Anti-inflammatory, Antinociceptive, and Toxicological Properties of Uvaria comperei Stem Crude Extract and Fractions.

The present study was carried out to investigate the anti-inflammatory activity of a methanolic extract and fractions of Uvaria comperei stems. The crude extract was obtained by maceration of the powder in methanol and fractions by vacuum chromatography from the methanolic extract. To study the anti-inflammatory activity in vitro, red blood cell lysis inhibition assay and albumin denaturation inhibition were performed, while in vivo measurements of carrageenan-induced paw oedema and formalin-induced pain in albino mice were performed. Acute toxicity and cytotoxicity studies of the fraction F2 were performed, as well as its HPLC, and some biochemical parameters were quantified. Uvaria comperei crude extract (UCCE) at 250 and 500 µg/mL completely inhibited albumin denaturation, while decreasing 75.5% of heat blood cell lysis at 500 µg/mL. The fractions 128-136 (F3), 10-11 (F1), and 56-62 (F2) at 500 µg/mL displayed a significant anti-inflammatory activity with percentages of inhibition of 60.5, 67.4, and 100%, respectively. Administration of fraction F2 (25, 50, and 100 mg/kg, p.o.) produced a dose-dependent inhibition of formalin-induced pain of 60.2% at 50 mg/kg in the neurogenic phase (p < 0.05) and 70.2% at 25 mg/kg in the inflammatory phase (p < 0.05). Similarly, the time-dependent increase in carrageenan-induced paw circumference induced by carrageenan was inhibited by pretreatment with F2: 50% of inhibition at 25 mg/kg after 30 min (p < 0.05) and 96.5% inhibition at 25 mg/kg after 6 h (p < 0.05). In this research, the fraction F2 presented its maximum analgesic property at 50 mg/kg, while it presented the highest anti-inflammatory property at 25 mg/kg. The oral lethal median dose (LD50) of F2 was determined to be greater than 2000 mg/kg; further low cytotoxicity in RAW cells was also observed. Overall, this work shows that the methanolic crude extract and fractions, mainly F2, of Uvaria comperei stem have interesting anti-inflammatory properties.

Secondary metabolites from an endophytic fungus Trichoderma erinaceum with antimicrobial activity towards Pythium ultimum.

Chemical investigation of the endophytic fungus, Trichoderma erinaceum, isolated from healthy and asymptomatic common bean field crop, resulted in the isolation of a new alkene, (Z)-5-amino-5-(1,1,2-trihydroxybuta-1,3-dienyloxy)pentane-6,7,8,9-tetraol (1), together with five known compounds (2-6). The structures of the compounds were elucidated by analysis of their spectroscopic data including 1 D, 2 D NMR, ESI-HRMS and literature data. The organic crude extract and the compound isolated from T. erinaceum significantly (p ≤ 0.05) inhibited the mycelial growth of Pythium ultimum.

Antifungal potential of extracts, fractions and compounds from Uvaria comperei (Annonaceae) and Oxyanthus unilocularis (Rubiaceae).

Phytochemical study of Uvaria comperei afforded an alkaloid, 8,9-dimethoxy-5H-phenanthridin-6-one (1), isolated and characterised (assignment of 1H and 13C NMR) for the first time from a natural source along with two flavonoids, (2S)-5-hydroxy-7,8-dimethoxyflavanone (2) and (2S)-7-hydroxy-5-methoxy-6,8-dimethylflavone (3). Clethric acid (4), oleanoic acid (5), ß-sitosterol 3-O-ß-D-glucopyranoside (9), ß-sitosterol palmitate (6) and a mixture of stigmasterol (7) and ß-sitosterol (8) were isolated from Oxyanthus unilocularis. The structures of these compounds were elucidated using modern spectroscopic techniques including1D and 2D Nuclear Magnetic Resonance (NMR) Spectroscopy (1H, 13C, 1H-1H COSY, HSQC, HMBC) and Mass Spectrometry. Some fractions and compounds from Uvaria comperei exhibited good antifungal activity against clinical isolates and standard strains of yeast species of Candida and Cryptococcus genera while extracts from Oxyanthus unilocularis displayed weak antifungal activity. The results obtained show that Uvaria comperei could be a potential source of antifungal drugs.

Involvement of lytic enzymes and secondary metabolites produced by Trichoderma spp. in the biological control of Pythium myriotylum.

This investigation was aimed to evaluate the antimicrobial activities and involvement of extracellular lytic enzymes produced by four strains of Trichoderma in the inhibition of Pythium myriotylum. Antagonistic effects were tested by dual culture. Activities of lytic enzymes were evaluated from the filtrate of each strain after cultivation in selected media. Organic extracts were obtained from liquid media subsequent to the cultivation of Trichoderma in potato dextrose broth (PDB). Non-volatile organic compounds such as polyphenols and flavonoids were evaluated spectrophotometrically while volatile organic compounds (VOCs) were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The antimicrobial activity of the organic extracts was determined using the poisoning method. Results have shown that all the strains were antagonists against P. myriotylum. T. erinaceum (IT-58), T. gamsii (IT-62), T. afroharzianum (P8), and T. harzianum (P11) that were found to produce cellulase, protease, and xylanase. Over 20 compounds were identified in each extract, including esters, lactones, and organic acids. The organic extracts also contained high amounts of polyphenolic compounds and flavonoids and significantly inhibited the mycelial growth of P. myriotylum. The minimal inhibition concentrations were 80 µg/µL, 40 µg/µL, 20 µg/µL, and 10 µg/µL, for extracts obtained from T. erinaceum (IT-58), T. gamsii (IT-62), T. afroharzianum (P8), and T. harzianum (P11), respectively. There was significant correlation between the production of total polyphenol and flavonoid content and the antagonistic effects of the tested strains.

