Aedes aegypti larvicide from the ethanolic extract of Piper nigrum black peppercorns.

Due to unavailability of a vaccine and a specific cure to dengue, the focus nowadays is to develop an effective vector control method against the female Aedes aegypti mosquito. This study aims to determine the larvicidal fractions from Piper nigrum ethanolic extracts (PnPcmE) and to elucidate the identity of the bioactive compounds that comprise these larvicidal fractions. Larvicidal assay was performed by subjecting 3rd to 4th A. aegypti instar larvae to PnPcmE of P. nigrum. The PnPcmE exhibited potential larvicidal activity having an LC50 of 7.1246 ± 0.1304 ppm (mean ± Std error). Normal phase vacuum liquid chromatography of the PnPcmE was employed which resulted in five fractions, two of which showed larvicidal activity. The most active of the PnPcmE fractions is PnPcmE-1A, with an LC50 and LC90 of 1.7101 ± 0.0491 ppm and 3.7078 ppm, respectively. Subsequent purification of PnPcmE-1A allowed the identification of the larvicidal compound as oleic acid.

Bidens pilosa L. (Asteraceae): Botanical Properties, Traditional Uses, Phytochemistry, and Pharmacology.

There are 230 to 240 known Bidens species. Among them, Bidens pilosa is a representative perennial herb, globally distributed across temperate and tropical regions. B. pilosa has been traditionally used in foods and medicines without obvious adverse effects. Despite significant progress in phytochemical and biological analyses of B. pilosa over the past few years, comprehensive and critical reviews of this plant are anachronistic or relatively limited in scope. The present review aims to summarize up-to-date information on the phytochemistry, pharmacology, and toxicology of B. pilosa from the literature. In addition to botanical studies and records of the traditional use of B. pilosa in over 40 diseases, scientific studies investigating the potential medicinal uses of this species and its constituent phytochemicals for a variety of disorders are presented and discussed. The structure, bioactivity, and likely mechanisms of action of B. pilosa and its phytochemicals are emphasized. Although some progress has been made, further rigorous efforts are required to investigate the individual compounds isolated from B. pilosa to understand and validate its traditional uses and develop clinical applications. The present review provides preliminary information and gives guidance for further basic and clinical research into this plant.

Antimicrobial activity of new phorbins from Jatropha curcas Linn. (Euphorbiaceae) leaves.

The crude methanol extract of Jatropha curcas leaves exhibited activity against Staphylococcus aureus, Bacillus subtilis, Mycobacterium phlei, Candida albicans, and Trichophyton mentagrophytes but was inactive against Escherichia coli, Pseudomonas aeruginosa, and Saccharomyces cerevisiae. In a bioassay-directed fractionation, two new phorbins were isolated and analysed by spectroscopic methods. Isolate 1 was characterized as an analogue of pheophytin b with a phytyl moiety containing three double bonds which are at positions P2/P3, P6/P7, and P10/P11. Compound 2 was characterized as methyl pheophorbide a with 132-OH and 17- and 17(1)-CH3 moieties. It is active against Serratia marcescens.

Cassiaindoline, a new analgesic and anti-inflammatory alkaloid from Cassia alata.

Cassiaindoline is a new dimeric indole alkaloid isolated from Cassia alata L. leaves whose structure was elucidated through spectroscopic analyses. It exhibited analgesic activity at a dosage of 125.0 mg/kg mouse and decreased the number of writhings induced by acetic acid by 49.4%. It also showed a 57.1% anti-inflammatory activity at a dosage of 75 mg/kg mouse.

Menthalactone, a new analgesic from Mentha cordifolia Opiz. Leaves.

* Author for correspondence and reprint requests Z. Naturforsch. 64c, 809-812 (2009); received May 7/July 23, 2009 Menthalactone, a new long-chain alkene with a bicyclic lactone moiety, was isolated as an analgesic constituent from the leaves of Mentha cordifolia Opiz. At a dosage of 100 mg/ kg mouse, it decreased the number of squirms induced by acetic acid by 67.3%. Statistical analysis using Kruskall Wallis one-way analysis of variance by ranks showed that menthalac-tone is different from the solvent control at alpha = 0.01 and approximates the analgesic activity of mefenamic acid at 0.001 level of significance.

