Lesser Known Aromatic Plants in Nigeria

Herbs and spices are used in all cultures as natural foodstuffs and for medicinal purposes. Siphonochilus aethiopicus, Monodora myristica and Crateva adansonii are some of the spices which are not commonly used. They improve the taste of food, and through their anti-oxidant, anti-microbial and anti-fungal properties, they could act as food preservatives. There is an accumulation of evidence for the usage of these spices medicinally as anti-inflammatory, anti-plasmodial, anti-sickling, anti-oxidant and chemopreventive agents. There have also been investigations to identify the active constituents of these spices and to verify their pharmacological actions. This article aims at reviewing the available data on these investigations and the basis for usage in several diseases and conditions

In vitro antimicrobial properties of friedelan-3-one from Pterocarpus santalinoides L’Herit, ex Dc

Chemical investigation of ethyl acetate leaf-extract of Pterocarpus santalinoides led to isolation of a friedelane-terpenoid. Structure elucidation was done by comparison of the Nuclear Magnetic Resonance (NMR) spectral features with literature data and was consistent with reported values for friedelan-3-one. The following microorganisms (Clinical isolates): methicillin resistant Staphylococcus aureus (MRSA), S. aureus, Corynebacterium ulcerans, Streptococcus pneumoniae, Campylobacter jejuni, Helicobacter pylori, Escherichia coli, Shigella dysenteriae, Candida tropicalis and Candida krusei were used for the in vitro antimicrobial activity. The isolated compound had Minimum Inhibition Concentration (MIC) value of 10 μg/ml for MRSA, H. pylori, E. coli and Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) of 40 μg/ml for E. coli; 20 μg/ml for MRSA, H. pylori and C. krusei; 10 μg/ml for S. aureus, S. pneumonia and C. tropicalis. It showed moderate antimicrobial activity against most of the pathogens tested. This is also the first report of the isolation of friedelan-3-one from this species.Key words: Friedelan-3-one, methicillin resistant Staphylococcus aureus (MRSA), Helicobacter pylori, Escherichia coli

Multi-target mode of action of a Clerodane-type diterpenoid from Polyalthia longifolia targeting African trypanosomes.

Natural products have made remarkable contributions to drug discovery and therapy. In this work we exploited various biochemical approaches to investigate the mode of action of 16-α-hydroxycleroda-3,13 (14)-Z-dien-15,16-olide (HDK-20), which we recently isolated from Polyalthia longifolia, on Trypanosoma brucei bloodstream trypomastigotes. HDK20 at concentrations ≥ EC50 (0.4μg/ml) was trypanocidal, with its efect irreversible after only a brief exposure time (<1h). Fluorescence microscopic assessment of DNA confguration revealed severe cell cycle defects after 8h of incubation with the compound, the equivalent of a single generation time. This was accompanied by DNA fragmentation as shown by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling (TUNEL) assays. HDK-20 also induced a fast and profound depolarisation of the parasites’ mitochondrial membrane potential and depleted intracellular ATP levels of T. brucei. Overall, HDK20 showed a multi-target mechanism of action, which provides a biochemical explanation for the promising antitrypanosomatid activity in our previous report

The individual components of commercial isometamidium do not possess stronger trypanocidal activity than the mixture, nor bypass isometamidium resistance

The four components present in the trypanocidal treatment Samorin, the commercially available formulation of isometamidium, were separated and purified by column chromatography. These compounds as well as the Samorin mixture and the other phenanthridine trypanocide, homidium, were tested on Trypanosoma congolense and wild type, diamidine- and isometamidium-resistant Trypanosoma brucei brucei strains using an Alamar blue drug sensitivity assay. EC50 values obtained suggest that M&B4180A (2) was the most active of the components, followed by M&B38897 (1) in all the strains tested, whereas M&B4596 (4) was inactive. Samorin was found to be significantly more active than any of the individual components alone, against T. congolense and all three T. b, brucei strains. Samorin and all its active constituents displayed reduced activity against the previously characterised isometamidium-resistant strain ISMR1

Hibiscus acid from hibiscus sabdariffa (malvaceae) has a vasorelaxant effect on the rat aorta

