As the search for new antibiotics continues, the resistance to known antimicrobial compounds continues to increase. Many researchers around the world, in response to antibiotics resistance, have continued to search for new antimicrobial compounds in different ecological niches such as the marine environment. Marine habitats are one of the known and promising sources for bioactive compounds with antimicrobial potentials against currently drug-resistant strains of pathogenic microorganisms. For more than a decade, numerous antimicrobial compounds have been discovered from marine environments, with many more antimicrobials still being discovered every year. So far, only very few compounds are in preclinical and clinical trials. Research in marine natural products has resulted in the isolation and identification of numerous diverse and novel chemical compounds with potency against even drug-resistant pathogens. Some of these compounds, which mainly came from marine bacteria and fungi, have been classified into alkaloids, lactones, phenols, quinones, tannins, terpenes, glycosides, halogenated, polyketides, xanthones, macrocycles, peptides, and fatty acids. All these are geared towards discovering and isolating unique compounds with therapeutic potential, especially against multidrug-resistant pathogenic microorganisms. In this review, we tried to summarize published articles from 2015 to 2019 on antimicrobial compounds isolated from marine sources, including some of their chemical structures and tests performed against drug-resistant pathogens.

Background Malaria and neglected communicable protozoa parasitic diseases, such as leishmaniasis, and trypanosomiasis, are among the otherwise called diseases for neglected communities, which are habitual in underprivileged populations in developing tropical and subtropical regions of Africa, Asia, and the Americas. Some of the currently available therapeutic drugs have some limitations such as toxicity and questionable efficacy and long treatment period, which have encouraged resistance. These have prompted many researchers to focus on finding new drugs that are safe, effective, and affordable from marine environments. The aim of this review was to show the diversity, structural scaffolds, in-vitro or in-vivo efficacy, and recent progress made in the discovery/isolation of marine natural products (MNPs) with potent bioactivity against malaria, leishmaniasis, and trypanosomiasis. Main text We searched PubMed and Google scholar using Boolean Operators (AND, OR, and NOT) and the combination of related terms for articles on marine natural products (MNPs) discovery published only in English language from January 2016 to June 2020. Twenty nine articles reported the isolation, identification and antiparasitic activity of the isolated compounds from marine environment. A total of 125 compounds were reported to have been isolated, out of which 45 were newly isolated compounds. These compounds were all isolated from bacteria, a fungus, sponges, algae, a bryozoan, cnidarians and soft corals. In recent years, great progress is being made on anti-malarial drug discovery from marine organisms with the isolation of these potent compounds. Comparably, some of these promising antikinetoplastid MNPs have potency better or similar to conventional drugs and could be developed as both antileishmanial and antitrypanosomal drugs. However, very few of these MNPs have a pharmaceutical destiny due to lack of the following: sustainable production of the bioactive compounds, standard efficient screening methods, knowledge of the mechanism of action, partnerships between researchers and pharmaceutical industries. Conclusions It is crystal clear that marine organisms are a rich source of antiparasitic compounds, such as alkaloids, terpenoids, peptides, polyketides, terpene, coumarins, steroids, fatty acid derivatives, and lactones. The current and future technological innovation in natural products drug discovery will bolster the drug armamentarium for malaria and neglected tropical diseases.

