Investigation of dengue-malaria coinfection among febrile patients consulting at Ngaoundere Regional Hospital, Cameroon.

This study aimed at evaluating the seroprevalence of dengue among malarious patients consulting at the Ngaoundere Regional Hospital. During 2 months and a half, 174 participants were recruited and their blood samples were screened for Plasmodium spp and then for Dengue virus (DENV) infection using rapid diagnostic tests. Also, hematological asparameters were measured using a hematology autoanalyzer. Among patients tested, 134 (77.01%) were malaria-positive, and 12/134 (8.95%) were coinfected. In this population, 8/12 (66.67%) were only anti-DENV IgM-positive, 3/12 (25%) were both NS1 and anti-DENV IgM positive, and 1/12 (8.33%) were anti-DENV IgG-positive. Furthermore, women were more affected (58.3%) than men (41.7%). The most affected age groups were young people aged less than or equal to 15 years (33.3%) and adults aged between 30 and 45 years (33.3%). A significant association (p < .05; odds ratio [OR] = 5.16) was found between the age range (30-45) and dengue-malaria coinfection. Similarly, we noted a significant association between the coinfection, and joint pain (p < .05; OR = 6.15), fatigue (p < .01; OR = 5.74), and chills (p < .05; OR = 0). Analysis of hematologic parameters showed a significant decrease (p < .001) in platelets in coinfected patients compared with monoinfected patients. In conclusion, dengue-malaria coinfection is a reality in Ngaoundere city and associated with the appearance of clinical features which predict the disease severity.

Biflavonoid Methylchamaejasmin and Khaya grandifoliola Extract Inhibit NLRP3 Inflammasome in THP-1 Cell Model of Neuroinflammation.

Neuroinflammation is a common hallmark of Alzheimer's disease (AD), with NLRP3 inflammasome proven to be activated in microglia of AD patients' brains. In this study, a newly isolated biflavonoid (7,7'-di-O-methylchamaejasmin/M8) and a crude extract of the plant Khaya grandifoliola (KG) were investigated for their inhibitory effect on inflammasome activation. In preliminary experiments, M8 and KG showed no cytotoxicity on human macrophage-like differentiated THP-1 cells and exhibited anti-inflammatory inhibition of nitric oxide produced following lipopolysaccharide stimulation. Furthermore, M8 and KG blocked IL-1ß and IL-18 production by reducing NLRP3 inflammasome components including NFκB, NLRP3, Caspase-1, pro-IL-1ß, and pro-IL-18 at the mRNA and protein levels. Regarding the formation of ASC (apoptosis-associated speck-like protein containing a CARD) specks during inflammasome activation, the size and fluorescent intensity of the existing specks were unchanged across all treatment conditions. However, M8 and KG treatments were shown to prevent further speck formation. In addition, experiments on amyloid ß phagocytosis showed that M8 and KG pretreatments can restore the phagocytic activity of THP-1 cells, which was impaired following inflammasome activation. Altogether, our findings describe for the first time a promising role of biflavonoids and KG extract in preventing inflammasome activation and protecting against neuroinflammation, a key factor in AD development.

Bioactive Fractions Isolated from Harungana madagascariensis Lam. and Psorospermum aurantiacum Engl. Regulate Collagen and Melanin Biosynthesis Gene Expression in UVB-Irradiated Cells with Additional Anti-Inflammatory Potential.

