Removing other Tree Species does not benefit the Timber Species Cephalosphaera Usambarensis

The endemic canopy tree Cephalosphaera usambarensis is a valuable timber species in montane rainforest of Tanzania. Here we evaluate an experiment in which mature trees of species other than C. usambarensis were removed from an area in the East Usambara Mountains. We compared stage/size structure of the trees in this  area   to structure in three nearby control areas from which potential competitors had not been removed. The removal area contained a slightly higher density of large C. usambarensis trees than did control areas, but these trees had not grown bigger than those in control areas in the quarter century since removal. Furthermore, the removal area contained far fewer newly-dispersed seeds, seedlings, or small sapling trees. Thus there is no evidence that removal of potential interspecific competitors enhances the population density or biomass (tree size x density of individuals) of the C. usambarensis population. Instead, removing other trees not only sacrifices local forest biodiversity, but also may harm future timber yield of C. usambarensis by suppressing recruitment of new individuals into the population

Antibacterial, Anti-HIV-1 Protease and Cytotoxic Activities of Aqueous Ethanolic Extracts from Combretum Adenogonium Steud. Ex A. Rich (Combretaceae).

\ud \ud Records have shown that Combretum adenogonium Steud. Ex A. Rich (Combretaceae) is used in traditional medicine systems of several tribes in Tanzania. This study focused on the investigation of antibacterial activity, anti-HIV-1 protease activity, toxicity properties and classes of phytochemicals in extracts from C. adenogonium Steud. Ex A. Rich (Combretaceae) to evaluate potential of these extracts for development as herbal remedies. Dried plant material were ground to fine powder and extracted using 80% aqueous ethanol to afford root, leaf and stem bark extracts. The extracts were assayed for anti-HIV-1 protease activities, antibacterial activities using microdilution methods and cytotoxicity using brine shrimps lethality assay. Screening for major phytochemical classes was carried out using standard chemical tests. All extracts exhibited antibacterial activity to at least one of the test bacteria with MIC-values ranging from 0.31-5.0 mg/ml. Two extracts, namely, root and stem bark exhibited anti-HIV-1 PR activity with IC50 values of 24.7 and 26.5 μg/ml, respectively. Stem bark and leaf extracts showed mild toxicity with LC50 values of 65.768 μg/ml and 76.965 μg/ml, respectively, whereas roots were relatively non-toxic (LC50 = 110.042 μg/ml). Phytochemical screening of the extracts indicated presence of flavonoids, terpenoids, alkaloids, tannins, glycosides and saponins. These results provide promising baseline information for the potential development of C. adenogonium extracts in treatment of bacterial and HIV/AIDS-related opportunistic infections

Antimicrobial activity and brine shrimp toxicity of extracts of Terminalia brownii roots and stem

BACKGROUND: Ternimalia brownii Fresen (Combretaceae) is widely used in traditional medicine to treat bacterial, fungal and viral infections. There is a need to evaluate extracts of this plant in order to provide scientific proof for it's wide application in traditional medicine system. METHODS: Extraction of stem bark, wood and whole roots of T. brownii using solvents of increasing polarity, namely, Pet ether, dichloromethane, dichloromethane: methanol (1:1), methanol and aqua, respectively, afforded dry extracts. The extracts were tested for antifungal and antibacterial activity and for brine shrimp toxicity test. RESULTS: Extracts of the stem bark, wood and whole roots of T. brownii exhibited antibacterial activity against standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, and Bacillus anthracis and the fungi, Candida albicans and Cryptococcus neoformans. Aqueous extracts exhibited the strongest activity against both bacteria and fungi. Extracts of the roots and stem bark exhibited relatively mild cytotoxic activity against brine shrimp larvae with LC(50 )values ranging from 113.75–4356.76 and 36.12–1458.81 μg/ml, respectively. The stem wood extracts exhibited the highest toxicity against the shrimps (LC(50 )values 2.58–14.88 μg/ml), while that of cyclophosphamide, a standard anticancer drug, was 16.33 (10.60–25.15) μg/ml. CONCLUSION: These test results support traditional medicinal use of, especially, aqueous extracts for the treatment of conditions such as diarrhea, and gonorrhea. The brine shrimp results depict the general trend among plants of the genus Terminalia, which are known to contain cytotoxic compounds such as hydrolysable tannins. These results warrant follow-up through bioassay-directed isolation of the active principles

