Determination of Major Ion Concentration and Ionic Strength of Saline Water: A Case Study of Lakes; Nakuru, Bogoria-Kenya and Nata Saltpan Sanctuary –Botswana

Lakes Nakuru, Bogoria and Nata salt pan are of great ecological and economic importance. They are home to one of the world’s renowned bird sanctuaries with over 400 bird species, lesser flamingoes and breeding ground for a host of water birds including pelicans and flamingoes. These aquatic ecosystems are however; threatened by environmental pollution mainly due to anthropogenic activities in the catchment basins. The current study therefore, sought to determine the concentration of individual ions of saline waters and ionic strength in Lake Nakuru, Lake Bogoria (Kenya) and Nata Saltpan Sanctuary (Botswana) so as to form the baseline information for periodic monitoring and remediation of such aquatic saline systems amid the environmental pollution. Identification of individual dissolved ions can also be used as an indicator of the source of pollution. Samples were collected during the dry season by stratified sampling technique using Van Dorn Sampler. Water temperatures were generally high and consistent with the ambient air temperatures and pH values were 10.55±0.09, 10.15±0.18 and 9.97±0.33 for Nakuru, Bogoria and Nata saltpan respectively. Mean conductivity of values of 47.77±0.78, 62.50±0.37 and 12.79±0.33 were recorded for Lakes Nakuru, Bogoria and Nata saltpans respectively. Cation concentration were dominated by Na+ followed by K+, Ca2+ and Mg2+ and significant amount of trace anions in Lake Nakuru, Bogoria and Nata saltpan. Ionic strength for lakes Nakuru, Bogoria and Nata saltpan waters was 0.166, 0.195 and 0.059 M respectively. The findings of the study showed high level of ions in lakes Nakuru and Bogoria compared to Nata Saltpan. This was attributed to high agricultural and industrial activities in the catchment area. Key Words: Salinity, Conductivity, Ionic strength, Pollution, Water

Antimalarial activities and toxicity levels of selected medicinal plants used in Kenya

Background: Resistance development to antimalarial drugs necessitates the look at traditional medicinal plants as sources of novel compounds that could have the otential to be developed into new antimalarial therapies. Four medicinal plants used in Kenya to treat malaria were investigated. Objective: To determine the in vitro and in vivo antimalarial activity and safety of four medicinal plants used in Kenya to treat malaria. Materials and Methods: Ximenia americana, Sericocomopsis hilderbrandtii, Pentas lanceolata and Fuerstia africana were collected from their habitat, dried, and extracted with methanol and aqueous solvents. In vitro antiplasmodial activity carried out using Plasmodium falciparum, In vivo antimalarial activity using Plasmodium berghei ANKA strain in Swiss albino mice. Cytotoxicity was carried out using MTT assay on VeroE99 cell lines, acute toxicity was investigated in Swiss albino mice. Results: All extracts had good in vitro activity against D6 strain of Plasmodium falciparum with IC50<20µg/ml.  Aerial parts of Fuerstia africana methanol extract had the highest in vitro activity.  Seven extracts showed good in vivo activity with chemosuppresion >30% while three demonstrated low activity. Fuerstia africana was moderately cytotoxic. Except for Ximenia americana water extract, all the extracts were safe with LD50 > 5000mg/Kg. Conclusion: Results of this study support medicinal use of these plants and indicate that useful compounds can be isolated for further exploitation, formulation and use. Keywords: Medicinal plants, antiplasmodial activity, cytotoxicity, acute toxicit

HIV-1 Integrase Inhibitory Effects of Major Compounds Present in CareVid™: An Anti-HIV Multi-Herbal Remedy