BACKGROUND: Harungana madagascariensis (HM) and Psorospermum aurantiacum (PA), used traditionally for skin care, have been reported to upregulate the expression of intracellular antioxidant genes, thereby preventing melanoma and protecting fibroblast cell lines from Ultraviolet B (UVB)-induced intracellular oxidative stress. AIMS: This investigation aimed to identify major compounds in bioactive fractions using bioassay- guided fractionation. METHODS: The anti-inflammatory effect of fractions was determined by measuring their inhibitory activity on 15-lipoxygenase and nitric oxide (NO) in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Additionally, the anti-aging efficacy of the fractions was determined by assessing the expression of markers for the aging process, i.e., expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), procollagen type-1 (COL1A1), and matrix metalloproteinase- 1 (MMP-1) in UVB-induced photoaging in skin cell-lines. Furthermore, UHPLCMS- based identification of the bioactive compounds from the most prominent fraction was also carried out. RESULTS: Hexane fraction of HM significantly inhibited (p <0.05) the 15-lipoxygenase (IC50 = 46.80 µg/mL) and NO production (IC50 = 66.55 µg/mL), whereas hexane fraction of PA was effective (p <0.05) in inhibiting 15-lipoxygenase activity (IC50 = 27.55 µg/mL). Furthermore, the hexane fraction of HM and methanol fraction of PA were significantly effective (p <0.05) in reverting the UVB-mediated altered expressions of MMP-1, TYR, TRP-1, and COL1A1. Furthermore, hexane fraction of HM revealed the presence of harunganin and betulinic acid, whereas vismion D, vismin, kenganthranol B, and bianthrone 1a were identified from the methanol fraction of PA. CONCLUSION: Overall, the hexane fraction of HM and methanol fraction of PA displayed effective anti-aging activities, with additional anti-inflammatory effects.

Effect of the aqueous extract of Senecio biafrae (Oliv. & Hiern) J. Moore on sexual maturation of immature female rat.

BACKGROUND: Senecio biafrae (Asteraceae) is a medicinal plant widely used by traditional healers in the western region of Cameroon for the treatment of female infertility. This experiment was designed to evaluate the effect of the aqueous extract from leaves and stems of S. biafrae (AESb) on the onset of puberty and some biochemical and physiological parameters of reproduction in immature Wistar female rats. METHODS: Different doses of AESb were daily and orally administered to immature female rats (13 animals/group) for 30 days. At the end of the treatment period, six animal of each experimental group were sacrificed and their body, ovarian, uterus weight; uterine, ovarian protein or cholesterol level as well as data on puberty onset recorded. The remaining animals of each group were used for the fertility test and some gestational parameters recorded. RESULTS: A linear increase in the growth rate of all animals was observed. The body weight gain in animals treated at the dose of 8 mg/kg of AESb significantly increased (p < 0.05) after 25 days of treatment while those receiving the doses of 32 and 64 mg/kg presented a significantly low body weight gain starting from the 19th day till the end of the treatment period. The ages (days) of animals at vaginal opening (VO) was significantly reduced (p < 0.05) in those treated with the doses of 32 (41.25 ± 0.51) and 64 mg/kg (41.42 ± 0.54) as compared to control animals (43.33 ± 0.73). AESb significantly increased (p < 0.05) the ovarian weight and the number of corpora lutea in animals treated with 8 mg/kg as well as the uterine weight and protein levels irrespective of the dose. No significant effect of the extract on various fertility and gestational parameters was registered. CONCLUSION: The overall results of the present study provide evidence on the puberty onset induction and ovarian folliculogenesis effect of AESb in immature female rat.

Khaya grandifoliola active fraction as a source of therapeutic compounds for Alzheimer's disease treatment: In silico validation of identified compounds.

Overproduction of Nitric oxide (NO) and many other pro-inflammatory mediators are responsible for many pathological disorders in humans, including Alzheimer's disease (AD). In this study, active fractions isolated from Khaya grandifoliola (Kg) were screened for their inhibitory activities against NO production in lipopolysaccharide (LPS)-activated microglia. Among the 5 fractions tested, Kg25 was the most active and showed potent inhibitory activity towards NO production. The fraction further showed inhibitory effect on iNOS's mRNA expression and other major pro-inflammatory cytokines including TNFα and IL1-ß. Study of the effect of Kg25 on p38MAPKinase and JNK3 showed that the fraction inhibits these signaling pathways known to be involved in cell inflammatory pathways. These observations were confirmed at the protein level with Kg25 inhibiting iNOS and p38MAPK protein expressions in N9 cells. Analysis of Kg25 composition by HPLC identified 3 main compounds, namely: 6 phenyl, 4-(1`oxyehylphenyl) hexane, Carbamic acid, (4-methly-1-phenyl)-1, phenyl, and Benzene, 1 1`-(oxydiethylidene) bis. The above mentionned compounds were further analyzed for their bioactivity against the p38MAPKinase and iNOS receptors using molecular docking. MolDock results showed that 1-phenylethyl N-(4-methylphenyl)carbamate (compound 2) possesses the highest binding affinity (for iNOS); and 1-(1-phenylethoxy)ethylbenzene (compound 3) (for pMAPK) respectively and both compounds interact well with the active site residues. Hence, these compounds could be considered as scaffolds for further development of lead- drugs targeting neuroinflammation in AD.

