Andrographolide ( 1 ) a bitter, diterpenes lactone is the most biologically active constituent from Andrographis paniculata . Andrographolide showed in vitro inhibition of the growth of Ebola virus (Zaire) with EC50 activity of 10 µM which is twenty-five-fold the activity of the control Favipiravir (EC50 = 250µM) in the Crystal violet (Plaque reduction/ Neutral red (Toxicity) assay. It also showed significant activity against Dengue fever virus with EC50 value of 0.56 µg/ml in the Visual (Cytopathic effect/ Toxicity) Assay and EC50 of 0.58 µg/ml in the Neutral Red (Cytopathic effect/ Toxicity) Assay (comparable to the values obtained with 6-Azauridine as the positive control EC50 = 0.32 µg/ml and 0.38 µg/ml in the respective bioassays; and against SARS Coronavirus. Andrographolide had an EC50 of 1.2 µg/ml in the Visual (cytopathic effect/toxicity) assay and 1.1 µg/ml in the Neutral Red (cytopathic effect/toxicity) assay. The compound exerts several immunomodulatory properties. In experimental models, it effectively reduced the levels of proinflammatory cytokines such as IL-1/3, IL-6, GMCSF, and TNF-a. The compound has a good pharmacokinetics profile and relatively non-toxic even at high doses making it an experimental drug for the treatment of viral infections, with possible application in the control of the Novel Coronavirus, Covid – 19.

The antidiabetic properties of extracts of three Nigerian medicinal plants - Ocimum basilicum L. (Lamiaceae, formerly Labiatae), Phyllanthus niruri L. (Euphorbiaceae) and Viscum album L. (Viscaceae or Loranthaceae) parasitic on Psidium guajava L. (Myrtaceae) on normoglycemic and alloxan-induced diabetic rats were studied. The extracts (258.3 g, 6.89% w/w of P. niruri, 189.17 g, 6.76% w/w of V. album and 131.50 g, 6.41% w/w of O. basilicum), obtained by 48 h cold maceration in methanol: methylene chloride (1:1), were evaluated for hypoglycemic and oral glucose tolerance effects in normoglycemic rats and antihyperglycemic effect in alloxan (100 mg/kg i.p) diabetic (blood glucose level ≥ 200 mg/dl) rats. The results showed that acute oral administration of the extracts to normoglycemic rats caused a mild to moderate non-dose-related reduction in blood glucose levels. The extracts significantly (P < 0.05) suppressed the acute postprandial rise in blood glucose to varying extents. Extract of O. basilicum lowered the elevated glucose level to 13.67% at 180 min while P. niruri and V. album reduced the glucose level to 16.87 and 17.33%, respectively. In alloxan diabetic rats, the extracts caused a significant (P < 0.05) non-dose-related reduction in blood glucose with 52.31 (O. basilicum), 44.29 (P. niruri) and 16.71% (V. album) maximum reduction at 6 h. Key words: Alloxan, diabetes mellitus, Nigerian medicinal plants.

African biodiversity has been the source of several promising anticancer drugs. Discoveries through the United States National Cancer Institute (NCI) programme prior to 1986 have led to the development of analogues of the combretastatins, one of which has been granted orphan drug status for the treatment of anaplastic thyroid cancer, and several others which are in clinical trials. Conjugates of maytansanoid derivatives, DM1 and DM4, with various monoclonal antibodies targeting a variety of cancers are showing promise in clinical trials. One, T-DM1 or trastuzumab emtansine, has been approved by the US Food and Drug Administration for the treatment of patients with HER2-positive, late-stage (metastatic) breast cancer. Since 1987, the NCI, through contracts with Missouri Botanical Garden and Coral Reef Research Foundation, has undertaken plant and marine organism collections respectively in several African countries. Collections have been performed subject to the terms of the NCI Letter of Collection or Memorandum of Understanding, which ensure 'fair and equitable' collaboration and benefit sharing, and in most instances, agreements based on these documents were signed with the source country authorities or qualified organizations. Through the International Cooperative Biodiversity Group programme, the Fogarty International Center of the National Institutes of Health (NIH), together with other NIH Institutes and US government agencies, has coordinated programmes in several African countries aimed at drug discovery, biodiversity conservation, and host country capacity building, which follow the same principles as those practised by NCI. Aspects of these programmes focused on anticancer drug discovery and development are discussed.