In our continued study on the anti-HIV activity of compounds present in CareVidTM, we report the HIV-1 integrase ((HIV-1 IN) inhibitory effects of pellitorine (1), oleuropein (2), magnoflorine (3), crotepoxide (4), ent-kaurane-16β,17-diol (5), crotocorylifuran (6), lupeol (7), betulin (8), and ellagic acid (9) in an in vitro enzyme assay, and in an in silico study. Ellagic acid, pellitorine, lupeol, and betulin showed an in vitro percentage inhibition against HIV-1 IN of 21.1%, 19.0%, 18.5%, and 16.8%, respectively, at a standard concentration of 25 μg/mL. However, from a pharmacokinetic perspective, ellagic acid has poor bioavailability, due to rapid elimination in metabolism in the gut microbiome. It was postulated that known gut catabolites of ellagic acid, urolithin A (10) and urolithin B (11) could be more promising candidates in exploring the anti-HIV activity of ellagic acid-rich medicinal species consumed orally. On the contrary, urolithin A and urolithin B demonstrated lower activity with comparison to ellagic acid. The binding affinity of compounds 1–9, urolithin A, and urolithin B against the catalytic domain of HIV-1 IN was also explored by in silico methods. Docking studies showed oleuropein as the best candidate, with a predicted energy of binding of ΔG −5.81 kcal/mol, while ellagic acid showed moderate predicted inhibition (ΔG −4.38 kcal/mol) caused by the interaction between the carbonyl and the key Mg2+ ion in the active site

HIV-1 Reverse Transcriptase Inhibition by Major Compounds in a Kenyan Multi-Herbal Composition (CareVid™): In Vitro and In Silico Contrast.

CareVid is a multi-herbal product used in southwest Kenya as an immune booster and health tonic and has been anecdotally described as improving the condition of HIV-positive patients. The product is made up of roots, barks and whole plant of 14 African medicinal plants: Acacia nilotica (L.) Willd. ex Delile (currently, Vachelia nilotica (L.) P.J.H Hurter & Mabb.), Adenia gummifera (Harv.) Harms, Anthocleista grandiflora Gilg, Asparagus africanus Lam., Bersama abyssinica Fresen., Clematis hirsuta Guill. & Perr., Croton macrostachyus Hochst. ex Delile, Clutia robusta Pax (accepted as Clutia kilimandscharica Engl.), Dovyalis abyssinica (A. Rich.) Warb, Ekebergia capensis Sparm., Periploca linearifolia Quart.-Dill. & A. Rich., Plantago palmata Hook.f., Prunus africana Hook.f. Kalkman and Rhamnus prinoides L’Her. The objective of this study was to determine the major chemical constituents of CareVid solvent extracts and screen them for in vitro and in silico activity against the HIV-1 reverse transcriptase enzyme. To achieve this, CareVid was separately extracted using CH2Cl2, MeOH, 80% EtOH in H2O, cold H2O, hot H2O and acidified H2O (pH 1.5–3.5). The extracts were analysed using HPLC–MS equipped with UV diode array detection. HIV-1 reverse transcriptase inhibition was performed in vitro and compared to in silico HIV-1 reverse transcriptase inhibition, with the latter carried out using MOE software, placing the docking on the hydrophobic pocket in the subdomain of p66, the NNRTI pocket. The MeOH and 80% EtOH extracts showed strong in vitro HIV-1 reverse transcriptase inhibition, with an EC50 of 7 μg·mL−1. The major components were identified as sucrose, citric acid, ellagic acid, catechin 3-hexoside, epicatechin 3-hexoside, procyanidin B, hesperetin O-rutinoside, pellitorine, mangiferin, isomangiferin, 4-O-coumaroulquinic acid, ellagic acid, ellagic acid O-pentoside, crotepoxide, oleuropein, magnoflorine, tremulacin and an isomer of dammarane tetrol. Ellagic acid and procyanidin B inhibited the HIV-1 reverse transcription process at 15 and 3.2 µg/mL−1, respectively. Docking studies did not agree with in vitro results because the best scoring ligand was crotepoxide (ΔG = −8.55 kcal/mol), followed by magnoflorine (ΔG = −8.39 kcal/mol). This study showed that CareVid has contrasting in vitro and in silico activity against HIV-1 reverse transcriptase. However, the strongest in vitro inhibitors were ellagic acid and procyanidin B