Hepatoprotective and antioxidant arylbenzofurans and flavonoids from the twigs of Morus mesozygia.

The chemical investigation of the twigs of Morus mesozygia resulted in the isolation of three new prenylated 2-arylbenzofurans, named moracin KM, LM, and SC (1-3), nine known 2-arylbenzofurans (4-12), and two known flavonoids (13-14). The structures of the new compounds were established as [2'',3'':6,7]-(6-(S)-hydroxymethyl-6-methylpyrano)-2-(3,5-dihydroxyphenyl)benzofuran-5-ol (1), [2'',3'':6,7]-(4,7-dihydro-6-methyloxepine)-2-(3-hydroxy-5-methoxyphenyl)benzofuran-5-ol (2), and [2'',3'':6,7]-(6,6-dimethylpyrano)-2-(3,5-dihydroxyphenyl)benzofuran (3). One of the new compounds, moracin LM (2), displayed modest antioxidant activity, whereas known compounds 4, 13, and 14 showed significant hepatoprotective and antioxidant activities.

Effects of maneb on testosterone release in male rats.

Maneb (Manganese ethylene-bis-dithiocarbamate) is a widely used fungicide in agriculture. In order to investigate its effect on male reproductive function, rats were intraperitonealy injected with maneb (1 and 4 mg/kg) for 9 or 18 days. After 6 and 14 days of treatment, the animals received human chorionic gonadotropin (hCG) via a jugular catheter and blood samples were collected at several intervals subsequent to the challenge. They were thereafter decapitated after 9 or 18 days, and organs (i.e., liver, seminal vesicles, and kidneys) were weighed. Leydig cells prepared from rats after 18 days of treatment were incubated with or without different stimulators or precursors [hCG, A23187, 25-OH-cholesterol (25-OH-C), or androstenedione] for 1 hour, and the media were analyzed for testosterone or pregnenolone. Liver glutathione and thiobarbituric acid reactive substances (TBARS) as well as serum alanine aminotransferase (ALT) activity were also measured. Further, Leydig cells and testicular interstitial cells (TICs) prepared from normal rats were incubated with maneb (3-100 µM) for 1 or 2 hours, and testosterone release was assessed. The results showed that administration of maneb (4 mg/kg) for 9 and 18 days did not alter liver function, but resulted in a decrease of basal level of plasma testosterone (P < 0.01). In addition, basal testosterone and pregnenolone release by Leydig cells prepared from maneb 18-day treated animals were significantly reduced (P < 0.05). However, acute in vitro exposure of TIC or Leydig cells to maneb did not alter their testosterone release. These results suggested that maneb alters testosterone production, at least in part, through inhibition of CYP11A1 activitiy.

Hepatoprotective Activity of Leptadenia hastata (Asclepiadaceae) on Acetaminophen-Induced Toxicity in Mice: In Vivo Study and Characterization of Bioactive Compounds through Molecular Docking Approaches.

