MyMedR

Jerantinines A-G, cytotoxic Aspidosperma alkaloids from Tabernaemontana corymbosa

Lim KH, Hiraku O, Komiyama K, Kam TS

J Nat Prod, 2008 Sep;71(9):1591-4.

Seven new indole alkaloids of the Aspidosperma type, jerantinines A-G (1-7), were isolated from a leaf extract of the Malayan Tabernaemontana corymbosa. The structures were established using NMR and MS analysis. Five of the alkaloids isolated and two derivatives (1-5, 8, 9) displayed pronounced in vitro cytotoxicity against human KB cells (IC50 < 1 microg/mL).

Matched MeSH terms: Indole Alkaloids/chemistry

Fulltext Grandine A, a new proaporphine alkaloid from the bark of Phoebe grandis

Mukhtar MR, Aziz AN, Thomas NF, Hadi AH, Litaudon M, Awang K

Molecules, 2009;14(3):1227-33.

PMID: 19325519 DOI: 10.3390/molecules14031227

The stem bark of Phoebe grandis afforded one new oxoproaporphine; (-)-grandine A (1), along with six known isoquinoline alkaloids: (-)-8,9-dihydrolinearisine (2), boldine, norboldine, lauformine, scortechiniine A and scortechiniine B. In addition to that of the new compound, complete 1H- and 13C-NMR data of the tetrahydroproaporphine (-)-8,9-dihydrolinearisine (2) is also reported. The alkaloids' structures were elucidated primarily by means of high field 1D- and 2D-NMR and HRMS spectral data.

Matched MeSH terms: Alkaloids/chemistry*

Leuconicines A-G and (-)-eburnamaline, biologically active strychnan and eburnan alkaloids from Leuconotis

Gan CY, Low YY, Etoh T, Hayashi M, Komiyama K, Kam TS

J Nat Prod, 2009 Dec;72(12):2098-103.

PMID: 20035556 DOI: 10.1021/np900576b

Seven new indole alkaloids of the Strychnos type, leuconicines A-G (1-7), and a new eburnan alkaloid, (-)-eburnamaline (8), were isolated from the stem-bark extract of two Malayan Leuconotis species. The structures of these alkaloids were established using NMR and MS analysis and in the case of 8 also by partial synthesis. Alkaloids 1-5 reversed multidrug resistance in vincristine-resistant KB cells.

Matched MeSH terms: Indole Alkaloids/chemistry

Fulltext Evaluation of the effects of Mitragyna speciosa alkaloid extract on cytochrome P450 enzymes using a high throughput assay

Kong WM, Chik Z, Ramachandra M, Subramaniam U, Aziddin RE, Mohamed Z

Molecules, 2011 Aug 29;16(9):7344-56.

PMID: 21876481 DOI: 10.3390/molecules16097344

The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown to be a fast and cost-effective way to perform CYP inhibition studies. The results indicated that MSE has the most potent inhibitory effect on CYP3A4 and CYP2D6, with apparent half-maximal inhibitory concentration (IC(50)) values of 0.78 µg/mL and 0.636 µg/mL, respectively. In addition, moderate inhibition was observed for CYP1A2, with an IC(50) of 39 µg/mL, and weak inhibition was detected for CYP2C19. The IC(50) of CYP2C19 could not be determined, however, because inhibition was <50%. Competitive inhibition was found for the MSE-treated CYP2D6 inhibition assay, whereas non-competitive inhibition was shown in inhibition assays using CYP3A4, CYP1A2 and CYP2C19. Quinidine (CYP2D6), ketoconazole (CYP3A4), tranylcypromine (CYP2C19) and furafylline (CYP1A2) were ACCESSused as positive controls throughout the experiments. This study shows that MSE may contribute to an herb-drug interaction if administered concomitantly with drugs that are substrates for CYP3A4, CYP2D6 and CYP1A2.

Matched MeSH terms: Alkaloids/chemistry*

Fulltext Two new acridone alkaloids from Glycosmis macrantha

Yahayu MA, Rahmani M, Hashim NM, Amin MA, Ee GC, Sukari MA, et al.

Molecules, 2011 May 27;16(6):4401-7.

