Michel Tchimene - Academia.edu (original) (raw)

Papers by Michel Tchimene

Natural Product Communications, Dec 1, 2011

Phomosine K (1), a new phomosine derivative, has been isolated from Phomopsis sp., in addition to... more Phomosine K (1), a new phomosine derivative, has been isolated from Phomopsis sp., in addition to six known compounds: phomosine A (2), phenylalanine amide (3), 2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-en (4), (-)-phyllostine (5), (+)-epiepoxydon (6), and (+)-epoxydon monoacetate (7). Preliminary studies showed that compound 1 had strong antibacterial activity, while compounds 4-7 showed good antifungal, antibacterial, and algicidal properties, except compounds 4 and 6, which lacked antifungal activity.

Phytotherapy Research, 1996

Lychnophora salicifolia (Asteraceae), a native Brazilian medicinal plant used in folk medicine ag... more Lychnophora salicifolia (Asteraceae), a native Brazilian medicinal plant used in folk medicine against some diseases, revealed the presence of two known caryophyllene derivatives, in a satisfactory yield: lychnopholic acid 1 and acetyl lychnopholic acid 2. These compounds exhibited antifungal activity by the agar diffusion method, and antibacterial activity by the methods of diffusion and minimum inhibitory concentration (MIC). However, compound 2 was more potent than 1, suggesting that the acetyl group is responsible for antimicrobial activity.

Journal of the Cameroon …, 2007

Journal of Medicinal Plants Research, 2016

The antidiabetic properties of extracts of three Nigerian medicinal plants - Ocimum basilicum L. ... more 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. Ext...

Andrographolide (1) a bitter, diterpenes lactone is the most biologically active constituent from... more 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 exper...

Felix I Nwafor*, Michel K Tchimene, Peculiar F Onyekere, Nkechinyere O Nweze & Celestina I Orabue... more Felix I Nwafor*, Michel K Tchimene, Peculiar F Onyekere, Nkechinyere O Nweze & Celestina I Orabueze 1Department of Pharmacognosy and Environmental Medicines, University of Nigeria, Nsukka, 410 001, Enugu State, Nigeria; 2International Centre for Ethnomedicine and Drug Development (Inter CEDD), Nsukka, 410 002, Enugu State, Nigeria; Department of Plant Science and Biotechnology, University of Nigeria, Nsukka, 410 001, Enugu State, Nigeria; 4Departments of Pharmacognosy, University of Lagos, PMB 12003, Surulere, Lagos, Nigeria E-mails: felix.nwafor@unn.edu.ng, felixnucifera@gmail.com, mtchimene@yahoo.fr, peculiar.onyekere@unn.edu.ng, nkechinyere.nweze@unn.edu.ng, ifeoma_orabueze@yahoo.com

The need to find a broad-based nutritional and antimicrobial therapy gave impetus to this investi... more The need to find a broad-based nutritional and antimicrobial therapy gave impetus to this investigation. The crude extracts of Baphia nitida stem bark were used to check for antimicrobial effect on selected micro-organisms for possible nutritional and therapeutic application. The stem bark components were extracted with four solvent systems using maceration. A synthetic drug gentamycin - 80 mg/mL (2 mL) was dissolved in 20 mL of distilled water to obtained 8 mg/mL, was used as a control. The crude extract exhibited an antibacterial effect on gram-positive organisms (Staphylococcus aureus and Bacillus cereus), and gram-negative organism (Pseudomonas aeruginosa, and Escherichia coli) at 2 mg/mL. These showed competitiveness with the 8 mg/mL of the control drug. The normal hexane fraction had an effect on Staphylococcus aureus but showed no effect on other bacteria. Minimum inhibitory concentration (MIC) showed a dose-dependent decrease in the effect for the crude extract. Ethyl acetat...

The study was aimed at investigating the antioxidant properties of lupeol isolated from the metha... more The study was aimed at investigating the antioxidant properties of lupeol isolated from the methanol leaf extract of Crateva adansonii. In order to assess the antioxidant effect of lupeol in vitro (1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) spectrophotometric assay, Ferric reducing antioxidant power (FRAP) assay, Hydrogen peroxide scavenging assay, Hydroxyl radical scavenging assay, ABTS radical cation scavenging activity, Anti-lipid peroxidation assay, β -Carotene bleaching assay, Superoxide anion radical scavenging assay) and in vivo (Lipid peroxidation assay, Assay of catalase (CAT) activity, Assay of reduced glutathione (GSH) concentration) experimental models were used. The effect of DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging showed that lupeol had better percentage antioxidant activities at high concentrations when compared with ascorbic acid (88.40 % and 82.37 % at 800 μg/ml respectively). The FRAP (Ferric reducing antioxidant power) results were similar...

