Antimalarial,antiplasmodial and analgesic activities of root extract of Alchornea laxiflora

Context: Alchornea laxiflora (Benth.) Pax. &; Hoffman (Euphorbiaceae) root decoctions are traditionally used in the treatment of malaria and pain in Nigeria.

Objective: To assess the antimalarial, antiplasmodial and analgesic potentials of root extract and fractions against malarial infections and chemically-induced pains.

Material and methods: The root extract and fractions of Alchornea laxiflora were investigated for antimalarial activity against Plasmodium berghei infection in mice, antiplasmodial activity against chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of Plasmodium falciparum using SYBR green assay method and analgesic activity against experimentally-induced pain models. Acute toxicity study of the extract, cytotoxic activity against HeLa cells and GCMS analysis of the active fraction were carried out.

Results: The root extract (75–225?mg/kg, p.o.) with LD₅₀ of 748.33?mg/kg exerted significant (p?P. berghei infection in suppressive, prophylactive and curative tests. The root extract and fractions also exerted moderate activity against chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of P. falciparum with the ethyl acetate fraction exerting the highest activity with IC₅₀ value of 38.44?±?0.89?μg/mL (Pf 3D7) and 40.17?±?0.78?μg/mL (Pf INDO). The crude extract was not cytotoxic to HeLa cells with LC₅₀ value >100?μg/mL. The crude extract and ethyl acetate fraction exerted significant (p?Discussion and conclusions: These results suggest that the root extract/fractions of A. laxiflora possess antimalarial, antiplasmodial and analgesic potentials and these justify its use in ethnomedicine to treat malaria and pain.     

Antimalarial and antiplasmodial activity of husk extract and fractions of Zea mays

Context: Zea mays L. (Poacae) husk decoctions are traditionally used in the treatment of malaria by various tribes in Nigeria.

Objective: To assess the antimalarial and antiplasmodial potentials of the husk extract and fractions on malaria parasites using in vivo and in vitro models.

Materials and methods: The ethanol husk extract and fractions (187–748?mg/kg, p.o.) of Zea mays were investigated for antimalarial activity against Plasmodium berghei using rodent (mice) malaria models and in vitro activity against chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of Plasmodium falciparum using the SRBR green assay method. Median lethal dose and cytotoxic activities against HeLa and HEKS cells were also carried out. The GCMS analysis of the most active fraction was carried out.

Results: The husk extract (187–748?mg/kg, p.o.) with LD₅₀ of 1874.83?mg/kg was found to exert significant (p?P. berghei infection in suppressive, prophylactive and curative tests. The crude extract and fractions also exerted prominent activity against both chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of P. falciparum with the ethyl acetate fraction exerting the highest activity with IC₅₀ values of 9.31?±?0.46?μg/mL (Pf 3D7) and 3.69?±?0.66?μg/mL (Pf INDO). The crude extract and fractions were not cytotoxic to the two cell lines tested with IC₅₀ values of?>100?μg/mL against both HeLa and HEKS cell lines.

Discussion and conclusion: These results suggest that the husk extract/fractions of Zea mays possesses antimalarial and antiplasmodial activities and these justify its use in ethnomedicine to treat malaria infections.     

In vivo antiplasmodial activities of aqueous extract of Bridelia ferruginea stem bark against Plasmodium berghei berghei in mice

Context: Bridelia ferruginea Benth (Euphorbiaceae) is an indigenous medicinal plant in Nigeria. It is usually a gnarled shrub which sometimes reaches the size of a tree in suitable condition. Decoctions of parts of this plant have been employed in ethno medicine in many parts of Africa for treatment of many ailments including malaria fever.

Objective: In vivo antiplasmodial activity of aqueous stem bark extract of BF was investigated against Plasmodium berghei-infected mice.

Materials and methods: The aqueous stem bark extract of BF (100–400?mg/kg) was administered orally to P. berghei-infected mice in both early and established models of antiplasmodial studies.

Results: The extract exhibited significant (p?<?0.05) antiplasmodial activity in early and established infection tests with a considerable mean survival time comparable to that of chloroquine, 10?mg/kg. The oral LD₅₀ obtained was greater than 5000?mg/kg in mice.