Comparative anti-hyperglycemic potentials of medicinal plants.

Validation of the ethnobotanical use of the leaves of Artemisia vulgaris Linn. (Compositae), Eucalyptus tereticornis Sm. (Myrtaceae), Solanum nigrum Linn. (Solanaceae), and Vitex negundo Linn. (Verbenaceae); stems of Nopalea cochinellifera (Linn.) Salm-Dyck (Cactaceae); roots of Imperata cylindrica Beauv. (Gramineae); dried bark of Syzygium cumini (Linn.) Skeels (Myrtaceae) as anti-diabetic agents using the oral glucose tolerance test showed that only the bark of Syzygium cumini and the leaves of Vitex negundo and Eucalyptus tereticornis exhibited anti-hyperglycemic activities when fed simultaneously with glucose. At the same dosages of 5 mg/20 g mouse, Syzygium cumini-treated mice showed a significant decrease in blood glucose levels (BGLs) at 30 min (alpha=0.10) and from 45 min onwards at alpha=0.05. Vitex negundo exhibited greater anti-hyperglycemic activity than Eucalyptus tereticornis. Both showed a significant decrease in BGLs at 60 min but at alpha=0.05 for Vitex negundo and at alpha=0.07 for Eucalyptus tereticornis. There was no significant lowering in BGLs for Imperata cylindrica and Solanum nigrum while there was even an increase in BGLs for Nopalea cochinellifera and Artemisia vulgaris.

Antihyperglycaemic flavonoids from Syzygium samarangense (Blume) Merr. and Perry.

2',4'-Dihydroxy-3',5'-dimethyl-6'-methoxychalcone 1, its isomeric flavanone 5-O-methyl-4'-desmethoxymatteucinol 2 and 2'4'-dihydroxy-6'-methoxy-3'-methylchalcone 3 were isolated from the leaves of S. samarangense using a bioassay-directed scheme. In an oral glucose tolerance test, at a dosage of 1.0 mg/20 g mouse, 1 and 2 significantly (alpha = 0.05) lowered the blood glucose levels (BGLs) in glucose-hyperglycaemic mice when administered 15 min after a glucose load. When co-administered with glucose, only 1 showed a significant lowering of BGLs 45 min after its oral administration. When administered 15 min before glucose, none of the flavonoids showed a positive effect. Only 1 decreased significantly, at alpha = 0.05, the BGLs of alloxan-diabetic mice at t = 90-150 min.

Spasmolytic flavonoids from Syzygium samarangense (Blume) Merr. & L.M. Perry.

The hexane extract of Syzygium samarangense (Ss.Hex) dose-dependently (10-1000 microg/ ml) relaxed the spontaneously contracting isolated rabbit jejunum. Four rare C-methylated flavonoids with a chalcone and a flavanone skeleton were isolated from Ss.Hex and were subsequently tested for spasmolytic activity. All flavonoids, identified as 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (3), and 7-hydroxy-5-methoxy-6,8-dimethyl-flavanone (4), showed dose-dependent spasmolytic activity in the rabbit jejunum with IC50 values of 148.3 +/- 69.4, 77.2 +/- 43.5, 142.4 +/- 58.6 and 178.5 +/- 37.5 microg/ml (mean +/- SEM), respectively. The dihydrochalcone derivative of compound 1, 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (5), when tested for spasmolytic activity, did not significantly relax the smooth muscle relative to the other compounds. Verapamil, a standard spasmolytic, has an IC50 value of 0.16 +/- 0.04 microg/ml. This is the first report of the relaxant activity of chalcones, specifically of compounds 1-3.