Journal of Pharmacognosy and Phytotherapy, 2018

The anti-inflammatory effect of the extract of Parinari kerstingii leaves was investigated using ... more The anti-inflammatory effect of the extract of Parinari kerstingii leaves was investigated using egg albumin-induced rat paw oedema, leukocyte mobilization, and acetic acid-induced vascular permeability assay methods. Heat and hypotonicity-induced heamolysis of human red blood cell membrane were also used to assess its membrane stabilizing effect and to determine its inhibitory property on phospholipase A 2 activity. Acute toxicity and phytochemical tests were also determined using standard methods. The methanol crude extract (MCE) of P. kerstingii reduced (p<0.05) the acetic acid-induced vascular permeability and increased agar-induced leukocyte mobilization in rats dose-dependently. Vascular permeability was inhibited by 24.85, 26.04 and 48.52% with 100, 200 and 400 mg/kg of the MCE, respectively. The total leukocyte count of the treated groups increased significantly (p<0.05) relative to the control group. The percentage membrane stability exhibited by the MCE was comparable with drug control, indomethacin. The MCE contains principles that protected the erythrocyte membranes effectively. More so, the extract inhibited (p<0.05) the activities of phospholipase A 2 and showed no significant difference in the phospholipase A 2 inhibitory effect as compared to the standard drug, prednisolone. The extract showed no toxicity at 5000 mg/kg. Phytochemical screenings revealed the presence of tannins, saponins, reducing sugars, phenols, soluble carbohydrates, alkaloids, terpenoids, steroids, hydrogen cyanide glycosides and flavonoids. This study indicated that the MCE of P. kerstingii leaf is relatively safe for consumption and has anti-inflammatory property. Also, it could prevent the haemolysis of human erythrocyte membrane.

Pharmacognosy Journal, 2015

Objective: The research was carried out to investigate the anti-inflammatory effect of ethanol ex... more Objective: The research was carried out to investigate the anti-inflammatory effect of ethanol extract, fraction (kolaviron) and compounds (garcinoic acid, GB1 and GB2) of Garcinia kola seeds. Materials and Method: To evaluate the acute anti-inflammatory effect of extract, fraction and compounds of G. kola carrageenan-induced edema model in wistar albino rats was used. Results: Kolaviron (50 mg/kg), garcinoic acid (50 mg/kg) and the crude extract (50 mg/kg) caused 100, 83 and 74% inhibition of carrageenan-induced paw edema respectively at 6 h post administration. Indomethacin (10 mg/ kg), the reference drug induced 100% inhibition of carrageenan-induced paw oedema. While GB1 (50 mg/kg) and GB2 (50 mg/kg) was prominent at 4, 5 and 6 h post administration. Conclusion: Results showed that the extract possessed anti-inflammatory activity, which have justified their use in Nigeria traditional medicine to treat inflammation.

Pharmacology & Pharmacy, 2015

European Journal of Medicinal Plants, 2015

Objective: The objective of the present study was designed to test the antioxidant activity and p... more Objective: The objective of the present study was designed to test the antioxidant activity and phytochemical property of the methanol/ methylene chloride (1:1) extract of Combretum obanense. Place and Duration of Study: The International Centre for Ethnomedicine and Drug Development (InterCEDD), 110 Aku Road Nsukka, Enugu State, Nigeria, between January 2014 and July 2014. Methodology: We had assessed methanol/methylene chloride (1:1) stem extract of C. obanense, for antioxidant potentials with the help of DPPH (1, 1-diphenyl-2-picryl hydrazyl) free radical scavenging, reducing power assay and phytochemical analysis.

Bulletin of the Chemical Society of Ethiopia, 2006

Monoterpenes belong to a large and diverse group of chemical compounds named terpenes. They repre... more Monoterpenes belong to a large and diverse group of chemical compounds named terpenes. They represent a group of naturally occurring organic compounds whose basic structure consists of two linked isoprene units, each of which is formed by a 5-carbon base. In this chapter, we provide the general biosynthetic pathways of monoterpenes; we report 35 new and 29 known monoterpenes isolated from African medicinal plants with their pharmacological activities.

Asian Pacific Journal of Tropical Medicine, 2014