Antimicrobial diterpenoids and triterpenoids from the stem bark of Croton macrostachys

Antimicrobial-guided fractionation of the EtOAc extract of the stem bark of Croton macrostachys afforded five known compounds including two lupane triterpenoids, lupeol (1) and betulin (2), and three clerodane diterpenoids, floridolide A (3), hardwickic acid (4) and 12-oxo-hardwickic acid (5). Their structures were elucidated on the basis of spectral studies and comparison with published data. The EtOAc extract and compounds 1, 2, 4 and 5 were evaluated for their antibacterial and antifungal activities by macro-dilutionmethod. The extract displayed significant antibacterial and antifungal activities (MIC = 31.25-1000 μg/ml). Betulin (2) and 12-oxo-hardwickic acid (5) were the most active compounds (MIC = 7.81-500 μg/ml). Themost sensitive microorganisms were Staphylococcus aureus ATCC 25922 for bacteria and two Candida species, Candida albicans ATCC 24433 and Candida krusei ATCC 6258, for fungi. The isolation of these active antibacterial and antifungal principles supports the use of C. macrostachys in traditional medicine for the treatment of microbial infections.Keywords: Croton macrostachys; Euphorbiaceae; triterpenes; diterpenes; antibacterial; antifungal

The assessment of risk factors, lipid profile, uric acid and alanine aminotransferase in Helicobacter pylori-positive subjects

Background: Helicobacter pylori infection is associated with gastro duodenal ulcer, chronic gastric, MALT lymphoma and gastric cancer but also to coronary heart diseases, ischemic diseases and metabolic diseases like diabetes. The colonization of the stomach by H. pylori causes persistent inflammation of the stomach wall which can influence some biochemical parameters in the patient. The aim of this study was to investigate risk factors, uric acid and alanine aminotransferase along with lipid parameters in H. pylori-positive and -negative patients at Dschang District Hospital in Cameroon.Methods: A cross-sectional study was carried out on 160 consenting patients of average age 53.91±13.36 years attending the hospital for medical check-up or admitted in the hospital. The determination of anti-H. pylori IgG by the indirect enzyme-linked immunosorbent assay (ELISA) technique, enabled us to distinguish two groups of patients. A questionnaire survey was administered to study participants and potential risk factors for H. pylori exposure sought. Measurements of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid and activity of alanine aminotransferase were carried out in serum by methods resulting from commercial kits.Results: The habits of not washing hands after the toilets (OR = 3.33; p = 0.036) and giving of chewed food by the parents to children (OR = 2.26; p = 0.029) were independent risk factors of H. pylori infection. H. pylori infected patients had increased levels of uric acid (p = 0.017), total cholesterol (p = 0.001), LDL-cholesterol (p = 0.021) and total cholesterol/HDL-cholesterol ratio (p = 0.046) compared to the uninfected group.Conclusions: Our study therefore suggests that H. pylori infection can cause modifications of lipid parameters and uremia that are considered as risk factors for cardiovascular diseases and gout.

Antimicrobial and antioxidant activity of kaempferol rhamnoside derivatives from Bryophyllum pinnatum

Abstract Background Bryophyllum pinnatum (Lank.) Oken (Crassulaceae) is a perennial succulent herb widely used in traditional medicine to treat many ailments. Its wide range of uses in folk medicine justifies its being called "life plant" or "resurrection plant", prompting researchers' interest. We describe here the isolation and structure elucidation of antimicrobial and/or antioxidant components from the EtOAc extract of B. pinnatum. Results The methanol extract displayed both antimicrobial activities with minimum inhibitory concentration (MIC) values ranging from 32 to 512 μg/ml and antioxidant property with an IC50 value of 52.48 μg/ml. Its partition enhanced the antimicrobial activity in EtOAc extract (MIC = 16-128 μg/ml) and reduced it in hexane extract (MIC = 256-1024 μg/ml). In addition, this process reduced the antioxidant activity in EtOAc and hexane extracts with IC50 values of 78.11 and 90.04 μg/ml respectively. Fractionation of EtOAc extract gave seven kaempferol rhamnosides, including; kaempferitrin (1), kaempferol 3-O-α-L-(2-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (2), kaempferol 3-O-α-L-(3-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (3), kaempferol 3-O-α-L-(4-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (4), kaempferol 3-O-α-D- glucopyranoside-7-O-α-L-rhamnopyranoside (5), afzelin (6) and α-rhamnoisorobin (7). All these compounds, except 6 were isolated from this plant for the first time. Compound 7 was the most active, with MIC values ranging from 1 to 2 μg/ml and its antioxidant activity (IC50 = 0.71 μg/ml) was higher than that of the reference drug (IC50 = 0.96 μg/ml). Conclusion These findings demonstrate that Bryophyllum pinnatum and some of its isolated compounds have interesting antimicrobial and antioxidant properties, and therefore confirming the traditional use of B. pinnatum in the treatment of infectious and free radical damages.</p

Anticancer and antibacterial secondary metabolites from the endophytic fungus Penicillium sp. CAM64 against multi-drug resistant Gram-negative bacteria.