PMID: 21623311 DOI: 10.3390/molecules16064401

Extraction and chromatographic separation of the extracts of dried stem barks of Glycosmis macrantha lead to isolation of two new acridone alkaloids, macranthanine and 7-hydroxynoracronycine, and a known acridone, atalaphyllidine. The structures of these alkaloids were determined by detailed spectral analysis and also by comparison with reported data.

Matched MeSH terms: Alkaloids/chemistry*

Neolamarckines A and B, new indole alkaloids from Neolamarckia cadamba

Qureshi AK, Mukhtar MR, Hirasawa Y, Hosoya T, Nugroho AE, Morita H, et al.

Chem Pharm Bull (Tokyo), 2011;59(2):291-3.

PMID: 21297315

Two new indole alkaloids, neolamarckines A and B (1, 2) were isolated from the leaves of Neolamarckia cadamba (Rubiaceae). Structural elucidation of 1 and 2 was performed by combination of 2D-NMR and circular dichroism (CD) spectra, and chemical correlations. Neolamarckine A (1) showed inhibition of inducible nitric oxide synthase (iNOS) dose dependently.

Matched MeSH terms: Indole Alkaloids/chemistry

A new amide alkaloid from the leaves of Piper sarmentosum

Sim KM, Mak CN, Ho LP

J Asian Nat Prod Res, 2009 Aug;11(8):757-60.

PMID: 20183320 DOI: 10.1080/10286020903058933

A new amide alkaloid, N-(3',4',5'-trimethoxy-cis-cinnamoyl)pyrrolidine (1), named sarmentomicine was isolated from the ethanol extract of the leaves of Malayan Piper sarmentosum, together with two known phenylpropanoids. Their structures were elucidated on the basis of spectroscopic analysis.

Matched MeSH terms: Alkaloids/chemistry

Biologically active ibogan and vallesamine derivatives from Tabernaemontana divaricata

Kam TS, Pang HS, Choo YM, Komiyama K

Chem Biodivers, 2004 Apr;1(4):646-56.

PMID: 17191876

Six new indole alkaloids, viz., (3S)-3-cyanocoronaridine (2), (3S)-3-cyanoisovoacangine (3), conolobine A (5), conolobine B (6), conolidine (7), and (3R/3S)-3-ethoxyvoacangine (8), in addition to 36 known ones, were obtained from the stem-bark extract of the Malayan Tabernaemontana divaricata. The structures were determined by NMR and MS analysis. The CN-substituted alkaloids showed appreciable cytotoxicity towards the KB human oral epidermoid carcinoma cell-line.

Matched MeSH terms: Indole Alkaloids/chemistry

Criofolinine and vernavosine, new pentacyclic indole alkaloids incorporating pyrroloazepine and pyridopyrimidine moieties derived from a common yohimbine precursor

Nge CE, Gan CY, Lim KH, Ting KN, Low YY, Kam TS

Org. Lett., 2014 Dec 19;16(24):6330-3.

PMID: 25454201 DOI: 10.1021/ol503072g

Two new indole alkaloids characterized by previously unencountered natural product skeletons, viz., criofolinine (1), incorporating a pyrroloazepine motif within a pentacyclic ring system, and vernavosine (2, isolated as its ethyl ether derivative 3, which on hydrolysis regenerated the putative precursor alkaloid 2), incorporating a pyridopyrimidine moiety embedded within a pentacyclic carbon framework, were isolated from a Malayan Tabernaemontana species. The structures and absolute configuration of these alkaloids were determined on the basis of NMR and MS analysis and confirmed by X-ray diffraction analysis.

Matched MeSH terms: Indole Alkaloids/chemistry*

Oxidized derivatives of macroline, sarpagine, and pleiocarpamine alkaloids from Alstonia angustifolia

Tan SJ, Lim JL, Low YY, Sim KS, Lim SH, Kam TS

J Nat Prod, 2014 Sep 26;77(9):2068-80.

