Antileishmanial and Antiplasmodial Activities of Secondary Metabolites from the Root of Antrocaryon klaineanum Pierre (Anacardiaceae).

Antrocaryon klaineanum is traditionally used for the treatment of back pain, malaria, female sterility, chlamydiae infections, liver diseases, wounds, and hemorrhoid. This work aimed at investigating the bioactive compounds with antileishmanial and antiplasmodial activities from A. klaineanum. An unreported glucocerebroside antroklaicerebroside (1) together with five known compounds (2-6) were isolated from the root barks of Antrocaryon klaineanum using chromatographic techniques. The NMR, MS, and IR spectroscopic data in association with previous literature were used for the characterization of all the isolated compounds. Compounds 1-4 are reported for the first time from A. klaineanum. The methanol crude extract (AK-MeOH), the n-hexane fraction (AK-Hex), the dichloromethane fraction (AK-DCM), the ethyl acetate fraction (AK-EtOAc), and compounds 1-6 were all evaluated for their antiparasitic effects against Plasmodium falciparum strains susceptible to chloroquine (3D7), resistant to chloroquine (Dd2), and promastigotes of Leishmania donovani (MHOM/SD/62/1S). The AK-Hex, AK-EtOAc, AK-MeOH, and compound 2 were strongly active against Dd2 strain with IC50 ranging from 2.78 ± 0.06 to 9.30 ± 0.29 µg/mL. Particularly, AK-MeOH was the most active-more than the reference drugs used-with an IC50 of 2.78 ± 0.06 µg/mL. The AK-EtOAc as well as all the tested compounds showed strong antileishmanial activities with IC50 ranging from 4.80 ± 0.13 to 9.14 ± 0.96 µg/mL.

Bioactive Clerodane Diterpenoids from the Leaves of Casearia coriacea Vent.

Casearia coriacea Vent., an endemic plant from the Mascarene Islands, was investigated following its antiplasmodial potentialities highlighted during a previous screening. Three clerodane diterpene compounds were isolated and identified as being responsible for the antiplasmodial activity of the leaves of the plant: caseamembrin T (1), corybulosin I (2), and isocaseamembrin E (3), which exhibited half maximal inhibitory concentrations (IC50) of 0.25 to 0.51 µg/mL. These compounds were tested on two other parasites, Leishmania mexicana mexicana and Trypanosoma brucei brucei, to identify possible selectivity in one of them. Although these products possess both antileishmanial and antitrypanosomal properties, they displayed selectivity for the malaria parasite, with a selectivity index between 6 and 12 regarding antitrypanosomal activity and between 25 and 100 regarding antileishmanial activity. These compounds were tested on three cell lines, breast cancer cells MDA-MB-231, pulmonary adenocarcinoma cells A549, and pancreatic carcinoma cells PANC-1, to evaluate their selectivity towards Plasmodium. This has not enabled us to establish selectivity for Plasmodium, but has revealed the promising activity of compounds 1-3 (IC50 < 2 µg/mL), particularly against pancreatic carcinoma cells (IC50 < 1 µg/mL). The toxicity of the main compound, caseamembrin T (1), was then evaluated on zebrafish embryos to extend our cytotoxicity study to normal, non-cancerous cells. This highlighted the non-negligible toxicity of caseamembrin T (1).

Disruption of Biofilm Formation and Quorum Sensing in Pathogenic Bacteria by Compounds from Zanthoxylum Gilletti (De Wild) P.G. Waterman.

Microbial resistance is facilitated by biofilm formation and quorum-sensing mediated processes. In this work, the stem bark (ZM) and fruit extracts (ZMFT) of Zanthoxylum gilletii were subjected to column chromatography and afforded lupeol (1), 2,3-epoxy-6,7-methylenedioxyconiferyl alcohol (3), nitidine chloride (4), nitidine (7), sucrose (6) and sitosterol-ß-D-glucopyranoside (2). The compounds were characterized using MS and NMR spectral data. The samples were evaluated for antimicrobial, antibiofilm and anti-quorum sensing activities. Highest antimicrobial activity was exhibited by compounds 3, 4 and 7 against Staphylococcus aureus (MIC 200 µg/mL), compounds 3 and 4 against Escherichia coli (MIC = 100 µg/mL) and compounds 4 and 7 against Candida albicans (MIC = 50 µg/mL). At MIC and sub-MIC concentrations, all samples inhibited biofilm formation by pathogens and violacein production in C. violaceum CV12472 except compound 6. Good disruption of QS-sensing in C. violaceum revealed by inhibition zone diameters were exhibited by compounds 3 (11.5 ± 0.5 mm), 4 (12.5 ± 1.5 mm), 5 (15.0 ± 0.8 mm), 7 (12.0 ± 1.5 mm) as well as the crude extracts from stem barks (16.5 ± 1.2 mm) and seeds (13.0 ± 1.4 mm). The profound inhibition of quorum sensing mediated processes in test pathogens by compounds 3, 4, 5 and 7 suggests the methylenedioxy- group that these compounds possess as the possible pharmacophore.

