Mosquito Larvicidal Constituents from Lantana Viburnoides SP Viburnoides Var Kisi (A. rich) Verdc (Verbenaceae).

\ud \ud Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae. Twenty late III or early IV instar larvae of An. gambiae s.s. were exposed to various concentrations of the plant extracts, fractions, blends and pure compounds, and were assayed in the laboratory by using the protocol of WHO 1996. Mean mortalities were compared using Dunnett's test (p < 0.05) and lethal concentration calculated by Lackfit Inversel of the SAS programme. The crude extract (LC50 = 7.70 ppm in 72 h) and fractions exhibited different level of mosquito larvicidal activity with subtraction of some fractions resulting in activity enhancement. The active fractions contained furanonaphthaquinones regio-isomers (LC50 = 5.48-5.70 ppm in 72 h) and the lantadene triterpenoid camaric acid (LC50 = 6.19 ppm in 72 h) as active principles while the lupane triterpenoid betulinic acid (LC50 < 10 ppm in 72 h) was obtained from the least active fraction. Crude extracts and some fractions had higher or comparable larvicidal activity to the pure compounds. These results demonstrate that L. viburnoides sp viburnoides var kisi extracts may serve as larvicides for managing various mosquito habitats even in their semi-purified form. The isolated compounds can be used as distinct markers in the active extracts or plant materials belonging to the genus Lantana

Antimosquito Phenylpropenoids from the Stem and Root Barks of Uvariodendron pycnophyllum (Diels) R.E.Fr

The phenylpropenoids O-methyleugenol, O-methylisoeugenol and 2,3-dimethoxycinnamaldehyde, have been isolated as the antimosquitocidal principles of the stem and root bark extracts of Uvariodendron pycnophyllum (Diels) R.E. Fr. The extracts and compounds exhibited activity with LC50 values in the range 17-59 ppm against the Anopheles gambiae s.s Giles mosquito larvae, while the constituent phenylpropenoids showed long term mortality effects to adult An. gambiae mosquito on impregnated bednets, and mosquito repellency that was stronger than the activity of the standard repellent DEET

In ovo antiviral potency of the leaf constituents of Tanzanian Toussaintia species against Infectious Bursal Disease Virus and Newcastle Disease Virus

The chemical constituents of Toussantia orientalis and T. patriciae (Annonaceae) leaf extracts were evaluated for their antiviral activities in ovo against Infectious Bursal Disease Virus (IBDV) and Newcastle Disease Virus (NDV). The nine-day-old embryonated eggs in a set of five were used for testing through the allantoic route inoculation assay for each tested compound and controls. For NDV assay, the allantoic fluids from the specimens were further harvested to determine viral contagion. The tested compounds exhibited potency with varying levels of significance at a screening concentration of 360 µg/ml against the two viral strains. Embryos infected with IBDV survived, grew to normal size with complete organ formation and had mean weights comparable to those of the uninfected ones when treated with the aminocinnamoyl tetraketides 1, 2, and 4, glucosylflavonoid 7 from T. orientalis and ursolic acid derivatives 9 and 10 from T. patriciae demonstrating high efficacy against IBDV. The compounds also exhibited antiviral activity against NDV, showing viral titre reduction ranging from 1:16 - 1:256 in the haemagglutination test, with compound 11 having the lowest titre value (1:16) followed by compound 7 (1:32). The compounds that exhibited significant antiviral efficacy could be considered potential leads for the development of antiviral agents.Keywords: Aminocinnamoyl tetraketides, ursolic acids, Toussaintia orientalis, Toussaintia patriciae, Annonaceae

Examination of the Legal Framework for Safeguarding Customary Land Rights in Tanzania.