Discussion and conclusions: The findings show that aqueous stem bark extract of Bridelia ferruginea possesses considerable antiplasmodial activity which can be developed in malaria therapy.     

Antipyretic and antimalarial activities of Solenostemon monostachyus

Context: Solenostemon monostachyus P. Beauv (Lamiaceae) is an important herb used traditionally in the treatment of malaria, fever, and other diseases.

Objectives: Antiplasmodial and antipyretic activities of S. monostachyus aerial extract were evaluated to ascertain the folkloric claim of its antimalarial and antipyretic activities.

Materials and methods: The extract (75–225?mg/kg) and fractions (chloroform and aqueous; 150?mg/kg) of S. monostachyus were investigated for suppressive, prophylactic, and curative antiplasmodial activities against chloroquine-sensitive Plasmodium berghei infections in Swiss albino mice and for antipyretic activity against 2,4-dinitrophenol and yeast-induced pyrexia. Artesunate (5?mg/kg) and pyrimethamine (1.2?mg/kg) were used as positive controls for antiplasmodial models. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice.

Results: The extract/fractions progressively reduced parasitaemia induced by chloroquine sensitive P. berghei infection in prophylactic (28.48–71.72%), suppressive (12.52–72.47%), and curative (22.4–82.34%) models in mice. These reductions were statistically significant (p?<?0.01–0.001). They also improved significantly (p?<?0.01–0.001) the mean survival time (MST) from 12.26 to 25.63?d relative to control (11.36?d). The activities of extract/fractions were incomparable with that of the standard drugs used (artesunate and pyrimethamine). The extract exerted prominent inhibition of pyrexia on dinitrophenol (87.33–90.11%, 5?h) and yeast (56.22–65.33, 5?h) induced pyrexia. Inhibition was significant (p?<?0.05–0.001) from 3 to 5?h post-administration of extract and in a dose-dependent fashion.

Conclusion: The plant may possess antiplasmodial and antipyretic effects which may in part be mediated through the chemical constituents of the plant.     

Antiplasmodial activity of aqueous extract of Berberis aristata roots against Plasmodium berghei-infected BALB/c mice

Abstract

Context: The rising problem of resistance to present antimalarial drugs stresses the need to look for newer antiplasmodial components with effective modes of action. The roots of Berberis aristata DC. (Berberidaceae) are used in the traditional medicine for malaria in various parts of India.

Objective: The objective of this study was to evaluate antiplasmodial activity of B. aristata roots extract for the validation of its traditional medicinal use.

Material and methods: Aqueous root extract of Berberis aristata (AREBA) was screened for its in vitro as well as in vivo antiplasmodial activity against lethal rodent malaria parasite Plasmodium berghei NK65. In vitro activity was evaluated against schizont maturation of P. berghei using various concentrations ranging from 1 to 100?µg/mL. For in vivo studies, AREBA at the doses of 150, 250, 350, and 650?mg/kg/d was administered to P. berghei infected BALB/c mice orally for 4 consecutive days (D0–D3).

Results: AREBA showed in vitro antiplasmodial activity with an IC₅₀ value of 40?µg/mL. In vivo studies demonstrated a variable dose-dependent chemosuppression with higher efficacy at lower doses. At a dose of 350?mg/kg/d, the suppressive and preventive activities were found to be 67.1% and 53.9%, respectively, followed by enhancing mean survival period up to 12.8?d for the curative assay versus 7.5?d for the untreated mice.

Discussion and conclusion: These results provide relevant scientific evidences for the traditional medicinal use of this plant as malaria remedy and further advocates the isolation and characterization of active antiplasmodial principle from this plant.     

Anti-inflammatory and anti-proliferative activities of the wild edible cruciferous: Diplotaxis simplex

Context The present study deals with new biological properties of the wild edible Diplotaxis simplex (Viv.) Spreng (Brassicaceae).

Objectives The current study evaluates the antioxidant, the anti-inflammatory and the anti-cancer properties of ethyl acetate and ethanol extracts from D. simplex flowers.

Materials and methods The anti-proliferative activity of the extracts (10–70?μg/mL) was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) against human colon cancer cell line Caco-2. The anti-inflammatory potential was evaluated by the inhibitory effect of the extracts (1.5–7.5?mg/mL) on phospholipase A2 activity as well as on carrageenan-induced paw oedema in mice. Extracts (200?mg/kg) or indomethacin (50?mg/kg) as positive control were injected intraperitoneally for albino mice prior to the induction of the oedema by carrageenan. Antioxidant activities were investigated using various complementary methods.