Secondary metabolites from Detarium microcarpum Guill. and Perr. (Fabaceae).

The chemical investigation of the ethanol/water (7:3) extract of the roots of Detarium microcarpum (Fabaceae) led to the isolation of one new labdane diterpenoid, microcarpin (1) and one new ceramide derivative, microcarpamide (2), along with eight known secondary metabolites (3-10) including, 5-(carboxymethyl)-5,6,8a-trimethyl-3,4,4a,5,6,7,8,8a-octahydronaphthalene-1-carboxylic acid (3), microcarposide (4), rhinocerotinoic acid (5), 1,7-dihydroxy-6-methylxanthone (6), ursolic acid (7), 3ß,23-dihydroxylup-20(29)-en-28-oic acid (8), alphitolic acid (9), and stigmasterol glucoside (10). The structures of these compounds were elucidated based on their spectroscopic data. Although compounds 3 and 4 are known, their crystalline structures are reported here for the first time. These compounds were evaluated in vitro for their antisalmonella activity. The results obtained showed that, microcarpamide (2), microcarposide (4), and rhinocerotinoic acid (5) were moderately active against three salmonella strains: Salmonella typhi, Salmonella enteritidis and Salmonella typhimirium, with minimum inhibition concentration values of 76.7 and 153.5 µM.

Antimicrobial and α-glucosidase inhibitory activities of chemical constituents from Gardenia aqualla (Rubiaceae).

An aliphatic alkene namely pentapentacontene (4) was isolated for the first time from a natural source, Gardenia aqualla, along with fourteen other compounds including nonacosanol (1), tetratriacontanol (2), octatriacontanol (3), ß-sitosterol (5) and stigmasterol (6), daucosanol (7), ursolic acid (8), uvaol (9), 3ß,19α,23ß,24α-tetrahydroxyurs-12-en-28-oic acid (10), lupenone (11), oleanolic acid (12), vanillin (13), vanillic acid (14) and D-mannitol (15). α-glucosidase inhibitory assay revealed that MeOH and EtOAc extracts of leaves had the best activity with IC50 of 9.65 and 20.03 µg/ml respectively. All the tested compounds showed dose dependent inhibition of α-glucosidase and some of them were found to be comparable to acarbose. Compound 10 was the most potent with IC50 = 1.72 µM. It also showed the most interesting antibacterial activity, against the isolate strain of S. typhi and P. aeruginosa and also exhibited the most significant antifungal activities against all the tested yeasts.

A new isoquinoline and ceramide from the stem barks of Discoglypremna caloneura (Pax) Prain (Euphorbiaceae) with antiproteinase and cytotoxic activities.

Two new compounds, an isoquinoline (1) and caloneuramide (2), a ceramide were isolated from the stem bark of Discoglypremna caloneura together with seven known compounds namely aurantiamide acetate (3), acetylaleuritolic acid (4), 3α-hydroxylaleuritolic acid 2α-p-hydroxybenzoate (5), mixture of stigmasterol (6) and ß-sitosterol (7), mixture of 7-oxo-stigmasterol (8) and 7-oxo-ß-sitosterol (9). Their structures were determined based on data from literature and spectroscopic methods. Derivatization reactions on the isoquinoline led to two new compounds, the methylated (10) and acetylated (11) derivatives. Some compounds and extracts were evaluated for their cytotoxic and antiproteinase activity. Antiproteinase effect of compounds 1, 10 and 11 exhibited IC50 values of 10.77, 1.19 and 3.61 µg/mL respectively; significantly low compared to the standard drug, acetyl salicylic acid (IC50 = 20.28 µg/mL). Ethyl acetate and methanol extract exhibited moderate cytotoxicity activity on Chang liver cells with CC50 values of 167.90 ± 2.20 and 106.30 ± 2.03 µg/mL compared to the reference drug cucurmin (CC50 = 11.05 ± 1.04 µg/mL).

