Essential Oils from the Fruits and Leaves of Spondias mombin Linn.: Chemical Composition, Biological Activity, and Molecular Docking Study.

This work focused on characterizing the chemical constituents and evaluating the antioxidant and antimicrobial activities of the essential oils obtained from the fruit and leaves of Spondias mombin-a flowering plant of the Anacardiaceae family. Essential oils were extracted through steam distillation and characterized by gas chromatography-mass spectrometry. For the fruit essential oil, 35 compounds were obtained, and 25 compounds were identified in the leaf essential oil. The dominant compounds present in the fruit essential oil were (E)-ethyl cinnamate (14.06%) and benzyl benzoate (12.27%). Methyl salicylate (13.05%) and heptacosane (12.69%) were the abundant compounds in the leaf essential oil. The antioxidant activity of the essential oils was evaluated via phosphomolybdenum, hydrogen peroxide scavenging, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, and thiobarbituric acid reactive substances (TBARS) assays. The total antioxidant capacity of fruit and leaf essential oils was 48.5 ± 0.7 µg/gAAE and 48.5 ± 0.7 µg/g AAE, respectively. The half maximal scavenging concentrations of the essential oils in the hydrogen peroxide; DPPH and TBARS assays ranged from 252.2 µg/mL to 2288 µg/mL. The antimicrobial activity of the essential oils was tested using broth dilution and disc diffusion assays against eight microorganisms. The essential oils exhibited broad-spectrum antimicrobial activity against the microorganisms with minimum inhibitory concentrations of 9.75-50 mg/mL. Also, the zones of inhibition of the oils ranged from 12 mm to 25 mm. The biofilm inhibitory activities of the oils were dose-dependent with BIC50 values of 42.49 ± 0.1 mg/mL and 97.34 ± 0.6 mg/mL for fruit and leaf essential oils, respectively. Molecular docking studies revealed that the antibiofilm action of the fruit and leaf essential oils could be due to inhibition of the quorum sensing protein, LasR. The results suggest a possible application of the oils as antioxidant and antimicrobial agents.

Clinical characteristics of external bacterial ocular and periocular infections and their antimicrobial treatment patterns among a Ghanaian ophthalmic population.

Empirical antimicrobial therapy is linked to a surge in antimicrobial resistant infections. However, an insight on the bacteria etiology of ocular infections is essential in the appropriation of choice of antimicrobial among clinicians, yet there remains a dearth of data from Ghana. We investigated the bacteria etiology of external ocular and periocular infections and antimicrobial treatment patterns among a Ghanaian ophthalmic population. A multicenter study design with purposive sampling approach was employed. Patients demographics and clinical data were collated using a pretested structure questionnaire. Cornea specimens and conjunctival swabs were obtained for bacterial isolation following standard protocols. About 95% (98/103) of ocular samples were positive for bacteria culture. The proportion of Gram-negative bacteria was 58.2%, and the predominant bacteria species were Pseudomonas aeruginosa 38.8% and Staphylococcus aureus 27.6%. Conjunctivitis 40.0% and keratitis 75.0% were mostly caused by Pseudomonas aeruginosa. The routinely administered antimicrobial therapy were polymyxin B 41.2%, neomycin 35.1% and ciprofloxacin 31.6%. Participants demographic and clinical characteristics were unrelated with positive bacteria culture (p > 0.05). Our results showed a markedly high burden of ocular bacterial infections and variations in etiology. Bacterial infection-control and antimicrobial agent management programs should be urgently institutionalized to prevent the emergence of resistant infections.

In Vivo Antiplasmodial Activity and Toxicological Analyses of the Ethanolic Leaf and Twig Extract of Faurea speciosa Welw. (Proteaceae).

