In vivo antimalarial effect of Ananas comosus (L) Merr (Bromeliaceae) fruit peel, and gas chromatography-mass spectroscopy profiling: A possible role for polyunsaturated fatty acid

Purpose: To evaluate the antimalarial effect of Ananas comosus extract and fractions and also to identify the likely bioactive compounds.Method: The fruit peel of the plant was extracted with methanol, and the extract successively fractionated with n-hexane, dichloromethane, ethyl acetate, methanol and water. The n-hexane fraction was further subjected to vacuum liquid chromatography to afford four sub-fractions, one of which was also analyzed using gas chromatography-mass spectroscopy (GC-MS). Plasmodium berghei-infected mice were treated orally with three doses (100, 200 and 400 mg/kg) of the plant extract and a single dose (200 mg/kg) of each of the fractions and sub-fractions in a curative antimalarial model using artemisinin combination therapy (ACT) as the reference drug.Results: The extract exhibited significant (p < 0.001) non-dose dependent parasitemia inhibitory activity in the range of 44.84 to 76.09 %. All fractions displayed inhibitory effect (p < 0.001) in the range of 46.44 to 87.58 % with the dichloromethane fraction displaying the highest effect (87.58 %). The subfractions exhibited significant inhibitory effect (p < 0.001) in the range of 84.14 to 92.54 %. The ACT produced significant (p < 0.001) inhibitory effect of 83.92 %. GC-MS analysis revealed the presence of 17 bioactive compounds, the most abundant of which were linoleic acid and palmitic acid.Conclusion: A. comosus displays strong antimalarial activity which supports the folkloric use of the plant for malarial treatment. A polyunsaturated fatty acid (linoleic acid) was the most abundant phytoconstituent identified. Keywords: Ananas comosus, Antimalarial, Malaria, Pineapple, Plasmodium beighe

Effects of methanol leaf extracts of Loranthus micranthus Linn from three host plants on some biochemical indices of diabetic rats

Purpose: To evaluate the effects of Loranthus micranthus leaf extracts from three host plants on the blood glucose, lipid profile and other biochemical indices of diabetic rats. Methods: The extracts of L. micranthus from Persea americana, Irvingia gabonensis and Cola acuminata were administered (orally at 200 mg/kg for 14 days) to alloxan-induced diabetic rats with glibenclamide serving as the standard drug. The fasting blood glucose (FBG), lipid profile, hematological indices and liver enzyme functions of the rats were determined. Phytochemical analysis of the extracts was carried out by standard methods. Results: The extracts reduced (p < 0.05) the FBG, low density lipoprotein (LDL), triglycerides and increased (p < 0.05) high density lipoprotein (HDL) and hematological parameters of the rats. However, there was no increase (p > 0.05) in liver enzymes. Phytochemical screening showed abundance of flavonoids, alkaloids, tannins and terpenoids. Conclusion: The study revealed that L. micranthus extracts from the three host plants possess antidiabetic, hypolipidemic and anti-anemic activities. Keywords: Anemia, Dyslipidemia, Enzymes, Hyperglycemia, Loranthus micranthus, Mistleto

Bioactivity guided fractionation of Icacina trichantha Oliv. (Icacinaceae) tuber for antimalarial activity against Plasmodium berghei infected mice and GC-MS profile of bioactive fraction

Aqueous methanol extract of the tuber of Icacina trichantha was prepared using cold maceration and dried in vacuo at 40°C. The extract was purified using solvent-solvent partitioning with n-hexane, dichloromethane, ethyl acetate, n-butanol. n-Hexane fraction was purified using Vacuum Liquid Chromatography, eluting with a gradient of dichloromethane in methanol (9:1, 7:3, 5:5, 0:10, each 500 mL) to obtain four sub-fractions. Acute toxicity study was done using Lorke’s method while in vivo anti-malarial study was carried out using suppressive model. Phytochemical analysis was carried out using standard procedure and most active sub-fraction was subjected to gas chromatography-mass spectroscopy. The extract at doses of 100, 200 and 400 mg/kg caused a significant (p<0.001) increase in percentage suppression of Plasmodium: 91.54 %, 94.48 % and 94.58% respectively. Phytochemical analysis of the extract revealed the presence of alkaloids, tannins, flavonoids saponin, glycoside, terpenoids, phenols, steroids, carbohydrates, reducing sugars. The GC-MS analysis showed the presence of eighteen compounds, the most abundant compound includes 9- octadecenoic acid (Z)-, methyl ester (oleic acid, 15.30%), 9, 12-octadecadienoic acid (Z, Z), methyl ester (linoleic acid, 14.34%). These findings suggest scientific evidence in support to the use of I. trichantha tuber for the management of malaria