Bioassay-guided isolation of vilasinin-type limonoids and phenyl alkene from the leaves of Trichilia gilgiana and their antiplasmodial activities.

Bioassay-guided fractionation of the CH2Cl2-MeOH (1:1) leaves extract of Trichilia gilgiana, yielded two new vilasinin-type limonoids named gilgianin A (1) and gilgianin B (2), one new phenyl alkene derivative designated as gilgialkene A (3), along with six known compounds: rubescin H (4), TS3 (5), trichirubine A (6), sitosteryl-6'-O-undecanoate-ß-D-glucoside (7), scopoletin (8), and octadecane-2-one (9). Their structures were elucidated based on spectroscopic analysis and comparison with literature data. Compounds 5 and 6 exhibited the highest antiplasmodial activity with IC50 values of 1.14 and 1.32 µM respectively. Moreover, compound 5 was very cytotoxic with CC50 value of 0.88 µM, compared to compound 6, which was not cytotoxic (CC50 > 10 µg/mL). Compounds 1 (IC50 = 9.84 µM), 2 (IC50 = 11.04 µM) and 4 (IC50 = 10.71 µM) presented good antiplasmodial activity while also exhibiting significant cytotoxicity, with CC50 values ranging from of 14.45 to 29.7 µM.[Formula: see text].

Pentas longiflora Oliv. (Rubiaceae), a plant used in the treatment of Pityriasis Versicolor in Rwanda: Chemical composition and standardization of leaves and roots.

In Rwanda, the roots of Pentas longiflora Oliv. (Rubiaceae) have been used for a long time to treat Pityriasis versicolor. However, many people reported the use of leaves instead of roots. This research was conducted to compare the phytochemical composition and establish chromatographic methods for the standardization of roots and leaves extracts of P. longiflora. During this process, three new pentalongin glycosides (pentalonginoside A, pentalonginoside B, and pentalonginoside C) and two known glycosides of the same type (harounoside and clarinoside), as well as rutin, luteolin-7-rutinoside were isolated from methanol extract of leaves. In addition, pentalongin and psychorubrin, previously isolated from ethylacetate roots extract, were also identified in Pentas longiflora ethylacetate leaves extract. The presence of the antifungal compound pentalongin in leaves may explain the traditional use of leaves in the treatment of Pytiriasis versicolor. Furthermore, harounoside, psychorubrin, and pentalongin were selected as markers for HPLC fingerprints of MeOH extract. The accuracy and risk profile demonstrated the reliability of the validated method. In general, considerable variations of concentration in plant metabolites, including pentalongin, were observed between samples from different sites. The content in pentalongin (expressed as juglone) in collected samples ranged between 1.7 and 70.0 mg/100 g. The highest concentration (70.0 ± 17 mg/100 g) was registered in the cultivated samples from Mukoni. This important variation of pentalongin concentrations according to sampling sites, shows that in order to guarantee equivalent efficacy, finished products with P. longiflora should be standardized based on their pentalongin content.

Cafeteria Diet-Induced Metabolic and Cardiovascular Changes in Rats: The Role of Piper nigrum Leaf Extract.

