Faith A. Okalebo

In Vitro Antiplasmodial Activities and Synergistic Combinations of Differential Solvent Extracts of the Polyherbal Product, Nefang

Nefang, a polyherbal product composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, and Ocimum gratissimum (leaves), is a potential therapy against P. falciparum malaria. In vitro antiplasmodial activities of its constituent solvent extracts were analyzed on CQ-sensitive (3D7) and multidrug resistant (Dd2) P. falciparum strains. The interactions involving the differential solvent extracts were further analyzed using a variable potency ratio drug combination approach. Effective concentration 50 (EC50) values were determined by nonlinear regression curve-fitting of the dose-response data and used in calculating the fractional inhibitory concentration 50 (FIC50) and combination indices (CI) for each pair. The derived EC50 values (3D7/Dd2, μg/mL) are Nefang-96.96/55.08, MiB-65.33/34.58, MiL-82.56/40.04, Pg-47.02/25.79, Cp-1188/317.5, Cc-723.3/141, Cs-184.4/105.1, and Og-778.5/118.9. Synergism was obtained with MiB/Pg (CI = 0.351), MiL/Pg (0.358), MiB/Cs (0.366), MiL/Cs (0.482), Pg/Cs (0.483), and Cs/Og (0.414) when analyzed at equipotency ratios. Cytotoxicity testing of Nefang and the solvent extracts on two human cell lines (Hep G2 and U2OS) revealed no significant toxicity relative to their antiplasmodial activities (SI > 20). Taken together, our data confirm the antimalarial activities of Nefang and its constituent plant extracts and identified extract pairs with promising synergistic interactions for exploitation towards a rational phytotherapeutic and evidence-based antimalarial drug discovery.

Anti-malarial activity of a polyherbal product (Nefang) during early and established Plasmodium infection in rodent models

BackgroundThe emerging resistance of Plasmodium species to currently available anti-malarials remains a public health concern, hence the need for new effective, safe and affordable drugs. Natural products remain a reliable source of drugs. Nefang is a polyherbal anti-malarial of the Cameroonian folklore medicine with demonstrated in vitro antiplasmodial and antioxidant activities. It is composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, Ocimum gratissimum (leaves). This study aimed at investigating the suppressive, prophylactic and curative activities of Nefang in Plasmodium infected rodent models.MethodsSystemic acute oral toxicity of Nefang aqueous and ethanol extracts was assessed in mice up to a dose of 5,000 mgkg−1 body weight. BALB/c mice and Wistar rats were inoculated with Plasmodium chabaudi chabaudi and Plasmodium berghei, respectively, and treated with Nefang, the Mangifera indica bark/Psidium guajava combination and a Psidium guajava leaf aqueous extracts (75, 150, 300 and 600 mgkg−1 bwt). Their schizonticidal activity was then evaluated using the Peter’s 4-day suppressive test). The prophylactic and curative (Rane’s Test) activity of Nefang was also evaluated by determining the parasitaemia, survival time, body weight and temperature in pre-treated rodents.ResultsAcute oral toxicity of the extract did not cause any observed adverse effects. Percent suppressions of parasitaemia at 600 mgkg−1 bwt were as follows (P. berghei/P. chabaudi): Nefang – 82.9/86.3, Mangifera indica bark/Psidium guajava leaf combination extract – 79.5/81.2 and Psidium guajava leaf – 58.9/67.4. Nefang exhibited a prophylactic activity of 79.5% and its chemotherapeutic effects ranged from 61.2 – 86.1% with maximum effect observed at the highest experimental dose.ConclusionThese results indicate that Nefang has excellent in vivo anti-malarial activities against P. berghei and P. chabaudi, upholding earlier in vitro antiplasmodial activities against multi-drug resistant P. falciparum parasites as well as its traditional use. Hence, Nefang represents a promising source of new anti-malarial agents.