RHAMNETIN IS A BETTER INHIBITOR OF SARS-COV-2 2’-O-METHYLTRANSFERASE THAN DOLUTEGRAVIR: A COMPUTATIONAL PREDICTION

Background: The 2’-O-methyltransferase is responsible for the capping of SARS-CoV-2 mRNA and consequently the evasion of the host’s immune system. This study aims at identifying prospective natural inhibitors of the active site of SARS-CoV-2 2’O-methyltransferase (2’-OMT) through an in silico approach. Materials and Method: The target was docked against a library of natural compounds obtained from edible African plants using PyRx - virtual screening software. The antiviral agent, Dolutegravir which has a binding affinity score of -8.5 kcal mol−1 with the SARS-CoV-2 2’-OMT was used as a standard. Compounds were screened for bioavailability through the SWISSADME web server using their molecular descriptors. Screenings for pharmacokinetic properties and bioactivity were performed with PKCSM and Molinspiration web servers respectively. The PLIP and Fpocket webservers were used for the binding site analyses. The Galaxy webserver was used for simulating the time-resolved motions of the apo and holo forms of the target while the MDWeb web server was used for the analyses of the trajectory data. Results: The Root-Mean-Square-Deviation (RMSD) induced by Rhamnetin is 1.656A0 as compared to Dolutegravir (1.579A0). The average B-factor induced by Rhamnetin is 113.75 while for Dolutegravir is 78.87; the Root-Mean-Square-Fluctuation (RMSF) for Rhamnetin is 0.75 and for Dolutegravir is 0.67. Also at the active site, Rhamnetin also has a binding affinity score of -9.5 kcal mol−1 and forms 7 hydrogen bonds as compared to Dolutegravir which has -8.5 kcal mol−1 and forms 4 hydrogen bonds respectively. Conclusion: Rhamnetin showed better inhibitory activity at the target’s active site than Dolutegravir

Alkaloids from Plants with Antimalarial Activity: A Review of Recent Studies

Malaria is one of the major health problems in developing countries. The disease kills a large number of people every year and also affects financial status of many countries. Resistance of the plasmodium parasite, the causative agent, to the existing drugs, including chloroquine, mefloquine, and artemisinin based combination therapy (ACT), is a serious global issue in malaria treatment and control. This warrants an urgent quest for novel compounds, particularly from natural sources such as medicinal plants. Alkaloids have over the years been recognized as important phytoconstituents with interesting biological properties. In fact, the first successful antimalarial drug was quinine, an alkaloid, which was extracted from Cinchona tree. In the present review work, the alkaloids isolated and reported recently (2013 till 2019) to possess antimalarial activity are presented. Several classes of alkaloids, including terpenoidal, indole, bisindole, quinolone, and isoquinoline alkaloids, were identified with a promising antimalarial activity. It is hoped that the reports of the review work will spur further research into the structural modification and/or development of the interesting compounds as novel antimalarial drugs

Thermodynamic and Spectrophotometric Studies of Electron Donor-Acceptor Complexation Between Loratadine and Chloranilic Acid

Purpose: To developing a simple, rapid and reliable analytical method for loratadine based on charge transfer complexation with chloranilic acid. Methods: The complex between loratadine and the complexing agent, chloranilic acid, was formed by mixing appropriate volumes of their solutions in non-aqueous media. Some features of the formed complex, such as molar ratio of the reaction and effect of time, were determined spectrophotometrically. Thermodynamic parameters were determined as well, the method was utilized in the assay of the drug in both bulk and tablet dosage forms. Results: The complex showed a wavelength of maximum absorption (λmax) at 527 nm (λmax of loratadine alone was 440 nm). Beer’s law was obeyed in the concentration range of 3.2 - 28.8 mg% (r2 = 0.9997). The stoichiometry of the complex was 2:1 (loratadine: chloranilic acid) and the complex was stable for over 60 min. Thermodynamic results show that as temperature changed from 30 to 70 °C, enthalpy change (∆H) was steady at -0.254 kcal.mol-1 while the free energy (∆G) changed from -3.904 to -4.450 kcal.mol-1. The complex appeared to be more stable at the slightly elevated temperature of 50 °C with a value of 757.14 mol-1. Analysis of the drug in both bulk and dosage forms showed good accuracy and precision with recovery ranging from 99.98 ± 1.00 to 100.94 ± 2.39 %. Conclusion: Charge transfer complexation method with chloranilic acid was successfully developed for the simple, rapid and accurate determination of loratadine

Spectrophotometric Determination and Thermodynamic Parameters of Charge Transfer Complexation Between Stavudine and Chloranilic Acid

Purpose: The official assay methods for most antiretroviral drugs are limited by cost and unavailability of good test equipment in several developing countries. Therefore, this study investigates the use of charge transfer complexation in the spectrophotometric assay of stavudine as an alternative method to conventional methods. Methods: Charge transfer complex formation between stavudine (n-donor) and chloranilic acid (π-acceptor) in 1,4-dioxan using a spectrophotometer was employed. Thermodynamic parameters of the complex formed were determined. The proposed method was employed in the analysis of commercially available stavudine dosage form. Results: The wavelength of maximum absorption (λmax) of the complex was at 526 nm compared to 457 nm for π-acceptor alone. Beer’s law was obeyed in the range of 5 - 40 mg % while the stoichiometry of the complex was found to be 2:1. The complex formed was still stable 24 h later. Its formation was spontaneous with a δHo of -3.78×103 J/mol. The standard entropy change was from 12.18 ± 0.78 to 11.08 ± 1.23 cal/deg/mol over the temperature range of 30 - 60 oC while molar absorptivity decreased from 2.45×105 to 1.2×105 over the same temperature range. The assay result of the standard stavudine solution was of high accuracy with a recovery value of 99.85 ± 1.95 %. Conclusion: The proposed method is reliable and reproducible and should be suitable for the quality control of stavudine in bulk and dosage forms

Additional file 1 of Prediction of HIV-1 protease cleavage site from octapeptide sequence information using selected classifiers and hybrid descriptors

Additional file 1: Fig. S1. Confusion matrix of our models using the testing set