MATERIALS AND METHODS: Various aqueous extracts were prepared from this plant and preadministered per os to albino mice 3 h before APAP administration, once daily for one week. Animals from the normal group were given only distilled water while those from negative control received only APAP 250 mg/kg. After treatment, mice were sacrificed, the liver was collected for histopathology analysis, and different biochemical markers (alanine aminotransferase (ALT), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), malondialdehyde (MDA), and tumor necrosis factor-alpha (TNFα)) were measured. The content of the active extract was analyzed by HPLC/UV. Molecular docking was conducted using iGEMDOCK software, and the drug-likeness and pharmacokinetic profiles were evaluated using Swiss ADME. RESULTS: APAP administration significantly increased (p < 0.001) ALT in liver homogenates when compared to normal controls whereas the stem decoction at 250 mg/kg significantly (p < 0.001) reduced this activity to a normal value comparable to silymarin 50 mg/kg which is better than leaf and root extracts. Moreover, the stem decoction also significantly reduced the MDA levels (p < 0.05) and increased those of GSH, SOD, and CAT (p < 0.001) at doses of 250 and 500 mg/kg compared to the negative control. A significant (p < 0.001) decrease of TNFα levels and leukocyte infiltration was observed following treatment with this extract. The HPLC/UV analysis of the decoction revealed the presence of dihydroxycoumarin, quinine, and scopoletin with the following retention times: 2.6, 5.1, and 7.01 min, respectively. In silico studies showed that quinine and dihydroxycoumarin had great potentials to be orally administered drugs and possessed strong binding affinities with TNFα, TNF receptor, cyclooxygenase-2, iNOS, cytochrome P450 2E1, and GSH reductase. CONCLUSION: Based on these results, L. hastata could be considered a source of promising hepatoprotective compounds with antioxidant and anti-inflammatory properties.

New Insights into Bioactive Compounds from the Medicinal Plant Spathodea campanulata P. Beauv. and Their Activity against Helicobacter pylori.

The medicinal plant Spathodea campanulata P. Beauv. (Bignoniaceae) has been traditionally applied for the prevention and treatment of diseases of the kidney and urinary system, the skin, the gastrointestinal tract, and inflammation in general. The present work shows for the first time how chemical components from this plant inhibit Helicobacter pylori growth by urease inhibition and modulation of virulence factors. The crude extract and the main fractions of S. campanulata bark were tested on H. pylori isolated strains and the active ones were further fractionated. Fractions and sub-fractions of the plant crude extract were characterized by ultra-high-performance liquid chromatographic tandem high resolution-mass spectrometry detection (UHPLC-HRMS). Several phenolics and triterpenoids were identified. Among the sub-fractions obtained, SB2 showed the capacity to inhibit H. pylori urease in a heterologous bacterial model. One additional sub-fraction (SE3) was able to simultaneously modulate the expression of two adhesins (HopZ and BabA) and one cytotoxin (CagA). The flavonol kaempferol was identified as the most interesting compound that deserves further investigation as a new hit for its capacity to modulate H. pylori virulence factors.

Prenylated arylbenzofuran derivatives from Morus mesozygia with antioxidant activity.

Five prenylated arylbenzofurans, moracins Q-U, were isolated from Morus mesozygia (Moraceae). Their structures were elucidated on the basis of spectroscopic evidence. Along with these compounds, 3beta-acetoxyurs-12-en-11-one, marsformoxide, moracin C, moracin M, moracin K, artocarpesin, cycloartocarpesin, morachalcone A were also isolated. Four of the five compounds, (moracins R-U) displayed potent antioxidant activity.

Dengue virus infection in people residing in Africa: a systematic review and meta-analysis of prevalence studies.

Better knowledge of the face of the current dengue virus (DENV) epidemiology in Africa can help to implement efficient strategies to curb the burden of dengue fever. We conducted this systematic review and meta-analysis to determine the prevalence of DENV infection in Africa. We searched PubMed, EMBASE, African Journals Online, and Africa Index Medicus from January 1st, 2000 to June 10th, 2019 without any language restriction. We used a random-effects model to pool studies. A total of 76 studies (80,977 participants; 24 countries) were included. No study had high risk of bias. Twenty-two (29%) had moderate and 54 (71%) had low risk of bias. In apparently healthy individuals, the pooled prevalence of DENV was 15.6% (95% confidence interval 9.9-22.2), 3.5% (0.8-7.8), and 0.0% (0.0-0.5) respectively for immunoglobulins (Ig) G, IgM, and for ribonucleic acid (RNA) in apparently healthy populations. In populations presenting with fever, the prevalence was 24.8% (13.8-37.8), 10.8% (3.8-20.6k) and 8.4% (3.7-14.4) for IgG, IgM, and for RNA respectively. There was heterogeneity in the distribution between different regions of Africa. The prevalence of DENV infection is high in the African continent. Dengue fever therefore deserves more attention from healthcare workers, researchers, and health policy makers.

