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Kgakatsi NA, Majinda RRT, Masesane IB, Nwamadi MS, Demissie TB, Ombito JO, Gobe I. New isoflavan from Erythrina livingstoniana. Nat Prod Res 2024; 38:493-502. [PMID: 36190792 DOI: 10.1080/14786419.2022.2130300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/21/2022] [Indexed: 10/10/2022]
Abstract
Chemical investigation of the root wood of Erythrina livingstoniana led to the isolation of one previously undescribed isoflavan (3S,3″R)-7-hydroxy-2'-methoxy-[3″-hydroxy-2″,2″-dimethylpyrano (3',4')] isoflavan 1, together with eleven known compounds 2-12. The structure of compound 1 was elucidated on the basis of extensive spectroscopic and spectrometric analyses (1 D and 2 D-NMR and APCI-HRMS), with absolute configurations established by comparison of experimental and DFT calculated ECD data. The assignment of the absolute configurations of C-3 and C-3″ of compounds 2 and 3, respectively, were reported for the first time. Compounds 1 - 4 were evaluated for their antibacterial activities in vitro against E. coli ATCC 25922 and S. aureus ATCC 25923. Compound 1 exhibited moderate antibacterial activity with MIC value of 0.063 mg/mL against the clinically relevant risk-group 2 (RG-2) bacterium S. aureus.
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Affiliation(s)
- Nayang A Kgakatsi
- Department of Chemistry, University of Botswana, Gaborone, Botswana
- Boitekanelo College, Gaborone, Botswana
| | | | | | | | - Taye B Demissie
- Department of Chemistry, University of Botswana, Gaborone, Botswana
| | - Japheth O Ombito
- Department of Chemistry, University of Botswana, Gaborone, Botswana
| | - Irene Gobe
- Department of Medical Laboratory Science, University of Botswana, Gaborone, Botswana
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2
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Kgakatsi NA, Majinda RRT, Masesane IB, Gobe I. Methoxylated bibenzyls and isoflavones from Baphia massaiensis Taub. Nat Prod Res 2023:1-7. [PMID: 36995029 DOI: 10.1080/14786419.2023.2196076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Chemical investigation of the stem bark of Baphia massaiensis Taub. led to the isolation of two new natural compounds named 3-hydroxy-2,5,2'-trimethoxybibenzyl (1) and 2'-hydroxy-2,3,5,6-tetramethoxybibenzyl (2), the latter has been previously reported as a synthetic compound, together with twelve known compounds 3-14. The chemical structures of the isolated compounds were elucidated by using NMR analysis and mass spectrometry, as well as comparisons with the reported data in the literature. Known bibenzyls 3-5, bauhinoxepin J (6), and isoflavones 7-10 and 12-14, were reported from genus Baphia for the first time. The isolated compounds were evaluated for their antibacterial activities in-vitro against Staphylococcus aureus and Escherichia coli. The bioactivity evaluation revealed that bibenzyls 1 and 2 showed weak inhibitory activity with MIC values of 1000 µg/mL against S. aureus and bauhinoxepin J (6) showed moderate inhibitory activity with MIC value of 63 µg/mL against S. aureus.
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Affiliation(s)
- Nayang A Kgakatsi
- Department of Chemistry, University of Botswana, Gaborone, Botswana
- Boitekanelo College, Gaborone, Botswana
| | | | | | - Irene Gobe
- Department of Medical Laboratory Science, University of Botswana, Gaborone, Botswana
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Majinda RRT, Masesane IB, Singh GS. An account of organic chemistry research in Botswana. ARKIVOC 2022. [DOI: 10.24820/ark.5550190.p011.780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kgakatsi N, Majinda RRT, Masesane IB. BF3OEt2 and MeSO3H-Promoted reactions of phenols and ethyl phenylpropiolate as a synthetic routes to neoflavones and a potential route to flavones. ARKIVOC 2022. [DOI: 10.24820/ark.5550190.p011.774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
Abstract
The molecular structures of 3 isoflavone glycosides isolated from the root wood of Erythrina latissimawere established as 4′-hydroxyisoflavone-7-O-β-D-glucopyranoside (compound 1); 4′-hydroxyisoflavone-7-O-α-L-rhamnosyl (1→6)-β-D-glucopyranoside (compound 2); and a new compound 4′, 8-dimethoxy isoflavone-7-O-α-L-rhamnosyl(1→6)-β-D-glucopyranoside (8-O-methylretusin-7-O-α-L-rhamnosyl (1→6)-β-D-glucopyranoside) (compound 3).