Background. The stem bark decoction of Stemonocoleus micranthus Harms (Fabaceae) is most widely used traditionally as a remedy for various diseases such as malaria and boil. In this study, the anti-inflammatory and immunomodulatory activities of the methanol-dichloromethane extract (MDE) from the stem bark of the plant in rodents were evaluated. Methods. The carrageenan-induced rat paw oedema, cotton pellet-induced granuloma in rat, and xylene-induced ear oedema in mice were used to study the anti-inflammatory activity of methanol-dichloromethane extract of Stemonocoleus micranthus (MDESm) (100, 200, and 400 mg/kg). The effects of MDESm (100, 200, and 400 mg/kg) on cyclophosphamide-induced immunosuppression, neutrophil adhesion, carbon clearance, and haematological and biochemical parameters were carried out to study its immunomodulatory activity in mice. Result. MDESm (100 mg/kg, p.o.) significantly (p<0.05) inhibited carrageenan-induced oedema by 57.1% at 5th h posttreatment compared with control. At 100 mg/kg, p.o., MDESm significantly (p<0.05) reduced cotton pellet-induced granuloma by 39.28% and nonsignificantly reduced xylene-induced ear oedema by 34.1%. Treatment with MDESm (100 and 400 mg/kg) nonsignificantly abolished the neutropenia caused by cyclophosphamide with a percentage neutrophil reduction of 0 and −14.86%, respectively, while MDESm (200 mg/kg) and levamisole (50 mg/kg) had a nonsignificant reduction in neutrophil count (10.16 and 31.40%), respectively, all compared to the distilled water-treated group with a neutrophil count of −9.82%. MDESm at doses of 100 and 200 mg/kg increased phagocytic index by 0.0447 ± 0.00762 and 0.0466 ± 0.00703, respectively, although not significantly when compared to the control group with a value of 0.0226 ± 0.02117. There was a decrease in WBC and lymphocyte counts in MDESm- (200 mg/kg) treated group, suggesting immunosuppressive potential at this dose. MDESm caused a dose-dependent decrease in ALT and core liver enzymes, suggesting a hepatoprotective effect. The acute toxicity test revealed that MDESm is safe in mice with an oral lethal dose (LD50) of >5 g/kg. Conclusion. The methanol-dichloromethane extract of Stemonocoleus micranthus Harms possesses mild anti-inflammatory and immunomodulatory activities which may be more pronounced upon fractionation and purification. Therefore, more investigations are needed to explore these activities further.

Objective: This study aimed to detect and compare the frequency and antibiotics resistant pattern of Gram-negative uropathogens implicated in urinary tract infections (UTIs) in paediatric patients attending some hospitals in Nigeria and to proffer recommendations for its management. Methods: Based on standard procedures, midstream urine samples were collected. Urinalysis was done as a preliminary diagnosis of UTI using Combi-9 test strip. Isolation of uropathogen was done and antibiotic sensitivity test was carried out using Kirby-Bauer technique. Results: Out of 489 samples collected, 130 (26.4%) was positive for UTI. The prevalence rate of UTI in the investigated areas such as Nsukka, Otukpo, Gboko and Kastina Ala was 31.8%, 17.5%, 34.3% and 17.1%, respectively. The prevalence of UTI was higher in males 81 (30.9%) than in females 49 (21.6%), but there was no statistically significant association between gender and UTI (p = 0.636). The prevalence of UTI was greater among the age of 2 -5 years (28.2%) and decreased with the increase in age, although there was no significant association between UTI and the age groups (p = 0.870). Generally, Klebsiella pneumonae (88.8%) was the most dominant bacterium (it was even more in males), followed by E. coli (40.6%), which was more in females, then Pseudomonas spp. (45.0%) and Proteus mirabilis (13.8%). The in-vitro antibiotic susceptibility testing shows that the isolate was highly resistant to Augmentin, Cotrimoxazoel, Amoxicilin and Tetracycline, while some of the isolate shows intermediate resistant to Nitrofurantoin and Nalixidic acid. Ofloxacine and Gentamicin were the most effective antibiotics against the isolates from all the study areas.