As part of our ongoing anti-infective discovery program based on plants employed in African Traditional Medicine, bioactive plants extract were selected for preparative separations of their secondary metabolites using High-Speed Countercurrent Chromatography (HSCCC) [1]. These phytochemicals were separated by a type-J multilayer coil planet centrifuge including the Spiral Tube Support (STS) and a newly developed flat-twisted tubing [2]. This paper describes the fundamentals of CCC separations, various CCC methods, particularly pH-zone refining countercurrent chromatography (pH-zone-refining CCC), trends in CCC instrument development in Dr. Ito's Bioseparation Laboratory at NIH as well as successful preparative separation and purification of three endemic plants known in African ethnomedicine for their various therapeutic properties. A broad selection of applications of pH-zone-refining CCC involving a wide variety of compounds is described. Separation of alkaloids from Picralima nitida (Stapf) T. Durand & H. Durand seeds using a new flat-twisted tubing in the pH-zone-refining CCC mode yielded six major indole alkaloids including akuammine, akuammicine, alstonine, picraline, Melinonine A and akuammidine with purities ranging from 90% (Melinonine A) to 98% (akuammine). A leaf extract (10.0 g) from Larrea tridentata Coville yielded Anti-HIV lignans, NDGA (nordihydroguaiaretic acid, 1.9 g) and its monomethyl esters (3 – 0-methyl-NDGA and 4 – 0-methyl-NDGA 1.4 g). Likewise, pH-zone-refining CCC was applied to scale up the separation of five major biflavanones including 3”,4',4”',5,5”,7,7”-heptahydroxy-3,8”-biflavanone (GB1), GB-I-glucoside, GB-1a, GB-2 and kolaflavonone from the extracts of Garcinia kola Heckel seeds. In comparison to earlier CCC methods, the new STS system yielded very high partition efficiency with the best stationary phase retention in a shorter elution time. References: [1] Yang Y, Aisa HA, Ito Y (2009)J Chromatogr A, 1216(27): 5265 – 5271. [2] Ito Y, (1986) Crit Rev Anal Chem, 17(1): 65 – 143.

Managing schizophrenia has never been a trivial matter. Furthermore, while classical antipsychotics induce extrapyramidal side effects and hyperprolactinaemia, atypical antipsychotics lead to diabetes, hyperlipidaemia, and weight gain. Moreover, even with newer drugs, a sizable proportion of patients do not show significant improvement. Alstonine is an indole alkaloid identified as the major component of a plant-based remedy used in Nigeria to treat the mentally ill. Alstonine presents a clear antipsychotic profile in rodents, apparently with differential effects in distinct dopaminergic pathways. The aim of this study was to complement the antipsychotic profile of alstonine, verifying its effects on brain amines in mouse frontal cortex and striatum. Additionally, we examined if alstonine induces some hormonal and metabolic changes common to antipsychotics. HPLC data reveal that alstonine increases serotonergic transmission and increases intraneuronal dopamine catabolism. In relation to possible side effects, preliminary data suggest that alstonine does not affect prolactin levels, does not induce gains in body weight, but prevents the expected fasting-induced decrease in glucose levels. Overall, this study reinforces the proposal that alstonine is a potential innovative antipsychotic, and that a comprehensive understanding of its neurochemical basis may open new avenues to developing newer antipsychotic medications.

Extracts of named medicinal herbs (Garcinia kola, Zingiber oificinale, Aframonum melequeta and Ocimum viride) were formulated into an antitussive preparation to alleviate cough. Some physical properties of the cough syrup formulation evaluated were: specific gravity, pH, viscosity, content uniformity, and shelf life. The specific gravity and viscosity of the formulations were stable on storage, with glycerin-based formulations having higher values. The pH of the formulation varied from 4.2 to 5.3 and was also stable on storage. Glycerin-based formulations had lower pH values. The total flavonoids content of Streptol was calculated based on GB1 and found to be 46 mg. The estimated shelf life of the Streptol cough syrup was 4.5 years.