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Affiliation(s)
- Cornelius C W Wanjala
- University of Botswana, Department of Chemistry, Private Bag 00704, Gaborone, Botswana
| | - Runner R T Majinda
- University of Botswana, Department of Chemistry, Private Bag 00704, Gaborone, Botswana
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Abstract
Phytochemical analysis of twigs and roots of Erythrina abyssinica, a traditionally used medicinal plant, gave a new radical scavenging flavanone, 7,3′,4′-trihydroxy-5′-prenylflavanone (abyssinone VII; 1), along with twenty-one known compounds, whose radical scavenging and antimicrobial activities were also assessed.
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Affiliation(s)
- Francis Machumi
- Department of Chemistry, University of Botswana, Private Bag UB 00704 Gaborone, Botswana
| | | | - Renameditswe Mapitse
- Department of Chemistry, University of Botswana, Private Bag UB 00704 Gaborone, Botswana
| | - Ishmael Masesane
- Department of Chemistry, University of Botswana, Private Bag UB 00704 Gaborone, Botswana
| | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag UB 00704 Gaborone, Botswana
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Ajayi OS, Aderogba MA, Obuotor EM, Majinda RRT. Acetylcholinesterase inhibitor from Anthocleista vogelii leaf extracts. J Ethnopharmacol 2019; 231:503-506. [PMID: 30415061 DOI: 10.1016/j.jep.2018.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Anthocleista vogelii (Planch) is used in folk medicine in conditions related to inflammation and oxidative stress. This suggests that some of its constituents could possess ability to reduce oxidative damage to cells and ameliorate inflammatory conditions which are two prominent features in the brain of a person suffering from Alzheimer's disease. AIM OF STUDY The leaf extracts were investigated for their bioactive constituents in our quest for novel compounds for the management of Alzheimer's disease. MATERIALS AND METHODS Anthocleista vogelii crude leaf extract obtained from 80% methanol was successively partitioned with n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc) and n-butanol. This gave four solvent fractions of the crude extract. These fractions and isolated compound were subjected to acetylcholinesterase (AChE) inhibitory activity test using the microplate assay method. The structure of the isolated compound was determined using spectroscopic methods (1D and 2D NMR, and MS). RESULTS The results of the acetylcholinesterase inhibitory assay revealed that n-BuOH and ethyl acetate fractions had the best activity with IC50 of 564.58 and 727.63 µg/mL respectively. Activity directed fractionation of each of these fractions led to the isolation of the same compound identified as a C-glucosylflavone; isovitexin-7-O-methyl ether (swertisin). This rare C-glucosylflavone co-exist as two rotamers and exhibited duplication of NMR signals. It is reported from this plant for the first time. Swertisin displayed better acetylcholinesterase inhibitory activity with IC50 of 32.09 µg/mL than physostigmine (eserine) with IC50 of 56.09 µg/mL used as a standard. CONCLUSIONS This study reports isolation and characterization of a rare C-glycosylflavone; isovitexin-7-O-methyl ether (swertisin). Isolated compound exhibited duplication of NMR signals and better acetylcholinesterase inhibitory activity than eserine used as a standard. The activity exhibited by this compound suggests that it could be useful in the management of Alzheimer's disease.
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Affiliation(s)
- O S Ajayi
- Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria; Department of Chemistry, University of Botswana, Gaborone, Botswana
| | - M A Aderogba
- Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria.