BACKGROUND: Cafeteria diet is known to induce excessive body fat accumulation (obesity) that could cause metabolic and cardiovascular changes and even death. The increase in prevalence over time and the failure in treatment options make obesity a real public health problem. The present study assessed the preventive effect of the hydro-ethanolic extract of the Piper nigrum leaf on the development of metabolic and cardiovascular changes in cafeteria diet fed Wistar rats. METHODS: Thirty-six male rats were divided into 5 groups of 6 rats each: a normal control group (Nor.), a negative control group (Neg.), two groups administered different doses of extract in mg/kg (E250 and E500), and a group administered atorvastatin 10 mg/kg (Ator., reference drug). The animals were fed with experimental diets (standard and cafeteria) for a period of 5 weeks. Food and water intake were assessed daily, and the body weight assessed weekly. At the end of the feeding, plasma lipid profile and markers of hepatic and renal function were assessed. Furthermore, the relative weights of the adipose tissue and the organs were assessed. The liver, kidneys, and heart homogenates were assessed for markers of oxidative stress while the aorta was histopathologically examined. RESULTS: Cafeteria diet-induced weight gain of 30% and increased triglyceride, total cholesterol, and low-density lipoprotein cholesterol level of more than 50%. Equally, an increase in the relative weight of accumulated adipose tissues of more than 90%, oxidative stress, and alteration in the organ structure were visible in cafeteria diet fed rats (Neg). Treatment with P. nigrum extract significantly prevented weight gain, dyslipidemia, oxidative stress, and alteration in the architecture of the aorta. The effect of P. nigrum extract was comparable to that of the reference drug. CONCLUSION: Piper nigrum leaf may prevent weight gain and possess cardioprotective activity with a strong antioxidant activity.

Phytochemical Investigation and Biological Activities of Lantana rhodesiensis.

Lantana rhodesiensis Moldenke is a plant widely used to treat diseases, such as rheumatism, diabetes, and malaria in traditional medicine. To better understand the traditional uses of this plant, a phytochemical study was undertaken, revealing a higher proportion of polyphenols, including flavonoids in L. rhodesiensis leaf extract and moderate proportion in stem and root extracts. The antioxidant activity of the extracts was also determined using three different assays: the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, the FRAP method (Ferric-reducing antioxidant power) and the ß-carotene bleaching test. The anti-malarial activity of each extract was also evaluated using asexual erythrocyte stages of Plasmodium falciparum, chloroquine-sensitive strain 3D7. The results showed that the leaf extract exhibited higher antioxidant and anti-malarial activities in comparison with the stem and root extracts, probably due to the presence of higher quantities of polyphenols including flavonoids in the leaves. A positive linear correlation was established between the phenolic compound content (total polyphenols including flavonoids and tannins; and total flavonoids) and the antioxidant activity of all extracts. Furthermore, four flavones were isolated from leaf dichloromethane and ethyl acetate fractions: a new flavone named rhodescine (5,6,3',5'-tetrahydroxy-7,4'-dimethoxyflavone) (1), 5-hydroxy-6,7,3',4',5'-pentamethoxyflavone (2), 5-hydroxy-6,7,3',4'-tetramethoxyflavone (3), and 5,6,3'-trihydroxy-7,4'-dimethoxyflavone (4). Their structures were elucidated by 1H, 13CNMR, COSY, HSQC, HMBC, and MS-EI spectral methods. Aside from compound 2, all other molecules were described for the first time in this plant species.

The Inhibition of NLRP3 Inflammasome and IL-6 Production by Hibiscus noldeae Baker f. Derived Constituents Provides a Link to Its Anti-Inflammatory Therapeutic Potentials.

The activation of NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome and/or its components is associated with the physio-pathogenesis of many respiratory diseases including asthma, COPD (chronic obstructive pulmonary disease), SARS Cov-2 (severe acute respiratory syndrome coronavirus 2), and in several autoimmune diseases. Hibiscus noldeae Baker f. has been widely reported to be traditionally used in the treatment of different ailments, some of which are of inflammatory background such as asthma, wounds, headache, etc. However, the claims have not been supported by evidence at the molecular and functional levels. Here, we report on the bio-guided fractionation of H. noldeae and assessment of the inhibitory properties of some fractions and purified compounds on NLRP3 inflammasome and Interleukin 6 (IL-6). The activation of the NLRP3 inflammasome was determined by detecting the activity of caspase-1 and the production of Interleukin 1ß (IL-1ß) in Lipopolysaccharide (LPS) and ATP-stimulated Tamm-Horsfall Protein 1 (THP-1) macrophages, while the production of IL-6 was studied in LPS-stimulated RAW264.7 mouse macrophages. It was observed that hexane and ethyl acetate fractions of the crude extract of the aerial parts of H. noldeae, as well as caffeic acid, isoquercetin, and ER2.4 and ER2.7 fractions revealed significant inhibitory effects on Caspase-1 activities, and on IL-1ß and IL-6 production. The ER2.4 and ER2.7 fractions downregulated the production of IL-1ß and IL-6, in a similar range as the caspase-1 inhibitor AC-YVAD-CHO and the drug Dexamethasone, both used as controls, respectively. Overall, our work does provide the very first scientific based evidence for Hibiscus noldeae anti-inflammatory effects and widespread use by traditional healers in Rwanda for a variety of ailments.