Background: The emergence of multiple-drug resistance bacteria has become a major threat and thus calls for an urgent need to search for new effective and safe anti-bacterial agents. Objectives: This study aims to evaluate the anticancer and antibacterial activities of secondary metabolites from Penicillium sp. , an endophytic fungus associated with leaves of Garcinia nobilis . Methods: The culture filtrate from the fermentation of Penicillium sp. was extracted and analyzed by liquid chromatography\u2013 mass spectrometry, and the major metabolites were isolated and identified by spectroscopic analyses and by comparison with published data. The antibacterial activity of the compounds was assessed by broth microdilution method while the anticancer activity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: The fractionation of the crude extract afforded penialidin A-C (1-3), citromycetin (4), p-hydroxyphenylglyoxalaldoxime (5) and brefelfin A (6). All of the compounds tested here showed antibacterial activity (MIC = 0.50 \u2013 128 \u3bcg/mL) against Gramnegative multi-drug resistance bacteria, Vibrio cholerae (causative agent of dreadful disease cholera) and Shigella flexneri (causative agent of shigellosis), as well as the significant anticancer activity (LC50 = 0.88 \u2013 9.21 \u3bcg/mL) against HeLa cells. Conclusion: The results obtained indicate that compounds 1-6 showed good antibacterial and anticancer activities with no toxicity to human red blood cells and normal Vero cells

Antibacterial and dermal toxicological profiles of ethyl acetate extract from Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae)

<p>Abstract</p> <p>Background</p> <p>The emergence in recent years of numerous resistant strains of pathogenic bacteria to a range of formerly efficient antibiotics constitutes a serious threat to public health. <it>Crassocephalum bauchiense</it>, a medicinal herb found in the West Region of Cameroon is used to treat gastrointestinal infections as well as liver disorders. The ethyl acetate extract from the leaves of <it>C. bauchiense </it>was evaluated for its antibacterial activity as well as acute and sub-acute toxicities.</p> <p>Methods</p> <p>The plant extract was prepared by maceration in ethyl acetate. Its phytochemical screening was done by standard methods. The broth microdilution method was used to evaluate the <it>in vitro </it>antibacterial activity. The <it>in vivo </it>antibacterial activity of a gel formulation (0.05, 1 and 2% w/v) of this extract was evaluated using a <it>Staphylococcus aureus</it>-induced dermatitis in a murine model. Selected haematological and biochemical parameters were used to evaluate the dermal sub-acute toxicity of the extract in rats.</p> <p>Results</p> <p>Phytochemical screening of the <it>C. bauchiense </it>extract revealed the presence of alkaloids, phenols, tannins and sterols. <it>In vitro </it>antibacterial activities were observed against all the tested microorganisms (MIC = 0.04-6.25 mg/ml). Formulated extract-gel (2% w/v) and gentamycin (reference drug) eradicated the microbial infection after five days of treatment. A single dermal dose of this extract up to 32 g/kg body weight (bw) did not produce any visible sign of toxicity. Also, daily dermal application of the <it>C. bauchiense </it>extract gel formulation for 28 days did not show any negative effect, instead some biochemical parameters such as alanine aminotransferase (ALT and AST), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides were significantly (p < 0.05) affected positively.</p> <p>Conclusion</p> <p>These results indicate that the <it>C. bauchiense </it>ethyl acetate extract can be used safely for the treatment of some bacterial infections.</p

Ethnobotany and antimicrobial peptide from plants of Solanaceae family: An update and future prospect