| | - E M Obuotor
- Department of Biochemistry, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - R R T Majinda
- Department of Chemistry, University of Botswana, Gaborone, Botswana
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Keroletswe N, Majinda RRT, Masesane IB. A New 3-Prenyl-2-flavene and Other Extractives from Baphia massaiensis and Their Antimicrobial Activities. Nat Prod Commun 2018. [DOI: 10.1177/1934578x1801300414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
One new 3-prenyl-2-flavene, named baphiflavene A, 1, and eleven known compounds, 2-12, were isolated and reported for the first time from Baphia massaiensis using several chromatographic techniques. Their structures were elucidated using different spectroscopic techniques; 1D and 2D-NMR, HRMS, GC-MS, UV/Vis, FTIR and by comparison with literature data. The isolates were tested against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans to establish their preliminary antimicrobial activities. The results revealed that compound 1 had moderate activities against both Gram positive ( B. subtilis and S. aureus) and Gram negative ( E. coli and P. aeruginosa) bacteria, and good activity against C. albicans with inhibition zones of 10–23 mm (compared to 19 mm for chloramphenicol and miconazole standards). To the best of our knowledge, this is the first phytochemical work reported on Baphia massaiensis.
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Affiliation(s)
- Ngonye Keroletswe
- Department of Chemistry, University of Botswana, Private Bag 0022, Gaborone, Botswana
- Botswana Institute for Technology Research and Innovation, Private Bag 0082, Gaborone, Botswana
| | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag 0022, Gaborone, Botswana
| | - Ishmael B. Masesane
- Department of Chemistry, University of Botswana, Private Bag 0022, Gaborone, Botswana
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Abstract
The period of the past 5 years has witnessed a remarkable increase in all of the number, structural variety, and complexity of erythrinan alkaloids reported. This structural diversity seems to be most pronounced in the alkaloids reported from the two species Erythrina arborescens and Erythrina variegata. Between them, work-up of these taxa yielded new polymeric (dimeric and trimeric) erythrinan alkaloids, a first example in one case where a normal 6,5,6,6-membered indoloisoquinoline spirocylic core has rearranged to a spiro-fused 6,5,7,6-skeleton. Furthermore, erythrinan alkaloids with a fifth ring containing a 2H-imidazole functionality were also reported for the first time, together with some new structures having an unusual substitution and with functionalities at positions C-3 and C-7 of the erythrinan core. This contribution has included 40 more erythrinan alkaloids that are either new or were omitted in the most recent major reviews on the same topic, leading to a total of 154 known erythrinan alkaloids to date. There are a few cases where the structures of the new alkaloids are contestable due to insufficient data having been obtained on isolation. To facilitate easier reference and identification, all structures having a common core have been placed in the same table or figure in this chapter.The reported pharmacological activities of the new and known erythrinan alkaloids documented have shown a considerable bias towards central nervous system and related activities. Other prominent activities that have been reported are antifeedant, insecticidal, cytotoxic, antiprotozoal, anti-inflammatory, antioxidant, antifungal, and antiviral effects. Erythrinan alkaloids generally seem to lack antibacterial activity. Several new polymeric alkaloids were found to lack cytotoxicity against a number of human cancer cell lines, although two of them showed moderate aphicidal activity and one exhibited weak to moderate acetylcholinesterase inhibition. The biological activity of erythrinan alkaloids seems to be influenced by basic substructural requirements, such as a conjugated diene (Δ1,2, Δ6,7) system and is modulated by the presence (or absence) of other groups in rings A, B, C, and D of the erythrinan core. The erythrinan core may provide potential leads to structures that eventually may be useful therapeutically.In recent years, a number of stereoselective chemical synthesis methods have been applied towards the erythinan alkaloids, and these are described in this contribution.
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Abosl AO, Mbukwa E, Majinda RRT, Raserok BH, Yenesew A, Midiwo JO, Akala H, Liyala P, Waters NC. Vangueria infausta root bark: in vivo and in vitro antiplasmodial activity. Br J Biomed Sci 2016; 63:129-33. [PMID: 17058713 DOI: 10.1080/09674845.2006.11732732] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Vangueria infausta burch subsp. infausta (Rubiaceae) produces fruits eaten by humans and animals. The leaf, fruit, stem bark and root bark are used as a remedy for many ailments and the roots are used to treat malaria. In this study, concentrations of fractions of the V. infausta root bark extract that produce 50% inhibition (IC50) are determined using the ability of the extract to inhibit the uptake of [G3H]-hypoxanthine by P. falciparum cultured in vitro. The root bark extract showed antimalarial activity against Plasmodium berghei in mice. It gave a parasite suppression of 73.5% in early infection and a repository effect of 88.7%. One fraction obtained from a chloroform extract gave an IC50 value of 3.8 +/- 1.5 microg/mL and 4.5 +/- 2.3 microg/mL against D6 and W2 strains of P. falciparum, respectively, and another from the butanol extract gave an IC50 value of 3.9 +/- 0.3 microg/mL against the D6 strain. Chloroquine had an IC50 value of 0.016 microg/mL and 0.029 microg/mL against D6 and W2 strains, respectively. The plant showed the presence of flavonoids, coumarins, tannins, terpenoids, anthraquinones and saponins.