Bioguided identification of daucosterol, a compound that contributes to the cytotoxicity effects of Crateva adansonii DC (capparaceae) to prostate cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Crateva adansonii DC (Capparaceae) is a shrub used to treat tumors in Cameroon. In our previous reports, a Crateva adansonii dichloromethane-methanol (DCM/MeOH) extract was shown to prevent chemically induced tumors in Wistar rats. AIM OF STUDY: To determine the bioactive principle of Crateva adansonii extract and to elucidate its underlying mechanism. MATERIALS AND METHODS: An activity-guided fractionation was realized using MTT assay. To investigate if the bioactive compound daucosterol (CA2) accounted for the previously observed anticancer effects of the C. adansonii extract, it was tested on cell growth, cell proliferation, cell cycle, cell death mechanism and cell migration. In addition, cell cycle- and apoptosis-regulating proteins were assessed by Western blotting. RESULTS: Daucosterol (CA2), a steroid saponin, was identified as major anticancer principle of the C. adansonii extract. Daucosterol significantly inhibited LNCaP, DU145 and PC3 prostate carcinoma cell growth and proliferation at the optimal concentration of 1 µg/mL. It also significantly increased the number of late apoptotic (DU145) and apoptotic (PC3) cells. The number of cells in S phase increased in DU145, while the number of G0/G1 cells decreased. Cell cycle proteins (cdk1, pcdk1, cyclin A and B) were down-regulated in DU145 and PC3 cells, whereas only cdk2 was down-regulated in PC3 cells. Moreover, the anti-apoptotic Akt, pAKT and Bcl-2 proteins were down-regulated, while the pro-apoptotic protein Bax was up-regulated. CA2 induced anti-metastatic effects by decreasing chemotaxis and cell migration, while it increased cell adhesion to fibronectin and collagen matrix. CONCLUSION: These results suggest that daucosterol is the major active principle responsible at least in part for the anticancer effect of the extract of Crateva adansonii.

Excelsanone, a new isoflavonoid from Erythrina excelsa (Fabaceae), with in vitro antioxidant and in vitro cytotoxic effects on prostate cancer cells lines.

A new isoflavonoid, excelsanone (2), was isolated from the ethyl acetate extract of Erythrina excelsa stem bark, together with three known compounds namely 6,8-diprenylgenistein (3), ß-sitosterol (1) and sitosteryl-ß-D-glucopyranoside (4). Their structures were elucidated using spectroscopic methods (HR-ESI-MS, NMR and IR) and by comparison with some literature data. The antioxidant activity of crude extracts and two isolated compounds was evaluated using free radical scavenging (DPPH) and Ferric Reducing Ability Power (FRAP) methods with catechin as standard. The results of the radical scavenging activity showed that excelsanone (2) has a moderate potential with an IC50 of 1.31 mg/ml. The cytotoxicity of compounds 2 and 3 as well as the ethyl acetate extract was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in two prostate cancer cell lines (DU145 and PC3). Excelsanone (2) induced a greater cytotoxicity in all tested cell lines, with a significant inhibition of DU145 cells growth in a concentration-dependent manner.

Cytotoxicity, antimicrobial and antioxidant activity of eight compounds isolated from Entada abyssinica (Fabaceae).

BACKGROUND: Entada abyssinica is a plant traditionally used against gastrointestinal bacterial infections. Eight compounds including three flavonoids, three terpenoids, a monoglyceride and a phenolic compound isolated from E. abyssinica were investigated for their cytotoxicity, antibacterial and antioxidant activity. RESULTS: Compounds 7 and 2 had remarkable activity against Salmonella typhimurium with the lowest respective minimum inhibitory concentration (MIC) values of 1.56 and 3.12 µg/mL. The antioxidant assay gave IC50 values varied from 0.48 to 2.87 µg/mL in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, from 2.53 to 17.04 µg/mL in the 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assay and from 1.43 to 103.98 µg/mL in the FRAP assay. Compounds had relatively low cytotoxicity (LC50 values ranging from 22.42 to 80.55 µg/mL) towards Vero cells. Ursolic acid had the most potent cytotoxicity against THP-1 and RAW 264.7 cells with LC50 values of 9.62 and 4.56 µg/mL respectively, and selectivity index values of 7.32 and 15.44 respectively. CONCLUSION: Our findings suggest that among the terpenoid and flavonoid compounds studied, entadanin (compound 7) possess tremendous antibacterial activity against S. typhimurium and could be developed for the treatment of bacterial diseases.

