Hepato-protective, antioxidant activities and acute toxicity of a stem bark extract of Erythrina senegalensis DC.

This study aimed at evaluating the in vitro antioxidant and hepatoprotective activities of different stem bark extracts of Erythrina senegalensis prepared with ethanol, and the in vivo hepatoprotective activity and acute toxicity of the best extract. The 2, 4-diphenyl-1-picryl-hydrazil (DPPH) and microsomal lipid peroxidation (MLP) models, and the rat liver slices system were respectively used for the in vitro study. The Methylene chloride/methanol (1:1 v/v) (Emc) and 40% ethanolic (E40) extracts were more efficient in inhibiting MLP and in scavenging DPPH radical. However, E40 was most effective with regards to lactate dehydrogenase (LDH) leakage inhibition from rat liver slices intoxicated with carbon tetrachloride (CCl4). The in vivo hepatoprotective activity was evaluated against CCl4-induced hepatotoxicity in rats. The E40 extract (100 mg/Kg) significantly reduced the increase in ALT, AST and lipid peroxidation in liver homogenate, showing that the extract is as protective as silymarin at the same dose. Acute toxicity was evaluated in mice and E40 did not produce any behavioural changes or mortality even at an oral dose of 16 g/kg. The extract was found to contain antioxidant classes of compounds (flavonoids and polyphenols). In conclusion, the E40 extract of E. senegalensis could be an important source of hepatoprotective compounds.Key words: Erythrina senegalensis, stem bark extract, antioxidant, hepatoprotective, carbon tetrachloride

3α-Hy­droxy­tirucalla-8,24-dien-21-oic acid

The title compound, C30H48O3, a triterpene isolated from the resin of canarium schweinfurthiiand, is an isomer of the previously reported triterpene 3α-hy­droxy­tirucalla-7,24-dien-21-oic acid [Mora et al. (2001 ▶). Acta Cryst. C57, 638–640], which crystallizes in the same trigonal space group. The title mol­ecule consists of four fused rings having chair, half-chair, half-chair and envelope conformations for rings A, B, C and D, respectively (steroid labelling). An intra­molecular C—H⋯O hydrogen bond generates an S(7) ring. In the crystal, mol­ecules are linked by O—H⋯O and C—H⋯O inter­actions, forming (001) sheets

A cocrystal of 3α-hy­droxy­tirucalla-8,24-dien-21-oic acid and 3β-fluoro­tirucalla-7,24-dien-21-oic acid (0.897:0.103)

The title compound, 0.897C30H48O3.0.103C30H47O2F is a co-crystal of two triterpenes isolated from the resin of Canarium schweinfurthiiand Engl. Both triterpenes consists of four trans-fused rings having chair/half-chair/half-chair and envelope conformations. The mol­ecular conformations are stabilized by intra­molecular C—H⋯O hydrogen bonds, forming rings of S(7) graph-set motif. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O and C—H⋯O inter­actions, forming sheets parallel to (001). All atoms. excepting the axially-oriented hydroxyl group in the major component and the equatorially-oriented fluorine atom in the minor component, are overlapping

Hepatoprotective and antioxidant activities of stem bark extract of Khaya grandifoliola (Welw) CDC and Entada africana Guill. et Perr

ABSTRACT Khaya grandifoliola (Meliaceae) and Entada africana (Fabaceae) are traditionally used as source of medicines against liver related diseases. But the most efficient solvent to extract the plants bioactive compounds has not yet been found. This work aimed at evaluating and comparing the hepatoprotective and antioxidant activities of Hexane (HE), methylenechloride-methanol (MCME) and water (WE) extracts of the plants stem bark. The hepatoprotective activity was evaluated by acetaminopheninduced damage in rat liver slices in measuring lactate dehydrogenase (LDH) leakage as toxicity marker. The antioxidant activity was assessed by using 2, 4-diphenyl-1-picryl-hydrazil (DPPH), β-carotene-linoleic acid system (β-CLAMS) and microsomal lipid peroxidation (MLP) assays. The MCME extract of both plants efficiently decreased LDH leakage from liver slices. At the tested concentration of 100µg/ml, the hepatoprotective percentage of the extract of K. grandifoliola (87.15%) and that of silymarine (93.73%) were comparable. In the antioxidant study, the MCME and WE extracts of both plants performed well in inhibiting MLP assay but, the MCME extracts were the more antioxidant with IC 50 values of 2.7±0.05µg/ml and 0.50±0.07µg/ml comparable with Trolox (2.27±0.52µg/ml) for K. grandifoliola and E. africana, respectively. Phytochemically, many classes of compounds including polyphenols were tested positive in the MCME extracts. From the interesting activity of these extracts, it might be concluded that methylenechloride-methanol (1:1v/v) mixture is the most efficient solvent to extract hepatoprotective and antioxidant active principles from K. grandifoliola and E. africana stem bark