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Affiliation(s)
- A O Abosl
- Department of Biological Sciences, University of Botswana, Gaborone, Botswana.
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Abubakar MN, Majinda RRT. GC-MS Analysis and Preliminary Antimicrobial Activity of Albizia adianthifolia (Schumach) and Pterocarpus angolensis (DC). Medicines (Basel) 2016; 3:medicines3010003. [PMID: 28930113 PMCID: PMC5456228 DOI: 10.3390/medicines3010003] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 11/16/2022]
Abstract
The non-polar components of two leguminoceae species Albizia adianthifolia (Schumach), and Pterocarpus angolensis (DC) were investigated. GC-MS analysis of the crude n-hexane and chloroform extracts together with several chromatographic separation techniques led to the identification and characterization (using NMR) of sixteen known compounds from the heartwood and stem bark of Albizia adianthifolia and Pterocarpus angolensis respectively. These constituents include, n-hexadecanoic acid (palmitic acid) 1, oleic acid 2, chondrillasterol 3, stigmasterol 4, 24S 5α-stigmast-7-en-3β-ol 5, 9,12-octadecadienoic acid (Z,Z)-, methyl ester 6, trans-13-octadecanoic acid, methyl ester 7, tetradecanoic acid 8, hexadecanoic acid, methyl ester 9, octadecanoic acid 10, tetratriacontane 11, 7-dehydrodiosgenin 12, lupeol 13, stigmasta-3,5-diene-7-one 14, friedelan-3-one (friedelin) 15, and 1-octacosanol 16. Using agar over lay method, the preliminary antimicrobial assay for the extracts was carried out against bacterial (E. coli, P. aeruginosa, B. subtilis, S. aueus) and a fungus/yeast (C. albicans) strains. The n-hexane and chloroform extracts of A. adianthifolia showed the best activity against E. coli with minimum inhibition quantity (MIQ) of 1 µg each while the remaining exhibited moderate-to-weak activity against the test microorganisms.
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Affiliation(s)
- Mustapha N Abubakar
- Chemistry Department, University of Botswana, P/Bag 0022, Gaborone, Botswana.
| | - Runner R T Majinda
- Chemistry Department, University of Botswana, P/Bag 0022, Gaborone, Botswana.
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Desta ZY, Majinda RRT. Three New Isoflavonoids from Erythrina caffra. Nat Prod Commun 2014. [DOI: 10.1177/1934578x1400900622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Three new isoflavonoids, 5,7-dihydroxy-2′,4′-dimethoxy-5′-(3-methylbut-2-enyl) isoflavanone (erycaffra A) (1), 5,7-dihydroxy-2′,4′-dimethoxy-5′-(2-hydroxy-3-methylbut-3-enyl)isoflavanone (erycaffra B) (2), and 5,7-dihydroxy-6,8-di-(2-hydroxy-3-methylbut-3-enyl)isoflavone (erycaffra C) (3), were isolated from the stem bark of E. caffra Thunb., along with eight known compounds, namely, alpinumisoflavone (4), isoerysenegalensein E (5), β-amyrin (6), oleanolic acid (7), octacosyl- E-ferulate (8), triacontyl-4-hydroxycinnamate (9), n-tetracosyl p-coumarate (10) and octacosan-1-ol (11). The structures were determined on the basis of spectroscopic (1D, 2D-NMR) and MS data and by comparison with literature values.