Negative symptoms of schizophrenia are particularly problematic due to their deleterious impact on a patient's social life. The indol alkaloid alstonine, the major component of traditional remedies used for treating mental illnesses in Nigeria, presents a clear antipsychotic-like profile in mice, as well as anxiolytic properties. Considering that social interaction is the core of negative symptoms, and that anxiolytic drugs can improve social interaction behavior, the aim of this study was to evaluate the effects of alstonine in the social interaction and MK801-induced social withdrawal models in mice. Sub-chronic (but not acute) treatment with alstonine 0.5 mg/kg (but not 1.0 mg/kg) significantly increased social interaction in mice. Moreover, MK801-induced social withdrawal was completely prevented by sulpiride (10 mg/kg) and alstonine 1.0 mg/kg, and partially prevented by alstonine 0.5 mg/kg. The study indicates that alstonine not only increases social interaction in normal mice, but also averts social deficits attributable to negative symptoms of schizophrenia. This study reinforces and complements the antipsychotic-like profile of alstonine, and emphasizes its potential as a drug useful for the management of negative symptoms in schizophrenia.

Background: Cystic fibrosis (CF) results from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a chloride channel localized at the plasma membrane of diverse epithelia. The most common mutation leading to CF, F508, occurs in the first nucleotide-binding domain (NBD1) of CFTR. The F508 mutation disrupts protein processing, leading to a decreased level of mutant channels at the plasma membrane and reduced transepithelial chloride permeability. Partial correction of the F508 molecular defect in vitro is achieved by incubation of cells with several classes of chemical chaperones, indicating that further investigation of novel small molecules is warranted as a means for producing new therapies for CF. Materials and Methods: The yeast two-hybrid assay was used to study the effect of CF-causing mutations on the ability of NBD1 to self-associate and form dimers. A yeast strain demonstrating defective growth as a result of impaired NBD1 dimerization due to F508 was used as a drug discovery bioassay for the identification of plant natural product compounds restoring mutant NBD1 interaction. Active compounds were purified and the chemical structures determined. The purified compounds were tested in epithelial cells expressing CFTR F508 Address correspondence and reprint requests to: John Teem, Department of Biological Science, Biounit-238, Florida State University, Tallahassee, Florida 32306, USA. Phone: (850) 644-5121; fax: (850) 644-0481; e-mail: teem@bio.fsu.edu and the resulting effect on transepithelial chloride permeability was assessed using short-circuit chloride current measurements. Results: Wild-type NBD1 of CFTR forms homodimers in a yeast two-hybrid assay. CF-causing mutations within NBD1 that result in defective processing of CFTR ( F508, I507, and S549R) disrupted NBD1 interaction in yeast. In contrast, a CF-causing mutation that does not impair CFTR processing (G551D) had no effect on NBD1 dimerization. Using the yeast-based assay, we identified a novel limonoid compound (TS3) that corrected the F508 NBD1 dimerization defect in yeast and also increased the chloride permeability of Fisher Rat Thyroid (FRT) cells stably expressing CFTR F508. Conclusion: The establishment of a phenotype for the F508 mutation in the yeast two-hybrid system yielded a simple assay for the identification of small molecules that interact with the mutant NBD1 and restore dimerization. The natural product compound identified using the system (TS3) was found to increase chloride conductance in epithelial cells to an extent comparable to genistein, a known CFTR activator. The yeast system will thus be useful for further identification of compounds with potential for CF drug therapy.

Antimicrobial activity-directed fractionation of the seeds of Aframomum longifolius (Zingiberaceae) afforded two new labdane-type diterpenoids, 15-hydroxy-15-methoxylabda-8(17), 12( E)-dien-16-al (aframolin A) ( 1) and 8beta(17)-epoxy-15,15-dimethoxylabd-12( E)-en-16-al (aframolin B) ( 2), together with the known diterpenes labda-8(17),12( E)-diene-15,16-dial ( 3) and aframodial ( 4). Their structures were determined by spectroscopic methods. Compound 4 showed significant antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus (MRS) while 1, 2 and 3 were found to be inactive.

From an extract of the stem bark of Xymalos monospora, a bis-benzylisoquinoline alkaloid (1), three benzylisoquinoline alkaloids (mollinedine, 1-(p-methoxybenzyl)-6,7-methylenedioxyisoquino-line, doryafranine), and an aporphine alkaloid (N-methyllaurotetanine) were isolated. These compounds were tested for growth inhibitory activity against bloodstream forms of three strains of African trypanosomes. In vitro IC 50 values starting from 1.8 μg /mL were obtained.