Antiplasmodial activity of Mezoneuron benthamianum leaves and identification of its active constituents.

ETHNOPHARMACOLOGICAL RELEVANCE: Decoctions of the leaves of M. benthamianum Baill. are used by traditional healers in Guinea to treat malaria and this use was validated by a preliminary clinical assay. AIM OF THE STUDY: To evaluate the in vitro antiplasmodial activity and to identify active compounds from extracts of M. benthamianum leaves. MATERIAL AND METHODS: Antiplasmodial activity of extracts, fractions and pure compounds was evaluated in vitro against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) using the measurement of the plasmodial lactate dehydrogenase activity. Selectivity of extracts and purified compounds for Plasmodium parasites was evaluated by using WST-1 test on HeLa human cells. Compounds were isolated using normal phase silica gel column chromatography and prepHPLC and their structures elucidated using extensive spectroscopic analysis. RESULTS: Hydroethanolic extracts (70% v/v) of M. benthamianum leaves showed a moderate in vitro activity against P. falciparum 3D7, with IC50 in the range 22.5 - 32.6µg/mL, depending on the batch; while a dark precipitate formed during ethanol evaporation showed higher activity (IC50 =6.5µg/mL). The fractionation was performed on this most active fraction and was followed by in vitro antiplasmodial assay. Active compounds (5, 7, 8) belong to several phytochemical classes, contributing together to the global antiplasmodial activity of the hydroethanolic extract against P. falciparum parasite. This study finally allowed the isolation of three diterpenes including two new compounds named Mezobenthamic acids A (1) and B (2) and neocaesalpin H (3), as well as quercetin (4), kaempferol (7), resveratrol (6), gallic acid (9) and its ethylester (5), ß-sitosterol glucoside (10) and 13b-hydroxy-pheophorbide a (8). CONCLUSION: This study gives some concrete evidence to support the ethnopharmacological use of Mezoneuron benthamianum leaves extract in the management of malaria. The active compounds can be further studied for their antiplasmodial potential, as well as their suitability to be used as quality markers for the standardization of this herbal drug from the Guinean traditional pharmacopeia.

Antiplasmodial activity of Heinsia crinita (Rubiaceae) and identification of new iridoids.

ETHNOPHARMACOLOGICAL RELEVANCE: Heinsia crinita is used in traditional medicine for the treatment of febrile illness and erectile dysfunction. Its stem bark powder is found in some peripheral markets in the Democratic Republic of the Congo (DRC) as a remedy against malaria. Investigations were conducted on crude extracts of leaves, fruits and stem barks in view to validate their use and to determine which plant part possesses the best antiplasmodial properties. MATERIALS AND METHODS: Different plant parts were extracted with methanol, ethanol and dichloromethane. Based on the preliminary assays, the dichloromethane extract of the stem bark was subjected to fractionation using preparative HPLC system and column chromatography. This step led to the isolation of two new iridoids which had their structures elucidated by NMR, UV, MS and FT-IR spectroscopic techniques. Extracts and pure compounds were tested in vitro against the 3D7 strain of Plasmodium falciparum. The inhibition of the parasite growth was evaluated in vitro by colorimetric method (p-LDH assay) and their cytotoxicity evaluated in vitro against the human non-cancer fibroblast cell line (WI38) through WST1 assay. The in vivo antiplasmodial activity was assessed by the inhibition of Plasmodium berghei growth in infected mice treated with the ethanol extract of H. crinita stem bark at the concentrations of 200 and 300mg/Kg/day per os, using a protocol based on the 4-d suppressive test of Peters and compared to a non-treated negative control group of mice (growth =100%). Finally the antioxidant activity of the same extract was evaluated using ABTS, DPPH and cell-based assays. RESULTS: A moderate in vitro antiplasmodial activity was observed for the dichloromethane extract of the stem bark of H. crinita (IC50 =29.2±1.39µg/mL) and for the two new iridoids, lamalbide 6, 7, 8- triacetate (IC50 =16.39±0.43µg/mL) as well as for its aglycone lamiridosin 6, 7, 8-triacetate (IC50 =0.44.56±1.12µg/mL). The ethanolic stem bark extract (200 and 300mg/kg/day, oral route) showed a moderate in vivo antimalarial activity in Plasmodium berghei-infected mice with 27.84±2.75% and 48.54±3.76% of inhibition of the parasite growth, respectively (p<0.01).). This extract displayed high cellular antioxidant activity using dichlorofluorescein-diacetate (DCFDA) on HL-60 monocytes. These crude extracts and pure compounds tested at the higher concentration of 100µg/mL did not show any cytotoxicity against WI38 cells. CONCLUSIONS: The results showed that H. crinita extracts possess antimalarial activity and contain some unusual iridoids with moderate antiplasmodial activity, therefore justifying to some extent its traditional use by the local population in DRC for this purpose. This is the first report of the isolation and antiplasmodial activity of these two new iridoids.