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Affiliation(s)
| | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag 0022, Gaborone, Botswana
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Desta ZY, Majinda RRT. Three new isoflavonoids from Erythrina caffra. Nat Prod Commun 2014; 9:817-820. [PMID: 25115087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
Three new isoflavonoids, 5,7-dihydroxy-2',4'-dimethoxy-5'-(3-methylbut-2-enyl) isoflavanone (erycaffra A) (1), 5,7-dihydroxy-2',4'-dimethoxy-5'-(2-hydroxy-3-methylbut-3-enyl)isoflavanone (erycaffra B) (2), and 5,7-dihydroxy-6,8-di-(2-hydroxy-3-methylbut-3-enyl)isoflavone (erycaffra C) (3), were isolated from the stem bark of E. caffra Thunb., along with eight known compounds, namely, alpinumisoflavone (4), isoerysenegalensein E (5), beta-amyrin (6), oleanolic acid (7), octacosyl-E-ferulate (8), triacontyl-4-hydroxycinnamate (9), n-tetracosyl p-coumarate (10) and octacosan-1-ol (11). The structures were determined on the basis of spectroscopic (1D, 2D-NMR) and MS data and by comparison with literature values.
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Yeboah EMO, Majinda RRT, Kadziola A, Muller A. Dihydro-beta-agarofuran sesquiterpenes and pentacyclic triterpenoids from the root bark of Osyris lanceolata. J Nat Prod 2010; 73:1151-1155. [PMID: 20499922 DOI: 10.1021/np900597w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Three new dihydro-beta-agarofuran polyesters, 1alpha,9beta-difuranoyloxy-2-oxodihydro-beta-agarofuran (1), 1alpha,9beta-difuranoyloxy-2-oxo-3-enedihydro-beta-agarofuran (2), and 1alpha,9beta-difuranoyloxydihydro-beta-agarofuran (3), have been isolated from the CHCl(3) extract of the root bark of Osyris lanceolata, together with two known pentacylic triterpenoids, 4 and 5. Compounds 1-5 did not scavenge the DPPH radical within 30 min of reaction time. All five compounds displayed antifungal activity against Candida albicans. Compounds 1, 3, 4, and 5 showed antibacterial activity against the Gram-positive Bacillus subtilis and Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa, with 4 and 5 being the most active. Compound 2 displayed weak antibacterial activity only against Escherichia coli.
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Yeboah EMO, Majinda RRT. Radical Scavenging Activity and Total Phenolic Content of Extracts of the Root Bark of Osyris Lanceolata. Nat Prod Commun 2009. [DOI: 10.1177/1934578x0900400120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The root bark of Osyris lanceolata was screened for its antioxidant potential using three variations of the DPPH radical scavenging method viz a TLC-autographic assay, a semi-quantitative TLC assay, and a spectrophotometric assay. The total phenolic content was evaluated as gallic acid equivalents (GAE) using the Folin-Ciocalteu method. The powdered root bark was extracted sequentially with n-hexane, chloroform, methanol and 90% methanol/water. A separate supercritical fluid extraction (SFE) of the root bark was also carried out. The radical scavenging ability, as measured by IC50 values, was found to be 48.4 ± 0.4 and 49.5 ± 1.9 μg/mL for the 90% methanol/water and methanol extracts respectively, while those of the chloroform, n-hexane, and SFE extracts were found to be < 250 μg/mL. Under the same conditions, the values for the standards, ascorbic acid and gallic acid, were found to be 38.70 ± 0.08 and 2.86 ± 0.01 μg/mL respectively. The radical scavenging power of the five extracts correlated positively with the total phenolic content and was ranked in the following decreasing order: 90% methanol/water > methanol > chloroform > SFE > n-hexane with total phenolic contents of 290.2 ± 3.3, 271.0 ± 3.7, 74.4 ± 0.8, 62.5 ± 0.4 and 49.5 ± 1.9 mg GAE/g of dry extract, respectively. The 90% methanol/water and methanol extracts showed several components with high antioxidant activity displaying fast kinetics in both TLC assays, while the chloroform, SFE, and n-hexane extracts exhibited slow kinetics antioxidant activity.