Evaluation of the bioactivity of triterpene mixture isolated from Carmona retusa (Vahl.) Masam leaves.

The major constituent of Carmona retusa (Vahl.) Masam. leaves is an intractable mixture of triterpenes, namely alpha-amyrin (43.7%), beta-amyrin (24.9%), and baurenol (31.4%). At a dosage of 100mg/kg mouse, the triterpene mixture exhibited 51% analgesic activity but only showed 20% anti-inflammatory activity. Kruskal-Wallis one-way analysis of variance by ranks showed that the triterpene mixture is as active as mefenamic acid, a commercially available analgesic, at alpha = 0.01. The charcoal tracing test showed a 29% anti-diarrheal activity for the triterpene mixture, which increased to 55% at a dosage of 250 mg/kg mouse. At the higher dosage, the triterpene mixture differed significantly from its solvent control at alpha = 0.01. Results of the micronucleus test showed that the triterpene mixture did not exhibit mutagenic nor anti-mutagenic activity at alpha = 0.001. There was no significant decrease in blood glucose levels (bgl) in alloxan-induced diabetic mice after administration of the triterpene mixture. The triterpene mixture was inactive against Escherichia coli and possessed moderate activities against Staphylococcus aureus, Candida albicans, and Trichophyton mentagrophytes.

Prolyl endopeptidase inhibitors from Syzygium samarangense (Blume) Merr. & L. M. Perry.

Compounds isolated from the hexane extract of the leaves of Syzygium samarangense (Blume) Merr. & L. M. Perry were tested for inhibitory activity against the following serine proteases: trypsin, thrombin and prolyl endopeptidase. The compounds were identified as an intractable mixture of alpha-carotene and beta-carotene (1), lupeol (2), betulin (3), epi-betulinic acid (4), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (5), 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (6), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (7), 2',4'-dihydroxy-6'-methoxy-3'-methyldihydrochalcone (8) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (9). Hydrogenation of compounds 5, 6 and 7 yielded compound 8, 2'-hydroxy-4',6'-dimethoxy-3'-methyldihydrochalcone (10) and 2',4'-dihydroxy-6'-methoxy-3',5'-dimethyldihydrochalcone (11), respectively. The hydrogenated products of compounds 6 and 7 were also tested for enzyme inhibitory activity. In addition, beta-sitosterol (12) and beta-D-sitosterylglucoside (13) were also isolated. This is the first report of the isolation of compounds 1-6, 8 and 13 from this plant. Compounds 3-8 and 10 exhibited significant and selective inhibition against prolyl endopeptidase among three serine proteases. This is the first report of this kind of activity for all these compounds.

Bioactivity studies on beta-sitosterol and its glucoside.

Beta-sitosterol and beta-sitosteryl-beta-D-glucoside were isolated as analgesic constituents from the leaves of Mentha cordifolia Opiz. The acetic acid-induced writhing test showed that beta-sitosterol and beta-sitosteryl-beta-D-glucoside decreased the number of squirms induced by acetic acid by 70.0% and 73.0%, respectively, at a dose of 100 mg / kg mouse. Statistical analysis using the Kruskall Wallis one-way analysis of variance by ranks showed that these isolates approximate the analgesic activity of mefenamic acid at a 0.001 level of significance. The hot plate method confirmed their analgesic activities, as beta-sitosterol and beta-sitosteryl-beta-D-glucoside exhibited a 300% and 157% increase in pain tolerance, respectively, while mefenamic acid, a known analgesic, showed a 171% increase. Neither isolate exhibited antiinflammatory activity using the carrageenan-induced mouse paw oedema assay. Beta-sitosterol also exhibited anthelminthic and antimutagenic activities. In vitro tests using live Ascaris suum as test animals showed that the behaviour of worms treated with beta-sitosterol approximated that of the positive controls, Combantrin and Antiox. An in vivo micronucleus test showed that beta-sitosterol inhibited the mutagenicity of tetracycline by 65.3% at a dose of 0.5 mg /kg mouse. At the same dose, it did not exhibit chromosome-breaking activity.