Results Flower extracts contained a high level of polyphenolics (17.10–52.70?mg GAE/g) and flavonoids (74.20–100.60?mg QE/g), which correlate with its appreciable antioxidant potential in β-carotene peroxidation (IC₅₀ value: 12.50–27.10?μg/mL), DPPH^? radical-scavenging (IC₅₀ value: 0.20–0.40?mg/mL), Fe^3+?reducing (EC₅₀ value: 0.10–0.14?mg/mL) and Fe^2+?chelating (IC₅₀ value: 0.20–0.60?mg/mL) assays. These extracts were effective in inhibiting cancer cell growth (IC₅₀ value: 62.0–63.25?μg/mL). Besides, the ethyl acetate extract inhibited phospholipase A2 activity (IC₅₀ value: 2.97?mg/mL) and reduced the paw oedema in mice (from 0.38?±?0.01 to 0.24?±?0.01?cm), 4?h post-carrageenan challenge.

Conclusion These data suggest that D. simplex may be useful as a candidate in the treatment of inflammation and the colon cancer.     

Antinociceptive activity and chemical composition of Wei–Chang–An–Wan extracts

Abstract

Context: Currently, famous traditional Chinese medicine formulas have undergone re-evaluation and development in China. Wei–Chang–An–Wan (WCAW) as one of them has been used for treating various gastrointestinal diseases for several decades. The secondary development of WCAW is in progress so as to interpret the effective material basis or find new pharmacological activity.

Objective: To evaluate the antinociceptive effect of methanol extract of WCAW (ME) as well as four fractions (P.E., EtOAc, n-BuOH, H₂O) and obtain information on the correlation between the contents of the fractions and antinociceptive effect.

Materials and methods: ME was divided into four parts extracted by petroleum ether, ethyl acetate and n-butanol. Antinociceptive activity was evaluated by three models of acetic acid–induced writhing, formalin and hot-plate test in mice after repetitive administration of ME at 200, 400 or 800?mg/kg, P.E. 132?mg/kg, EtOAc 106?mg/kg, n-BuOH 176?mg/kg and H₂O 176?mg/kg for six days. The chemical compounds were analyzed by HPLC-ESI-MS.

Results: ME at 800?mg/kg inhibited acid-induced writhing by 84.69%, and reduced the licking time of second phase in formalin test by 53.23%. The inhibition rates in acid-induced writhing of P.E., EtOAc, n-BuOH and H₂O were 27.79, 33.85, 38.97 and 37.69%, respectively, and in formalin test about 50%. They had no effect on the hot-plate test. HPLC-ESI-MS analysis showed that 68 chemical compounds were detected and 41 compounds were identified from ME.

Discussion and conclusion: The results obtained herein indicate that WCAW possesses the antinociceptive activity that provides a new aspect in clinical application.     

Antimalarial and cytotoxic quassinoids from the roots of Brucea javanica

Two new quassinoids, brujavanol A (1) and brujavanol B (2), along with five known quassinoids (3–7), were isolated from the roots of Brucea javanica. Their structures were elucidated by spectroscopic methods. The antimalarial and cytotoxic activities of the isolated compounds were also assessed. Compounds 1 and 2 exhibited significant in vitro cytotoxicity against human oral cavity cancer (KB) cells with IC₅₀ values of 1.30 and 2.36 μg/ml, respectively, whereas compound 3 showed excellent antiplasmodial activity against the Plasmodium falciparum strains, K1 (IC₅₀ = 0.58 μg/ml).     

Hydroalcoholic extract of Myrtus communis can alter anxiety and sleep parameters: a behavioural and EEG sleep pattern study in mice and rats

Context: Myrtus communis L. (Myrtaceae), myrtle, is an evergreen shrub with strong antibacterial, anti-inflammatory, antihyperglycemic and antioxidant activities. Also, it is used as a sedative-hypnotic plant in Iranian traditional medicine.

Objective: This study evaluates the effect of 80% ethanolic extract of M. communis leaves on sleep and anxiety in mice and rats.