Ensuring the safeguarding of customary land rights is of utmost importance in Tanzania and other developing nations. This is because most rural residents rely on customary norms to claim and occupy land, often lacking written documentation to validate their land ownership. A robust and comprehensive legal framework is indispensable to secure these rights effectively. Despite the Village Land Act's declaration in section 18(1) that customary and statutory rights hold equal status, customary land rights are frequently perceived as weaker and subordinate. With this perspective in mind, this study aims to examine the current legal framework governing the protection of customary land rights in Tanzania. This study utilizes a combination of doctrinal and comparative legal research methods. In the comparative legal research approach, we have considered best practices from South Sudan and Uganda. The findings of this study reveal that although Tanzania has made significant strides in protecting customary land rights through its existing laws, certain deficiencies persist, undermining the security of these rights. Consequently, this study recommends amendments to certain land laws that are incongruent with the protection of customary land rights, thereby enhancing the legal framework to better uphold the rights of those who rely on customary land tenure systems

New Glucopyranosylglyceryl-N-Octenyl Adipate and Bioactivity of Retro and Condensed Chalcones from Toussaintia Orientalis

1-(3-β-D-Glucopyranosylglycer-2-yl)-6-N-(oct-2-enyl)-adipate, [orientalin, 1] was isolated as a new metabolite from the polar leaf extracts of Toussaintia orientalis Verdc (Annonaceae), together with the glycoflavonoids afzelin and quercitrin, and the indolidinoids toussaintines A-C. The reversed chalcones 2-hydroxy-3,4,6-trimethoxychalcone (2) and 2-hydroxy-3,4,6- trimethoxydihydrochalcone (3), the condensed chalcone (+)-6a,12a-dihydro-6-phenyl-7-styryl- 6H,7H-[1]benzopyrano[4,3-][l]benzopyran (4), and mixtures of known triterpenoids and steroids were isolated from the less polar extracts of the root and stem bark of the same plant. The structures were established upon detailed analysis of spectroscopic data and other physical parameters. The chalcones exhibited antimicrobial, anti-inflammatory, antiproliferative and cytotoxic activity at varying efficacy levels, the reversed chalcone 2 demonstrating antiinflammatory potency against COX-2 enzyme that was superior to the standard drug Indomethacin. These results have further indicated the versatility of Annonaceae species in accumulating structurally varied natural products, some of them having unprecedented structures.Keywords: Toussaintia orientalis; Annonaceae; orientalin, 1-(3-b-D-glucopyranosylglycer-2-yl)-6-N-(oct-2-enyl)-adipate; condensed and retrochalcones; anti-inflammatory

Chemical constitutents and cytotoxicity of some Tanzanian wild mushrooms

The sterol ergosterol and ergosta-4,22-diene-3&#946,7&#945-diol, together with 4-hydroxybenzaldehyde were isolated from the mushroom species Polyporus molluscensis, Cantharellus isabelinus, C. symoensii and a Podaxis species. Their structures were established on the basis of spectroscopic data. The ethanol extracts of mushroom samples of Agaricus sp. and Termitomyces letestui also showed cytotoxicity against the brine shrimp larvae. Tanzania Journal of Science Vol. 31 (2) 2005: pp. 1-

Constituents of the Essential Oil of Suregada zanzibariensis Leaves are Repellent to the Mosquito, Anopheles gambiae s.s.

In traditional African communities, repellent volatiles from certain plants generated by direct burning or by thermal expulsion have played an important role in protecting households against vectors of malaria and other diseases. Previous research on volatile constituents of plants has shown that some are good sources of potent mosquito repellents. In this bioprospecting initiative, the essential oil of leaves of the tree, Suregada zanzibariensis Verdc. (Angiospermae: Euphobiaceae) was tested against the mosquito, Anopheles gambiae s.s. Giles (Diptera: Culicidae) and found to be repellent. Gas chromatography (GC), GC-linked mass spectrometry (GC-MS) and, where possible, GC-co-injections with authentic compounds, led to the identification of about 34 compounds in the essential oil. About 56% of the constituents were terpenoid ketones, mostly methyl ketones. Phenylacetaldehyde (14.4%), artemisia ketone (10.1%), (1S)-(-)-verbenone (12.1%) and geranyl acetone (9.4%) were the main constituents. Apart from phenylacetaldehyde, repellent activities of the other main constituents were higher than that of the essential oil. The blends of the main constituents in proportions found in the essential oil were more repellent to An. gambiae s.s. than was the parent oil (p < 0.05), and the presence of artemisia ketone in the blend caused a significant increase in the repellency of the resulting blend. These results suggested that blends of some terpenoid ketones can serve as effective An. gambiae s.s. mosquito repellents