The Solanaceae is an important plant family that has been playing an essential role in traditional medicine and human nutrition. Members of the Solanaceae are rich in bioactive metabolites and have been used by different tribes around the world for ages. Antimicrobial peptides (AMPs) from plants have drawn great interest in recent years and raised new hope for developing new antimicrobial agents for meeting the challenges of antibiotic resistance. This review aims to summarize the reported AMPs from plants of the Solanaceae with possible molecular mechanisms of action as well as to correlate their traditional uses with reported antimicrobial actions of the peptides. A systematic literature study was conducted using different databases until August 2019 based on the inclusion and exclusion criteria. According to literature, a variety of AMPs including defensins, protease inhibitor, lectins, thionin-like peptides, vicilin-like peptides, and snaking were isolated from plants of the Solanaceae and were involved in their defense mechanism. These peptides exhibited significant antibacterial, antifungal and antiviral activity against organisms for both plant and human host. Brugmansia, Capsicum, Datura, Nicotiana, Salpichora, Solanum, Petunia, and Withania are the most commonly studied genera for AMPs. Among these genera, Capsicum and the Solanum ranked top according to the total number of studies (35%–38% studies) for different AMPs. The mechanisms of action of the reported AMPs from Solanaceae was not any new rather similar to other reported AMPs including alteration of membrane potential and permeability, membrane pore formation, and cell aggregation. Whereas, induction of cell membrane permiabilization, inhibition of germination and alteration of hyphal growth were reported as mechanisms of antifungal activity. Plants of the Solanaceae have been used traditionally as antimicrobial, insecticidal, and antiinfectious agents, and as poisons. The reported AMPs from the Solanaceae are the products of chemical shields to protect plants from microorganisms and pests which unfold an obvious link with their traditional medicinal use. In summary, it is evident that AMPs from this family possess considerable antimicrobial activity against a wide range of bacterial and fungal pathogens and can be regarded as a potential source for lead molecules to develop new antimicrobial agents

Antimicrobial clerodane diterpenoids from Microglossa angolensis Oliv. et Hiern

Objective: To identify the antimicrobial components present in Microglossa angolensis following fractionation of the methylene chloride extract of the aerial part of this plant. Materials and Methods: The plant was dried and extracted by percolation with methylene chloride. The dry extract was fractionated and purified by silica gel column chromatography. The isolated compounds were identified by comparison of their Nuclear Magnetic Resonance (NMR) spectral data with those reported in the literature. Antimicrobial activity was assayed by broth macro dilution method. Results: The crude extract of M. angolensis displayed significant antifungal and antibacterial activities (MIC = 312.50-1250µg/ml). 6β-(2-methylbut-2(Z)-enoyl)-3α,4α,15,16-bis-epoxy-8β,10βH-ent-cleroda-13(16),14-dien-20,12-olide and spinasterol were the most active compounds (MIC = 1.56-100µg/ml) and the most sensitive microorganisms were Enterococcus faecalis and Candida tropicalis for bacteria and yeasts respectively. Conclusion: The isolation of these active antibacterial and antifungal principles supports the use of M. angolensis in traditional medicine for the treatment of gastro-intestinal disorders

Antibacterial and antioxidant activities of extracts and some flavonoids from the leaves of Clerodendrum buchholzii Gurke (Verbenaceae)

Morbidity and mortality due to diarrhoea continues to be a major problem in many developing countries. The most common microorganisms responsible for diarrhoeal diseases are Vibrio cholerae, Escherichia coli and Shigella spp. The present study aims to evaluate the antibacterial and antioxidant activities of extracts and compounds from the leaves of Clerodendrum buchholzii, a plant traditionally used in the African pharmacopeia for the treatment of furunculosis, echymosis and gastritis. The dried leaves were macerated in methanol (MeOH) to afford the crude extract that was extracted with ethyl acetate (EtOAc) and n-butanol (n-BuOH) to obtain EtOAc and n-BuOH extracts, respectively. The column chromatography of EtOAc and n-BuOH extracts followed by purification of different fractions led to the isolation of four known flavonoids [acacetin 7-O-β-D-glucoside (1), kaempferol 7-O-β-D-glucoside (2), acacetin (3) and apigenin (4)]. Structures of isolated compounds were assigned on the basis of spectroscopic analysis, and by comparison of our data with those of the literature. The antioxidant activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and gallic acid equivalent antioxidant capacity (GEAC) assays. The antibacterial activity was assessed using broth microdilution method by performing minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) against the strains of Gram-positive bacterium, Staphylococcus aureus (a major cause of community and hospital-associated infection), and Gram-negative multi-drug resistant bacteria, Vibrio cholerae (causative agent of cholera) and Shigella flexneri (causative agent of shigellosis). All of the extracts showed different degrees of antioxidant and antibacterial activities. Apigenin (4) obtained from EtOAc extract displayed the largest antibacterial and antioxidant properties which were in some cases equal or higher than those of reference drugs. Our results showed that C. buchholzii has potentials as a natural source of anti-diarrhoeal and free radical scavenging products, and could be given further investigations.Keywords: Clerodendrum buchhlzii, Verbenaceae, Flavonoids, Antibacterial, Antioxidan