Medicinal plants used for management of malaria among the Luhya community of Kakamega east sub-county, Kenya

Background Malaria remains a major health problem worldwide especially in sub-Saharan Africa. In Kenya, 80% of the population is at risk of contracting the disease. Pregnant mothers and children under five years are the most affected by this disease. Antimalarial drug resistance poses a major threat in the fight against malaria necessitating continuous search for new antimalarial drugs. Due to inadequate and inaccessible health facilities, majority of people living in rural communities heavily depend on traditional medicine which involves the use of medicinal plants for the management of malaria. Most of these indigenous knowledge is undocumented and risks being lost yet such information could be useful in the search of new antimalarial agents. Aim of study An ethnobotanical survey was carried out among the Luhya community of Kakamega East sub-County, a malaria epidemic region, with the aim of documenting the plants used in the management of malaria. Materials and methods Semi-structured questionnaires were used to collect information from 21 informants who included traditional medicine practitioners and other caregivers who had experience in use of plants in management of malaria. These were drawn from 4 villages located in Kakamega East sub-county, within Kakamega County based on their differences in topography. Information recorded included plant names, parts used, mode of preparation and administration and the sources of plant materials. A literature search was conducted using PubMed and google scholar to identify the reported traditional uses of these plants and studied antiplasmodial activities. Results In this study, 57% of the informants were aged above 50 years and a total of 61% had either no formal education or had only attained primary school education. A total of 42 plant species belonging to 24 families were identified. Most plants used in the management of malaria in this community belonged to Lamiaceae (18%), Leguminosae (9%) and Compositae (9%) plant families. Plants mostly used included Melia azedarach L, Aloe spp, Ajuga integrifolia Buch. Ham, Vernonia amygdalina Del., Rotheca myricoides (Hochst.) Steane and Mabb, Fuerstia africana T.C.E.Fr., Zanthoxylum gilletii (De Wild.) P.G.Waterman and Leucas calostachys Oliv. Rumex steudelii Hochst.ex A. Rich and Phyllanthus sepialis Müll. Arg are reported for the first time in the management of malaria. Although Clerodendrum johnstonii Oliv. (Jeruto et al., 2011) and Physalis peruviana L.(Ramadan et al., 2015) are reported in other studies for management of malaria, no studies have been carried out to demonstrate their antiplasmodial activity. The plant parts mostly used were the leaves (36%) and stem barks (26%). Majority of these plants were prepared as decoctions by boiling and allowed to cool before administration (66%) while infusions accounted for 28% of the preparations. The literature mined supports the use of these plants for the management of malaria since most of them have demonstrated in-vitro and in-vivo antiplasmodial activities. Conclusion Most of the reported plant species in this study have been investigated for antiplasmodial activity and are in agreement with the ethnomedical use. Two (2) plants are reported for the first time in the management of malaria. There is need for documentation and preservation of the rich ethnomedical knowledge within this community given that most of the practitioners are advanced in age and less educated. There is also the danger of over-exploitation of plant species as most of them are obtained from the wild, mainly Kakamega forest. Therefore, there is need for determining the economically and medicinally important plants in this community and planning for their preservation.

Pharmacological evidence for the folk use of Nefang: antipyretic, anti-inflammatory and antinociceptive activities of its constituent plants.

BackgroundNefang is a polyherbal anti-malarial composed of Mangifera indica (MiB and MiL; bark and leaf), Psidium guajava (Pg), Carica papaya (Cp), Cymbopogon citratus (Cc), Citrus sinensis (Cs) and Ocimum gratissimum (Og) (leaves). Previous studies have demonstrated its in vitro and in vivo antiplasmodial activities, antioxidant properties and safety profile. This study aimed at evaluating the antipyretic, anti-inflammatory and antinociceptive activities of the constituent plants of Nefang which are relevant to the symptomatic treatment of malaria fever.MethodsAntipyretic activities were determined by the D-Amphetamine induced pyrexia and Brewer’s Yeast induced hyperpyrexia methods. Anti-inflammatory activities were investigated using the carrageenan-induced rat paw edema method. Antinociceptive activities were determined by mechanical nociception in the tail pressure and thermal nociception in the radiant heat tail flick and hot plate methods. Data was analysed using the one way ANOVA followed by Neuman-Keuls multiple comparison test.ResultsBest percentage inhibition of induced pyrexia (amphetamine/brewer’s yeast; p < 0.05) was exhibited by Cc (95/97) followed by Og (85/94), MiL (90/89), MiB (88/84) and Cs (82/89). Cc and Og exhibited comparable activities to paracetamol (100/95).Anti-inflammatory studies revealed paw edema inhibition (%) as follows (p < 0.05): Indomethacin (47), MiL (40), Cp (30), MiB (28) and Og (22), suggesting best activity by MiL.Antinociceptive studies revealed significant (p < 0.01) pain inhibition (%) as follows: Paracetamol (97), Og (113), MiL (108), Pg (84) and MiB (88). Og and MiL exhibited the best activities.ConclusionThe results obtained suggest that the constituent plants possess biologically active compounds with antipyretic, anti-inflammatory and antinociceptive activities. These activities are essential in the symptomatic treatment of malaria fever, thereby justifying the folk use of Nefang. This would be useful in its subsequent development for clinical application.