7,8-dimethoxy-N-methylflindersine and 7,8-dimethoxy-3-(3-methylbut-2-enyl)-2-quinoline were isolated from the stem bark of Araliopsis tabouensis and their structures were assigned base on their 1H and 13C-NMR, DEPT 135, Gradient HMBC, G-HMQC and G-DQF-Cosy characteristics. The IC50 value in antimalarial bioassays vary from 1.8 to 4.7 μg/ml. Key words: Araliopsis tabouensis, structural determination, antimalarial properties. Journal of Pharmaceutical and Allied Sciences Vol.2(2) 2005: 214-218

Psychiatry co-morbidity with epilepsy is common and often requires the combined use of psychotropic and antiepileptic drugs (AEDs). For schizophrenic patients, the occurrence of seizures with atypical agents is highest among antipsychotics, although these agents are more effective in alleviating symptoms (including negative symptoms) and are associated with fewer extrapiramidal effects. The indol alkaloid alstonine is the major component of plants used by traditional Nigerian psychiatrists as anti-dementia drugs. The alkaloid presents an experimental profile very similar to the atypical antipsychotic clozapine. This study aimed to compare the pro-convulsant activity of these two antipsychotic compounds. Through repetitive administration over a 30-day period in a kindling paradigm, it is shown that, unlike clozapine, alstonine does not possess pro-convulsant activity. The data adds to previous suggestions that alstonine deserves to be scrutinized as a model for the development of newer antipsychotics.

A novel pyranoquinoline alkaloid 3,4-dihydro-3-hydroxy-5-methoxy-2,2,10-trimethylpyrano [2,3-b] quinoline named tabouensinium chloride ( 1), was isolated from the stem bark of Araliopsis tabouensis along with twelve known quinoline alkaloids. In addition, the known flindisol, lupeol and beta-sitosterol glucoside were also identified. Their structures were deduced from spectral data.

Picralima nitida alkaloids have been shown to possess in vitro antimalarial activity comparable to the clinical antimalarial chloroquine and quinine. The in vitro IC50 values for these alkaloids ranged from 0.01 to 0.9 mug/mL against chloroquine-sensitive (136) and chloroquine-resistant (W2) strains of Plasmodium falciparum. As part of our continuing research aimed at identifying new antimalarial leads from African rain forest plants, we have been highly successful in employing pH-zone-refining counter-current chromatography (CCC) to separate and isolate the Picralima alkaloids. The separation was performed in two steps with a two-phase solvent system composed of tert-butyl methyl ether (MTBE)/acetonitrile/water (2: 2: 3, v/v), in which the lower phase was used as the mobile phase at a flow-rate of 2.0 mL min(-1) in the head-to-tail elution mode pH-zone-refining counter-current chromatography. The resulting fractions contained the alkaloids alstonine, akuammigine, akuammine, picraline, akuammine, akuammicine, picratidine were identified using thermospray liquid chromatography-mass spectrometry (LC-MS) and by TLC co-elution experiments with authentic samples. The application of pH-zone-refining CCC to perform successful separations at the multigram level will be discussed. The Picralima alkaloids may represent an entirely new antimalarial chemotype with possible pharmacokinetics advantages over the existing drugs.

No Abstract. Journal of the Cameroon Academy of Sciences Vol. 5 (Supplement) 2005: pp. 65-76

The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10). Compound 10 was obtained as its acetoxy derivative ( 10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.

A phytochemical study of the methylene chloride/methanol (1/1) extract of the leaves of Glossocalyx brevipes Benth. (Monimiaceae) afforded three new derivatives of homogentisic acid, methyl 2-(1'beta-geranyl-5'beta-hydroxy-2'-oxocyclohex-3'-enyl)acetate (1), 2-(1'beta-geranyl-5'beta-hydroxy-2'-oxocyclohex-3'-enyl)acetic acid (2), methyl 2-(1'beta-geranyl-5'beta-hydroxy-4'beta-methoxy-2'-oxocyclohexyl)acetate (3), and two known alkaloids, aristololactam BII and liriodenine. Compounds 1 and 2 and liriodenine showed modest in vitro activity against Plasmodium falciparum.