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Affiliation(s)
- Elizabeth M. O. Yeboah
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
| | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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Yeboah EMO, Majinda RRT. Radical scavenging activity and total phenolic content of extracts of the root bark of Osyris lanceolata. Nat Prod Commun 2009; 4:89-94. [PMID: 19370882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
The root bark of Osyris lanceolata was screened for its antioxidant potential using three variations of the DPPH radical scavenging method viz a TLC-autographic assay, a semi-quantitative TLC assay, and a spectrophotometric assay. The total phenolic content was evaluated as gallic acid equivalents (GAE) using the Folin-Ciocalteu method. The powdered root bark was extracted sequentially with n-hexane, chloroform, methanol and 90% methanol/water. A separate supercritical fluid extraction (SFE) of the root bark was also carried out. The radical scavenging ability, as measured by IC50 values, was found to be 48.4 +/- 0.4 and 49.5 +/- 1.9 microg/mL for the 90% methanol/water and methanol extracts respectively, while those of the chloroform, n-hexane, and SFE extracts were found to be > 250 microg/mL. Under the same conditions, the values for the standards, ascorbic acid and gallic acid, were found to be 38.70 +/- 0.08 and 2.86 +/- 0.01 microg/mL respectively. The radical scavenging power of the five extracts correlated positively with the total phenolic content and was ranked in the following decreasing order: 90% methanol/water > methanol > chloroform > SFE > n-hexane with total phenolic contents of 290.2 +/- 3.3, 271.0 +/- 3.7, 74.4 +/- 0.8, 62.5 +/- 0.4 and 49.5 +/- 1.9 mg GAE/g of dry extract, respectively. The 90% methanol/water and methanol extracts showed several components with high antioxidant activity displaying fast kinetics in both TLC assays, while the chloroform, SFE, and n-hexane extracts exhibited slow kinetics antioxidant activity.
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Affiliation(s)
- Elizabeth M O Yeboah
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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Nazemiyeh H, Bahadori F, Delazar A, Ay M, Topçu G, Nahar L, Majinda RRT, Sarker SD. Antioxidant phenolic compounds from the leaves of Erica Arborea (Ericaceae). Nat Prod Res 2008; 22:1385-92. [PMID: 19023799 DOI: 10.1080/14786410701824007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Reversed-phase HPLC analyses of the methanol extract of the leaves of Erica arborea afforded a novel phenylpropanoid glucoside, named ericarborin, together with five flavonoids, dihydromyricetin 3-O-alpha-L-rhamnopyranoside, quercetin 3-O-beta-D-glucopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside, apigenin 7-O-beta-D-glucopyranoside and apigenin 7-O-beta-D-(6-O-acetyl-glucopyranoside). While the structure of ericarborin was determined by extensive 1D and 2D NMR analyses, the structures of all known flavonoids were determined by direct comparison of their spectroscopic data with respective literature data. The antioxidant properties of these compounds were assessed by the DPPH assay. The chemotaxonomic significance of these phenolic compounds has been discussed.
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Affiliation(s)
- Hossein Nazemiyeh
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
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Abstract
Investigation of the roots of Ceriops tagal led to the isolation of a new isopimarane, together with the known diterpenes isopimar-8(14)-en-15,16-diol and erythroxyl-4(17),15(16)-dien-3-one. The structure of the new compound was identified as isopimar-8(14)-en-16-hydroxy-15-one. These structures were determined from extensive spectroscopic data analysis. The isolates were screened for antibacterial activity using the agar dilution method against ten test bacterial strains ( Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Micrococcus kristinae, Pseudomonas aeruginosa, Salmonella pooni, Serratia marcescens, Staphylococcus aureus, S. epidermidis and Streptococcus pyrogens). Isopimar-8(14)-en-16-hydroxy-15-one exhibited activity, with MIC values of 0.5 mg/mL against Streptococcus pyrogens; 0.25 mg/mL against Salmonella pooni and 0.1 mg/mL against Bacillus cereus, Staphylococcus aureus and Micrococcus kristinae.
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Affiliation(s)
- Musa Chacha
- Department of Chemistry, University of Botswana, Private Bag UB 0070, Gaborone, Botswana
| | - Renameditswe Mapitse
- Department of Chemistry, University of Botswana, Private Bag UB 0070, Gaborone, Botswana
| | | | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag UB 0070, Gaborone, Botswana
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20
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B. Masesane I, N. Bwire R, R. T. Majinda R. FACILE ENANTIOSELECTIVE PALLADIUM CATALYSED TRANSFER HYDROGENATION OF α-METHYLCINNAMIC ACID IN THE PRESENCE OF OPTICAL PURE ORGANIC ACIDS. B CHEM SOC ETHIOPIA 2007. [DOI: 10.4314/bcse.v21i3.21229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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21
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Abstract
The seeds and the pulp of Gardenia volkensii yielded one new iridiod, namely 4-(2N-gardenamide)n-butanoic acid, together with the known iridoids genipin and genipin gentiobioside, the pterocarpin medicarpin, coumarins, phenylpropanoids, benzenoids and triterpenes. The structures of these were determined on the basis of spectroscopic data and by comparison of obtained data with those from literature. The fruit extracts of this plant exhibited moderate radical scavenging activity against DPPH radical and moderate lethality against brine shrimps (Artemia salina).