Antioxidant potential of a polyherbal antimalarial as an indicator of its therapeutic value.

Nefang is a polyherbal product composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, and Ocimum gratissimum (leaves), used for the treatment of malaria. Compounds with antioxidant activity are believed to modulate plasmodial infection. Antioxidant activity of the constituent aqueous plants extracts, in vitro, was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), total phenolic content (TPC), and ferric reducing antioxidant power (FRAP) methods and, in vivo, Nefang (100 and 500 mg kg−1) activity was evaluated in carbon tetrachloride-induced oxidative stressed Wistar rats. Superoxide dismutase, catalase activities, and lipid peroxidation by the malondialdehyde and total proteins assays were carried out. P. guajava, M. indica leaf, and bark extracts had the highest antioxidant properties in all three assays, with no statistically significant difference. Rats treated with the carbon tetrachloride had a statistically significant decrease in levels of triglycerides, superoxide dismutase, and catalase (P < 0.05) and increase in malondialdehyde activity, total protein levels, and liver and renal function markers, whereas rats treated with Nefang showed increased levels in the former and dose-dependent decrease towards normal levels in the later. These results reveal the constituent plants of Nefang that contribute to its in vivo antioxidant potential. This activity is a good indication of the therapeutic potential of Nefang.

Management of Type 2 Diabetes Mellitus by Traditional Medicine Practitioners in Kenya- Key Informant Interviews

Introduction Worldwide, plant based medicines are increasing in popularity due to perceptions of safety and efficacy. Herbalists in Kenya are widely consulted for the management of many diseases including Type 2 Diabetes Mellitus (T2DM). This study investigated the level of knowledge of the herbalists in management of T2DM. Methods Purposive sampling was used to identify 4 herbalists working in the urban areas who actively manage T2DM. Key informant interviews were used to gather data about the management of T2DM. It was analyzed using a content thematic approach. Results Diverse management methods which included both pharmacological and non- pharmacological were noted. Glycemic control was assessed with the help of a glucometer. In addition, presenting signs and symptoms were key in diagnosing T2DM. The herbalists used various herbs, minerals and animals as medicinal sources. The drugs were dispensed as decoctions with excipients being added appropriately. Adverse effects were recorded. The herbalists acknowledged that patients use both herbal and allopathic medicine together. A level of record keeping was observed but patient follow-up was poor. The cost of the herbal drugs was perceived to be excessive. Conclusion Some similarities exist in the management of T2DM between allopathic and traditional medicine practitioners. Training of herbalists is required to improve the quality of care given to patients.

Impact of First Line Antiretroviral Therapy on Clinical Outcomes Among HIV-1 Infected Adults Attending One of the Largest HIV Care and Treatment Program in Nairobi Kenya

Objective: This study evaluated the immunologic (CD4 cell count), virological (HIV RNA viral load), hepatic (alanine and aspartate aminotransferase - ALT and AST), renal (creatinine) and hematological (hemoglobin -HB, White Blood Cell - WBC, Lymphocytes - LYM and platelets - PLT) response to a six months ART treatment among HIV participants in Nairobi Kenya. Methods: Blood samples were obtained from 599 consenting HIV infected participants receiving HIV treatment in Nairobi. CD4 cell counts were measured using flow cytometer and viral load determined using real-time polymerase chain reaction. The blood hematology, liver and kidney function tests were also measured. One-way ANOVA and Linear regression analysis were conducted. Results: The median age at ART initiation was 41 years (IQR 35-47 years). The majority of participants (60.3%) were female and 56.1% started on regimens with 2 NRTIs and efavirenz based NNRTI. About 40% of the participants were failing treatment 6 month post ART initiation. The CD4 count significantly increased at the 6-month post ART initiation (301.7 ± 199.4 to 329.4 ± 305.8; P 5 times the upper limit of normal - ULN) and renal abnormalities (elevated serum creatinine levels) were all high at month 6 compared to baseline; ALT (2.5 to 10.5%), AST (5.3 to 23.4%) and creatinine (63.4 to 68.84%). Fewer participants at month 6 had anemia (29.4% verses 56.4%), leucopenia (42.4% vs. 46.9%) and thrombocytopenia (6.5% vs. 84.1%) compared to baseline. In multivariable models, baseline levels of this parameter, ART regimen and duration with HIV at ART initiation were the most important determinant of month 6 levels. Conclusion: These data demonstrate sustained immunologic/virologic response to ART among participants remaining on therapy. Anemia, leucopenia and thrombocytopenia were minimized with marginal hepatotoxicity and renal impairment seen. Interventions leading to earlier HIV diagnosis and initiation of ART could substantially improve patient outcomes in Kenya.

