Evaluation of four Cameroonian medicinal plants for anticancer, antigonorrheal and antireverse transcriptase activities

Methanol extracts from the leaves, bark and roots of four Cameroonian medicinal plants, Bersama engleriana, Cupressus lusitanica, Vitellaria paradoxa and Guibourtia tessmannii were tested for their in vitro cytotoxicity, antigonorrheal and antireverse transcriptase activities. The XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt) assay, the dilution method and reverse transcriptase (RT) assay were used for the investigations. Preliminary phytochemical analysis of the extracts was also conducted using standard methods. Results showed that all extracts contained compounds belonging to the classes of phenols and terpenoids. They were also able to reduce in dose dependent manner, the proliferation of the cancer THP-1, DU145, HeLa, MCF-7, HepG2 and the normal Vero cells. IC50 values below 30 μg/ml were noted with extract from the three parts of B. engleriana on at least two of the five studied cancer cell lines, the lowest value of 5.9 μg/ml being obtained with sample from the bark. IC50 values below 30 μg/ml were also recorded with extracts from the leaves (on HeLa cells) and bark (on MCF-7) of G. tessmanii, and that from the bark of C. lusitanica on MCF-7. Extracts from B. engleriana and those from the bark of V. paradoxa gave the minimal inhibitory concentrations (MIC) values below 100 μg/ml on most of the 10 tested Nesseria gonorrhoeae strains. Extracts from B. engleriana also inhibited more than 80% the activity of the Human Immuno-deficiency Virus (HIV) enzyme. Finally, the results of the present study provide baseline information for the use of B. engleriana, C. lusitanica, G. tessmanii, V. paradoxa.http://www.elsevier.com/locate/etapnf201

Antibacterial constituents of three Cameroonian medicinal plants : Garcinia nobilis, Oricia suaveolens and Balsamocitrus camerunensis

BACKGROUND: Multidrug resistance is a worrying cause of treatment failure in bacterial infections. The search of bioactive constituents from medicinal plants against multidrug resistant (MDR) bacteria has significantly evolved in the two last decades. In the present study, twenty-two compounds (three terpenoids, eleven phenolics and eight alkaloids) isolated from three Cameroonian medicinal plants, namely Garcinia nobilis, Oricia suaveolens and Balsamocitrus camerunensis, as well as the crude extracts were tested for their antibacterial activities against Mycobacterium tuberculosis and Gram-negative bacteria amongst which were MDR active efflux pumps expressing phenotypes. METHODS: The microplate alamar blue assay (MABA) and the broth microdilution methods were used to determine the minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of the studied samples. RESULTS: The results of the MIC determinations indicate that, the best crude extract was that from G. nobilis (GNB), its inhibitory effects being noted against 12 of the 14 tested bacteria. The extract of GNB also exhibited better anti-tuberculosis (MIC of 128 μg/ml M. tuberculosis against ATCC 27294 strain) and antibacterial (MIC of 64 μg/ml against Escherichia coli ATCC10536) activities compared to the extracts of O. suaveolens and B. camerunensis. Interestingly, 4-prenyl-2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone (2), isolated from the most active extract GNB, also showed the best activity amongst compounds, inhibiting the growth of all the fourteen tested microorganisms. The lowest MIC value obtained with compound 2 was 8 μg/ml against M. tuberculosis ATCC 27294 and M. tuberculosis clinical MTCS2 strains. Other compounds showed selective activities with 11 of the 14 tested bacteria being sensitive to the xanthone, morusignin I (5) and the alkaloid, kokusaginine (13). CONCLUSIONS: The results of the present investigation provide evidence that the crude extract from G. nobilis, O. suaveolens and B. camerunensis as well as some of their compounds, and mostly compound 2 (isolated from G. nobilis,) could be considered as interesting natural antibacterial products.International Foundation for Science (IFS-Grant F/4579-2 to VK), TWAS for financial support for ICCBSTWAS fellowship at the H.E.J. Research Institute of Chemistry, International Center of Chemical Sciences, University of Karachi, Pakistan on year 2010 (HF).http://www.biomedcentral.com/bmccomplementalternmedam201

Synthesis and anticancer activity evaluation of some new 1,2,3,5-tetrazine derivatives attached to benzothiazole moiety

A series of novel tetrazine derivatives, containing benzothiazole framework, were prepared during the coupling reactions of some diazotized 2-aminobenzo[d]thiazole derivatives with p-acetaminophen. Their structures were elucidated based on NMR and MS spectrometry. The anticancer activity and the safety of the synthesized compounds along with the entire precursors were assessed against three human cancer cell lines and a normal cell line. All the synthesized compounds showed selective cytotoxic activity against the cancer cell lines used in comparison to the normal Vero cell line. Their IC50 values varied from 2.02 to 171.67 μM.The Cameroonian Ministry of Higher Education special research allocation, the German Academic Exchange Service (DAAD) and the University of Pretoria.https://www.arkat-usa.org/arkivoc-journalam2023Paraclinical Science

Prenylated isoflavanone from the roots of Erythrina sigmoidea

A novel prenylated isoflavanone, sigmoidin I, has been isolated from the roots of Erythrina sigmoidea, in addition to the known isoflavones, corylin and neobavaisoflavone and the known pterocarpan, phaseollidin. Its structure was established as 7,4'-dihydroxy-3'-methoxy-5'-(3-methylbut-2-enyl) isoflavanone by means of spectroscopic analyses and chemical transformations. Neobavaisoflavone displayed antifungal potency in vitro with minimum inhibitory concentrations against Aspergillus fumigatus and Cryptococcus neoformans, of 50 mg ml-1