Hibiscus sabdariffa (Malvaceae) is a plant that is widely recognised for its antihypertensive properties; however the constituent(s) responsible for this biological activity are presently unknown. The aim of this study was to identify the potential compounds that are responsible for the vasorelaxant activity of H. sabdariffa. Thereafter, the mechanisms involved in producing the vasorelaxation were investigated. The plant was extracted consecutively with hexane, ethyl acetate and methanol. The methanolic extract was subjected to bioassay-guided fractionation in order to isolate pure compounds that possessed vasorelaxant activity. The vascular effects of the pure compounds were studied on the rat aorta in vitro using myography techniques. Hibiscus acid produced a concentration-dependent relaxation of the rat aorta pre-contracted with either phenylephrine (3 μM) or KCl (60 mM), irrespective of the presence of the endothelium. When the tissue was pre-contracted with phenylephrine, the concentration required to produce 50% relaxation (IC50), was 0.09 ± 0.01 mg/ml. Hibiscus acid had no effect on the phasic contraction induced by phenylephrine in Ca2+-free physiological solution; but it did affect the component of the contraction that is due to Ca2+ influx. In parallel studies, garcinia acid, a diastereoisomer of hibiscus acid, was found to have an almost identical vasorelaxant effect. The vasorelaxant action of both compounds is most likely due to the inhibition of Ca2+ influx via voltage-dependent Ca2+ channels

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist

The Strong Anti-Kinetoplastid Properties of Bee Propolis: Composition and Identification of the Active Agents and Their Biochemical Targets

The kinetoplastids are protozoa characterized by the presence of a distinctive organelle, called the kinetoplast, which contains a large amount of DNA (kinetoplast DNA (kDNA)) inside their single mitochondrion. Kinetoplastids of medical and veterinary importance include Trypanosoma spp. (the causative agents of human and animal African Trypanosomiasis and of Chagas disease) and Leishmania spp. (the causative agents of the various forms of leishmaniasis). These neglected diseases affect millions of people across the globe, but drug treatment is hampered by the challenges of toxicity and drug resistance, among others. Propolis (a natural product made by bees) and compounds isolated from it are now being investigated as novel treatments of kinetoplastid infections. The anti-kinetoplastid efficacy of propolis is probably a consequence of its reported activity against kinetoplastid parasites of bees. This article presents a review of the reported anti-kinetoplastid potential of propolis, highlighting its anti-kinetoplastid activity in vitro and in vivo regardless of geographical origin. The mode of action of propolis depends on the organism it is acting on and includes growth inhibition, immunomodulation, macrophage activation, perturbation of the cell membrane architecture, phospholipid disturbances, and mitochondrial targets. This gives ample scope for further investigations toward the rational development of sustainable anti-kinetoplastid drugs

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist

A review of the antimalarial, antitrypanosomal, and antileishmanial activities of natural compounds isolated from Nigerian flora.

The West African country Nigeria features highly diverse vegetation and climatic conditions that range from rain forest bordering the Atlantic Ocean in the South to the Desert (Sahara) at the Northern extreme. Based on data from the World Conservation Monitoring Center of the United Nations Environmental Protection, Nigeria, with ~5,000 documented vascular plants, ranks amongst the top 50 countries in terms of biodiversity. Such a rich biodiversity implies that the country is rich in diverse secondary metabolites—natural products/unique chemicals produced by the plant kingdom to confer selective advantages to them. Like many tropical countries, Nigeria is also endemic to numerous infectious diseases particularly those caused by parasitic pathogens. These phytochemicals have been exploited for the treatment of diseases and as a result, a new branch of chemistry, natural product chemistry, has evolved, to try to reproduce and improve the therapeutic qualities of particular phytochemicals. In this review, we have compiled a compendium of natural products, isolated from Nigerian flora, that have been reported to be effective against certain protozoan parasites with the aim that it will stimulate interests for further investigations, and give impetus to the development of the natural products into registered drugs. In total 93 structurally characterized natural compounds have been identified with various levels of anti-parasite activity mainly from Nigerian plants. The synthesis protocol and molecular target for some of these natural anti-parasite agents have been established. For instance, the anti-plasmodial compound fagaronine (7), a benzophenanthridine alkaloid from Fagara zanthoxyloides has been successfully synthesized in the laboratory, and the anti-trypanosomal compound azaanthraquinone (55) elicits its effect by inhibiting mitochondrial electron transfer in trypanosomes. This review also discusses the barriers to developing approved drugs from phytochemicals, and the steps that should be taken in order to accelerate the development of new antiparasitics from the highlighted compounds