibacterial and antifungal activities. Results have indicated that neocryptolepine showed an antibacterial activity against Gram-positive bacteria (MIC < 100 μg/ml), but was less acive against Gram-negative bacteria. It also inhibited the growth of the yeast C. albicans. Biscryptolepine exhibited only an activity against some Gram-positive bacteria (MIC = 62.5 or 31 μg/ml) while cryptoquindoline did not shown an activity against all selected microorganisms. The antibacterial activity of neocryptolepine and biscryptolepine is bacteriostatic rather than bactericidal. No antifungal activity could be observed for all alkaloids in our test system at the highest test concentration of 100 μg/ml.
-
in vitro and in vivo antiplasmodial activity of cryptolepine and related alkaloids from Cryptolepis sanguinolenta
Journal of Natural Products, 1997Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, A J Vlietinck, C A TurgerAbstract:Three different extracts and four alkaloids from the root bark of Cryptolepis sanguinolenta have been assessed in vitro against Plasmodium falciparum D-6 (chloroquine-sensitive strain), K-1, and W-2 (chloroquine-resistant strains). Cryptolepine (1) and its hydrochloride (2), 11-hydroxycryptolepine (3), and neocryptolepine (5) showed a strong antiplasmodial activity against P. falciparum chloroquine-resistant strains. Quindoline (4) was less active. The highest activity was obtained with compound 1. In vivo tests on infected mice showed that crytpolepine (1), when tested as its hydrochloride (2), exhibited a significant chemosuppressive effect against Plasmodium berghei yoelii and Plasmodium berghei berghei, while 1 had the same effect against P. berghei yoelii only. Compounds 3 and 4 did not show activity in this in vivo test system.
-
new alkaloids from Cryptolepis sanguinolenta
Tetrahedron Letters, 1996Co-Authors: K Cimanga, T De Bruyne, Luc Pieters, M Claeys, A J VlietinckAbstract:Neocryptolepine and biscryptolepine, two new alkaloids, were isolated from the root bark extract of the African medicinal plant, Cryptolepis sanguinolenta (Lindl.) Schlechter (Periplocaceae), and their structures elucidated on the basis of spectral evidence. The 1H and 13C NMR assignments of cryptoquindoline, a known artefact, were revised.