Traditional Medicine: Past, present and future research and development prospects and integration in the National Health System of Cameroon

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the  strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country.Key words: Tradttional medicine, Cameroon

Phytotoxicity of alkaloids, coumarins and flavonoids isolated from 11 species belonging to the Rutaceae and Meliaceae families

Meliaceae and Rutaceae families are known for the high diversity of their secondary metabolites, which include many groups that represent a rich source of structural diversity, and are good candidates as sources of allelochemicals that could be useful in agriculture. In the work described here the bioactivity profiles were evaluated for 3 alkaloids (1–3), 12 coumarins (4–15), 2 phenylpropanoic acid derivatives (16 and 17) and 14 flavonoids (18–31) from 11 species belonging to the Meliaceae and Rutaceae families. All compounds were tested in the wheat coleoptile bioassay and those that showed the highest activities were tested on the STS (Standard Target Species) Lepidium sativum (cress), Lactuca sativa (lettuce), Lycopersicon esculentum (tomato), and Allium cepa (onion). Most of the isolated compounds showed phytotoxic activity and graveoline (3), psoralen (8), and flavone (18) were the most active, with bioactivity levels similar to that of the commercial herbicide Logran1. The results indicate that these compounds could be involved as semiochemicals in the allelopathic interactions of these plant species

CHEMISTRY AND BIOLOGICAL EVALUATION OF CAMEROONIAN DORSTENIA SPECIES

Research in the area of natural products is an important scientific activity in Cameroon where a large variety of plants, especially, Dorstenia spp are used as anti-snakebite, anti-infection and anti-rheumatism remedies in medicinal plant therapy. The genus is recognized as a rich source of prenyl and geranyl-substituted coumarins and flavonoids [1]. There is now increasing interest in this genus. Almost 40 papers have appeared during the last decade, reporting on research results on over 25 Dorstenia species. As part of our program to study the chemical constituents of African Dorstenia species [1] we have investigated 14 species from Cameroon. More than hundred secondary metabolites, of which thirty are new derivatives, were isolated using various chromatographic techniques (VLC, CC, PTLC), and characterized using extensive spectroscopic methods. These compounds are regrouped into: triterpenoids, styrenes, coumarins and mainly flavonoids [1]. 3, 3’- bis [3, 7-Dimethyl-2, 6-octadienyl]-4, 5, 2’, 4’-tetrahydroxylchalcone, isolated from the twigs of D. prorepens, is the first example of a bis-geranylated chalcone. Eleven diprenylated flavonoids have so far been isolated from Dorstenia and all of them are reported to be isolated from the twigs of D. mannii [1]. D. psilurus provided triprenylated flavonoids with two units in ring A and one in ring B [1]. The pharmacological data of this genus is scanty. Extracts and/or compounds from the investigated species show anti-inflammatory, analgesic, anti-oxidant and antimalarial activities [2]. Inhibition of matrix-metalloproteinase-2 secretion from brain tumour cells suggests chemo-preventive properties of furanocoumarin glucoside and chalcones isolated from D. turbinata [3]. To the best of our knowledge, prenylated flavonoids have only been reported from African Dostenia species so far. References: [1] Abegaz B.M., Ngadjui B.T et al. 2000, Current Organic Chemistry, 4, 1079-1090. [2] Ngameni B., Watchueng J. et al., 2007, Arkivoc (XIII) 116-123 [3] Ngameni B. Touaibia M. et al, 2007, Phytochemistry, 67, 2573-257