Larvicidal, antimicrobial and brine shrimp activities of extracts from Cissampelos mucronata and Tephrosia villosa from coast region, Tanzania

<p>Abstract</p> <p>Background</p> <p>The leaves and roots of <it>Cissampelos mucronata </it>A. Rich (Menispermaceae) are widely used in the tropics and subtropics to manage various ailments such as gastro-intestinal complaints, menstrual problems, venereal diseases and malaria. In the Coast region, Tanzania, roots are used to treat wounds due to extraction of jigger. Leaves of <it>Tephrosia villosa </it>(L) Pers (Leguminosae) are reported to be used in the treatment of diabetes mellitus in India. In this study, extracts from the roots and aerial parts of <it>C. mucronata </it>and extracts from leaves, fruits, twigs and roots of <it>T. villosa </it>were evaluated for larvicidal activity, brine shrimps toxicity and antimicrobial activity.</p> <p>Methods</p> <p>Powdered materials from <it>C. mucronata </it>were extracted sequentially by dichloromethane followed by ethanol while materials from <it>T.villosa </it>were extracted by ethanol only. The extracts obtained were evaluated for larvicidal activity using <it>Culex quinquefasciatus </it>Say larvae, cytotoxicity using brine shrimp larvae and antimicrobial activity using bacteria and fungi.</p> <p>Results</p> <p>Extracts from aerial parts of <it>C. Mucronata </it>exhibited antibacterial activity against <it>Staphylococcus aureus</it>, <it>Escherichia coli</it>, <it>Pseudomonas aeruginosa</it>, <it>Salmonella typhi</it>, <it>Vibrio cholera</it>, <it>Bacillus anthracis</it>, <it>Streptococcus faecalis </it>and antifungal activity against <it>Candida albicans </it>and <it>Cryptococcus neoformans</it>. They exhibited very low toxicity to brine shrimps and had no larvicidal activity. The root extracts exhibited good larvicidal activity but weak antimicrobial activity. The root dichloromethane extracts from <it>C. mucronata </it>was found to be more toxic with an LC₅₀value of 59.608 μg/mL while ethanolic extracts from root were not toxic with LC₅₀>100 μg/mL). Ethanol extracts from fruits and roots of <it>T. villosa </it>were found to be very toxic with LC₅₀values of 9.690 μg/mL and 4.511 μg/mL, respectively, while, ethanol extracts from leaves and twigs of <it>T. villosa </it>were found to be non toxic (LC₅₀>100 μg/mL).</p> <p>Conclusion</p> <p>These results support the use of <it>C. mucronata </it>in traditional medicine for treatment of wounds. Extracts of <it>C. mucronata </it>have potential to yield active antimicrobial and larvicidal compounds. The high brine shrimp toxicity of <it>T. villosa </it>corroborates with literature reports that the plant is toxic to both livestock and fish. The results further suggest that <it>T. villosa </it>extracts have potential to yield larvicidal and possibly cytotoxic compounds. Further studies to investigate the bioactive compounds responsible for the observed biological effects are suggested.</p

Screening of Tanzanian medicinal plants for anti-Candida activity

BACKGROUND: Candida albicans has become resistant to the already limited, toxic and expensive anti-Candida agents available in the market. These factors necessitate the search for new anti-fungal agents. METHODS: Sixty-three plant extracts, from 56 Tanzanian plant species obtained through the literature and interviews with traditional healers, were evaluated for anti-Candida activity. Aqueous methanolic extracts were screened for anti-Candida activity by bioautography agar overlay method, using a standard strain of Candida albicans (ATCC 90028). RESULTS: Twenty- seven (48%) out of the 56 plants were found to be active. Extracts of the root barks of Albizia anthelmintica and Balanites aegyptiaca, and roots of Plectranthus barbatus showed strong activity. CONCLUSION: The extracts that showed strong anti-Candida activity are worth of further investigation in order to isolate and identify the active compounds