Materials and methods: Male NMRI mice were subjected to open field, righting reflex, grip strength and pentylentetrazole-induced seizure tests. Male Wistar rats were used to evaluate the alterations in rapid eye movement (REM) and non-REM (NREM) sleep. They were treated with 25–400?mg/kg doses of the extract intraperitoneally.

Results: The applied doses (50–200?mg/kg) of M. communis extract increased vertical (ED_50?=_?40.2?±?6.6?mg/kg) and vertical and horizontal activity (ED_50?=_?251?±?55?mg/kg), while treatment with 200 and 400?mg/kg attenuated muscle tone significantly compared to vehicle treated animals (p?<?0.001 for all) in a dose-independent manner. Also, a significant hypnotic and not anticonvulsant effect was observed when animals were treated with 200?mg/kg of the extract (p?<?0.01). In this regard, electroencephalography results showed that REM sleep time was decreased (2.4?±?0.5%), while total and NREM sleep times were increased significantly compared to the control group of mice (82.5?±?7.6%).

Discussion and conclusion: The data show the anxiolytic and muscle relaxant effect of the extract without anticonvulsant activities. The anxiolytic, myorelaxant and hypnotic effects without effect on seizure threshold are in line with the effect of a alpha 2 GABA receptor agonist.     

Male contraceptive efficacy of poly herbal formulation,contracept-TM,composed of aqueous extracts of Terminalia chebula fruit and Musa balbisiana seed in rat

Context: Terminalia chebula Retz (Combretaceae) and Musa balbisiana Colla (Musaceae) have a traditional reputation as a male contraceptive.

Objective: To determine the hypo-testicular activity of aqueous extracts of Terminalia chebula (fruit) and Musa balbisiana (seed) separately, and in composite manner at the ratio of 1:1 named as ‘Contracept-TM’ compared to cyproterone acetate (CPA), for developing a polyherbal contraceptive.

Materials and methods: The separate extract of above said plants or ‘Contracept-TM’ at the dose of 40?mg/100?g body weight of rat/day or CPA at 2?mg/100?g body weight of rat/day was administered for 28 days. Spermiological, androgenic and oxidative stress sensors, LD₅₀ and ED₅₀/100?g body weight values were measured.

Results: Treatment of individual, ‘Contracept-TM’ or CPA resulted significant decrease in the count of spermatogonia A (36.36–49.09%), pre-leptotene spermatocyte (19.11–55.30%), mid-pachytene spermatocyte (28.65–47.28%) and step 7 spermatid (29.65–51.59%). Activities of testicular Δ⁵, 3β (21.25–48.02%),17β-hydroxysteroid dehydrogenases (29.75–55.08%), catalase (19.06–43.29%) and peroxidase (30.76–62.82%), levels of testosterone (28.15–63.44%), testicular cholesterol (19.61–49.33%), conjugated diene (29.69–84.99%) and thiobarbituric acid reactive substances (41.25–86.73%) were elevated compare to the control. The ED₅₀ and LD₅₀ values were 40?mg and 5.8?g (T. chebula), 48?mg and 6.3?g (M. bulbisiana), 40?mg and 6.0?g (‘Contracept-TM’), respectively.

Discussion and conclusion: The said spermiological and androgenic sensors’ levels were decreased significantly by ‘Contracept-TM’ than its constitutional individual plant extract and it may be comparable to standard anti-testicular drug like CPA. So, it may be concluded that above polyherbal formulation is potent for inducing hypo-testicular activity.     

Influence of Amodiaquine on the Antimalarial Activity of Ellagic Acid: Crystallographic and Biological Studies

In the search for new antimalarial drugs, design of hybrid molecules is recommended to improve biological activity and to decrease the risk of parasite resistance development. Ellagic acid, as an inhibitor of Plasmodium glutathione, presents an original mode of action and thus appears as a promising antiplasmodial compound. A new complex (AQ–EA) consisting of the well‐known antimalarial drug, amodiaquine, and ellagic acid was obtained. The studied crystal structure of AQ–EA showed that the triclinic centrosymmetrical unit cell of the crystal contains two molecules of amodiaquine (AQ) and two symmetrically independent molecules of ellagic acid (EA). The packing of the molecules in the crystal is dominated by hydrogen bonds between AQ and EA. The antiplasmodial activity of the hybrid complex AQ–EA was also determined and compared with the values of IC₅₀ for AQ and EA separately. Potentiation assays between both molecules were conducted to understand the pharmacological interactions between AQ and EA against Plasmodium falciparum in vitro. The hybrid complex AQ–EA (IC₅₀ of 47 nm ) showed improved antiplasmodial activity in comparison with EA alone.     

Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea

Context: There is an unmet need to discover new treatments for Alzheimer’s disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae).

Objective: The objective of this study is to quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities and cell cytotoxicity.

Materials and methods: Plant stem, leaves and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0.02–200?μg/mL. Plant DPPH radical scavenging activity, reducing power, and total phenolic and flavonoid contents were determined, and cytotoxicity evaluated using human hepatocytes.

Results: Carpolobia lutea exhibited concentration-dependent anti-AChE activity. The most potent inhibitory activity for the stem was the crude ethanol extract and hexane stem fraction oil (IC₅₀?=?140?μg/mL); for the leaves, the chloroform leaf fraction (IC₅₀?=?60?μg/mL); and for roots, the methanol, ethyl acetate and aqueous root fractions (IC₅₀?=?0.3–3?μg/mL). Dose-dependent free radical scavenging activity and reducing power were observed with increasing stem, leaf or root concentration. Total phenolic contents were the highest in the stem: ～632?mg gallic acid equivalents/g for a hexane stem fraction oil. Total flavonoid content was the highest in the leaves: ～297?mg quercetin equivalents/g for a chloroform leaf fraction. At 1?μg/mL, only the crude ethanol extract oil was significantly cytotoxic to hepatocytes.

Discussion and conclusions: Carpolobia lutea possesses anti-AChE activity and beneficial antioxidant capacity indicative of its potential development as a treatment of Alzheimer’s and other diseases characterized by a cholinergic deficit.     

Antiplasmodial activity of extracts of 25 cyanobacterial species from coastal regions of Tamil Nadu

Context: Marine cyanobacteria offer considerable potential to isolate new antimalarials to meet a pressing need of our times.

Objective: To explore the antiplasmodial properties of marine cyanobacteria.

Materials and methods: Cyanobacterial samples collected from the coastal regions of Tamil Nadu were identified using light microscopy, and the strains were cultivated in ASN-III medium. Organic extracts (0–100?µg?mL^?1) of 25 in vitro mass-cultivated cyanobacteria, prepared using methanol: chloroform mixture (1:1?v/v) were evaluated for their antiplasmodial activity against chloroquine-sensitive and -resistant strains of Plasmodium falciparum by fluorescence-based SYBR Green I assay where chloroquine was used as a control. To detect the toxic effects of cyanobacterial extracts against red blood cells, the invasion, maturation, and growth rate of malarial parasites in cyanobacterial extracts pre-treated versus untreated erythrocytes were quantified microscopically. Mammalian cell line (HeLa) was used to determine cyanobacterial extract toxicity using the MTT assay.

Results: The extracts of Lyngbya aestuarii Liebm. ex Gomont CNP 1005 (C12) Oscillatoria boryana BDU 91451 (C22) and Oscillatoria boryana Bory ex Gomont BDU 141071 (C18) showed promising antiplasmodial activity (IC₅₀?=?18, 18, and 51?μg?mL^?1 respectively) against Pf3D7. Pretreatment of red blood cells with IC₁₀₀ of C12, C18, and C22 (40, 100, and 40?µgmL^?1, respectively) did not significantly influence the invasion, maturation, and growth rate of malarial parasites in comparison with untreated RBC controls suggesting a lack of toxicity to host cells. MTT assay based IC₅₀ (>200?μg?mL^?1) of these extracts against HeLa cell line also indicates their high selectivity against the malaria parasite.

Discussion and conclusion: These exploratory studies suggest the possibilities of development of new antimalarial compounds from marine cyanobacteria.     

Screening of antidepressant activity and estimation of quercetin from Coccinia indica using TLC densitometry

Abstract

Context: Coccinia indica Naud (Cucurbitaceae) has been traditionally used for the treatment of depression but these claims have not been validated.

Objectives: The objective of this study is to investigate antidepressant activity of various extracts and fractions of C. indica aerial parts, and to estimate content of quercetin in the plant using TLC densitometry.

