S.C. Chhabra

Antiplasmodial activity of four Kenyan medicinal plants

A preliminary antiplasmodial and phytochemical screening of four Kenyan medicinal plants was carried out. The medicinal plants were extracted and tested for in vitro antiplasmodial activity against chloroquine-sensitive (K67) and chloroquine-resistant (ENT36) strains of Plasmodium falciparum. Out of 16 extracts, 12 were active against ENT36 strain while seven were active against K67 strain, that is, IC50 < or = 50 micrograms/ml. The most active extracts on both strains were those of leaves of Phyllanthus reticulatus Poir, and Suregada zanzibariensis Baill. (Euphorbiaceae) with IC50 < or = 10 micrograms/ml. The stembark of Terminalia spinosa Engl. (Combretaceae) and the stems of Dissotis brazzae Cogn. (Melastomataceae) had IC50 < or = 10 micrograms/ml for strains K67 and ENT36, respectively. A preliminary phytochemical analysis of these plants revealed the presence of different classes of primary and secondary metabolites.

Phytochemical Screening of Tanzanian Medicinal Plants. I.

To evaluate traditional medicine, which is an important part of the health-care system in Tanzania, three different regions, Coast, Morogoro and Kilimanjaro were surveyed for the herbs used by traditional healers. For each species, the botanical name, vernacular name, collection number and medical uses are given. Phytochemical screening of the 52 plant samples collected representing 49 species, 42 genera and 28 families was carried out. The analyses indicated that 94% plant samples contained steroids/triterpenoids, 50% saponins, 40% carotenoids and 17% alkaloids.

In vitro antiplasmodial activity of some plants used in Kisii, Kenya against malaria and their chloroquine potentiation effects.

Fifty-five organic and aqueous extracts of 11 plants used in malaria therapy in Kisii District, Kenya were tested in vitro against chloroquine (CQ)-sensitive and resistant strains of Plasmodium falciparum. Of the plants tested, 73% were active (IC(50) < 100 microg/ml). Three plants, Vernonia lasiopus, Rhamnus prinoides and Ficus sur afforded extracts with IC(50) values ranging less than 30 microg/ml against both CQ-sensitive and resistant strains. Combination of some extracts with CQ against the multi-drug resistant P. falciparum isolate V1/S revealed some synergistic effect. The plant extracts with low IC(50) values may be used as sources for novel antimalarial compounds to be used alone or in combination with CQ.

Cleome monophylla essential oil and its constituents as tick (Rhipicephalus appendiculatus) and maize weevil (Sitophilus zeamais) repellents

The repellency of the essential oil of the shrub Cleome monophylla (Family: Capparidaceae) and identified constituents of the oil were evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil of C. monophylla exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N, N‐diethyl toluamide (DEET). In a Y‐tube olfactometer bioassay, C. monophylla oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. 14 Compounds were identified in the C. monophylla oil by GC, GC‐MS and coinjection with authentic samples. Terpenolene was found to occur in largest quantity (14%) followed by 1‐α‐terpeneol (10%), pentacosane (9%), (α + β)‐humulene (8%), phytol (5%) and 2‐dodecanone (4%). The most repellent components against R. appendiculatus and S. zeamais were 1‐α‐terpeneol and 2‐dodecanone. The overall pattern of repellency activity of the C. monophylla constituents with respect to the two arthropods was, however, different. The potential of C. monophylla in tick and maize weevil control is discussed.

Plants used in traditional medicine in eastern tanzania. V. Angiosperms (passifloraceae to sapindaceae)

Sixty-one Angiosperms (Passifloraceae to Sapindaceae) are listed, which are used by traditional healers in five regions of Eastern Tanzania, namely, Coast, Dar es Salaam, Kilimanjaro, Morogoro and Tanga. For each species listed, the botanical name, vernacular name, collection number, locality, habit, distribution and medicinal uses are given. Additionally, information from the literature on medicinal uses, chemical constituents and pharmacological effects are also provided.

Plants used in traditional medicine in Eastern Tanzania. VI. Angiosperms (Sapotaceae to Zingiberaceae)

Fifty-three Angiosperm species (Sapotaceae to Zingiberaceae), which are used by traditional healers in five regions of Eastern Tanzania (Coast, Dar es Salaam, Kilimanjaro, Morogoro and Tanga) are listed. For each species, the botanical name, vernacular name, collection number, locality, habit, geographic distribution and medicinal uses are given. Additionally, information from the literature on medicinal uses, chemical constituents and pharmacological effects are also provided. Data analysis and conclusions to cover all the six parts of the papers previously published are presented.

Plants used in traditional medicine in eastern Tanzania. I. Pteridophytes and angiosperms (acanthaceae to canellaceae)

Seventy-seven plants are listed, which are used by traditional healers in five regions of eastern Tanzania, Coast, Dar es Salaam, Kilimanjaro, Morogoro and Tanga. For each species are given the botanical name, vernacular name, collection number, locality, habit, distribution and medical uses. Results of a literature survey are also reported, including medical use, isolated constituents and pharmacological effects.

Bioactive steroidal alkaloid glycosides from Solanum aculeastrum

Solanum aculeastrum Dunal was investigated for the presence of molluscicidal compounds. This led to the isolation of solaculine A, from the root bark in addition to known steroidal alkaloids; solamargine and beta-solamarine from the berries. The structures were elucidated by spectroscopic techniques. Molluscicidal activity of the aqueous extracts of the berries and root bark, and the isolated compounds were investigated.

Plants used in traditional medicine in eastern Tanzania. II. Angiosperms (Capparidaceae to Ebenaceae).

Sixty-nine plants are listed, which are used by traditional healers in five regions of Eastern Tanzania, Coast, Dar es Salaam, Kilimanjaro, Morogoro and Tanga. For each species the botanical name, vernacular name, collection number, locality, habit, distribution and medicinal uses are given. Results of a literature survey on medicinal uses, isolated constituents, and pharmacological effects are also provided.

Flavonoids from Tephrosia aequilata.

From the roots of the plant Tephrosia aequilata Baker, five flavonoids were isolated of which, 3,4:8,9-dimethylenedioxypterocarpan is reported for the first time. Its structure and those of the already known flavonoids were established by physical and spectroscopic analysis. Application of 2D NMR techniques was useful for complete characterization of the new pterocarpan as well as the other known flavonoids.