Introduction: Lannea barteri is used in the folkloric treatment of many disease states ranging from epilepsy, diarrhoea, oedema and ulcers, etc. This study investigated the antioxidant and hepatoprotective potentials of methanol (MFLB), n-hexane (nHFLB) and ethyl acetate (EFLB) leaf fractions of L. barteri and identified the active metabolites. Materials and methods: The in vitro models used were 1, 1-diphenyl-1-picrylhydrazyl (DPPH), reducing power and thiobarbituric acid assays while in the in vivo model, carbon tetrachloride-induced oxidative liver damage in albino rats was used, and the biomarkers assayed were aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), malondialdehyde (MDA), serum total protein, serum direct and total bilirubin. Also, histopathological examination of the liver, high performance liquid chromatography (HPLC) profiling and liquid chromatography-mass spectroscopy-electrospray ionization (LC-MS-ESI) analysis of the fractions were done. Results: In the in vitro assays, the decreasing order of DPPH free radical scavenging activity of the ascorbic acid and fractions at 400 μg/ml is as follows: ascorbic acid (86.6%), MFLB (52.8%), EFLB (36.6%), and nHFLB (28.1%). The percentage scavenging activity of the samples at 400 μg/ml in the TBA followed this pattern: ascorbic acid (117.1%), MFLB (82.2%), nHFLB (80.0%), and EFLB (46.9%). The ascorbic acid elicited highest reducing power (42.6%), followed by MFLB (22.5%), nHFLB (13.7%), and EFLB (-0.93%). The in vivo study showed significant (p < 0.0001) reduction in serum AST, ALT, and direct bilirubin with a non-significant reduction in ALP, total bilirubin and MDA, and mild elevation in total protein. Histopathological studies revealed a restorative effect on liver architecture. The phytochemical analyses revealed the presence of resins, terpenoids, flavonoids, carbohydrates, alkaloids, reducing sugar, saponins, tannins and proteins. HPLC-ESI-MS analysis revealed the presence of potentially bioactive compounds in L. barteri fractions. Conclusion:The fractions from L. barteri leaf possessed in vitro antioxidant and hepatoprotective potentials against CCl 4 -hepatic oxidative damage; therefore, proper isolation and characterization of these identified bioactive compounds responsible for the observed effects are ongoing.

Secondary metabolites from marine sources have a wide range of biological activity. Marine natural products are promising candidates for lead pharmacological compounds to treat diseases that plague humans, including cancer. Cancer is a life-threatening disorder that has been difficult to overcome. It is a long-term illness that affects both young and old people. In recent years, significant attempts have been made to identify new anticancer drugs, as the existing drugs have been useless due to resistance of the malignant cells. Natural products derived from marine sources have been tested for their anticancer activity using a variety of cancer cell lines derived from humans and other sources, some of which have already been approved for clinical use, while some others are still being tested. These compounds can assault cancer cells via a variety of mechanisms, but certain cancer cells are resistant to them. As a result, the goal of this review was to look into the anticancer potential of marine natural products or their derivatives that were isolated from January 2019 to March 2020, in cancer cell lines, with a focus on the class and type of isolated compounds, source and location of isolation, cancer cell line type, and potency (IC50 values) of the isolated compounds that could be a guide for drug development.

The unpurified enzyme gave specific activity of 51.36 μ/mg and thereafter it was subjected to two phases of purification process of salt precipitation and gel filtration. The precipitating agent was ammonium sulphate while Sephadex-G100 served as purification matrix. The purification fold achieved after precipitation and filtration was 3.3 and with corresponding specific activities of 34.22 μ/mg and 116.31 μ/mg. The substrate used for the assay was o-dianisidine. Within 40-80°C of temperature, the kinetics of the peroxidase inactivation was evaluated. The results from assays showed that cucumber peroxidase conformed to the hypothesis of  Michealis-Menten Theory. From the Lineweaver-Burk plot, Michaelis Constant (Km) and maximum velocity (Vmax) were evaluated and  obtained 5.02mg/ml and 11.57μmol/min respectively. The heat induced inactivation gave biphasic curves, where initial rise in temperature was rapidly succeeded with much slower decrease. A first-order kinetic behaviour was observed for cucumber peroxidase heat inactivation. The k values of between 3.49×10-2 to 8.38×10-2 min-1 was obtained while the Z value was found to be 22.3°C. Decrease in k values with rise in temperature suggests that cucumber peroxidase was rapidly inactivated at elevated temperature. The slope of Arrhenius plot gave the activation energy of 127.99KJMol-1K-1. Also evaluated were thermodynamic constants (ΔH, G Δ, ΔS) for inactivation of peroxidase at variable temperatures. Cucumber peroxidase activity was observed to be pH sensitive and stable within pH range of 5.6-8. Further decrease or increase from this range resulted to decrease in peroxidase stability.