Materials and methods: Coccinia indica aerial parts were successively extracted using solvents in increasing order of polarity, namely n-hexane, chloroform, methanol, and water. Various extracts were evaluated for antidepressant activity at doses of 200 or 400?mg/kg, p.o., upon acute administration in mice using the forced swim test (FST). The bioactive extract was partitioned successively using solvents in increasing order of polarity, namely n-hexane, ethyl acetate, and n-butanol. All fractions were also screened for antidepressant activity at doses of 25 or 50?mg/kg, p.o., upon acute administration in mice.

Results: The methanol extract significantly reduced the duration of immobility in FST at dose of 400?mg/kg without affecting locomotor activity in open field test, thus, confirmed its antidepressant activity, which was statistically equivalent to the standard drug (imipramine, 15?mg/kg, i.p.). Ethyl acetate fraction (EAF) exhibited antidepressant activity at 50?mg/kg. Comparative TLC fingerprint studies confirmed the presence of quercetin in methanol extract and EAF. Quercetin was used as a chemical marker to standardize C. indica aerial parts using the validated TLC densitometric method, and the content of quercetin was found to be 0.00172% w/w.

Conclusions: The present studies scientifically validated traditional claims of C. indica for antidepressant activity.     

The mutagenic,antimutagenic and antioxidant properties of Hypericum lydium

Context: There is a growing market demand for Hypericum sp., a pharmacologically active plant that has been traditionally used to treat various ailments. However, there have been limited studies on the extract or essential oil of Hypericum lydium Boiss (Hypericaceae).

Objective: This study investigates for the first time the antioxidant, mutagenic and antimutagenic activity of an ethanol extract of H. lydium.

Material and methods: Ethanol extract from aerial parts of H. lydium harvested from Turkey were tested for this mutagenic and antimutagenic activities (2.0–0.002?mg/plate) using Ames Salmonella/microsome test system. 4-Nitro-o-phenylenediamine (4-NPD) (3?μg/plate) for the Salmonella typhimurium TA98 and sodium azide (NaN₃) (8?μg/plate) for the S. typhimurium TA100 were used as positive controls. The antioxidant activity, total antioxidant activity and phenolic constituent of the extract (2.0–0.002?mg/mL) was determined by the inhibition of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), β-carotene-linoleic acid model and by means of Folin–Ciocalteu reagent, respectively.

Results: The extract showed no sign of mutagenicity at the tested concentrations (0.002–2.0?mg/mL), and showed concentration-dependent antimutagenic activity against NaN₃ and 4-NPD ranging from 26.8 to 81.5%. The extract was found to be an efficient scavenger of DPPH (IC₅₀ 0.165?±?0.23?mg/mL) and to inhibit β-carotene-linoleic acid bleaching (IC₅₀ 0.39?±?0.11?mg/mL).

Discussion and conclusion: These findings indicate ethanol extract of H. lydium to be a safe and effective agent that may be incorporated into new strategies for the prevention of cancer and mutagenesis.     

Bioassay-Guided Isolation of Antimalarial Triterpenoid Acids from the Leaves of Morinda lucida.

Abstract

The EtOH, CH₂Cl₂, and petroleum ether extracts from Morinda lucida. Benth. leaves have been shown to exhibit an in vitro. antiplasmodial activity against a chloroquine-sensitive Plasmodium falciparum. strain with IC₅₀ values 5.7 ± 1.3, 5.2 ± 0.8, and 3.9 ± 0.3 µg/mL, respectively. In vivo., at a daily oral dose of 200 mg/kg body weight, they produced at least 62.5%, 67.5%, and 72.2% reduction of parasitemia in mice infected with Plasmodium berghei berghei., respectively. A bioassay-guided fraction of the most active petroleum ether extract resulted in the isolation of two known triterpenic acids as ursolic acid 1 and oleanolic acid 2. In vitro., 1 and 2 exhibited an antiplasmodial activity with IC₅₀ values of 3.1 ± 1.3 and 15.2 ± 3.4 µg/mL, respectively. In vivo., at a daily dose of 200 mg/kg body weight, they produced 97.7% and 37.4% chemosuppression, respectively. However, all tested samples were inactive in vitro. against chloroquine-resistant Plasmodium falciparum. (K1) at the highest tested concentration of 25 µg/mL.     

