Metabolomic profiling and bactericidal effect of Polyalthia longifolia (Sonn.) Twaites. stem bark against methicillin-resistant Staphylococcus aureus.

Objective. The present study was carried out to establish the chemical profile of the methanolic extract of Polyalthia longifolia stem bark and investigate its antibacterial property against some human pathogenic bacteria. Methods. The extract was analysed using liquid and gas chromatography coupled to mass spectrometry. Antibacterial activity of P. longifolia extract against some human pathogenic bacteria was screened using the AlamarBlue method, and MIC and MBC were determined. Results and Conclusion. Liquid chromatography-mass spectrometry (LC-MS) revealed the presence of 21 compounds among which 12 were identified. Gas chromatography-mass spectrometry (GC-MS) allowed identification of 26 compounds, the three major ones being the following: cis vaccenic acid (17.79 %), 3-ethyl-3-hydroxyandrostan-17-one (13.80 %) and copaiferic acid B (12.82 %). P. longifolia extract was active against Gram-positive bacteria with MIC ranging from 1 to 2 mg ml-1 and MBC from 2 to 6 mg ml-1. This study demonstrated the bactericidal effect of the methanolic extract of Polyalthia longifolia stem bark against some human pathogenic bacteria, including methicillin-resistant S. aureus . This effect could be related to the presence in the extract of a broad diversity of well-known compounds with established pharmacological properties. These results support the ethnomedicinal use of P. longifolia stem bark in Cameroon for the management of methicillin-resistant S. aureus (MRSA)-related infections.

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.

Chronic Gastric Ulcer Healing Actions of the Aqueous Extracts of Staple Plant Foods of the North-West, Adamawa, and West Regions of Cameroon.

Aim: This study is aimed at establishing phenolic compound profile and assessing the possible antiulcer activities of aqueous extracts of some staple plant foods from the West and North-West regions of Cameroon against chronic gastric ulcer models in rats. Materials and Methods: Phenolic constituents of extracts were evaluated using HPLC-DAD. Aqueous extracts of Corchorus olitorius, Solanum nigrum, Vigna unguiculata, Triumfetta pentandra, "nkui" spices, and "yellow soup" spices were tested at two doses (200 and 400 mg/kg). After treatments, animals were sacrificed, healing percentage and antioxidant status (catalase, superoxide dismutase, and glutathione peroxidase) were evaluated, and histological examination of gastric mucosa was realized. Results: HPLC-DAD revealed that p-hydroxybenzoic and protocatechuic acids were the phenolic compound present in all extracts. Oral administration of extracts (200 and 400 mg/kg) significantly reduced ulcer surface value and significantly increased mucus production compared to the control groups (p < 0.05). Histological study supported the observed healing activity of different extracts characterized by a reduced inflammatory response. Moreover, administration of aqueous extracts increased the activity of antioxidant enzymes. Conclusion: This study revealed that aqueous extracts of Solanum nigrum, Corchorus olitorius, Vigna unguiculata, Triumfetta pentandra, "yellow soup" spices, and "nkui" spices possess healing antiulcer effects against models of gastric ulcers. The antiulcer mechanisms involved may include increase of gastric mucus production and improvement of the antioxidant activity of gastric tissue. These activities may be due to the phenolic compounds identified in the extracts, especially p-hydroxybenzoic and protocatechuic acids present in all extracts and with known antioxidant, cytoprotective, and healing properties. However, all the diets may promote the healing process of chronic ulcers caused by excessive alcohol consumption/stress.

Antihistaminergic and Anticholinergic Properties of the Root Bark Aqueous Extract of Diospyros mespiliformis (Ebenaceae) on Hypersecretion of Gastric Acid Induced in Wistar Rats.

OBJECTIVE: The objective of this study was to elucidate the antisecretory mechanism of the root bark aqueous extract of Diospyros mespiliformis (RBAEDM) in Wistar rats. Materials and methods. RBAEDM was tested on three experimental animal models of gastric acid hypersecretion including pyloric ligation (PL), PL with histamine, and carbachol pretreatments. The ulcerated surface, mucus mass, pH, gastric acidity, and pepsin activity were determined. Some bioactive compounds revealed by qualitative phytochemistry were quantified. Some markers of oxidative stress in vivo such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and in vitro antioxidant tests (ABTS: 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid, DPPH: 2,2-diphenyl-2-picrylhydrazyl, and FRAP: ferric reducing antioxidant power) were determined. RESULTS: In the three models studied, RBAEDM resulted in increases in the percentages of inhibition ranging from 9.50 to 59.52% of gastric ulcer and mucus mass. This increase was accompanied by the reduction in acidity and pepsin activity. The administration of RBAEDM resulted in a significant decrease (p < 0.05, p < 0.01) in MDA levels correlated with a significant increase (p < 0.05, p < 0.01) in CAT and nitrite levels compared with the negative control. RBAEDM has the ability to scavenge ABTS and DPPH radicals and to reduce FRAP, and the inhibitory concentration of 50% (IC50) of the ABTS radical was 220 µg/mL compared with the butylhydroxytoluene (BHT) control (175 µg/mL). Quantitative phytochemistry revealed abundant polyphenols, flavonoids, tannins, saponins, and anthocyanin. CONCLUSION: RBAEDM protected gastric mucous membrane for gastric acid by mechanisms that would involve both anticholinergic and antihistaminergic pathways.

Eremomastax speciosa (Hochst.) Cufod. counteracts the delaying effect of indomethacin on Helicobacter pylori-associated chronic gastric ulcers healing.

ETHNOPHARMACOLOGICAL RELEVANCE: Information collected from local traditional healers reported that Eremomastax speciosa (Hochst.) Cufod. has for a long time been used to manage gastric ulcers in many regions of Cameroon and beyond. This traditional use is supported by numerous studies. However, efficacy of this plant has never been tested in case of chronic gastric ulcers associating Helicobacter pylori infection. AIM OF THE STUDY: This study was designed to investigate curative effects of the aqueous extract of E. speciosa leaves (AEESL) against chronic gastric ulcers associated to Helicobacter pylori infection. MATERIALS AND METHODS: Two experimental methods of chronic gastric ulcers, involving H. pylori infection, were performed using Wistar rats, namely: acetic acid-induced ulcers and "unhealed ulcers". E. speciosa extract was tested at three doses (100; 200; 400 mg/kg) and at the end of experiments, some in vivo antioxidant parameters were measured, bacterial load in stomach tissue calculated and histopathological examinations performed. RESULTS: E. speciosa reduced ulcer index at all the doses and significantly increased mucus production as well as antioxidant (mainly SOD and GSH) level. Bacterial load in stomach significantly decreased (p < 0.05) in extract-treated groups (200 and 400 mg/kg) as confirmed by histopathological observations. The extract was found to be non toxic to healthy and cancerous cells (IC50 > 1000 µg/mL). CONCLUSIONS: E. speciosa accelerated healing of gastric ulcers even in presence of indomethacin, while decreasing bacterial loads in rats' stomachs. These results provide supplementary support to the use of E. speciosa in ethnomedicine and open new perspectives regarding development of a herbal-based monotherapy able to efficiently replace/supplement standard antiulcer tri/quadritherapy.