Larvicidal activities of five Kotschya species against Culex quinquefasciatus Say (Culicidae: Diptera)

Resistance of mosquito vectors to the commonly used chemical insecticides is posing threats to human health. It is becoming necessary to identify safe, eco-friendly and effective alternative sources of larvicides in order to reduce mosquito menace. HPLC profiling of the chemical constituents in the stem and root bark ethanol extracts had similar pattern of chemical constituents except for K. aeschynomenoides which indicated to have large quantity of polar compounds compared to others. In this study, the ethanolic extracts and powders of five Kotschya species were tested against Culex quinquefasciatus Say. Chemical profiling of the stem and root bark ethanol extracts from K. speciosa, K. thymodora, K. platyphylla, K. aeschynomenoides and K. strigosa did not show any major differences in terms of their chemical composition. At 0.5 mg/ml, the root and stem ethanol extracts from K. speciosa, K. thymodora and K. strigosa exhibited high larvicidal activity (≥ 70%) on the 8th day post treatment. Stem powder of K. thymodora and root powder of K. speciosa and K. strigosa had activity comparable to their respective extracts at 0.2% w/v and 0.4% w/v at the same exposure time. This suggests that Kotschya species contain same or related compounds in varying quantities that are responsible for larvicidal activity.Keywords: Fabaceae, Kotschya strigosa, K. speciosa, K. thymodora, K. platyphylla, K. aeschynomenoides, Larvicidal, Culex quinquefasciatu

Brine shrimp lethality of a glutarimide alkaloid from Croton sylvaticus Hochst

No Abstract.The East and Central African Journal of Pharmaceutical Sciences Vol. 8(1) 2005: 3-

Antimicrobial and cytotoxic activities of fresh leaf extracts of Warburgia ugandensis

Abstract: Warburgia ugandensis Sprague (Canellaceae), is widely used by Traditional Health Practitioners in Eastern and Southern Africa for treatment of diseases and conditions associated with HIV/AIDS infections. The most commonly prescribed parts of the plant are usually barks and roots. The aim of this study was to investigate whether leaves of this plant have biological activities comparable to those of barks and roots. Fresh leaves of W. ugandensis were freeze-dried to complete dryness while another portion of the leaves from the same collection were air-dried under shade. Ethanolic extracts from the two differently dried leaves weretested for antimicrobial activity and for brine shrimp toxicity test. Ethanolic extract from the freeze-dried leaves exhibited both antibacterial activity against standard strains of Staphylococcus aureus, Escherichia coli,Vibrio cholerae, Bacillus cereus and antifungal activity against Candida albicans and Cryptococcus neoformans. The extract from the air-dried leaves showed similar antibacterial activity against the mentioned organisms but hadno antifungal activity. However, both extracts exhibited comparable cytotoxic activity (95% CI), against brine shrimp larvae with reference to cyclophosphamide, a standard anticancer drug. Fresh leaves of W. ugandensis have shown to exhibit anticandida activity, a factor which substantiates their application as a traditional herbal remedy to complement treatment of fungal infections in HIV/AIDS patients. Further studies to establish constituents responsible for the exhibited antifungal activity are highly desirable

Anticonvulsant Activity Of Diospyros fischeri Root Extracts

Diospyros fischeri Gurke (Ebenaceae) is used in traditional medicine for the treatment of epilepsy. Dichloromethane, ethylacetate, and ethanol extracts of the roots, at doses between 100 and 1600 mg/kg BW,  inhibited convulsions induced by the γ‐aminobutyric acid type A (GABAA) receptor antagonist, pentylenetetrazole (PTZ), in a dose dependent manner. The extracts also exhibited low toxicity against brine shrimps giving LC50 values between 45 .4 and 95.4 μg/ml.  These results provide evidence for the potential of D. fischeri extracts to treat absence seizures, especially given their seemingly innocuous nature. Keywords: Diospyros fischeri; Pentylenetetrazole; Anticonvulsant activity; Brine shrimp toxicity African Journal of Traditional, Complementary and Alternative Medicines Vol. 4 (2) 2007: pp. 226-23

Brine Shrimp Toxicity Evaluation Of Some Tanzanian Plants Used Traditionally For The Treatment Of Fungal Infections

Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminary data of their toxicity using the brine shrimps test. The results indicate that 9 out of 44 plant species whose extracts were tested exhibited high toxicity with LC50 values below 20μg/ml. These include Aloe lateritia Engl. (Aloaceae) [19.1μg/ml], Cassia abbreviata Oliv. (Caesalpiniaceae) [12.7μg/ml], Croton scheffleri Pax (Euphorbiaceae) [13.7μg/ml], Hymenodactyon parvifolium Brig (Rubiaceae) [13.4μg/ml], Kigelia Africana L. (Bignoniaceae) [7.2μg/ml], and Ocimum suave Oliv. (Labiatae) [16.7μg/ml]. Twelve plants gave LC50 values between 21 and 50μg/ml, 11 plants gave LC50 values between 50 and 100 μg/ml, and 18 plants gave LC50 values greater than 100 μg/ml. Keywords: Brine shrimp test; Toxicity evaluation; Traditional antifungal plants African Journal of Traditional, Complementary and Alternative Medicines Vol. 4 (2) 2007: pp. 219-22

Herbal therapy associated with antibiotic therapy: potentiation of the antibiotic activity against methicillin – resistant Staphylococcus aureus by Turnera ulmifolia L

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus </it>genus is widely spread in nature being part of the indigenous microbiota of skin and mucosa of animal and birds. Some <it>Staphylococcus </it>species are frequently recognized as etiological agents of many animal and human opportunistic infections This is the first report testing the antibiotic resistance-modifying activity of <it>Turnera ulmifolia </it>against methicillin-resistant <it>Staphylococcus aureus </it>– MRSA strain.</p> <p>Methods</p> <p>In this study an ethanol extract of <it>Turnera ulmifolia </it>L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with aminoglycosides against an MRSA strain.</p> <p>Results</p> <p>The synergism of the ethanol extract and aminoglycosides were verified using microdillution method. A synergistic effect of this extract on gentamicin and kanamycin was demonstrated. Similarly, a potentiating effect of chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides.</p> <p>Conclusion</p> <p>It is therefore suggested that extracts from <it>Turnera ulmifolia </it>could be used as a source of plant-derived natural products with resistance-modifying activity, constituting a new weapon against the problem of bacterial resistance to antibiotics demonstrated in MRSA strains.</p