PMID: 25211145 DOI: 10.1021/np500439u

A total of 20 new indole alkaloids comprising mainly oxidized derivatives of macroline- (including alstofonidine, a macroline indole incorporating a butyrolactone ring-F), pleiocarpamine-, and sarpagine-type alkaloids were isolated from the bark and leaf extracts of Alstonia angustifolia. The structures and relative configurations of these alkaloids were determined using NMR and MS analyses and in some instances confirmed by X-ray diffraction analyses. Alkaloids 3, 7, 35, and 41 showed moderate to weak activity, while 21 showed strong activity in reversing multidrug resistance in vincristine-resistant KB cells.

Matched MeSH terms: Indole Alkaloids/chemistry

Antibacterial alkaloids from Artabotrys crassifolius Hook.f. & Thomson

Tan KK, Khoo TJ, Rajagopal M, Wiart C

Nat Prod Res, 2015;29(24):2346-9.

PMID: 25738993 DOI: 10.1080/14786419.2015.1013954

Chloroform extract of bark of Artabotrys crassifolius Hook.f. & Thomson exhibited antibacterial activities against both American Type Culture Collection and clinical bacterial strains in vitro with zones of inhibition ranging from 7 to 14 mm. Further analysis of this extract yielded artabotrine, liridine, lysicamine and atherospermidine. Artabotrine displayed a broad array of antibacterial activity mostly against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 1.25 μg/mL to 5 μg/mL. Of note, artabotrine, liridine and lysicamine are bactericidal against Gram-negative extended-spectrum beta-lactamase-producing Klebsiella with MIC values equal 2.5, 2.5 and 10 μg/mL, respectively, and minimum bactericidal concentrations values equal to 2.5, 5 and 20 μg/mL.

Matched MeSH terms: Alkaloids/chemistry*

Fulltext Understanding the physicochemical properties of mitragynine, a principal alkaloid of Mitragyna speciosa, for preclinical evaluation

Ramanathan S, Parthasarathy S, Murugaiyah V, Magosso E, Tan SC, Mansor SM

Molecules, 2015 Mar 18;20(3):4915-27.

PMID: 25793541 DOI: 10.3390/molecules20034915

Varied pharmacological responses have been reported for mitragynine in the literature, but no supportive scientific explanations have been given for this. These studies have been undertaken without a sufficient understanding of the physicochemical properties of mitragynine. In this work a UV spectrophotometer approach and HPLC-UV method were employed to ascertain the physicochemical properties of mitragynine. The pKa of mitragynine measured by conventional UV (8.11 ± 0.11) was in agreement with the microplate reader determination (8.08 ± 0.04). Mitragynine is a lipophilic alkaloid, as indicated by a logP value of 1.73. Mitragynine had poor solubility in water and basic media, and conversely in acidic environments, but it is acid labile. In an in vitro dissolution the total drug release was higher for the simulated gastric fluid but was prolonged and incomplete for the simulated intestinal fluid. The hydrophobicity, poor water solubility, high variability of drug release in simulated biological fluids and acid degradable characteristics of mitragynine probably explain the large variability of its pharmacological responses reported in the literature. The determined physicochemical properties of mitragynine will provide a basis for developing a suitable formulation to further improve its solubility, stability and oral absorption for better assessment of this compound in preclinical studies.

Matched MeSH terms: Secologanin Tryptamine Alkaloids/chemistry*

Alkaloids from the roots of Stichoneuron caudatum and their acetylcholinesterase inhibitory activities

Ramli RA, Lie W, Pyne SG

J Nat Prod, 2014 Apr 25;77(4):894-901.

PMID: 24606395 DOI: 10.1021/np400978x

Four new stichoneurine-type alkaloids, stichoneurines F and G (1-2) and sessilistemonamines E and F (3-4), have been isolated from the root extracts of Stichoneuron caudatum. The structures and relative configurations of these alkaloids have been determined by spectroscopic methods and molecular modeling experiments. Compounds 1-4 were tested for their acetylcholinesterase (AChE) inhibitory activities against human AChE. Compound 3 showed significant inhibitory activity with an IC50 value of 9.1±0.15 μM.

Matched MeSH terms: Alkaloids/chemistry

Fulltext Anticholinesterase inhibitory activity of quaternary alkaloids from Tinospora crispa

Yusoff M, Hamid H, Houghton P

Molecules, 2014 Jan 20;19(1):1201-11.

