Piper retrofractum

Abstract: Aqueous extracts of nine medicinal plants were bioassayed against larvae of Culex quinquefasciatus Say and Aedes aegypt (L.). Among these plants, the long pepper, Piper retrofractum Vahl (Piperaceae), showed the highest level of activity against mosquito larvae. To gain more information on larvicidal activity of P. retrofractum, fresh fruits of this plant were extracted in water and the extracts made into powder and bioassayed against 3rd and 4th instar larvae of Cx. quinquefasciatus and Ae. aegypti in the laboratory. Extracts of unripe (001/3) and ripe (002/3 and 001/4) fruits showed different levels of activity against Cx. quinquefasciatus larvae. Extracts 001/3 and 002/3 were equi-toxic to a Bacillus sphaericus resistant and susceptible strains, both from Thailand. The ripe fruit extract 002/3 was somewhat more active against Ae. aegypti than Cx. quinquefasciatus. Another ripe fruit extract (001/4) was much more toxic to both mosquito species. Diluted solutions of the solid extract (002/3) in distilled water lost their larvicidal activity upon aging. Loss of activity at 25 degrees C was greater than that stored at 4 degrees C, and greater in water than in acetone solution.

Abstract: Alpha-glucosidase inhibitory activity of fifteen Indian medicinal plants has been evaluated by in vitro enzyme assay. Methanol extracts of Cyperus rotundus (tubers), Plumbago zeylanica (root), Symplocos racemosa (bark), and Terminalia arjuna (bark) had displayed 100% inhibition with the IC 50 value of 3.98 µg/ml, 3.46 µg/ml, 8.16 µg/ml and 0.69 µg/ml, respectively. Bark extract of Terminalia arjuna is highly effective against alpha- glucosidase activity even at nanogram concentration. Plant parts of Piper retrofractum (stem), Zingiber officinale (rhizome), Acorus calamus (rhizome), Picrorhiza kurroa (rhizome), Marsdenia tenacissima (stem), Clerodendron serratum (root), and Rubia cordifolia (root) are not effective and they require high concentration to exhibit inhibition. Potential plants that show maximum inhibition at low concentration (<10 µg/ml) were subjected to kinetic analysis to determine the mode of inhibition of the enzyme. Cyperus rotundus, Symplocos racemosa and Terminalia arjuna exhibited uncompetitive inhibition and Plumbago zeylanica had displayed mixed inhibition to alpha-glucosidase enzyme activity. From the enzyme assay, we infer that Cyperus rotundus, Plumbago zeylanica, Symplocos racemosa and Terminalia arjuna contain potential alpha-glucosidase inhibitors that can be exploited for its use in the treatment of diabetes.

Abstract: Purpose: To examine whether seven species of plants of genus Piper possess anti-cancer effects. Methods: One normal breast and three breast cancer cell lines were used to test cytotoxic effects over a period of 72 h using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The dried plants were extracted with methanol and dichloromethane, and the effective extract isolated by crystallization, acid/base extraction and column chromatography techniques. Fragmented DNA was purified by phenol/chloroform/isoamyl alcohol. Results : Methanol and dichloromethane extracts of Piper retrofractum , Piper betle , especiall y Piper nigrum , exhibited strong effect on MDA-MB-468. When the crude extract of P. nigrum was then separated by column chromatography, fraction D showed activity against both MCF-7 and MDA-MB-468 cells. Fraction DE that was isolated from D demonstrated a highly cytotoxic effect with IC50 values of 8.33 ± 1.27 and 7.48 ± 0.57 μg/ml on MCF-7 and MDA-MB-468 cells, respectively. Furthermore, fraction DF exhibited a strong cytotoxic effect only on MCF-7 with IC50 value of 6.51 ± 0.39 μg/ml. DNA smears of MCF-7 and MDA-MB-468 cells treated with fraction DE and DF were observed within 7 days. Conclusions: These results indicate that the compounds isolated from P. nigrum , viz, DE and DF, have cytotoxic effect on breast cancer cell lines. These fractions could be promising agent for breast cancer treatment. Further studies on the isolation, structural and mechanism elucidation of the active compound are still needed being carried out. Keywords : Cytotoxicity, Breast cancer, P. nigrum , DNA fragmentation