Induction of Mkp-1 and Nuclear Translocation of Nrf2 by Limonoids from Khaya grandifoliola C.DC Protect L-02 Hepatocytes against Acetaminophen-Induced Hepatotoxicity.

Drug-induced liver injury (DILI) is a major clinical problem where natural compounds hold promise for its abrogation. Khaya grandifoliola (Meliaceae) is used in Cameroonian traditional medicine for the treatment of liver related diseases and has been studied for its hepatoprotective properties. Till date, reports showing the hepatoprotective molecular mechanism of the plant are lacking. The aim of this study was therefore to identify compounds from the plant bearing hepatoprotective activity and the related molecular mechanism by assessing their effects against acetaminophen (APAP)-induced hepatotoxicity in normal human liver L-02 cells line. The cells were exposed to APAP (10 mM) or co-treated with phytochemical compounds (40 µM) over a period of 36 h and, biochemical and molecular parameters assessed. Three known limonoids namely 17-epi-methyl-6-hydroxylangolensate, 7-deacetoxy-7-oxogedunin and deacetoxy-7R-hydroxygedunin were identified. The results of cells viability and membrane integrity, reactive oxygen species generation and lipid membrane peroxidation assays, cellular glutathione content determination as well as expression of cytochrome P450 2E1 demonstrated the protective action of the limonoids. Immunoblotting analysis revealed that limonoids inhibited APAP-induced c-Jun N-terminal Kinase phosphorylation (p-JNK), mitochondrial translocation of p-JNK and Bcl2-associated X Protein, and the release of Apoptosis-inducing Factor into the cytosol. Interestingly, limonoids increased the expression of Mitogen-activated Protein Kinase Phosphatase (Mkp)-1, an endogenous inhibitor of JNK phosphorylation and, induced the nuclear translocation of Nuclear Factor Erythroid 2-related Factor-2 (Nrf2) and decreased the expression of Kelch-like ECH-associated Protein-1. The limonoids also reversed the APAP-induced decreased mRNA levels of Catalase, Superoxide Dismutase-1, Glutathione-S-Transferase and Methionine Adenosyltransferase-1A. The obtained results suggest that the isolated limonoids protect L-02 hepatocytes against APAP-induced hepatotoxicity mainly through increase expression of Mkp-1 and nuclear translocation of Nrf2. Thus, these compounds are in part responsible of the hepatoprotective activity of K. grandifoliola and further analysis including in vivo and toxicological studies are needed to select the most potent compound that may be useful as therapeutic agents against DILI.

Effects of extracts from Hibiscus macranthus and Basella alba mixture on testosterone production in vitro in adult rat testes slices.

AIM: To find an in vitro system for the measurement of the androgenic effects of different extracts of Hibiscus macranthus (Malvaceae) and Basella alba (Basellaceae). METHODS: The production of testosterone from testes slices incubated in two media, either Krebs-Henseleit buffer containing 0.5% Bovine serum albumin (BSA) or Dubecco's Modified Eagle's medium-F12 Ham nutrient mixture (DME/Ham F12), under a mixture of 5% CO2 in 95% air was determined either in the presence or absence of cofactors and Hibiscus macranthus plus Basella alba (HMBA) extracts. RESULTS: The testosterone production was increased in testes slices incubated in DME/Ham F12 medium in response to the cofactors (49%) and aqueous extracts (34%-60% according to dilutions). Under the same atmospheric conditions, there was no positive response of the testes slices to either cofactor or HMBA extract stimulation in Krebs-Henseleit buffer containing 0.5% BSA. In further investigations related to the effect of HMBA, the DME/Ham F12 medium was used. The results obtained from the in vitro test showed that the activity was present mainly in methylene chloride and methanol, since these extracts induced an increase in testosterone production by testes slices. CONCLUSION: The testes slice system is suitable to be used for further in vitro investigations of the isolation of androgenic bioactive components of plants.

Effects of Basella alba and Hibiscus macranthus extracts on testosterone production of adult rat and bull Leydig cells.