PMID: 24448061 DOI: 10.3390/molecules19011201

Quaternary alkaloids are the major alkaloids isolated from Tinospora species. A previous study pointed to the necessary presence of quaternary nitrogens for strong acetylcholinesterase (AChE) inhibitory activity in such alkaloids. Repeated column chromatography of the vine of Tinospora crispa extract led to the isolation of one new protoberberine alkaloid, 4,13-dihydroxy-2,8,9-trimethoxydibenzo[a,g]quinolizinium (1), along with six known alkaloids-dihydrodiscretamine (2), columbamine (3), magnoflorine (4), N-formylannonaine (5), N-formylnornuciferine (6), and N-trans-feruloyltyramine (7). The seven compounds were isolated and structurally elucidated by spectroscopic analysis. Two known alkaloids, namely, dihydrodiscretamine and columbamine are reported for the first time for this plant. The compounds were tested for AChE inhibitory activity using Ellman's method. In the AChE inhibition assay, only columbamine (3) showed strong activity with IC50 48.1 µM. The structure-activity relationships derived from these results suggest that the quaternary nitrogen in the skeleton has some effect, but that a high degree of methoxylation is more important for acetylcholinesterase inhibition.

Matched MeSH terms: Berberine Alkaloids/chemistry

Transformations of the 2,7-Seco Aspidosperma alkaloid leuconolam, structure revision of epi-leuconolam, and partial syntheses of leuconoxine and leuconodines A and F

Low YY, Hong FJ, Lim KH, Thomas NF, Kam TS

J Nat Prod, 2014 Feb 28;77(2):327-38.

PMID: 24428198 DOI: 10.1021/np400922x

Several transformations of the seco Aspidosperma alkaloid leuconolam were carried out. The based-induced reaction resulted in cyclization to yield two epimers, the major product corresponding to the optical antipode of a (+)-meloscine derivative. The structures and relative configuration of the products were confirmed by X-ray diffraction analysis. Reaction of leuconolam and epi-leuconolam with various acids, molecular bromine, and hydrogen gave results that indicated that the structure of the alkaloid, previously assigned as epi-leuconolam, was incorrect. This was confirmed by an X-ray diffraction analysis, which revealed that epi-leuconolam is in fact 6,7-dehydroleuconoxine. Short partial syntheses of the diazaspiro indole alkaloid leuconoxine and the new leuconoxine-type alkaloids leuconodines A and F were carried out.

Matched MeSH terms: Indole Alkaloids/chemistry*

Total Synthesis of (-)-Conolutinine

Feng X, Jiang G, Xia Z, Hu J, Wan X, Gao JM, et al.

Org. Lett., 2015 Sep 18;17(18):4428-31.

PMID: 26315849 DOI: 10.1021/acs.orglett.5b02046

The first enantioselective synthesis of (-)-conolutinine was achieved in 10 steps. The synthesis featured a catalytic asymmetric bromocyclization of tryptamine to forge the tricycle intermediate. Hydration of an alkene catalyzed by Co(acac)2 was also employed as a key step to diastereoselectively introduce the tertiary alcohol moiety. The absolute configuration of (-)-conolutinine was established to be (2S,5aS,8aS,13aR) based on this asymmetric total synthesis.

Matched MeSH terms: Indole Alkaloids/chemistry

Fulltext Natural Bioactive Molecules: An Alternative Approach to the Treatment and Control of COVID-19

Islam F, Bibi S, Meem AFK, Islam MM, Rahaman MS, Bepary S, et al.

Int J Mol Sci, 2021 Nov 23;22(23).

PMID: 34884440 DOI: 10.3390/ijms222312638

Several coronaviruses (CoVs) have been associated with serious health hazards in recent decades, resulting in the deaths of thousands around the globe. The recent coronavirus pandemic has emphasized the importance of discovering novel and effective antiviral medicines as quickly as possible to prevent more loss of human lives. Positive-sense RNA viruses with group spikes protruding from their surfaces and an abnormally large RNA genome enclose CoVs. CoVs have already been related to a range of respiratory infectious diseases possibly fatal to humans, such as MERS, SARS, and the current COVID-19 outbreak. As a result, effective prevention, treatment, and medications against human coronavirus (HCoV) is urgently needed. In recent years, many natural substances have been discovered with a variety of biological significance, including antiviral properties. Throughout this work, we reviewed a wide range of natural substances that interrupt the life cycles for MERS and SARS, as well as their potential application in the treatment of COVID-19.