Azadirachta indica extract–artesunic acid combination produces an increased cure rate of Plasmodium berghei-infected mice

Context: Available artemisinin-combination therapies (ACTs) are expensive. Various traditional herbal remedies for malaria involve plants, proven scientifically to have antiplasmodial effects, e.g., Azadirachta indica A. Juss. (Meliaceae).

Objective: Combination of an artemisinin-based compound and a medicinal herb extract will provide an indigenous alternative/herb-based ACT.

Materials and methods: The in vivo schizontocidal activity of the crude aqueous extract of 100, 500, and 1000?mg/kg of A. indica fresh leaves (NCE) and 6, 15, and 20?mg/kg of artesunic acid were determined, alone and in combination, while keeping the dose of artesunic acid constant at 15?mg/kg, using the Peter’s 4-day suppressive test and Swiss albino mice. The ED₅₀ was calculated from the dose-response relationships. Percentage survival and cure were also determined.

Results: The average yield of two extractions of NCE was 8.33?±?1.67%. Combination of 1000?mg/kg of NCE and 15?mg/kg of artesunic acid, produced a significant reduction of parasitemia (96.87%), compared to 20?mg/kg of artesunic acid alone (68.14%). The combination had an ED₅₀ of 0.58?mg/kg while that of artesunic acid alone was 8.814?mg/kg. The combinations of NCE with artesunic acid produced a cure, although the artesunic acid did not produce a cure in 30?d.

Discussion: NCE increased the activity of artesunic acid in terms of reduction in parasitemia, and increased survival time and cure rate.

Conclusion: The combination of an artemisinin and aqueous extract of neem leaf is possible, providing a potentiated reduction of parasitemia, and increased cure rate.     

A mechanistic evaluation of the traditional uses of Nepeta ruderalis in gastrointestinal and airway disorders

Context: Nepeta ruderalis Buch.-Ham. (Lamiaceae), locally known as Badranj Boya, is an aromatic herb used traditionally as an antispasmodic, antidiarrhoeal, and anti-asthamatic remedy.

Objective: Aqueous methanolic extract of N. ruderalis was studied to investigate its traditional uses.

Materials and methods: Study was conducted from September 2015 to February 2016. In vitro spasmolytic and broncho-relaxant activity of crude extract of N. ruderalis (whole plant) was evaluated at 0.01–10?mg/mL final bath concentration in isolated rabbit jejunum and tracheal tissues, using PowerLab data acquisition system (Transonic Systems Inc., Ithaca, NY). In vivo antidiarrhoeal activity was evaluated in castor oil-induced diarrhoeal mice at the dose of 300 and 500?mg of crude extract orally.

Results: Crude extract of N. ruderalis completely relaxed spontaneously contracting, high K⁺ (80?mM) and carbachol (1?μM) induced contracted jejunum with an EC₅₀ value of 5.85 (5.45–6.27), 4.0 (3.80–4.23) and 2.86 (2.48–3.29), similar to verapamil. Nr.Cr relaxed high K⁺ and carbachol induced contractions, at 5 and 10?mg/mL with an EC₅₀ value of 2.37 (2.11–2.67) and 3.26 (2.9–3.67), respectively, and also displaced calcium concentration–response curves toward right at 0.1 and 0.3?mg/mL. Nr.Cr exhibited antidiarrhoeal protection at a dose of 300 and 500?mg/kg, similar to verapamil, whereas no acute toxicity signs were seen up to 5?g/kg in healthy mice.

Discussion and conclusion: Results suggest the presence of spasmolytic and broncho-relaxant effects in the crude extract of N. ruderalis, possibly mediated through calcium channel-blocking activity, providing the pharmacological basis for its traditional uses in gastrointestinal and airway disorders.     

In vitro immunomodulatory activity and in vivo anti-inflammatory and analgesic potential with gastroprotective effect of the Mediterranean red alga Laurencia obtusa

Context: Red algae have been recognized as a rich natural source of compounds possessing interesting biological and pharmacological activities.

Objective: This work investigates anti-inflammatory, analgesic and gastroprotective activities of MeOH/CH₂Cl₂ crude extract and its fractions F1 (50% MeOH) and F2 (80% MeOH) from the whole alga plant Laurencia obtusa Hudson (Rhodomelaceae).