In Africa, medicinal plants are commonly used to treat malaria and other diseased conditions. The ethanolic leaf and twig extract of Faurea speciosa has been shown to possess promising antiplasmodial properties. This present study was aimed at investigating its antiplasmodial effect in vivo. Qualitative phytochemical screening was carried out on the plant samples using standard methods. The antiplasmodial effect against early infection, curative effect against established infection, and prophylactic effect against residual infection were studied in vivo in Plasmodium berghei-infected mice while the carrageenan-induced edema model in chicks was used for anti-inflammatory tests. The phosphomolybdenum and DPPH radical scavenging assays were used in the evaluation of antioxidant potential. Acute toxicity of the extract was evaluated using the Organization for Economic Cooperation and Development (OECD) guidelines. Phytochemical screening of plant samples revealed the presence of flavonoids, coumarins, tannins, saponins, and glycosides. Faurea speciosa leaf and twig extract exhibited significant antiplasmodial activities in the mouse model with parasite suppression rates of 66.63%, 71.70%, and 56.93% in the suppressive, curative, and prophylactic tests, respectively. A 55.50% reduction of edema in the anti-inflammatory test indicated moderate success in reducing inflammation. The total antioxidant capacity of the extract was determined to be 65.4 mg AAE/g of extract, while in the DPPH radical scavenging assay, the IC50 value was found to be 499.4 µg/mL. With the exception of an inconsistent rise in urea level, there was no significant difference in the other biochemistry parameters in the acute toxicity studied. The median lethal dose (LD50) of the extract was over 2000 mg/kg. The results of this study show that Faurea speciosa leaf and twig extract has promising antimalarial capabilities and is fairly safe at low concentrations.

Alkaloids from Cryptolepis sanguinolenta as Potential Inhibitors of SARS-CoV-2 Viral Proteins: An In Silico Study.

The ongoing global pandemic caused by the human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected millions of people and claimed hundreds of thousands of lives. The absence of approved therapeutics to combat this disease threatens the health of all persons on earth and could cause catastrophic damage to society. New drugs are therefore urgently required to bring relief to people everywhere. In addition to repurposing existing drugs, natural products provide an interesting alternative due to their widespread use in all cultures of the world. In this study, alkaloids from Cryptolepis sanguinolenta have been investigated for their ability to inhibit two of the main proteins in SARS-CoV-2, the main protease and the RNA-dependent RNA polymerase, using in silico methods. Molecular docking was used to assess binding potential of the alkaloids to the viral proteins whereas molecular dynamics was used to evaluate stability of the binding event. The results of the study indicate that all 13 alkaloids bind strongly to the main protease and RNA-dependent RNA polymerase with binding energies ranging from -6.7 to -10.6 kcal/mol. In particular, cryptomisrine, cryptospirolepine, cryptoquindoline, and biscryptolepine exhibited very strong inhibitory potential towards both proteins. Results from the molecular dynamics study revealed that a stable protein-ligand complex is formed upon binding. Alkaloids from Cryptolepis sanguinolenta therefore represent a promising class of compounds that could serve as lead compounds in the search for a cure for the corona virus disease.

Antimalarial Efficacy and Toxicological Assessment of Extracts of Some Ghanaian Medicinal Plants.

The economic costs associated with morbidity and mortality due to malaria and malaria associated complications in many sub-Saharan countries and other malaria endemic regions of the world are huge. Reports of emergence of parasite resistance to current malaria drugs have complicated malaria treatment and require the development of new therapeutic agents. The folkloric use of medicinal plants for the management of malaria is well documented. This work evaluated the antiplasmodial activities and toxicity of some medicinal plants used to treat malaria and malaria-like symptoms in Ghana. Plant extracts were obtained by cold maceration in 70% ethanol. Antiplasmodial efficacies were assessed in vitro against 3 strains of Plasmodium falciparum strains (FCM, W2, and CAM06) and in vivo via the 4-day suppressive test in Plasmodium berghei infected mice. Cytotoxicity and acute toxicity were assessed in mammalian cells and mice, respectively. All extracts were active against at least one of the Plasmodium falciparum strains in in vitro evaluations with IC50's in the range of 4-116 µg/mL, whereas Bidens pilosa extracts, with a chemosuppression rate of 75%, was the most active plant in the in vivo experiments. All plant extracts displayed very weak to no cytotoxicity against the mammalian cell line used and exhibited very good selectivity towards the Plasmodium parasites. Syzygium guineense and Parinari congensis extracts were the most toxic in the acute toxicity tests. Altogether, the results indicate that the medicinal plants do possess impressive antiplasmodial properties and provide scientific basis for their use in traditional herbal medicine.