Matched MeSH terms: Alkaloids/chemistry

Fulltext Manzamine A: A promising marine-derived cancer therapeutic for multi-targeted interactions with E2F8, SIX1, AR, GSK-3β, and V-ATPase - A systematic review

Mishan MA, Choo YM, Winkler J, Hamann MT, Karan D

Eur J Pharmacol, 2025 Mar 05;990:177295.

PMID: 39863145 DOI: 10.1016/j.ejphar.2025.177295

Manzamine A, a natural compound derived from various sponge genera, features a β-carboline structure and exhibits a range of biological activities, including anti-inflammatory and antimalarial effects. Its potential as an anticancer agent has been explored in several tumor models, both in vitro and in vivo, showing effects through mechanisms such as cytotoxicity, regulation of the cell cycle, inhibition of cell migration, epithelial-to-mesenchymal transition (EMT), autophagy, and apoptosis through multi-target interactions of E2F transcriptional factors, ribosomal S6 kinases, androgen receptor (AR), SIX1, GSK-3β, v-ATPase, and p53/p21/p27 cascades. This systematic review evaluates existing literature on the potential application of this marine alkaloid as a novel cancer therapy, highlighting its promising ability to inhibit cancer cell growth while causing minimal side effects.

Matched MeSH terms: Indole Alkaloids/chemistry

Angustilobine and andranginine type indole alkaloids and an uleine-secovallesamine bisindole alkaloid from Alstonia angustiloba

Ku WF, Tan SJ, Low YY, Komiyama K, Kam TS

Phytochemistry, 2011 Dec;72(17):2212-8.

PMID: 21889176 DOI: 10.1016/j.phytochem.2011.08.001

A total of 20 alkaloids were isolated from the leaf and stem-bark extracts of Alstonia angustiloba, of which two are hitherto unknown. One is an alkaloid of the angustilobine type (angustilobine C), while the other is a bisindole alkaloid angustiphylline, derived from the union of uleine and secovallesamine moieties. The structures of these alkaloids were established using NMR and MS analysis. Angustilobine C showed moderate cytotoxicity towards KB cells.

Matched MeSH terms: Alkaloids/chemistry; Indole Alkaloids/chemistry

Fulltext Antifungal Activity of Aqueous Extracts of Some Dominant Algerian Medicinal Plants

Salhi N, Mohammed Saghir SA, Terzi V, Brahmi I, Ghedairi N, Bissati S

Biomed Res Int, 2017;2017:7526291.

PMID: 29226147 DOI: 10.1155/2017/7526291

Aim: This study investigated the antifungal properties of aqueous extracts obtained from indigenous plants that grow spontaneously in the Northern Sahara of Algeria. The activities of these plants in controlling two fungal species that belong to Fusarium genus were evaluated in an in vitro assay.

Materials and Methods: Fresh aerial parts of four plant species (Artemisia herba alba, Cotula cinerea, Asphodelus tenuifolius, and Euphorbia guyoniana) were collected for the preparation of aqueous extracts. Two levels of dilution (10% and 20%) of the pure extracts were evaluated against Fusarium graminearum and Fusarium sporotrichioides.

Results: The results of this study revealed that the A. herba alba, C. cinerea, A. tenuifolius, and E. guyoniana aqueous extracts are effective at both concentrations of 10% and 20% for the Fusarium mycelia growth inhibition. In particular, A. tenuifolius extract is effective against F. graminearum, whereas F. sporotrichioides mycelium growth is strongly affected by the E. guyoniana 20% extract. The phytochemical characterization of the compositions of the aqueous extracts has revealed that the presence of some chemical compounds (tannins, flavonoids, saponins, steroids, and alkaloids) is likely to be responsible for the antifungal activities sought.

Conclusion: The antifungal properties of A. herba alba, C. cinerea, A. tenuifolius, and E. guyoniana make these plants of potential interest for the control of fungi affecting both wheat yield and safety.

Matched MeSH terms: Alkaloids/chemistry

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