Evaluation of the antidiabetic and antioxidant properties of Morinda lucida stem bark extract in streptozotocin intoxicated rats.

The present research evaluated the antidiabetic and antioxidant properties of M. lucida stem bark (50 and 500mg/kg) and glibenclamide (25mg/kg, standard drug) in acute (Oral glucose tolerance test) and sub-acute (Streptozotocin 60mg/kg, i.p. diabetic model) administration. A group of healthy rats constituted the normal control. The sub-acute experiment lasted 28 days during which water, food intake and weight gain were measured and biochemical parameters analyzed in both plasma and erythrocytes at the end of the experiment. The chemical substances present in M. lucida bark extract were determined. In the Oral glucose tolerance test, the reduction of blood glucose level was statistically significant for both M. lucida extracts and glibenclamide. However, in the diabetic rats acute administration of 500mg/kg extract had better blood sugar lowering effect than glibenclamide, which was better than 50mg/kg extract. Streptozotocin diabetic animal model was characterized by a decrease in weight gain, erythrocyte SOD and CAT activities and an increase in water and food consumption, lipid peroxidation, cholesterol, triglycerides, plasma glucose, creatinine and urea concentrations, and transaminases activities. M. lucida extract and glibenclamide significantly prevented the alteration of these parameters, thus indicating a corrective effect on diabetes and its complications. This study justifies the traditional claim and provides a rationale for the use of M. lucida to treat diabetes. Its antioxidant properties may serve to curb oxidative stress and hence prevent the diabetic complications related to oxidative stress. Chemical substances, which may be accountable for the antidiabetic and antioxidant properties of M. lucida were detected in the aqueous extract of M. lucida bark.

Chemical composition, in vitro antioxidant and anti-inflammatory properties of essential oils of four dietary and medicinal plants from Cameroon.