Materials and methods: Anti-inflammatory activity was evaluated in vitro using cytometric bead array (CBA) technology to follow up the secretion of tumour necrosis factor alpha (TNF-α) in lipopolysaccharide activated THP-1 monocytic cells at doses of 10–250?μg/mL and in vivo using carrageenan-induced paw oedema in Wistar rats at doses of 25, 50, 100 and 200?mg/kg. Crude extract and fractions were tested at the doses of 25, 50, 100 and 200?mg/kg for peripheral and central analgesic activity by acetic acid-induced writhing test and hot-plate method, respectively, in Swiss albino mice. Gastroprotective activity was evaluated using HCl/ethanol-induced gastric ulcer test in rats at doses of 25, 50, 100 and 200?mg/kg.

Results: Crude extract, F1 and F2 showed an interesting inhibition of TNF-α secretion with IC₅₀ values of 25, 52 and 24?μg/mL, respectively, and a significant anti-inflammatory activity in vivo (p?< 0.01), 3?h after carrageenan injection, the oedema inhibition was 55.37%, 52.18% and 62.86%, respectively, at the dose of 100?mg/kg. Furthermore, they showed a significant peripheral analgesic activity with 53.79%, 55.92% and 57.37% (p?< 0.01) of writhing inhibition, respectively. However, no significant activity was found in the hot-plate test. An interesting gastroprotective effect was observed with crude extract and its fractions F1 and F2 with a gastric ulcer inhibition of 65.48%, 77.42% and 81.29%, respectively, at the dose of 50?mg/kg.

Discussion and conclusion: These results suggest that L. obtusa might be used as a potential source of natural anti-inflammatory and analgesic agents with gastroprotective effect.     

Anti-inflammatory,free radical scavenging and alpha-glucosidase inhibitory activities of Hamelia patens and its chemical constituents

Context Hamelia patens Jacq. (Rubiaceae) is traditionally used to treat wounds, inflammation and diabetes. However, there is still a lack of scientific evidence to support these applications.

Objective The objective of this study is to evaluate the anti-inflammatory, antioxidant and antidiabetic activities of Hamelia patens, and identify its bioactive compounds.

Materials and methods Four extracts were obtained by maceration and liquid–liquid extraction: HEX, DCM–EtOAc, MeOH–EtOAc and MeOH–Aq. The anti-inflammatory effect was evaluated orally on rat paw carrageenan-induced oedema over 6?h (50, 200 and 500?mg/kg), and topically in mouse ear oedema induced by 12-tetradecanoylphorbol-13-acetate (TPA) after 4?h (0.5 and 1?mg/ear). We also evaluated myeloperoxidase levels in ear tissue, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability, and in vitro α-glucosidase inhibition. The chemical compounds were separated by column chromatography and identified by spectroscopic analysis.

Results We found that the oral administration of the HEX extract at 500 and 200?mg/kg significantly decreased the carrageenan-induced inflammation after 1 and 3?h, respectively. The MeOH–EtOAc extract significantly inhibited myeloperoxidase activity (83.5%), followed by the DCM–EtOAc extract (76%), β-sitosterol/stigmasterol (72.7%) and the HEX extract (55%), which significantly decreased oedema induced by TPA at both doses, giving a similar effect to indomethacin. We also found that the MeOH–EtOAc, MeOH–Aq and DCM–EtOAc extracts showed good DPPH scavenging activity (IC₅₀ values of 18.6, 93.9 and 158.2?μg/mL, respectively). The HEX extract showed the lowest α-glucosidase inhibition (an IC₅₀ value of 26.07?μg/mL), followed by the MeOH–EtOAc extract (an IC₅₀ value of 30.18?μg/mL), β-sitosterol/stigmasterol (IC₅₀ 34.6?μg/mL) and compound A ((6E,10E,14E,18E)-2,6,10,14,18,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, an IC₅₀ value of 114.6?μg/mL), which were isolated for the first time from Hamelia patens.

Discussion and conclusion Hamelia patens possesses anti-inflammatory, antioxidant and α-glucosidase inhibitory activities, which support its traditional use. These effects can be attributed to the identified compounds.