AIM: To determine the androgenic effects of Basella alba and Hibiscus macranthus extracts in the rat and the bull, and to develop a novel in vitro test system using Leydig cells from bull testes. METHODS: The effect of methanol extracts from both plants on testosterone production in isolated Leydig cells from the rat and the bull was analyzed using 125I-radioimmunoassay (125I-RIA). Rat Leydig cells were obtained by common methods, whereas a novel technique was used to purify Leydig cells from bull testes. RESULTS: Bull testes from the slaughter house were a cheap source of pure Leydig cells. In culture, these cells produced testosterone for 5-6 days, which can be stimulated by human chorionic gonadotrophin (hCG). Basella alba extracts significantly enhanced testosterone production in bull and rat Leydig cells in a concentration-dependent manner. Hibiscus macranthus showed no androgenic effect but was shown to inhibit testosterone production at higher concentrations. CONCLUSION: Leydig cells purified from bull testes can be used as an alternative tool in experimental animal research. Certain fractions of Basella alba extract demonstrated androgenic potential whereas Hibiscus macranthus extracts did not.

Natural polyphenols binding to amyloid: a broad class of compounds to treat different human amyloid diseases.

Polyphenols are a large group of phytonutrients found in herbal beverages and foods. They have manifold biological activities, including antioxidative, antimicrobial, and anti-inflammatory properties. Interestingly, some polyphenols bind to amyloid and substantially ameliorate amyloid diseases. Misfolding, aggregation, and accumulation of amyloid fibrils in tissues or organs leads to a group of disorders, called amyloidoses. Prominent diseases are Alzheimer's, Parkinson's, and Huntington's disease, but there are other, less well-known diseases wherein accumulation of misfolded protein is a prominent feature. Amyloidoses are a major burden to public health. In particular, Alzheimer's disease shows a strong increase in patient numbers. Accelerated development of effective therapies for amyloidoses is a necessity. A viable strategy can be the prevention or reduction of protein misfolding, thus reducing amyloid build-up by restoring the cellular aggretome. Amyloid-binding polyphenols affect amyloid formation on various levels, e.g. by inhibiting fibril formation or steering oligomer formation into unstructured, nontoxic pathways. Consequently, preclinical studies demonstrate reduction of amyloid-formation by polyphenols. Amyloid-binding polyphenols might be suitable lead structures for development of imaging agents for early detection of disease and monitoring amyloid deposition. Intake of dietary polyphenols might be relevant to the prevention of amyloidoses. Nutraceutical strategies might be a way to reduce amyloid diseases.

Androgenic effect of Mondia whitei roots in male rats.

AIM: To determine the effect of the aqueous extract of Mondia whitei (Periplocaceae) roots on testosterone production and fertility of male rats. METHODS: Adult male Wistar rats were used. In the acute study, 20 rats were randomly divided into 5 groups of 4 animals each. Four treated groups were administered orally a single dose of Mondia whitei (400 mg/kg) and the controls received a similar amount of distilled water. One group of animals were sacrificed by cervical dislocation 1, 2, 4 and 6 h after treatment, respectively. The controls were sacrificed at 6 h. Testicular testosterone was determined by radioimmunoassay. In the chronic study, 28 rats were divided at random into 4 groups of 7 animals each: Groups 1, 2 and 3 were given orally the plant extract (400 mg.kg(-1).day(-1)) for 2, 4 and 8 days, respectively. The animals of Groups 1 and 2 were sacrificed 24 hours after the last dosing. The controls (Group 4) received the same amount of distilled water for 8 days. The fertility was assessed only in Groups 3 and 4 and after that, the animals were sacrificed and the epididymal sperm density, the serum testosterone and the testicular testosterone and 17 beta-estradiol were assayed. The serum, testicular and epidydimal protein contents were also determined. RESULTS: In the acute treatment groups, the serum and testicular concentrations of testosterone remained unchanged at all the time points. Chronic treatment for 8 days induced a significant increase in the testicular weight, the serum and testicular testosterone, the testicular protein content and the sperm density (P < 0.05-0.01), but did not affect the accessory gland weights, the serum protein contents, the testicular concentration of 17beta -estradiol and the fertility compared to the controls. CONCLUSION: Mondia whitei root extract possesses an androgenic property.

In vitro genotoxic and mutagenic evaluation of the aqueous extract of Codiaeum variegatum and its amoebicidal sub-fraction.