Antiplasmodial prenylated flavanonols from Tephrosia subtriflora

Abstract The CH2Cl2/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC50 values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC50 > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC50 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC50 16.9 μM).

Point prevalence survey of antibiotic use and resistance at a referral hospital in Kenya: findings and implications

ABSTRACT Background and aims: A substantial amount of antibiotic use in hospitals may be inappropriate, potentially leading to the development and spread of antibiotic resistance, adverse effects, mortality and increased hospital costs. The objective was to assess current patterns of antibiotic use in a leading referral hospital in Western Kenya. This would lead to the identification of opportunities for quality improvement in this hospital and others across Kenya. Methodology: A point prevalence survey was carried out with data abstracted principally from patient medical records supplemented by interviews from physicians when needed. The pattern of antibiotic use was analyzed by descriptive methods. Differences in antibiotic use and indications between the selected wards were compared using the Chi-square test or Fisher’s exact tests. Results: Among the patients surveyed, 67.7% were on antibiotics. The most common classes of antibiotics prescribed were third generation cephalosporins (55%), imidazole derivatives like metronidazole (41.8%) and broad spectrum penicillins (41.8%). The most common indication for antibiotic use was medical prophylaxis (29%), with local guidelines advocating antibiotic prophylaxis in mothers after delivery of their child as well as in neonates with birth asphyxia and low weight at birth. Dosing of antibiotics was seen as generally optimal when assessed against current recommendations. Conclusion: Whilst the dosing of antibiotics seemed adequate, there was high use of antibiotics in this hospital. This needs to be urgently reviewed with currently appreciable empiric antibiotic use. Programmes are being instigated to address these concerns. This includes developing antibiotic guidelines and formularies especially for empiric use as well as implementing antimicrobial stewardship activities.

Comparison of zidovudine and tenofovir based regimens with regard to health-related quality of life and prevalence of symptoms in HIV patients in a Kenyan referral hospital

Aim: Zidovudine and tenofovir form the backbone of antiretroviral therapy in Kenya. However, their side-effects may affect the quality of life (QoL) of patients. The aim was to compare the health-related quality of life (HRQoL) of adult patients on tenofovir versus zidovudine based regimens in a referral hospital in Kenya to provide future guidance. Methods: A comparative cross sectional study among 501 adult out-patients on either tenofovir or zidovudine was undertaken in Kenyatta National Hospital between 2015 and 2016. The Medical Outcome Study HIV Health Survey (MOS-HIV) was administered along with other key aspects of treatment. Linear regression analysis was performed to identify determinants of HRQoL. Results: Patients on zidovudine had a higher Physical Health Summary Score (PHSS) and Mental Health Summary Score (MHSS) compared to those on tenofovir. The presence of any symptom of the disease and a stated inability to cope were negatively associated with PHSS, whilst having a regular source of income improved PHSS. Being on tenofovir, symptom of illness [β = -1.24; 95% CI (-2.253, -0.226)], absence of pain [β=0.413; 95% CI (0.152, 0.674)] and patient stated inability to cope with HIV [β = -1.029; 95% CI (-1.441, -0.617)] affected the MHSS. Patients on tenofovir and second line regimens had more signs and symptoms of illness. Conclusion: Participants on zidovudine based regimens showed a better performance across all aspects of HRQoL. These are considerations for the future.