Isolation, characterization and antiplasmodial activity of phytochemical constituents from Monanthotaxis parvifolia (Oliv.) Verdc ssp. kenyensis Verdc

Fractionation of the methanol extract of the leaves of Monanthotaxis parvifolia (Oliv.) Verdc ssp. kenyensis Verdc (Annonaceae) by preparative high performance liquid chromatography yielded seven fractions from which two phytochemical constituents were isolated and identified as quercetin-3-O-β-galactopyranoside (hyperoside) and quercetin-3-O-α-arabinofuranoside (avicularin) on the basis of spectroscopic data analysis and comparison with published data for the known compounds. This is the first report of the isolation of these compounds from Monanthotaxis parvifolia. Hyperoside and avicularin exhibited moderate antiplasmodial activity against chloroquine sensitive (D10) and chloroquine resistant (Dd2) Plasmodium falciparum strains (IC50 = 10.85 - 38.07 μg/ml). Hyperoside had selectivity index greater than 10 when assayed for cytotoxicity on Chinese hamster ovarian cell line.Keywords:  Monanthotaxis parvifolia (Oliv.) Verdc ssp. kenyensis Verdc, quercetin glycosides, antiplasmodial activity, cytotoxicit

The Antimalarial and Antimicrobial Activity and Brine Shrimp Toxicity of Clematis Brachiata Extracts

The in vitro antimalarial activity of the root extract in partly supports the ethnobotanical use of the plant to manage malaria. Clematis brachiata Thunberg (Ranunculaceae) is used in Kenya for the management of headaches, malaria and other febrile illnesses, abdominal disorders, yaws and for skin disorders. Old stems and leaves are chewed for the management of toothaches and sore throats. Extracts of the plant were subjected to tests for antimalarial, antibacterial and antifungal activity. The toxicity of the extracts was assessed using the brine shrimp lethality bioassay. The root extract gave the highest in vitro antimalarial activity against the mulitidrug resistant strain, Plasmodium falciparum VI/S (IC50=39.24 mg/ml). The stem and leaf extracts had insignificant antiplasmodial activity. The leaf, stem and root extracts had no bacterial or fungal inhibitory effects even at very high concentrations of 10 mg/ml. The LD50 values of the stem and leaf methanol extracts against the brine shrimp larvae was 365.60 and 66.5 mg/ml, respectively. (E & C Afr Jnl Pharm Sci: 2002 5(1): 15-18

Trends of anticoagulation control among adult outpatients on long-term Warfarin therapy in a Tertiary Teaching and Referral Hospital in Kenya

Background: Anticoagulation control using warfarin therapy has several challenges especially in resource constrained settings.Objective: To describe the trends of anticoagulation control among adult outpatients on warfarin therapy at Kenyatta National Hospital. Design: Cross-sectional study.Setting: Anticoagulation clinics in the hospital. Participants: 180 outpatients aged ≥18 years.Main outcome measures: Level of anticoagulation and adverse drug reactions (ADRs). Methods: Participants’ sociodemographic characteristics and details of ADRs were acquired through face-to-face interviews. The level of anticoagulation was determined through assessment of international normalized ratios (INRs) for the six clinic attendances with INR of 2-3 being considered therapeutic. Data analysis was conducted onto IBM Statistical Package for Social Sciences version 23. Pearson’s Chi square was used to determine the strength of associations between outcome measures and  sociodemographics, with statistical significance set at p≤0.05. Results: Females were majority (76.7%) and the mean age of participants was 43.4 (±13.2) years. Therapeutic anticoagulation was maintained by 35.2-48.4% patients across six follow-ups and was better among the males (p=0.0398) especially those suffering from heart diseases. ADRs were experienced by almost 50% of the patients where bleeding (27.8%) mainly occurred at INR>3(80.0%). ADRs were significantly more common among the participants without spouses, who were primarily suffering from heart diseases (p=0.0081).Conclusions: Anticoagulation control is poor though patients with cardioembolic disorders have better INRs but more ADRs. Clinical and laboratory monitoring of warfarin therapy should be intensified among females. Future studies should correlate warfarin anticoagulation control with patient, clinician or hospital related factors

Evaluation of the potential of the marine sponges of the Zanzibar Island to yield antimalarial and antimicrobial active compounds

Emergence of new and re-emergence of old infections continue to elude prospects of reducing morbidity and mortality caused by microbial infections. Trends of resistance to currently in use antimicrobials and antimalarials threaten to increase mortality caused by these infections. This study explores the potential of marine invertebrates as a source for new antimicrobials and antimalarials. The lactate dehydrogenase method was used to assay marine sponges for activity against Plasmodium falciparum, while the disc diffusion method was used to assay the extracts for antibacterial and antifungal activity. Extracts of some marine sponges from the Zanzibar Island exhibited both antiplasmodial and antimicrobial activities. Among the 55 marine sponge extracts that were tested 23 (41.8%) inhibited Plasmodium falciparum W2 strain by more than 50% at both 250 and 50 μg/ml concentrations. Moderate polar extracts were more active against Plasmodium falciparum W2 strain than polar and non-polar extracts. None of the 12 extracts that were tested on Plasmodium falciparum strain D6 exhibited inhibitory activity reaching 50%. Among 18 marine sponge extracts that were tested for antimicrobial activity 12 (66.7%) showed activity against one or more of the bacteria and fungi used ranging from weak to strong on an arbitrary criterion. The ethyl acetate extracts of Agelas mauritania and Oceanopia sp. exhibited high activity against the fungi Candida albicans and Cryptococcus neoformans . The best antibacterial profile was exhibited by ethyl acetate extracts of Aplysinopsis sp., Halichondrida sp. 1 and Oceanopia sp. In conclusion, these results support the need for intensified efforts to search for active antimalarial and antimicrobial compounds from the Zanzibar marine sponges