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Affiliation(s)
- Bernard F Juma
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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22
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Mbukwa E, Chacha M, Majinda RRT. Phytochemical constituents of Vangueria infausta: their radical scavenging and antimicrobial activities. ARKIVOC 2006. [DOI: 10.3998/ark.5550190.0008.912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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23
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Delazar A, Modarresi M, Shoeb M, Nahar L, Reid RG, Kumarasamy Y, Majinda RRT, Sarker SD. Eremostachiin: a new furanolabdane diterpene glycoside from Eremostachys glabra. Nat Prod Res 2006; 20:167-72. [PMID: 16319011 DOI: 10.1080/13518470500047082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The reversed-phase preparative HPLC analysis of the methanol extract of the rhizomes of Eremostachys glabra (Lamiaceae) led to the isolation of two furanolabdane diterpene glycosides, phlomisoside II, and beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl ester of phlomisoic acid (named eremostachiin), the latter being a novel natural product. The structure of the new compound has been elucidated unambiguously by HRMS and a series of 1D- and 2D-NMR spectroscopic techniques. The free radical scavenging activity of these compounds was assessed using the DPPH assay.
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Affiliation(s)
- Abbas Delazar
- School of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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24
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Abstract
Three new compounds, 4′,7-dihydroxy-2″,2″-dimethylpyrano [5″,6″: 5,6]-isoflavone (1), (7 E) (8,2′)-3,7,9,5′,9′-pentahydroxy-4,4′-dimethoxyneolign-7-ene (2) and (9 E,11 Z) 14-hydroxyoctadecan-9,11-dienoic acid (3), along with other known flavonoids, benzenoids, alkaloids and phenylpropanoids were isolated from the twigs, leaves, stem bark, stem wood and flowers of Erythrina lysistemon. Their structures were established on the basis of spectroscopic evidence. Some of these compounds have shown high lethality against brine shrimps ( Artemia salina), moderate radical scavenging ability in the DPPH assay, moderate antifungal activity against Candida mycoderma, moderate activity against the Gram-positive ( Bacillus subtilis and Staphylococcus aureus) and weak activity against Gram-negative bacteria ( Escherichia coli).
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Affiliation(s)
- Benard F. Juma
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
| | - Runner R. T. Majinda
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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25
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Chacha M, Bojase-Moleta G, Majinda RRT. Antimicrobial and radical scavenging flavonoids from the stem wood of Erythrina latissima. Phytochemistry 2005; 66:99-104. [PMID: 15649516 DOI: 10.1016/j.phytochem.2004.10.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Revised: 10/08/2004] [Indexed: 05/24/2023]
Abstract
From the stem wood of Erythrina latissima, two isoflavones and a flavanone were isolated and characterized as 7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)isoflavone (erylatissin A), 7,3'-dihydroxy-6'',6''-dimethyl-4'',5''-dehydropyrano [2'',3'': 4',5']isoflavone (erylatissin B), (-)-7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)flavanone (erylatissin C), respectively, in addition to 10 known flavonoids. Structures of these compounds were determined on the basis of their spectroscopic data. These compounds showed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida mycoderma. The isolated compounds also exhibited weak radical scavenging properties towards DPPH radical.