BACKGROUND: In the Cameroonian traditional medicine, plants of the Capparidaceae, Euphorbiaceae and Liliaceae families are used to treat several metabolic diseases. These plants are rich in various compounds belonging to the glucosinolates and thiosulfinates family. Till date, very little studies have been done aiming at assessing the antioxidant and inflammatory properties of the essential oils (EOs) of these plants. Essential oils are volatile extracts produced by secondary metabolism. They are usually constituted of terpens and may also contain specific non terpenic components such as glucosinolates and thiosulfinates for the species that are being considered in the present study. This study highlights and compares the chemical composition, antioxidant and anti-inflammatory properties of the essential oils of the stem barks of Drypetes gossweileri (Euphorbiaceae), roots of Pentadiplandra brazzeana (Capparidaceae), red bulbs of Allium cepa and Alium sativum (Liliaceae) collected in Cameroon (Central Africa). METHODS: The essential oils were extracted by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). In vitro antioxidant activities were determined using the radical scavenging assay, total phenolic content, ferric reducing antioxidant power (FRAP) assay and determination of antioxidant activity index (AAI) according to the method described by Scherer and Godoy. The anti-inflammatory activities were evaluated using albumin denaturation method. Differences (p < 0.05) between the experimental and the control groups were evaluated using one way analysis of variance (ANOVA) followed by Tukey's test for multiple comparisons. RESULTS: The main components of Allium sativum essential oil were diallyl trisulfide (41.62 %), diallyl disulfide (19.74 %), allyl methyl trisulfide (12.95 %), diallyl sulfide (7.1 %) and diallyl tetrasulfide (4.22 %). Those of Allium cepa essential oil were diallyl trisulfide (22.17 %), dipropyl trisulfide (11.11 %), 2-methyl-3,4-dithiaheptane (9.88 %), methyl propyl trisulfide (8.14 %), dipropyl tetrasulfide (8.07 %) and 2-propenyl propyl disulfide (5.15 %). Drypetes gossweileri and Pentadiplandra brazzeana essential oils presented similar chemical compositions as compared with benzylisothiocyanate content (63.19 and 97.63 % respectively), but differed in benzylcyanide content (35.72 and 0.86 % respectively). The essential oils were rich in phenolic compounds in the following order Allium sativum < Allium cepa < D. gossweileiri < P. brazzeana. The essential oils exhibited high antioxidant and DPPH radical scavenging effect but low ferric reducing power activity. Moreover, the four essential oils showed anti-inflammatory activities (by heat denaturation of Bovine Serum Albumin). The anti-inflammatory activities of P. brazzeana and A. cepa essential oils were comparable but higher than those of D. gossweileri and sodium diclofenac used as a reference non-steroidal anti-inflammatory drug. CONCLUSION: The essential oils of the plants were rich in organosulfur compounds. These compounds were probably responsible for their appreciable antioxidant and anti-inflammatory activities. Due to their antioxidant and anti-inflammatory properties, the essential oils of some of these plants might be used as natural additives in the pharmaceutical, cosmetic and agro-industries.

Ericoside, a new antibacterial biflavonoid from Erica mannii (Ericaceae).

A new dihydroflavonol-flavonol biflavonoid derivative, named ericoside was isolated from the ethanol extract of the whole plant of Erica mannii along with the known flavonoid, taxifolin 3-O-α-L-rhamnopyranoside; and two readily available sterols (sitosterol, sitosterol 3-O-ß-D-glucopyranoside). The isolation was performed using chromatographic methods and the structure of purified molecules were elucidated using spectroscopic techniques (e.g. MS, NMR) and by comparison with literature data. The crude ethanol extract, ericoside, and taxifolin 3-O-α-L-rhamnopyranoside were tested against ten Gram-negative bacteria including multidrug resistant clinical isolates using a broth microdilution method. The crude ethanol extract showed no noteworthy activity. Of the purified compounds, ericoside displayed moderate activity against the resistant Escherichia coli AG100 with a MIC of 64 µg/mL.

New Approach for the Development of Improved Traditional Medicine: Case of a Preparation of an Oral Hypoglycemic Medicine from Laportea ovalifolia (Schumach. & Thonn.) Chew. (Urticaceae).

A majority of Africans rely on traditional medicine as the primary form of health care. Yet most traditional medicine products have a short shelf life, especially for water-based formulations such as macerations, infusions and decoctions. Indeed, many of these water extracts become unfit for human consumption after five to seven days of conservation either because of the degradation or toxicity of active components, and/or the growth of pathogenic organisms. The purpose of this study was to describe and apply a new approach for the development of an improved traditional medicine (ITM) that is cheap, very efficient, not toxic, and easy to produce, and that can be conserved for a longer time without a significant loss of activity. Hence, Laportea ovalifolia was selected from an ethnobotanical prospection in all regions of Cameroon, and was used to prepare an oral hypoglycemic product. This preparation required 9 steps focused on the characterization of the plant species, and the standardization of the ethnopharmacological preparation by a multidisciplinary team of scientists with expertise in botany, ecology, pharmacognosy and pharmacology. Resultantly, four galenic formulations of hypoglycemic medications were produced. A relationship between these four formulations was described as follow: One spoon of oral suspension (10 ml)=one sachet of powder=2 tablets=3 capsules. Hence, our research provides new insight into a drug discovery approach that could alleviate the major problems affecting traditional medicine and enhance its effectiveness in addressing health care in developing and undeveloped countries.