Selective cytotoxic activity of isolated compounds from Globimetula dinklagei and Phragmanthera capitata (Loranthaceae)

This study aimed to evaluate the selective cytotoxicity of six natural compounds on four cancerous cells (MCF-7, HeLa, Caco-2 and A549) and two normal intestinal and lung cells (Hs1.Int and Wl-38) cells. We also attempted to analyze basically the structure–activity relationships and to understand the mechanism of action of active compounds using the Caspase-Glo® 3/7 kit. Globimetulin B (2) isolated from Globimetula dinklagei was significantly cytotoxic on cancerous cells with 50% inhibitory concentrations (IC50) ranging from 12.75 to 37.65 μM and the selectivity index (SI) values varying between 1.13 and 3.48 against both normal cells. The compound 3-O-β-d-glucopyranosyl-28-hydroxy-α-amyrin (5) isolated from Phragmanthera capitata exhibited the highest cytotoxic activity on HeLa cells with the IC50 of 6.88 μM and the SI of 5.20 and 8.71 against Hs1.Int and Wl-38 cells, respectively. A hydroxyl group at C-3 of compounds was suggested as playing an important role in the cytotoxic activity. The induction of caspase-3 and -7 activity represents some proof that apoptosis has occurred in treated cells. Globimetulin B (2) selectively killed cancer cells with less toxicity to non-cancerous cells as compared to conventional doxorubicin therapy.https://www.degruyter.com/view/j/znc2021-03-26hj2020Paraclinical Science

Antioxidant, antitumor and antimicrobial activities of the crude extract and compounds of the root bark of Allanblackia floribunda

CONTEXT: Allanblackia floribunda Oliver (Guttiferae) is an African medicinal plant used traditionally to treat a variety of ailments. OBJECTIVE: We investigated the antitumor, radical scavenging, antimycobacterial, antibacterial and antifungal activities of the root bark extract of A. floribunda and three isolated phenolics, namely 1,7-dihydroxyxanthone (1), morelloflavone (2) and 7′-O-glucoside of morelloflavone (3). MATERIALS AND METHODS: The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging assay was used for antioxidant tests, while crown gall tumor assay was used for assay of antitumor activity. The p-iodonitrotetrazolium chloride (INT) colorimetry and Microplate Alamar Blue Assay (MABA) were used for antimicrobial investigations. RESUSLTS: Moderate tumor reducing activity was observed with the extract, while better activities were recorded with compounds 2 and 3. The antimycobacterial and antitumor activities of the extract are being reported for the first time. The DPPH radical scavenging test showed that all the studied samples were able to scavenge more than 50% of the free radical, with compound 3 showing the best inhibitory activity (IC50 of 49.08 µg/mL). Compounds 1 to 3 prevented the growth of Mycobacterium smegmatis and both extract and compound 2 were active on M. tuberculosis. The lowest MIC value for the extract (9.76 μg/mL) was recorded against Enterobacter aerogenes while the corresponding value for the compounds (4.88 µg/mL) was obtained with compound 2 on Trichophyton rubrum. DISCUSSION AND CONCLUSION: The overall results of the present work provide baseline information for the potential use of the root bark extract of A. floribunda as an antimicrobial, antitumor and antioxidant phytomedicine.Authors acknowledge the financial support of the International Foundation for Science (IFS) (Grant no. F /4579-1 to VK) for the antimycobacterial assays and both IFS and the Organization for the Prohibition of Chemical Weapons, The Hague, Netherlands (OPCW),grant F/3969 to AAGB, and the technical support of Mr. P. Lunga of the University of Dschang

Cytotoxicity, nitric oxide and acetylcholinesterase inhibitory activity of three limonoids isolated from Trichilia welwitschii (Meliaceae)

BACKGROUND: Limonoids are highly oxygenated compounds with a prototypical structure. Their occurrence in the plant kingdom is mainly confined to plant families of Meliaceae and Rutaceae. Owing to their wide range of pharmacological and therapeutic properties, this study was aimed at investigating the potential nitric oxide (NO) and acetylcholinesterase (AChE) inhibitory activity and the cytotoxicity of three limonoids: trichilia lactone D5 (1), rohituka 3 (2) and dregeanin DM4 (3), isolated from Trichilia welwitschii C.DC RESULTS: Results indicated that the three limonoids had low cytotoxicity towards Vero cells with LC50 values ranging from 89.17 to 75.82 (μg/L. Compounds (2) and (3) had lower cytotoxicity compared to puromycin and doxorubicin used as reference cytotoxic compounds. Compound (1) (LC50 of 23.55 (μg/L) had good antiproliferative activity against RAW 264.7 cancer cells. At the lowest concentration tested (0.5 μg/mL), compound (2) and (3) released the lowest amount of nitric oxide (2.97 and 2.93 μM, respectively). The three limonoids had anti-AChE activity with IC50 values ranged of 19.13 (μg/L for (1), 34.15 (μg/L for (2) and 45.66 (μg/L for (3), compared to galantamine (IC50 of 8.22 ( g/mL) used as positive control CONCLUSION: The limonoid compounds studied in this work inhibited nitric oxide production in LPS-stimulated macrophages and had anti-AChE activity. Trichilia lactone D5 had potential antiproliferative activity against RAW 264.7 cancer cells. The limonoids had low cytotoxicity towards Vero cells lines. This study provided further examples of the importance of limonoids compounds as potential AChE inhibitors and anti-inflammatory agents targeting the inhibition of NO productio