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Affiliation(s)
- Musa Chacha
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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26
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Juma BF, Majinda RRT. Erythrinaline alkaloids from the flowers and pods of Erythrina lysistemon and their DPPH radical scavenging properties. Phytochemistry 2004; 65:1397-1404. [PMID: 15231413 DOI: 10.1016/j.phytochem.2004.04.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 04/05/2004] [Indexed: 05/24/2023]
Abstract
Fourteen different erythrinaline alkaloids have been isolated from the flowers and pods of Erythrina lysistemon with four being reported for the first time in nature and five for the first time in this species and the rest having been re-isolated. The new compounds are (+)-11beta-hydroxyerysotramidine (1), (+)-11beta-methoxyerysotramidine (2), (+)-11beta-hydroxyerysotrine N-oxide (4) and (+)-11beta-hydroxyerysotrine (8). (+)-11alpha-Hydroxyerysotrine N-oxide (3), earlier misidentified as erythrartine N-oxide (beta-hydroxyerysotrine N-oxide 4), was also re-isolated along with four other alkaloids. Correct identification of compounds 4 and 8 was aided by the fact that the two sets of C-11 epimers 3, 4 and 8, 9 were both isolated in this study thus making it easier to identify and assign the individual epimers. (+)-Erythristemine (14) was found distributed in most of the plant parts investigated. Preliminary work on the crude chloroform/methanol (1:1) showed moderate toxicity to brine shrimp (LC50 23 ppm) and moderate (IC50 86 microg/ml) radical scavenging properties against stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging properties of the isolated compounds were assessed using TLC autographic and spectrophotometric assays whereupon only compounds 11 (1 microg; 90 microg/ml) and 12 (0.1 microg; 160 microg/ml) showed any notable activity. It appears the two compounds are slow reacting and do not reach steady state conditions within the standard half an hour time frame but only seemed to have reached steady state conditions after 4 h.
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Affiliation(s)
- Benard F Juma
- Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
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27
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Erasto P, Bojase-Moleta G, Majinda RRT. Antimicrobial and antioxidant flavonoids from the root wood of Bolusanthus speciosus. Phytochemistry 2004; 65:875-880. [PMID: 15081287 DOI: 10.1016/j.phytochem.2004.02.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Accepted: 02/06/2004] [Indexed: 05/24/2023]
Abstract
Three new flavonoids-5,7,4'-trihydroxy-6-[1-hydroxy-2-methylbuten-2-yl]isoflavone (isogancaonin C), 7,2'-dihydroxy-4'-methoxyisoflav-3-ene (bolusanthin III), 6,6'-dihydroxy-4'-methoxy-2-arylbenzofuran (bolusanthin IV), in addition to eight known flavonoids; derrone, medicarpan, genistein, wighteone, lupiwighteone, gancaonin C, 7-hydroxy-4'-methoxyisoflavone and 7,3'-dihydroxy-4'-methoxyisoflavone were isolated from the root wood of Bolusanthus speciosus. The compounds showed strong antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida mycoderma. The isolated compounds also showed moderate to strong radical scavenging properties against DPPH radical with the highest activities shown by the 2-arylbenzofuran, the isoflav-3-ene and 7,3'-dihydroxy-4'-methoxyisoflavone in decreasing order.
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Affiliation(s)
- Paul Erasto
- Chemistry Department, University of Botswana, Private bag UB 00704, Gaborone, Botswana
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28
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Abstract
A new isoflavanone namely 3,5,7,2',4'-pentahydroxy-8,3'-di(gamma,gamma-dimethylallyl)isoflavanone (bolusanthin II) and four new pterocarpans identified as 3-hydroxy-6',6'-dimethylpyrano[2',3':1,2] [6a R,11a R]-8,9-methylenedioxypterocarpan (bolucarpan A), 3-hydroxy-6',6'-dimethyl-4',5'-dihydropyrano[2',3':1,2][6a R,11a R]- 8,9-methylenedioxypterocarpan (bolucarpan B), 3-hydroxy-9-methoxy-6',6'-dimethylpyrano-[2',3':1,2][6a R,11a R]-pterocarpan (bolucarpan C) and 3-hydroxy-9-methoxy-6',6'-dimethyl-4',5'-dihydropyrano[2',3':1,2][6a R,11a R]-pterocarpan (bolucarpan D) and three known isoflavonoids were isolated from the methanolic extracts of the root bark, while eight known isoflavonoids were isolated from the stem bark of Bolusanthus speciosus. These compounds showed antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae and Candida mycoderma using the agar overlay technique.
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Affiliation(s)
- Gomotsang Bojase
- Department of Chemistry, University of Botswana, Gaborone, Botswana
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