Cameroonian medicinal plants belonging to Annonaceae family: radical scavenging and antifungal activities.

The free-radical scavenging activity of ethanolic and methanolic extracts of leaves, stems and roots of Annona muricata, Monodora tenuifolia, Uvaria comperei, Uvaria muricata and Xylopia africana was evaluated using DPPH and ORAC assays. Further, phytochemical analysis, total phenolic and total flavonoid contents were also determined. Moreover, the antifungal activity of extracts was studied. The findings indicated that A. muricata and U. comperei extracts own antiradical activities and moderate antifungal properties.

Using Citrus aurantifolia essential oil for the potential biocontrol of Colocasia esculenta (taro) leaf blight caused by Phytophthora colocasiae.

The aim of this work was to evaluate the antimicrobial activities of leaves and epicarp of Citrus aurantifolia essential oil against Phytophthora colocasiae, the causative agent of taro leaf blight. Oils were extracted by hydrodistillation, and their chemical composition was determined by gas chromatography and gas chromatography coupled with mass spectrometry. Antimicrobial activities of oils were tested in vitro against mycelium growth and sporangium production. In situ tests were done on healthy taro leaves, and the necrosis symptoms were evaluated. Results showed that the essential oil extraction yields from leaves and epicarp were 0.61 and 0.36%, respectively. Limonene (48.96%), bornyl acetate (14.18%), geraniol (10.53%), geranial (3.93%), and myrcene (3.14%) were the main components in leaf oil, while limonene (59.09%), cis-hydrate sabinene (7.53%), geranial (5.61%), myrtenol (5.02%), and terpinen-4-ol (3.48%) were the main components in epicarp oil. Both oils exhibited antimicrobial activities with total inhibition of the mycelium growth at 500 and 900 ppm for leaf and epicarp, respectively. The highest inhibitory concentration of sporangium production was 400 (72.84%) and 800 ppm (80.65%) for leaf and epicarp oil, respectively. For the standard fungicide (metalaxyl), the total inhibition value of mycelial growth and sporangium production was 750 ppm. In situ tests showed that, at 5000 ppm, total inhibition (100%) was obtained for a preventive test, while 50% of the inhibition was observed for a curative test when leaf oil was applied. When epicarp essential oil was applied at 5000 ppm, 47.5 and 16.66% of the reduction of leaf necrosis were observed for the preventive and curative test, respectively. There were positive correlations between both the oil concentration and the reduction of necrosis caused by P. colocasiae. These findings suggest that the C. aurantifolia essential oil could serve as an eco-friendly biocontrol for the management of taro leaf blight.

[Iodine levels in food and soil in different regions in Cameroon]. / Evaluation de la teneur en iode des aliments et du sol de certaines régions du Cameroun.

Iodine deficiency diseases (IDD) are a public health problem in many developing countries, such as Cameroon. They are often the consequence of insufficient iodine intake and/or the effect of thiocyanate in foods such as cassava; this chemical inhibits iodine fixation by the thyroid gland. One method of combatting these diseases is to counsel and encourage the consumptions of iodine-rich foods. We accordingly undertook an evaluation of the iodine content of staple foods, the soil, and the salt in some zones of western Cameroon and in the capital. Food (63), salt (04) and soil (05) samples were collected in four villages of western Cameroon, and food (20), water (18) and salt samples (14) were collected in Yaoundé (central province). Iodine content in foods and soils was assessed by the catalytic destructive testing of thiocyanate by nitrate in the presence of iodine. Iodine content in water was determined colorimetrically after mineralization and in salt by volumetric methods. Results show that iodine levels in salt depend on its origin, but was much lower than the 50-100 ppm recommended by the WHO. Soil and water levels depended on the stream and the origin. Several of the more than 20 foods sampled from Yaoundé had iodine concentrations higher than 10 microg/100 g: plantain (22.5 microg/100 g), wheat flour (21 microg/100 g), corn flour (17.75 microg/100 g), groundnuts (12.5 microg/100 g), sweet potatoes (12.25 microg/100 g), zoom (11.34 microg/100 g) and rice (10.45 microg /100 g). In western villages, we noted that iodine levels in food crops depended on the soil levels. Nevertheless, it was high in cocoyam (79.5 microg/100 g), yarns (68 microg/100 g), potatoes (62 microg/100 g), plantains (58.15 microg/100 g), and red beans (53.93 microg/100 g). In general, these crops contain more iodine than the food in Yaoundé; these results can be used to combat IDD, especially among young children, teenagers and pregnant women.