Bioactivity studies on Cassia alata Linn. leaf extracts.

The hexane, chloroform and ethyl acetate extracts of the leaves of Cussia alata Linn. were tested for their antimutagenic, antifungal, analgesic, antiinflammatory and hypoglycaemic activities. At a dosage of 5 mg/20 g mouse, the hexane extract was analgesic as it reduced the number of squirms induced by acetic acid by 59.5%. Both the hexane and EtOAc extracts exhibited antiinflammatory activity at a dosage of 5 mg/20 g mouse with a 65.5% and 68.2% decrease in carrageenan-induced inflammation, respectively. The chloroform extract was antimutagenic, at a dosage of 2 mg/20 g mouse, with a 65.8% inhibition in the mutagenicity of tetracycline. It was also the most active against Trichophyton mentagrophytes, at a concentration of 50 mg/mL but it had no activity against Candida albicans. The hexane and EtOAc extracts showed some activity against both organisms, with the EtOAc extract being more active against C. albicans. The EtOAc extract was hypoglycaemic. At a dosage of 5 mg/20 g mouse, it decreased the blood sugar level of mice by 58.3%. Pharmacological studies showed that all extracts caused an immediate decrease in motor activity, enophthalmus, hyperemia, micturition and diarrhoea. At a dosage of 150 mg/20 g mouse, the EtOAc extract caused paralysis, screen grip loss and enophthalmus accompanied by drooping and closure of the eyelids.

A new antimutagen from Mentha cordifolia Opiz.

The CHCl(3) extract of Mentha cordifolia Opiz. showed antimutagenicity against tetracycline. An antimutagen was purified by solvent partitioning and repeated normal phase-vacuum liquid chromatography (NP-VLC) using a micronucleus test-guided isolation and purification. Spectral analyses showed that the isolated antimutagen is possibly 6,7-bis-(2,2-dimethoxyethene)-2,11-dimethoxy-2Z,4E,8E,10Z-dodecatetraendioic acid. It inhibited the mutagenicity of tetracycline by 68.7% at a dosage of 0.01 mg per 20 g mouse. Statistical analysis using Kruskal-Wallis one-way analysis of variance (ANOVA) by ranks showed that its variance differs from that of the solvent control group (tetracycline+dimethylsulfoxide (DMSO)) at alpha=0.001. Moreover, the isolated antimutagen did not exhibit mutagenic activity at the same dosage. Statistical analysis showed that it is not mutagenic at 0.001 level of significance because its variance differs from that of tetracycline.

Comparative potencies of nutraceuticals in chemically induced skin tumor prevention.

Four nutraceuticals, sugar beet roots, cucumber fruits, New Zealand spinach leaves, and turmeric rhizomes, were evaluated for their comparative effectiveness against dimethylbenz[a]anthracene (DMBA)-initiated and croton oil-promoted skin tumors. Three different protocols were used. The most effective protocol (Protocol 2) is the topical application of the nutraceuticals 1 h before croton oil. There was a decrease in the percent skin tumor incidence, a decrease in multiplicity of skin tumors, and a later onset of skin tumors compared with the positive control for all the nutraceuticals tested, with turmeric being the most potent, as evidenced by 30% skin tumor incidence, 87.2% decrease in skin tumors, and a 5-wk delay in skin tumor formation compared with the positive control. Topical application of the nutraceuticals daily for 5 days before DMBA and 1 h before croton oil (Protocol 1) and immediately after croton oil (Protocol 3) did not have an additional protective effect against skin tumors compared with Protocol 2. Kruskal-Wallis analysis of variance by ranks showed that Protocol 2 is the most effective, with the treatment groups belonging to different populations at the 0.05 level of significance compared with alpha = 0.20 for Protocols 1 and 3. Turmeric is the most potent nutraceutical, because the average number of tumors formed after application of tumeric is statistically different from the positive control at alpha = 0.01.