ETHNOPHARMACOLOGICAL RELEVANCE: Codiaeum variegatum, grown in many varieties, has been widely used as a houseplant based on its brightly decorative foliage. In addition, a variety of this plant has been used for a long time against bloody diarrhea by the local population in Cameroon. AIM OF THE STUDY: In our previous study, the aqueous extract of this plant and an isolated sub-fraction exhibited significant anti-amoebic activity on axenic culture of Entamoeba histolytica. Due to the medicinal value of these extracts, we promptly initiated to investigate their genotoxic and mutagenic potential in order to assure their safe and rationale usage in traditional healthcare system. MATERIAL AND METHODS: Both extracts were incubated with L5178Y mouse lymphoma cells, primary hepatic cells and HepG2 human hepatocellular carcinoma cells and their genotoxicity and mutagenicity were evaluated by quantifying DNA damage and chromosomal aberrations through comet assay, micronucleus assay and mouse lymphoma mutation assay. RESULTS: The aqueous extract of Codiaeum variegatum is not cytotoxic up to 2000 µg/mL while the amoebicidal fraction is significantly cytotoxic (≤40-55%) on L5178Y mouse lymphoma and HepG2 cells at concentrations higher than 500 µg/mL. Besides, no significant DNA damage and induction of micronucleus formation were identified at concentrations up to 2000 µg/mL. Moreover, the mutagenic potential of these extracts after short (4 h) and long term (24 h) treatment, revealed no significant gene mutation induction. CONCLUSION: The aqueous extract of Codiaeum variegatum and the amoebicidal fraction SF9B are neither genotoxic on non-competent or metabolic competent cell lines, nor mutagenic in mouse lymphoma mutation assay and therefore they could be safely used at lower doses for medicinal purpose.

Bioassay-guided fractionation of extracts from Codiaeum variegatum against Entamoeba histolytica discovers compounds that modify expression of ceramide biosynthesis related genes.

Leaves of Codiaeum variegatum ("garden croton") are used against bloody diarrhoea by local populations in Cameroon. This study aims to search for the active components from C. variegatum against Entamoeba histolytica, and thereby initiate the study of their mechanism of action. A bioassay-guided screening of the aqueous extracts from C. variegatum leaves and various fractions was carried out against trophozoites of E. histolytica axenic culture. We found that the anti-amoebic activity of extracts changed with respect to the collection criteria of leaves. Thereby, optimal conditions were defined for leaves' collection to maximise the anti-amoebic activity of the extracts. A fractionation process was performed, and we identified several sub-fractions (or isolated compounds) with significantly higher anti-amoebic activity compared to the unfractionated aqueous extract. Anti-amoebic activity of the most potent fraction was confirmed with the morphological characteristics of induced death in trophozoites, including cell rounding and lysis. Differential gene expression analysis using high-throughput RNA sequencing implies the potential mechanism of its anti-amoebic activity by targeting ceramide, a bioactive lipid involved in disturbance of biochemical processes within the cell membrane including differentiation, proliferation, cell growth arrest and apoptosis. Regulation of ceramide biosynthesis pathway as a target for anti-amoebic compounds is a novel finding which could be an alternative for drug development against E. histolytica.

Extensive phytochemical investigation of the polar constituents of Diospyros bipindensis Gürke traditionally used by Baka pygmies.

The water maceration and methanolic extract of the stem barks of Diospyros bipindensis, which is a medicinal plant used in Cameroon by Baka pygmies, revealed a complex high-performance liquid chromatography (HPLC) profile primarily composed of coumarin and naphthoquinone glycosides. The methanolic and apolar extracts also exhibited significant antifungal activity on a TLC bioautography assay against Candida albicans. HPLC-microfractionation in 96-well plates combined with bioautography enabled the rapid localization of the antifungal compound that was identified by HPLC-PDA and HPLC-MS analysis as plumbagin. These on-line structural information were also used to dereplicate four known compounds. The isolation of the polar constituents from the methanolic extract enabled the identification of eleven other compounds also present in the traditional preparation, nine of which are reported for the first time. The structures of those compounds were elucidated by UV, NMR and HR-MS analysis.